JPH01213703A - Active attenuation control method - Google Patents

Abstract

PURPOSE:To effectively attenuate oscillation by delaying the phase of the detection signal of an alternating power detecting means in a first-order integral means by 90 deg. and outputting the phase-delayed signal to a corresponding displacement generating means in each attenuation supporting means. CONSTITUTION:A band plate 2 which has a light emitting and receiving device 1 having mass (m) in the front end is fixed to a frame 4 through an attenuation supporting device 3 like a cantilever. The attenuation supporting device 3 consists of a piezoelectric actuator as the displacement generating means and an attenuation supporting body using an alternating power detector. When the frame 4 is oscillated, an oscillating force L acts upon the attenuation supporting device 3 and is detected and led to a controller 11. Alternating power detection signals Vf5-Vf7 are adjusted with respect to sensitivity by preamplifiers P1-P3 in the controller 11 and are given to control circuits C1-C3 and are inputted to first-order integrators 12-14 related to time, and applied voltage signals Va5-Va7 are given to the piezoelectric actuator through adders 15-17 or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an active damping control method, and more particularly, to a device for vibration isolating while supporting an object having complex vibration modes such as torsional vibration and bending vibration. The present invention relates to an active damping control method using.

[Prior art]

For example, in a robot arm that supports a lens or a light emitting/receiving device for positioning work, when a disturbance force such as an impact force is applied to the robot base, the lens or the light emitting/receiving device may vibrate. Such vibrations usually have a short duration (the vibrations will eventually stop, but during that time, positioning errors occur and the quality of the work deteriorates.Moreover, the arm supporting the object is Since there is a limit to the vibration damping ability depending on the structure, attempts have been made to actively dampen vibrations.

Conventional allocation means include, for example, attaching an acceleration detector to the tip of the robot arm, or detecting displacement or speed due to vibration, and controlling the motor for arm movement based on the detection signals obtained from these detection means. So-called active vibration isolation has been proposed. However, these conventional methods attempt to suppress vibration at the point where the detector is attached, and in a flexible robot arm where vibration has several modes, the detector is attached at the point and the motor is attached at the point. Control often becomes unstable due to the distance. Furthermore, the motor drive signal requires a large signal for moving the arm and a small signal for allocation to be superimposed, resulting in problems such as a complicated control device.

Originally, the vibration of an arm that supports an object, such as a robot arm,
In some cases, vibration occurs only in the supporting direction, but there are also vibrations in the direction perpendicular to the arm, torsional vibration, etc. Therefore, there is a need to provide a means for more effectively damping vibrations other than these dimensions. Similarly, effective allocation means is desired for fixed arms that do not necessarily move, such as robot arms.

[Problem to be solved by the invention]

The present invention has been made to solve the problems of the prior art as described above, and its purpose is to simultaneously control vibrations including linear, bending, and torsional vibrations using a simple control system. An object of the present invention is to provide a controllable active damping control method.

[Means to solve the problem]

To achieve the above object, the active damping control method of the present invention has a configuration in which a displacement generating means that expands and contracts and is displaced, and an alternating force detecting means that detects vibration propagating through the displacement generating means are arranged in series. A plurality of damping support means are used to support the object to be vibration-isolated, and the corresponding displacement generating means is based on a signal obtained by first-order integration with respect to time of the alternating force detection signal outputted by each of the alternating force detectors. It is characterized by controlling the displacement of.

The displacement generating means is not particularly limited as long as it has a structure with a large displacement resistance and can expand and contract with good response to input signals in the supporting direction, but it is usually a piezoelectric displacement generating means made of a stack of disc-shaped piezoelectric elements. Preferably, the means are used.

The alternating force detecting means is not particularly limited as long as it can be installed in series with the displacement generating means and used as part of the supporting means, but for example, it may be a piezoelectric load sensor, a strain gauge, or a disk type. For example, it is a stack of piezoelectric elements.

As means for first-order integration of the detection signal output from the alternating force detector, for example, an integrating circuit using an operational amplifier can be used, but the present invention is not limited thereto.

There are no particular limitations on the arrangement of the plurality of damping support means, and they may be arranged in parallel and have an integral structure for convenient handling, may be built into a support arm shape such as being incorporated into a robot arm, or may be a table. One anti-vibration support means is placed between each of the four legs provided on the floor and the floor,
The arrangement form can be selected as appropriate depending on the support form and vibration mode, such as supporting the object to be vibration-isolated by the floor and wall and interposing the damping support means at the support points.

[For production]

The means for independently integrating the signals detected by the plurality of alternating force detecting means for each damping support means on the first order with respect to time is a signal whose phase is delayed by 90 degrees from the detection signal of the alternating force detecting means. Vibration is effectively damped by simple control means in which phase and phase signals are output to each damping support means, that is, to each corresponding displacement generating means by independent control calculations.

[Example 1] Hereinafter, the method of the present invention will be specifically explained by way of an example with reference to the attached drawings.

