JP2016019374A - Control device, image forming apparatus, control method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve estimation accuracy of load torque of an electric motor. A control device for controlling an electric motor, wherein a time constant deriving unit 221 for deriving a mechanical time constant and an electric time constant corresponding to an actual measurement value of a rotation speed of the electric motor, and the electric motor are controlled. The estimated value calculated by inputting the control value to the motor nominal model updated with the derived mechanical time constant and the electric time constant, and the actually measured value are used as the derived mechanical time constant and the electric time constant. A load torque estimator 212 for calculating an estimated value of the load torque of the electric motor by inputting it into a torque estimation model updated with a time constant, and the motor nominal updated when calculating the estimated value The model and the torque estimation model are based on correction contents determined in advance according to a difference value between the estimated value and the actually measured value when the electric motor is controlled under a predetermined condition. It is characterized in that it is corrected accordingly. [Selection] Figure 2

Description

  The present invention relates to a control device, an image forming apparatus, a control method, and a program.

  Conventionally, a technique for estimating a load torque of an electric motor in real time is known. For example, Patent Literature 1 identifies a control model for an electric motor that is a control target, and uses a voltage value (control value) for controlling the electric motor and a rotation speed (actual value) of the electric motor. A technique for estimating the load torque of an electric motor is disclosed.

  According to Patent Document 1, since a load torque can be calculated in real time without providing a torque meter and fed back to the speed control of the electric motor, a control system that is not easily affected by fluctuations in the load torque can be achieved at low cost. Can be realized.

  However, in the case of the method of identifying the control model and estimating the load torque as in Patent Document 1, the load torque may not be correctly estimated due to the change in the state of the control target. This is because the characteristics of the controlled object change due to a change in the state of the controlled object, resulting in a characteristic different from the identified control model.

  The present invention has been made in view of the above problems, and an object thereof is to improve the estimation accuracy of the load torque of the electric motor.

The control device according to the embodiment of the present invention has the following configuration. That is,
A control device for controlling an electric motor,
Derivation means for deriving a mechanical time constant and an electric time constant of the electric motor corresponding to an actual measurement value of the rotation speed of the electric motor;
An estimated value of the rotational speed of the electric motor calculated by inputting a control value for controlling the electric motor to the motor nominal model updated with the derived mechanical time constant and electric time constant, and the electric motor Calculation means for calculating an estimated value of the load torque of the electric motor by inputting the measured value of the rotational speed of the motor to a torque estimation model updated by the derived mechanical time constant and electrical time constant. Have
The motor nominal model and the torque estimation model that are updated when calculating the estimated value are determined in advance according to a difference value between the estimated value and the actually measured value when the electric motor is controlled under a predetermined condition. The correction is made based on the correction content.

  According to each embodiment of the present invention, it is possible to improve the estimation accuracy of the load torque of the electric motor.

It is a figure which shows the hardware constitutions of the control apparatus which concerns on embodiment. It is a functional block diagram which shows the function implement | achieved by running a load torque estimation program. It is a figure which shows an example of the processing mode performed in an estimation part. It is a block diagram for controlling an electric motor and estimating load torque. It is a figure for demonstrating a motor nominal model. It is a figure for demonstrating the measuring method of the mechanical time constant of an electric motor. It is a figure for demonstrating the measuring method of the electric time constant of an electric motor. It is a figure which shows the relationship between the rotational speed of an electric motor, a mechanical time constant, and an electrical time constant. It is a flowchart which shows the flow of a load torque estimation process. It is a flowchart which shows the flow of a coil resistance value calculation process. It is a flowchart which shows the flow of a coil resistance value determination process. It is a flowchart which shows the flow of a failure diagnosis process. It is a figure which shows the relationship between temperature data and the fluctuation rate of a coil resistance value. It is a figure for demonstrating the measuring method of the mechanical time constant of an electric motor. It is a figure for demonstrating the measuring method of the electric time constant of an electric motor. It is a figure which shows the relationship between the load torque of an electric motor, a mechanical time constant, and an electrical time constant. It is a flowchart which shows the flow of a load torque estimation process. FIG. 2 is a diagram illustrating a schematic configuration when the control device according to the embodiment is applied to an image forming apparatus. FIG. 4 is a diagram illustrating a relationship between a processing mode of the image forming apparatus and processing executed in a control device. FIG. 6 is a diagram illustrating a relationship between an internal temperature of the image forming apparatus and an estimated value of load torque.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, the duplicate description is abbreviate | omitted by attaching | subjecting the same code | symbol.

[First Embodiment]
<1. Hardware configuration of control device>
First, the hardware configuration of the control device according to the present embodiment will be described. FIG. 1 is a diagram illustrating a hardware configuration of the control device 100 according to the present embodiment.

  As shown in FIG. 1, the control device 100 includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, and a RAM (Random Access Memory) 103. In addition, the control device 100 includes a storage device 104 and an interface unit 105. Note that each unit of the control device 100 is connected to each other via the bus 106.

  The CPU 101 is a computer that executes a load torque estimation program 110 stored in the storage device 104.

  The ROM 102 is a nonvolatile memory. The ROM 102 stores various programs and data necessary for the CPU 101 to execute the load torque estimation program 110. Specifically, a boot program such as BIOS (Basic Input / Output System) or EFI (Extensible Firmware Interface) is stored.

  The RAM 103 is a main storage device such as a DRAM (Dynamic Random Access Memory) or an SRAM (Static Random Access Memory). The RAM 103 functions as a work area that is expanded when the load torque estimation program 110 is executed by the CPU 101. The storage device 104 stores a load torque estimation program 110.

  The interface unit 105 is connected to the motor driving device 120 and transmits a control value for controlling the electric motor 130 to be controlled to the motor driving device 120. In addition, information indicating the state of the electric motor 130 to be controlled (actual value of rotation speed or actual value of position information) is received from the position / rotation speed detection unit 140 via the motor drive device 120.

  The interface unit 105 is connected to the input unit 150 and receives control information, processing mode information, temperature data, and the like input from the input unit 150. The control information is various instruction information for operating the electric motor 130, and the control information includes "target rotational speed", "target position", "operation start instruction", "operation stop instruction", and the like. As for information regarding the processing mode, which of a plurality of functions (processing modes) included in the estimation unit (details will be described later) among various functions realized by the CPU 101 executing the load torque estimation program 110 is executed. This is information for specifying. The temperature data is data indicating the ambient temperature of the electric motor 130.

  The interface unit 105 is connected to the display unit 160 and displays an estimated value of the load torque and a failure diagnosis result of the drive system including the electric motor 130 that are output when the load torque estimation program 110 is executed by the CPU 101. . Note that the output destination of the estimated value of the load torque and the failure diagnosis result is not limited to the display unit 160, and may be, for example, a predetermined storage device or another control device.

  The motor driving device 120 drives the electric motor 130 based on the control value transmitted from the interface unit 105. Also, the detection signal output from the position / rotation speed detection unit 140 is received and transmitted to the interface unit 105 as an actual rotation speed value or an actual position information value.

  The electric motor 130 is a DC motor, for example, and is driven by the motor driving device 120. The position / rotation speed detector 140 is attached to the electric motor 130 and outputs a detection signal (a signal indicating a rotation speed or a signal indicating a position). In the present embodiment, the position / rotation speed detector 140 includes, for example, a two-phase encoder and a one-phase photodetector. Alternatively, magnetic sensors such as FG (Frequency Generator) sensors and Hall element sensors are included.

  The input unit 150 is a device for inputting various types of information (control information, information regarding processing modes, temperature data, etc.) to the control device 100 via the interface unit 105. The display unit 160 is a device that displays various information transmitted from the control device 100 (estimated load torque value and drive system failure diagnosis result including the electric motor 130).

<2. Functional configuration of load torque estimation program>
Next, various functions realized when the load torque estimation program 110 is executed by the CPU 101 will be described. FIG. 2 is a functional configuration diagram showing various functions realized by the load torque estimation program 110 being executed by the CPU 101.

  In FIG. 2, a target rotational speed input unit 201 and a target position input unit 202 receive control information via the interface unit 105 and control a control target value (target rotational speed or target position) included in the received control information. Input to the unit 200. The operation instruction input unit 203 receives control information via the interface unit 105 and inputs an operation start instruction and an operation stop instruction included in the received control information to the control unit 200.

  The actual measurement value input unit 208 inputs the actual measurement value of the rotational speed of the electric motor 130 or the actual measurement value of the position information received via the interface unit 105 to the control unit 200.

  The control unit 200 starts control of the electric motor 130 when an operation start instruction is input. Specifically, a control value for controlling the electric motor 130 based on the input control target value (target rotation speed or target position) and the input rotation speed actual measurement value or position information actual measurement value. (Voltage value) is calculated. The control unit 200 continues to control the electric motor 130 until an operation stop instruction is input.

  The control value output unit 209 transmits the control value (voltage value) calculated by the control unit 200 to the motor driving device 120 via the interface unit 105.

  The processing mode input unit 204 inputs information regarding the processing mode received via the interface unit 105 to the estimation unit 210. The temperature data input unit 205 inputs the temperature data received via the interface unit 105 to the estimation unit 210.

  The estimation unit 210 includes a rotation speed estimation unit 211, a load torque estimation unit 212, a coil resistance value calculation unit 213, and a failure diagnosis unit 214, and operates in conjunction with the control of the electric motor 130 by the control unit 200.

  The rotation speed estimation unit 211 generates (or updates) a motor nominal model that is a control model for calculating an estimated value of the rotation speed of the electric motor 130 based on the control value (voltage value) output from the control unit 200. . Further, the estimated value of the rotation speed is calculated using the generated (or updated) motor nominal model.

  The load torque estimation unit 212 generates (or updates) a torque estimation model. The torque estimation model calculates an estimated value of the load torque of the electric motor 130 based on the estimated value of the rotational speed calculated based on the motor nominal model and the actual measured value of the rotational speed acquired via the control unit 200. It is a control model. The load torque estimation unit 212 calculates an estimated value of the load torque of the electric motor 130 using the generated (or updated) torque estimation model.

  The coil resistance value calculation unit 213 is based on the estimated value of the rotation speed calculated by the rotation speed estimation unit 211 and the actual measurement value of the rotation speed acquired through the control unit 200 under a predetermined condition. The variation rate of the coil resistance value of the electric motor 130 is calculated. The calculated variation rate of the coil resistance value is used to correct the motor nominal model and the torque estimation model.

  The failure diagnosis unit 214 estimates the rotational speed under a predetermined condition using a motor nominal model corrected by the variation rate of the coil resistance value derived based on the temperature data input from the temperature data input unit 205. The estimated value of the rotation speed calculated in the unit 211 is acquired. Further, based on the acquired estimated value of the rotational speed, the presence or absence of a failure in the drive system including the electric motor 130 is diagnosed.

