WO1997003386A1

WO1997003386A1 - Vibration damping device

Info

Publication number: WO1997003386A1
Application number: PCT/JP1996/001876
Authority: WO
Inventors: Shinji Mitsuta; Kazuhiro Hatake; Hideaki Kawakami; Eishin Masutani
Original assignee: Komatsu Ltd.
Priority date: 1995-07-07
Filing date: 1996-07-05
Publication date: 1997-01-30
Also published as: KR970006984A; JPH0922304A

Abstract

A controlled system is preset as a controlled model having mechanical looseness between an actuator and a movable section. The value of a frequency weight function by which the sensitivity function expressing the target position follow-up ability of the movable section is multiplied is so determined that the value of the frequency weight function corresponding to the frequency region lower than a prescribed frequency is larger than the value of the fequency weight function corresponding to the other frequency region. The value of a frequency weight function by which the sensitivity function expressing the vibration damping ability of the controlled system is multiplied is so determined that the value of the frequency weight function corresponding to the resonance frequency of the controlled system is larger than the value of the frequency weight function corresponding to the other frequency region. The value of a frequency weight function by which an evaluation function (represented by a complementary sensitivity function) for evaluation the robust stability of the mechanical looseness of the controlled model is multiplied is so determined that the value of the frequency weight function corresponding to the frequency region higher than a prescribed frequency is larger than that corresponding to the other frequency region. Thus, the controller is improved in target position follow-up ability and vibration damping ability for a controlled system having mechanical looseness.

Description

Description Name of Invention

Vibration suppression device Technical field

The present invention relates to the control of a movement system for moving a structure including a vibration system, and by controlling the movement system, simultaneously reduces vibrations generated in the vibration system. The present invention relates to a vibration suppressing device which enables positioning, and more particularly to a device which is suitably applied to reduce the vibration of a feed bar of a transfer press. Background art

Figure 1 shows the configuration of the transfer control device of the transfer press, that is, the control device of the feed bar.

As shown in FIG. 1, the press angle of the press machine is detected by a press angle detecting encoder 1, and a signal indicating the press angle 2 is input to a trajectory table section 3. The trajectory table section 3 outputs a signal indicating the position command 4 corresponding to the press angle 2 to the position control circuit section 7 based on the input signal 2 and the target trajectory of the feedback shaft 19.

The position control circuit unit 7 outputs a signal indicating the speed command 9 to the speed control circuit unit 11 based on the position command 4 input from the trajectory table unit 3.

The speed control circuit section 11 outputs a motor drive command to the servomotor 15 based on the speed command 9 input from the position control circuit section 7.

The servomotor 15 drives the feedback mechanism 19 via a drive mechanism 18 (for example, a rack and pinion mechanism) in response to a motor drive command input from the speed control circuit section 11.

At this time, the speed control circuit section 11 outputs a motor drive command based on the speed feedback amount 13 detected by the tacho generator 16 attached to the motor 15. You.

Further, the speed feedforward section 5 calculates a feedforward control amount 6 of the speed based on the position command 4 output from the trajectory table section 3 and adds this to the position control circuit section 7. The position feedback amount 14 detected by the encoder 17 attached to the motor 15 is applied to the position control circuit unit 7.

The position control circuit 7 generates and outputs a speed command 9 based on the speed feedforward amount 6 and the position feedback amount 14.

As described above, the feed bar 19 of the transfer press is driven by the feed pack control or the feed head control, so that the feeder 19 can accurately follow the target trajectory. It is.

However, it has been extremely difficult to suppress the vibration of the central portion that occurs when the feeder 19 is positioned at a predetermined position.

In other words, in the transfer press, the work is sequentially conveyed to the mold in the next process by the feed bar, but when trying to position the work in the mold in the next process, the feed bar holding the workpiece vibrates. Would. As a result, a work positioning error is likely to occur. In addition, as the production speed (transport speed) increases, the vibrations increase, so that the production speed cannot be increased beyond a certain level, which limits the production efficiency.

