JP5217033B2 - Information processing system and information processing method for encoder - Google Patents

Description

  The present invention relates to an information processing system and an information processing method for an encoder that detects an absolute value of a displacement of a movable object.

  2. Description of the Related Art Conventionally, a magnetic encoder is known as a device that detects the amount of displacement of a movable object to be detected and the absolute value of the displacement. For example, as one aspect of the magnetic encoder, one pole pair of magnets is rotated, the magnetic field change is detected by an MR element, and the obtained Sin signal and Cos signal are AD-converted into a microcomputer, There is one that detects an absolute value of a rotational position of a magnet by calculating an arc tangent signal and using the arc tangent signal (for example, Patent Document 1).

  Such a sampling period on the magnetic encoder side may be uniquely created by a timer built in the microcomputer. On the other hand, there is a case where the microcomputer side of the host device that uses position information from the magnetic encoder performs serial communication with a unique sampling period to exchange data. In such a case, in order to appropriately estimate the actual position of the movable object to be detected, it is necessary to set both sampling periods to the same time.

JP 2000-65596 A

  However, when the sampling cycle of the microcomputer on the magnetic encoder side and the microcomputer on the host device side are different, it is difficult to estimate the actual position of the movable object. Specifically, the processing time (absolute value calculation time) on the magnetic encoder side is almost constant, but if the data read timing by the microcomputer on the host device side is not synchronized with the sampling cycle on the magnetic encoder side, When the apparatus side receives the position information, the actual position of the movable detection object and the delay time of the read data are not constant. As a result, it becomes difficult to estimate the actual position of the movable object to be detected from the output data of the magnetic encoder, instead of the data having a certain group delay from the actual rotational position at the time of sampling. In particular, even if the sampling cycle is set to be the same on the magnetic encoder side and the host device side, it is difficult to make this exactly the same due to the frequency error of the clock generation circuit, and the same problem as described above may occur. There is.

  The present invention has been made in view of these points, and its purpose is to estimate the actual position of the movable object more accurately even when the sampling period differs slightly between the encoder and the host device. It is an object to provide an information processing system and an information processing method for an encoder that can be used.

  In order to solve the above problems, the present invention provides the following.

(1) A sine wave A phase signal output from the A phase sensor in response to the displacement of the movable object to be detected, and a sine wave B to be output from the B phase sensor in response to the displacement of the movable object to be detected. And an encoder that outputs an absolute value of the displacement of the movable object by analyzing the phase signal, and a host device that transmits a data request signal indicating a data request for the absolute value to the encoder. In the information processing system of the encoder, the higher-level device transmits the data request signal based on the calculation time for calculating the absolute value in the encoder, and the encoder is triggered by reception of the data request signal. After calculating the absolute value, the host device transmits the data request signal and then completes the calculation of the absolute value in the encoder. An information processing system for an encoder , wherein the next data request signal is transmitted before the sampling period elapses .

  According to the present invention, an encoder that analyzes a sine wave A-phase signal and a B-phase signal and outputs an absolute value of the displacement of the movable object to be detected, and a host device that transmits a data request signal to the encoder; When transmitting a data request signal, the host device transmits the data request signal based on the calculation time for calculating the absolute value of the displacement of the movable object. On the other hand, the encoder starts calculating the absolute value when receiving the data request signal. As a result, the time lag between the actual position of the movable object to be detected and the output position of the calculation result is substantially constant, that is, a constant group delay, and as a result, the actual position of the movable object to be detected can be estimated more accurately. . In particular, even if the sampling cycle is not the same between the encoder side microcomputer and the host unit side microcomputer due to the frequency error of the clock generation circuit, the actual position of the movable object can be estimated more accurately in the same way. can do.

  Here, “based on the computation time” is to determine the transmission timing of the data request signal sent from the host device to the encoder. For example, if the computation time T is known, the previous data request signal It may be immediately after the time T has elapsed since the transmission of, or after the time T + α (considering the serial communication time between the encoder and the host device) has elapsed since the transmission of the previous data request signal. It may be after the time T + α + β (considering a predetermined waiting time) has elapsed since the signal transmission.

  Further, “when triggered by reception of a data request signal” determines the start timing of the absolute value calculation processing in the encoder, and may be, for example, simultaneously with reception of the data request signal, It may be after a certain time (arbitrary fixed time) has elapsed since the reception of the request signal.