  Hereinafter, the process in which the load torque estimation unit 212 calculates the estimated value of the load torque of the electric motor 130 is referred to as “load torque estimation process”. The process in which the coil resistance value calculation unit 213 calculates the variation rate of the coil resistance value of the electric motor 130 is referred to as “coil resistance value calculation process”. Further, the process in which the failure diagnosis unit 214 diagnoses the presence or absence of a failure in the drive system including the electric motor 130 is referred to as “failure diagnosis process”. Which of the load torque estimation process, the coil resistance value calculation process, and the failure diagnosis process is executed is determined by the estimation unit 210 based on the processing mode information input from the processing mode input unit 204. And

  The time constant deriving unit 221 refers to the approximate expression or table stored in advance based on the actual measured value of the rotational speed transmitted from the estimating unit 210, and the mechanical time constant and the electrical time constant of the electric motor 130 according to the rotational speed. Is derived. Further, the derived mechanical time constant and electrical time constant are input to the estimation unit 210. In the approximate expression or table, the relationship between the rotational speed and the mechanical time constant and electric time constant of the electric motor 130 is defined.

  The rotation speed estimation unit 211 and the load torque estimation unit 212 of the estimation unit 210 update the motor nominal model and the torque estimation model based on the mechanical time constant and the electrical time constant derived by the time constant deriving unit 221, respectively.

  The coil resistance value management unit 222 manages the fluctuation rate of the coil resistance value of the electric motor 130 calculated by the coil resistance value calculation unit 213 as a calculated value. In addition, an approximate expression or table in which the relationship between the variation rate of the coil resistance value of the electric motor 130 and the temperature is defined in advance, and the electric motor 130 is configured based on the temperature data received by the temperature data input unit 205. The fluctuation rate of the coil resistance value is derived. Further, the derived variation rate of the coil resistance value is input to the failure diagnosis unit 214 of the estimation unit 210.

  The estimated torque value output unit 206 outputs the estimated value of the load torque calculated by the load torque estimation unit 212 of the estimation unit 210. The diagnosis result output unit 207 outputs the failure diagnosis result determined by the failure diagnosis unit 214 of the estimation unit 210. The estimated value of the load torque and the failure diagnosis result are output via the interface unit 105.

<3. Explanation of processing mode>
Next, the processing mode executed in the estimation unit 210 will be described. FIG. 3 is a diagram illustrating an example of processing modes executed in the estimation unit 210. As shown in FIG. 3, the processing modes executed in the estimation unit 210 include “load torque estimation mode”, “coil resistance value calculation mode”, and “failure diagnosis mode”. In the estimation part 210, it changes to the processing mode according to the information regarding the processing mode input from the processing mode input part 204, and performs a corresponding process.

  In the load torque estimation mode, when the control unit 200 controls the electric motor 130, the rotation speed estimation unit 211 calculates an estimated value of the rotation speed using a motor nominal model, and the load torque estimation unit 212 uses the torque estimation model. In this mode, the estimated value of the load torque is calculated.

  In the coil resistance value calculation mode, when the control unit 200 controls the electric motor 130 under a predetermined condition, the rotation speed estimation unit 211 calculates an estimated value of the rotation speed using a motor nominal model, and the coil resistance value is calculated. In this mode, the value calculation unit 213 calculates the fluctuation rate of the coil resistance value. Note that the fluctuation rate of the coil resistance value calculated in the coil resistance value calculation mode is calculated when the estimated value of the rotation speed of the electric motor 130 and the estimated value of the load torque are calculated in the load torque estimation mode. Used to modify the torque estimation model.

  In the failure diagnosis mode, when the control unit 200 controls the electric motor 130 under a predetermined condition, the rotation speed estimation unit 211 calculates an estimated value of the rotation speed using a motor nominal model, and the failure diagnosis unit 214 Is a mode for diagnosing the presence or absence of a failure in the drive system including the electric motor 130.

<4. Explanation of block diagram>
Next, a block diagram for the control unit 200 to control the rotation speed or position of the electric motor and for the estimation unit 210 to estimate the rotation speed and load torque will be described. FIG. 4 is a block diagram for the control unit 200 to control the rotation speed or position of the electric motor 130 and for the estimation unit 210 to estimate the rotation speed and the load torque.

As shown in FIG. 4, in the control unit 200, the control target value (target rotational speed ω _tgt or target position x _tgt ) and the feedback actual value (rotational speed actual value ω _det or rotational position actual value x _det). ) And a control value (voltage value V _ctl ) is output.

In the electric motor 130, a predetermined rotational torque T is generated based on the control value (voltage value V _ctl ) output from the control unit 200. On the other hand, since the unknown load torque τ is applied to the electric motor 130, the electric motor 130 rotates at a rotation speed corresponding to a difference value between the rotation torque T and the load torque τ.

The position / rotation speed detection unit 140 detects the rotation speed of the electric motor 130 and feeds back the measured rotation speed value ω _det to the control unit 200.

Alternatively, the position information is calculated based on the detected rotational speed (or the position information is directly detected), and is fed back to the control unit 200 as the actual value x _det of the position information.

Thus, by performing feedback control based on the actual rotational speed value ω _det or the positional information actual value x _det , the electric motor 130 is controlled to the target rotational speed ω _tgt or the target position x _tgt. .

In parallel with the control of the rotational speed or the position of the electric motor 130, the estimation unit 210 sequentially calculates the estimated value ω _e of the rotational speed and the estimated value τ _e of the load torque.

Specifically, the rotation speed estimation unit 211 acquires a control value (voltage value V _ctl ) output from the control unit 200 and estimates the rotation speed of the electric motor 130 based on the motor nominal model P (s). The value ω _e is calculated.

In addition, the estimation unit 210 acquires the actual rotational speed value ω _det detected by the position / rotational speed detection unit 140 and calculates the difference value between the rotational speed estimation value ω _e and the actual measurement value ω _det. This is input to the load torque estimation unit 212.

The load torque estimation unit 212 calculates the estimated value τ _e of the load torque from the input difference value using the torque estimation model Tq (s).

  The torque estimation model Tq (s) can be expressed as follows.

ただし、Ｐ^−１（ｓ）は、モータノミナルモデルＰ（ｓ）の逆数である。また、Ｆ（ｓ）は、低域フィルタの伝達関数であり、Ｐ（ｓ）がｎ次の伝達関数であった場合、以下のように表すことができる。

However, P ⁻¹ (s) is the reciprocal of the motor nominal model P (s). F (s) is a transfer function of the low-pass filter, and when P (s) is an n-th order transfer function, it can be expressed as follows.

更に、Ｒは電動モータ１３０のコイル抵抗値を、Ｌは電動モータ１３０のコイルインダクタンスを、Ｋｔはトルク定数をそれぞれ表している。また、ｆは帯域周波数を表している。

Furthermore, R represents the coil resistance value of the electric motor 130, L represents the coil inductance of the electric motor 130, and Kt represents the torque constant. F represents the band frequency.

Here, a process of calculating the estimated value τ _e of the load torque by inputting the difference value between the estimated value ω _e of the rotational speed and the actually measured value ω _det to the load torque estimating unit 212 will be briefly described.

In Formula 1, first, when P ⁻¹ (s) F (s) is multiplied by the difference value between the estimated value ω _e of the rotational speed and the actually measured value ω _det, it is necessary to drive the load torque τ. estimate of the voltage (referred to as V _e in this case) is calculated.

Furthermore, the estimated value V _e of the calculated voltage, the Kakeawaseru the 1 / (R + sL), the estimated value of the current required to drive the load torque τ min (referred to as I _e in this case) is calculated. The estimated value τ _e corresponding to the load torque τ can be calculated by multiplying the calculated current estimated value I _e by the torque constant Kt.

From the above, the estimated value τ _e of the load torque is calculated by multiplying the difference value between the estimated value ω _e of the rotational speed and the measured value ω _det by the torque estimation model Tq (s) shown in Equation 1. Can do.

Note that the control value (voltage value V _ctl ) and the actual measurement value (actual rotational speed measurement value ω _det ) are output for each control cycle of the control unit 200, and therefore the estimation unit 210 performs the control unit 200 for each control cycle. The estimated value τ _e of the load torque can be calculated.

<5. Motor nominal model>
Next, details of the motor nominal model P (s) will be described. In general, an electric motor can be expressed by a block diagram shown in FIG.

5A, V _ctl is a control value (voltage value) output from the control unit 200, R is a coil resistance value of the electric motor 130, L is a coil inductance of the electric motor 130, and Kt represents a torque constant. J represents inertia and Ke represents the back electromotive force constant.

  Here, the closed loop block diagram shown in FIG. 5A can be rewritten to the open loop block diagram shown in FIG.

  That is, the motor nominal model P (s) can be expressed as follows.

なお、Ｔｍは機械時定数であり、下式により表すことができる。

Tm is a mechanical time constant and can be expressed by the following equation.

ただし、Ｊはイナーシャを、Ｋｔはトルク定数を、Ｋｅは逆起電力定数をそれぞれ示している。

Here, J represents inertia, Kt represents a torque constant, and Ke represents a back electromotive force constant.

  Te is an electrical time constant and can be expressed by the following equation.

ただし、Ｌは電動モータ１３０のコイルインダクタンスを、Ｒは電動モータ１３０のコイル抵抗値をそれぞれ表している。

However, L represents the coil inductance of the electric motor 130, and R represents the coil resistance value of the electric motor 130.

As described above, the motor nominal model P (s) (and the torque estimation model) necessary for obtaining the estimated value τ _e of the load torque includes the mechanical time constant and the electrical time constant.

  Here, the applicant of the present application analyzed the cause of the increase in the error of the estimated value of the load torque calculated using the prior art with a change in the state of the electric motor being controlled. We paid attention to the relationship between the rotational speed of the motor and the mechanical and electrical time constants.

  When calculating the estimated value of load torque using the conventional technology, it is assumed that the mechanical time constant and electric time constant of the electric motor are always constant, and the electric motor mechanical time constant and electric time are constant regardless of the rotational speed. This is because a predetermined constant is substituted for the time constant.

  In contrast, when the applicant of the present application experimentally obtained the mechanical time constant and the electric time constant of the electric motor at various rotational speeds, the mechanical time constant and the electric time constant of the electric motor varied depending on the rotational speed. I found out that Furthermore, it was found that the mechanical time constant and the electric time constant also fluctuate because the coil resistance value of the electric motor fluctuates due to temperature fluctuations even at the same rotation speed.

  Therefore, in the following, first, the relationship between the rotational speed of the electric motor, the mechanical time constant, and the electric time constant will be described. Then, a load torque estimation process will be described in which the relationship between the rotational speed of the electric motor, the mechanical time constant, and the electrical time constant is reflected, and further, the correction according to the temperature variation is performed. Furthermore, a coil resistance value calculation process, which is a process for calculating the fluctuation rate of the coil resistance value of the electric motor caused by the temperature fluctuation, will be described. Further, a failure diagnosis process using a motor nominal model in which the mechanical time constant and the electrical time constant are corrected in accordance with temperature fluctuations will be described.

