JP3196266B2 - Motor speed control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor speed control device in a two-inertia system in which a motor and a load are connected by an elastic shaft.

[0002]

2. Description of the Related Art In an elevator, a steel rolling mill, a robot arm, or the like, when a motor and a load are connected by a shaft having low rigidity, a shaft torsional vibration occurs and the response of a speed control system can be increased. There is a problem of disappearing. In such a two-inertial torsional vibration system, a pulse encoder is used as a speed detector of the electric motor. Therefore, the encoder pulse interval becomes longer than the speed control cycle in the extremely low speed range of the electric motor. If this cycle becomes longer, accurate speed information cannot be obtained, and there is a problem that the speed control system becomes unstable.

[0003]

There are various methods for suppressing a two-inertial torsional vibration system (A: Japanese Patent Application No. 3-6).
No. 8125, B: Japanese Patent Application No. 3-88030). Japanese Patent Application No. 3-114229 discloses a method for improving the characteristics of a speed control system using a pulse encoder in an extremely low speed range. However, it is very difficult to improve the above two problems at the same time. The observer in the latter characteristic improvement method also has a load disturbance compensation function by adding the estimated load torque value simultaneously estimated to the output of the speed amplifier.
When this speed estimation observer is applied to a two inertia torsional vibration system, the motor speed and the load speed are different (described in the former A). To estimate the motor speed, the model machine time constant of the observer is set to the motor machine time constant. There is a need to.
Therefore, the torque estimated value obtained by the speed estimation observer becomes the shaft torque estimated value. Even if the disturbance compensation is performed by adding the estimated shaft torque value to the output of the speed amplifier, there is almost no effect. To perform disturbance compensation, it is necessary to estimate the load torque as shown in the former A. As described above, in order to estimate the load torque of the two-inertia system, all state quantities (motor speed, shaft torque, disturbance torque, and load speed) must be estimated by the observer from the state equation of the two-inertia system. For this reason, the configuration of the observer is complicated in the above-mentioned method, and there is a problem that it is extremely difficult to put the observer to practical use.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has been developed to improve the speed control characteristic of a two inertia torsional vibration in an extremely low speed range by combining a speed estimation observer and a load torque estimation observer. It is an object to provide a control device.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is directed to a first invention in which a two-inertia torsional vibration system is used.
The angular velocity of the motive is measured by a speed detector consisting of a pulse encoder.
In the speed control system of the motor to be detected and used,
Pulse interval from pulse encoder is longer than speed control cycle
Zero speed observing motor speed in extremely low speed range
Observer and motor speed obtained by this zero-speed observer
Load torque estimate is supplied and the load torque estimate approximates the output
Load torque estimating observer section for sending
Estimated motor speed obtained by buzzer and motor speed
A first deviator for obtaining a deviation from the command value, and
Amplifier that amplifies the deviation output from the speed amplifier
Output and load torque estimation
Add the load torque estimated value and give a torque command to the motor.
A zero-speed observer unit, and a torque finger.
And a second deviator for calculating a deviation between the command and the estimated shaft torque.
Obtain the deviation output of the second deviator using the observer model machine time constant
A first operation unit that integrates and obtains a model output estimated value at an output;
From the model output estimated value obtained by the first calculation unit,
A second operation unit for obtaining an average value in the interval, and the second operation unit
When the output of the unit and the pulse output from the speed detector change.
A third deviator for calculating a deviation from the average speed,
Multiply the deviation value obtained by the third deviator by the observer gain
An observer gain unit for obtaining the shaft torque estimated value;
The model output estimate is supplied to the plus terminal,
The deviation from the deviation output of the third deviation device supplied to the
And a fourth deviator for outputting as an estimated value.
The load torque estimation observer unit calculates the torque command and load torque.
A fifth deviator for calculating a deviation from the estimated value;
Integrate the deviation output with the observer model machine time constant and output
And a third operation unit for obtaining a model output estimated value
The model output estimate obtained by the
Speed output from the zero-speed observer unit to the terminal
A sixth deviator to which a value is supplied and an output of the sixth deviator
The obtained deviation output is multiplied by the observer gain, and
Obtain Gay Obtaining Output Torque Estimated Value Given to Vehicle
It consists of a

According to a second aspect of the invention , the speed amplifier is composed of a proportional-integral element.