However, in the semi-closed loop control system shown in Fig. 1, if the speed feedback amount 13 is a full closed loop control system that takes the direct feedback from the feed bar 19, the vibration of the mechanical system can be suppressed to some extent.

However, in this case, the mechanical system is included in the speed feed-up loop, and the characteristics of the mechanical system, particularly mechanical play (for example, the gap between the rack and the pinion), may adversely affect the speed loop. . As a result, even when there is no speed difference between the motor 15 and the feed bar 19, that is, even in a situation where vibration is not originally generated, the speed loop is not performed due to the feed-back of the mechanical characteristics described above. As a result, when the feed bar 19 is moving or positioned, the vibration is likely to occur.

Therefore, without impairing the target position tracking capability of the feed bar 19, the load The control gain is increased in the low frequency range to suppress fluctuations, and the control gain is increased in the high frequency range to reduce the effects of relatively high frequency sensor noise superimposed on the position loop loop. Here, a method of trading off sensitivity characteristics and robust stability using H∞ control theory is described in, for example, Japanese Patent Laid-Open No. The technology is disclosed in the official gazette.

As is well known, H∞ control theory uses frequency weights to be multiplied by an evaluation function that evaluates robust stability, such as the sensitivity function and complementary sensitivity function of the controlled object, so that the H∞ norm of the controlled object is equal to or less than a predetermined value. The theory is that the function value of the function is determined, and the frequency characteristics (frequency transfer function) of the controller are determined accordingly.

However, although the technology disclosed in the above-mentioned publication does not aim to improve sensitivity characteristics showing quick response and follow-up characteristics and mouth bust stability against shaft torsional vibration, control parameter fluctuation, etc. It is difficult to prevent vibrations occurring in the controlled object itself or torsional vibrations of the shaft, and such vibrations often hinder high-speed, high-precision control of the controlled object:

In particular, when applied to the transport control of the feed bar 19, the part of how to set the control gain to guarantee the stability of the entire feed bar 19 was left to intuition and experience, It is extremely difficult to prevent the vibration generated in the feedback bar 19 itself or the torsional vibration of the motor shaft.

Other conventional methods for reducing vibration include the following methods.

1) Use a lightweight, high-rigidity material for the feedback bar 19 to reduce vibration.

2) Vibration is reduced by installing a dynamic vibration absorber such as a cylinder on the feeder 19.

However, these methods 1) and 2) have the following problems. First, the method 1) of using lightweight and high-rigidity materials generally increases the cost of the materials and raises problems such as workability and durability. In addition, when such a material is used, the amplitude of the vibration is reduced, but the attenuation of the residual vibration is still improved. Will not be up.

In addition, in the method of 2) where a dynamic vibration absorber is mounted, tuning is necessary according to the resonance frequency. Also, in order to apply to the existing equipment, the existing equipment itself needs to be greatly remodeled, resulting in high cost. Disclosure of the invention

The present invention has been made to solve these problems, and is intended to achieve a vibration generated in a controlled object having a mechanical play such as a feeder without impairing the target position tracking performance. The objective is to realize high-speed, high-precision control of the controlled object and to easily configure the control device without using expensive materials or modifying existing devices. It is assumed that. The purpose of the present invention is

A movable part positioned at a target position, an actuator for driving the movable part, and a drive command signal for positioning the movable part at the target position based on a signal indicating the target position, A sensitivity function and a port of the controlled object based on H H control theory such that the H∞ norm of the controlled object including the movable part and the actuator is less than or equal to a predetermined value. By determining a function value of a frequency weighting function to be multiplied by an evaluation function for evaluating bust stability, a vibration suppression device configured to determine a frequency characteristic of the controller is provided. Is set in advance as a control model with mechanical play between the

Regarding the function value of the frequency weighting function to be multiplied by the sensitivity function indicating the target position tracking performance of the movable section, the function value corresponding to a low frequency range below a predetermined frequency is larger than the function value corresponding to another frequency range. Decide to be, force, one,

Regarding the function value of the frequency weighting function to be multiplied by the sensitivity function indicating the vibration suppression performance of the controlled object, the function value corresponding to the resonance frequency of the controlled object is larger than the function values corresponding to other frequency ranges. To decide on, and

The function value of the frequency weighting function to be multiplied by the evaluation function for evaluating the mouth bust stability of the control model with respect to the mechanical play, Determine that the corresponding function value is larger than the function values corresponding to other frequency ranges

Achieved by:

Here, the sensitivity function indicating the target position following performance of the movable part is, specifically, a transfer function using the target position as an input signal and the deviation between the current position of the movable part and the target position as an output signal. is there.

