JP2008240894A - Flow control method and flow control device for servo pump of continuously variable transmission - Google Patents

Abstract

To provide a flow rate control method and a flow rate control device for a servo pump of a continuously variable transmission that can simplify system control and are suitable for energy saving.
A transmission ratio of a continuously variable transmission (1) is controlled by hydraulic oil supplied to hydraulic actuators (11, 14). The flow rate of hydraulic oil is controlled by servo pumps 15 and 16. A servo pump system is constructed using a state variable model that receives input voltages V _{set, P} and V _{set, S} to the servo amplifiers 19 and 21 of the servo pumps 15 and 16. State feedback control is performed so that the primary flow rate Q _P and the secondary flow rate Q _S supplied to the hydraulic actuators of the primary pulley and the secondary pulley become the target flow rates Q _{P, R} , Q _{S, R.}
[Selection] Figure 1

Description

  The present invention relates to a flow rate control method and a flow rate control device for controlling the flow rate of a servo pump for changing a gear ratio, for example, in a continuously variable transmission of a vehicle.

Conventionally, there is a device proposed in Patent Document 1 as a transmission device of a belt type CVT.
In this type of apparatus, a pair of hydraulic actuators for changing the effective diameters of the primary pulley and the secondary pulley are provided. A control valve is provided for controlling the hydraulic pressure of the hydraulic actuator that generates the clamping force of the primary pulley, and a relief valve is provided for controlling the hydraulic pressure of the hydraulic actuator that generates the clamping force of the secondary pulley.
Patent No. 2606350

The conventional general control uses a valve for setting the pressure supplied to the hydraulic actuator related to the transmission ratio of the CVT to a required value, and a hydraulic pump for supplying hydraulic oil to the hydraulic actuator. Was connected to the vehicle engine.
The hydraulic pump is designed to ensure sufficient pressure under all conditions. For this reason, energy loss is large, which is not preferable for energy saving.

  The present invention has been made in view of the above problems, and an object thereof is to provide a flow control method and a flow control device for a servo pump of a continuously variable transmission that can simplify system control and are suitable for energy saving. And

The inventor of the present application has focused on the fact that a servo pump system can be applied to control a continuously variable transmission. That is, it has been found that the pressure required for the hydraulic actuator can be set by the flow rate supplied to the hydraulic actuator by the servo pump.
The present invention has been made on the basis of the above knowledge, wherein the transmission ratio of the continuously variable transmission is controlled by the hydraulic oil supplied to the hydraulic actuator, and the flow rate of the hydraulic oil supplied to the hydraulic actuator is the electric motor. Using a state variable of a state variable model of a servo pump system, which is controlled by a servo pump driven by a servo pump and inputs an input voltage to the servo amplifier of the electric motor or a state quantity having a linear relationship with the input voltage. The present invention provides a flow rate control method for a servo pump of a continuously variable transmission, wherein state feedback control is performed so that the flow rate of hydraulic oil supplied to a hydraulic actuator becomes a target flow rate.

The servo pump is driven by the electric motor, and the flow rate of the servo pump is proportional to the rotational speed w of the electric motor. Specifically, the flow rate Q of the servo pump is expressed by the following equation (1), where D _V is the stroke volume of the servo pump and η _V is the capacity efficiency of the servo pump.
Q = D _V · w · η _V (1)
The rotational speed w of the electric motor is _set by, for example, an input voltage _Vset input to a servo amplifier of the electric motor. The rotational speed w of the electric motor is expressed by a quadratic function as shown in the following formula (2) using a constant K obtained by experiment or analysis using a detailed model of the motor / inverter.

w (s) = K · [1 / (a · s ² + b · s + 1)] · V _set (2)
From Equation (1) and Equation (2),
Q = G · [1 / (a · s ² + b · s + 1)] · V _set (3)
However, G = D _V · η _V · K (4)
And a state space type | formula is represented by following formula (5-1) and (5-2).

