JPH04370407A - Actuator controller - Google Patents

Abstract

PURPOSE:To provide an actuator controller capable of detecting the state of an actuator in contact with an article without providing the actuator itself with any sensor. CONSTITUTION:Using an actuator 1 comprising a cylindrical elasticbody 8 whose interior is divided into a plurality of pressure chambers 14 to 16 by bulkheads, a means to detect the pressure in the pressure chambers 14 to 16 and a means to detect the volumes of the pressure chambers 14 to 16 are provided. The resultant pressure P and volume V are detected, and the detected values are compared with the predetermined curved line PV of the actuator 1. Any possible difference between them suggests that the actuator 1 is brought into contact with some article.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an actuator control device for controlling an actuator that performs operations such as bending, expansion and contraction using fluid pressure energy.

0002

[Prior Art] It consists of a cylindrical elastic body whose interior is separated into a plurality of pressure chambers by a partition wall, and arbitrary movements such as bending, expansion and contraction are performed by supplying fluid pressure to the pressure chambers of this cylindrical elastic body. As an actuator, for example, JP-A-1-
The one described in No. 247809 is known.

[0003] In the above-mentioned actuator, by applying a large pressure to any one of the pressure chambers formed inside the cylindrical elastic body, the pressure chamber is expanded. That is, the cylindrical elastic body can be curved in any direction by the difference in pressure applied to each pressure chamber. Furthermore, if the pressure in each pressure chamber is simultaneously increased, the cylindrical elastic body will expand again, and if it is decreased, it will contract. In other words, depending on the total amount of pressure applied to the cylindrical elastic body,
The cylindrical elastic body can be expanded and contracted in any direction.

[0004] Since such an actuator is made of an elastic member, it has the characteristic that even if it comes into contact with an object, it will not damage the object or apply excessive force. However, on the other hand, in order to accurately detect the state in which the actuator is in contact with an object, it is necessary to attach a tactile sensor to the tip of the actuator. In such a case, since it is necessary to bring the tactile sensor into direct contact with the object, there is a risk that the elastic characteristics of the actuator cannot be utilized.

[0005]

[Problems to be Solved by the Invention] As described above, conventional actuators are composed of elastic members, so they have the characteristic that even when they come into contact with an object, they do not damage the object or apply excessive force. . However, in order to accurately detect when the actuator is in contact with an object, a tactile sensor must be attached to the tip of the actuator, and in such cases, it is necessary to directly contact the tactile sensor with the object. Therefore, there was a fear that the elastic properties of the actuator could not be utilized.

The present invention has been made to solve these conventional problems, and it is an object of the present invention to provide an actuator control device that can detect the state of contact with an object without attaching a sensor to the actuator itself. The purpose is

[0007]

[Means for Solving the Problems] In order to achieve the above object, in the present invention, the pressure in each pressure chamber of an actuator is made of a cylindrical elastic body whose interior is separated into a plurality of pressure chambers by a partition wall. In an actuator control device that controls drive of the actuator by adjusting, in order to detect a deformed state of the actuator, means for detecting the pressure of at least one of the pressure chambers, and a volume of the pressure chamber. The configuration includes a means for detecting.

[0008]

[Operation] Since the actuator is composed of an elastic member, under normal conditions when it is not in contact with (interference with) an object,
There is a certain correlation between the pressure P of the fluid supplied to the pressure chamber and the corresponding volume V of the pressure chamber (Figure 4
reference). According to the present invention, it is possible to detect the pressure in the pressure chamber and the volume of the pressure chamber when the actuator is operating, so compare these with the above correlation and if there is a difference between the two, the actuator is in contact with an object. It can be seen that This makes it possible to determine whether the actuator is in contact with an object without attaching a sensor to the actuator itself.

[0009]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a control device for an actuator according to an embodiment of the present invention, FIGS. 2 and 3 are an exploded perspective view and a sectional view of the actuator, and FIG. 4 is an explanatory diagram of the operation of the actuator. First, Figure 2, Figure 3, Figure 4
The actuator 1 used in the present invention will be explained using the following.

As shown in the figure, the actuator 1 is composed of a cylindrical elastic body 8 forming an outer wall, a tip sealing part 9, a root sealing part 10, and a tube 11. As can be seen from the figure, the cylindrical elastic body 8 is composed of three unit cylindrical elastic bodies 13a, 13b, 13c having the same shape.
These are integrally molded by adhering them in parallel in the axial direction. For this reason, elastic partition walls 5, 6, 7 are extended in the axial direction of the cylindrical elastic body 8 by the bonded parts,
These elastic partition walls 5, 6, 7 create two pressure chambers 14,
15 and 16 are formed. the unit cylindrical elastic body 13a,
13b and 13c are fibers 17 that are wound in a spiral shape with close spacing around the axis perpendicular to the drawing in FIG.
It is coated with silicone rubber, which is an elastic material. Therefore, since the cylindrical elastic body 8 is formed of an anisotropic elastic material made of a composite of fibers 17 and rubber, the direction of low rigidity approximately coincides with the axial direction 18 of the cylindrical elastic body 8. It becomes easier to stretch. Further, in the direction 19 perpendicular to the axial direction 18, the fibers 17 have high rigidity, making it difficult to stretch.