Further, the sensitivity function indicating the vibration suppression performance of the controlled object is, specifically, a transfer function that uses a disturbance applied to the controlled object as an input signal and the amount of vibration of the controlled object as an output signal. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a diagram showing a configuration of a conventional device.

FIG. 2 is a diagram illustrating a configuration of the apparatus according to the embodiment.

FIG. 3 is a diagram showing a configuration of the apparatus according to the embodiment.

FIG. 4 is a diagram showing the configuration of the apparatus according to the embodiment.

FIG. 5 is a perspective view showing the appearance of the transfer press.

FIG. 6 is a diagram for explaining the operation of the feed bar.

Fig. 7 is a control model diagram of the control target.

Fig. 8 is a control block diagram considering the uncertainty of the actual control target.

FIGS. 9 (a), 9 (b), 9 (c), 9 (d), and 9 (e) show the frequency characteristics of the frequency weight function.

FIG. 10 is a diagram illustrating the basic structure of two-degree-of-freedom control.

FIG. 11 is a diagram for explaining a case where two-degree-of-freedom control is applied to the embodiment device.

Figure 12 is a control block diagram that takes into account the uncertainty of the actual control target.

FIGS. 13 (a), 13 (b), and 13 (c) are diagrams showing frequency characteristics of the frequency weighting function.

FIGS. 14 (a), 14 (b), 14 (c), 14 (d), and 14 (e) are diagrams showing the frequency characteristics of the filters of the two-degree-of-freedom control law parameters.

FIG. 15 is a diagram showing a time change of the vibration displacement of the feed bar. Fig. 16 is a diagram showing the time change of the vibration displacement of the feeder.

FIG. 17 is a diagram showing the time change of the vibration displacement of the feed bar. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of a vibration suppression device according to the present invention will be described with reference to the drawings.

In this embodiment, as shown in FIG. 5, when the present invention is applied to the suppression of the vibration generated in the feed bar 19 which conveys the work in the direction of the arrow between the transfer presses 100 and 200, as shown in FIG. Is assumed.

FIG. 6 is a diagram for explaining the operation of the feeder 19.

That is, the feeder 19 is composed of two bars and fingers for gripping the work (see FIG. 5). The feeder 19 holds the work (clamp) and lifts it to a position where it does not interfere with the mold (lift-up). ), Unloading and positioning to the next die station (advance), setting the work in the die (lift down), releasing the work and moving the feed bar to a position where the upper die does not interfere with the fingers. The operation of retracting (unclamping) and the operation of returning to the home position (return) in order to transport the work in the next processing cycle are sequentially and repeatedly performed.

FIGS. 2, 3, and 4 are block diagrams showing the devices of the respective embodiments, and the same reference numerals are given to components having the same functions as those of the conventional device of FIG.

That is, as shown in these figures, the angle of the press crankshaft of the press machine is detected by the press angle detection encoder 1, and a signal indicating the press angle 2 is input to the locus table unit 3. The trajectory table section 3 generates a signal indicating a position command 4 (on the target trajectory) corresponding to the press angle 2 based on the input signal 2 and the target trajectory of the feed bar 19 stored in advance. Either output to the position control circuit unit 7 (in the case of FIGS. 2 and 4) or output to the H∞ controller 8 (in the case of FIG. 3).

The position control circuit unit 7 in FIGS. 2 and 4 outputs a signal indicating a speed command 9 to the H∞ controller 8 based on the position command 4 input from the trajectory table unit 3.

The speed control circuit section 11, which is a servo amplifier, generates a motor drive command based on the speed command 10 calculated and output by the H∞ controller 8, and outputs this to the servomotor 15. You.