<6. Relationship between electric motor rotation speed, mechanical time constant and electrical time constant>
First, the relationship between the rotational speed ω _det of the electric motor 130, the mechanical time constant Tm, and the electric time constant Te will be described with reference to FIGS. 6 to 8.

FIG. 6 is a diagram showing how the relationship between the rotational speed ω _det of the electric motor 130 and the mechanical time constant Tm is experimentally obtained. In FIG. 6, (a-1) shows a state in which the voltage V ₅₀₀ is step-inputted so that the rotation speed becomes 500 rpm. Further, (b-1) shows a time change of the actual measured value ω _det of the rotational speed of the electric motor 130 when the voltage V ₅₀₀ is step-inputted to the electric motor 130.

In FIG. 6B-1, the mechanical time constant Tm ₅₀₀ when the rotational speed is 500 rpm is derived by obtaining the time until the actual rotational speed value ω _det reaches 63.2% of the displacement amount. be able to.

Similarly, (a-2) shows a state in which the voltage _V1000 is step-inputted so that the rotation speed is 1000 rpm. Further, (b-2) shows the time change of the actual measured value ω _det of the rotational speed of the electric motor 130 when the voltage V ₁₀₀₀ is step-inputted to the electric motor 130.

In FIG. 6B-2, the mechanical time constant Tm ₁₀₀₀ when the rotational speed is 1000 rpm is derived by obtaining the time until the actual rotational speed value ω _det reaches 63.2% of the displacement amount. be able to.

Similarly, (a-3) shows a state in which the voltage V ₃₀₀₀ is step-inputted so that the rotation speed becomes 3000 rpm. Further, (b-3) shows the time change of the actual measured value ω _det of the rotational speed of the electric motor 130 when the voltage V ₃₀₀₀ is step-inputted to the electric motor 130.

In FIG. 6B-3, the mechanical time constant Tm ₃₀₀₀ at the rotational speed of 3000 rpm is derived by obtaining the time required for the actual rotational speed value ω _det to reach 63.2% of the displacement. Can do.

  Tm in FIG. 8 is a graph of the mechanical time constant at each rotational speed obtained in this way. In FIG. 8, the horizontal axis represents the rotational speed of the electric motor 130, and the vertical axis represents the normalized value of each mechanical time constant.

On the other hand, FIG. 7 is a diagram showing how the relationship between the rotational speed ω _det of the electric motor 130 and the electric time constant Te is experimentally obtained. In FIG. 7, (a-1) shows a state where the voltage V ₅₀₀ is step-inputted so that the rotation speed becomes 500 rpm. Further, (b-1) shows the time change of the actual measurement value I _det of the current flowing in the coil of the electric motor 130 when the voltage V ₅₀₀ is step-inputted to the electric motor 130.

In FIG. 7B-1, the electric time constant Te ₅₀₀ when the rotational speed is 500 rpm is derived by obtaining the time until the measured current value I _det reaches 63.2% of the displacement amount. Can do.

Similarly, FIG. 7A-2 shows a state in which the voltage _V1000 is step-inputted so that the rotation speed becomes 1000 rpm. FIG. 7B-2 shows the time change of the actual measurement value I _det of the current flowing in the coil of the electric motor 130 when the voltage V ₁₀₀₀ is step-inputted to the electric motor 130.

In FIG. 7B-2, the electric time constant Te ₁₀₀₀ when the rotational speed is 1000 rpm is derived by obtaining the time until the actual measured value I _det reaches 63.2% of the displacement. Can do.

Similarly, FIG. 7A-3 shows a state in which the voltage V ₃₀₀₀ is step-inputted so that the rotation speed becomes 3000 rpm. FIG. 7B-3 shows the change over time of the actual measured value I _det of the current flowing in the coil of the electric motor 130 when the voltage V ₃₀₀₀ is step-inputted to the electric motor 130.

In FIG. 7B-3, the electric time constant at the rotational speed of 3000 rpm is derived from Te ₃₀₀₀ by obtaining the time until the actual measured value I _det reaches 63.2% of the displacement. Can do.

  Te in FIG. 8 is a graph of the electrical time constant at each rotational speed determined in this way. In FIG. 8, the horizontal axis represents the rotation speed of the electric motor 130, and the vertical axis represents the normalized value of each electric time constant.

As described above, the mechanical time constant Tm and the electric time constant Te of the electric motor 130 vary according to the rotation speed. For this reason, in calculating the estimated value ω _e of the rotational speed using the motor nominal model P (s), the control device 100 according to the measured value (ω _det ) of the rotational speed of the electric motor 130 at the time of calculation, The mechanical time constant Tm and the electrical time constant Te are sequentially updated.

Specifically, based on the graph of FIG. 8, each of Tm and Te is approximated by an Nth order equation as a function of the rotational speed, and an actual value of the rotational speed of the electric motor 130 at the time of calculation is approximated to the approximate expression. By substituting (ω _det ), the mechanical time constant Tm and the electrical time constant Te are calculated. Then, the motor nominal model P (s) is generated (or updated) using the calculated mechanical time constant Tm and the electric time constant Te, and the rotation speed of the motor nominal model P (s) is generated (or updated) by the generated (or updated) motor nominal model P (s). The estimated value ω _e is calculated.

  Note that the mechanical time constant Tm and the electrical time constant Te can be expressed as follows, for example, by a linear expression.

Tm = Am × ω _det + Bm (Am and Bm are constants)
Te = Ae × ω _det + Be (Ae and Be are constants)
However, it goes without saying that the approximate expression is not limited to a linear expression.

The method for deriving the mechanical time constant Tm and the electrical time constant Te is not limited to the approximate expression. For example, a table of the graph of FIG. 8 is prepared in advance, and the mechanical time constant Tm and the electrical time constant Te corresponding to the rotation speed closest to the actual measurement value ω _det of the rotation speed of the electric motor 130 are calculated at the time of calculation. You may comprise so that it may derive | lead-out from the said table.

  In addition, although the said approximate expression or table is supposed to produce based on FIG. 8 described about the mechanical time constant and electrical time constant from 0 rpm to 3000 rpm, this invention is not limited to this. For example, an approximate expression or a table may be created using results obtained by conducting an experiment over a wider range. The created approximate expression or table is stored in the time constant deriving unit 221.

<7. Load torque estimation processing>
Next, the flow of the load torque estimation process that reflects the relationship between the rotational speed of the electric motor, the mechanical time constant, and the electrical time constant, and that has been corrected in accordance with temperature fluctuations will be described. FIG. 9 is a flowchart showing the flow of the load torque estimation process.

  When the operation instruction input unit 203 receives an operation start instruction and the processing mode input unit 204 receives “load torque estimation mode” as information regarding the processing mode, the estimation unit 210 executes a load torque estimation process.

In step S <b> 901, the load torque estimation unit 212 obtains a calculated value (coil resistance value variation rate R _t ) currently managed by the coil resistance value management unit 222. Coil resistance value calculation for calculating the fluctuation rate of the coil resistance value (the fluctuation rate R _t of the coil resistance value of the electric motor caused by the temperature fluctuation) managed by the coil resistance value management unit 222. Details of the processing will be described later.

In step S902, the estimation unit 210 acquires the control value (voltage value V _ctl1 ) output by the control unit 200 at timing T1. In addition, the actual measurement value input unit 208 acquires the actual measurement value ω _det1 of the rotational speed received at the timing T1.

In step S903, the time constant deriving unit 221 derives the mechanical time constant and the electric time constant corresponding to the actual rotational speed value ω _det1 acquired in step S902 based on the approximate expression stored in the time constant deriving unit 221. To do. Here, the mechanical time constant Tm_ω _det1 and the electrical time constant Te_ω _det1 are derived.

In step S904, the rotation speed estimation unit 211 generates a motor nominal model P (s) ₁ based on the mechanical time constant Tm_ω _det1 and the electric time constant Te_ω _det1 . Furthermore, the load torque estimation unit 212 generates a torque estimation model Tq (s) ₁ based on the mechanical time constant Tm_ω _det1 and the electric time constant Te_ω _det1 . At this time, the rotational speed estimating unit 211 and the load torque estimating unit 212 use the motor correction model R (t) ₁ and the torque estimation model according to the predetermined correction contents using the variation rate R _t of the coil resistance value acquired in step S901. Tq (s) ₁ is corrected. Specifically, based on Equation 4, the derived mechanical time constant Tm_omega _det1 By Kakeawaseru the variation rate _{R t} of the coil resistance, modify the mechanical time constant Tm_ω _det1. Further, the electrical time constant Te_ω _det1 is corrected by dividing the derived electrical time constant Te_ω _det1 by the variation rate R _t of the coil resistance value based on Expression 5. Furthermore, in the torque estimation model Tq (s) _1, based on Equation 1 is modified by Kakeawaseru the variation rate R _t of the coil resistance value in the denominator of R (coil resistance) (R → R × _Rt ).

In step S905, the rotational speed estimation unit 211 multiplies the motor nominal model P (s) ₁ generated in step S904 by the control value (voltage value V _ctl1 ) acquired in step S902, thereby estimating the rotational speed. The value ω _e1 is calculated.

In step S906, the estimation unit 210 calculates a difference value between the actually measured rotational speed value ω _det1 acquired in step S902 and the estimated rotational speed value ω _e1 calculated in step S905.

Further, the load torque estimation unit 212 calculates the estimated value τ _e1 of the load torque by multiplying the torque estimation model Tq (s) ₁ generated and corrected in step S904 by the difference value.

When the calculation of the estimated value τ _e1 of the load torque is completed in step S906, the process proceeds to step S907. In step S907, the estimation unit 210 determines whether or not to end the load torque estimation process. The estimation unit 210 determines to end the load torque estimation process when the operation instruction input unit 203 receives an operation stop instruction. On the other hand, when the operation instruction input unit 203 has not received an operation stop instruction, it is determined to maintain the load torque estimation process.

  If it is determined in step S907 that the estimation unit 210 maintains the load torque estimation process, the process waits until the next control period, and executes the processes from step S902 again in the next control period.

That is, the control value V _ctl2 and the actual measured value ω _det2 of the rotational speed are acquired at the timing T2 (step S902), and the mechanical time constant Tm_ω _det2 and the electrical time constant Te_ω _det2 are derived (step S903). Further, the motor nominal model P (s) ₂ and the torque estimation model Tq (s) ₂ are updated with the derived mechanical time constant Tm_ω _det2 and the electrical time constant Te_ω _{det 2,} and the fluctuation rate R _t of the coil resistance value is used. Correction is made (step S904). Further, an estimated value ω _e2 of the rotational speed is calculated (step S905), and an estimated value τ _e2 of the load torque is calculated (step S906).

  Thereafter, similar processing is repeated in the next control cycle. Thus, in each control cycle, the motor nominal model and the torque estimation model are updated with the mechanical time constant and the electric time constant corresponding to the actual measured value of the rotation speed, and corrected using the fluctuation rate of the coil resistance value. Then, an estimated value of the load torque is calculated. As a result, the estimated value of the load torque can be accurately calculated regardless of the rotational speed of the electric motor and the ambient temperature of the electric motor.

