JPS6166580A - Controller for motor - Google Patents

Abstract

PURPOSE:To remove variation in a parameter and an influence due to disorder by presuming the parameter and disorder of a control system from a motor speed and the input of a drive force supplying amplifier, and deciding the input value of the amplifier to compensate it. CONSTITUTION:In a control system for controlling a motor 9 through a D/A converter 7 and a servo amplifier 8 by the output of an operating amount calculator 2, an input value of the amplifier 8 and a motor speed detected by a tachometer generator 10 within the prescribed period are input to a parameter/ disorder torque presuming unit 3. Then, the variation in the parameter of the control system and the variation in the disorder torque decided by the load of the motor and the output value of the amplifier 8 are presumed. The presumed value, the motor speed, the input value to the amplifier 8 and the target speed value 1 of the motor are input to the calculator 2 which calculates the input value to the amplifier 8 compensated for the variations in the parameter and the disorder torque.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a motor control device, and in particular, to a motor control device such as an electric robot, the moment of inertia and disturbance torque acting as a load on the motor change during rotation of the motor. The present invention relates to a motor control device suitable for various cases.

[Background of the invention]

Electric robots are basically controlled by controlling the speed of the motors. The speed control of this motor has the following characteristics.

1) The moment of inertia that acts as a load on the motor changes depending on the mass of the object held by the robot and the posture of the robot's arm, that is, the parameter of the controlled object changes.

2) Centrifugal force, Coriolis, and gravity act on the motor as a disturbance torque, and this disturbance torque changes during robot operation.

When controlling industrial robots, control is not performed that takes into account changes in the parameters of the controlled object and changes in disturbance torque, and as a result, trajectory accuracy is poor.

As a control method for dealing with changes in parameters of a controlled object and changes in disturbance torque, a method described in Proceedings of the Society of Instrument and Control Engineers, Vol. 17, No. 4, P467-P472 is known. This method basically calculates the amount corresponding to parameter changes and disturbance torque changes from the motor output value,
The speed command value to be input to the motor's servo amplifier is determined to compensate for this. However, the process of determining this command value requires adjustment of the variable gain,
This adjustment had to be made through trial and error.

Further, as a similar control method, the method described in the 26th Automatic Control Association Lecture Preprint P237-P238 is known. In this method, disturbance torque changes are calculated using equations of motion, parameter changes are basically estimated from motor output values, and a speed command value to be input to the motor's servo amplifier is determined to compensate for these changes. however,
The calculation is complex and requires high-speed calculation means.

[Purpose of the invention]

An object of the present invention is to estimate the parameters and disturbance torque of a controlled object and request the input to the servo amplifier to compensate for these, thereby reducing the influence of parameter changes and disturbance torque changes. The purpose is to provide a control device.

[Summary of the invention]

An example of a block diagram of a motor servo system can be expressed as shown in FIG. Here, u(t) is the input to the servo amplifier, y(t) is the rotational angular velocity of the motor, K1 is the gain of the servo amplifier, K2 is the product of the motor armature resistance and the torque constant, and K3 is the motor induction C is the voltage constant, C is the viscous resistance of the load, J is the moment of inertia of the load, Td is the disturbance torque, and S is the Laplace transform operator. Furthermore, the electrical time constant of the motor is usually two orders of magnitude smaller than the mechanical time constant, so it is omitted.

From this @9 figure, u (t) , rd(t) , y
(The relationship between tl is expressed as the following equation.

Here, U(s), to(s), Y(s)
are u (t) and rd(t), respectively.

This is a positive conversion of y (t). When performing computer control, it is more advantageous to use a discretized formula, so the left side of formula (1) is multiplied by a zero-order hold and transformed into a 2-transformed discretizer. T is the sampling interval and A-IT is (A
-x) means r. In FIG. 9, things that change during operation of the motor are J and Td(t).

Therefore, in equation (2), the terms corresponding to this parameter change and disturbance torque change are: ri+ , P2 , P
s and Td, and it is necessary to estimate these in order to achieve the above objective. -Here, if P5τd(a-IT) is rewritten as Td, it becomes the sum as shown in the following equation.

y(AT)=P+y(,'1-IT)+Pzu(A-t
T) + Td ・”(4) If the target value of the rotational angular velocity of the motor at time AT is yM(JT), the value u(A-IT) to be input to the servo amplifier at time (route t) is Pl , P2, and Td can be estimated, then by setting y(AT)=yM (at A) in equation (4), K can also be determined as shown in the following equation.

u (a-s T ) = (yu(at a)-P+y(
A -tT)-Td)/'P2 (51, that is, equation (4)
If Pl, P2, and Td can be estimated, the motor rotational angular velocity can be controlled arbitrarily.

