JP3303566B2 - Vibration suppression device of two inertia resonance system by resonance ratio control - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration suppression device based on resonance ratio control, and more particularly to a vibration suppression device based on resonance ratio control in which a motor and a load are coupled by an elastic shaft.

[0002]

2. Description of the Related Art When an electric motor and a load are coupled by a shaft having low rigidity in an elevator, a steel rolling mill, a robot arm, or the like, a shaft torsional vibration occurs, and the response of a speed control system can be increased. There is a problem of disappearing. Shaft torsional vibration is affected by the ratio of the moment of inertia of the motor to the load, and becomes more vibratory, especially when the moment of inertia of the load is smaller than the motor, making vibration suppression control more difficult. In recent years, shaft torque has been estimated at high speed,
There has been proposed a resonance ratio (ratio between a motor resonance frequency and, for example, a robot arm resonance frequency) control means for stabilizing by lowering an apparent motor inertia by feeding back to a torque command. (Reference Document A: Electron Theory, Vol. 113, No. 10, 1993; Vibration Suppression Control of Two-Inertia Resonance System by Resonance Ratio Control) When the resonance ratio control of the above document is used, the inertia of the load is smaller than the inertia of the motor. Even in this case, a good vibration suppression effect can be obtained. However, since the disturbance suppression effect is reduced, a method of improving the disturbance suppression effect by adding a load torque observer has been proposed. (Reference B: 1993 IEEJ National Convention, 669; Resonance Ratio Control and Control of Two-Inertia System by SFC) However, resonance ratio control is performed under the assumption that the shaft torque can be estimated at high speed. Therefore, when the gain of the shaft torque observer cannot be increased, for example, when the noise of the speed detector is so large that a problem occurs when the observer gain is increased, the vibration suppression effect is reduced, and the two inertial system vibrates. Become. As a countermeasure, low inertia control has been proposed. (Reference C: IEEJ Research Material, IEA-94-12; Vibration Suppression Control of Two-Inertia Resonant System Using Low-Inertia Control) Low-inertia control is a method originally used for one-inertia system. (Reference D: 1991 IEEJ National Conference on Industrial Applications, 142; Low inertia control method using induction machine)
By applying this to a two-inertia system, the vibration suppression effect is higher than in the resonance ratio control.

[0003]

The resonance ratio control is based on the assumption that the shaft torque can be estimated at high speed.
If the observer gain cannot be made sufficiently large, the vibration suppression effect will be reduced. In addition, the low inertia control has a feature that, even when a first-order lag filter is inserted in the input stage of the observer in a feed-forward manner and the observer gain cannot be sufficiently increased, it exhibits a good vibration suppression effect. The theoretical effect of the delay filter has not been elucidated, and the time constant of the filter has only been obtained analytically using a root locus or the like.

The present invention has been made in view of the above circumstances, and enables the time constant of a first-order lag filter to be theoretically determined, and greatly improves characteristics by adding a first-order lag filter to resonance ratio control. It is an object of the present invention to provide a two-inertial-resonance-system vibration suppression device with improved resonance ratio control.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, a first aspect of the present invention is to amplify a two-inertia resonance system and a deviation output between an angular velocity command of a motor and an angular velocity of the two-inertial resonance system. a speed amplifier which, the output of the speed amplifier is supplied, a compensation filter that having a filter time constant T _F shown in (33), and a gain section that the output of the compensation filter is supplied, and the gain section A first deviation unit for transmitting a deviation from a resonance ratio gain unit as a torque command for the two inertial resonance system, and a second deviation for obtaining a deviation between the torque command from the first deviation unit and the differential element output of the angular velocity of the motor. Vessel and this second
An output of the deviator is supplied, and a 1 / (1 + sT) first-order lag filter for supplying an estimated shaft torque value obtained as an output to the resonance ratio gain section is provided. T _F <T <1 / ωm ωm: resonance frequency, T: observer time constant

According to a second aspect of the present invention, there is provided a two-inertia resonance system, a speed amplifier for amplifying a deviation output between the angular velocity command of the motor and the angular velocity of the two-inertial resonance system, a gain unit to which the output of the speed amplifier is supplied, A first deviator for obtaining a deviation between the gain unit and the resonance ratio gain unit; a deviation output of the first deviator supplied; a torque command transmitted to the output;
A compensation filter that having a filter time constant T _F, and a second deviation unit for taking the difference between the differential element output torque command and the motor angular velocity obtained from the compensation filter, the output of the second difference circuit is fed , And supplies an estimated shaft torque value obtained as an output to the resonance ratio gain section ｛(1 + sT _F ) / (1 + s)
T) A first-order lag filter. T _F <T <1 / ωm ωm: resonance frequency, T: observer time constant