<8. Coil resistance value calculation process>
Then, for calculating the variation rate R _t of the coil resistance value of the electric motor 130 which occur due to variations in temperature, the flow of coil resistance value calculation processing will be described. FIG. 10 is a flowchart showing the flow of the coil resistance value calculation process.

  In a state where a predetermined condition (load torque τ = 0) is satisfied, the operation instruction input unit 203 receives an operation start instruction, and the target rotational speed input unit 201 or the target position input unit 202 sets a predetermined target rotational speed or target position. When receiving, the control unit 200 starts control of the electric motor 130. At this time, when the processing mode input unit 204 receives the “coil resistance value calculation mode” as information regarding the processing mode, the estimation unit 210 executes a coil resistance value calculation process.

In step S1001, the coil resistance value calculation unit 213 substitutes 1.0 as the variation rate of the coil resistance value. In step S1002, the estimation unit 210 acquires the control value (voltage value V _ctl1 ) output by the control unit 200 at the timing T1. Further, the estimation unit 210 acquires the actual measured value ω _det1 of the rotational speed received by the actual value input unit 208 at the timing T1.

In step S _<b> 1003, the time constant deriving unit 221 derives the mechanical time constant and the electrical time constant corresponding to the measured rotational speed value ω _det1 based on the approximate expression stored in the time constant deriving unit 221. Here, the mechanical time constant Tm_ω _det1 and the electrical time constant Te_ω _det1 are derived.

In step S1004, the rotation speed estimation unit 211 generates a motor nominal model P (s) ₁ based on the mechanical time constant Tm_ω _det1 and the electric time constant Te_ω _det1 . At this time, the rotational speed estimation unit 211 corrects the motor nominal model P (s) _{1 based} on the correction content using the variation rate of the coil resistance value. Specifically, based on Equation 4, the derived mechanical time constant Tm_omega _det1 the fluctuation rate of the coil resistance value (in this case 1.0) By Kakeawaseru and modifies the mechanical time constant Tm_ω _det1. Further, the electrical time constant Te_ω _det1 is corrected by dividing the derived electrical time constant Te_ω _det1 by the fluctuation rate of the coil resistance value (here, 1.0) based on the equation (5).

In step S1005, the rotation speed estimation unit 211 calculates an estimated value ω _e1 of the rotation speed. Specifically, by multiplying the motor nominal model P (s) ₁ generated and corrected in step S1004 by the control value (voltage value _Vct11 ) acquired in step S1002, the estimated rotational speed value ω _e1. Is calculated.

  In step S1006, the coil resistance value calculation unit 213 changes the variation rate of the coil resistance value by executing a coil resistance value determination process (1.0 → R ′ (R ′ is 1.1, for example)). . Details of the coil resistance value determination process in step S1006 will be described later.

  In step S1007, it is determined whether or not the coil resistance value variation rate has been determined by the coil resistance value calculation unit 213. If it is determined in step S1007 that the variation rate of the coil resistance value has not been determined, the process waits until the next control cycle, and the processing from step S1002 is executed again in the next control cycle.

That is, the control value V _ctl2 and the actual measured value ω _det2 of the rotational speed are acquired at the timing T2 (step S1002), and the mechanical time constant Tm_ω _det2 and the electric time constant Te_ω _det2 are derived (step S1003). Further, the motor nominal model P (s) ₂ is updated with the derived mechanical time constant Tm_ω _det2 and electrical time constant Te_ω _{det 2} , and then the fluctuation rate (R ′) of the coil resistance value calculated in step S1006 is used. Correction is made (step S1004). Further, an estimated value ω _e2 of the rotation speed is calculated (step S1005), and a coil resistance value determination process is executed (step S1006). Hereinafter, in the coil resistance value determination process, the variation rate of the coil resistance value is changed until the variation rate of the coil resistance value is determined (R ′ → R ″ → R ′ ″... R _t ). Repeat the process. Note that the example of FIG. 10 indicates that the variation rate of the coil resistance value is determined as _Rt .

<9. Coil resistance value determination process>
Next, a detailed flow of the coil resistance value determination process (step S1006 in FIG. 10) for determining the variation rate of the coil resistance value will be described. FIG. 11 is a flowchart showing the flow of the coil resistance value determination process.

In step S < _b > 1101, the coil resistance value calculation unit 213 acquires the rotation speed estimation value ω _e calculated by the rotation speed estimation unit 211. In step S1102, the coil resistance value calculation unit 213 compares the measured rotational speed value ω _det acquired by the estimation unit 210 with the estimated rotational speed value ω _e and determines whether or not they are substantially equal (difference between the two). It is determined whether or not the value is within a predetermined range.

If it is determined in step S1102 that the difference value between the estimated value ω _e of the rotational speed and the measured value ω _det of the rotational speed is not within the predetermined range, the process proceeds to step S1103. In step S1103, the coil resistance value calculation unit 213 determines whether or not the estimated rotational speed value ω _e is greater than the actual measured rotational speed value ω _det . If it is determined in step S1103 that the estimated rotational speed value ω _e is greater than the actually measured rotational speed value ω _det , the process proceeds to step S1104.

  In step S1104, the coil resistance value calculation unit 213 increases the variation rate of the coil resistance value. For example, the variation rate of the coil resistance value is changed from 1.0 to 1.1. Thereby, in step S1004 (FIG. 10) of the next control cycle, the mechanical time constant and the electrical time constant are corrected (the mechanical time constant becomes 1.1 times, and the electrical time constant becomes 1 / 1.1 times). Become).

On the other hand, if it is determined in step S1103 that the estimated rotational speed value ω _e is smaller than the actually measured rotational speed value ω _det , the process proceeds to step S1105. In step S1105, the coil resistance value calculation unit 213 decreases the variation rate of the coil resistance value. For example, the variation rate of the coil resistance value is changed from 1.0 to 0.9. As a result, the mechanical time constant and the electrical time constant are corrected (the mechanical time constant is 0.9 times and the electrical time constant is 1 / 0.9 times).

On the other hand, if it is determined in step S1102 that the estimated rotational speed value ω _e is substantially equal to the actually measured rotational speed value ω _det (the difference between the two is within a predetermined range), the process proceeds to step S1106. In step S <b> 1106, the coil resistance value calculation unit 213 stores the fluctuation rate of the coil resistance value at this time in the coil resistance value management unit 222.

Thus, in the control device 100 according to the present embodiment,
A predetermined condition (load torque τ = 0) is satisfied, and
・ The motor nominal model has been updated with the mechanical time constant and electrical time constant corresponding to the rotation speed of the electric motor.
In the state, the difference value generated between the estimated rotational speed value calculated using the motor nominal model and the measured rotational speed value is caused by the fluctuation of the coil resistance value caused by the temperature fluctuation. It was set as the structure judged to be.

  This makes it possible to eliminate the effect of temperature fluctuations by changing the coil resistance value fluctuation rate so that the difference value between the estimated rotational speed value and the measured rotational speed value is within a predetermined range. Become.

<10. Fault diagnosis processing>
Next, a flow of failure diagnosis processing executed in the estimation unit 210 will be described. FIG. 12 is a flowchart showing the flow of the failure diagnosis process.

  In a state where a predetermined condition (load torque τ = 0) is satisfied, the operation instruction input unit 203 receives an operation start instruction, and the target rotational speed input unit 201 or the target position input unit 202 sets a predetermined target rotational speed or target position. When receiving, the control unit 200 starts control of the electric motor 130. At this time, when the processing mode input unit 204 receives “fault diagnosis mode” as information regarding the processing mode, the estimation unit 210 executes a fault diagnosis process.

In step S1201, the temperature data input unit 205 receives the temperature data theta ₁ at timing T1. In addition, the estimation unit 210 acquires the temperature data θ ₁ received by the temperature data input unit 205.

In step S1202, the coil resistance value management unit 222 corresponds to the temperature data theta ₁ obtained in the estimation unit 210 derives the rate of change in coil resistance. Here, it derives the variation rate R ₁ of the coil resistance.

FIG. 13 is a diagram illustrating an example of a table stored in the coil resistance value management unit 222. As shown in FIG. 13, the coil resistance value management unit 222 stores a variation rate of the coil resistance value experimentally obtained in advance in association with each temperature data. Thereby, the coil resistance value management unit 222 can derive the fluctuation rate R ₁ of the coil resistance value corresponding to the temperature data θ ₁ acquired by the estimation unit 210.

Returning to the description of FIG. In step S1203, the estimation unit 210 acquires the control value (voltage value V _ctl1 ) output by the control unit 200 at the timing T1. Further, the actual measurement value input unit 208 acquires the actual measurement value ω _det1 of the rotational speed received at the timing T1.

In step _{S <b> 1204} , the time constant deriving unit 221 derives the mechanical time constant and the electrical time constant corresponding to the measured rotational speed value ω _det1 based on the approximate expression stored in the time constant deriving unit 221. Here, the mechanical time constant Tm_ω _det1 and the electrical time constant Te_ω _det1 are derived.

In step S1205, the rotational speed estimation unit 211 generates a motor nominal model P (s) ₁ based on the mechanical time constant Tm_ω _det1 and the electric time constant Te_ω _det1 . At this time, the rotational speed estimation unit 211 corrects the motor nominal model P (s) _{1 based} on the correction content using the coil resistance value variation rate R ₁ . Specifically, based on Equation 4, the derived mechanical time constant Tm_omega _det1 By Kakeawaseru the variation rate _{R 1} of the coil resistance value, to correct the mechanical time constant Tm_ω _det1. Further, the electrical time constant Te_ω _det1 is corrected by dividing the derived electrical time constant Te_ω _det1 by the variation rate R ₁ of the coil resistance value based on Expression 5.

In step S1206, the rotation speed estimation unit 211 calculates an estimated value ω _e1 of the rotation speed. Specifically, the motor nominal model P (s) ₁ generated and corrected in step _S1205 is multiplied by the control value (voltage value V _ctl1 ) acquired in step S1203 to obtain the estimated rotational speed value ω _e1 . calculate.

In step S1207, the failure diagnosis unit 214 compares the estimated rotational speed value ω _e1 calculated in step S1206 with the actual measured rotational speed value ω _det1 acquired in step S1203. As a result of the comparison, when it is determined that the estimated value ω _e1 of the rotational speed calculated in step S1206 is not equal to the actual measured value ω _det1 of the rotational speed acquired in step S1203 (the difference value between them is outside the predetermined range). In step S1208, the process proceeds to step S1208.

