JP2015033213A - Servo amplifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress vibration which is easy to occur when gain is switched.SOLUTION: In gain switching of a servo amplifier, at the time of gain switching, two gains to be switched in accordance with a control state are weighted to gradually perform gain switching. According to the control state of a motor, a gain switching section is provided, and a gain value in this section is calculated from values of two gains to be switched and the control state of the motor to perform gain switching. As a result, the gain value in the gain switching section becomes a transient value of two gains to be switched in accordance with the control state of the motor, and the gain switching suppressed in vibration becomes possible since the variation of gain to be switched instantly is reduced.

Description

  The present invention relates to a servo amplifier for motor drive control that performs gain switching by position control or speed control.

  Conventionally, this type of servo amplifier detects the operation mode from the absolute value of the change amount of the position command at a certain sampling time and the position command, and switches the gain for each preset operation mode by software. (For example, refer to Patent Document 1).

  FIG. 1 shows the conventional gain switching described in the patent literature. As shown in FIG. 1, the servo motor 1, the position detector 2, the motor position information 3, the position command 4, the position deviation 5, the position loop proportional gain 6, the speed command 7, and the speed detector 8. Motor speed 9, speed deviation 10, speed loop gain 11, torque command proportional component 12, speed loop integral time constant 13, torque command integral component 14, torque command 15, and current controller 16 Stop position loop gain 17, stop speed loop gain 18, stop speed loop integration time constant 19, acceleration / deceleration position loop gain 20, acceleration / deceleration speed loop gain 21, acceleration / deceleration speed It is composed of a loop integration time constant 22, a constant speed position loop gain 23, a constant speed speed loop gain 24, and a constant speed speed loop integration time constant 25.

  If the value of the position command 4 is 0 and the stop delay time has elapsed, the motor is stopped, and if the absolute value of the change amount of the position command in a certain time exceeds a certain value and the acceleration / deceleration delay time has elapsed, the motor is in an acceleration / deceleration state. If the absolute value of the change amount of the position command in a certain time is equal to or less than a certain value and a fixed speed delay time has elapsed, the motor is determined to be in a constant speed state. The value of the loop proportional gain 6, the value of the speed loop gain 18 at stop is set to the speed loop gain 11, the value of the speed loop integration time constant 19 at stop is set to the speed loop integration time constant 13, and if the motor is in the acceleration / deceleration state The value of the position loop gain 20 is set to the position loop proportional gain 6, the value of the acceleration / deceleration speed loop gain 21 is set to the speed loop gain 11, and the value of the acceleration / deceleration speed loop integration time constant 22 is set to the speed loop integration time constant 13. If the motor is in a constant speed, the value of the constant speed position loop gain 23 is set to the position loop proportional gain 6, the value of the constant speed speed loop gain 24 is set to the speed loop gain 11, and the constant speed speed loop integration time constant 25 is set. Is switched to the speed loop integration time constant 13 by software.

JP 2000-293234 A

  However, in the above-described conventional configuration, gain switching instantaneously switches the gain value when it is determined that the state of the motor has changed. Therefore, the greater the amount of change in the gain value to be switched, the more likely vibration is induced. , Had the problem of having to suppress this.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object thereof is to provide a servo amplifier characterized in that a gain value is changed according to a control state.

  In order to solve the above-mentioned conventional problems, the gain switching of the servo amplifier according to the present invention is provided with a gain switching section according to the control state of the motor. It is calculated from the control state.

  As a result, the gain value in the gain switching section becomes a transient value of the two gains that are switched according to the control state, and the amount of change in the gain that is switched instantaneously decreases, so that gain switching that suppresses vibration is possible. .

  Since the servo amplifier according to the present invention can suppress the induction of vibration due to gain switching, the speed followability can be improved and the positioning settling time can be shortened.

Conventional control block diagram Gain switching timing chart of an example in the first embodiment of the present invention Control block diagram at the time of position control in Embodiment 1 of the present invention Control block diagram at the time of speed control in Embodiment 2 of the present invention

  The first invention includes a servo motor, a position detector attached to the servo motor, a servo amplifier that receives a signal from the position detector and controls the motor, and a host controller that transmits a command to the servo amplifier. In the control system, when the servo motor is controlled from the state of the servo motor generated by the command from the host controller and the signal received from the position detector, a gain switching section is provided to switch according to the control state 2 By using a transient value of two gains as gains, the gains become gentler than instantaneous switching, speed followability can be improved, and positioning settling time can be shortened.

  In the second invention, particularly when controlling the servo motor by position control, the gain switching section of the first invention is set to gain switching according to the rotation speed of the servo motor, so that the gain is switched instantaneously. It becomes gradual, speed followability is improved, and positioning settling time can be shortened.

  In the third invention, in particular, by setting the gain switching section of the second invention as a position deviation, the gain can be made gentler than instantaneous switching, speed followability can be improved, and positioning settling time can be shortened.