[0007]

The speed estimation in the extremely low speed range is performed by the zero-speed observer to obtain an estimated speed value. This speed estimation value is used as a feedback amount of the speed amplifier and also as a speed detection value of the load torque estimation observer. The load torque estimation value obtained by the load torque estimation observer is added to the output of the speed amplifier to perform torque compensation of the electric motor to suppress torsional vibration.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. First, a model of a two-inertia system shown in FIG. In FIG. 1, τ _M is the generated torque of the motor, τ _S is the shaft torque, τ _L is the load torque, ω _M is the angular velocity of the motor, ω _L
Is the angular velocity of the load, θ _M is the angular displacement of the motor, θ _L is the angular displacement of the load, T _M is the mechanical time constant of the motor, _TL is the mechanical time constant of the load, T _S is the spring time constant of the shaft, T _S = 1 / Km. Here, the following equation of motion is obtained from the two inertial model shown in FIG.

[0009]

(Equation 1)

The above equation (3) can be expressed as the following equation (4).

[0011]

(Equation 2)

FIG. 2 is a block diagram of a two-inertia system using the above equation (4).

Next, an embodiment of the present invention will be described with reference to FIG. Reference numeral 11 denotes a first deviator, which obtains a deviation between the speed command ω _M * (i) of the electric motor and an estimated speed value obtained from a zero-speed observer, which will be described later. This deviation is amplified by the speed amplifier 12 and supplied to the adder 13. The adder 13 adds a load torque estimation value obtained from a load torque estimation observer, which will be described later, to obtain a torque command τ _M * of the two inertial system model 14. The angular velocity ω _M of the electric motor of the two inertial system model 14 is detected by a speed detector 15 including a pulse encoder. The speed detected by the speed detector 15 is supplied to the next zero speed observer 16 as an average speed.

The zero-speed observer section 16 is configured as follows. Reference numeral 161 denotes a second deviator for calculating a deviation between the torque command τ _M * (i) and the estimated value of the shaft torque.
The deviation output of 61 is input to the first calculation unit 162. The first calculation unit 162 includes a division unit 162a that divides the speed control cycle T _S by a model machine time constant T _M *, and a division unit 162a.
It comprises an adder 162c that adds the output of 2a and the output of integrator 162b. The model output estimated value calculated by the first calculation unit 162 is input to the second calculation unit 163 for obtaining an average value at the pulse interval. The output calculated by the second calculation unit 163 is supplied to a plus input terminal of the third deviation unit 164, and an average speed of the speed detection output detected by the speed detector 15 is supplied to the minus input terminal. .

The deviation output of the third deviation unit 164 is supplied to an observer gain unit 165, where it is multiplied by a predetermined value to obtain an estimated shaft torque value in the output. Further, the deviation output of the third deviation device 164 is supplied to the minus input terminal of the fourth deviation device 166. A model output estimated value is supplied to a plus input terminal of the fourth deviator 166, and a speed estimated value is obtained from the output.
The estimated speed value is supplied to a minus input terminal of the first deviation unit 11 and a load torque estimation observer unit 17 described later.

Reference numeral 17 denotes a load torque estimating observer. The load torque estimating observer 17 is configured as follows. A fifth deviator 171 calculates a deviation between the torque command τ _M * (i) and the estimated load torque.
The deviation output of 1 is input to the third calculation unit 172. The third calculation unit 172 includes a division unit 172a that divides the speed control cycle T _S by the model machine time constant T _m *, and a division unit 172.
adder 1 that adds the output of a and the output of integrator 172b
72c. The model output estimated value calculated by the third calculation unit 172 is supplied to the plus input terminal of the sixth deviation unit 173. The estimated speed value output from the zero speed observer unit 16 is supplied to the minus input terminal of the sixth deviation unit 173. The deviation output of the sixth deviation unit 173 is supplied to an observer gain unit 174, where it is multiplied by a predetermined value (K ₀ times).
To obtain a load torque estimate at the output. This load torque estimated value is supplied to the adder 13.