In step S1208, the failure diagnosis unit 214 determines that the drive system including the electric motor 130 has failed, and outputs a failure diagnosis result (including an alarm) via the diagnosis result output unit 207. On the other hand, as a result of the comparison, it is determined that the estimated rotational speed value ω _e1 calculated in step S1206 is substantially equal to the measured rotational speed value ω _det1 acquired in step S1203 (the difference value between the two is within a predetermined range). If so, the process proceeds to step S1209. In step S1209, the failure diagnosis unit 214 determines that the drive system including the electric motor 130 is normal (no failure), and outputs the failure diagnosis result via the diagnosis result output unit 207.

Thus, in the control device 100 according to the present embodiment,
・ The predetermined condition (load torque τ = 0) is satisfied,
-The motor nominal model is updated with the mechanical time constant and electrical time constant corresponding to the rotation speed of the electric motor, and
-The motor nominal model has been corrected using the rate of variation of the coil resistance value according to the temperature data.
In the state, the difference value generated between the estimated value of the rotational speed calculated using the motor nominal model and the measured value of the rotational speed is determined to be caused by the failure of the electric motor. Thereby, it becomes possible to perform failure diagnosis of the drive system including the electric motor 130.

<11. Summary>
As is clear from the above description, in the control device according to the present embodiment,
-The motor nominal model of the electric motor to be controlled and the torque estimation model for estimating the load torque related to the electric motor were identified. Also, a configuration for estimating the load torque of the electric motor by using the identified motor nominal model and torque estimation model using the control value (voltage value) for controlling the electric motor and the actual measured value of the rotational speed of the electric motor. It was.
-In identifying the motor nominal model and the torque estimation model, we focused on the fact that the mechanical time constant and the electric time constant fluctuate according to the rotation speed of the electric motor. Further, the inventors have focused on the point that the coil resistance value included in the mechanical time constant and the electrical time constant varies depending on the temperature. Then, a mechanical time constant and an electrical time constant based on the measured value of the rotational speed are derived, and a motor nominal model and a torque estimation model are generated, and then the model is corrected based on the variation rate of the coil resistance value.
The mechanical time constant and the electrical time constant at each rotation speed are experimentally obtained in advance and approximated by an n-th order approximate expression or stored in a table.
・ The fluctuation rate of the coil resistance value according to the temperature is an estimation of the rotational speed calculated in the motor nominal model updated with the mechanical time constant and the electrical time constant according to the actual rotational speed value under the predetermined condition. The value is changed so that the value is substantially equal to the actually measured rotational speed.
-It was set as the structure which calculated | required experimentally the fluctuation rate of the coil resistance value according to temperature beforehand. In addition, rotation is performed using a motor nominal model that is updated with mechanical time constants and electrical time constants according to measured rotational speed values, and corrected with the rate of change in coil resistance values according to temperature, under predetermined conditions. The estimated speed value is calculated. Then, when the calculated estimated value of the rotational speed is different from the actual measured value of the rotational speed, the drive system including the electric motor is determined to have failed.

  As a result, it is possible to avoid the conventional problem that the error of the estimated value of the load torque increases due to fluctuations in the rotational speed and temperature of the electric motor. As a result, it is possible to improve the estimation accuracy of the load torque of the electric motor.

[Second Embodiment]
In the first embodiment, the rotation speed, the mechanical time constant, and the electrical time constant of the electric motor 130 to be controlled are assumed as the case where the identified control model fluctuates due to a change in the state of the electric motor 130 to be controlled. And the relationship between temperature and coil resistance.

  However, the change in the state of the electric motor that is the control target can be grasped as a variation in the rotational speed, and can be also regarded as a variation in the load torque, for example.

  Therefore, in this embodiment, first, the relationship between the load torque of the electric motor, the mechanical time constant, and the electrical time constant will be described. Then, a load torque estimation process will be described in which the relationship between the load torque of the electric motor, the mechanical time constant, and the electrical time constant is reflected and the correction accompanying the change in temperature is performed.

  Note that the hardware configuration (FIG. 1), functional configuration (FIG. 2), processing mode (FIG. 3), block diagram (FIG. 4), and motor nominal model (FIG. 5) of the control device in this embodiment are described above. Since it is the same as 1st Embodiment, description is abbreviate | omitted here.

<1. Relationship between load torque of electric motor, mechanical time constant and electric time constant>
First, the relationship between the load torque τ of the electric motor 130, the mechanical time constant Tm, and the electric time constant Te will be described with reference to FIGS.

FIG. 14 is a diagram showing how the relationship between the load torque τ of the electric motor 130 and the mechanical time constant Tm is experimentally obtained. In FIG. 14, (a-1) is stepwise input with the voltage V ₁ so as to obtain a predetermined rotational speed in a state where the known load torque τ = 0.01 [Nm] is applied to the electric motor 130. It shows a state. The (b-1) is the electric motor 130 while the known load torque τ = 0.01 [Nm] is applied as in the case where the voltages _{V 1} and step input to the electric motor 130, the electric motor 130 The time change of the actual measurement value ω _det of the rotation speed is shown.

In FIG. 14 (b-1), the time when the measured value ω _det of the rotational speed reaches 63.2% of the displacement is obtained, whereby the machine when the load torque τ = 0.01 [Nm]. A time constant Tm ₁ can be derived.

Similarly, FIG. 14 (a-2) is in a state of the known load torque τ = 0.02 [Nm] is applied as the electric motor 130, to a predetermined rotational speed, the step voltage _{V 2} It shows how it was entered. Further, FIG. 14 (b-2) is the electric motor 130 while the known load torque τ = 0.02 [Nm] is applied as in the case where the voltage _{V 2} and the step input to the electric motor 130, the electric The time change of the actual measurement value ω _det of the rotation speed of the motor 130 is shown.

In FIG. 14 (b-2), by obtaining the time until the measured value ω _det of the rotational speed reaches 63.2% of the displacement, the machine when the load torque τ = 0.02 [Nm] is obtained. A time constant Tm ₂ can be derived.

Similarly, FIG. 14 (a-3) is a state in which the known load torque τ = 0.06 [Nm] is applied as the electric motor 130, to a predetermined rotational speed, the step voltage _{V 6} It shows how it was entered. Further, FIG. 14 (b-3) is the electric motor 130 while the known load torque τ = 0.06 [Nm] is applied as in the case where the voltage _{V 6} and step input to the electric motor 130, the electric The time change of the actual measurement value ω _det of the rotation speed of the motor 130 is shown.

In FIG. 14 (b-3), the time when the measured value ω _det of the rotational speed reaches 63.2% of the displacement is obtained, whereby the machine when the load torque τ = 0.06 [Nm]. A time constant Tm ₆ can be derived.

  Tm in FIG. 16 is a graph of the mechanical time constant at each rotational speed obtained in this way. In FIG. 16, the horizontal axis indicates a known load torque applied to the electric motor 130, and the vertical axis indicates a value obtained by normalizing each mechanical time constant.

On the other hand, FIG. 15 is a diagram showing a state in which the relationship between the load torque τ of the electric motor 130 and the electric time constant Te is obtained experimentally. In FIG. 15, (a-1) step-inputs the voltage V ₁ so as to obtain a predetermined rotational speed in a state where a known load torque τ = 0.01 [Nm] is applied to the electric motor 130. It shows a state. The (b-1) is the electric motor 130 while the known load torque τ = 0.01 [Nm] is applied as in the case where the voltages _{V 1} and step input to the electric motor 130, the electric motor 130 The time change of the measured value I _det of the current flowing through the coil is shown.

In FIG. 15 (b-1), the electric time when load torque τ = 0.01 [Nm] is obtained by obtaining the time until the measured current value I _det reaches 63.2% of the displacement amount. A constant Te ₁ can be derived.

Similarly, FIG. 15 (a-2) is in a state of the known load torque τ = 0.02 [Nm] is applied as the electric motor 130, to a predetermined rotational speed, the step voltage _{V 2} It shows how it was entered. Further, FIG. 15 (b-2) is the electric motor 130 while the known load torque τ = 0.02 [Nm] is applied as in the case where the voltage _{V 2} and the step input to the electric motor 130, the electric The time change of the actual measurement value I _det of the current flowing in the coil of the motor 130 is shown.

In FIG. 15 (b-2), the electric time when the load torque τ = 0.02 [Nm] is obtained by obtaining the time until the measured current value I _det reaches 63.2% of the displacement amount. A constant Te ₂ can be derived.

Similarly, FIG. 15A-3 shows the step of setting the voltage V ₆ so that the electric motor 130 is applied with a known load torque τ = 0.06 [Nm] so that the predetermined rotational speed is obtained. It shows how it was entered. FIG. 15B-3 shows the electric motor when the voltage V ₆ is step-inputted to the electric motor 130 in a state where the known load torque τ = 0.06 [Nm] is applied to the electric motor 130. The time change of the actual measurement value I _det of the current flowing in the coil of the motor 130 is shown.

As shown in FIG. 15 (b-3), when the load torque τ = 0.06 [Nm] is obtained by obtaining the time until the measured current value I _det reaches 63.2% of the displacement amount. The electrical time constant of Te ₆ can be derived.

  Te in FIG. 16 is a graph of the electrical time constant at each rotational speed obtained in this way. In FIG. 16, the horizontal axis indicates a known load torque applied to the electric motor 130, and the vertical axis indicates a value obtained by normalizing each electrical time constant.

As described above, the mechanical time constant Tm and the electric time constant Te of the electric motor 130 vary according to the load torque. For this reason, in calculating the estimated value ω _e of the rotational speed using the motor nominal model P (s), the control device 100 determines the mechanical time constant according to the estimated value of the load torque of the electric motor 130 at the previous calculation. Tm and electric time constant Te were sequentially updated.

Specifically, based on the graph of FIG. 16, Tm and Te are approximated by an Nth order equation as a function of the load torque, and the load torque of the electric motor 130 at the time of the previous calculation is estimated by the approximate equation. By substituting the values, the mechanical time constant Tm and the electrical time constant Te are calculated. Then, the motor nominal model P (s) is generated (or updated) using the calculated mechanical time constant Tm and the electric time constant Te, and the rotation speed of the motor nominal model P (s) is generated (or updated) by the generated (or updated) motor nominal model P (s). The estimated value ω _e is calculated.

  Note that the mechanical time constant Tm and the electrical time constant Te can be expressed as follows, for example, by a linear expression.

Tm = Cm × τ _e + Dm (Cm and Dm are constants)
Te = Ce × τ _e + De (Ce and De are constants)
However, it goes without saying that the approximate expression is not limited to a linear expression.

  The method for deriving the mechanical time constant Tm and the electrical time constant Te is not limited to the approximate expression. For example, a table of the graph of FIG. 16 is prepared in advance, and the mechanical time constant Tm and the electrical time constant Te corresponding to the load torque closest to the estimated value τe of the load torque of the electric motor 130 are calculated at the time of calculation. You may comprise so that it may derive | lead-out from a table.

  The approximate expression or table is created based on FIG. 16 describing the mechanical time constant and the electric time constant when the load torque is 0 [Nm] to 0.06 [Nm]. It is not limited to this. For example, an approximate expression or a table may be created using results obtained by conducting an experiment over a wider range. The created approximate expression or table is stored in the time constant deriving unit 221.

