JPH10155292A - Two-inertial system control circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve characteristics in a very low speed range. SOLUTION: This controlling circuit is made up of a speed amplifier 2, which amplifies speed deviation, a load torque observer 31 for controlling disturbance, which presumes a load torque from the output of this amplifier and speed signal to output two-inertial system torque commands, a resonance proportional control circuit 51 for controlling vibration, which multiplies the torque command from this observer in proportion to resonance and presumes a torque from the signal multiplied in proportion to the resonance and speed signal to output a motor torque command to two-inertial system 8, and a speed detector 91 , which detects four edge signals of the A phase and B phase signals with the rotary encoder and outputs pulses overlapped with these signals as a speed signal. The shortened cycle of this speed signal makes it possible to restrain the vibration in a very low speed range. Even if the speed information is interrupted in the very low speed range, the circuits 31 , 51 presume the speed using a model speed so that speed can be controlled smoothly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-inertial-system control circuit with improved low-speed characteristics.

[0002]

2. Description of the Related Art As shown in FIG. 12 (a), when a torque is applied to a motor M in a two inertia system in which a motor M and a load L are connected by an elastic shaft S, vibration may occur. Various control methods have been proposed for suppressing vibration of the two inertial system.

A two-mass system can be modeled as shown in FIG. In the figure, F _M is the motor transfer function for outputting a speed omega _M receives the difference torque of the motor torque command tau _M and the shaft torque τ _S, F _S receives the speed difference between the motor speed omega _M and the load speed omega _L elastic shaft transfer function for outputting a shaft torque tau _S Te, F _L is the load transfer function of outputting the load speed omega _L receives the difference torque shaft torque tau _S and disturbance torque tau _L.

[0004] Speed control system using this model as shown in FIG. 13, the speed command n _L * and the motor detection speed n _M ^- a and deviation between the speed amplifier 2 to PI calculation, it outputs a detection speed of the amplifier 2 , A vibration suppression circuit 5 that inputs the output of the circuit 3 and the detected speed, and outputs a motor torque command τ _M to the two inertial resonance system 8, and a speed detector 9.

[0005] disturbance suppression circuit 3 intended to suppress the rapid change (disturbance) of the load due to the external force, it can be composed of a load torque observer minimum dimension or completely dimension as indicated by reference numeral 3 ₁ of Figure 1.

As shown in FIGS. 14 to 16, the vibration suppression circuit 5 includes a resonance ratio control circuit, a resonance ratio control + first-order lag compensation filter circuit, a low inertia control circuit, and the like. It has a minimum or full dimension axial torque observer 506 to be estimated.

In the resonance ratio control circuit of FIG. 14, when the output of the shaft torque observer 506 is K, a constant for keeping the ratio between the resonance frequency of the two inertial resonance system 8 and the anti-resonance frequency constant is K ( K-1) Resonance ratio gain circuit to double 505
And a gain circuit 502 that multiplies the output τ _i of the disturbance suppression circuit (FIG. 13) by the resonance ratio gain to obtain the motor torque command τ _M
Is a control method. The feature of this control method is that the ratio of the resonance frequency to the anti-resonance frequency of the two inertial resonance system is set to a constant value so that vibration is less likely to occur, and the vibration is suppressed by high-speed estimation of shaft torque.