According to a third aspect of the present invention, there is provided a two inertial resonance system, a speed amplifier for amplifying a deviation output between an angular velocity command of the motor and an angular velocity of the two inertial resonance system, and an output of the speed amplifier .
(33) a compensation filter that having a filter time constant T _F in the expression, a gain section which output is supplied for this compensation filter, adding to the two inertial output of the gain section and the resonance ratio gain section An adder that supplies a torque command to the resonance system and a shaft torque observer that is connected in parallel to the two-mass inertial resonance system and supplies an estimated shaft torque value obtained as an output to the resonance ratio gain unit. . T _F <T <1 / ωm ωm: resonance frequency, T: observer time constant

A fourth invention is characterized in that the shaft torque observer is constituted by a first-order lag observer.

A fifth invention is characterized in that a disturbance suppressing section is provided between the speed amplifier and the compensation filter.

[0010]

According to the first and second aspects of the present invention, vibration is suppressed by providing a compensation filter and a first-order lag filter, and in the third and fourth aspects, vibration is suppressed by a compensation filter and an axial torque observer or a first-order lag observer. I do.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following, one embodiment of the present invention will be described with reference to the drawings. First, a two-inertia system model and a resonance frequency will be described. The two-inertia model can be represented as 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 and ω _L are the angular velocities of the motor and load, T _M and _TL are the mechanical time constants of the motor, T _S
Is the spring time constant of the shaft. Since FIG. 1 is difficult to analyze, FIG. 1 is modified as shown in FIG. 2 to facilitate analysis. However, in this case, since the target is only the vibration suppression, the disturbance is excluded. In FIG. 2, G _M (S), G
ω (S) is a transfer function, and these functions are described in (2)
It is given by equation (3). First, a transfer function G _M (S) from τ _M to ω _M is obtained.

[0012]

(Equation 1)

From the above equation (1), the following equation (2) is obtained.

[0014]

(Equation 2)

Similarly, the transfer function Gω (S) is given by the following equation (3).

[0016]

[Equation 3]

[0017] for two-inertia system of FIG. 1, the resonance frequency omega _m and the antiresonant frequency omega _a when performing a resonance ratio control and low inertia control follows (4) and (5).

[0018]

(Equation 4)

[0019] In (4), typically K can as ^{R 2 = 5, K = T} M (R 2 -1) / T L = 4T M / T L ......... (6). At this time, the frequency characteristics from τ _M to ω _M are as shown in FIG.

Next, FIG. 4 shows the shaft torque observer. FIG. 4 can be modified as shown in FIG. From FIG. 5, the shaft torque is estimated through the first-order lag, whereby the detection noise and the like can be reduced. The relationship between the variables in FIGS. 4 and 5 is expressed by the following equation (7).

T = T _M * / K _LS (7) If the observer gain K _{LS in the} equation (7) is increased, it becomes possible to estimate up to higher frequencies, and the vibration suppression ability is increased. However, as described above, if the gain is increased, detection noise is also picked up, so that there is a problem that the gain cannot be increased very much. For this reason, the observer gain must be determined in consideration of two points, vibration suppression and disturbance suppression. Here, the minimum value of the observer gain is shown. In order to suppress vibration as shown in FIG. 6, the following equation must be satisfied.

1 / T> ω _m (8) From the equations (4), (6) and (7), K of the following equation (9) is obtained.
_LS must be selected.

[0023]

(Equation 5)

The following block diagrams of FIGS. 7 to 9 show:
In FIG. 7, reference numeral 11 denotes a compensation filter for enhancing the vibration suppression effect, 12 denotes a low inertia gain section, 13 denotes a shaft torque observer, and 14 denotes two inertia control compared with the embodiment of the present invention. System. 13a is a first-order lag filter, and ∧τ _S is an estimated shaft torque value.

FIG. 8 is a modified block diagram of FIG. 7. It can be seen from FIG. 8 that the shaft torque is estimated through the first-order lag filter 13a. The compensation filter 11
Has also been transformed.

FIG. 9 is a block diagram obtained by further modifying FIG. 8 and shows that two filters A and B are added. The vibration suppression effect of the compensation filter will be described below using these two filters A and B.

Next, considering the characteristics of the two filters A and B shown in FIG. 9, how to determine the characteristic values will be considered.

(1) Filter A This filter A is a filter for the torque command τ _M to the motor, and basically must pass all signals. Further, from the viewpoint of vibration suppression, the filter must pass the resonance frequency. Thus, the following expression (13) should be obtained from the expression (8). T
_F is a filter time constant.

