JP3444638B2 - Control amount 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 device for controlling a controlled variable such as position, speed and force with high precision and speed,
Widely used for robots, precision processing machines, precision measuring devices, steppers, etc.

[0002]

2. Description of the Related Art In order to meet the demand for higher performance of the times, efforts have been made to control the controlled variables such as position, speed and force with high precision and speed in the field of mechatronics, particularly in the field of control. . Conventionally, as a device for controlling these control amounts, a semi-closed loop control composed of a drive system, a drive transmission system, an operating part, and a controller for controlling the drive system (a block diagram is shown in FIG. 1A). However, since it is not a mechanism for controlling the control amount by feeding back the information of the operation unit to the drive system, it is difficult to control the control amount of the operation unit with good reproducibility and high accuracy. In order to improve this, closed loop control (a block diagram is shown in FIG. 1 (b)) in which a sensor is provided in the actuating unit and information of the actuating unit is fed back to the drive system to control the control amount is introduced. Became. However, in this control, there are problems in the transmission system and the operating part such as speed reducer association, blurring and distortion due to the rigidity of the equipment used, and the higher the feedback gain, the more accurate the control gain. There is a drawback that the vibration becomes large and the control becomes difficult. In order to improve this, a control means utilizing the viscous force of the electrorheological fluid has been proposed.

The electrorheological fluid is a fluid whose viscosity is remarkably remarkably and reversibly changed by applying a voltage. By using such viscosity change of electrorheological fluid for control, quicker and more accurate control is possible compared with conventional control using mechanical force such as friction force, pressure, electromagnetic force, etc. or electric / mechanical force. Also, the mechanism is simple and compact.

Japanese Patent Application Laid-Open No. 64-78776 discloses a method of providing a damper using an electrorheological fluid at a joint portion of a robot and switching a damping constant to rapidly control vibration. JP-A-4-277335 discloses a method of applying a voltage to an electrorheological fluid interposed in a gap between a support member and a rotating movable member to apply a damping force to stop the movable member at a predetermined position. And a method of using a position control damper formed by interposing an electrorheological fluid in the gap between the movable member and the voltage applying timing. However, none of these suggestions
Instead of using the electrorheological fluid for feedback control, the increase in the viscosity of the electrorheological fluid is used as a mechanical restraining force to simply suppress the vibration (after the drive system is stopped in the latter two cases). It is only used for vibration damping.

On the other hand, Japanese Patent Laid-Open No. 4-158414 discloses
In an actuator equipped with a servo mechanism in the operation control system, a damping force based on the flow resistance of the electrorheological fluid is applied according to the deviation between the operation value (observed value) and the target value to accurately adjust the position and angle. A method of controlling is described. This method is similar to the closed loop control (a block diagram is shown in FIG. 2) and uses an electrorheological fluid in the auxiliary manufacturing system referred to in the present invention. .

[0006]

Although these control methods using the electrorheological fluid have some effects as compared with the conventional methods not using the electrorheological fluid, they do not perform the closed droop control. According to the methods disclosed in Japanese Patent Laid-Open No. 64-78776 and Japanese Patent Laid-Open No. 4-272529, vibration damping can be accelerated, but control with good absolute accuracy and reproducibility cannot be performed. It was also found that the method of Japanese Patent Application Laid-Open No. 4-158414, which performs the closed droop control, has a serious problem in order to improve the control accuracy. This problem will be described below by taking the case of using this method for positioning control as an example. That is, this method controls the position of the controlled object by exerting a damping force based on the viscous resistance of the electrorheological fluid according to the deviation (in this case, the distance or the angle) between the target value and the operation value (observed value) to be made stationary. In order to develop a viscous resistance corresponding to this deviation in the electrorheological fluid, the deviation is measured every moment, and the voltage applied to the electrorheological fluid is adjusted every moment so as to develop the viscous resistance corresponding to the deviation ( In the description of the specification, it is stated that a larger voltage is applied as the deviation becomes smaller. Generally, when the controlled object is stopped at the target position, it is necessary to decrease the moving speed of the controlled object as it approaches the target value.
In particular, when performing highly precise positioning control in the micron unit, the moving speed before and after the standstill becomes extremely low.
The positioning control by the above method requires an extremely high-precision position sensor for detecting this minute deviation, and further, a controller for adjusting the voltage applied to the electrorheological fluid corresponding to this minute deviation is required. I need. However, in reality, such a high-performance position sensor is extremely expensive, and it is difficult to adjust the applied voltage momentarily according to minute deviations.