The circuit shown in FIG. 15 in which the first-order lag compensation is applied to the resonance ratio control has a structure in which a first-order lag compensation filter 501 is inserted in the input stage of the resonance ratio control.
Even if the cut-off frequency of 06 is low, the cut-off frequency can be apparently increased to compensate for vibration suppression characteristics. (The Institute of Electrical Engineers of Japan, IEA Technical Paper
-94-12P.1, Japanese Patent Application No. 6-276167) The low inertia control circuit of FIG.
By inserting the element 04 as shown in the figure, the compensation effect is higher than in the case of FIG. 15 in which a first-order lag filter is applied to the resonance ratio control. When the first-order lag compensation filter is applied to the resonance ratio control or the resonance ratio control, the gain circuit 502 and the first-order lag compensation filter 501 are inserted between the disturbance suppression circuit (FIG. 13) and the torque command τ _M to the motor. However, nothing is inserted in the low inertia control. This makes it easy to switch the output of the vibration suppression circuit on and off, and it is possible to smoothly stop and restart the vibration suppression circuit in an extremely low-speed range described later. (1995 IEEJ National Convention No. 869, Japanese Patent Application No. 6-657)
63, Japanese Patent Application No. 6-271645) The above control system has been discussed in a continuous time system. However, in practice, it must be a discrete time system because it is realized by software. Further, the speed detector 9 shown in FIG.
Is also a discrete-time system. The calculation cycle of the control system and the detection cycle of the motor speed are not synchronized but have independent cycles. Therefore, if the motor rotates at a high speed and the speed detection cycle is shorter than the control cycle, a continuous speed signal is obtained, so no problem occurs. If the period becomes longer than the control period, an accurate speed cannot be detected, causing a problem that the control system becomes unstable (FIG. 18).

In order to improve the characteristics in the extremely low speed range, the following method is adopted as a speed detection method.
Usually, a rotary encoder is used for speed detection.
The output of the rotary encoder is as shown in FIG.
In this method, a pulse of one period of the A-phase or B-phase signal called the f system is picked up and the speed is calculated. This is accurate, but the speed detection cycle becomes longer, so that the speed detection cycle becomes longer than the control cycle in the extremely low speed range, and the speed calculation becomes coarse, so that the speed system becomes unstable.

There is also a so-called 4f system,
Although there is a method using both pulse information of the phase signal and the pulse signal of the B phase, accurate speed detection cannot be performed due to an accuracy error of the phase difference between the A phase signal and the B phase signal. In order to solve these problems, an overlap speed detection method which combines the advantages of the 1f method and the 4f method has been proposed (IEEJ-94-16, IEEJ, IEA-94-16.
P.37).

The overlap speed detection method is a method in which four edge signals are overlapped as shown in FIG. 19 and a signal having an accuracy of 1f can be detected at a period of 4f. According to this method, it is possible to stably control the rotational speed up to 1/4 of the conventional control method.

In the discrete-time system, the calculation cycle of the model speed of the observer and the speed detection cycle of the motor are not synchronized, so that the difference calculation cannot be performed as it is. Therefore, it is necessary to perform an averaging process.

The principle of the averaging process is as shown in FIG.
The average of the model speed or the detected speed is calculated at the time of synchronizing with the speed detection period or the speed control period, and the difference is calculated at the same time. (Institute of Electrical Engineers of Japan, IEA-94-16, page 37) At extremely low speeds, the waveform detected by the above-described speed detection method is as shown in FIG. 21, but includes load torque observers and shaft torque observers. In the control system of FIG. 13, this step-like change in the detected speed has the same function as a sudden change in the load torque or the shaft torque, and the control system becomes unstable, so that the observer gain cannot be increased. If the speed detection period is longer than the speed control period, the pause period of the signal becomes a dead time, which also becomes an unstable factor.

For this reason, as shown in FIG. 22, the speed is estimated using the model speed of the observer and the detected speed value (Electronics Theory D, Vol. 115, No. 11, 1995, p. 1316). Then, the speed estimation value becomes a smooth value even during the pause period of the signal as shown in FIG. By using this as an input of a speed feedback or an observer instead of the detected speed value, smooth speed control can be performed even at an extremely low speed.

[0015]

The conventional vibration suppression circuit is designed on the assumption that the motor speed can be continuously obtained, and the vibration suppression characteristic is deteriorated by discrete speed detection changes in an extremely low speed range. In addition, the vibration suppression circuit may generate disturbance torque.

The present invention has been made in order to solve such a conventional problem.
The speed detection method shown in FIGS. 19 and 20 and the load torque observer and the vibration suppression circuit for improving the characteristics in an extremely low speed range are described.
An object of the present invention is to provide a two-inertial-system control circuit in which two circuits are combined to enable smooth speed control even in an extremely low speed range.

