JP2011147201A - Electric motor control apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric motor control apparatus for obtaining a stable control response by continuously adjusting a control parameter to an optimum value even if a speed pattern, a load, or the like fluctuates in actual operation. <P>SOLUTION: The electric motor control apparatus includes an automatic operation command generation unit 4 for output of a command pattern such as an acceleration/deceleration pattern for a state quantity of an electric motor, a position/speed adjustment unit 5 for feeding back the state quantity to perform control for following the command pattern, and a control parameter operation unit 33 for changing a control parameter in the adjustment unit 5 based on the state quantity. In the electric motor control apparatus, a parameter operation unit 33 adjusts the control parameter to an optimum value while the electric motor drives a load machine, and the command pattern changes according to the state of the load machine. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a control device for an electric motor that drives a load machine, and more particularly to an electric motor control device including self-tuning means for optimizing control parameters such as a position adjustment gain and a speed adjustment gain.

  As a conventional technology of this type, in a motor control device that constitutes a position feedback loop and a speed feedback loop by a microcomputer, for example, an overshoot amount, a rise time, and a vibration component of a response waveform related to a state quantity such as the speed and position of the motor A method of self-tuning control parameters while observing the above has been proposed.

FIG. 4 is a block diagram of a conventional servo motor control device to which this type of self-tuning method is applied, and is described in Patent Document 1. In FIG.
4, 100 converts a microcomputer, and control unit comprising self-tuning means, 114 digital outputs of the control unit 100 (current command value) I _r the current command value I _s of the analog signals D / a converter, 118c subtracter for obtaining the difference ΔI between the current command value _{I s} and the current detection value _{I d,} the power amplifier 117, 111 is the resistance for current detection, 110 motor to be controlled, the 115 The position detector attached to the electric motor 110 is shown.

In the control unit 100, 116 command generator for outputting the position command value _{L s,} 118a subtracter for obtaining the difference ΔL between the detected position value _{L d} between the position command value _{L s,} 119 is the deviation ΔL zero position control unit for calculating a velocity command value V _r such that, 118b subtracter for obtaining the difference ΔV between the speed command value V _r and the speed detection value V _d, 112 a current command value such that the deviation ΔV to zero speed control unit for calculating the I _r, 120 is a position counter for calculating the position detection value _{L d} from the output of the position detector 115, 121 speed calculator for similarly calculating the velocity detection value _{V d,} 122 a position control section 119 The parameter change determination unit outputs a control parameter change instruction signal such as a position response, a rise time of the speed response, and an overshoot amount to the speed control unit 112.

In the above configuration, speed feedback loop is provided inside the position feedback loop of the motor 110, further on the inner side, the current of the motor 110 (torque) feedback loop is provided, the current current detection value I _d of the electric motor 110 the speed detection value V _d to match the speed command value V _r with match the command value I _s, ultimately, control line such as to match the position detection value L _d of the motor 110 to the position command value L _s Is called.

Here, the parameter change determination unit 122 gradually increases the gains of the speed control unit 112 and the position control unit 119 when an instruction signal indicating the self-tuning mode is input from the command generation unit 116. Then, when it is detected that consisted frequency components of the position detection value L _d in oscillation state, calculates the control target gain using the gain of the oscillation frequency and the speed control unit 112 and the position control unit 119, the speed control unit 112 Is changed from proportional control to proportional-integral control, and each gain is increased again. Thereafter, when the oscillation state is detected again, the gains are gradually lowered until the oscillation phenomenon is settled.
With this operation, each gain when the speed response and position response rise time and overshoot amount fall within the specified range and when the oscillation phenomenon falls can be adjusted to the optimum value, and then the self-tuning mode An end signal is sent to the command generator 116.

JP-A-3-122701 (page 3, lower right column, line 20 to page 4, upper right column, line 16, FIG. 1, FIG. 2, etc.)

In the above-described conventional technology, the parameter change determination unit 122 is based on the position command value L _s of the electric motor 110 with respect to control parameters such as the gain of the position control unit 119 and the speed control unit 112 while the electric motor 110 is being driven. A self-tuning operation is performed, and the control parameter is adjusted to the optimum value by measuring the overshoot amount and rise time of the response waveform, the oscillation frequency intentionally oscillated, and the like.
However, in this self-tuning means, the pattern (command pattern) of the position command value L _s output from the command generation unit 116 at the time of tuning is a pattern fixed so as to reciprocate the motor 110 at a constant speed, for example. ing. For this reason, there is a possibility that the control parameter cannot be adjusted to the optimum value when the command pattern changes during actual operation or when a load fluctuation occurs.