  In the fourth aspect of the invention, in particular, by using the gain switching section of the second aspect as a speed command, the gain becomes gentler than instantaneous switching, speed followability can be improved, and positioning settling time can be shortened.

  In the fifth aspect of the invention, in particular, by using the gain switching section of the second aspect as a torque command, the gain can be made gentler than instantaneous switching, speed followability can be improved, and positioning settling time can be shortened.

  In the sixth aspect of the invention, in particular, when controlling the servo motor by speed control, the gain switching section of the first aspect of the invention is set to gain switching according to the speed command change amount, thereby making the gain gentler than instantaneous switching. Therefore, the speed following ability can be improved.

  In the seventh aspect of the invention, in particular, by using the gain switching section of the sixth aspect of the invention as a torque command, the gain can be made more gradual than when the gain is switched instantaneously, and the speed followability can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 2 shows a state where the motor rotation speed and the gain are switched when the gain is switched in the first embodiment of the present invention.

  In FIG. 2, the gain switching of the present invention is represented by a solid line, and portions different from the present invention by conventional gain switching are represented by a dotted line.

  In the conventional gain switching, at the time of acceleration, when the motor rotation speed 9 reaches the motor rotation speed H28, the first position loop gain 30 is instantaneously changed to the second position loop gain 31, and the first speed loop gain 32 is changed to the second speed. The loop speed 33 is switched from the first speed loop integration time constant 34 to the second speed loop integration time constant 35, and at the time of deceleration, the second position loop gain is instantly reached when the motor rotational speed 9 reaches the motor rotational speed L27. From 31, the first position loop gain 30 is switched, from the second speed loop gain 33 to the first speed loop gain 32, and from the second speed loop integration time constant 35 to the first speed loop integration time constant 34. At this time, since the gain is switched instantaneously, depending on the difference between the gain values to be switched, the acceleration changes abruptly until the gain is switched and after the gain is switched. The gain switching timing is the motor rotation speed H28 during acceleration, and the motor rotation speed L27 during deceleration. Hysteresis is given to the gain switching timing during acceleration and deceleration.

  In the present invention, a gain switching section 26 is provided, and is set between the motor rotation speed L27 and the motor rotation speed H28 for comparison with the conventional gain switching. During acceleration, during the period from when the motor rotational speed 9 reaches the motor rotational speed L27 to the motor rotational speed H28, the first position loop gain 30 changes from the first position loop gain 31 to the second position loop gain 31. The two-speed loop gain 33 is switched from the first speed loop integration time constant 34 to the second speed loop integration time constant 35 by taking a transient gain value. During deceleration, the second position loop gain 31 changes from the second position loop gain 31 to the first position loop gain 30 and the second speed loop gain 33 changes from the second speed loop gain 33 to the first position loop gain 30 between the time when the motor speed 9 reaches the motor speed H28 and the motor speed L27. The first speed loop gain 32 is switched from the second speed loop integration time constant 35 to the first speed loop integration time constant 34 by taking a transient gain value. The gain value during this period is calculated by weighting two gains that are switched depending on where the motor rotation speed 9 is located between the motor rotation speed L27 and the motor rotation speed H28. Note that the gain value during this period is not only linearly changed as shown in FIG. 2, but also by a calculation method for calculating an appropriate value depending on the characteristics of the controlled object. As a result, the gain in the gain switching section becomes a transient value of the two gains to be switched, and the change in acceleration is thereby moderated, so that the induction of vibration can be suppressed. As a result, the speed following performance is improved as compared with the conventional case, and the position settling time can be shortened.

(Embodiment 2)
FIG. 3 shows a control block diagram in the position control in the second, third, fourth, and fifth embodiments of the present invention.

In FIG. 3, the controlled object 29 is operated by the servo motor 1. The position detector 2 detects motor position information 3 of the servo motor 1. A position deviation 5 is generated from the difference between the position command 4 and the motor position information 3, and a speed command 7 is generated by applying a position loop proportional gain 6 thereto. A motor rotation speed 9 is generated from the motor position information 3 by the speed detector 8, and a speed deviation 10 is generated from the difference between the speed command 7 and the motor rotation speed 9. A torque command 15 is generated from a torque command proportional component 12 having a speed loop gain 11 applied thereto and a torque command integral component 14 having a speed loop integral time constant 13 applied thereto. This is output to the current controller 16 to constitute a control system for operating the servo motor 1.

  The operation and action of gain switching by position control configured as described above will be described below.

  First, when performing gain switching according to the motor rotation speed, the gain switching section is defined by two motor rotation speeds. When the motor rotation speed is within the range of the gain switching section, the gain value is calculated by weighting the two gains to be switched depending on where the motor rotation speed is located in the gain switching section. The target gains at this time are position loop proportional gain, velocity loop proportional gain, and velocity loop integral time constant.

