JPH117303A - Driving controller for servo system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a stable servo system by decreasing the resonance peak of a rotary body and a structure controlled by this rotary body without providing any conventional notch filter. SOLUTION: A motor acceleration signal 15 detected by an acceleration detector in a block 18 is multiplied by a transfer function G(S) of a block 13, and this multiplied value is feedback to a current command signal from a temperature compensator 17. Thus, no inertia of a motor in the block 18 is changed within the response band of a servo system, and the equivalent inertia of the motor is controlled so as to be increased outside the response band of the servo system including a resonance point between the motor and a structure model 7. Thus, the resonance peak of the motor and the structure can be decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive control device for a servo system which aims at causing a rotation speed of a rotating body such as a motor to follow a command value by a minor loop.

[0002]

2. Description of the Related Art FIG. 8 is a block diagram of a conventional servo drive control device. In FIG. 8, 3 is a proportional gain K
_V indicates a block, 4 indicates a filter, 5 indicates a torque constant T _M , and 6 indicates a motor as a rotating body having inertia (inertia) J _M (for example, a direct drive motor can be considered). block, block 8 indicating the integrator for calculating the rotational position of the motor, 9 blocks indicating rigidity K _L between the motor and the load, block showing the load 10, 11 is an integrator which calculates the position of the load It is a block showing. 2 is proportional gain K
_V (block 3) and velocity compensator with filter (block 4). Reference numeral 12 denotes a motor speed signal indicating the rotation speed of the motor detected by a speed detector serving as speed calculation means attached near the motor indicated by the block 6. It is assumed that the block 6 includes a motor and a speed detector. 1 is a proportional gain K _V (block 3), a filter (block 4), a torque constant T _M (block 5), a motor (block 6), and a motor speed signal 1.
2 illustrates a configured speed minor loop including: 7
Are the motor and speed detector (block 6), the integrator (block 8), the rigidity K _L (block 9), and the load (block 1).
0) is shown. Also, 1
a, 7a and 7b are subtractors. In FIG. 6, the current loop is omitted for simplification. In FIG. 6, the equation of motion of the structure model 7 to be controlled is represented in the form of a transfer function.

Next, the operation will be described. In the speed minor loop 1, a speed command signal which is an input value of the speed minor loop 1 and a motor speed signal 12 detected by a speed detector included in the block 6 are subtracted by a subtracter 1a.
And the error is calculated and given to the speed compensator 2. The error given to the speed compensator 2 is P-compensated (compensated for proportionally) by a proportional gain K _V (block 3) and compensated for a resonance peak by a filter (block 4). Constant T
_M (block 5) is multiplied to obtain an input torque signal of the structure model 7. When a speed detector is not provided, a configuration may be adopted in which a position detection signal from an encoder attached to the motor is differentiated by a computer or the like to calculate the rotation speed of the motor.

[0004]

Since the conventional servo drive control device is constructed as described above, for example, control of a structure using a direct drive motor without a speed reducer as a controlled object to be driven. The motor inertia J
_{If M} is not sufficiently large compared to the inertia J _{L of the} structure, the resonance point and the anti-resonance point are separated, the resonance peak becomes high, and it becomes difficult to stabilize the control system due to the phase delay due to the dead time. In addition, it is necessary to provide a filter (mainly a notch filter) in the speed compensator so as to match the frequency of the resonance peak of the structure model to reduce the peak gain. Therefore, a notch filter that approximates the inverse characteristic of the resonance peak must be optimally set, and it is necessary to estimate or measure the resonance frequency in order to determine the characteristic of the notch filter. In some cases, the position of the filter changes depending on the posture, and when it is desired to increase the response band of the servo system, there is a problem that it is difficult to optimally set the filter.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and includes a notch filter or the like for lowering a resonance peak between a rotating body such as a motor and a structure controlled by the rotating body. There is no need to provide, and the resonance point and anti-resonance point of the rotating body and the structure are brought close to each other without changing the characteristics within the response band of the servo system, resulting in lowering the resonance peak and obtaining a stable servo system It is an object of the present invention to provide a servo-system drive control device that can perform the above-described operations.