In the embodiment configured as described above,
The model machine time constant T _M * of the zero-speed observer unit 16 is set to the motor machine time constant T _M. The model mechanical time constant _Tm * of the load torque estimation observer unit 17 is set to the sum of the mechanical time constants of the motor and the load ( _TM + _TL ). After these settings, the zero speed observer 16 estimates the speed in the extremely low speed range, and obtains the estimated speed from the fourth deviation unit 166. This speed estimation value is used as a feedback amount of the speed amplifier 12 and also as a speed detection value of the load torque estimation observer unit 17. As a result, the load torque estimation value obtained from the load torque estimation observer unit 17 is given to the adder 13 and added to the output of the speed amplifier 12, and the torque of the two-inertia model 14 is compensated by the added output. The suppression can be performed. Thus, by combining the zero-speed observer unit 16 and the load torque estimation observer unit, it becomes possible to suppress the two inertial torsional vibrations in the extremely low speed range.

[0018]

[0019]

[0020]

As described above, according to the present invention,
When a pulse encoder is used as the speed detector of the two-inertia torsional vibration system, it is possible to estimate the speed in an extremely low speed range and suppress the torsional vibration, so that the speed control system can be stabilized.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a model of a shaft torsional vibration system,

FIG. 2 is a block diagram of a shaft torsional vibration system,

FIG. 3 is a block diagram showing one embodiment of the present invention;

[Explanation of symbols]

11: first deviation device, 12: speed amplifier, 13: adder,
14 ... 2 inertia model, 15 ... speed detector, 16 ... zero speed observer unit, 17 ... load torque estimation observer unit.

Claims (2)

(57) [Claims] 1. The angular velocity of an electric motor of a two inertia torsional vibration system
In speed control system of a motor utilizing is detected by the speed detector including a pulse encoder, a zero speed observer unit that estimates a motor speed at an extremely low speed range where the pulse interval is longer than the speed control period from the pulse encoder, the A motor torque estimated value obtained by the zero-speed observer unit is supplied, and a load torque estimation observer unit that outputs a load torque estimated value approximate to the output; a motor speed estimated value obtained by the zero-speed observer unit; A first deviator for obtaining a deviation from the speed command value of the first
Comprising a speed amplifier for amplifying the differential output from the differential unit, an addition unit for the output of the speed amplifier and by adding the load torque estimated value sent from the load torque estimating observer unit providing a torque command to the motor, wherein The zero-speed observer is a torque command and shaft torque estimated value.
A second deviator for calculating a deviation from the second deviator, and a deviation output of the second deviator.
The force is integrated with the observer model machine time constant, and the output is modeled.
A first operation unit for obtaining an estimated output value, and a first operation unit for obtaining the estimated output value.
Average at the pulse interval from the estimated model output
, And the output of the second calculator and the speed detection
Of the average speed obtained when the pulse output from the
A third deviator for calculating the deviation, and
Is multiplied by the observer gain to obtain the estimated shaft torque value.
And an observer gain section for obtaining
The positive terminal and the negative terminal
Outputs the deviation from the deviation output of the third deviation device as the speed estimation value
The load torque estimating observer unit is configured to output a torque command and a load command.
A fifth deviator for calculating a deviation from the estimated torque value,
Integrate the deviation output of the differentiator with the observer model machine time constant
And a third operation unit for obtaining a model output estimated value as an output,
The model output estimated value obtained by the third arithmetic unit is a plus terminal
Output to the minus terminal from the zero-speed observer section.
A sixth deviation device to which the estimated speed value is supplied;
Observer gain multiplied by the deviation output obtained from the detector output
Obtain the output torque estimated value to be given to the adder as an output.
A speed control device for an electric motor , comprising a server gain unit . 2. The motor speed control device according to claim 1, wherein the speed amplifier comprises a proportional integral element.