Further, in this publication, a particle dispersion type fluid is used as the electrorheological fluid. However, since this type of fluid exhibits Bingham fluid flow behavior, the apparent viscosity rapidly increases as the shear rate decreases. There is a rising feature. Therefore, in such a control method, the apparent viscosity rises sharply as the controlled object approaches the target position and its speed decreases, and even if a constant voltage is applied (the applied voltage is adjusted according to the above deviation). Even if the viscosity is increased), the damping force becomes too large before the stationary state, and the so-called Coulomb frictional stationary state is involved, so that precise positioning is essentially difficult.

An object of the present invention is to provide a device for controlling a controlled variable such as position, force, speed, etc. with high precision and speed by closed feedback control equipped with a new control stabilizing system using an electrorheological fluid. To provide.

[0009]

According to the inventors of the present invention, the damping force required before and after the controlled object is stopped or started by fine adjustment corresponds to the deviation between the target value and the observed value in the above-described precise positioning control. It was thought that the above problems could be solved by applying an electrorheological fluid that exerts such a damping force to the control, rather than the generated force, which is a force proportional to the speed of the controlled object. Then, they found that a certain kind of liquid crystalline polymer can be an electrorheological fluid that exhibits a shear stress proportional to the shear rate when a voltage is applied, that is, a so-called Newtonian fluid flow behavior, and a synthesis method thereof. As a result of repeated studies on a method and apparatus for controlling a controlled variable such as position, speed, force, speed, etc. using this electrorheological fluid, it becomes possible to realize an extremely good control apparatus and reach the present invention. I was able to.

That is, the present invention comprises a controlled object including a drive system, a transmission system and an actuation unit, a controller, a sensor provided in the actuation unit or the transmission system, and a control stabilization system. In a device that feeds back to a controller to control a controlled variable, an electrorheological fluid that exhibits Newtonian flow when a voltage is applied is used in the control stabilization system, and an electrorheological fluid is generated by a signal from the controller. A controlled variable control device characterized in that a controlled object is stabilized by applying a predetermined constant voltage to the control target. A block diagram of a typical example of the device of the present invention is shown in FIG.

The drive system referred to in the present invention is a system such as a motor, a solenoid, a cylinder, etc. for rotating or rectilinearly moving to drive an operating part by energy such as electromagnetic force, air pressure, hydraulic pressure, etc. In the present invention, It is preferable that the device itself has a sensor function such as an encoder, a linear scale, a tachogenerator, and a servo valve. Further, the transmission system means a shaft, rod, arm, linear guide, speed reducer, clutch, gear, torque converter, transmission, joint, flange, belt, wire, and button for transmitting the energy of the drive system to the operating portion. It is a system that consists of any combination of a screw and a bearing.

The actuating portion is a portion where a controlled amount of controlled position, force, speed, etc. in the device of the present invention acts on an object outside the device. In the robot, joints and arms are used.
In the case of a stepper, it refers to the exposure device portion or the like. The controller referred to in the present invention is composed of a hard part and a computer soft part, and controls the operation of the control stabilizing system based on the information of the controlled variable from the sensor provided in the transmission system or the operating part. Say something. Specifically, the timing of applying or releasing a voltage to the electrorheological fluid and the strength of the applied voltage (these are based on the data stored in advance in the computer of the controller) are set, and the voltage is applied. And release. These may be performed stepwise in order to avoid a shock due to sudden application or release of voltage. The controller also controls the drive system as well as the control stabilization system.

The sensor provided in the transmission system or the operating section is for detecting a controlled variable such as position, force, speed and the like and feeding back the information to the controller. The wavelength, strain, resistance, pressure, Observe changes in physical quantities such as twist, distance, speed,
Detect pressure, tension, etc. The control stabilization system according to the present invention is a system for exerting a damping effect by flow resistance against movement or vibration of a transmission system or an operating portion, and controlling the control amount quickly and highly accurately. In this system, a movable part that is connected to a transmission system or an operating part and rotates, rectilinearly, or reciprocally moves with it, and a fixed part that is separated from the movable part through a substantially constant gap (independently from the movable part in some cases). Electrodes are formed on the facing surfaces of the movable portion and the fixed portion, and an electrorheological fluid is sealed in the gap.
By applying a voltage to this electrorheological fluid, the viscous resistance applied to the movable portion increases, and the movement of the movable portion becomes heavy.
This stabilizes the drive system and the controlled object and enables the use of a controller with a higher gain. The stabilization system is triggered by a signal from the controller (eg, when the controlled variable reaches a predetermined range). As a method of starting, the time required for the controlled variable to reach a predetermined range is experimentally obtained in advance,
There is a method of starting at this time. The operation of the control stabilization system takes place under closed-loop control.