The servomotor 15 drives the feed bar 19 via a drive mechanism 18 (for example, a rack-pinion mechanism) in response to a motor drive command input from the speed control circuit section 11.

At this time, the speed control circuit section 11 outputs a motor drive command based on the speed feed pack amount 13 detected by the tacho generator 16 attached to the motor 15.

The speed feedforward section 5 shown in FIGS. 2 and 4 calculates a feedforward control amount 6 of the speed based on the position command 4 output from the trajectory table section 3, and converts this into a position control circuit section 7. Add to Further, the position feedback amount 14 detected by the encoder 17 attached to the motor 15 is applied to the position control circuit section 7 (in the case of FIGS. 2 and 4).

Therefore, the position control circuit unit 7 shown in FIGS. 2 and 4 generates and outputs the speed command 9 based on the speed feedforward amount 6 and the position feedback amount 14. In the case of FIG. 3, the position feedback amount 14 is added to the H∞ controller 8.

In the apparatus shown in FIG. 4, a vibration detector 20 for detecting the vibration generated at the feeder 19 is attached to the feed bar 19, and the vibration signal 21 detected by the vibration detector 20 is H. ∞ Output to controller 8.

The H∞ controller 8 is a controller designed based on the H∞ control theory, and calculates a speed command 10 that minimizes the vibration acceleration of the feeder 19.

The input signal of the H∞ controller 8 is one or more of the following signals (1) to (3).

(1) Signal 9 indicating the deviation between the target position 4 of the feed bar 19 output from the trajectory table section 3 and the actual movement position 14 of the feed bar 19

(2) A signal indicating the target position 4 of the feed bar 19 output from the trajectory table section 3 and a signal indicating the actual movement position 14 of the feeder 19

(3) Vibration signal of feed bar 1 9 2 1

That is, in the device of FIG. 2, the input signal of the H∞ controller 8 is the input signal 9 shown in the above (1), and in the device of FIG. 3, the input signal of the H∞ controller 8 is the above The input signals 4 and 14 shown in (2) are shown. In the apparatus shown in FIG. 4, the input signals of the H∞ controller 8 are the input signals 9 and 21 shown in the above (1) and (3). Has become. When the feed bar 19, which is a movable part, is accelerated or decelerated by the rotational force of the motor 15, the feeder 19 is deformed by the inertial force acting on the feeder 19. Since the restoring force acts on the feed bar 19 at the same time according to the amount of deformation, vibration is generated particularly at the time of positioning to the next process position (at the time of completion of transport to the next process).

The movement and positioning of the feed bar 19 are generally controlled by the position control circuit 7 as feedback control, as shown in FIG. That is, the position control circuit 7 calculates the deviation between the target position 4 of the feed bar 19 and the current position 14 and multiplies the deviation by an appropriate coefficient to obtain a low-pass filter as necessary. The signal is output to the speed control circuit 11 through the evening.

In the embodiment apparatus shown in FIGS. 2 and 4 according to the present invention, an H∞ controller 8 is further inserted between the position control section 7 and the speed control circuit section 11, and the H さらに controller 8 shown in FIG. In the apparatus, a vibration detector 20 for detecting the vibration displacement (vibration amount) of the feeder 19 is mounted on the feed bar 19.

By adding such a device, the output 21 of the vibration detector 20 is taken into the H∞ controller 8, and an appropriate control operation for damping the vibration of the feed bar 19 is performed. As a result, The feed bar 19 can be moved so that vibration does not occur in the feed bar 19, and the vibration generated in the feed bar 19 due to external force or the like when the feed bar 19 stops can be quickly attenuated. Become like

In the control algorithm of the H∞ controller 8, two detectable amounts are the output 9 of the position control circuit unit 7 and the output 21 of the vibration detector 20 and are in the form of output feedback.

When the H∞ controller 8 is viewed from the viewpoint of vibration system control, the control in which the vibration amount 21 is fed back from the vibration detector 20 corresponds to the control for adding attenuation to the feed bar 19.