[0006]

According to a first aspect of the present invention, the inertia of the rotating body is not changed within the response band of the servo system based on the acceleration of the rotating body, and the rotating body and the rotating body are controlled by the rotating body. Outside the response band of the servo system including the resonance point with the structure, the control is performed so as to increase the equivalent inertia of the rotating body.

According to a second aspect of the present invention, there is provided a speed compensating means (speed compensator 17) for compensating the rotational speed of the rotating body (the motor in the block 18) by performing P compensation by a proportional gain, and a rotating speed of the rotating body. A speed calculating means (integrator of block 14) for calculating and feeding back to the speed compensating means;
An acceleration calculating means (acceleration detector in block 18) for calculating the acceleration of the rotating body; and an inertia of the rotating body in a response band of the servo system based on the acceleration calculated by the acceleration calculating means. Outside the response band of the servo system including the resonance point between the rotating body and a structure controlled by the rotating body (structure model 7), the inertia for controlling to increase the equivalent inertia of the rotating body. Control means (the transfer function of the block 13).

According to a third aspect of the present invention, there is provided a speed compensating means (speed compensator 17) for compensating the rotational speed of the rotating body (the motor in the block 6) by performing P compensation by a proportional gain, and a rotating speed of the rotating body. Speed calculating means (speed detector in block 6) for calculating the speed and feeding it back to the speed compensating means
The acceleration is obtained from the rotation speed calculated by the speed calculation means, and based on the acceleration, the inertia of the rotation body is not changed within the response band of the servo system, and the rotation is controlled by the rotation body and the rotation body. Outside the response band of the servo system including the resonance point with the structure (structure model 7), the inertia control means (the differential element of the block 16 and the transfer function of the transfer function) for controlling so as to increase the equivalent inertia of the rotating body. (Product).

According to a fourth aspect of the present invention, as the inertial control means in the second aspect, the acceleration calculated by the acceleration calculating means (the acceleration detector in the block 18) is inputted, and a curve representing the frequency characteristic of the servo system is provided. And a transfer function calculated on the basis of the frequency of the break point.

According to a fifth aspect of the present invention, as the inertial control means in the third aspect, the acceleration is obtained by inputting the rotation speed calculated by the speed calculating means (the speed detector in the block 6). It is characterized by including a transfer function calculated based on the frequency at the break point of the curve showing the frequency characteristic.

According to a sixth aspect, in the fourth or fifth aspect, a high-pass filter which responds at a certain frequency or more outside a response band of a servo system is used as a component for generating a transfer function. It is a feature.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a drive control device for a servo system according to the first embodiment. In FIG.
3 is a block showing the proportional gain K _V , 17 is a block 3
A speed compensator as speed compensating means having a gain K _V of 5, a block indicating a torque constant T _M, and an inertia J _M
Is a block showing a motor (a direct drive motor can be considered as an example, but the present invention is not limited to this) as a driven control object (rotating body) having It is assumed that the block 18 includes the motor and an acceleration detector as acceleration calculation means. 14 is a block showing an integrator as a speed calculating means for calculating the rotation speed of the motor and feeding it back to the speed compensator 2, 8 is a block showing an integrator for calculating the rotation position of the motor, and 9 is a block between the motor and the load. A block indicating the rigidity K _L of the block, 10 a block indicating the load of the inertia J _L ,
11 is a block showing an integrator for calculating the position of the load, 1
2 is a motor speed signal Y (S).

Reference numeral 13 denotes a motor and a structure driven by the motor which do not change the inertia of the motor within a response band of the servo system based on the motor acceleration signal 15 from the acceleration detector included in the block 18. A transfer function G as an inertia control means for controlling so as to increase the equivalent inertia of the motor outside the response band of the servo system including the resonance point.
It is a block showing (S). 1a is a subtractor for calculating a difference between a speed command signal U (S) as an input value and a motor speed signal 12, 16 is an output of a speed compensator 17 and a block 13
A subtractor for calculating the difference between the output of the block 15 and the output of the block 9; 7b
Is a subtractor for calculating the difference between the output of the block 8 and the output of the block 11.