  The encoder outputs an “absolute value of displacement”, but the output mode is not limited. For example, the signal may be converted into a pulse signal through a pulse generation circuit, or a signal indicating an absolute value may be output through another conversion circuit.

Further, in the encoder information processing system according to the present invention, the host device transmits the data request signal, and after the calculation of the absolute value in the encoder is completed, before the sampling period elapses, A data request signal is transmitted.

  According to the present invention, the above-described host device transmits the next data request signal after transmitting the data request signal and before the sampling period elapses after the calculation of the absolute value in the encoder is completed. Therefore, the actual position of the movable detection object can be estimated more accurately while reducing the waiting time on the encoder side (or reducing it to 0) and preventing the control cycle of the entire system from being prolonged.

( 2 ) The information processing system for an encoder, wherein the host device transmits the next data request signal after receiving the absolute value from the encoder after transmitting the data request signal.

  According to the present invention, since the above-described host apparatus transmits the data request signal and then transmits the next data request signal after receiving the absolute value from the encoder, the displacement of the movable object to be detected is determined. It is possible to more accurately estimate the actual position of the movable detection object while preventing a software error (runaway) caused by repeated interruption processing (for example, by a REQ signal) during the absolute value calculation processing.

( 3 ) The encoder information processing system, wherein the movable object to be detected is a permanent magnet in which a pair of S and N poles are magnetized.

  According to the present invention, since the above-mentioned movable object to be detected is a permanent magnet with a pair of S and N poles magnetized, the absolute value of the displacement of the pair of magnetized permanent magnets is detected. Even in this case, the actual position of the movable object can be estimated more accurately. In particular, a single pole pair magnetic encoder has a simple mechanical structure compared to a multipole magnetic encoder. Therefore, it is easy to cope with downsizing while reducing the mechanical cost. On the other hand, circuit cost tends to increase. Even in such a case, according to the encoder information processing system of the present invention, it is only necessary to adjust the transmission timing of the data request signal and the start timing of the absolute value calculation process. Thus, the actual position of the movable object can be estimated more accurately without increasing the circuit cost.

( 4 ) A sinusoidal A-phase signal output from the A-phase sensor corresponding to the displacement of the movable object to be detected and a sinusoidal B output from the B-phase sensor corresponding to the displacement of the movable object to be detected. In the information processing method of the encoder for calculating the absolute value of the displacement of the movable object by analyzing the phase signal, a data request signal indicating a data request for the absolute value is sent from the host device to the encoder. The steps to be sent,
In response to the reception of the data request signal, the absolute value calculation process is started in the encoder, and the host device transmits the data request signal and then transmits the absolute value in the encoder. And a step of transmitting a next data request signal before the sampling period elapses after the calculation is completed .

  According to the present invention, in an information processing method for an encoder that analyzes a sinusoidal A-phase signal and a B-phase signal and calculates an absolute value of a displacement of a movable object, absolute value data is transmitted from a host device to the encoder. A step of transmitting a data request signal indicating a request and a step of starting an absolute value calculation process in the encoder triggered by the reception of the data request signal. The time lag between the actual position and the output position of the calculation result can be made almost constant, and as a result, the actual position of the movable detection object can be estimated more accurately.

  According to the present invention, the timing at which the data request signal is transmitted from the host device to the encoder and the timing at which the encoder starts calculating the absolute value are adjusted. The time difference from the output position can be made substantially constant (constant group delay), and as a result, the actual position of the movable detection object can be estimated more accurately.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram showing a hardware configuration of an information processing system of an encoder 1 according to an embodiment of the present invention. In particular, FIG. 1A shows an outline of the hardware configuration, and FIG. 1B shows an image diagram of the hardware configuration.

  As shown in FIGS. 1A and 1B, the encoder 1 includes an MR element (MR Element) 10 and a microcomputer 20. The Cos signal and Sin are sent from the MR element 10 to the microcomputer 20. A signal is input. More specifically, the MR element 10 outputs an A-phase sensor that outputs a sinusoidal Sin signal corresponding to the displacement of the movable object and a sinusoidal Cos signal corresponding to the displacement of the movable object. And a B-phase sensor for output.

  In the present embodiment, a permanent magnet 50 in which a pair of S and N poles is magnetized is used as the “movable object” (see FIG. 1B). In FIG. 1A, only the MR element 10 that is one component of the A-phase sensor and the B-phase sensor is shown. However, for example, a rectifier circuit, a low-pass filter, a differential amplification amplifier, and an MR element 10 are used. A phase sensor and a B phase sensor are constituted by various electric elements such as a driver for supplying an exciting current to the A phase sensor.