  As described above, in this embodiment, the gain is switched according to the motor rotation speed, and the gain value in the gain switching section is set to a transient value of the two gains, thereby controlling the servo motor control state. Therefore, the vibration due to gain switching can be suppressed.

  In this embodiment, the gain switching timing at the time of acceleration and deceleration in the conventional mode is set to the gain switching interval, so that the gain switching is performed at an earlier stage than the conventional one, speed followability is improved, and position settling is improved. The tact time can be shortened.

  In addition, although the gain switching section of the present embodiment is the motor rotation speed, by making this a position deviation or speed command or torque command, by performing gain switching according to the characteristics of the controlled object, more stable Control can be performed.

(Embodiment 3)
FIG. 4 shows a control block diagram in the speed control in the sixth and seventh embodiments of the present invention.

  In FIG. 4, the controlled object 29 is operated by the servo motor 1. The position detector 2 detects motor position information 3 of the servo motor 1. The speed command change amount 36 is a change amount of the speed command 7 in a certain sampling time. A motor rotation speed 9 is generated from the motor position information 3 by the speed detector 8, and a speed deviation 10 is generated from the difference between the speed command 7 and the motor rotation speed 9. A torque command 15 is generated from a torque command proportional component 12 having a speed loop gain 11 applied thereto and a torque command integral component 14 having a speed loop integral time constant 13 applied thereto. This is output to the current controller 16 to constitute a control system for operating the servo motor 1.

  The operation and action of gain switching by speed control configured as described above will be described below.

  First, when performing gain switching according to the speed command change amount, the gain switching section is defined by two speed command change amounts. When the speed command change amount is in the range of the gain switching section, the gain value is calculated by weighting the two gains to be switched depending on where the speed command change amount is located in the gain switching section. The target gains at this time are the speed loop proportional gain and the speed loop integration time constant.

  As described above, in the present embodiment, the gain is switched according to the speed command change amount, and the control value of the servo motor is obtained by setting the two gains in the gain switching section as transient values. Therefore, the vibration due to gain switching can be suppressed.

  In this embodiment, the gain switching timing at the time of conventional acceleration and deceleration is set as the gain switching section, so that the gain switching is performed from an earlier stage than the conventional one, and the speed followability can be improved.

  Moreover, although the gain switching section of this embodiment is used as a speed command change amount, by using this as a torque command, more stable control can be performed by performing gain switching according to the characteristics of the controlled object. it can.

  As described above, the servo amplifier according to the present invention can improve the speed tracking performance or shorten the positioning settling time by providing the gain switching section and performing the gain switching transiently according to the control state. Therefore, it can be applied to uses such as processing, assembly, and conveyance that require gain switching.

1 Servo Motor 2 Position Detector 3 Motor Position Information 4 Position Command 5 Position Deviation 6 Position Loop Proportional Gain 7 Speed Command 8 Speed Detector 9 Motor Rotational Speed 10 Speed Deviation 11 Speed Loop Gain 12 Torque Command Proportional Component 13 Speed Loop Integration Time Constant 14 Torque command integral component 15 Torque command 16 Current controller 17 Stop position loop gain 18 Stop speed loop gain 19 Stop speed loop integral time constant 20 Acceleration / deceleration position loop gain 21 Acceleration / deceleration speed loop gain 22 Acceleration / deceleration Time loop integral time constant 23 Position loop gain at constant speed 24 Speed loop gain at constant speed 25 Speed loop integral time constant at constant speed 26 Gain switching section 27 Motor rotation speed L
28 Motor rotation speed H
29 Control Target 30 First Position Loop Gain 31 Second Position Loop Gain 32 First Speed Loop Gain 33 Second Speed Loop Gain 34 First Speed Loop Integration Time Constant 35 Second Speed Loop Integration Time Constant 36 Speed Command Change

Claims (7)

In a servo amplifier comprising a motor, a position detector attached to the motor, a servo amplifier that receives a signal from the position detector and controls the motor, and a host controller that transmits a command to the servo amplifier, A gain switching section is provided when controlling the motor based on the command from the host controller and the state of the motor generated by the signal received from the position detector, and two gains to be switched according to the control state of the motor. Servo amplifier whose gain is a transient value. The servo amplifier according to claim 1, wherein when the motor is controlled by position control, the gain is switched according to the rotational speed of the motor. The servo amplifier according to claim 1, wherein when the control of the motor is performed by position control, the gain is switched according to the position deviation of the motor. The servo amplifier according to claim 1, wherein when the motor is controlled by position control, the gain is switched according to a speed command to the motor. The servo amplifier according to claim 1, wherein when the motor is controlled by position control, the gain is switched in accordance with a torque command to the motor. The servo amplifier according to claim 1, wherein when the motor is controlled by speed control, the gain is switched in accordance with a speed command change amount to the motor. The servo amplifier according to claim 1, wherein when the motor is controlled by speed control, the gain is switched in accordance with a torque command to the motor.

Images