The controlled variable in the present invention means position (or angle), speed (or angular speed), force (or torque), or the like. The electrorheological fluid exhibiting Newtonian flow referred to in the present invention is a fluid exhibiting a shear stress proportional to the shear rate when a voltage is applied, and the viscosity when a voltage is applied satisfies the following equation.

Τ = η (D−D ₀ ) ⁿ + C Equation (1) where τ is the shear stress [Pa], η is the apparent viscosity [Pa · sec], and D is the shear rate [sec ⁻¹ ]. , D ₀ is a delay value [sec ⁻¹ ], n is a coefficient [positive real number], and C
Is the yield stress [Pa], and the preferable range is that n is 0.
8 ≦ n ≦ 1.5, more preferably 0.9 ≦ n ≦ 1.
2, C is 0 ≦ C ≦ 300, more preferably 0 ≦ C ≦ 1
00 (value when voltage of 3 kv / mm is applied), D ₀ is 0 ≦
D ₀ ≦ 50. It is desirable that the apparent viscosity η be as large as possible, but even if it is small, the value (η
_The larger the ratio η / η _off , which is the ratio of _off ), the more effectively it can be used in the present invention. Yield stress C
Is 300 to 1000 in a conventional particle-dispersed electrorheological fluid, for example, a hydrous silica particle dispersion, and 1000 to 5000 in a water-containing ion exchange resin particle dispersion.
The electrorheological fluid showing the Newtonian flow used in the present invention is 300 or less, and the one close to zero is more preferable.
The delay value D ₀ tends to increase a little when the applied voltage is low, but a low value is preferable. Also, in equation (1), the shear rate D
In the region where D is lower than D ₀ , D−D ₀ is regarded as zero.

In the case of performing the positioning control, the present invention is intended for the mechanical restraining force when approaching a stationary state, and the above equation (1) has a shear rate of 0 to 50 [sec].
^-1 ] is recommended. A typical electrorheological fluid that exhibits such viscous behavior is, for example, a thermotropic liquid crystal composed of a certain compound. Examples of the compound include a liquid crystal compound in which a plurality of liquid crystal groups are bonded to a flexible molecular chain such as silicone, which are specifically described in Japanese Patent Application No. 3-220064. ing.

Since a liquid crystal compound in which a plurality of liquid crystal groups are bonded to a flexible molecular chain such as silicone is not one in which particles are dispersed, there is no problem of particle sedimentation and particle abrasion, and thus a uniform system electric A viscous fluid is particularly preferred. Heretofore, a polar liquid such as nitrobenzene (Japan. J. Appl. Phys. 16) has been used as a homogeneous electrorheological fluid.
1775 (1977), cholesteric liquid crystal mixture (Communications 3865 (196).
5)) and methoxybenzylidene butylaniline (MBB
A) such as low molecular weight liquid crystal (Japan. J. Appl. P)
hys. 171525 (1978) and GB220
8515A), a ferroelectric polymer solution (proceedings of the 39th Symposium on Polymers, 18U07, 1990) and the like, but these electrorheological fluids can also be used.

In general, when an external force is applied to a moving object to make it stand still, the force required to stand still is proportional to the speed of the object. By controlling the controlled object with a force (damping force) proportional to this speed, the control value can be smoothly and stably controlled to the target value. The electrorheological fluid used in the present invention is
Since the Newtonian flow, that is, the shear stress has a characteristic that it is proportional to the shear rate, the damping force required to make the controlled object stand still at a predetermined position is based on the relationship between the applied voltage and the viscosity of the fluid obtained in advance. Even if the speed changes momentarily, it is possible to automatically obtain a damping force proportional to the speed without adjusting the applied voltage in accordance with the constant voltage, which is determined by the above. Therefore, the control device of the present invention is extremely convenient for high-precision positioning control,
It can be said that it is also convenient for controlling force (the force detection is basically the position or the amount of change in the position). Furthermore, the control device according to the invention can also be applied to speed, in particular speed stabilization. For example, when the rotation speed of the rotating body is increased to a high speed range according to a certain program, a resonance phenomenon is generated at a certain rotation speed, but this resonance is effectively suppressed by operating the control stabilization system of the present invention. It will be possible. Further, in general, it is difficult to accurately control an extremely low speed, for example, 10 mm / min, but the control according to the present invention makes it possible.