1 is a subtractor 1a, 1b, 7a, a speed compensator 17, a torque constant T _M (block 5), a motor and acceleration detector (block 18), an integrator (block 14), and a transfer function (block 13). And a speed minor loop comprising: The minor loop 1 of this speed feeds back the signal from the block 13 to the current command value. 7 is a motor and acceleration detector (block 18)
An integrator (block 14) and an integrator (block 8) subtractor 7a, 7b and rigidity K _L (block 9) and the structure model consisting comprises loading a (block 10) and an integrator (block 11) Is shown.

Next, the operation will be described. In the speed minor loop 1, the speed command signal U (S), which is the input value of the speed minor loop 1, is compared with the motor speed signal 12 from the integrator (block 14) by the subtracter 1a, and the error is calculated. The result is supplied to the speed compensator 17. The error given to the speed compensator 2 is P-compensated by the proportional gain Kv (block 3), and becomes a current command signal. This current command signal is included in a block 18, a signal obtained by multiplying a motor acceleration signal 15 detected by an acceleration detector attached near the motor by a transfer function G (S) of the block 13 and a subtractor 1 b. Are compared,
The error is calculated, and the error is then added to the torque constant TM
(Block 5) to obtain an input torque signal of the structure model 7.

As described above, in the first embodiment, a motor acceleration is detected by the acceleration detector attached near the motor, and a signal obtained by multiplying the acceleration by the transfer function G (S) is fed back to the current command signal. It has a minor loop 1 with a speed that is high. The transfer function G (S) is for changing the equivalent inertia of the motor without changing the inertia of the motor in order to avoid resonance between the motor of the servo control system and a structure controlled by this motor. For example, this is realized by using a high-pass filter that has a small response within the response band of the servo system and responds at a certain frequency W0 or higher outside the response band (higher than the response band) of the servo system. By feeding back the signal output from the transfer function G (S) to the current command signal, it is possible to increase the equivalent inertia of the motor on the high frequency side of the frequency W0 or higher. Becomes closer to the anti-resonance point, and as a result, the resonance peak is lowered, and a stable servo system can be obtained.

For example, a fixed frequency (a break point described later)
Transfer function G (S) when using a high-pass filter that responds above W0 (100 rad / sec)
Is

[0018]

(Equation 1)

## EQU1 ## Further, the resonance frequency W1 of the control object
And the frequency W0 and the frequency (design value) W2 in the response band of the servo system are W1>W0> W2. That is,

[0020]

(Equation 2)

## EQU1 ## However, the transfer function G (S) is not limited to the first-order high-pass, but may be any as long as it is higher than the response band of the servo system and has a characteristic of increasing equivalent inertia.

FIG. 2 shows the transfer function G shown in the above equation (1).
It is a Bode diagram which shows the frequency characteristic of (S). In FIG. 2, reference numeral 21 denotes a gain curve. In this case, the slope is +20.
9 shows the transfer function G (S) of the equation (1) of dB / dec. 2
2 indicates a phase curve corresponding to the transfer function G (S).

FIG. 3 is a Bode diagram showing frequency characteristics of the servo system in which the transfer function G (S) and the motor acceleration signal in FIG. 1 have been cut. In FIG. 3, reference numeral 31 denotes a gain curve. The gain curve 31 has a simple inertia J since a spring included in the structure model can be regarded as rigid in a low frequency range.
The inclusive characteristic proportional gain compensation systems with _M + J _L.
The gain at a slope of -20 dB / dec in the gain curve 31 is 1 rad / sec.

[0024]

(Equation 3)

## EQU1 ## Also, the point 31a of the gain curve 31
Indicates a resonance point, and the resonance point 31a is

[0026]

(Equation 4)

## EQU1 ## The anti-resonance point 31b is

[0028]

(Equation 5)

## EQU1 ## The gain curve 31, the spring constant in the high frequency range, so can be regarded as zero, the inclusive characteristic proportional gain compensation systems with simple inertia J _M. The gain at a slope of −20 dB / dec in the gain curve 31 in the high frequency range is 1 rad / sec.