T _F <T <1 / ω _m (13) (2) Filter B As shown in FIG. 8, the shaft torque is estimated through a first-order lag filter, thereby removing disturbance at the time of speed detection. I have. Therefore, the observer time constant T cannot generally be small. However, if the time constant T is large,
Even the resonance frequency is cut, making it impossible to suppress vibration. Filter B solves these problems. By setting the time constant T _F of the filter B as in the following equation (14), the influence of the observer time constant T can be canceled.

T _F ≒ T (14) In general, since K> 1, the characteristics of the filter B can be improved. From the above, the filter time constant TF should be designed so as to satisfy the equations (13) and (14). In other words, the filter A, the B must filter such as through the resonance frequency omega _m.

[0031] Here, description will be given of a case where obtaining a filter A, B, such as through the resonance frequency omega _m. The filter A can be expressed by the following equation (15), and the gain is expressed by the following equation (16).

[0032]

(Equation 6)

Similarly, the filter B can be expressed as follows. Here, if the gain is obtained from the following equation (17), the equation becomes complicated. Therefore, it is assumed that K is sufficiently large, and the gain is obtained as in equation (18).

[0034]

(Equation 7)

Now, when ω = ω _m , (16), (1)
Since it is sufficient that the gain in the expression 9) takes a larger value, the following can be performed. When both sides are differentiated by the time constant T _F from the equation (16), the equation (20) is obtained from K> 1. Therefore, equation (16) is a monotonically increasing function.

[0036]

(Equation 8)

In the same manner, from equation (19), equation (13)
The following equation (21) is obtained from the equation, and the equation (19) is a monotonically decreasing function.

[0038]

(Equation 9)

Therefore, when ω = ω _m (16), (1)
In order for the gain of the expression (9) to take a larger value, the following expression (22) should be satisfied. FIG. 10 shows conditions for passing the resonance frequency.

[0040]

(Equation 10)

Therefore, from T _F > 0, T _F is expressed by the following equation.

[0042]

(Equation 11)

FIGS. 11A to 11C show the characteristics of the filters A and B depending on the change of the time constant _TF . ω _m
If <1 / T, resonance ratio control may be used to suppress vibration. However, if ω _m > 1 / T, the vibration cannot be suppressed as shown in FIG. However, as shown in FIGS. 11 (b) and 11 (c), it is suppressed when it is in the characteristic improvement band. Also, like that T
Set _F. Further, in the inertia reduction control, a frequency of 1 / T or more can be passed when the time constant _TF is set (FIG. 11B). As a result, even when the observer gain cannot be increased, the time constant T _{F is set} to (2
The characteristics can be improved by using equation (6).

FIGS. 12 and 13 show the results of a simulation of a vibration suppression device of a two-inertia resonance system using the filter obtained as described above. Table 1 shows the constants used in this simulation.

[0045]

[Table 1]

12 and 13, a characteristic curve a is obtained by using the time constant T _F obtained by the equation (26), and a characteristic curve b is obtained by obtaining an optimum T _F from the root locus and performing a simulation. It is. The following table shows these time constants T
_Shows the value of _F.

[0047]

[Table 2]

From FIG. 12, K is a sufficiently large value (K = 1).
At the time of 6), the characteristic curves a and b are almost the same. However, as shown in FIG. 13, K is not so large (K = 4)
When it is, it is more vibrating. This is (1
This is because the assumption that K at the time of going from the equation (7) to the equation (18) is sufficiently large does not hold. Conversely, when K is sufficiently large, the time constant T _F can be calculated by equation (26).

Next, a first embodiment of the present invention will be described with reference to FIG. From the simulation results described above, it was found that Equation (26) could not be applied depending on the magnitude of K.
This corresponds to (1 + ST _F /
This is because the term K) has a great effect.
This term does not play any role in improving the characteristics and may be omitted. Therefore, the configuration of the resonance ratio control + first-order lag filter shown in FIG. 14 is modified from the low inertia control of FIG. In FIG. 14, the deviation between the angular velocity command ω _M * of the motor and the angular velocity ω _{M of the} motor is input to the speed amplifier 21.
The input torque τ _i obtained at the output is supplied to a first-order lag filter 22 which is a compensation filter. The output of the first-order lag filter 22 is supplied to a first deviation unit 24 via a gain unit 23.
Given at the plus end of the

The output from the resonance ratio gain section 25 is applied to the minus end of the first deviation device 24. A motor torque command τ _M is obtained as a deviation output of the first deviation unit 24. This motor torque command is input to the plus end of the two inertia system 26 and the second deviation device 27. The angular velocity ω _M of the motor obtained at the output of the two inertia system 26 is given to the minus end of the second deviator 27 via the differential element 28 of the inertia moment of the observer. The deviation output of the second deviation device 27 is a primary delay filter 29
To obtain an estimated shaft torque value ∧τ _S at the output thereof.
This estimated shaft torque value is supplied to the resonance ratio gain section 25.