Further, from the characteristics of the Newtonian fluid, for example,
When exercising at a certain set speed (acceleration), when the speed becomes faster than the set value, a large suppression force works, and when the speed becomes slower, the suppression force becomes smaller and the speed (acceleration) becomes the set value. It has a so-called self-regulating function of holding and can be preferably used for speed control. When designing a control system, it is important to allow for errors and uncertainties in the mathematical model, absorb the characteristic fluctuations of the controlled object to some extent, and robust stability that does not degrade performance. As a control theory in consideration of robust stability and robust control performance, the robust control theory developed in recent years is used in combination with the control device using the electrorheological fluid showing the Newtonian flow of the present invention, whereby the control speed is increased. It has been found that an extremely large synergistic effect is exhibited in improving the precision and accuracy. The concept of the combination of robust control theory and electrorheological fluid will be described below.

The mathematical model obtained for controlling is represented by the transfer function Po (s). However, a model error Δ (s) always exists between this mathematical model and the actual transfer function P (s) of the controlled object. That is, P (s) = Po (s) + Δ (s) Formula (2) This model error Δ is expressed by the frequency weighting function W (j
ω).

[0021] | Δ (jω) | <| W (jω) | Equation (3) At this time, the relationship shown below

[0022]

[Equation 1]

If a compensator C satisfying the above condition is obtained, the system becomes robustly stable. That is, the stability of the closed loop system is guaranteed even if the model fluctuates within the range satisfying the expression (3). Further, the expression (4) means that it is necessary to reduce the gain characteristic of the controller in the frequency band where the degree of uncertainty is high (the gain characteristic of W is large). Generally, in mechanical systems, due to the elasticity etc. existing in each part,
In many cases, the gain characteristic in the frequency response has a peak, and this resonance peak makes the control very difficult. An electrorheological fluid exhibiting a Newtonian flow can keep this peak low due to its viscous characteristics. As a result, the gain characteristic of W that suppresses the model error Δ as in Expression (3) can be reduced. as a result,
The gain characteristic of the controller can be raised sufficiently, and the closed loop
It is possible to improve the response performance of the system. Note that the robust control theory referred to in the present invention is expressed by equations (2), (3) and (4).
Is a control theory based on, and applications based on this theory are also included in the present invention.

For details of the robust control theory, see Peter Dorato, "Robust c.
ontrol "IEEE Press (1987).

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to explain the present invention in detail, the embodiments will be described below with reference to the drawings.

[0026]

[Embodiment 1] FIG. 4 schematically shows an apparatus equipped with a velocity and positioning control mechanism using an electrorheological fluid (which can be applied to many mechatronics devices including a joint part of a robot arm). The robot arm 4 is attached and fixed to the output side shaft 3 of the decelerator 2, and the servo motor-1
Driven by a circular motion. A control mechanism using an electrorheological fluid including a pair of lower flange 6 and upper flange 9 is attached to the upper end of the shaft 3. A wide ring-shaped flat groove is engraved on the upper surface of the lower flange 6 fixed to the shaft 3, and the ring-shaped electrode plate 5 (which is electrically insulated from the flange 6 by an insulating material) is formed in the groove. Is attached (fixed). On the other hand, the ring-shaped electrode plate 8 is also formed on the lower surface of the flange 9 attached to the shaft 3 via the bearing 10.
(It is electrically insulated from the flange 9 by an insulating material). An electrorheological fluid 7 is sealed in a parallel and constant gap (1.0 mm) between the pair of electrode plates, and a voltage is applied by a power source 14. The upper flange 9 is fixed to the rigid frame 11.

In the drive control of the robot arm 4 with rough accuracy, it is controlled by the control mechanism attached to the servomotor 1, and no voltage is applied to the electrorheological fluid. When controlling the speed and positioning with high accuracy, or when controlling the robot arm 4 at low speed and with high accuracy,
A voltage is applied to the electrorheological fluid based on a signal fed back from the position (or angle) sensor 12 to the motor 1 to control the electrorheological fluid.