[0017]

A two-inertia control circuit according to the present invention includes a speed amplifier for amplifying a deviation between a speed command and a speed signal, and a load amplifier for estimating a load torque from an output signal and a speed signal of the amplifier. A load torque observer for disturbance suppression that outputs an inertia system torque command, a torque ratio from the observer is multiplied by a resonance ratio, and a shaft torque is estimated from a signal of the resonance multiplied and a speed signal to provide a motor torque command to a two inertia system. A vibration suppression resonance ratio control circuit or a vibration suppression low inertia reduction control circuit for estimating a shaft torque from a torque command and a speed signal from the observer and outputting a motor torque command to a two inertia system; It comprises a speed detector which detects four edge signals of the A-phase signal and the B-phase signal using an encoder and outputs an overlapped pulse as the speed signal.

When a resonance ratio control circuit is used for suppressing vibration, a first-order lag compensation filter is applied to the preceding stage.

Further, it is preferable to provide a means for cutting off the vibration suppressing circuit in an extremely low speed range and controlling the two inertia system by a torque command from a load torque observer.

In this case, means for estimating the speed using the model speed of the load torque observer in an extremely low speed range may be provided, and the estimated speed signal may be used as a feedback signal to the speed amplifier.

Alternatively, a means for performing speed estimation using the motor model speed of the vibration suppression circuit may be provided, and the estimated speed signal may be used as a speed signal of the load torque observer or a feedback signal to the speed amplifier.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. 1 shows a speed control system of a two-mass vibration system. In the figure, 1 is the speed command value n _L * and the speed detection value n _M ^- deviation detector for detecting a deviation between the two speed amplifier for amplifying the deviation, 3 ₁ connected disturbance suppression circuit in the amplifier load torque observer as, 5 ₁ resonance ratio control circuit as the vibration suppression circuit for outputting a two-inertia torque command tau _ML * receiving and two-inertia (vibration) system 8 torque command tau _M * from the observer, 9 Reference numeral ₁ denotes a speed detector for detecting a motor speed by the overlap speed detection method shown in FIG.

The load torque observer 3 ₁ includes an adder 31 for outputting to 2 inertia torque command tau _M * adds the torque command and the load estimated value Z _L ∧ estimated by the observer from the speed amplifier 2, the torque command Delay circuit 32 for obtaining the previous value of
, A subtractor 33 for taking the difference between the previous value of the torque command and the load estimated value, a two inertia model 34 to which a difference signal from the subtractor is inputted, an adder connected to this model, A delay circuit that obtains the previous value of the signal from the adder and outputs it to the adder 35; an average value processing circuit 37 that calculates the average value of the two inertial model speeds n _ML ′} from the adder 35; mean values and the speed detection value n _M ^- a subtracter 38 for obtaining a difference between, and a observer gain circuit 39 for outputting the load estimated value Z _L ∧ the difference signal by K _L times.

Further, the resonance ratio control circuit 5 ₁ includes a gain circuit 52 is multiplied by K to the 2-inertia system the ratio of the resonant frequency and the antiresonant frequency of the torque command 2-inertia system from the load torque observer 3 ₁ constant , the shaft torque estimate tau _S ∧ estimated by the resonance ratio control circuit 5 _{1 (K-1)} multiplying the gain circuit 5
5, a subtractor 56 for obtaining the difference between the two-inertia-system torque command and the estimated shaft torque value and outputting a motor torque command τ _M * to the two-inertia system 8, and a delay circuit 5 for obtaining the previous value of the torque command
7, a subtracter 58 for obtaining a difference between the axial torque estimation value estimated by the previous value and the circuit 5 _1, the motor model 59 this difference signal is input, connected to this model adders 6
0 and the previous value of the signal from the adder are obtained to determine
0 and a averaging circuit 6 for calculating the average value of the motor model speed n _M ′ ∧ from the adder 60.
2, the motor model speed average value and the speed detection value n _M ^- observer outputs a subtractor 63 for obtaining a difference between, the difference signal K _S multiplying the shaft torque estimate τ _{S (i)} ∧ It is composed of a gain circuit 64.

[0025] As described above, since the use a of overlap speed detection method as a speed detector 9 _1, vibration suppression in the slow can be shortened speed detection period can be realized. Moreover, even if there is a period of rest to the speed information from the speed detector 9 ₁ in an extremely low speed region, since the load torque observer 3 ₁ speed estimation is made by using the model speed with load torque estimate, smooth speed Speed control can be performed smoothly as information. Similarly, to facilitate the speed control by using the well model speed resonance ratio control circuit 5 _1.