  The microcomputer 20 has an electrical element such as an Interpolator or an RS422 driver (may be an Open Collector), but may have any other element. Further, as shown in FIG. 1A, an A / D conversion circuit (ADC 21) is provided, and the analog signal is digitized by the ADC 21. Although not particularly shown in FIG. 1, the microcomputer 20 has various electric elements such as a CPU, a ROM, and a RAM, and has a function of calculating the absolute value of the displacement of the movable object. That is, the storage medium such as the ROM stores various programs such as a program for comprehensively controlling the entire encoder 1 and a program for calculating the absolute value of the displacement of the movable detection object. And the arithmetic processing is executed while using the RAM as a working area. As described above, the microcomputer 20 calculates the absolute value of the displacement of the permanent magnet 50 by analyzing the A-phase signal (Sin signal) and the B-phase signal (Sin signal and a Cos signal having a phase difference of π / 2). It has a function to do. Although not shown in FIG. 1, the microcomputer 20 has a pulse generation circuit and outputs the calculated absolute value as a pulse signal.

  On the other hand, the host device 30 includes a microcomputer 31 that transmits a data request signal indicating an absolute value data request to the encoder 1. The microcomputer 31 also has a CPU, It has various electric elements such as ROM and RAM. That is, various programs such as a transmission program for transmitting a data request signal to the encoder 1 are stored in a storage medium such as a ROM. The CPU reads these programs as appropriate, and uses the RAM as a working area. Execute the transmission process.

  Here, in the information processing system of the encoder 1 according to this embodiment, the transmission timing of the data request signal transmitted from the higher-level device 30 to the encoder 1 and the absolute value calculation start timing executed by the encoder 1 are used. There are features. Hereinafter, it demonstrates concretely using FIGS.

  FIG. 2 is an explanatory diagram for explaining a comparison between the information processing system of the encoder 1 according to the present embodiment and a conventional system. FIG. 2A shows a conventional system, and FIG. 2B shows an information processing system according to the present embodiment.

In FIG. 2A, on-demand is not adopted, that is, in the conventional system in which the encoder 1 performs its own arithmetic processing without receiving the data request signal from the host device 30, the encoder 1 (the microcomputer 20) Output period (sampling period) and the sampling period of the host apparatus 30 (the microcomputer 31) on the side of reading the encoder 1 are determined independently. Therefore, even if the calculation time for calculating the absolute value in the encoder 1 is constant, it is not a constant delay when viewed from the host device 30 side. For example, as shown in FIG. 2 (a), the upper device 30 is the time of sending the first data request signal is delayed from the output timing of the encoder 1 by the delay time D _1. Then, when the upper device 30 transmits the next data request signal is delayed by a delay time D ₂ from the output timing of the encoder 1. Similarly, delays D ₃ , D ₄ , D ₅ , D ₆ , and D ₇ are generated. In the conventional system, since these delay times D _{1 to} D ₇ are not constant, it is difficult to obtain the actual position (rotational position) of the permanent magnet 50.

  On the other hand, as shown in FIG. 2B, on-demand is adopted, that is, the encoder 1 starts the calculation of the absolute value after receiving the data request signal from the host device 30. According to the information processing system according to the embodiment, the host device 30 (the microcomputer 31 thereof) transmits the data request signal based on the calculation time for calculating the absolute value in the encoder 1. Specifically, when the fixed time obtained by adding the serial communication time between the encoder 1 and the host device 30 to the calculation time is defined as C, the host device 30 gives the fixed time C some time delay. The data request signal is transmitted above (in this embodiment, in synchronization with the processing cycle of the encoder 1). Then, the encoder 1 (the microcomputer 20 thereof) starts calculating the absolute value in response to the reception of the data request signal from the host device 30 (at the same time as reception). Thus, by starting the computation on the encoder 1 side on demand, a fixed delay (fixed time C) corresponding to the computation time occurs on the host device 30 side. However, if the group delay is constant, The actual position (rotational position) of the permanent magnet 40 can be easily estimated.

  The manner in which the actual position (rotational position) of the permanent magnet 40 is estimated will be further described in detail with reference to FIG. FIG. 3 is an explanatory diagram for explaining how the actual position of the permanent magnet 50 is estimated.