Equation (4) generally becomes as follows when the controlled object is of a higher order than shown in Fig. 9, for example, when the transmission system of the motor rotational angular velocity includes a spring constant. .

y(AT)=p+y([]T)+pzy(A-TakumiT)
+・・・・・・+P9y(r7LT”) +P?L
++ u(A-1'r) + P? L+zu(A-2T
)+...+P90Ll(mouth T)+Td...
...(6) P1~pa+a', Td can be estimated as follows. First, every hour (A
-I, ) T-JIT sets these parameters P1 to P
If the rate of change of yL-+ML and Td is sufficiently short compared to the rate of change of Td, the parameter can be regarded as a constant value in this time interval, and the following equation holds true. However, L is preferably rust +1 or more.

Y (A) = A (AI P (J)
(7) Here, the subscript T to the right means transposition of a vector or matrix. By applying the least squares method to this equation (7), [P
The estimated value IP (43) of (J) is obtained. An example of this estimation method using the least squares method is described in "System Identification" pages 77 to 79&C published by the Society of Instrument and Control Engineers.In the estimation method of this document, the disturbance Although a term related to torque is not included, by following a procedure similar to this method, the remainder (J) can be found as shown in the following equation.

-(A) = CA"(J) A (A) )-'A"
(A) Y (A) . . . Here, the subscript −1 on the upper right side means an inverse matrix.

Therefore, if the target value of the rotational angular velocity of the motor at time AT is yx (JT), the value u (at A-I) to be input to the servo amplifier at time (A-+)T is given by equation (6). By replacing y (muT) in YMCA'T), I"1~PfL as this estimated value P+△~P?L+%, and Td with this estimated value Td, K also stops as shown in the following equation.

u(with A-I) = (yM(JT)-Pay(ruIT)
)---・--PrLy(r;0LT)-p? L+zu
By estimating (A-zT)- and the disturbance torque and using this estimated value to determine the input value to the servo amplifier from equation (4), the motor rotational angular velocity can be controlled arbitrarily.

However, it is necessary to consider the time required for calculation.

In other words, it is necessary to calculate the fields of Equation (1) and Equation (1) within a sampling interval of 1. In general, calculation to obtain the inverse matrix as in Equation (1) takes time. Therefore, Equation (12
) and formula (If the calculation of the river is not completed within sampling interval 1, it is necessary to simplify the calculation to obtain the inverse matrix of formula (la. Therefore, 1 matrix A(4) and A(A-1) Let the common element of the matrix B(4-1) be a matrix B(4-1).

Furthermore, one matrix F (A) and G (J) are defined as follows.

F(A): (A (AHA)) -1...
(I5) G (A)=CB (A) B (A) ]-1...
(16) A linear equation is obtained from equation (9), a4) to θG).

F (Al=G (A-1)+φ(A-1)φ(J
-1) ......(I7) Mu identification J P116~
When transformed with reference to P118, F (J) = G
CA-1) -〇 (A-1)φ(A-1)φ(A-1
) G (A-s)/j #(A-1)
−・−js)Δt(A−1)=1+φ(J!−
1) G ('-1)φC4-1)・・・・・・■)G
(A-x)=F (A-1)+F CA-1)φ(A
-L-1)φ(A-L-1)F(A-1)/Δf(A-
1) ......(21) Evening estimated value P o (
A) is obtained.

△ 1Po(A)= CB (4)B(A) '3 B
(MlYo (A) --@4To (A)=
Cy(JT) ,..., y(A-L+2T)
]...(24) Also, the following equation holds true.

1) y(rT, r) 94 or more formulas (12) and formulas (I9) to (2→) yield the following formula.

-y(through))/ΔfcA-1) ・・・・・・
(Foundation) △ Yo (JT): φ (A-1) Po (J!-t)
・・・・・・(2→y(A-LT) =φ(
A-L-1) P (A-t)...
・Figure Note that by further transforming the above equation, the following equation is obtained.

-(A)-〇(A-1)-G(A-1)φ(A-x)[
y(AT') -y(AT))/Δf(A-1)+("
I -G(A-t)φ(A-t)φ (Rule/Δ
y(A-t') ] F (A-1)φ(A-L-1
)x(y(A-LT) -y(τIT)]/Δf(A-
x) ......(31) Here,
■ is an identity matrix.