The tip sealing portion 9 includes fan-shaped upper lids 9a, 9b formed of metal or the like and sealing the pressure chambers 14, 15, 16 formed in the unit cylindrical elastic bodies 13a, 13b, 13c. One end of 9c is connected to unit cylindrical elastic body 13a,
13b, 13c and is constructed by inserting and adhering them.

The root sealing part 10 has fan-shaped lower lids 10a, 10b, 10c similar to the tip sealing part 9, and one end of the lower lids 10a, 10b, 10c is connected to unit cylindrical elastic bodies 13a, 13b. , 13c and adhesively sealed.

Further, the lower lids 10a, 10b, 10c are provided with insertion holes 20a, 20b, 20c, respectively, into which the tubes 11a, 11b, 11c are inserted and fixed. The tubes 11a, 11b, 11c are hermetically fixed to the insertion holes 20a, 20b, 20c with adhesive.

Actuator 1 configured as described above
For example, assume that the pressure in the pressure chamber 14 is increased by feeding working fluid from the tube 11a. In this way, the pressure chamber 14 extends in the axial direction, and the cylindrical elastic body 8
It curves in the direction shown by the chain line. In this state, if the pressure in the pressure chamber 16 is further increased via the tube 11c, the cylindrical elastic body 8 will curve in the B direction. In this way, by combining the pressures applied to the three pressure chambers 14, 15, and 16, the cylindrical elastic body 8 can be bent in any direction.

Furthermore, if the pressures in the three pressure chambers 14, 15, and 16 are increased equally, the cylindrical elastic body 8 will expand in the axial direction 18, and if it is decreased equally, it will contract in the axial direction 18. In other words, the cylindrical elastic body 8 can be expanded or contracted depending on the total amount of pressure applied to the cylindrical elastic body 8. Next, the actuator control device will be explained.

As shown in FIG. 1, tubes 11a, 11b, 11c extending from the actuator 1 are connected to cylinders 21a, 21b via various instruments (described later).
, 21c, respectively. cylinder 21a,
21b, 21c Inside there are pistons 22a, 22b, 2
2c are arranged and can be moved inside the cylinders 21a, 21b, 21c by linearly driving the rods 23a, 23b, 23c. In addition, the pistons 22a, 22b, 22c and the cylinder 2
1a, 21b, 21c, and rods 23a, 23b
, 23c and the cylinders 21a, 21b, 21c are sufficiently sealed, and the interiors of the cylinders 21a, 21b, 21c are kept airtight.

Driving portions 24a, 24b, 24c for linearly driving these rods 23a, 23b, 23c are arranged at the other ends of the rods 23a, 23b, 23c. The drive units 24a, 24b, 24c are rotary motors 24a', 24b', 24c' and
Ball screws 24a'', 24b'' for converting rotational motion of 24a', 24b', 24c' into linear motion
, 24c''.

The rotary motors 24a', 24b', 24c' of the drive units 24a, 24b, 24c are used to bring the actuator 1 into a desired deformation state by driving the rotary motors 24a', 24b', 24c'. Drivers 26a, 26b, and 26c are connected. Signals from the controller 31 are input to the drivers 26a, 26b, and 26c.

Further, potentiometers 25a, 25b, 25c are arranged to detect the length of movement of the rods 23a, 23b, 23c in the axial direction, and their outputs are input to the controller 31. . Potentiometers 25a, 25b, 25c are cylinder 2
1a, 21b, 21c, in other words, the pressure chamber 14
, 15, 16.

On the other hand, since most of the actuator 1 is made of elastic members, it is conceivable that cracks may occur and fluid may leak due to long-term use or frequent use. To prevent this, actuator 1
The tubes 11a, 11b, 11c connecting the cylinders 21a, 21b, 21c are equipped with pressure gauges 27a, 27b, 27c and check valves 28a, 28b, respectively.
, 28c, working fluid reservoirs 29a, 29b, 29c,
Pressure limit valves 30a, 30b, 30c are interposed. That is, these are used to maintain the functions of the actuator 1. Pressure gauges 27a, 27b, 27c are connected to tubes 11a, 1
1b, 11c, in other words, pressure chamber 1
It operates as means for detecting pressures P of 4, 15, and 16.

The check valves 28a, 28b, 28c have working fluid reservoirs 29 in which reserve fluid is secured at a predetermined pressure.
a, 29b, and 29c are connected, so that even if fluid leaks from the actuator 1, the leakage can be replenished and the pressure can be increased. Note that a high-pressure working fluid source can also be connected as the working fluid reservoirs 29a, 29b, and 29c.