As shown in FIG. 3, when the absolute value calculation process is performed in the encoder 1 using the microcomputer 20, a deviation occurs between the actual position at the time of sampling and the actual position at the end of the calculation. For example, when the first data request signal is transmitted and sampled at the time point X ₁ and the calculation end time point X ₂ , a deviation of L ₁ occurs in the rotational position (actual position) of the permanent magnet 50. Similarly, when the next data request signal is transmitted and sampled at the time point Y ₁ and the calculation end time point Y ₂ , the rotational position (actual position) of the permanent magnet 50 is shifted by L ₂ . In the example shown in FIG. 3, L ₁ ≠ L ₂ , but the permanent magnet 50 starts to move for a while and then rotates at a constant speed (because the graph becomes a straight line that rises to the right). approaching to ₁ = _{L 2.} Then, since the microcomputer processing time is substantially constant (see the fixed time C in FIG. 2B), only the group delay occurs as a whole (that is, it can be easily corrected), and the permanent magnet 50 The actual position can be easily estimated. In this regard, when the delay time is not constant as in the conventional system (see the delay times D _{1 to} D _{7 in} FIG. 2A), even if the permanent magnet 50 rotates at a constant speed, the group delay It cannot be corrected easily.

  Next, the transmission timing of the data request signal will be described in detail. 4 shows a state in which the transmission timing of the data request signal is optimum, FIG. 5 shows a state in which the transmission timing of the data request signal is late, and FIG. 6 shows a state in which the transmission timing of the data request signal is early. Show.

  As shown in FIG. 4, when the transmission cycle (request cycle) of the data request signal (REQ signal) from the higher-level device 30 is the same as the processing cycle of the encoder 1, the optimal transmission timing is obtained. This is because there is no waiting time (see FIG. 5) and no software error occurs (see FIG. 6). “Calculation processing” in the figure indicates calculation time for calculating an absolute value in the encoder 1, and “communication” indicates serial communication time between the host device 30 and the encoder 1.

  As shown in FIG. 5, if the request cycle of the host device 30 is longer than the processing cycle of the encoder 1, the shaded portion in the figure becomes a waiting time for the encoder 1 to do nothing, and control of the entire system The cycle becomes longer. Furthermore, if the permanent magnet 50 of the encoder 1 rotates more than one rotation (in electrical angle) during the request cycle of the host device 30, the position becomes unknown.

  Therefore, in order to prevent the position from being lost, the maximum value of the request cycle may be determined based on the number of rotations used by the encoder 1. Further, as shown in FIG. 4, after the data request is transmitted, the next data request signal is transmitted at the same time as the sampling period (encoder processing period) of the encoder 1 elapses (or before the sampling period elapses). That's fine. Thereby, it can prevent that the control period of the whole system becomes long.

  Note that, even at the transmission timing shown in FIG. 5, since the encoder 1 can operate in synchronization with the data request signal (REQ signal), the performance of the microcomputer 31 on the host device 30 side is low and the processing time is long. Can also be supported. In this respect, there is an advantage that the other microcomputer (microcomputer 31) is not selected as the encoder 1.

  Next, as shown in FIG. 6, if the request cycle of the host device 30 is shorter than the processing cycle of the encoder 1, there is a possibility that a software error (runaway) may occur. More specifically, since the calculation process of the encoder 1 (absolute value) starts by the data request signal (REQ signal), the calculation result ends when the REQ signal is given in a cycle shorter than the encoder processing time. Therefore, the communication process cannot be performed (see the cross in FIG. 6). Therefore, no answer is returned for the REQ signal. Further, since the interrupt process is performed by the REQ signal on the microcomputer 20 side of the encoder 1, the multiple interrupt process is executed as a result, which may cause a software error (runaway).

  Therefore, as shown in FIG. 4, after transmitting a data request and receiving an absolute value from the encoder 1, the next data request signal may be transmitted. Thereby, the software error mentioned above can be prevented.

  As described with reference to FIGS. 4 to 6, the appropriate transmission timing of the data request signal (the timing for eliminating the waiting time and preventing the software error) is, after the host device 30 transmits the data request signal, This is after the host device 30 receives the absolute value from the encoder 1 and before the sampling period of the encoder 1 elapses. The optimum transmission timing is when the transmission cycle of the data request signal (REQ signal) from the higher-level device 30 is the same as the processing cycle of the encoder 1, as shown in FIG.

