JP2005269856A - Motor control device and motor control method - Google Patents

Abstract

An object of the present invention is to provide a motor control device capable of easily adjusting parameters in servo control of a two-degree-of-freedom system and realizing stable motor operation control.
In a two-degree-of-freedom motor control device including a feedback unit and a feed-forward unit, a proportional amplifier is obtained by multiplying a pseudo position command signal by a constant and a pseudo speed signal is input. The control target model circuit 12 that outputs the model speed signal ωs, the differentiation section 13 that differentiates the pseudo speed signal, and the integration section 14 that integrates the model speed signal constitute the feedforward section 10, and the feedforward signal (rf , Ωf, Trf) are output to the feedback unit 20. The feedforward unit 10 can be configured with a first-order lag system, and parameter adjustment can be easily performed.
[Selection] Figure 3

Description

  The present invention relates to a motor control device and a motor control method for controlling driving of a motor connected to a load mechanism to be driven.

In an electronic component mounting apparatus or the like, a servo motor is frequently used as a drive unit of a load mechanism that performs various work operations. These motor control devices that control the operation of the servo motor include a feed-forward control that eliminates irregular operations caused by the characteristics of the load mechanism system in addition to a feedback unit that feedback controls the rotation of the motor. 2. Description of the Related Art A two-degree-of-freedom control device with a forward unit added is known (see, for example, Patent Document 1).
JP-A-10-4692

  However, in the conventional two-degree-of-freedom motor control device, there are a plurality of parameters such as gains to be adjusted for both the feedback unit and the feedforward unit, and these parameters are necessary to realize a good control state. It was necessary to set an appropriate combination. When parameter adjustment is not performed properly, the control signal becomes oscillating, and stable motor operation control is difficult.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a motor control device that can easily perform parameter adjustment in two-degree-of-freedom servo control and can realize stable motor operation control.

  A motor control device according to the present invention is a motor control device that controls a motor that drives a load mechanism according to a position command signal generated by a command signal generating means, and detects a rotation angle and a rotation speed of the motor to detect a rotation angle signal. And a detection means for outputting a rotation speed signal, a feedforward unit for performing feedforward control of the motor by inputting the position command signal and outputting a feedforward torque signal, a feedforward speed signal, and a feedforward position signal; Position control means for inputting a compensated position command signal including the feedforward position signal as a positive element and the rotation angle signal as a negative element and outputting a temporary compensation speed command signal; the feedforward speed signal and the temporary The rotational speed signal including a compensation speed command signal as a positive element Based on a speed control means for inputting a compensation speed command signal including a negative element and outputting a temporary compensation torque command signal, and a compensation torque command signal including the feedforward torque signal and the temporary compensation torque command signal as positive elements And a feedback unit configured to control the rotational torque of the motor, and a feedback unit that feedback-controls the motor, and includes the position command signal as a positive element and the feedforward position signal as a negative element. Constant multiplying means for multiplying a position command signal by a constant to obtain a pseudo speed signal, and control target model simulating means for simulating the operation of the motor and the load unit by inputting the pseudo speed signal and outputting a model speed signal Differential means for differentiating the pseudo speed signal; and an integrating means for integrating the model speed signal. The feedforward unit is configured with the output of the differentiating means as the feedforward torque command signal, the control target model speed signal as the feedforward speed signal, and the output of the integrating means as the feedforward position signal. Output.