ここで、入力ベクトルｕは、ｕ＝Ｖ_set であり、出力ベクトルｙは、ｙ＝Ｑであり、
状態変数ベクトルｘは、ｘ＝〔Ｑ ｄＱ／ｄｔ〕^T である。
これにより、サーボポンプの状態変数モデルを作成し、状態フィードバックを用いることにより、流量制御の安定性を向上することができる。すなわち、状態フィードバックでは、プラントの内部状態を利用することで見かけ上の動的要素を引き出すことができ、これにより、動的補償を実現することができる。その結果、流量制御の安定性を確保することができる。

Here, the input vector u is u = V _set , the output vector y is y = Q,
The state variable vector x is x = [Q dQ / dt] ^T.
Thereby, the state variable model of a servo pump is created, and the stability of flow control can be improved by using state feedback. That is, in the state feedback, an apparent dynamic element can be extracted by using the internal state of the plant, and thus dynamic compensation can be realized. As a result, the stability of the flow control can be ensured.

Moreover, the response of flow control can be improved by setting the position of the pole of the state feedback. That is, the poles of the closed loop system can be placed at any desired location on the complex plane by using a constant linear combination of state variables.
Furthermore, the conventionally used valves and pressure sensors can be eliminated, and the hydraulic circuit can be simplified. In addition, the servo pump can be operated as necessary to supply the required flow rate without excess or deficiency, so that energy saving can be achieved.

As the state quantity having a linear relationship with the above input voltage, for example, there is a drive current of an electric motor.
Further, when the observer is configured using the state variable model and the state variable is estimated by the observer (claim 2), the estimation accuracy of the state variable can be effectively improved, and as a result, Good design of servo system by state feedback becomes possible. Further, the state feedback system in which the observers are merged has the advantage that the state feedback control design and the observer control design can be performed independently (that is, the observer design is separable).

  The present invention also includes an input rotation element, an output rotation element, and a power transmission element that transmits power between the input rotation element and the output rotation element, and each of the input rotation element and the output rotation element is connected to the power transmission element. A continuously variable transmission that can change the gear ratio steplessly by changing the contact diameter with a hydraulic actuator, a servo pump driven by an electric motor to supply hydraulic oil to the hydraulic actuator, and this servo pump A controller for controlling the state variable of the state variable model of the servo pump system that receives an input voltage to the servo amplifier of the electric motor or a state quantity having a linear relationship with the input voltage. To control the state so that the flow rate of the hydraulic oil supplied to the hydraulic actuator becomes the target flow rate. It has a function to provide a flow control device of a servo pump for a continuously variable transmission, wherein (claim 3).

In this case, the stability and responsiveness of the flow rate control can be improved. Moreover, the conventionally used valve can be eliminated and the hydraulic circuit can be simplified. In addition, the servo pump can be operated as necessary to supply the required flow rate without excess or deficiency, so that energy saving can be achieved. For example, if the leakage of the hydraulic circuit can be ignored under stable conditions, the servo pump can be stopped.
7 In the control device, the controller includes an observer configured using a state variable model, and when the observer estimates the state variable (claim 4), the state variable estimation accuracy is effectively improved. As a result, a good design of the servo system by state feedback becomes possible. Further, in the state feedback system in which the observer is merged, the observer design can be separated from the state feedback design.

The input rotation element is a variable diameter primary pulley (6), the output rotation element is a variable diameter secondary pulley (7), and the power transmission element is wound around the primary pulley and the secondary pulley. A belt (8) or a chain, wherein the hydraulic actuator is a contact between the first hydraulic actuator (11) for changing the contact diameter of the primary pulley with the power transmission element and the power transmission element of the secondary pulley. A second hydraulic actuator (14) for changing the diameter, and the servo pump includes a first servo pump (15) and a second servo pump (16). The primary flow rate (Q _P ), which is the flow rate of the hydraulic oil supplied to the hydraulic actuator, is the flow rate discharged by the first servo pump, and the second hydraulic actuator The secondary flow rate (Q _S ), which is the flow rate of hydraulic oil supplied to the engine, is obtained by subtracting the flow rate discharged from the first servo pump from the flow rate discharged from the second servo pump (Q _S = Q _SP −Q _P (Claim 5).