To summarize the above, the parameters of the controlled object and the disturbance torque are estimated from Equation 102) or the sequential form of Equation (2'71~(2) or Equation (31), and using these estimated values, Equation By determining the input value to the servo amplifier from (13), the motor rotational angular velocity can be controlled arbitrarily.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 to 8.

[Embodiment 1] The memory manager 5 (FIG. 1) receives the operation result u(4i-
Enter IT). Next, from memory 6, time (A-1)T
From (A-L-11)T, the speed of the motor 9 at each sampling time y(A-IT), -, y(A-t,
-7L+IT) l and time (A-2) from T (L
-tt+1) The input value to the servo amplifier 8 at each sampling time point u(A-27), -, u(A-t,
-%+IT,), and outputs the data retrieved from the memory 6 and the data input from the manipulated variable calculator 2 to the parameter/disturbance torque estimator 3. after that,
The unnecessary data y (A-L-?L+ t T ) and u (A-L-?L+ I T ) are erased from the memory 6, while new data u (A-IT) is written to the memory 6. Next, wait for a signal from timer 4, and when this signal (time A
After receiving T).

The speed y (AT) of the motor 9 is input via the A/D converter 11 and the tachometer 10. This data Y(,A
T) is output to the parameter/disturbance torque estimator 3. And data y (A-IT) from memory 6.

-v Y(A-?L+IT) and u(A-IT), -,
u(A-%+IT), outputs the data retrieved from the memory 6 and the data input from the A/D converter 11 to the manipulated variable calculator 2, and then sends new data y(JT) to the memory 6. Write. The following processing of the memory manager 5 is shown in the form of a flowchart in FIG.

The parameter/disturbance torque estimator 3 receives y(A-IT), which is an element of the matrix A(A), from the memory manager 5.

y (A-t, -?L+ t T ) and u (A-RyoT
) r ”' v After inputting the data of u (Rue L-% + lT), [”A (41A(
41) Calculate A (A). Next, vector Y(
λ) is received from the memory manager 5, and an estimated value P (J) of the parameter and disturbance torque is calculated according to formula fi2), and this value is sent to the manipulated variable calculator 2.
Output to. The processing of this parameter/disturbance torque estimator 3 is shown in the form of a flowchart in Figure $3.

The manipulated variable calculator 2 calculates the motor 9 at time (A+1)T.
After inputting the target value 1 of the rotational angular velocity of yhy (front T),
Input the estimated value P (41) of the parameter and disturbance torque from the parameter/disturbance torque estimator 3. Next, input the data y (k-IT) from the memory manager 5.

..., y (plan T) and u (A-IT), ...
, U ("declaration T") manually and according to formula (13) (however,
Replace A with a+t) Calculate the power value u(JT) input to the servo amplifier 8 at time AT, and convert this direct value to the D/A controller/
The calculated value is outputted to the °C Nervo amplifier 8 via the bar tuff, and the calculated value is further outputted to the memory manager 5. The processing of this manipulated variable calculator 2 is shown in the form of a flowchart in FIG.

The timer 4 outputs a signal to the memory manager 5 at every time interval T. According to this embodiment, parameters and disturbance torque can be estimated using a simpler algorithm than in other embodiments.

[Embodiment 2] The memory manager 5 inputs the calculation result u(A-IT') from the manipulated variable calculator 2. Next, from the memory 6, y(A-IT), -,' y(A-L-zT) and U(A-2T).

. After that, data Y (A-[,-n
T) and u(A-L-zT) from memory 6,
Write new data u(A-IT) to memory 6.

Next, it waits for a signal from the timer 4, and after receiving this signal, the speed y (AT) of the motor 9 is inputted via the A/D converter 11 and tachometer 10.

This data Y (JT) is output to the parameter/disturbance torque estimator 3, and then data y (A-tT) is output from the memory 6.
, -, Y (A-yc+tT) and U (mouth T), -.

Take out u (A-?L+ I T ). The data retrieved from the memory 6 and the data input to the A/D converter 1 are output to the manipulated variable calculator 2, and new data y (JT) is written to the memory 6. The above processing of the memory manager 5 is shown in the form of a flowchart in FIG.

Parameter disturbance torque estimator 3 is memo + 7 manager 5
From matrix A (A)), element y (A-1) of matrix A (A-1)
ears T).