<2. Load torque estimation processing>
Next, the flow of the load torque estimation process that reflects the relationship between the load torque of the electric motor, the mechanical time constant, and the electrical time constant, and that has been corrected in accordance with temperature fluctuations will be described. FIG. 17 is a flowchart showing the flow of the load torque estimation process.

  When the operation instruction input unit 203 receives an operation start instruction and the processing mode input unit 204 receives “load torque estimation mode” as information regarding the processing mode, the estimation unit 210 executes a load torque estimation process.

In step S <b> 1701, the load torque estimation unit 212 obtains the calculated value (coil resistance value variation rate R _t calculated by the coil resistance value calculation unit 213) currently managed by the coil resistance value management unit 222.

In step S1702, the estimation unit 210 acquires the control value (voltage value V _ctl1 ) output by the control unit 200 at the timing T1. Further, the actual measurement value input unit 208 acquires the actual measurement value ω _det1 of the rotational speed received at the timing T1.

In step S1703, the load torque estimation unit 212 acquires the estimated value of the previous load torque. Here, since there is no estimated value of the previous load torque, a predetermined initial value τ _e0 is acquired.

In step S1704, the time constant deriving unit 221 stores in the time constant deriving unit 221 the mechanical time constant and the electric time constant corresponding to the estimated value of the load torque (here, the initial value τ _e0 ) acquired in step S1703. Derived based on the approximate expression. Here, a mechanical time constant Tm_τ _e0 and an electric time constant Te_τ _e0 are derived.

In step S1705, the rotation speed estimation unit 211 generates a motor nominal model P (s) ₁ based on the mechanical time constant Tm_τ _e0 and the electric time constant Te_τ _e0 . Further, the load torque estimation unit 212 generates a torque estimation model Tq (s) ₁ based on the mechanical time constant Tm_τ _e0 and the electric time constant Te_τ _e0 . At this time, the rotational speed estimation unit 211 and the load torque estimation unit 212 correct the motor nominal model P (s) ₁ and the torque estimation model Tq (s) _{1 according} to the correction content using the variation rate of the coil resistance value. Specifically, the mechanical time constant Tm_τ _e0 is corrected by multiplying the derived mechanical time constant Tm_τ _e0 by the variation rate R _t of the coil resistance value based on Expression 4. Further, the electrical time constant Te_τ _e0 is corrected by dividing the derived electrical time constant Te_τ _e0 by the variation rate R _t of the coil resistance value based on Equation 5. Further, in the torque estimation model Tq (s) ₁ , the denominator R (coil resistance value) is corrected based on Equation 1 (R → R × R _t ).

In step S1706, the rotation speed estimation unit 211 calculates an estimated value ω _e1 of the rotation speed. Specifically, by multiplying the motor nominal model P (s) ₁ generated and corrected in step S1705 by the control value (voltage value _Vct11 ) acquired in step S1702, the estimated rotational speed value ω _e1 is obtained. calculate.

In step S1707, the load torque estimation unit 212 calculates a difference value between the actually measured rotational speed value ω _det1 obtained in step S1702 and the estimated rotational speed value ω _e1 calculated in step S1706.

Furthermore, the load torque estimating unit 212 calculates the estimated value τ _e1 of the load torque by multiplying the torque estimation model Tq (s) ₁ generated and corrected in step S1705 by the difference value.

When the calculation of the estimated value τ _e1 of the load torque is completed in step S1707, the process proceeds to step S1708. In step S1708, the estimation unit 210 determines whether or not to end the load torque estimation process. In the estimation unit 210, when the operation instruction input unit 203 receives the operation stop instruction, it is determined that the load torque estimation process is finished. When the operation instruction input unit 203 does not receive the operation stop instruction, the load torque is estimated. It is determined that the estimation process is maintained.

  If it is determined in step S1708 that the estimation unit 210 maintains the load torque estimation process, the process waits until the next control period, and executes the processes from step S1702 again in the next control period.

That is, after obtaining the control value (voltage value V _ctl2 ) at the timing T2 and the actual measured value ω _det2 of the rotational speed (step S1702), the estimated value τ _e1 of the previous load torque is obtained. Further, a mechanical time constant Tm_τ _e1 and an electric time constant Te_τ _e1 are derived based on the previous estimated value τ _e1 of the load torque (step S1703). Further, after updating the motor nominal model P (s) ₂ and the torque estimation model Tq (s) ₂ with the derived mechanical time constant Tm_τ _e1 and electrical time constant Te_τ _e1 , the fluctuation rate R _t of the coil resistance value is used. (Step S1705). Further, an estimated value ω _e2 of the rotational speed is calculated (step S1706), and an estimated value τ _e2 of the load torque is calculated (step S1707).

  Thereafter, similar processing is repeated in the next control cycle. As a result, at each control cycle, the motor nominal model and the torque estimation model are updated with the mechanical time constant and the electrical time constant corresponding to the previous estimated value of the load torque, and corrected with the fluctuation rate of the coil resistance value. The estimated value of the load torque this time is calculated. As a result, it is possible to accurately calculate the estimated value of the load torque regardless of the magnitude and temperature of the load torque of the electric motor 130.

<3. Coil resistance value calculation process and fault diagnosis process>
The coil resistance value calculation process performed by the control device 100 according to the present embodiment is the same as the coil resistance value calculation process described with reference to FIG. 10 in the first embodiment, and thus the description thereof is omitted here.

  On the other hand, the failure diagnosis process performed by the control device 100 according to the present embodiment is the same as the failure diagnosis process described with reference to FIG. 12 in the first embodiment except for steps S1204 and S1205. For this reason, step S1204 and step S1205 will be described here.

In the case of the control device 100 according to the present embodiment, in step S1204, the time constant deriving unit 221 derives a mechanical time constant Te_τ _e0 and an electric time constant Te_τ _e0 corresponding to the reference load torque. The reference load torque refers to the load torque applied to the electric motor 130 in a state where a predetermined condition (load torque τ = 0) is satisfied.

In step S1205, the rotation speed estimation unit 211 generates a motor nominal model P (s) ₁ based on the mechanical time constant Te_τ _e0 and the electrical time constant Te_τ _e0 derived in step S1204. At this time, the rotational speed estimation unit 211 corrects the motor nominal model P (s) _{1 based} on the correction content using the coil resistance value variation rate R _t . Specifically, the mechanical time constant Tm_τ _e0 is corrected by multiplying the derived mechanical time constant Tm_τ _e0 by the variation rate R _t of the coil resistance value based on Expression 4. Further, the electrical time constant Te_τ _e0 is corrected by dividing the derived electrical time constant Te_τ _e0 by the variation rate R _t of the coil resistance value based on Equation 5.

<4. Summary>
As is clear from the above description, in the control device according to the present embodiment,
-The motor nominal model of the electric motor to be controlled and the load torque estimation model for estimating the load torque related to the electric motor were identified. Also, a configuration for estimating the load torque of the electric motor by using the identified motor nominal model and torque estimation model using the control value (voltage value) for controlling the electric motor and the actual measured value of the rotational speed of the electric motor. It was.
-In identifying the motor nominal model and the torque estimation model, we focused on the fact that the mechanical time constant and the electric time constant fluctuate according to the load torque of the electric motor. Further, the inventors have focused on the point that the coil resistance value included in the mechanical time constant and the electrical time constant varies depending on the temperature.
The mechanical time constant and the electric time constant at each load torque are obtained experimentally in advance and approximated by an approximate expression of the Nth order or stored in a table.
Based on the estimated value of the load torque calculated in the (n-1) th control cycle (n is an integer equal to or greater than 2), the mechanical time constant and the electrical time constant in the nth control cycle are derived, and the motor nominal model and The torque estimation model is generated. Further, the motor nominal model and the torque estimation model generated by the variation rate of the coil resistance value according to the temperature are modified.
Using the control value (voltage value), the actual measured value of the rotational speed of the electric motor, the motor nominal model and the torque estimation model after generation and correction, acquired in the nth control cycle, in the nth control cycle The estimated value of the load torque is calculated.

  As a result, it is possible to avoid the conventional problem that the error of the estimated value of the load torque increases due to fluctuations in the magnitude and temperature of the load torque of the electric motor. As a result, it is possible to improve the estimation accuracy of the load torque of the electric motor.

[Third Embodiment]
In the first and second embodiments, the application destination of the control apparatus 100 is not particularly mentioned. However, the control apparatus 100 can be applied to an image forming apparatus such as an MFP (Multi-Function Peripheral). .

<1. Schematic configuration of image forming apparatus>
FIG. 18 is a diagram illustrating a schematic configuration when the control apparatus 100 is applied to the image forming apparatus 1800. When the control device 100 is applied to the image forming apparatus 1800, the control target of the control device 100 is, for example, a DC motor for driving a transport device that transports a print medium. Also, an instruction for the control device 100 is transmitted from the main body control device 1810, and the control device 100 controls the conveyance of the print medium based on the instruction from the main body control device 1810.

  Specifically, the control device 100 executes the load torque estimation program 110 based on the control information, information on the processing mode, and temperature data transmitted from the main body control device 1810. Further, the estimated value of the load torque and the failure diagnosis result output by executing the load torque estimation program 110 are transmitted to the main body control device 1810.

  Note that an operation device 1820 that accepts various operations from the user and a printing device 1830 that prints image data on a print medium whose conveyance is controlled by the control device 100 are connected to the main body control device 1810. Furthermore, a temperature sensor 1840 that measures the external temperature of the image forming apparatus 1800 is connected to the main body control apparatus 1810, and the main body control apparatus 1810 transmits temperature data measured by the temperature sensor 1840 to the control apparatus 100. .

<2. Operation of control device in image forming apparatus>
Next, processing of the control device 100 applied to the image forming apparatus 1800 will be described with reference to FIG. FIG. 19 is a diagram showing the relationship between the processing mode of the image forming apparatus 1800 and various processes (coil resistance value calculation process, load torque estimation process, failure diagnosis process) executed in the control apparatus 100.

  When the main power supply of the image forming apparatus 1800 is turned on, the image forming apparatus 1800 is activated, and the processing mode becomes the “activation mode” as shown in FIG. When activated in the activation mode, the main body control device 1810 transmits a “coil resistance value calculation mode” to the control device 100 as information regarding the processing mode. Further, an operation start instruction is transmitted to the control device 100 together with a predetermined target rotation speed.

  Thereby, the control device 100 controls the electric motor 130 to operate at the target rotational speed under a predetermined condition (load torque τ = 0). As a result, in the image forming apparatus 1800, as the initial operation at the time of start-up, the “idling operation” for operating the transport device with the print medium in the non-transport state is performed.

  After the idling operation for a predetermined time is performed, the main body control device 1810 transmits an operation stop instruction to the control device 100. As a result, the electric motor 130 stops and the image forming apparatus 1800 ends the initial operation.