The motor control method of the present invention is a motor control method for controlling a motor for driving a load mechanism in accordance with a position command signal generated by a command signal generating means, and detecting a rotation angle and a rotation speed of the motor to detect a rotation angle signal. And a detection means for outputting a rotation speed signal, a feedforward unit for performing feedforward control of the motor by inputting the position command signal and outputting a feedforward torque signal, a feedforward speed signal, and a feedforward position signal; Position control means for inputting a compensated position command signal including the feedforward position signal as a positive element and the rotation angle signal as a negative element and outputting a temporary compensation speed command signal; the feedforward speed signal and the temporary The rotational speed signal including a compensation speed command signal as a positive element Based on a speed control means for inputting a compensation speed command signal including a negative element and outputting a temporary compensation torque command signal, and a compensation torque command signal including the feedforward torque signal and the temporary compensation torque command signal as positive elements And a feedback unit configured to control the rotational torque of the motor, and a feedback unit that feedback-controls the motor, and includes the position command signal as a positive element and the feedforward position signal as a negative element. Constant multiplying means for multiplying a position command signal by a constant to obtain a pseudo speed signal, and control target model simulating means for simulating the operation of the motor and the load unit by inputting the pseudo speed signal and outputting a model speed signal Differential means for differentiating the pseudo speed signal; and an integrating means for integrating the model speed signal. And using the motor control device constituting the feedforward unit, the output of the differentiating means as the feedforward torque command signal, the controlled model speed signal as the feedforward speed signal, and the output of the integrating means as the Output as feed-forward position signal.

  According to the present invention, the constant multiplying means for multiplying the pseudo position command signal including the position command signal as a positive element by a constant is used as a pseudo speed signal, and the pseudo speed signal is input to output the controlled model speed signal. The feed forward unit is configured by the controlled object model circuit that simulates the operation of the motor and the load unit, the differentiating means that differentiates the pseudo speed signal, and the integrating means that integrates the controlled object model speed signal, and the output of the differentiating means is By adopting a configuration that uses the feedforward torque command signal, the model speed signal as the feedforward speed signal, and the output of the integration means as the feedforward position signal, parameter adjustment can be easily performed and a stable motor Operation control can be realized.

  Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram of a configuration of a load mechanism of a motor control device according to an embodiment of the present invention, FIG. 2 is a block diagram showing a configuration of a control system of the motor control device of an embodiment of the present invention, and FIG. It is a block diagram which shows the transfer function of the control system of the motor control apparatus of one embodiment of this invention.

  First, a load mechanism to be controlled by the motor control device will be described with reference to FIG. FIG. 1 shows an orthogonal table mechanism used in an electronic component mounting apparatus or the like, and an X-axis table 1 and a Y-axis table 2 are linear motion mechanisms using ball screws using motors MX and MY as drive sources, respectively. . The X-axis table 1 is driven in the Y direction by the Y-axis table 2, and the work head 3 is driven in the Y direction by the Y-axis table 2. By driving the X-axis table 1 and the Y-axis table 2, the work head 3 moves in the XY direction and performs a predetermined work operation.

  The motors MX and MY are respectively driven by motor drivers 5X and 5Y of the motor controller 4 in accordance with a control command signal output from the main body control device 6, and are output from encoders EX and EY provided in the motors MX and MY during the control operation. The feedback pulse is transmitted to the motor drivers 5X and 5Y.

In the above-described load mechanism, the X-axis table 1 is driven in a cantilevered state by the Y-axis table 2, so that the control of the motor MY is easily affected by mechanical vibration during acceleration / deceleration and is stable. It is difficult to achieve high-definition control operations. In the motor control apparatus shown in the present embodiment, a configuration as described below is adopted for the purpose of stably controlling such a load mechanism.

  Next, the configuration of the motor control device will be described with reference to FIG. In FIG. 2, a command signal generation circuit 7 is a position command function of the main body control device 6 shown in FIG. 1, and a position command signal for motors MX and MY (hereinafter represented by the motor M) in the work operation by the work head 3. r is generated. The position command signal r is output to the feedforward unit 10, and the motor M of the control target unit 15 is driven according to the position command signal r.

  The control target unit 15 shows a drive system by the motor M shown in FIG. 1, and includes a detector 16 corresponding to the encoders EX and EY and a load mechanism 17 corresponding to the mechanism unit of the X-axis table 1 and the Y-axis table 2. Composed. The detector 16 is a detecting means that detects the rotation angle and rotation speed of the motor M and outputs the rotation angle signal rM and the rotation speed signal ωM.