With the above configuration, the first-order lag filters 22 and 29 do not include the term (1 + ST _F / K), so that filter characteristics independent of the inertia ratio K can be obtained. The speed amplifier 2 of the first embodiment
Although not shown, a disturbance suppressor may be provided between the first and first-order lag filters 22. The provision of the disturbance suppression unit enhances resistance to disturbance.

Next, a second embodiment will be described with reference to FIG.
The second embodiment is a modification of the first embodiment of FIG. 14, and the same parts as those of FIG. 14 are denoted by the same reference numerals. In FIG. 15, a first-order lag filter 30 is provided between the first deviation unit 24 and the second inertia system 26, and a first-order lag filter 31 provided between the second deviation unit 27 and the resonance ratio gain unit 25 will be described later. Is configured. Filters 30 and 31 used in the second embodiment are also (1 + ST _F /
Since the term K) is not included, a filter characteristic that is not affected by the inertia ratio K can be obtained.

Here, the filter 3 used in the second embodiment
The design means of 0 and 31 will be described. The filter 30 has the following (2)
The gain is obtained from equation (7), and the gain is expressed as equation (28).

[0054]

(Equation 12)

Similarly, the filter 31 is given by the following equation (29):
It is obtained from equation (30).

[0056]

(Equation 13)

Now, the value of the time constant T _F when ω = ω _m is obtained as follows.

[0058]

[Equation 14]

A simulation was performed using the above equation (33) in the same manner as described above. Table 3 shows the values of the time constant T _F used.

[0060]

[Table 3]

However, since the control systems are different, Tables 2 and 3
Cannot be directly compared. 16 and 17 show simulation results. The characteristic curves a and b shown in FIGS. 16 and 17 are the same as those in FIGS. 12 and 13, and the characteristic curve c is the result of the simulation of the resonance ratio control + first order lag filter in the embodiment of the present invention. In FIG. 16, the characteristics hardly change with the characteristic curves a, b, and c, but in FIG. 17, the characteristic curve c shows a somewhat poor characteristic. This is because of the relationship between the filters A and B described above. Filters A and B and filters 30 and 31
Are different from FIG. 8 and FIG. 15 (15), (17), (2)
7) and (29). Although the characteristics of the filters A and B are shown in FIG. 11, changes in the characteristics of both filters will be examined from another viewpoint. FIG. 18 shows (15),
It is a whole Bode diagram of Formula (17). Also, (2
The Bode diagrams of equations 7) and (29) are as shown in FIG.

Looking at the filter A and the filter 30, the characteristics of the filter A after ω = K / _TF are different from those of the filter 30, and the characteristics at ω ₁ are different as shown in FIG. . As for the filter A and the filter 30, the filter A shows better characteristics. Conversely, regarding filter B and filter 31, filter 31
Shows better characteristics. FIG. 21 shows the result of simulation to see these differences. The simulation constants are the same as in FIGS.

[0063] While towards low inertia control exhibits a good response by a decrease in K _LS by 21, this is because,
This is because the importance of the filter A and the filter B is different. That is, the filter A must pass all commands to the motor including the signal passed through the filter B. Therefore, the filter A should be considered more important than the filter B, and the filter A has better characteristics than the filter 30 as described above. Become.

The characteristic improvement first-order lag filter of the resonance ratio control of the above embodiment can be applied to the resonance ratio control of the third embodiment shown in FIG. 22 and the fourth embodiment shown in FIG. FIG.
In the third embodiment of FIG. 2, the shaft torque observer 41 is composed of an integral element 41a of a motor mechanical time constant and an observer gain 41b, and the fourth embodiment of FIG. 23 uses the primary torque used in the low inertia control shown in FIG. It consists of a delay observer. In FIGS. 22 and 23, reference numeral 42 denotes an adding unit.

[0065]

As described above, according to the present invention,
Two filters having vibration suppression capability are obtained from the low inertia control, and the resonance frequency of these two filters is combined to determine the time constant of the compensation filter to obtain the resonance ratio control and the first-order lag filter. There is an advantage that the suppression effect can be obtained and the configuration can be simplified.

[Brief description of the drawings]

FIG. 1 is a block diagram of a two-inertia model.