Embodiment 2 In FIG. 2, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and redundant description is omitted. 2, 5 ₂ is a resonance ratio control + first order lag compensation filter circuit for outputting a torque command to the load torque observer 3 connected 2-inertia system 8 to _1. In that provided first-order delay compensation filter 51 at the preceding stage of the circuit 52, the resonance ratio control circuit 5 ₁ of FIG. 1
It is different from that. Other circuit configuration is shown in FIG.
There is no difference from the one.

[0027] Since the circuit 5 ₂ in the resonance ratio control circuit 5 ₁ of FIG. 1 has a one in which a first-order delay compensation filter 51, apparently observer by appropriately selecting the time constant of the filter (5 ₁ Since the cutoff frequency can be increased, resonance does not occur even when the observer gain is small as compared with the circuit of FIG.

[0028] For Embodiment 3 FIG. 3 embodiment, 5 ₃ are connected to the load torque observer 3 _1, a low inertia control circuit for outputting a torque command to the 2-inertia system 8. The circuit 2 from torque observer _{3 1}
First-order lag compensation filter 53 to which an inertia torque command is input
When, a subtracter 54 for outputting to the gain circuit 55 takes the difference between the signals from the shaft torque estimate the first order lag compensation filter 53 from the observer gain circuit 64 is provided, subtracter from the load torque observer 3 ₁ 2 The difference between the inertia torque command and the signal from the resonance ratio gain circuit 55 is calculated to obtain a two-inertia system 8.
₁ is different from the resonance ratio control circuit 51 of FIG. Other circuit configurations are the same as those in FIG.

[0029] The circuit 5 _3, resonance ratio control circuit 5 ₁ of FIG. 1
Similarly, the shaft torque is estimated by the circuits 57 to 64 and the subtractor 5
6 outputs a torque command. Since the estimated torque value input to the gain circuit 55 is compensated by the first-order lag compensation filter 53 by the second-order inertia command with the first-order lag, low inertia control can be performed.

[0030] For Embodiment 4 FIG. 4 embodiment, 5 ₄ are resonance ratio control circuit connected to the load torque observer 3 _1. This circuit is a gain circuit 52
Has become one that differs from the resonance ratio circuit 5 ₁ of FIG. 1 in which a bypass switch SW ₁ for very low speed under the bypass series circuit of a subtractor 56 and. Other circuit configurations are the same as those in FIG.

[0031] The circuit 5 _4, switch SW ₁ pole at low speed
Is turned on to bypass the resonance ratio circuit, so that erroneous control of the resonance ratio circuit in an extremely low speed range where the speed detection pulse does not enter can be eliminated.

[0032] For Embodiment 5 FIG. 5 embodiment, 5 ₅ is a resonance ratio control + first-order lag filter circuit connected to the load torque observer 3 _1. This circuit differs with first order lag compensation filter 51 and gain circuit 52 and the resonance ratio control + first-order lag filter circuit 5 ₂ of Figure 2 at a point a switch SW ₁ for a very low speed under the bypass series circuit of a subtractor 56 It has become something. Other circuit configurations are the same as those in FIG.

[0033] The circuit 5 _5, switch SW ₁ pole at low speed
Is turned on to bypass the resonance ratio control + first-order lag filter circuit, it is possible to eliminate erroneous control of the resonance ratio control + first-order lag filter circuit in an extremely low speed region where a speed detection pulse does not enter.

[0034] For Embodiment 6 FIG. 6 embodiment, 5 ₆ is a low inertia control circuit connected to the load torque observer 3 _1. This circuit is a gain circuit 5
5 and between the subtractor 56 in that a switch SW ₂ cut at low speed is different from the low inertia of the control circuit of FIG. Other circuits are the same as those in FIG.

The circuit 5 ₃ operates at a very low speed when the switch SW ₂
Since There the output of the gain circuit 55 to OFF disappears adder 56 outputs the output of the load torque observer 3 ₁ as it is to the 2-inertia system, low inertia Control in an extremely low speed range so as not not enter the speed detection pulse Erroneous control of the circuit can be eliminated.