In this case, the second servo pump acts on both the first and second hydraulic actuators to control the clamping force on the belt and the like in the primary pulley and the secondary pulley. The first servo pump controls the transmission ratio of the continuously variable transmission by adjusting the differential pressure between the first and second hydraulic actuators.
When viewed as a pure hydraulic system, the servo pump system is approximated as a multiple input multiple output (MIMO) linear model. That is,

ただし、式（６−１）において、各係数ａ_P ，ｂ_P ，Ｇ_P は、第１のサーボポンプにおいて、式（３）に対応する係数であり、各係数ａ_S ，ｂ_S ，Ｇ_S は、第２のサーボポンプにおいて、式（３）に対応する係数である。

However, in the equation (6-1), the coefficients a _P , b _P , and _GP are coefficients corresponding to the equation (3) in the first servo pump, and the coefficients a _S , b _S , and G _S Is a coefficient corresponding to Equation (3) in the second servo pump.

In addition, the state variable vector x, the input vector u, and the output vector y are represented by the following equations (7-1), (7-2), and (7-3), respectively.
x = [Q _P dQ _P / dt Q _SP dQ _SP / dt] ^T (7-1)
u = [V _{set, S} V _{set, P} ] ^T (7-2)
y = [Q _P Q _S ] ^T (7-3)
Then, it is possible to construct an observer by using in principle the plant state variable model obtained by the equations (6-1) and (6-2). In addition, the position of the system pole may be determined by a simulation test using an actual machine so that sufficient stability of the system and sufficient dynamic characteristics (transient response related to target value tracking, etc.) can be obtained. preferable. However, in order to use it for control of a continuously variable transmission, it is necessary that the response of the hydraulic actuator be much faster than the response of the continuously variable transmission.

  A branch portion is provided in the middle of the oil passage connecting the second servo pump and the second hydraulic actuator, and the first servo pump connects the branch portion and the first hydraulic actuator. May be disposed in an oil passage (claim 6). As a result, the primary flow rate can be set to the flow rate discharged from the first servo pump, and the secondary flow rate can be substantially changed from the flow rate discharged from the second servo pump to the flow rate discharged from the first servo pump. .

Preferred embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a schematic diagram of a vehicle equipped with a continuously variable transmission to which a flow rate control method and a flow rate control device for a servo pump according to an embodiment of the present invention are applied.
The continuously variable transmission 1 includes an input shaft 3 connected to the output shaft of the engine 2 so as to be able to transmit torque, an output shaft 5 connected to the drive wheels 50 via the gear train 4, and an input shaft 3. Primary pulley 6 with a variable diameter as an input rotation element provided so as to be able to rotate along with the output shaft, a secondary pulley 7 with a variable diameter as an output rotation element provided so as to be able to rotate along with the output shaft 5, a primary pulley 6 and a secondary pulley And a belt 8 as a power transmission element wound around the pulley 7. Instead of the belt 8, a chain may be used.

The primary pulley 6 includes a fixed sheave 9 and a movable sheave 10 that are provided so as to be able to rotate along with the input shaft 3. The axial movement of the fixed sheave 9 with respect to the input shaft 3 is restricted, and the axial movement of the movable sheave 10 with respect to the input shaft 3 is allowed. Between the power transmission surfaces 9a and 10a of the fixed sheave 9 and the movable sheave 10, the belt 8 is clamped so that power can be transmitted. A first hydraulic actuator 11 is provided on the back surface of the movable sheave 10. Hydraulic P _P of the oil chamber 11a of the first hydraulic actuator 11 urges the movable sheave 10 toward the fixed sheave 9 side.

The secondary pulley 7 includes a fixed sheave 12 and a movable sheave 13 that are provided so as to be able to rotate along with the output shaft 5. The fixed sheave 12 is restricted from moving in the axial direction with respect to the output shaft 5, and the movable sheave 13 is movable in the axial direction with respect to the output shaft 5. Between the power transmission surfaces 12a and 13a of the fixed sheave 12 and the movable sheave 13, the belt 8 is clamped so that power can be transmitted. A second hydraulic actuator 14 is provided on the back surface of the movable sheave 13. Hydraulic P _S of the oil chamber 14a of the second hydraulic actuator 14 urges the movable sheave 13 toward the fixed sheave 12 side.

By changing the contact diameters R1 and R2 of the primary pulley 6 and the secondary pulley 7 with the belt 8 by the first and second actuators 11 and 14, the speed ratio of the continuously variable transmission 1 can be changed steplessly. It is.
The continuously variable transmission 1 includes a first servo pump 15 and a second servo pump 16. Primary flow Q _P is the flow rate of the hydraulic fluid supplied to the first hydraulic actuator 11 corresponds to a flow in which the first servo pump 15 is discharged. In the following, also represented by Q _P for a flow rate of the first servo pump 15.

