JPH01238489A - Force addition type multiplex motor driven servo actuator - Google Patents

Abstract

PURPOSE:To detect the trouble of a system with high reliability by obtaining a current signal with a function simulator from a phase command, and comparing it with a current command signal to detect the trouble. CONSTITUTION:Two servo motors 1a, 1b are mechanically coupled at their rotors to the same output shaft 2 to add their torques to drive a load at the shaft 2. First stage self-diagnosing circuits 7a, 7b detect the propriety of the value of a current command CCa or CCb of driving systems A, B, and input a position command signal PC and the signal CCa or CCb. The circuits 7a, 7b obtain a current value by a function simulator from the signal PC, compare it with the signal CCa, CCb, and output a current command trouble signal FIa or FIb.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Use This invention is for driving industrial equipment, devices, etc. that require high rotation performance, such as control surfaces of aircraft and other flying objects, arms of industrial robots, etc. The present invention relates to an electric servo actuator device equipped with multiple drive systems.

Conventional technology In servo actuator devices for driving devices that require high reliability, such as aircraft control surfaces, it has been common practice to use multiple systems to ensure the necessary operational reliability. In particular, in multiple actuator devices using servo motors, the simplest and most reliable method is a force addition type multiple electric actuator device in which the rotor of each servo motor is directly connected mechanically and each servo motor is controlled by a separate control circuit. This method has high transferability.

However, in this case, due to the simple force addition method, if the total generated force required for the actuator is not evenly distributed among multiple servo motors, the differences in characteristics that exist in each part of each system will ultimately affect each servo motor. This causes a difference in the generated torque. Therefore, even when the actuated object is held in a fixed position, that is, even when the amount of work to the actuated object is zero, a phenomenon in which each servo motor generates torque in the opposite direction and opposes each other (force-fire) occurs. However, not only will the output of the entire device decrease accordingly, and the hysteresis phenomenon will appear in the static characteristics due to the generation of a dead zone, but also the operating characteristics will deteriorate, and due to the force fight, each servo motor and power amplifier will be made useless. Current flows and increases heat generation.If the output of the servo motor is limited to avoid this, it is not possible to make the servo motor smaller and lighter.Therefore, a means such as an equalizer is required to equalize the torque generated by the servo motor. However, the conventional equalizer used for multiple electric motors requires a motor torque detector, cannot directly connect the motor rotor mechanically, and has a complicated structure.

In addition, in order to obtain high reliability in multiple systems, it is necessary to be able to detect failures in each system and to be able to isolate the failed part or system without adversely affecting normal parts or overall operation. Comparing the position command signal and position feedback signal for each system, which is a conventional self-diagnosis method, cannot be used for failure detection because the force addition method cannot determine which system is at fault. Conventionally, there is no technology that can self-diagnose failures in everything from power amplifiers to motors without using them.

In addition, in the conventional failure detection method by comparing motor currents between multiple motors, even if a failure is detected when two motors are operating, it is not possible to determine which system is at fault. There are limits to how much credibility can be improved through multiplexing.

As described above, there is a big problem in reducing the size and weight of a multiple electric servo actuator to obtain high rotation performance.

Furthermore, when using a pulse width modulation type servo amplifier, the servo motor's t-flow liquid type is a harmonic modulation waveform,
In this state, self-diagnosis cannot be performed by comparing with the current I command signal.

Furthermore, in pulse width modulation type C brushless servo motors that have recently been used to obtain small and large outputs, the direction of the generated torque cannot be determined even if the motor current is detected, so the motor current signal cannot be determined. cannot be used in conventional equalizers or for fault detection.

Problems to be Solved by the Invention The problem to be solved by the present invention is to solve the various problems in the prior art described above.Therefore, an object of the present invention is to provide a force addition type multiple electric servo actuator device that solves the above problems. There is something to do.

Means for Solving the Problems To achieve the above object, the specified invention provides an electric servo motor and a position control system that compares a common position command signal with a negative feedback signal from a position sensor coupled to an output bearing of the electric servo motor. A plurality of drive systems each having a compensation circuit and a current command selection circuit that supplies the output of the position compensation circuit to a power amplifier for driving the electric servo motor are provided, and the rotors of each electric servo motor are mechanically coupled to each other, and the A first stage self-diagnosis circuit is installed in the drive system of the drive system to output a discrimination signal corresponding to the magnitude of the absolute value of the difference between the position command signal and the output of the position compensation circuit of the drive system, and the current command of the entire drive system is The selection circuit selects the output of the position compensation circuit of the drive system having the smaller discrimination signal among all the discrimination signals and supplies it to all the power amplifiers, and supplies it to the input of the power amplifier and the electric servo motor to another required drive system. The electric servo motor is characterized in that the electric servo motor is opened when the difference between the electric current and the electric current exceeds a predetermined value.