[0030]

(Equation 6)

## EQU1 ## In FIG. 3, reference numeral 32 denotes a phase curve corresponding to the gain curve 31.

FIG. 4 is a block diagram shown in FIG.
FIG. 7 is a Bode diagram showing a gain curve and a phase curve according to a transfer function obtained when the block diagram is transformed into a block diagram as shown in FIG. 6. First, the block diagram shown in FIG.
And further deformed as shown in FIG.
In FIG. 6, when the portion indicated by 61 is cut off, the transfer function of the portion indicated by 62 is

[0033]

(Equation 7)

However, if the portion indicated by 61 is connected, the transfer function of the portion indicated by 62 is

[0035]

(Equation 8)

## EQU1 ## FIG. 2 shows the transfer function G (S) described above.
When realized by a high-pass filter having the characteristics shown in FIG. 5, the transfer function G (S) is 0 [dB] in a high frequency range.
Therefore, in FIG. 6, the transfer function of the portion indicated by 62 is

[0037]

(Equation 9)

## EQU4 ## For the sake of simplicity, if T _M = 1, the above equation (7) becomes 1 / J _M and the above equation (9) becomes (1 / J _M ) / (1 + 1 / J _M ). Therefore, the frequency W0 [rad / se] at which the acceleration feedback is effective
c], the equivalent inertia of the motor is (1)
+ 1 / J _M ) times larger. In the characteristic shown in FIG. 4, the influence of the acceleration feedback occurs near the frequency W0 [rad / sec].

Here, returning to FIG. 4, reference numeral 41 denotes a gain curve, and this gain curve 41 has characteristics similar to the gain curve 31 shown in FIG. 3 in a low frequency band. On the other hand, since acceleration feedback is applied in a high frequency range, the gain at a slope of −20 dB / dec in the gain curve 41 in the high frequency range is set to 1 rad / sec.

[0040]

(Equation 10)

## EQU1 ## Also, the point 41a of the gain curve 41
Indicates a resonance point, and the resonance point 31a is

[0042]

[Equation 11]

Is near. Point 41b of gain curve 41
Indicates an anti-resonance point, and this anti-resonance point 41b is

[0044]

(Equation 12)

Is as follows.

Embodiment 2 In the first embodiment, a signal obtained by multiplying the motor acceleration signal by the transfer function G (S) is fed back to the current command signal. In the second embodiment, the motor acceleration signal is calculated from the motor speed signal by a calculation process. And a signal obtained by multiplying the motor acceleration signal by the transfer function G (S) is fed back to the current command signal.

Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. FIG. 7 is a block diagram of a drive control device for a servo system according to the second embodiment. In FIG. 7, 3
Is a block showing the proportional gain K _V , 17 is a speed compensator as speed compensating means having the gain K _{V of the} block 3,
5 is a block showing a torque constant T _M , and 6 is a block showing a motor having inertia J _M. This block 6
Will be described as including the motor and a speed detector as speed detecting means. 8 is an integrator for calculating the rotational position of the motor, and 9 is the rigidity K _L between the motor and the load.
Is a block showing the load of the inertia J _L , 11 is a block showing an integrator for calculating the position of the load, and 12 is a motor speed signal Y (S).

Reference numeral 16 denotes a motor acceleration signal obtained by differentiating the motor speed signal 12 from the speed detector included in the block 6. Based on the motor acceleration signal, the inertia of the motor is not changed within the response band of the servo system. , A transfer function G (S) as inertia control means for controlling so as to increase an equivalent inertia of the motor outside a response band of a servo system including a resonance point between the motor and a structure driven by the motor.
And a differential element S. 1a is a subtractor for calculating the difference between the speed command signal U (S) as an input value and the motor speed signal 12, 1b is a subtractor for calculating the difference between the output of the speed compensator 17 and the output of the block 16, 7a Is a subtractor for calculating the difference between the output of the block 5 and the output of the block 9, and 7b is a subtractor for calculating the difference between the output of the block 8 and the output of the block 11.

1 is a subtractor 1a, 1b, 7a, a speed compensator 17, a torque constant T _M (block 5), a motor and speed detector (block 6), a transfer function G (S) and a differential Figure 7 shows a speed minor loop comprising the product of elements S (block 16). The minor loop 1 of this speed feeds back the signal from the block 16 to the current command signal. 7 includes a motor and a speed detector (Block 6) and an integrator (block 8) and a subtractor 7a, 7b and rigidity K _L (block 9) and the load (block 10) and an integrator (block 11) configured 1 shows a structure model to be used.