The secondary flow rate Q _S, which is the flow rate of the hydraulic oil supplied to the second hydraulic actuator 14, is obtained by subtracting the flow rate Q _P discharged from the first servo pump 15 from the flow rate Q _SP discharged from the second servo pump 16. Flow rate. That is,
Q _S = Q _SP −Q _P
Specifically, a branch portion 17a is provided in the middle of an oil passage 17 connecting the second servo pump 16 and the second hydraulic actuator 14, and the branch portion 17a and the first hydraulic actuator 11 are connected to each other. The first servo pump 15 is disposed in the oil passage 18 that performs the operation. The suction side of the second servo pump 16 is connected to the oil tank 51.

The first servo pump 15 is driven by a first electric motor 20 (servo motor) that receives power supply from the first servo amplifier 19, and the second servo pump 16 receives power from the second servo amplifier 21. It is driven by a second electric motor 22 (servo motor) that receives the supply.
The controller 23 for controlling the flow rates of the servo pumps 15 and 16 of the continuously variable transmission 1 includes the first hydraulic actuator 11 from the main controller 24 that controls the drive system including the engine 2 of the vehicle. The target flow rate Q _{P, R} (corresponding to the target value of the primary flow rate Q _P ) of the hydraulic oil to be supplied to the second hydraulic fluid and the target flow rate Q _{S, R} (secondary flow rate Q of the hydraulic oil to be supplied to the second hydraulic actuator 14 Equivalent to the target value of _S ).

The controller 23, these target flow rate Q _{P, R} and the target amount Q _S, based on the _R, the input voltage V _set to the first servo amplifier _19, the input voltage V _set to _P and the second servo amplifier 21 _{, S} are controlled to control the primary flow rate Q _P and the secondary flow rate Q _S.
The second servo pump 16 functions on both the first hydraulic actuator 11 and the second hydraulic actuator 14 to control the clamping force on the belt 8 in the primary pulley 6 and the secondary pulley 7. Further, the first servo pump 15 controls the gear ratio of the continuously variable transmission 1 by adjusting the differential pressure (P _P −P _S ) between the first and second hydraulic actuators 11 and 14. To work.

  A continuously variable transmission 1, first and second servo pumps 15 and 16, a controller 23, and the like, and controls the flow rates of both servo pumps 15 and 16 in order to change the gear ratio of the continuously variable transmission 1. A servo pump system 30 is constructed. The controller 23 is provided with an observer 34 for estimating a state variable, which will be described later, and a state feedback control unit 35 that performs state feedback control using the state variable estimated by the observer 34.

FIG. 2 is a block diagram showing the servo pump system 30. The servo pump system 30 includes a plant 31 to be controlled, a feedforward control unit 32, a main feedback control unit 33, an observer 34, and a state feedback control unit 35 based on modern control theory.
The flow rates Q _P and Q _SP of the servo pumps 15 and 16 are proportional to the rotational speeds of the corresponding electric motors 19 and 21, respectively. The servo amplifiers 19 and 21 perform speed control (rotational speed control) by feeding back signal outputs from rotational speed sensors 25 and 26 built in the corresponding electric motors 19 and 21. The servo amplifiers 19 and 21 control a control current for the electric motors 19 and 21 by feeding back a signal output from a current sensor (not shown) that detects a drive current of the corresponding electric motors 19 and 21. .

Since the flow rates Q _P and Q _SP of the servo pumps 15 and 16 can be detected by using the rotational speed sensors 25 and 26 originally provided in the electric motors 19 and 21, respectively, There is no need to provide a sensor.
The main feedback control unit 33, the deviation between the output y from the target flow rate y _r and the observer 34 (y _r -y), and a main feedback gain multiplication unit 36 for multiplying the main feedback gain L _1.

The observer 34 is configured by using a state variable model equivalent to the plant 31 in principle, and receives an input vector u and an output vector w (corresponding to the rotational speed of the electric motor) from the plant 31, and the state variable vector x and Estimate the output vector y and output these.
The state feedback control unit 35 includes a state feedback gain multiplication unit 37 that multiplies the state variable vector x estimated by the observer 34 by a predetermined state feedback gain (−L ₂ ).