On the other hand, the velocity command signal 9, which is a position deviation signal input from the position control circuit unit 7 for positioning the feed bar 19, corresponds to a disturbance signal that causes vibration for a vibration system. The controller 8 feeds the disturbance signal This is to control the movement of the feedback bar 19 so as not to excite the vibration generated in the feedback bar 19 by the feed control.

Next, as one of the design methods of the control algorithm of the H∞ controller 8, a control method using a synthesis method will be described.

First, as shown in FIG. 7, three masses (mass) are connected to each other by a panel and a damper (damper) as shown in FIG. And make a linear model.

That is, the connection between the drive mechanism 18 between the motor 15 and the feeder 19, that is, for example, the connection by the rack and pinion mechanism is treated as the connection by the hard panel k2 and the damper c2, and an unknown external force fg is applied to this connection. Shall be added. In other words, the non-linearity due to mechanical play generated in the drive mechanism 18 is represented by the external force fg. Here, the equivalent mass of the motor 15 mm, the equivalent mass of the feedback 19 ml, m2, equivalent stiffness kl, k2, equivalent damping cl, c2 are measured transfer function and time response by a method such as impact excitation. The following equations (1), (2), and (3) are obtained when the equation of motion is established for the control model in Fig. 7.

m _m ⁺ ₂ ( ^X _m - ^X l) ^{+ C} 2 ( ^jC n,-^ l) ^{= Z} f _m -f _g (R m ₂ x ₂ -kx ^^-c ^ -x ₂ ) = f _d ( 3) Here, xm, xl, and x2 are the positions in the absolute coordinate system x of mass mm, ml, and m2, respectively, fd is the disturbance force acting on mass m2, and fm is the driving force of Each is represented.

Regarding the servo motor 15, the response of the drive torque to the input signal is regarded as a first-order lag system, the time constant is set, and the gain is a. Assuming that the error is a signal obtained by multiplying the error by the coefficient Kv, the following equation (4) holds for the driving force fm of the servo motor 15:

Summarizing the above equations (1) to (4), the following equation (5) is obtained: 0 0 1 -1 0 0 0

0 0 0 1 1 1 0 0

1

o o

One 0

m _m m

2k,

1 2 (, c.1 + c, 2) c. 1

0 0

X = ^m i ^m i

K _v

0 0 0 0

τ- 丄 τ.

0 0 1 0 0 0 0

Here, the matrix χ represents a state variable, and is defined by the following equation (6).

Z Factory ² x _m X x ₂ f _m x _m ] ^(ό)

Here, the information that can be directly detected and used by the H∞ controller 8 is the acceleration yl in the center of the feed bar 19 and the error y2 between the target trajectory 4 of the motor 15 and the actual trajectory 14, and The output equation for the control output y = [yl y2] is written as:

As a result, the state equation and the output equation are written as shown in equations (8) and (9) below. Stated ₃

x = Ax + Bu + Ew (8)

y = Cx + Du + Fw (9) At this time, the control target (plant) P is defined as in the following equation (10).

The frequency characteristic of the H∞ controller 8 may be determined based on the H∞ control theory based on the control model thus obtained.

That is, the following items are required for the H∞ controller 8

(a) Move the position of the feed bar 19 (motor 15), which is a movable part, to the command position-

(b) Damping the vibration generated in the feedback 19 quickly.

(c) Stable against dynamics such as higher-order modes not considered in the model

(Mouth bust stability).

Such a requirement can be considered as follows.

First, the requirement of (a) above is based on the fact that the motor 15 (feedback

This can be realized by minimizing the transfer function that uses the target position 4 of 19) as an input signal and the deviation between the actual position 14 and the target position 4 as an output signal.

The requirement (b) is realized by suppressing a transfer function that uses a disturbance fd that excites vibration as an input signal and a vibration amount 21 (x2-xl) as an output signal.