FIG. 2 is a block diagram showing a modification of the model of FIG. 1;

FIG. 3 is a frequency characteristic diagram of a two inertial system.

FIG. 4 is a block diagram showing a shaft torque observer.

FIG. 5 is a block diagram of an observer in which the shaft torque observer of FIG. 4 is modified and represented by a first-order lag system.

FIG. 6 is a characteristic diagram showing a relationship between an observer gain and a resonance frequency.

FIG. 7 is a block diagram showing inertia reduction control.

FIG. 8 is a block diagram showing a modification of the low inertia control.

FIG. 9 is a block diagram showing a modification of FIG. 8;

FIG. 10 is a characteristic diagram showing conditions for passing a resonance frequency.

FIG. 11 is a characteristic diagram of a filter due to a change in a time constant T _F of the filter.

FIG. 12 is a characteristic diagram based on a simulation result.

FIG. 13 is a characteristic diagram based on a simulation result.

FIG. 14 is a block diagram showing a first embodiment of the present invention.

FIG. 15 is a block diagram showing a second embodiment of the present invention.

FIG. 16 is a characteristic diagram of a simulation result according to the embodiment.

FIG. 17 is a characteristic diagram of a simulation result according to the embodiment.

FIG. 18 is a Bode diagram of filters A and B.

FIG. 19 is a Bode diagram of the filters 30 and 31.

FIG. 20 is a comparison characteristic diagram of the filter A and the filter 30.

FIG. 21 is a characteristic diagram showing a simulation result when the observer gain K _LS is changed.

FIG. 22 is a block diagram showing a third embodiment of the present invention.

FIG. 23 is a block diagram showing a fourth embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 21 speed amplifier 22, 30 first-order lag filter as compensation filter 23 gain unit 24 first deviation unit 25 resonance ratio gain unit 26 two inertial resonance system 27 second deviation unit 28 differential element unit 29 31 ... First-order lag filter

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G05B 11/00-13/04 H02P 5/00, 7/00

Claims (5)

(57) [Claims] And 1. A two-inertia resonant system, and the speed amplifier for amplifying the differential output of the angular velocity command and the 2-mass resonant system of the angular velocity of the motor, the output of the speed amplifier is supplied, shown in the following formula
A compensation filter that having a filter time constant T _F, a gain section which output is supplied for this compensation filter, first sends the deviation between the gain section and the resonance ratio gain section as the torque command of the 2-mass resonant system A first deviator, a second deviator for obtaining a deviation between a torque command from the first deviator and a differential element output of the angular velocity of the motor, and an output of the second deviator supplied to obtain an output shaft torque A two-inertial-resonance-system vibration suppression device based on resonance ratio control, including a 1 / (1 + sT) first-order lag filter that supplies an estimated value to the resonance ratio gain unit. T _F <T <1 / ωm ωm: resonance frequency, T: observer time constant 2. A two-inertia resonance system, a speed amplifier for amplifying a deviation output between an angular velocity command of the motor and an angular velocity of the two-inertial resonance system, a gain unit to which an output of the speed amplifier is supplied,
A first deviation unit for taking the difference between the gain section and the resonance ratio gain section, the differential output of the first deviation unit is supplied, and sends a torque command to the output, the filter time constant T _F of the following formula
A compensation filter that Yusuke, a second deviation unit for taking the difference between the differential element output torque command and the motor angular velocity obtained from the compensation filter, the output of the second difference circuit is fed,
Supplying shaft torque estimated value obtained at the output to the resonance ratio gain section _{{(1 + sT F) /} (1 + sT)} 2 mass resonant system vibration suppression apparatus according to the resonance ratio control comprising a first order lag filter. T _F <T <1 / ωm ωm: resonance frequency, T: observer time constant 3. A two-inertia resonant system, and the speed amplifier for amplifying the differential output of the angular velocity command and the 2-mass resonant system of the angular velocity of the motor, the output of the speed amplifier is supplied, shown in the following formula
A compensation filter that having a filter time constant T _F, a gain unit for the output of the compensation filter is supplied, as the torque command to the gain section and the two-inertia resonance system by adding the output of the resonance ratio gain section And a shaft torque observer connected in parallel to the two-mass resonance system and supplying an estimated shaft torque obtained at the output to the resonance ratio gain unit. Vibration suppression device. T _F <T <1 / ωm ωm: resonance frequency, T: observer time constant 4. An apparatus according to claim 3, wherein said shaft torque observer is constituted by a first-order lag-system observer. 5. The apparatus according to claim 1, further comprising a disturbance suppressor provided between the speed amplifier and the compensation filter.
5. The vibration suppression device of the two inertial resonance system according to claim 4.