Next, a basic state variable model for configuring the observer 34 will be described.
First, the flow rate Q of the servo pump is proportional to the rotational speed w of the electric motor that drives the servo pump. That is, the flow rate Q of the servo pump is expressed by the following formula (1), where D _V is the stroke volume of the servo pump and η _V is the volumetric efficiency of the servo pump.

Q = D _V · w · η _V (1)
On the other hand, the rotational speed w of the electric motor is _set by the input voltage V _set input to the servo amplifier of the electric motor. The rotational speed w of the electric motor 20 is expressed by a quadratic function as shown in the following equation (2) using a constant K obtained by experiment or analysis using a detailed model of a motor / inverter.

w (s) = K · [1 / (a · s ² + b · s + 1)] · V _set (2)
From Equation (1) and Equation (2),
Q = G · [1 / (a · s ² + b · s + 1)] · V _set (3)
However, G = D _V · η _V · K (4)
And the state space equation is

ここで、入力ベクトルｕは、ｕ＝Ｖ_set であり、出力ベクトルｙは、ｙ＝Ｑであり、
状態変数ベクトルｘは、ｘ＝〔Ｑ ｄＱ／ｄｔ〕^T である。
図１の無段変速機１に適用されたサーボポンプシステム３０は、このシステムを純粋な油圧システムとしてみた場合、多入力多出力（MIMO）の線形モデルとして近似される。すなわち、

Here, the input vector u is u = V _set , the output vector y is y = Q,
The state variable vector x is x = [Q dQ / dt] ^T.
The servo pump system 30 applied to the continuously variable transmission 1 in FIG. 1 is approximated as a multi-input multi-output (MIMO) linear model when this system is viewed as a pure hydraulic system. That is,

ただし、式（８−３）、式（８−４）において、各係数ａ_P ，ｂ_P ，Ｇ_P は、第１のサーボポンプ１５において、式（３）に対応する係数であり、各係数ａ_S ，ｂ_S ，Ｇ_S は、第２のサーボポンプ１６において、式（３）に対応する係数である。

However, in the expressions (8-3) and (8-4), the coefficients a _P , b _P , and _GP are coefficients corresponding to the expression (3) in the first servo pump 15, and each coefficient a _S , b _S , and G _S are coefficients corresponding to Equation (3) in the second servo pump 16.

Further, the state variable vector x, the input vector u, and the output vector y are expressed by the following equations (9-1), (9-2), and (9-3), respectively.
x = [Q _P dQ _P / dt Q _SP dQ _SP / dt] ^T (9-1)
u = [V _{set, S} V _{set, P} ] ^T (9-2)
y = [Q _P Q _S ] ^T (9-3)
When the flow rate Q _SP of the second servo pump 16 that functions as a clamping pump that applies a clamping force to the belt 8 to each variable diameter pulley 6 and 7 is a constant, the first servo pump 15 that functions as a transmission pump input voltage V _{the set,} change in _P to the servo amplifier 19 (corresponding to the change in the rotational speed of the electric motor 20) will affect both the primary flow Q _P and the secondary flow Q _S.

Also, when the primary flow Q _P, which corresponds to the flow rate of the first servo pump 15 is a constant, the input voltage V _set to the servo amplifier 21 of the second servo pump _16, the change in _S is the secondary flow Q _S affect is, it will not affect the primary flow rate Q _P.
The observer 34 estimates the state variable vector x and the output vector y using the input u and the rotational speed w (measured value or estimated value) of the electric motor. In principle, the above-described equation as a state equation is used. It is a state variable model obtained using (8-1) and Formula (8-2). That is, a block diagram of the observer 34 is shown in FIG. 3, for example.

However, the input vector u _obs is u _obs = [u w] ^T , and each coefficient matrix A _obs , B _obs , C _obs is also different in dimension from the state variable model of the plant 31.
Thus, by creating a state variable model of the servo pump system 30 and using state feedback, the stability of the flow rate control can be improved. That is, in the state feedback, an apparent dynamic element can be derived by using the internal state of the plant 31, and thus dynamic compensation can be realized. As a result, the stability of the flow control can be ensured.