  The feedforward unit 10 receives the position command signal r and outputs a feedforward position signal rf, a feedforward speed signal ωf, and a feedforward torque signal Trf, thereby performing feedforward control of the motor M. In the control of the motor M by the feedback unit 20 described below, the operation of the motor M is feedback controlled based on the above-described feedforward signals (rf, ωf, TRf) output from the feedforward unit 10.

  The feedback unit 20 is configured by connecting a position control circuit 21, a speed control circuit 22, and a torque control circuit 23 in series, and feedback-controls the motor M based on a feedforward signal from the feedforward unit 10. The position control circuit 21 inputs a difference signal (arrow e) between the feedforward position signal rf passed from the feedforward unit 10 and the rotation angle signal rM fed back from the detector 6, and receives a temporary compensation speed signal (arrow f). ) Is output.

  The speed control circuit 22 generates a difference signal (arrow g) between the sum signal obtained by adding the feedforward speed signal wf and the temporary compensation speed signal passed from the feedforward unit 10 and the rotational speed signal ωM fed back from the detector 6. The temporary compensation torque command signal (arrow h) is output. The torque control circuit 23 is based on a compensation torque command signal (arrow i) obtained by adding the feedforward torque signal Trf passed from the feedforward unit 10 and the temporary compensation torque command signal output from the speed control circuit 22. Is output to the motor M. Here, a proportional amplifier having a gain of 1 is used as the torque control circuit 23 (see FIG. 3).

  Therefore, the position control circuit 21 is a position control means for inputting a compensation position command signal including the feedforward position signal rf as a positive element and including the rotation angle signal rM as a negative element and outputting a temporary compensation speed command signal. The speed control circuit 22 receives the compensation speed command signal including the feedforward speed signal ωf and the provisional compensation speed command signal as positive elements and the rotation speed signal ωM as a negative element, and receives a provisional compensation torque command. This corresponds to speed control means for outputting a signal. The torque control circuit 23 serves as torque control means for controlling the rotational torque of the motor M based on a compensation torque command signal that includes both the feedforward torque signal Trf and the provisional compensation torque command signal as positive elements.

Next, the function of each part which comprises the feedforward part 10 is demonstrated. A position command signal r from the command signal generation circuit 7 is added as an integrated signal (arrow d) obtained by integrating a model speed signal, which will be described later, as a negative element, and input to the proportional amplifier 11 as a pseudo position command signal (arrow a). Is done. The proportional amplifier 11 outputs the input pseudo position command signal as a constant multiple signal (arrow b) proportional to the gain K. The constant multiple signal output here has a meaning as a pseudo speed signal and is input to the control target model circuit 12. That is, the proportional amplifier 11 is a constant multiplying unit that multiplies the pseudo position command signal including the position command signal r as a positive element by a constant number to obtain a pseudo speed signal.

  The control target model circuit 12 has a function of simulating operation responses of the motor M and the load mechanism 17 by performing calculations on the pseudo speed signal. That is, the controlled object model circuit 12 serves as controlled object model simulating means for simulating the operation of the motor M and the load mechanism 17 by inputting the pseudo speed signal and outputting the controlled object model speed signal ωs. Here, a proportional amplifier having a gain of 1 / Jm is used as the control target model circuit 12 (see FIG. 3), and a signal obtained by multiplying the pseudo speed signal by 1 / Jm is output as the model speed signal ωs.

  The model speed signal (arrow c) output from the control target model circuit 12 is integrated by the integrating unit 14 (integrating means) and output as a model position signal rs. The model position signal rs is passed to the feedback unit 20 as a feedforward position signal rf and is added as a negative element to the position command signal. Further, the output of the proportional amplifier 11 is differentiated by a differentiating unit 13 (differentiating means) and is passed to the feedback unit 20 as a feedforward torque signal Trf.

  That is, in the above configuration, the constant position multiplying means for multiplying the pseudo position command signal including the position command signal rs as a positive element by a constant number to obtain the pseudo speed signal, the differentiating means for differentiating the pseudo speed signal, and the model speed signal are integrated. The feedforward unit 10 is configured with the integrating means. The output of the differentiating means is set as the feed forward torque command signal Trf, the model speed signal ωs is set as the feed forward speed signal ωf, and the output of the integrating means is output as the feed forward position signal rf.