In addition, the requirement of (c) above treats the non-modeling mode of the controlled object in a relatively high frequency range as an additive error or a multiplicative error so that the bust is stable against these uncertainties. Is achieved by:

However, when designing a controller that is to be controlled and vibrated by one control signal u, the above requirements (a) to (c) are dependent on each other, and there is a trade-off. Do:

Of these, the above requirements (a) and (b) depend only on the parameters of the control model and are originally dependent on each other: Therefore, in the case of a controlled object whose motion and vibration are controlled by the motor 15 which is a single actuator, both are separated in the frequency domain so as to achieve a trade-off between the vibration suppression performance and the target position tracking performance. Think about it.

In addition, there is always a trade-off between control performance and mouth bust stability so that the complementary function becomes larger if the sensitivity function is made smaller, and the sensitivity function becomes larger if the complementary function becomes smaller. .

Therefore, in order to make these trade-offs, it is only necessary to consider both in the frequency domain.

Now, between the motor 15 and the feeder 19, there is a mechanical gas as described above. Therefore, in addition to the above (a), (b) and (c),

(d) The adverse effects of mechanical play are suppressed.

It becomes essential. Control should not be actively performed for this mechanical backlash. In other words, it can be considered as a problem of mouth bust stabilization that suppresses the sensitivity to the control input from the backlash disturbance.

Therefore, for the requirement (a), the function value of the frequency weighting function multiplied by the sensitivity function indicating the target position tracking performance is increased in the low frequency range, and for the requirement (b), the vibration control performance is increased. The function value of the frequency weighting function to be multiplied by the sensitivity function shown in the figure is increased in the resonance frequency range, and for requirement (c), an evaluation function such as a complementary sensitivity function for evaluating mouth bust stability against uncertainty of the controlled object The function value of the frequency weight function multiplied by the evaluation function for evaluating the robustness of the controlled object against mechanical backlash is increased by increasing the function value of the frequency weight function multiplied by By setting it to be large in the region, it would normally balance conflicting demands.

Note that only the requirements (a), (b), and (d) may be satisfied.

Hereinafter, an evaluation function such as a complementary sensitivity function that guarantees mouth bust stability against model uncertainty is called a maximum allowable uncertainty function.An evaluation function that guarantees robust stability against mechanical play is called a play uncertainty function. I will call it.

Taking these requirements (a) to (d) into consideration, consider this as a control problem for single synthesis. Then, as shown in Fig. 8, it has generalized plant and structural uncertainty It can be treated as a system stabilization problem.

In FIG. 8, Δ is any stable transfer function of magnitude less than one.

P represents a linear model of the controlled object, and is a transfer function expressed by the following equation (11).

(11)

The model parameters to be controlled are as shown in the table below:

Norame overnight value, ° Lame overnight value

800 kg 1.414x103 Ns / m mi 2000 kg 9.197x105 Ns / xn

300 kg 6.631x10-3 sk 5.476x105 N / m aK _v 1.508x105 Ns / m 2 1.022x109 N / m Wpf2 is the frequency weighting function that multiplies the sensitivity function that indicates Wad2, the frequency weight function that multiplies the play uncertainty function is Wrt:

Therefore, for the frequency weighting function Wpfl that determines the damping performance, the function value becomes maximum near the primary resonance frequency to be damped, and the function values of the other low and high frequency bands are the function values of the resonance frequency. Set to be smaller.

In addition, for the frequency weighting function Wpf2 that determines the target position tracking performance, the function value is set to be large in the low frequency range and small in other high frequency ranges:

In addition, the frequency function Wad that multiplies the maximum allowable uncertainty function and the play uncertainty function For 1, Wad2, and Wrt, the function value is set to be large in the high frequency range, and to be small in other low frequency ranges.

As a result, the frequency characteristics of these frequency weighting functions Wpfl, Wpf2, WadL Wad2, and Wrt are set as shown in Fig. 9 (a), (b), (c), (d), and (e), respectively. The frequency weighting functions Wpfl, Wpf2, WadU Wad2, and Wrt are expressed as in the following equations (12) to (16).