The system shown in FIG. 2 is a regulator system using state feedback and an observer. The internal circuit is controlled so as to always maintain the internal state of the plant at zero, and the external circuit can be seen by a servo pump. Control plant output to prevent strict regulation problems.
Moreover, the response of flow control can be improved by setting the position of the pole of the state feedback. That is, the poles of the closed loop system can be placed at any desired location on the complex plane by using a constant linear combination of state variables.

  Furthermore, conventionally used valves and pressure sensors can be eliminated, and the hydraulic circuit can be simplified. Moreover, since each servo pump 15 and 16 should operate | move as needed and should supply the required flow volume without excess and deficiency, energy saving can be aimed at. For example, if leakage of the hydraulic circuit or the like can be ignored under stable conditions, it is possible to stop at least one of the servo pumps 15 and 16.

  Further, since the observer 34 is configured using the state variable model and the state variable is estimated by the observer 34, the estimation accuracy of the state variable can be effectively improved, and as a result, the servo system based on the state feedback is obtained. Can be designed well. Further, the state feedback system in which the observer 34 is merged also has an advantage that the design of the observer 34 can be performed independently from the design of the state feedback control unit 35.

  As for the position of the pole of the servo pump system 30, sufficient stability and sufficient system stability can be obtained by a simulation test using a test device (which may be an actual machine or a simulator that models the actual machine). It is preferable to determine the position where dynamic characteristics (transient response related to target value tracking, etc.) can be obtained. The response needs to be so fast that the dynamic characteristics of the actuator (corresponding to the servo pumps 15 and 16 in the servo pump system 30) can be ignored.

In the above embodiment, the rotational speed sensors 25 and 26 of the electric motors 20 and 22 are used. However, if the rotational speed sensors are not provided in the electric motors 20 and 22, the estimation is performed by the observer 34. You may do it.
In the above embodiment, the input voltages V _{set, P} , V _{set, S} of the servo amplifiers 19, 21 are used as the input of the servo pump system. Instead, the input of the servo amplifiers 19, 21 is used. The driving currents of the electric motors 20 and 22, which are state quantities having a linear relationship with the voltages V _{set, P} and V _{set, S} , may be used.

In the above embodiment, the continuously variable transmission 1 has been described based on an example in which the continuously variable transmission 1 is a belt transmission type continuously variable transmission. However, the present invention is not limited to this, and the input rotation element is an input disk, and the output rotation You may make it apply to what is called a toroidal type continuously variable transmission whose element is an output disk and whose power transmission element is the roller clamped between the input disk and the output disk.
In addition, various modifications can be made within the scope of the claims of the present invention.

The servo pump system 30 shown in the above embodiment was tested until sufficient dynamic characteristics regarding flow rate control were obtained, and the pole as a closed loop system was placed at a desired position.
As a result, the obtained dynamic characteristics are shown in FIGS. Figure 4 is a primary flow Q _P is always kept zero, the step response is applied to the secondary flow Q _S. FIG. 5 is a diagram corresponding to FIG. 4 and shows the rotation speed of the electric motor 20 of the first servo pump 15 and the rotation speed of the electric motor 22 of the second servo pump 16.

Also, FIG. 6, the secondary flow Q _S is always kept zero, the step response is applied to the primary flow Q _P. FIG. 7 is a diagram corresponding to FIG. 6 and shows the rotational speed of the electric motor 20 of the first servo pump 15 and the rotational speed of the electric motor 22 of the second servo pump 16.
When there is a request to increase the primary flow rate Q _P , the second servo pump 16 as a clamping pump sets the rotation speed of the corresponding electric motor 22 to keep the flow rate to the second hydraulic actuator 14 constant. It is increasing.

  4 to 7, it has been demonstrated that the controller of the servo pump system 30 is stable and is a non-interfering system as a multi-input multi-output system (specifically, a 2-input 2-output system). The response was also found to be fast enough to ignore the actuator dynamics.