FIG. 5 shows a block diagram of the control system of this apparatus. X is the amount that you want to perform precise positioning, F (X ', Vi
n) is a function representing the driving force determined by the relationship between the shear rate X'and the applied voltage Vin. In the electrorheological fluid showing the Newtonian fluid viscous behavior used in the present invention, since the function F is almost linear with respect to the shear rate X ′, the control system is easily stabilized, and highly accurate positioning control is possible. Become. In addition,
The applied voltage Vin is applied just before performing the fine positioning.

FIG. 6 shows the conventional Bingham fluid flow behavior when the side chain type liquid crystalline silicone compound having the Newtonian fluid flow behavior of the present invention is used as the electrorheological fluid (a). This is a comparison of the stationary state after reaching the vicinity of the target stop position of the robot arm in the case of using a particle dispersion system (b). The evaluation was made by driving the robot arm 4 at a constant speed with the motor-1 and setting the control condition of the servo motor so that the robot arm 4 was stopped at a predetermined position. A predetermined voltage was applied to the electrorheological fluid. In (b), the position of the stopping process should be detected originally, and the signal should be fed back to the control device and converted into speed information, and then the voltage corresponding to this should be calculated moment by moment to feed back to the electrorheological fluid. This must be done, but this evaluation was performed by applying a predetermined constant voltage to both (a) and (b).

The electrorheological fluid used had the following composition. (A) was evaluated at 60 ° C. and (b) was evaluated at 30 ° C. Side chain type liquid crystalline silicone: A compound of the structure shown in Chemical Formula 1 diluted with 50 parts by weight of dimethyl silicone (100 cst).

[0031]

[Chemical 1]

Particle-dispersed electrorheological fluid: 30 parts by weight of spherical silica particles (particle size: about 5 μm, water content: 7 wt%) dispersed in dimethyl silicone (20 cst).

[0033]

Second Embodiment FIG. 7 shows a model diagram of an air-servo cylinder equipped with a velocity and positioning control mechanism using an electrorheological fluid. It has a structure in which a servo cylinder part driven by air pressure and a damper part using an electrorheological fluid are connected by one shaft 1. A servo valve (not shown in the drawings) is attached to each of the air supply port 2 and the air discharge port 3 in the cylinder portion, and the drive of the shaft 1 is controlled by the difference in air pressure between the left and right of the piston 4.
The damper portion has a double cylindrical structure, and an electrode 5 electrically insulated from the cylinder body and the shaft 1 is formed on the entire outer surface of the inner cylinder. Further, many holes 6 are formed at both ends of the inner cylinder so that the electrorheological fluid 8 on the left and right of the piston 7 can move through the gap of the double cylinder. Aerated outer cylinder (made of metal)
The inner surface of the electrode becomes the electrode on the ground side, and the gap with the electrode 5 (2 m
A predetermined voltage can be applied from the power source 9 to the electrorheological fluid existing in m). The movement of the shaft 1 is measured by a position sensor-10, and its signal is sent to a control device (not shown in the drawing).

FIG. 8 shows the state of movement of the shaft when the shaft is moved at a constant speed of 10 mm / min. (A) is a case where a side chain type liquid crystalline silicone compound showing the Newtonian fluid flow behavior of the present invention is used for an electrorheological fluid, and (b) is a particle dispersion showing a conventional Bingham fluid flow behavior. (C) shows the case where the electrorheological fluid of the system is used, and the case where the electrorheological fluid is not used at all. A method of constantly applying a constant voltage to the electrorheological fluid is repeatedly performed by changing the voltage value, and the best example of the results is shown. The same electrorheological fluid as in Example 1 was used. Further, the control condition of the servo valve is set so that the shaft driven at a constant speed (1 m / sec) is stopped at a predetermined position, and a predetermined amount of electrorheological fluid is applied to the electrorheological fluid about 0.5 seconds before the scheduled stop. When a voltage was applied and the stationary state after the target stationary position was reached was examined, (a) was extremely low as in Example 1.
Although it stopped at the target position within 5 seconds with an error of about 10 μm, (b) took about 2 seconds and was about 60 μm, and (c) was not stable even after 3 seconds and stopped with an error of 130 μm.