When the frequency weighting functions Wpfl, Wpf2, Wadl, Wad2, and Wrt are set as described above, the controller, that is, H The frequency characteristics of the controller 8 will be determined. Next, a description will be given of a design procedure when the embodiment apparatus shown in FIG. 3 is regarded as a two-degree-of-freedom control:

Figure 10 shows the basic structure of two-degree-of-freedom control, in which the control model of the servo feeder is P, the measured quantity of the feedback controller is y, the controlled quantity is z, and the transfer characteristic from r to z is improved. think of. The right irreducible decomposition of P is

^(N ,

P = D (17)

Let N be the transfer characteristic from r to z is N1T, and the feedback controller K does not affect N1T:

The configuration of the two-degree-of-freedom control + H∞ controller when applied to the device of this embodiment (Fig. 3) is shown in Fig. 11. The design procedure of this control system is as follows. (1) Design controllers K1 and K2 using H て control to improve the feedback characteristics.

(2) Design T so that the transfer characteristic N1T from r to z becomes desirable ₌

(3) Construct a controller using Kl, K2 and T.

As shown in FIG. 11, for the position feedback, a constant loop gain is applied in advance by multiplying the position deviation by a constant K2, and the H∞ control is applied to the acceleration feedback. For position feedback, for example, a constant K2 with a value as shown in (18) below can be used.

K ₂ = 50 (18) The acceleration feedback Kl is designed by the H∞ control theory using a generalized plant and a model of structural uncertainty as shown in Fig. 12.

Here, as in the case of Fig. 8, the function value of the frequency weighting function Wpfl that determines the damping performance is maximized near the primary resonance frequency to be damped, and the other low frequency band, Set so that the function value in the high frequency band is smaller than the function value in the resonance frequency:

For the frequency weighting function Wpf2, which determines the target position tracking performance, the function value is set to increase in the low frequency range and to decrease in other high frequency ranges.

For the frequency functions Wad1, Wad2, and Wrt that are multiplied by the maximum permissible uncertainty function and backlash uncertainty function, the function value is set to be large in the high frequency region and small in other low frequency regions. :

The frequency characteristics of each frequency weighting function Wpfl, Wpf2, Wadl are set as shown in FIGS. 13 (a), (b), and (c), respectively. In addition, these frequency weighting functions Wpfl, Wpf2, and Wadl are represented by the following equations (19) to (21). ·

The parameters T, D, N2 (acceleration feedback side), N2 (position feedback side) and K1 (acceleration feedback side) of the two-degree-of-freedom control law have the frequency characteristics shown in Figs. 14 (a) to (e). The two-degree-of-freedom control described above is described in, for example, the document “Control System Design-H∞ Control and Its Application” (edited by the Society of Systems Information Engineers, edited by Shigeyuki Hosoe and Mitsuhiko Araki / Asakura Shoten). This is a known technique as shown.

FIGS. 15 to 17 show how the vibration displacement changes with time when the feed bar 19 is positioned.

The production speed (feed bar speed) is shown for 15 SPM, 20 SPM, and 27 SPM, respectively:

Figure 15 shows the vibration displacement when the conventional control is performed, and it can be seen that the amplitude increases almost in proportion to the production speed:

FIG. 16 shows the vibration displacement when the H∞ control of this embodiment is performed, and it can be seen that the overall amplitude is smaller than that of the conventional control method shown in FIG. Fig. 17 shows the vibration displacement when H∞ control + two degrees of freedom control of the present embodiment was performed, and it was compared with the conventional case of Fig. 15 as well as with the case of this embodiment of Fig. 16. It can also be seen that almost no overshoot has occurred:

As described above, according to the present invention, the frequency region is divided into a low frequency region, a resonance frequency region, and a high frequency region, and the target position following performance, the vibration suppression performance, and the mechanical backlash of the controlled object are controlled. The bust stability is traded off.

This allows the control unit to be easily configured without using expensive materials or modifying existing equipment:

In addition, since the target position following performance and the vibration suppression performance can be simultaneously satisfied for a controlled object with mechanical backlash, vibrations may occur in the vibration system of the controlled object. It will be possible to immediately follow the motion command as soon as possible, realizing high-speed, high-precision control of the control target.