1 is a schematic view of a vehicle equipped with a continuously variable transmission to which a flow rate control method and a flow rate control device for a servo pump according to an embodiment of the present invention are applied. It is a block diagram of a servo pump system. It is a block diagram of an observer. It is a change figure of the flow which shows the responsiveness of a flow. It is a change figure of the rotational speed of an electric motor, and respond | corresponds to the response of FIG. It is a change figure of the flow which shows the responsiveness of a flow. It is a change figure of the rotational speed of an electric motor, and respond | corresponds to the response of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Continuously variable transmission, 2 ... Engine, 3 ... Input shaft, 5 ... Output shaft, 6 ... Primary pulley (input rotation element), 7 ... Secondary pulley (output rotation element), 8 ... Belt (power transmission element), DESCRIPTION OF SYMBOLS 11 ... 1st hydraulic actuator, 14 ... 2nd hydraulic actuator, 17 ... Oil path, 17a ... Branch part, 18 ... Oil path, 19 ... 1st servo amplifier, 20 ... 1st electric motor, 21 ... 1st 2 servo amplifiers, 22 ... second electric motor, 23 ... controller, 30 ... servo pump system, 31 ... plant, 34 ... observer, 35 ... state feedback control unit, 37 ... state feedback gain multiplier, Q _P ... primary Flow rate, first servo pump flow rate, Q _{P, R} ... (primary flow rate) target flow rate, Q _S ... secondary flow rate, Q _{S, R} ... (secondary flow rate) target flow Quantity, Q _SP ... flow rate of the second servo pump, V _{set, P} ... input voltage to the first servo amplifier, V _{set, S} ... input voltage to the first servo amplifier, R1, R2 ... contact diameter, u ... input vector (input), x ... state variable vector, y ... output vector (output)

Claims (6)

The transmission ratio of the continuously variable transmission is controlled by hydraulic fluid supplied to the hydraulic actuator,
The flow rate of hydraulic oil supplied to the hydraulic actuator is controlled by a servo pump driven by an electric motor,
Using the state variable of the state variable model of the servo pump system that inputs the input voltage to the servo amplifier of the electric motor or the state quantity having a linear relationship with the input voltage, the hydraulic oil supplied to the hydraulic actuator A flow rate control method for a servo pump of a continuously variable transmission, wherein state feedback control is performed so that the flow rate becomes a target flow rate.   2. A flow rate control method for a servo pump of a continuously variable transmission according to claim 1, wherein an observer is configured using a state variable model, and the state variable is estimated by the observer. An input rotation element, an output rotation element, and a power transmission element that transmits power between the input rotation element and the output rotation element. The contact diameter of each of the input rotation element and the output rotation element with the power transmission element is determined by a hydraulic actuator. A continuously variable transmission that can change the gear ratio steplessly by changing it,
A servo pump driven by an electric motor to supply hydraulic oil to the hydraulic actuator;
A controller for controlling the servo pump,
This controller is supplied to a hydraulic actuator using a state variable of a state variable model of a servo pump system that receives an input voltage to the servo amplifier of the electric motor or a state quantity having a linear relationship with the input voltage. A flow rate control device for a servo pump of a continuously variable transmission, which has a function of state feedback control so that the flow rate of the hydraulic oil becomes a target flow rate.   4. The flow rate control device for a servo pump of a continuously variable transmission according to claim 3, wherein the controller includes an observer configured using a state variable model, and the observer estimates the state variable. In Claim 3 or 4, the input rotation element is a primary pulley of variable diameter,
The output rotating element is a variable diameter secondary pulley,
The power transmission element is a belt or a chain wound around a primary pulley and a secondary pulley,
The hydraulic actuator includes: a first hydraulic actuator for changing a contact diameter of the primary pulley with the power transmission element; and a second hydraulic actuator for changing a contact diameter of the secondary pulley with the power transmission element; Including,
The servo pump includes a first servo pump and a second servo pump,
The primary flow rate, which is the flow rate of the hydraulic oil supplied to the first hydraulic actuator, is the flow rate discharged by the first servo pump,
The secondary flow rate, which is the flow rate of the hydraulic oil supplied to the second hydraulic actuator, is a flow rate obtained by subtracting the flow rate discharged from the first servo pump from the flow rate discharged from the second servo pump. Servo pump flow control device for step transmission. In claim 5, a branch portion is provided in the middle of the oil passage connecting the second servo pump and the second hydraulic actuator,
The flow rate control device for a servo pump of a continuously variable transmission, wherein the first servo pump is disposed in an oil passage connecting the branch portion and the first hydraulic actuator.

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