FIG. 1 is a control circuit diagram of this embodiment that simultaneously damps bending motion and torsional vibration, FIG. 2 is a perspective view showing the overall configuration of the control system in FIG. 1, and FIG. is a plan view of the damping support device used in this example, and FIG.
It is a sectional view taken along line fV-■ in the figure.

In FIG. 2, a light emitting/receiving device 1 having a mass m at its tip
A cantilevered strip 2 having a diameter is fixed to a frame 4 via a damping support device 3 . When a disturbance enters the frame 4, bending vibrations M and torsional vibrations T in the directions shown in FIG. 2 appear conspicuously in the band plate 2. This is because the rigidity of the strip plate 2 is weak against these vibrations.

As shown in FIGS. 3 and 4, the damping support device 3 includes a piezoelectric actuator 5a as a displacement generating means, and an alternating force detector 5b as an alternating force detecting means arranged coaxially with the piezoelectric actuator 5a.
a damping support 5, and likewise a piezoelectric actuator 6a.

damping support 6, consisting of 7a and alternating force detectors 6b, 7b;
7 are spaced apart from each other in a star shape and arranged symmetrically with respect to point 0.

An upper plate 8 is disposed on one side of the piezoelectric actuators 5a, 5a, 7a, and alternating force detectors 5b, 6b.

A lower plate 9 is provided on one side of each plate 7b, and the upper plate 8 and the lower plate 9 are fastened together with a connecting bolt 10 and assembled into one piece. Note that h in the figure is the housing of the damping support device 3.

Alternating force detector 5b, 6b, 7b (7) output signal V f5
゜VF6. The VF6 is guided to the control device 11, and the piezoelectric actuators 5a, 6a, and 7a are connected to the control device 1.
1 to apply voltage signals to be described later.

When the frame 4 now vibrates, a vibration force acts on the damping support device 3. This is detected by the alternating force detectors 5b, 6b, and 7b, and the alternating force detection signal Vf5. VF6
．． The VF6 is guided to the control device 11.

In the control device 11, as shown in FIG. 2, the alternating force detection signal Vf5. VF6. VF6 is each subjected to sensitivity adjustment by a preamplifier pt l P2 + p3, and is applied to control circuits C1, C2, and C3, where it is input to time-related first-order integrators 12, 13, and 14, respectively. And piezoelectric actuators 5a, 5a, respectively.
, 7a require bias voltage power supplies 15', 16',
The bias voltage given from 17' is added to adder 15.16.
17, and is further amplified by amplifiers 18, 19, and 20 to produce an applied voltage signal Va5. Va6. Obtain Va7.
'This applied voltage signal Va5. Va6. When Va7 is applied to the piezoelectric actuators 5a, 6a, 7a,
Each piezoelectric actuator 5a, 5a, 7a expands and contracts with a phase delay of 90° with respect to the alternating force propagating through each piezoelectric actuator.

Relative displacement of both ends of each damping support 5, 6.7 X5+X5.
X7 is the spring constant of the damping supports 5, 6.7 and 3. 6.
7, piezoelectric actuator 5a.

6a, 7a, the amount of expansion and contraction u5, C6+C7, and the alternating force L5+L6. propagating through the damping support 5.6.7. L7
Using , each of these values is expressed by the relationship . Among these, the amount of expansion and contraction u5 of the piezoelectric actuators 5a, 6a, and 7a
．． u6. u7 is the alternating force L5. L6. L? The relationship between the alternating forces L5+ Ls, L7 and the relative displacements X5, X5, and X7 at both ends of the damping support 5.6.7 is shown in Figure 5. Thus, the energy in the shaded area is dissipated every - period. This dissipates the vibration energy and dampens the vibrations.

FIG. 6 is a graph diagram for explaining the effect of the active damping method of this embodiment. That is, FIG. 6(a) shows the displacement of the tip of the strip without any control, and FIG.
bl is the displacement of the tip of the strip when controlled by the control method of the embodiment.

As can be seen from the figure, the control of this embodiment causes rapid attenuation of the imaging.

[Embodiment 2] The active damping control means of Embodiment 2 will be explained below based on FIGS. 7 and 8.

The features used in Example 2 will be explained below in comparison with the apparatus shown in FIGS. 3 and 4 used in Example 1.

That is, the damping support device 30 of the second embodiment, like the damping support device 3 of the first embodiment, has piezoelectric actuators 5a, 6a, ? a
and alternating force detectors 5b, 6b.

7b arranged in series on the same axis.
．． 7 are arranged in parallel in a star shape symmetrically with respect to the 0 point.

Although not mentioned in the explanation of the first embodiment, FIG.

In the damping support device 3 shown in FIG. 4, the rigidity of the coupling bolt 10 is sufficiently small to be used. However, there are many cases in which the bending rigidity and tensile rigidity of the connecting bolt 10 cannot be ignored. At this time, three alternating force detectors 5b.

6b and 7b actuate the piezoelectric actuators 5a and 6a by applying a force excluding the force propagating through the coupling bolt 10 out of the force propagating through the damping support device 3.

The reaction force when the connecting bolt 10 is deformed by expanding and contracting 7a is also measured.