Further, the second invention is a first stage self-diagnosis circuit in the specified invention, which outputs a position command signal of a drive system through a high-pass filter or a band-pass filter, and a signal obtained by multiplying the position command signal by a proportional gain, or the signal. It has a configuration that outputs a discrimination signal corresponding to the magnitude of the absolute value of the difference between the sum of the output of the current command signal or the output of the current command signal passed through the low-pass filter, and the output of the current command signal or the output of the current command signal passed through the low-pass filter.

Further, the third invention provides that when a DC brushless motor is used as the electric servo motor in the specified invention, the second stage self-diagnosis circuit detects the absolute value of the current command signal and the absolute value of the DCC brushless morph each phase current signal. The DCC brushless morph is configured to open when the difference between the sum or the difference between the absolute value of the current command signal and the value obtained by passing the sum through a low-pass filter or a band-pass filter, respectively, exceeds a predetermined value.

Function: When multiplexing a drive system, the present invention constructs a servo loop from a position command signal input terminal to an electric servo motor to a position sensor connected to the electric servo motor in two stages, one before and one after the input terminal of the electric servo motor drive power amplifier. In the first stage including the position command signal input terminal, a first stage self-diagnosis circuit is installed in the required drive system to prevent force fights between the electric servo motors of each drive system due to malfunction of the servo loop. The existence and degree of the malfunction in the drive system is determined respectively, and all of these determination signals are sent to the current command selection circuit of each drive system, where the current command signal for the drive system with the least malfunction is selected. let Since the power amplifier of each drive system drives the electric servo motor of each drive system based on this selected common t-flow command signal, the torque of each electric servo motor becomes equal, and force fight is eliminated. In this case, the device can operate if a current command signal for at least one drive system is obtained.

In addition, at the stage downstream from the input end of the power amplifier, a second-stage self-diagnosis circuit provided for each drive system monitors the electric servo motor's actual current signal to ensure that it does not exceed the current command signal, providing overcurrent protection. .

The second invention uses a high-pass filter or a low-pass filter to prevent the first stage self-diagnosis circuit in the specified invention from malfunctioning due to harmonic electrical noise generated in the drive system or noise caused by mechanical vibration. Since it is common for a servo motor to be subjected to a load proportional to its output displacement, the position detection signal is automatically corrected using a proportional gain to accommodate this load.

Furthermore, in the third invention, when a DC brushless motor is used as the electric servo motor, self-diagnosis is effectively performed by making each phase current of the servo motor equally relative to the current command signal. , the influence of harmonics included in the current of a DC brushless motor is removed to make self-diagnosis accurate.

Embodiment FIGS. 1 to 3 are block circuit diagrams of an embodiment of the present invention having dual drive systems A and B.

The rotors of the two servo motors la and lb are mechanically coupled to the same output shaft 2, and torque is added to the output shaft 2.
drives the load. Each servo motor is attached to the output shaft 2.
Independent position sensors 3a, 3b and speed sensors 4a, 4b corresponding to the sensors a and lb are installed, and these sensors receive position detection signals PFa, PFb and speed detection signal V, respectively.
Fa and VFb are connected to the position compensation circuits 5a of drive systems A and B, respectively.
.

5b and speed compensation circuits 6a and 6b.

Position compensation circuit 5a. 5b multiplies the difference between the position command signal PC and the position detection signal PFa or PFb by a predetermined gain, and outputs speed command signals VCa and cb, respectively. Further, the speed compensation circuits 6a and 6b each receive a speed command signal VCa.
and the speed detection signal ■Fa and the difference between the speed command signal vcb and the speed detection signal VFb are multiplied by a predetermined gain to output current command signals CCa and CCb, respectively.

The first stage self-diagnosis circuits 7a and 7b each have a drive system A,
As shown in FIG.
Even if the 0 position command signal PC that inputs C and the current command signal CCa or CCb is a constant target signal, the servo motors la and lb go through a transient state and reach a steady state, so the current command signals CCa and CCb is also a signal corresponding to this, so for comparison, the signal PC is passed through a high-pass filter or a band-pass filter 8 which simulates the transient state and also prevents malfunction due to noise.
and servo motor la to signal PC.