  Therefore, the problem to be solved by the present invention is to provide a motor control device that can stably adjust the control parameter to an optimum value and obtain a stable control response even when a command pattern changes or a load fluctuation occurs during actual operation. Is to provide.

  In order to solve the above-described problem, the invention according to claim 1 is directed to a command generation unit that outputs a command pattern related to a state quantity of an electric motor, and an adjustment unit that controls the state quantity to be fed back to follow the command pattern. An electric motor control device that adjusts the control parameter to an optimum value by the parameter operating means while driving a load machine by the electric motor. The command pattern is changed according to the state of the load machine.

  The invention according to claim 2 is the electric motor control device according to claim 1, wherein the acceleration / deceleration component in the command pattern is changed stepwise.

  According to a third aspect of the present invention, in the electric motor control device according to the first or second aspect, a desired follow-up to the command pattern is performed in the control parameters tuned by changing the command pattern stepwise. The control parameter that provides the best response and the lowest control response is selected as the optimum value.

  According to the present invention, the control parameters such as the position adjustment gain and the speed adjustment gain are tuned by changing the acceleration component and the like of the command pattern, and a control parameter that provides a stable control response is selected as an optimum value. Even when the acceleration / deceleration component of the command pattern changes or the load fluctuates during actual operation, the control loop does not become unstable and a highly robust control response can be realized.

It is a block diagram which shows the internal structure of the electric motor control apparatus which concerns on embodiment of this invention. It is a flowchart of the self-tuning operation in the embodiment of the present invention. It is explanatory drawing of the command pattern (acceleration / deceleration component) in embodiment of this invention. 2 is a block diagram of a servo motor control device described in Patent Document 1. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing an internal configuration of an electric motor control apparatus 1 according to an embodiment of the present invention. The electric motor / load machine (the electric motor and its load machine are grouped into one block by the control apparatus 1. ) 7 is driven with a predetermined torque.
The motor control device 1 includes an input / output unit 2, a self-tuning unit 3, an automatic operation command generation unit 4, a position / speed adjustment unit 5, and a drive unit 6. The self-tuning unit 3 includes an interface unit 31 and an adjustment unit. It comprises a sequence unit 32, a control parameter operation unit 33, and an oscillation detection unit 34.

Next, the operation of this embodiment will be described together with the function of each part. Here, a case where the load machine is reciprocated by an electric motor will be described.
First, when a movement distance, a movement speed, and a start signal for performing these control operations are input as commands from the input / output unit 2, the command is transmitted to the interface unit. Further, the moving distance and moving speed are sent to the adjustment sequence unit 32 as set values.

The adjustment sequence unit 32 creates an acceleration / deceleration pattern for the electric motor based on the input movement distance and movement speed, and outputs the acceleration / deceleration pattern to the automatic operation command generation unit 4. The automatic operation command generation unit 4 creates a command pattern including a position command based on the acceleration / deceleration pattern, and outputs the command pattern to the position / speed adjustment unit 5.
The position / speed adjustment unit 5 uses the command pattern and the fed back state quantity (position / speed detection value) based on the position adjustment gain and the speed adjustment gain adjusted by the tuning operation described later. A speed adjustment calculation is performed, and a torque command based on the calculation result is generated and output to the drive unit 6. The drive unit 6 generates an applied voltage and current to the electric motor corresponding to the torque command by an internal power converter, and drives the electric motor / load machine 7 with a predetermined torque at a variable speed, thereby reciprocating the load machine. To control.

Next, the tuning operation in this embodiment will be described.
When a setting operation for self-tuning is instructed by a start signal sent from the input / output unit 2 to the interface unit 31, the adjustment sequence unit 32 sets parameters of an acceleration / deceleration pattern according to a tuning rule described later to an automatic operation command generation unit. 4, the automatic operation command generation unit 4 generates a position command for performing reciprocating motion and outputs a command pattern. As described above, the position / speed adjusting unit 5 performs the position / speed adjustment calculation based on the command pattern, and starts the reciprocating motion of the load machine by driving the electric motor at a variable speed via the drive unit 6. .

  At this time, in the control parameter operation unit 33 that has received a valid signal (a signal indicating that the self-tuning operation is valid) from the adjustment sequence unit 32, the position / speed adjustment unit 5 preset by the adjustment sequence unit 32. Operations such as gradually increasing control parameters such as position / velocity adjustment gain each time the reciprocating motion ends. The oscillation detection unit 34 to which the torque command from the position / speed adjustment unit 5 is input includes, for example, a high-pass filter, an absolute value circuit, a low-pass filter, a comparison circuit, and the like. Monitors and outputs the oscillation frequency (oscillation state) of the torque command.