..., y (A-I, -?LT) and u (at a-t)
, -, after inputting u(a-L-?LT), G(A-1) is calculated using equation 18) K: Therefore. Next, F (41 is expressed as (+
7), the inverse matrix F (
A), and further calculate B (A-t) Yo(A-1
) is calculated according to the formula). After this vector Y(A)
The element y(AT') of is input from the memory manager 5, and A
fA) Y(J) is calculated according to equation (21), and an estimated value P(4) of the parameter and disturbance torque is obtained from these calculation results and equation (+2), and this estimated value is applied to the manipulated variable calculator 2.
Output to. The processing of this parameter-dependent disturbance torque estimator 3 is shown in the form of a flowchart in FIG. The functions of the manipulated variable calculator 2 and the timer 4 are the same as in the first embodiment. According to this embodiment, A in estimating parameters and disturbance torque
(')A(Jl can be calculated faster than in the first embodiment.

[Third Embodiment] The functions of the memory manager 5, operation amount calculator 2, and timer 40 are the same as in the second embodiment. Parameters
The disturbance torque estimator 3 receives yσ from the memory manager 5 (T),
..., y (A-L-9T) and u (at A-t), -
, u(A-L-7LT), G(A-1) is expressed as (
2η, (c), Fl) is calculated according to the formula (+91,
(Calculated according to 21J. On the other hand, after calculating y (A-LT) according to formula (34), the estimated △ value Pa (A-1) of the parameters and disturbance torque is calculated according to formula 0, and based on this result, △ Calculate ys(AT) according to formula (21). Next, 7(
AT) is input from the memory manager 5, and the estimated value PfA) of the parameter and disturbance torque is calculated according to formula +27).

This estimated value ' is output to the manipulated variable calculator 2. The processing of this parameter/disturbance torque estimator 3 is shown in the form of a flowchart in FIG. According to this embodiment, since the calculation of the inverse matrix is not included in the estimation of parameters and disturbance torque, this estimation can be performed faster than in embodiments 1 and 2.

[Embodiment 4] The functions of the memory manager 5, manipulated variable calculator 2, and timer 4 are the same as in the second embodiment. Parameters
The disturbance torque estimator 3 receives y(A-IT
), ..., y(A-L-?LT) and u(A-tT
), -・, after inputting u(A-L-aT), G(A-1
) is calculated according to formula (21), and F (, G
) is calculated according to equations (19) and (20).

On the other hand, y(A-LT) and y(AT) are calculated according to formula (3C1), y(JT) is input from the memory manager 5, and the estimated value ΔP (A) of the parameter and disturbance torque is calculated according to formula (3C1). ] I K is calculated accordingly.Then, this estimated value is output to the manipulated variable calculator 2.The processing of this parameter/disturbance torque estimator 3 is shown in the form of a flowchart in FIG. 8.According to this embodiment, the parameter Since the calculation of the inverse matrix is not included in the estimation of the disturbance torque, this estimation can be performed faster than in the first and second embodiments.

〔Effect of the invention〕

According to the present invention, the parameters and disturbance torque of the controlled object can be estimated, and the estimated values are used to create values input to the servo amplifier of the motor. Since the servo system is configured to compensate for this, it has the effect of being less susceptible to changes in the parameters of the controlled object and disturbance torque.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a servo system according to the invention, FIGS. 2 to 8 are diagrams showing embodiments of the invention, and FIG. 9 is a block diagram of a motor and a servo amplifier. 1... Target value of motor rotational speed 2... Manipulated amount calculator 3... Parameter/disturbance torque estimator 4... Timer, 5... Memory manager 6... Memory,
7...D/A converter 8...Servo amplifier, 9...Motor 10...Tachometer 1, 11...
・A/D converter. r+Representative Patent Attorney Akira Takahashi
Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 7 Figure 3

Claims (1)

[Scope of Claims] 1. A motor control system comprising a motor, an amplifier that supplies the driving force of the motor, and a control device that provides an input value of the amplifier, wherein the control device controls the motor, the load of the motor, and the control device that provides the input value of the amplifier. an estimator that estimates the parameters of the control system determined by the output value of the amplifier and the disturbance torque applied to the motor from the speed of the motor within a predetermined time and the input value to the amplifier; an arithmetic unit that calculates an input value to the amplifier from a value, a speed of the motor within the predetermined time, an input value to the amplifier, and a target speed of the motor. .