In particular, when applied to suppress the vibration of the feed bar, the vibration of the feed bar can be minimized, so that the positioning error does not occur during the transfer of the work. As a result, there is room for the production speed of the transfer press, and production efficiency can be dramatically improved. Industrial applicability

INDUSTRIAL APPLICABILITY The present invention is applicable not only to the suppression of the vibration of the feed bar of the transfer press, but also to the control of a motion system for moving a structure including a vibration system.

Claims

The scope of the claims

1. A movable section positioned at a target position, an actuator driving the movable section, and a drive command signal for positioning the movable section at the target position based on a signal indicating the target position, A controller for outputting to the actuator over time, and based on H∞ control theory, the sensitivity of the control object such that the H∞ norm relating to the control object including the movable part and the actuator over time becomes equal to or less than a predetermined value. In a vibration suppression device that determines a frequency characteristic of the controller by determining a function value of a frequency weighting function to be multiplied by an evaluation function for evaluating a function and mouth past stability,

The control target is set in advance as a control model having mechanical play between the actuary and the movable part,

Regarding the function value of the frequency weighting function to be multiplied by the sensitivity function indicating the target position tracking performance of the movable section, the function value corresponding to a low frequency range below a predetermined frequency is larger than the function value corresponding to another frequency range. Is determined to be, and

Regarding the function value of the frequency weight function to be multiplied by the evaluation function for evaluating the robust stability of the control model with respect to the mechanical play, the function value corresponding to a high frequency region equal to or higher than a predetermined frequency corresponds to another frequency region. Decided to be larger than the function value,

Vibration suppression device.

2. A movable part positioned at a target position, an actuation unit for driving the movable part, and a drive command signal for positioning the movable part at the target position based on a signal indicating the target position, A controller for outputting to the actuators, and based on the H の control theory, the sensitivity of the controlled object is controlled so that the H∞ norm of the controlled object including the movable part and the actuator is less than a predetermined value. Function and the function value of the frequency weight function to be multiplied by the evaluation function for evaluating mouth bust stability. By determining the frequency characteristics of the controller, the frequency characteristics of the controller are determined.

The control object is set in advance as a control model in which an uncertain element exists, and in which there is mechanical play between the actuator and the movable part,

Regarding the function value of the frequency weighting function to be multiplied by the sensitivity function indicating the vibration suppression performance of the controlled object, the function value corresponding to the resonance frequency of the controlled object is larger than the function values corresponding to other frequency ranges. To be determined, and

Regarding the function value of the frequency weighting function to be multiplied by the evaluation function for evaluating the mouth bust stability with respect to the uncertain element of the control model, the function value corresponding to a high frequency region equal to or higher than a predetermined frequency corresponds to another frequency region. Is determined to be larger than the function value

Regarding the function value of the frequency weighting function to be multiplied by the evaluation function for evaluating the mouth bust stability of the control model with respect to the mechanical play, the function value corresponding to a high frequency region equal to or higher than a predetermined frequency corresponds to another frequency region. To be larger than the function value

Vibration suppression device.

3. The sensitivity function indicating the target position tracking performance of the movable unit is a transfer function that uses the target position as an input signal and outputs a deviation between the current position of the movable unit and the target position as an output signal. Vibration suppressor according to range 1

4. The sensitivity function indicating the target position tracking performance of the movable unit is a transfer function that uses the target position as an input signal and outputs a deviation between the current position of the movable unit and the target position as an output signal. 3. The vibration suppressor according to claim 2, wherein

5. The sensitivity function indicating the vibration suppression performance of the controlled object is a transfer function that uses a disturbance applied to the controlled object as an input signal and uses the vibration amount of the controlled object as an output signal. Vibration suppression device.

6. The sensitivity function indicating the vibration suppression performance of the controlled object is determined by the function added to the controlled object. 3. The vibration suppression device according to claim 2, wherein the transfer function is a transfer function that uses a disturbance as an input signal and a vibration amount of the controlled object as an output signal.

7. The vibration suppressing device according to claim 1, wherein the movable portion is a feeder of a transfer press.

8. The vibration suppressing device according to claim 2, wherein the movable portion is a feed bar of a transfer press.