1b, a signal multiplied by a proportional gain ring 9 representing the steady state load current, or a signal i obtained by passing this through a low-pass filter 10
A comparator 12 detects the difference between the signal i and the signal CCa or CCb passed through a low-pass filter 11 to prevent a phase shift, and the difference is detected by the absolute value circuit. A comparison circuit 14 compares the signal C passed through 13 with a predetermined reference signal C0. The comparison circuit 14 has C>C
If it is 0, the current command failure signal Fla or Flb is output, which is 0 if the binary signal LC≦C0.

When the load is such that the current of the servo motors la and lb is generally proportional to the output displacement, such as in the case of an aircraft, the proportional gain 9 becomes a constant, but for other loads, an appropriate function simulation circuit is used.

Current 1 command signal selection circuits 15a and 15b are drive systems A and B.
Current command signal C common to power amplifiers 16a and 16b
For example, as shown in FIG. 3, this is a circuit for supplying current command signal CCa and CCb through an AND gate 17 to which current command failure signals Fla and Flb are input, a changeover switch 18 for current command signals CCa and CCb, and an AND gate 18 to which current command failure signals Fla and Flb are input. It consists of a changeover switch 19 that switches between the output of the gate 17 and the output of the gate 17 . When the signal Fla is 0, the switching switch 18 is switched to the signal CCa side as shown in the figure, and when the signal Fla is 1, it is switched to the signal CCb side. In addition, when the current command failure signal Fla and F l b are both 1 and the AND gate output is 1, the switching switch 19 switches to the ground side and the signal CC becomes O.
However, when the AND gate output is O, it is in the state shown in the figure and outputs the signal CCa or CCb. This output switching state is shown in the table below.

Fla Fib AND gate output CC That is, if neither of the self-diagnosis circuits 7a and 7b detects a failure, the power amplifiers 16a and 16b receive the same signal CCa.
is input to equalize the generated torque of the servo motors la and lb. If either of the self-diagnosis circuits 7a and 7b detects a failure, it cuts off the failure signal CCa or CCb to ensure that there is no failure. The side signal CCa or CCb is simultaneously supplied to both power amplifiers 16a and 16b to control the generated torque of the servo motors la and lb. Therefore, Force Fight cannot be surpassed. In addition, the self-diagnosis circuit 7a
, 7b are both failed, the power amplifiers 16a, 1
The input 6b becomes 0, and the servo motors la and lb stop.

Power amplifiers 16a and 16b receive input signal CCa or CC
Torque corresponding to b is applied to servo motor la.

This is a normal power amplifier that outputs a controlled current so as to be generated at 1b.

The second stage self-diagnosis circuits 20a and 2Ql) both use the output signal CC of the current command selection circuit 15a or 15b and the current sensor 2 of the servo motor la or 1b in the drive system.
Compare the motor current signal CFa or CFb taken out from 1a or 21b, and when the absolute value of each difference exceeds a preset reference value, open the contact 22a or 22b of the tM1 switch of the own system. , or power amplifier 16a,
By operating the logic circuit in 16b, the servo motors 1a,
1b is opened.

In addition to the above embodiments, the first stage self-diagnosis circuits 7a and 7b may be conventional self-diagnosis circuits that compare inputs and outputs of various parts of the circuit.

Further, when the amplifiers 16a and 16b perform pulse width modulation type amplification, the second stage self-diagnosis circuits 20a and 20b receive the servo motor current signal CFa or CFb from the current sensors 21a and 21b, as shown in FIG. is passed through the low-pass filter 23 and the current command signal CCa or C
Cb or the output obtained by passing these through the low-pass filter 24, and the comparison result is passed through the absolute value circuit 32. From the signal FII, which is the comparison result between the signal C' and the reference value CI, the signal F is generated.
The presence or absence of a failure is determined in the same manner as in 1.

The second self-diagnosis circuit 25 when DC brushless motors are used as the servo motors 1a and 1b is shown in FIG. The values passed through the absolute value circuit 27 are compared through the respective low-pass or band-pass filters 28 and 29, and the comparison results are converted into the absolute value 11 obtained through the absolute value circuit 30.
and standard value ■. A comparison circuit 31 determines the magnitude of the difference between the two and performs self-diagnosis. Furthermore, it is preferable to add a circuit indicated by a broken line that determines that the motor has failed if the sum of the current signals of each phase does not become O.

The above is an example of A, 82-layer system, but it is also possible to implement a triple-layer system or more.For example, in the case of a triple-layer system, three first-stage self-diagnosis circuits belonging to each prefecture The current command signals CCa, CCb, and CCc may be selected according to the circuit shown in FIG. 6 using the binary signals of the current command failure signals Fla, Feb, and Flc.