[Main effects of the embodiment]
As described above, according to the information processing system and information processing method of the encoder 1 according to the present embodiment, the encoder is received on demand after receiving the data request signal from the counterpart microcomputer (the microcomputer 31 of the host device 30). The calculation process (absolute value calculation process) on the first side is started. That is, a data request signal indicating an absolute value data request (of the rotational position of the permanent magnet 50) is transmitted from the host device 30 to the encoder 1, and then the data request signal is received in the encoder 1 as a trigger. The absolute value calculation process is started. As a result, the processing on the encoder 1 side is performed in synchronization with the sampling cycle of the counterpart microcomputer, and the time delay from the actual position is only the processing time of the encoder 1 when the counterpart microcomputer receives the data. It becomes a fixed time (a group delay of a fixed time). As a result, the delay time is known, and the actual position can be estimated more accurately (and easily).

  Further, as described above, by transmitting the next data request signal before the sampling period of the encoder 1 elapses, the actual position of the permanent magnet 50 can be set while preventing the control period of the entire system from being prolonged. It can be estimated more accurately, and after receiving the absolute value from the encoder 1, the next data request signal is transmitted to prevent a software error (runaway) due to repeated interrupt processing, and permanently The actual position of the magnet 50 can be estimated more accurately. Furthermore, if the present invention is applied when the movable object to be detected is the permanent magnet 50, the actual position of the permanent magnet 50 can be estimated more accurately while suppressing an increase in circuit cost.

  If the microcomputer 20 is in the sleeve state during the waiting state until the on-demand signal (data request signal) of the counterpart microcomputer (microcomputer 31) is sent, a power saving design can be achieved. In this case, the on-demand signal may be used for triggering the return from sleep and starting computation.

  When the present invention is applied to a multi-rotation absolute value encoder, when power is not supplied from the host device 30 side, multi-rotation unit data is updated by battery drive. The update cycle of only the multi-rotation part data may be a sampling cycle longer than normal processing. In the on-demand system, the original absolute value calculation only needs to be performed when data is requested from the other party, thus saving power and extending battery life.

  The information processing system and information processing method of the encoder 1 according to the present invention are useful as those capable of estimating the actual position of the movable object more accurately.

It is a block diagram which shows the hardware constitutions of the information processing system of the encoder which concerns on embodiment of this invention. It is explanatory drawing for demonstrating the comparison with the information processing system of the encoder which concerns on this embodiment, and the conventional system. It is explanatory drawing for demonstrating a mode that the real position of a permanent magnet is estimated. It is a figure which shows a mode that the transmission timing of a data request signal is optimal. It is a figure which shows a mode that the transmission timing of a data request signal is late. It is a figure which shows a mode that the transmission timing of a data request signal is early.

Explanation of symbols

1 Encoder 10 MR element 20 Microcomputer 21 ADC
30 Host device 31 Microcomputer 50 Permanent magnet

Claims (4)

A sinusoidal A-phase signal output from the A-phase sensor corresponding to the displacement of the movable detection object, and a sine-wave B-phase signal output from the B-phase sensor corresponding to the displacement of the movable detection object And an encoder that outputs an absolute value of the displacement of the movable detection object and a host device that transmits a data request signal indicating a data request for the absolute value to the encoder. In the processing system,
The upper device transmits the data request signal based on the calculation time for calculating the absolute value in the encoder,
The encoder starts the calculation of the absolute value triggered by the reception of the data request signal ,
The encoder, wherein the host device transmits the next data request signal after the data request signal is transmitted and before the sampling period elapses after the calculation of the absolute value in the encoder is completed. Information processing system. The host system, the from the transmission of the data request signal, after receiving the absolute value from the encoder, the encoder information processing system according to claim 1, wherein the transmitting the next data request signal. 3. The information processing system for an encoder according to claim 1, wherein the movable object to be detected is a permanent magnet in which a pair of S and N poles are magnetized. A sinusoidal A-phase signal output from the A-phase sensor corresponding to the displacement of the movable detection object, and a sine-wave B-phase signal output from the B-phase sensor corresponding to the displacement of the movable detection object In the information processing method of the encoder that calculates the absolute value of the displacement of the movable object by analyzing
A step of transmitting a data request signal indicating a data request for the absolute value from the host device to the encoder;
Triggered by the reception of the data request signal, the encoder starts calculating the absolute value in the encoder;
In the host device, after the data request signal is transmitted, the next data request signal is transmitted before the sampling period elapses after the calculation of the absolute value in the encoder is completed;
An information processing method for an encoder, comprising:

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