Next, the operation will be described. In the speed minor loop 1, the speed command signal U (S), which is the input value of the speed minor loop 1, is compared with the motor speed signal 12 from the block 6 by the subtracter 1a, and the error is calculated to correct the speed. To the vessel 17. The error given to the speed compensator 17 is P-compensated by the proportional gain K _V (block 3), and becomes a current command signal. This current command signal is included in a block 6 and is obtained by multiplying a signal obtained by multiplying a motor speed signal 12 detected by a speed detector attached near the motor by S · G (S) of a block 16 and a subtractor 1b. The error is calculated, and the error is then multiplied by a torque constant T _M (block 5) to provide the input torque signal for the structure model 7.

As described above, in the second embodiment, the rotation speed of the motor is detected by the speed detector attached near the motor, and a signal obtained by multiplying the rotation speed by SG (S) is given by the current command. A minor loop 1 having a speed for feeding back to a signal is provided. By feeding back the signal output from the SG (S) to the current command signal, the signal is out of the response band of the servo system (higher than the response band).
It is possible to increase the equivalent inertia of the motor on the high frequency side above a certain frequency, which makes the resonance point and the anti-resonance point of the motor and the structure closer, resulting in a lower resonance peak and stable A servo system can be obtained. Further, as a configuration, the second embodiment is simpler than the first embodiment.

[0052]

As described above, according to the first aspect, the resonance point between the rotating body and the structure is determined based on the acceleration of the rotating body without changing the inertia of the rotating body within the response band of the servo system. Since control is performed to increase the equivalent inertia of the rotating body outside the response band of the servo system including the servo system, it is necessary to provide a notch filter or the like for lowering a resonance peak between the rotating body and a structure controlled by the rotating body. Without changing the characteristics within the response band of the servo system, the resonance point and anti-resonance point of the rotating body and the structure can be brought close to each other, thereby lowering the resonance peak and obtaining a stable servo system. There is an effect that can be.

According to the second aspect, based on the acceleration calculated by the acceleration calculating means, the inertia of the rotating body is not changed within the response band of the servo system, and the rotating body and the structure driven by the rotating body. Outside the response band of the servo system including the resonance point with the object, since the apparatus is provided with inertia control means for controlling so as to increase the equivalent inertia of the rotating body, the rotating body and the structure controlled by this rotating body It is not necessary to provide a notch filter for lowering the resonance peak with the object, and the resonance point and anti-resonance point between the rotating body and the structure can be made closer without changing the characteristics within the response band of the servo system. Thus, there is an effect that the resonance peak is lowered and a stable servo system can be obtained.

According to the third aspect, the acceleration is obtained from the rotation speed calculated by the speed calculation means. Based on the acceleration, the inertia of the rotary body is not changed within the response band of the servo system. Outside the response band of the servo system including the resonance point with the structure driven by the rotating body, the apparatus is provided with inertia control means for controlling so as to increase the equivalent inertia of the rotating body. It is not necessary to provide a notch filter or the like to lower the resonance peak with the structure controlled by the rotating body, and the resonance point between the rotating body and the structure is not changed without changing the characteristics within the response band of the servo system. The resonance point can be made closer, whereby the resonance peak is reduced, and there is an effect that a stable servo system can be obtained.

According to the fourth aspect, as the inertia control means, the acceleration calculated by the acceleration calculation means is input, and the transmission calculated based on the frequency of the break point of the curve showing the frequency characteristic of the servo system is performed. Since the configuration including the function is used to increase the equivalent inertia of the rotating body using the transfer function, the effect of the second invention can be achieved.

According to the fifth aspect, as the inertial control means, the rotational speed calculated by the speed calculating means is inputted to obtain the acceleration, and based on the frequency of the break point of the curve showing the frequency characteristic of the servo system. Since the transfer function includes the calculated transfer function and the transfer function is used to increase the equivalent inertia of the rotating body, the effect of the third invention can be achieved.