  When the control parameter operation unit 33 detects the oscillation state of the torque command from the input oscillation frequency, the control parameter operation unit 33 operates the position / speed adjustment unit 5 so as to decrease the position / speed adjustment gain, and thereafter decreases the gain. The position / speed adjustment unit 5 is instructed to maintain the obtained gain. Note that if the gain is decreased and increased a plurality of times and retries are performed, reproducibility at the time of gain adjustment can be improved.

  Here, in the prior art shown in FIG. 4, the operation command pattern is fixed, and for example, the motor 110 is controlled to reciprocate at a constant speed based on the position command value. In contrast, in this embodiment, the control parameter of the tuning result is held in the memory, and the acceleration / deceleration component of the command pattern is changed according to the state of the load machine by the change designated in advance from the input / output unit 2. Repeat the tuning operation in the same way. This operation will be described below with reference to FIGS.

That is, as shown in FIG. 2, first, a tuning operation is performed under a command pattern (solid line pattern in FIG. 3) based on a set acceleration designated by the user from the input / output unit 2, and the position / speed at that time Control parameters such as adjustment gain are stored in the memory (step S1 in FIG. 2).
Next, a command pattern in which the set acceleration is increased by a change designated by the user from the input / output unit 2 according to the state of the load machine (in FIG. 3, a broken line pattern that is 1.2 times the set acceleration as an example) ) Is input to the position / speed adjustment unit 5 via the adjustment sequence unit 32 and the automatic operation command generation unit 4, and the tuning operation is executed based on the command pattern, and the control parameters at that time are stored in the memory. (Step S2 in FIG. 2). Further, similarly, a command pattern in which the set acceleration is reduced by the change designated by the user (in FIG. 3, a pattern of a one-dot chain line set to 0.8 times the set acceleration as an example) is used as the adjustment sequence unit 32 and the automatic operation command. While inputting to the position / speed adjusting unit 5 via the generating unit 4, a tuning operation is executed under the command pattern, and the control parameters at that time are stored in the memory (step S3 in FIG. 2).

  Finally, among the control parameters stored in the memory in each tuning operation, desired followability can be obtained with respect to the command pattern, and the control response is the lowest (that is, the gain is small and the control target varies). On the other hand, a control parameter that is robust to the control unit is selected as an optimal value (step S4 in FIG. 2), and the self-tuning operation of the gain in the position / speed adjustment unit 5 is completed.

  As described above, according to this embodiment, the control parameters such as the position adjustment gain and the speed adjustment gain are tuned to the optimum values based on the command pattern that is changed stepwise. Even when the acceleration / deceleration component changes or a load fluctuation occurs, the control loop does not become unstable and a highly robust control response can be obtained.

In the present embodiment, the command pattern (acceleration / deceleration pattern) that changes linearly as shown in FIG. 3 has been described. However, for example, a pattern that accelerates with a curve (such as an S-shape) may be used. An untargeted pattern may be used when decelerating.
In the present embodiment, the control parameter is described as a gain element. However, the controller includes a controller that locally operates the frequency characteristics of the closed loop, such as a notch filter, and the filter and gain control parameters can be tuned. Good.

1: Motor controller 2: Input / output unit 3: Self-tuning unit 31: Interface unit 32: Adjustment sequence unit 33: Control parameter operation unit 34: Oscillation detection unit 4: Automatic operation command generation unit 5: Position / speed adjustment unit 6 : Drive unit 7: Electric motor / load machine

Claims (3)

Command generation means for outputting a command pattern relating to the state quantity of the motor, adjustment means for controlling the feedback of the state quantity so as to follow the command pattern, and changing control parameters in the adjustment means based on the state quantity An electric motor control device that adjusts the control parameter to an optimum value by the parameter operating means while driving a load machine by the electric motor,
An electric motor control device that changes the command pattern according to a state of the load machine. In the motor control device according to claim 1,
An electric motor control device characterized in that an acceleration / deceleration component in the command pattern is changed stepwise. In the electric motor control device according to claim 1 or 2,
Among the control parameters tuned by changing the command pattern stepwise, a control parameter that achieves desired followability with respect to the command pattern and has the lowest control response is selected as an optimum value. An electric motor control device.

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