That is, with the same logical configuration as in FIG.
When Fa is 0, all CCa, and when IFa is 1, I
When Fb is O, CCb is selected and output, and when IFa and IFb are both 1 and IFc is 0, CCC is selected and output.
If a, IFb, and IFc are all 1, the output will be O.

It is easy to understand that it can be implemented in the same manner in the case of a quadruple system or more.

Note that the present invention can be practiced even when each drive system does not have the speed compensation circuit 6a, etc., the speed sensor 4a, etc., and a part of the plurality of drive systems may have the first stage self-diagnosis circuit 7a, etc. It is possible to operate even when the second stage self-diagnosis circuit 20a and the like are missing.

Effects of the Invention By having the above configuration, the present invention can produce the following special effects.

(1) Since the same current command signal is always input to the power amplifier of each drive system, each servo motor generates the same torque and no force fight occurs. There is no hysteresis phenomenon that appears in static characteristics due to the generation of a dead zone, and the operating characteristics are good.There is no heat generation in the servo motor due to force fight, and there is no need for an equalizer, making the entire device smaller and lighter.

(2) Since the first stage self-diagnosis circuit determines failure based only on the signals of the relevant drive system, there is no mutual influence with other drive systems, and this determination result controls all drive systems, so the position For failures between the sensor and the position compensation circuit,
l If the drive system is normal, the entire system can be operated and safety is high.

(3) Failures between the power amplifier and the electric servo motor are detected for each drive system by the second-stage self-diagnosis circuit, and the servo motor of the failed drive system is isolated, allowing the entire drive system to be repaired without affecting other drive systems. It can continue to operate.

(4) Even if multiple drive systems out of all drive systems fail simultaneously, one system from the position sensor to the position compensation circuit and one system from the power amplifier to the servo motor are separate drive systems. If it is normal, the entire operation can continue.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is an overall block circuit diagram of the two-acting system, Fig. 2 is a block circuit diagram of the first stage self-diagnosis circuit, and Fig. 3 is a logic circuit of the current command selection circuit. figure,
Figure 4 is a block circuit diagram of the second stage self-diagnosis circuit when the pulse width modulation method is used to drive the electric servo motor.
The figure is a block circuit diagram of the second stage self-diagnosis circuit when an electric servo and a DC brushless motor are used as the motor, and FIG. 6 is a diagram similar to FIG. 3 in the case of a triple system. la, lb...Electric servo motor 2...Output shafts 3a, 3b...Position sensors 5a, 5b...Position compensation circuits 7a, 7b...1st stage self-diagnosis circuit 8...High-pass filter Or band pass filter 9.
...Proportional gain ring to, 11...Low pass filter 29...Low pass filter or band pass filter A
, B... Drive system Fig. 3 M4

Claims (3)

[Claims] (1) An electric servo motor, a position compensation circuit that compares a common position command signal and a negative feedback signal from a position sensor coupled to the output shaft of the electric servo motor, and a position compensation circuit that uses the output of the position compensation circuit to drive the electric servo motor. The rotor of each electric servo motor is mechanically coupled to each other, and a position command signal and position compensation of the drive system are provided to the required drive system. A first-stage self-diagnosis circuit is provided that outputs a discrimination signal corresponding to the magnitude of the absolute value of the difference with the output of the circuit, and a current command selection circuit for the entire drive system outputs a discrimination signal that is smaller among all the discrimination signals. Selects the output of the position compensation circuit of the drive system that has the drive system and supplies it to all power amplifiers, and supplies the output of the position compensation circuit of the drive system with the electric servo A force addition type multiplex electric servo actuator device characterized by being provided with a second stage self-diagnosis circuit that opens a motor. (2) The first stage self-diagnosis circuit outputs an output obtained by passing the position command signal of the drive system through a high-pass filter or a band-pass filter, and a signal obtained by multiplying the position command signal by a proportional gain, or an output obtained by passing the signal through a low-pass filter. Claim 1: outputting a discrimination signal corresponding to the magnitude of the absolute value of the difference between the added value and the current command signal or the output of the current command signal passed through a low-pass filter.
The described force addition type multiple electric servo actuator device. (3) When a DC brushless motor is used as the electric servo motor, the second stage self-diagnosis circuit detects the difference between the absolute value of the current command signal and the sum of the absolute values of the current signals of each phase of the DC brushless motor, or the current The force addition type multiple electric servo actuator device according to claim 1, wherein the DC brushless motor is opened when a difference between the absolute value of the command signal and the sum passed through a low-pass filter or a band-pass filter, respectively, exceeds a predetermined value. .