[0036] The seventh FIG seventh embodiment, 4 subtracter for outputting the difference signal takes a difference between the signals from the load torque observer 3 ₁ adders 35 and 38 to the deviation detector 1, 5 vibration suppression circuit (5 ₄ ~
In step 5 ₆ ), no output is made by the switch (SW ₁ or SW ₂ ). Other circuit configurations are the same as those in FIGS.

The adder 35 outputs the two inertia model speed,
The adder 38 outputs a difference signal between the average value of the two inertial model speeds and the speed detected by the speed detector 9, so that the speed estimate is obtained from the subtractor 4. Since the circuit in FIG. 4 performs speed control based on the estimated speed value, speed control at an extremely low speed is possible.

[0038] The eighth 8 embodiment, 7 ₁ resonance ratio control circuit 5 _first adder 60 and takes the difference between the signals from the 63 deviation detector and the difference signal 1
And a subtracter for outputting a load torque observer 3 _1. Other circuit configurations are the same as those in FIG.

The adder 60 outputs the motor model speed,
Since the adder 63 outputs the difference between the detected speed from the motor model speed average value and the speed detector 9 speed, the speed estimated value is obtained from the subtracter _71, the circuit of FIG. 4 by the speed estimation value Since control is performed, speed control at an extremely low speed becomes possible.

[0040] The ninth 9 embodiment, 7 ₂ resonance ratio control + first-order lag filter circuit 5 _second adder 60 and takes the difference between the signals from the 63 deviation detector and the difference signal 1 and the load torque observer 3 Subtractor that outputs ₁ Other circuit configurations are the same as those in FIG.

[0041] Since the velocity estimates as well as the adder 7 ₁ 8 is obtained from the adder 7 _2, it is possible to similarly pole speed control at low speeds in the case of FIG. 8.

[0042] Embodiment A 10 10 embodiment, 7 ₃ Low inertia control circuit ₃ of the adder 6
Taking the difference between the signal from the 0 and 63 is a subtracter which outputs the difference signal to the deviation detector 1 and the load torque observer 3 _1. Other circuit configurations are the same as those in FIG.

[0043] Since the velocity estimates as well as the adder 7 ₁ 8 is obtained from the adder 7 _3, it is possible to similarly pole speed control at low speeds in the case of FIG. 8.

[0044] The embodiment 11 Figure 11 embodiment, 7 ₄ low inertia control circuit 5 ₆ adder 6
Taking the difference between the signal from the 0 and 63 is a subtracter which outputs the difference signal to the deviation detector 1 and the load torque observer 3 _1. Other circuit configurations are the same as those in FIG.

[0045] Since the velocity estimates as well as the adder 7 ₁ 8 is obtained from the adder 7 _4, it is possible to similarly pole speed control at low speeds in the case of FIG. 8.

[0046]

Since the present invention is configured as described above, the following effects can be obtained.

(1) By using the overlap speed detection method, the speed detection cycle can be shortened, so that vibration suppression at low speed is realized.

(2) By turning off the vibration suppression circuit in the extremely low speed range, it is possible to eliminate erroneous control by the vibration suppression circuit in the extremely low speed range where the speed detection pulse does not enter.

(3) During the period in which the speed information from the speed detector is suspended in the extremely low speed range, the speed is estimated using the model speed of the load torque observer or the vibration suppression circuit, and smooth speed information is obtained. , Smooth speed control is possible.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an example of a control circuit according to a first embodiment.

FIG. 2 is a block diagram showing an example of a control circuit according to a second embodiment;

FIG. 3 is a block diagram showing an example of a control circuit according to a third embodiment;

FIG. 4 is a block diagram showing an example of a control circuit according to a fourth embodiment;

FIG. 5 is a block diagram showing an example of a control circuit according to a fifth embodiment.

FIG. 6 is a block diagram showing an example of a control circuit according to a sixth embodiment.

FIG. 7 is a block diagram showing an example of a control circuit according to a seventh embodiment.

FIG. 8 is a block diagram showing an example of a control circuit according to the eighth embodiment.