According to the sixth aspect of the present invention, a high-pass filter that responds at a certain frequency or more outside the response band of the servo system is used as a component for generating the transfer function, and the component within the response band of the servo system is used. Since the inertia of the rotating body is not changed, a transfer function for controlling so as to increase the equivalent inertia of the rotating body outside the response band of the servo system including the resonance point between the rotating body and the structure is realized. Each of the above effects can be achieved.

[Brief description of the drawings]

FIG. 1 is a block diagram of a drive control device for a servo system according to a first embodiment of the present invention.

FIG. 2 is a Bode diagram of a simulation result showing a frequency response of a high-pass filter at a break point W0 given as an example of a transfer function G (S) of a block 13 in FIG.

3 is a Bode diagram of a simulation result showing an open-loop frequency response of the speed minor loop 1 when the output from the transfer function G (S) of the block 13 in FIG. 1 is not fed back.

4 is a Bode diagram of a simulation result showing an open-loop frequency response of the speed minor loop 1 when the output from the transfer function G (S) of the block 13 in FIG. 1 is fed back.

FIG. 5 is a block diagram obtained by modifying the block diagram shown in FIG. 1;

FIG. 6 is a block diagram obtained by further modifying the block diagram shown in FIG. 5;

FIG. 7 is a block diagram of a drive control device for a servo system according to a second embodiment of the present invention;

FIG. 8 is a block diagram of a conventional drive control device for a servo system.

[Explanation of symbols]

1 Speed minor loop, 1a, 1b, 7a, 7b
Subtractor, 2, 17 Speed compensator (speed compensating means), 3
Block showing a proportional gain, 5 block showing a torque constant, 6 block showing a motor (rotating body) and a speed detector, 7 structural model, 8 block showing an integrator for calculating the rotational position of the motor, 9 motor and load Block showing rigidity between 10, block showing load, 11
Block showing integrator to calculate load position, 12Y
(S) motor speed signal, 13 block showing transfer function (inertial control means), 14 block showing integrator for calculating motor rotation speed (speed calculating means), 15 motor acceleration signal, 16 differential element and transfer function Block indicating product (inertial control means), 18 block indicating motor and acceleration detector (acceleration calculating means), 19 U (S) speed command signal.

Claims (6)

[Claims] 1. A servo system including a resonance point between the rotating body and a structure driven by the rotating body without changing the inertia of the rotating body within a response band of the servo system based on the acceleration of the rotating body. A drive control device for a servo system, wherein the control is performed so as to increase the equivalent inertia of the rotating body outside the response band of (1). 2. A drive control device for a servo system which aims to cause a rotation speed of a rotating body to follow a command value by a minor loop. Speed calculation means for calculating the rotation speed of the rotation and feedback to the speed compensation means, acceleration calculation means for calculating the acceleration of the rotating body,
Based on the acceleration calculated by the acceleration calculating means, the servo including the resonance point of the rotating body and a structure controlled by the rotating body without changing the inertia of the rotating body within the response band of the servo system. A drive control device for a servo system, comprising: inertia control means for performing control so as to increase an equivalent inertia of the rotating body outside a response band of the system. 3. A drive control device for a servo system which aims to make the rotation speed of a rotating body follow a command value by a minor loop. A speed calculating means for calculating the rotation speed of the rotating body and feeding back to the speed compensating means; and obtaining an acceleration from the rotation speed calculated by the speed calculating means. Inertia control means for controlling so as to increase an equivalent inertia of the rotating body outside a response band of a servo system including a resonance point of the rotating body and a structure controlled by the rotating body without changing inertia. A drive control device for a servo system, comprising: 4. The inertial control means includes an input of an acceleration calculated by the acceleration calculating means, and a transfer function calculated based on a frequency at a break point of a curve indicating a frequency characteristic of a servo system. 3. The drive control device for a servo system according to claim 2, wherein: 5. The inertial control means calculates the acceleration by inputting the rotation speed calculated by the speed calculating means, and calculates the acceleration based on the frequency of a break point of a curve indicating the frequency characteristic of the servo system. The drive control device for a servo system according to claim 3, further comprising a transfer function. 6. The servo according to claim 4, wherein a high-pass filter that responds at a certain frequency or higher outside a response band of a servo system is used as a component for generating the transfer function. System drive controller.