This reaction force is applied to the piezoelectric actuators 5a and 6a.

It is proportional to the amount of expansion and contraction of 7a. At this time, the alternating force detector 5b
, 6b, 7b alternating force detection signal V f5°VF6. V
In the control system using the control circuit shown in FIG. 1, which controls the amount of expansion and contraction of the piezoelectric actuators 5a, 5a, and 7a based on the signals obtained by first-order integration of F6, the piezoelectric force caused by this reaction force is generated in the low frequency band. Actuators 5a, 6a, 7a
The total amount of expansion and contraction x5. X5. The ratio to x7 is thick (becomes thick) and works to weaken the damping effect.

Therefore, in the second embodiment, in order to avoid the influence of the internal balance force (deformation reaction force of the coupling bolt 10) of the damping support W30, as shown in FIG.
a, 6a,? A steel plate 31 is inserted between A and the alternating force detectors 5b, 6b, and 7b to isolate them, and the upper plate 7 and the steel plate 31, and the lower plate 8 and the steel plate 31 are connected with different connecting bolts 32 and 33, respectively. Integrated damping support device 30
is used. Here, the piezoelectric actuator 5a and the alternating force detector 5b, the piezoelectric actuator 6a and the alternating force detector 6b, and the piezoelectric actuator 7a and the alternating force detector 7b.
and are arranged on the same axis as in the first embodiment.

With this configuration, the piezoelectric actuator 5
The deformation reaction force of the connecting bolt 32 due to the expansion and contraction of a, 6a, and 7a is canceled out as a balancing force between the upper plate 7 and the steel plate 31.

Therefore, the alternating force detectors 5b, 6b, and 7b are not affected by this (and can detect the force excluding the force propagating through the coupling bolt 33 among the alternating force propagating through the damping support device 30. The force applied to the damping support device 30 and the force propagating through the damping support device 30 can generally be considered to have a linear relationship.

The control circuit used in Example 2 was the same as that shown in FIG. Therefore, as explained above, each alternating force detector 5b, 6b, 7b has a preamplifier Ps, p2. P3
By adjusting the sensitivity according to the above, it is possible to measure by converting the force propagating through each damping support 5°6.7 of the damping support device 30. Therefore, the alternating force detectors 5b, 6b
, 7b, each alternating force detection signal Vf5. VF6
．． VF6 is applied to the piezoelectric actuators 5a, 6a, 7a through a control circuit as a voltage signal Va5. V
a6. Va7 is obtained and input to the piezoelectric actuators 5a, 6a, and 7a, respectively. At this time, the vibration energy is dissipated for the same reason as in the first embodiment, and the vibration is attenuated.

Although all of the above embodiments have been described using three damping support means, the method of the present invention is not limited thereto, and the method of the present invention is not limited to this, and the method may include two, four or more damping support means and an alternating force detection signal. A similarly effective active damping control can be achieved with independent control circuits including first-order integrator means.

〔Effect of the invention〕

As explained above, the active damping control method of the present invention includes a plurality of damping support means in which displacement generating means that expands and contracts to displace and alternating force detecting means that detects vibration propagating through the displacement generating means are arranged in series. to support the object to be vibration-isolated,
Since the configuration is such that the displacement of the corresponding displacement generating means is controlled based on the signal obtained by first-order integration with respect to time of the alternating force detection signal outputted by each of the alternating force detectors, multiple displacements can be generated. Bending vibration,
Vibration energy such as torsional vibration and shaft vibration can be effectively dissipated and excellent damping effects can be obtained.

Therefore, it becomes possible to expand the field of use of the active damping means.

[Brief explanation of the drawing]

Fig. 1 is a control circuit diagram in the form of a block diagram of an embodiment shown in the case of support at three points, Fig. 2 is a perspective view showing the overall configuration of one embodiment, and Fig. 3 is a damping support used in embodiment 1. A plan view of the device, FIG. 4 is a sectional view taken along the line IV-IV in FIG. 2, FIG. 7 is a plan view of the damping support device used in Example 2, and FIG. 8 is a cross-sectional view taken along the line ■-■ in FIG. 7. 3... damping support device, 5. 6. 7... Damping support, 5a, 6a, 7a---Piezoelectric actuator sX-layer, 5b
. 6b, 7b... Alternating force detector 1.12.13.14.
...1st-order integration circuit, Cs, C2, C3...control circuit, VfL VF6. VF3... Alternating force detection signal, V
al. Va2. Va3... Applied voltage control signal. Figure 1 Figure 2 Figure 3 Figure 4 ILs, L6. L7 Figure 7 Figure 8

Claims (1)

[Claims] Supporting an object to be vibration-isolated by using a plurality of damping support means in which a displacement generating means that expands and contracts and displaces and an alternating force detecting means that detects vibration propagated to the displacement generating means are arranged in series,
The alternating force detection signal outputted by each of the above-mentioned alternating force detection means,
An active damping control method, characterized in that the displacements of the corresponding displacement generating means are controlled based on signals obtained by first-order integration with respect to time.