FIG. 9 is a block diagram showing an example of a control circuit according to a ninth embodiment;

FIG. 10 is a block diagram showing an example of a control circuit according to the tenth embodiment.

FIG. 11 is a block diagram showing an example of a control circuit according to the eleventh embodiment.

12A is a perspective view showing a two inertia system, and FIG.
FIG. 2 is a block diagram showing an inertial system model.

FIG. 13 is a block diagram showing a speed control system.

FIG. 14 is a block diagram showing an example of a conventional resonance ratio control circuit.

FIG. 15 is a block diagram showing an example of a conventional resonance ratio control + first order delay compensation filter circuit.

FIG. 16 is a block diagram showing an example of a conventional low inertia control circuit.

FIG. 17 is a pulse waveform diagram of an encoder.

FIG. 18 is a diagram illustrating a relationship between a control cycle and a detection cycle in a conventional extremely low speed range.

FIG. 19 is a timing chart illustrating an overlap speed detection method.

FIG. 20 is a graph illustrating an averaging process.

FIG. 21 is a graph illustrating a conventional speed detection method.

FIG. 22 is a block diagram showing a speed estimation circuit.

FIG. 23 is a graph illustrating the principle of speed estimation.

[Explanation of symbols]

1 ... velocity deviation detector 2 ... speed amplifier 3 ... disturbance suppressing circuit 3 ₁ ... load torque observer 34 ... 2 inertia model 37 ... averaging circuit 5 ... vibration suppression circuit 5 _1, 5 ₄ ... resonant ratio control circuit 5 ₂ , 5 ₅ ... resonant ratio control + first order lag compensation filter circuit 5 _3, 5 ₆ ... low inertia control circuit 51,501 ... first order lag compensation filter 59 ... motor model 503 ... inertia block 506 ... shaft torque observer 62 ... averaging processing circuit 8 ... 2 inertia (resonant) system 9 ... speed detector 9 ₁ ... speed detector overlap speed detection method

Claims (7)

[Claims] 1. A speed amplifier for amplifying a deviation between a speed command and a speed signal, and a load torque observer for disturbance suppression for estimating a load torque from an output signal of the amplifier and the speed signal and outputting a two-inertia torque command. A resonance ratio control circuit for vibration suppression, which multiplies a torque command from the observer by a resonance ratio, estimates a shaft torque from the signal multiplied by the resonance and a speed signal, and outputs a motor torque command to a two-inertia system; A speed detector for detecting four edge signals of the A-phase signal and the B-phase signal by using an encoder and outputting an overlapped pulse as the speed signal; . 2. The two-inertia control circuit according to claim 1, wherein a first-order lag compensation filter is applied to a stage preceding the resonance ratio control circuit to improve the vibration suppression characteristics. 3. A speed amplifier for amplifying a deviation between a speed command and a speed signal, and a load torque observer for disturbance suppression for estimating a load torque from an output signal of the amplifier and the speed signal and outputting a two-inertia torque command. A low-inertia control circuit for vibration suppression for estimating a shaft torque from a torque command and a speed signal from the observer and outputting a motor torque command to a two-inertia system; A speed detector that detects four edge signals of the phase signal and outputs overlapping pulses as the speed signal; 4. The two-inertial-system control according to claim 1, wherein the resonance-ratio control circuit is turned off in an extremely low-speed range, and means for controlling the two-inertial system by a torque command from a load torque observer is provided. circuit. 5. The two-inertia control circuit according to claim 3, further comprising means for turning off the low-inertia control circuit in an extremely low-speed range and controlling the two-inertia system by a torque command from a load torque observer. . 6. An apparatus according to claim 4, further comprising means for estimating a speed using a model speed of a load torque observer in an extremely low speed range, and using the estimated speed signal as a feedback signal to a speed amplifier. Characteristic 2
Inertial control circuit. 7. The apparatus according to claim 1, further comprising means for estimating a speed using a motor model speed of a vibration suppressing circuit, and transmitting the estimated speed signal to a load torque observer. 2. A two-inertia control circuit, wherein the control signal is a feedback signal to a speed amplifier or a speed amplifier.