[0035]

[Embodiment 3] An apparatus in which a control system shown in the block diagram of FIG. 9 using an electrorheological fluid is applied to positioning control of a drive system (including a linear type) using a direct drive motor. High-precision control can be performed quickly. When the control amount X is about to deviate from the target value Xr due to disturbance or the like, the original target value Xr is generated by the powerful force (torque) of the motor.
In order to carry out a control method for restoring the motor speed (called high rigidity control), it is necessary to feed back the angular velocity X'of the motor with a high gain, and then feed back the angle X with a high gain. In the conventional motor control, the angular velocity X ′ is often not directly measured but the angles X to X ′ are approximately obtained because of cost or technical difficulty. With such a method, it is difficult to obtain high-quality angular velocity information at low rotation speeds, and thus high gain feedback is difficult. As a result, it becomes difficult to perform high gain feedback of the angle X, and realization of high rigidity control is hindered. In the present embodiment, it is possible to feed back the angle X with a high gain by substituting a part of the velocity feedback with an electrorheological fluid. Since the electrorheological fluid whose shear stress is almost proportional to the shear rate is used, the applied voltage Vin can be easily controlled.

In order to increase the speed of industrial machines (including robots and machine tools), it is desirable to reduce the reduction ratio of the motor as much as possible, and the limit is the direct drive motor.
It is a target. In a low reduction ratio system, one problem is to increase servo rigidity, and this embodiment is extremely effective in solving this problem.

[0037]

Example 4 The controllability was examined by combining the experiment using the electrorheological fluid showing the Newtonian flow of Example 1 with the robust control theory. For the setting of the experimental condition, frequency weighting function W, compensator C, etc. for enhancing robust stability, the 11th Proceedings of the Robotics Society of Japan, N,
o. 11, 2B22 (1993). FIG. 10 shows the behavior of the arm stopping process. (A) shows the result of the example which combined robust control theory, (b) shows the result of the comparative example which applied only robust control theory without using electrorheological fluid. From this, it can be understood that (a) can be stopped at the target position in a much shorter time than (b).

[0038]

The apparatus of the present invention stabilizes a controlled object by using an electrorheological fluid that exhibits a Newtonian flow that naturally exerts a damping force proportional to the speed by applying a constant voltage to a control stabilization system. It is possible to control the controlled variables such as position, speed, force, and the like. Therefore, it becomes possible to perform control which has been difficult to achieve in the past with high precision and speed, and it can be widely used for robots, precision processing machines, precision measuring devices, steppers and the like.

[Brief description of drawings]

FIG. 1 is a block diagram of a conventional device control system.

FIG. 2 is a block diagram of another conventional control system.

FIG. 3 is a block diagram of an example of a control system of the present invention.

FIG. 4 is a model diagram of a drive device for the robot arm according to the first embodiment.

5 is a block diagram of a control system of the apparatus shown in FIG.

FIG. 6 is a graph showing the behavior of the arm stopping process.

FIG. 7 is a model diagram of a servo cylinder according to the second embodiment.

FIG. 8 is a movement state diagram of the shaft when the shaft is moved in a constant low speed experiment.

FIG. 9 is a control block diagram when adapted to a direct drive system.

FIG. 10 is a graph showing the behavior of the arm stopping process under the control combined with the robust control theory in the fourth embodiment.

[Explanation of symbols]

1 Servo motor 2 reducer 3 shuffs 4 robot arm 5 electrode plate 6 Lower flange 7 Electro-rheological fluid 8 electrodes 9 Upper flange 10 bearings 11 rigid frame 12 Position (angle) sensor 13 power supply 14 holes 15 Supply port 16 exhaust port 17 pistons 18 Inner cylindrical electrode

─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-4-158414 (JP, A) JP-A-4-194328 (JP, A) JP-A-4-191511 (JP, A) JP-A-2- 300525 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G05D 3/00-3/20

Claims (6)

(57) [Claims] 1. A control object comprising a drive system, a transmission system and an actuation unit, a controller, a sensor provided in the actuation unit or the transmission system, and a control stabilization system. Information from the sensor is fed to the controller. In an apparatus for controlling a controlled variable by performing a feedback, an electrorheological fluid that exhibits Newtonian flow when a voltage is applied is used in the control stabilization system, and a predetermined constant is applied to the electrorheological fluid according to a signal from a controller. A controlled variable control device characterized in that a voltage is applied to stabilize a controlled object. 2. The controlled variable control device according to claim 1, wherein the controlled variable is position. 3. The controlled variable control device according to claim 1, wherein the controlled variable is force. 4. The controlled variable control device according to claim 1, wherein the controlled variable is speed. 5. The controlled variable control device according to claim 1, wherein the electrorheological fluid exhibiting Newtonian flow is a liquid crystalline substance. 6. The controlled variable control apparatus according to claim 1, wherein the controlled variable is controlled by incorporating a robust control theory.