  Here, in accordance with the initial operation at the time of activation by the image forming apparatus 1800, the estimation unit 210 of the control apparatus 100 executes a coil resistance value calculation process. Thereby, the estimation part 210 of the control apparatus 100 can update the variation rate of the coil resistance value managed by the coil resistance value management part 222 at the time of activation.

  At this time, since the printing process by the printing apparatus 1830 is not performed, the internal temperature of the image forming apparatus 1800 does not increase, and the internal temperature is substantially equal to the external temperature of the image forming apparatus 1800.

  Here, when the user performs various setting operations on the operation device 1820 and the start button for instructing the start of printing is pressed, the main body control device 1810 shifts to the print mode. When transitioning to the print mode, the image forming apparatus 1800 transmits a “load torque estimation mode” to the control apparatus 100 as information regarding the processing mode. In addition, an operation start instruction is transmitted to the control device 100 together with a predetermined target rotation speed.

  Accordingly, the control unit 200 of the control device 100 starts control of the electric motor 130, and the transport device transports the print medium. The printing apparatus 1830 performs a printing process on the conveyed print medium. When the printing process by the printing apparatus 1830 is performed on a plurality of printing media, the control of the electric motor 130 by the control unit 200 of the control apparatus 100 is continued during the printing process. Further, the load torque estimation process by the estimation unit 210 of the control device 100 is continued, and the calculated estimated value of the load torque is transmitted to the main body control device 1810.

  When the image forming apparatus 1800 performs the printing process on a predetermined number of print media, the image forming apparatus 1800 temporarily shifts to the correction mode, and the printing apparatus 1830 executes various correction processes. The main body control device 1810 transmits a “coil resistance value calculation mode” to the control device 100 as information regarding the processing mode. Furthermore, an operation start instruction is transmitted to the control device 100 together with a predetermined target rotation speed.

  As a result, the control device 100 controls the electric motor 130 to operate at the target rotational speed under a predetermined condition (load torque τ = 0). As a result, in the image forming apparatus 1800, as the initial operation in the correction mode, the “idling operation” is performed in which the transport device is operated with the print medium in the non-transport state.

  After the idling operation for a predetermined time is performed, the main body control device 1810 transmits an operation stop instruction to the control device 100. As a result, the electric motor 130 stops, and the image forming apparatus 1800 ends the initial operation.

  Here, in accordance with the initial operation in the correction mode by the image forming apparatus 1800, the estimation unit 210 of the control apparatus 100 executes a coil resistance value calculation process. Thereby, the estimation part 210 of the control apparatus 100 can update the variation rate of the coil resistance value managed by the coil resistance value management part 222 during the correction mode.

  At this point, since the printing process is being performed by the printing apparatus 1830, the internal temperature of the image forming apparatus 1800 has increased. That is, when the fluctuation rate of the coil resistance value is updated in the correction mode, in the subsequent printing modes, the motor nominal model and the torque estimation model corrected by the fluctuation rate of the coil resistance value according to the increased internal temperature are used. Load torque estimation processing can be performed.

  When the correction mode ends, the image forming apparatus 1800 transitions to the print mode. When transitioning to the print mode, the main body control device 1810 transmits a “load torque estimation mode” to the control device 100 as information regarding the processing mode. In addition, an operation start instruction is transmitted to the control device 100 together with a predetermined target rotation speed.

  Thereby, the control unit 200 of the control device 100 starts the control of the electric motor 130 again, and transports the print medium by the transport device. The printing apparatus 1830 performs a printing process on the conveyed print medium. During the printing process by the printing apparatus 1830, the load torque estimation process by the estimation unit 210 of the control apparatus 100 is continued, and the calculated estimated value of the load torque is transmitted to the main body control apparatus 1810.

  Thereafter, the image forming apparatus 1800 shifts to the correction mode every time printing processing is performed on a predetermined number of print media, performs the initial operation, and then repeats the operation to shift to the print mode. The control device 100 executes a coil resistance value calculation process every time the mode is changed to the correction mode, and executes a load torque estimation process while the mode is changed to the print mode.

  In the example of FIG. 19, the printing process for the number of print media set by the user is completed simultaneously with the printing process for the predetermined number of print media. Therefore, the image forming apparatus 1800 is in a non-printing state after transitioning from the printing mode to the correction mode.

  When the non-printing state continues for a predetermined time, the image forming apparatus 1800 shifts to the energy saving mode. In the energy saving mode, the drive power supply is cut off. Note that during the printing process by the printing apparatus 1830, the internal temperature of the image forming apparatus 1800 was higher than the external temperature. However, when a predetermined time elapses after the printing mode is completed, the temperature drops to substantially the same temperature as the external temperature.

  When it is determined that the internal temperature of the image forming apparatus 1800 has dropped to substantially the same temperature as the external temperature, the main body control device 1810 transmits a “failure diagnosis mode” as information regarding the processing mode to the control device 100. In addition, an operation start instruction is transmitted to the control device 100 together with a predetermined target rotation speed. Thereby, the estimation unit 210 of the control device 100 executes a failure diagnosis process and determines whether or not there is a failure in the drive system including the electric motor 130.

  Note that in the main body control device 1810, when a predetermined time (for example, 5 to 10 minutes) elapses after the printing process by the printing device 1830 is completed, the internal temperature of the image forming apparatus 1800 reaches approximately the same temperature as the external temperature. Judge that it has fallen.

  For example, the main control device 1810 may transmit an operation stop instruction and the stop state of the electric motor 130 may be determined for a predetermined time. Or you may determine with predetermined time having passed since it changed to energy-saving mode. Alternatively, the determination may be made when a predetermined time has elapsed since the driving power supply was shut off. Alternatively, the determination may be made when a predetermined time elapses after the main power supply of the image forming apparatus 1800 is shut off. In any case, when it becomes possible to determine that the internal temperature of the image forming apparatus 1800 has dropped to substantially the same temperature as the external temperature, the main body control device 1810 gives the control device 100 “failure” as information regarding the processing mode. Send "diagnostic mode". Thereby, the fault diagnosis process is executed in the estimation unit 210 of the control device 100.

  After the transition to the energy saving mode, when a user operation is performed on the operation device 1820, the image forming apparatus 1800 enters the energy saving mode release state and the drive power is turned on. Further, when the energy saving mode is released, the main body control device 1810 transmits a “coil resistance value calculation mode” as information on the processing mode to the control device 100. Furthermore, an operation start instruction is transmitted to the control device 100 together with a predetermined target rotation speed.

  Thereby, the control unit 200 of the control device 100 controls the electric motor 130 to operate at the target rotational speed under a predetermined condition (load torque τ = 0). As a result, in the image forming apparatus 1800, as the initial operation after canceling the energy saving mode, the “idling operation” for operating the transport device with the print medium in the non-transport state is performed.

  After the idling operation for a predetermined time is performed, the main body control device 1810 transmits an operation stop instruction to the control device 100. As a result, the electric motor 130 stops, and the image forming apparatus 1800 ends the initial operation.

  Here, in accordance with the initial operation after the energy saving mode is canceled by the image forming apparatus 1800, the estimation unit 210 of the control apparatus 100 performs a coil resistance value calculation process. Thereby, in the estimation part 210 of the control apparatus 100, the fluctuation rate of the coil resistance value managed by the coil resistance value management part 222 can be updated after energy-saving mode cancellation | release.

<3. Relationship between internal temperature of image forming apparatus and estimated value of load torque>
Next, the relationship between the internal temperature of the image forming apparatus 1800 and the estimated value of the load torque will be described. FIG. 20 is a diagram showing the relationship between the internal temperature of the image forming apparatus 1800 and the estimated value of the load torque.

  In FIG. 20A, the horizontal axis represents time, and the vertical axis represents the load torque τ actually applied to the electric motor 130. In the example of FIG. 20 (a), after applying a load torque of the same magnitude for a certain period of time, the load torque is increased over time, and after reaching a predetermined load torque, the load torque is increased over time. Decrease. Then, after returning to the initial load torque, the load torque of the same magnitude is applied again for a certain time.

  In FIG. 20B, the horizontal axis represents time, and the vertical axis represents the internal temperature of the image forming apparatus 1800. In the example of FIG. 20B, the internal temperature of the image forming apparatus 1800 increases as time passes, and the temperature is maintained after reaching a predetermined temperature.

In FIG. 20C, the horizontal axis represents time, and the vertical axis represents the estimated value τ _e of the load torque. Since the coil resistance value fluctuates due to an increase in the internal temperature of the image forming apparatus 1800, in the example of FIG. 20C, the actual load torque (FIG. 20) until the coil resistance value calculation process is executed. The estimated value of the load torque (solid line 2000 in FIG. 20C) is calculated higher than the dotted line 2001 in FIG.

  On the other hand, when the coil resistance value calculation process is executed and the fluctuation rate of the coil resistance value is updated, the motor nominal model and the torque estimation model are corrected. Therefore, the estimated value of the load torque is approximately equal to the actual load torque. (Solid line 2003 in FIG. 20C). That is, if the coil resistance value calculation process is not executed, an error associated with the temperature increase is included (dotted line 2002 in FIG. 20C), and the coil resistance value calculation process is executed, thereby increasing the temperature. The accompanying error will be eliminated.

  As described above, by executing the coil resistance value calculation process, the fluctuation rate of the coil resistance value updated in response to the change in the state (temperature) of the control target is reflected in the motor nominal model and the torque estimation model. Therefore, the estimation accuracy of the load torque of the electric motor is improved.

[Fourth Embodiment]
In the first and second embodiments, the rotation speed and the load torque are cited as changes in the state of the electric motor that is the control target. Then, by conducting an experiment separately for each, the relationship between the rotational speed, the mechanical time constant and the electrical time constant, and the relationship between the load torque, the mechanical time constant and the electrical time constant are obtained, and an approximate expression or table is obtained for each. It was set as the structure which creates.

  However, the present invention is not limited to this, and an approximate expression or a table may be created for fluctuations in the mechanical time constant and the electric time constant in consideration of the effects of both the rotational speed and the load torque. .

  Specifically, experiments were performed on various combinations of rotational speed and load torque, electric time constants and mechanical time constants were obtained, and in each control cycle, the actual value of rotational speed and the previous estimated value of load torque were May be used to derive the electrical time constant and the mechanical time constant.

  Thereby, it is possible to calculate the estimated value of the load torque with higher accuracy.

[Fifth Embodiment]
In the first and second embodiments, both the mechanical time constant and the electrical time constant are derived for each control cycle. However, the present invention is not limited to this. As shown in FIG. 8 and FIG. 16, when the fluctuation of the mechanical time constant due to the change of the rotational speed or the load torque is compared with the fluctuation of the electric time constant accompanying the change of the rotational speed or the load torque, the fluctuation of the mechanical time constant Is bigger.

  Therefore, only a mechanical time constant may be derived for each control period, and a predetermined value may be substituted in advance for the electrical time constant.