  Next, the control operation will be described with reference to FIG. 3 and the transfer function of the control system. As shown in FIG. 3, the proportional amplifier 11 and the control target model circuit 12 of the feedforward unit 10 are proportional elements with proportional gains of K and 1 / Jm, respectively, the differential unit 13 is a differential element, and the integration unit 14 is an integral. It is an element. The position control circuit 21, the torque control circuit 23, and the control target load unit 15 constituting the feedback unit 20 are proportional elements having proportional gains of Kp2, 1, 1 / JL, respectively. Here, JL is the moment of inertia of the control target unit 15. The speed control circuit 22 is represented by a proportional element and an integral element as Kv2 × (1 + 1 / TiS). Here, Ti is an integration time constant.

  Here, the waveform of the model position signal rs indicated by the arrow d in FIG. 3 becomes the waveform of the position signal in accordance with the position command signal r. The waveform of the signal at the arrow c is a waveform corresponding to the speed because it is a waveform obtained by differentiating the model position signal rs. Further, the waveform of the signal at the arrow b is a waveform obtained by multiplying the waveform of the signal at the arrow c by Jm, and Trf, which is a waveform obtained by differentiating the waveform by the differentiating unit 13, is a waveform corresponding to the torque.

  That is, as the feedforward signals (rf, ωf, TRf) passed from the feedforward unit 10 to the position control circuit 21, the speed control circuit 22, and the torque control circuit 23 of the feedback unit 20, as described above, the model to be controlled is used. The position signal rs, the model speed signal ωs to be controlled, and the signal obtained by differentiating the output of the proportional amplifier 11 by the differentiating unit 13 may be used.

Here, the behavior of the control system configured as described above will be described with reference to the transfer function shown in (Equation 1). Equation (1) in (Equation 1) is obtained by applying the motor rotation angle signal rM to the position command response transfer function G1 (s), the disturbance response transfer function G2 (s), the position command signal r, and the control target load unit 15. This is expressed using the acting disturbance d. Since G1 (s) and G2 (s) can be expressed by the equations (2) and (3), respectively, the two-degree-of-freedom system can separately adjust the position command response and the disturbance response. The position command response is determined by the feedforward unit 10, and the disturbance response is determined by the feedback unit 20.

  Here, considering the state in which the control target model circuit 12 of the feedforward unit 10 that simulates the operation characteristics of the control target unit 15 is appropriately set, it can be considered that Jm = JL. Then, by setting Jm = JL in the expression (3), G1 (s) is expressed in a simple form shown in the expression (4). As can be seen from the equation (4), G1 (s) corresponds to the first-order lag servo control.

  Therefore, regardless of the parameter of the feedforward unit 10, that is, the value of the gain K of the proportional amplifier 11, the feedforward torque signal Trf output to the feedback unit 20 by the feedforward unit 10 does not vibrate and is short. Good response characteristics can be obtained that converges quickly in settling time. In this case, the only parameter that needs to be adjusted in the feedforward unit 10 is the above-described gain K, so that the adjustment work can be greatly simplified.

  As described above, in the two-degree-of-freedom motor control apparatus including the feedback unit 20 and the feedforward unit 10, the hardware configuration of the control system can be simplified and the cost can be reduced by configuring the feedforward unit 10 as described above. In addition, it is possible to reduce the control load by reducing the amount of calculation during control. Further, the number of parameters that need to be adjusted can be reduced, and the adjustment work at the time of setting the control system can be easily performed.

The motor control device described above may further include a state feedback unit (not shown) that feeds back a state variable obtained by the control target model circuit 12 to the feedforward unit 10 with an appropriate gain. Here, the state variable means a variable such as the position, speed, acceleration, etc. of each mass point in the control target model circuit 12 simulating an actual load. Thereby, more stable motor operation control can be realized.