[Sixth Embodiment]
In the first and second embodiments, the case has been described in which the control device 100 performs feedback control so that the measured value of the rotational speed is fed back and the electric motor 130 rotates at the target rotational speed. Alternatively, the case has been described in which the control device 100 performs feedback control so that the actual value of the position information is fed back and the electric motor 130 rotates to the target position.

  However, in the present invention, the control performed by the control device 100 is not limited to this. For example, the speed feedforward control may be performed from the target rotation speed, or the position feedforward control may be performed from the target position.

[Seventh Embodiment]
In the third embodiment, the image forming apparatus 1800 is exemplified as an application destination of the control apparatus 100. However, the present invention is not limited to this, and can be applied to an automobile, a robot, an amusement device, and the like.

  It should be noted that the present invention is not limited to the configuration shown here, such as a combination with other elements in the configuration described in the above embodiment. These points can be changed without departing from the spirit of the present invention, and can be appropriately determined according to the application form.

100: Control device 101: CPU
102: ROM
103: RAM
104: Storage device 105: Interface unit 106: Bus 110: Load torque estimation program 120: Motor drive device 130: Electric motor 140: Position / rotation speed detection unit 150: Input unit 160: Display unit 200: Control unit 201: Target rotation Speed input unit 202: Target position input unit 203: Operation instruction input unit 204: Processing mode input unit 205: Temperature data input unit 206: Estimated torque value output unit 207: Diagnosis result output unit 208: Actual value input unit 209: Control value Output unit 210: Estimating unit 211: Rotational speed estimating unit 212: Load torque estimating unit 213: Coil resistance value calculating unit 214: Failure diagnosis unit 221: Time constant deriving unit 222: Coil resistance value managing unit 1800: Image forming apparatus 1810: Main body control device 1820: operation device 1830: printing device 1840: temperature sensor Sensor

JP 2008-137450 A

Claims (16)

A control device for controlling an electric motor,
Derivation means for deriving a mechanical time constant and an electric time constant of the electric motor corresponding to an actual measurement value of the rotation speed of the electric motor;
An estimated value of the rotational speed of the electric motor calculated by inputting a control value for controlling the electric motor to the motor nominal model updated with the derived mechanical time constant and electric time constant, and the electric motor Calculation means for calculating an estimated value of the load torque of the electric motor by inputting the measured value of the rotational speed of the motor to a torque estimation model updated by the derived mechanical time constant and electrical time constant. Have
The motor nominal model and the torque estimation model that are updated when calculating the estimated value are determined in advance according to a difference value between the estimated value and the actually measured value when the electric motor is controlled under a predetermined condition. A control device that is corrected based on the correction content. A control device for controlling an electric motor,
By inputting an estimated value of the rotational speed of the electric motor calculated using a motor nominal model based on a control value for controlling the electric motor and an actual measured value of the rotational speed of the electric motor to the torque estimation model. Calculating means for calculating an estimated value of the load torque of the electric motor;
Deriving means for deriving a mechanical time constant and an electric time constant of the electric motor corresponding to the calculated estimated value of the load torque,
The calculating means includes
The motor nominal model and the torque estimation model updated with the mechanical time constant and the electrical time constant corresponding to the estimated value of the load torque calculated in the (n-1) th (n is an integer of 2 or more) control cycle. And calculating an estimated value of the load torque in the nth control cycle,
The motor nominal model and the torque estimation model that are updated when calculating the estimated value are the difference values between the estimated value of the rotational speed and the measured value of the rotational speed when the electric motor is controlled under a predetermined condition. A control device that is corrected based on a predetermined correction content accordingly. The mechanical time constant and electrical time constant are:
Using the variation rate of the coil resistance value of the electric motor determined according to the difference value between the estimated value of the rotational speed and the measured value of the rotational speed when the electric motor is controlled under the predetermined condition The control device according to claim 1, wherein the control device is modified.   Fluctuations in the coil resistance value of the electric motor so that a difference value between the estimated value of the rotational speed and the measured value of the rotational speed when the electric motor is controlled under the predetermined condition falls within a predetermined range. 4. The control device according to claim 3, wherein the rate is determined. Using the motor nominal model corrected based on the correction content determined in advance according to the ambient temperature of the electric motor, the estimated value and the measured value when the electric motor is controlled under a predetermined condition Determining means for determining whether or not the difference value is within a predetermined range;
3. The control according to claim 1, further comprising: a diagnosis unit that diagnoses that the drive by the electric motor is not normal when it is determined by the determination unit that the drive is not within a predetermined range. apparatus. An image forming apparatus that controls an electric motor for conveying a print medium and prints an image on the print medium,
Derivation means for deriving a mechanical time constant and an electric time constant of the electric motor corresponding to an actual measurement value of the rotation speed of the electric motor;
An estimated value of the rotational speed of the electric motor calculated by inputting a control value for controlling the electric motor to the motor nominal model updated with the derived mechanical time constant and electric time constant, and the electric motor Calculation means for calculating an estimated value of the load torque of the electric motor by inputting the measured value of the rotational speed of the motor to a torque estimation model updated by the derived mechanical time constant and electrical time constant. Have
The motor nominal model and the torque estimation model that are updated when calculating the estimated value are determined in advance according to a difference value between the estimated value and the actually measured value when the electric motor is controlled under a predetermined condition. An image forming apparatus that is corrected based on correction contents. An image forming apparatus that controls an electric motor for conveying a print medium and prints an image on the print medium,
By inputting an estimated value of the rotational speed of the electric motor calculated using a motor nominal model based on a control value for controlling the electric motor and an actual measured value of the rotational speed of the electric motor to the torque estimation model. Calculating means for calculating an estimated value of the load torque of the electric motor;
Deriving means for deriving a mechanical time constant and an electric time constant of the electric motor corresponding to the calculated estimated value of the load torque,
The calculating means includes
The motor nominal model and the torque estimation model updated with the mechanical time constant and the electrical time constant corresponding to the estimated value of the load torque calculated in the (n-1) th (n is an integer of 2 or more) control cycle. And calculating an estimated value of the load torque in the nth control cycle,
The motor nominal model and the torque estimation model that are updated when the estimated value is calculated include an estimated value of the rotational speed and an actual measured value of the rotational speed when the electric motor is controlled in a non-transport state of the print medium. The image forming apparatus is corrected based on a correction content that is determined in advance according to the difference value. The estimated value when the electric motor is controlled in the non-conveyance state of the print medium using the motor nominal model corrected based on the correction content predetermined according to the internal temperature of the image forming apparatus. Determination means for determining whether or not a difference value from the actual measurement value is within a predetermined range;
8. The image according to claim 6, further comprising: a diagnosis unit that diagnoses that the drive by the electric motor is not normal when it is determined by the determination unit that the drive is not within a predetermined range. Forming equipment. The determination means includes
It is determined whether or not a difference value between the estimated value and the measured value when the electric motor is controlled based on an instruction from a user in a non-conveying state of the print medium is within a predetermined range. The image forming apparatus according to claim 8. The determination means includes
In a non-conveying state of the print medium, a difference value between the estimated value and the actually measured value when the electric motor is controlled by determining that the internal temperature of the image forming apparatus is substantially equal to the external temperature is a predetermined value. The image forming apparatus according to claim 8, wherein the image forming apparatus determines whether the image is within the range.   The image according to claim 10, wherein the internal temperature of the image forming apparatus is determined to be substantially equal to the external temperature when a predetermined time elapses after the power supply for driving the image forming apparatus is turned off. Forming equipment.   The image forming apparatus according to claim 10, wherein the internal temperature of the image forming apparatus is determined to be substantially equal to the external temperature when the electric motor is stopped for a predetermined time. A control method in a control device for controlling an electric motor,
A derivation step for deriving a mechanical time constant and an electric time constant of the electric motor corresponding to an actual measurement value of the rotation speed of the electric motor;
An estimated value of the rotational speed of the electric motor calculated by inputting a control value for controlling the electric motor to the motor nominal model updated with the derived mechanical time constant and electric time constant, and the electric motor A calculation step of calculating an estimated value of the load torque of the electric motor by inputting the measured value of the rotation speed to the torque estimation model updated by the derived mechanical time constant and electric time constant. Have
The motor nominal model and the torque estimation model that are updated when calculating the estimated value are determined in advance according to a difference value between the estimated value and the actually measured value when the electric motor is controlled under a predetermined condition. A control method characterized by correction based on the correction content. A control method in a control device for controlling an electric motor,
By inputting an estimated value of the rotational speed of the electric motor calculated using a motor nominal model based on a control value for controlling the electric motor and an actual measured value of the rotational speed of the electric motor to the torque estimation model. Calculating a load torque estimated value of the electric motor;
A derivation step for deriving a mechanical time constant and an electric time constant of the electric motor corresponding to the calculated estimated value of the load torque,
The calculation step includes
The motor nominal model and the torque estimation model updated with the mechanical time constant and the electrical time constant corresponding to the estimated value of the load torque calculated in the (n-1) th (n is an integer of 2 or more) control cycle. And calculating an estimated value of the load torque in the nth control cycle,
The motor nominal model and the torque estimation model that are updated when calculating the estimated value are the difference values between the estimated value of the rotational speed and the measured value of the rotational speed when the electric motor is controlled under a predetermined condition. The control method is characterized in that the correction is performed based on a predetermined correction content. In the computer of the control device that controls the electric motor,
A derivation step for deriving a mechanical time constant and an electric time constant of the electric motor corresponding to an actual measurement value of the rotation speed of the electric motor;
An estimated value of the rotational speed of the electric motor calculated by inputting a control value for controlling the electric motor to the motor nominal model updated with the derived mechanical time constant and electric time constant, and the electric motor A calculation step of calculating an estimated value of the load torque of the electric motor by inputting the measured value of the rotation speed to the torque estimation model updated by the derived mechanical time constant and electric time constant. A program for executing the program,
The motor nominal model and the torque estimation model that are updated when calculating the estimated value are determined in advance according to a difference value between the estimated value and the actually measured value when the electric motor is controlled under a predetermined condition. A program that is modified based on the modification content. In the computer of the control device that controls the electric motor,
By inputting an estimated value of the rotational speed of the electric motor calculated using a motor nominal model based on a control value for controlling the electric motor and an actual measured value of the rotational speed of the electric motor to the torque estimation model. Calculating a load torque estimated value of the electric motor;
A derivation step for deriving a mechanical time constant and an electric time constant of the electric motor corresponding to the calculated estimated value of the load torque,
The calculation step includes
The motor nominal model and the torque estimation model updated with the mechanical time constant and the electrical time constant corresponding to the estimated value of the load torque calculated in the (n-1) th (n is an integer of 2 or more) control cycle. And calculating an estimated value of the load torque in the nth control cycle,
The motor nominal model and the torque estimation model that are updated when calculating the estimated value are the difference values between the estimated value of the rotational speed and the measured value of the rotational speed when the electric motor is controlled under a predetermined condition. A program that is modified based on a predetermined content of modification.

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