  The motor control device of the present invention has an effect that parameter adjustment can be easily performed and stable motor operation control can be realized, and is used as a driving mechanism for a load mechanism such as an electronic component mounting device. It can be used to control the operation of servo motors.

Structure explanatory drawing of the load mechanism of the motor control device of one embodiment of the present invention The block diagram which shows the structure of the control system of the motor control apparatus of one embodiment of this invention The block diagram which shows the transfer function of the control system of the motor control apparatus of one embodiment of this invention

Explanation of symbols

4 Motor Controller 5X, 5Y Motor Driver 6 Main Body Control Device 7 Command Signal Generation Circuit 10 Feedforward Unit 11 Proportional Amplifier 12 Control Target Model Circuit 13 Differentiation Unit 14 Integration Unit 15 Control Target Load Unit 20 Feedback Unit 21 Position Control Circuit 22 Speed Control Circuit 23 torque control circuit r position command signal rs model position signal ωs model speed signal rf feedforward position signal ωf feedforward speed signal Trf feedforward torque signal rM rotation angle signal ωM rotation speed signal TM motor torque signal

Claims (2)

A motor control device for controlling a motor for driving a load mechanism according to a position command signal generated by a command signal generating means,
Detecting means for detecting a rotation angle and a rotation speed of the motor and outputting a rotation angle signal and a rotation speed signal;
A feedforward unit that feedforward-controls the motor by inputting the position command signal and outputting a feedforward torque signal, a feedforward speed signal, and a feedforward position signal;
Position control means for inputting a compensated position command signal including the feedforward position signal as a positive element and the rotation angle signal as a negative element and outputting a temporary compensation speed command signal; the feedforward speed signal and the temporary Speed control means for inputting a compensation speed command signal including a compensation speed command signal as a positive element and outputting the provisional compensation torque command signal including the rotation speed signal as a negative element, the feedforward torque signal and the provisional compensation A feedback control unit configured to feedback control the motor, the torque control unit configured to control the rotational torque of the motor based on a compensation torque command signal including a torque command signal as a positive element;
Constant multiplying means for multiplying a pseudo position command signal including the position command signal as a positive element and the feedforward position signal as a negative element to obtain a pseudo speed signal by multiplying the pseudo position command signal by a constant, and a model speed by inputting the pseudo speed signal The feedforward unit includes a controlled object model simulation unit that simulates the operation of the motor and the load unit by outputting a signal, a differentiation unit that differentiates the pseudo speed signal, and an integration unit that integrates the model speed signal. Configure
The motor control device characterized in that the output of the differentiating means is the feedforward torque command signal, the controlled model speed signal is the feedforward speed signal, and the output of the integrating means is the feedforward position signal. . A motor control method for controlling a motor for driving a load mechanism according to a position command signal generated by command signal generating means,
Detection means for detecting a rotation angle and a rotation speed of the motor and outputting a rotation angle signal and a rotation speed signal; and inputting the position command signal to output a feed forward torque signal, a feed forward speed signal, and a feed forward position signal. A feedforward unit that feedforward-controls the motor, and a compensation position command signal that includes the feedforward position signal as a positive element and the rotation angle signal as a negative element. A position control means for outputting, a compensation speed command signal including the feedforward speed signal and the provisional compensation speed command signal as positive elements and the rotation speed signal as a negative element, and outputting a provisional compensation torque command signal Speed control means, the feedforward torque signal and And a feedback unit configured to control the rotational torque of the motor on the basis of a compensation torque command signal including the temporary compensation torque command signal as a positive element, and the position command signal. As a positive element and a pseudo position command signal including the feedforward position signal as a negative element by constant multiplication to make a pseudo speed signal, and input the pseudo speed signal and output a model speed signal Thus, a motor in which the feedforward unit is constituted by a controlled object model simulation unit that simulates the operation of the motor and the load unit, a differentiation unit that differentiates the pseudo speed signal, and an integration unit that integrates the model speed signal Using the control device,
The motor control method characterized in that the output of the differentiating means is the feedforward torque command signal, the controlled model speed signal is the feedforward speed signal, and the output of the integrating means is the feedforward position signal. .

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