[0022] In this way, the check valves 28a, 2
Even when the pressure chambers 8b and 28c are open, the pressure chambers 14 and
The pressures at 15 and 16 are detected by pressure gauges 27a, 27b, and 27c. Then, when the pressure in the pressure chambers 14, 15, 16 reaches a predetermined pressure, the pressure chambers 14, 15, 16,
In order to prevent the pressure limit valves 30a, 30b, and 30c from being excessively pressurized, the working fluid is controlled to be exhausted by opening the pressure limit valves 30a, 30b, and 30c. The operation of this embodiment having the above configuration will be explained.

Now, as shown in FIG.
2b, 22c are located at intermediate positions in the axial direction within the cylinders 21a, 21b, 21c, and in this state, the actuator 1
Assume that it has been stretched back in its axial direction but is not curved. Here, an arbitrary deformation state of the actuator 1 is input using the controller 31. The controller 31 applies this input signal to the drivers 26a, 26b, and 26c, and outputs a current for rotating the rotary motors 24a', 24b', and 24c' by a predetermined amount. This rotational movement is performed by ball screws 24a", 24b", 24c"
As a result, the cylinder 21
Pistons 22a, 22b, 2 inside a, 21b, 21c
2c will move in a straight line by a predetermined amount. When the pressure in the space inside the cylinders 21a, 21b, 21c changes due to the linear movement of the pistons 22a, 22b, 22c, this pressure change extends to each pressure chamber 14, 15, 16 of the actuator 1. Performs bending and expansion/contraction movements. In other words, the controller 31
The amount of curvature, expansion and contraction, etc. is input into the actuator 1, and this information becomes an electric signal and a pressure signal and is realized as the actual deformation state of the actuator 1.

When changing the deformation state of the actuator 1, the input to the controller 31 is changed. As a result, the pressure in the space inside the cylinders 21a, 21b, 21c changes, and different deformation states are realized in the actuator 1.

FIG. 5 shows the normal state of the actuator (
The relationship between the pressure P acting on the pressure chamber and the volume V of the pressure chamber in a state in which the pressure chamber is not in contact with an object is shown. (In this actuator 1, the relationships shown by the solid lines in the figure are established in the respective pressure chambers 14, 15, and 16.) In the figure, the origin indicates the volume at atmospheric pressure. Such a correlation is input into the controller 31 in advance as a reference value, and
1, a comparison with the measured values Pm and Vm is performed.

[0026] For example, when the actuator 1
, volume V1 and comes into contact with an object, the correlation between P and V will collapse, as shown by the chain line in FIG. This is because when the actuator 1 comes into contact with an object, the ratio of volume increase to pressing force is suppressed. In this way, Pm is detected by the pressure gauges 27a, 27b, 27c, and Vm is detected by the potentiometers 25a, 25b, 25c.
By detecting these and comparing them with reference values within the controller 31 based on these detection results, it is possible to know that the actuator 1 has come into contact with an object.

Furthermore, by using the difference between the reference value and the actual measurement value, the contact pressure between the actuator and the object can be determined. In this case, when the difference between the two is large, the contact pressure is large, and when the difference between the two is small, the contact pressure is small.

Furthermore, since the actuator is an elastic member, the relationship between P and V may not match when the pressure chamber is pressurized and when it is depressurized due to hysteresis. In such a case, it is preferable to prepare respective reference value curves (for example, the respective curves shown by the solid line and the dashed-dotted line in FIG. 5) for pressurization and depressurization.

Note that the controller 31 includes information on the deformation state of the actuator 1 and the pistons 22a, 22b, 2.
Drive amount of 2c (rotary motor 24a', 24b', 2
4c' rotation amount) can be programmed in advance, or the actuator 1 can be directly operated using a joystick lever or the like. Further, the detection data obtained by the controller 31 is given to each driver 26a, 26b, 26c to drive the actuator 1.
It is also possible to perform feedback control.

[0030] The actuator in the present invention has three
Although the actuator has one pressure chamber, it is of course also possible to use an actuator with two or more pressure chambers. In addition, the potentiometers 25a and 25b
, 25c, the volume V can also be detected using a flow meter or the like.

[0031]

As described above, according to the present invention, it is possible to determine whether an actuator is in contact with an object without attaching a sensor to the actuator itself.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an actuator control device according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of an actuator according to the present invention.

FIG. 3 is a sectional view of an actuator according to the present invention.

FIG. 4 is an explanatory diagram of the operation of the actuator according to the present invention.

[Figure 5] Pressure P acting on the pressure chamber of the actuator
The figure which shows the relationship of the volume V of a pressure chamber with respect to V.

[Explanation of symbols]

1 Actuator 14, 15, 16 Pressure chamber 21 Cylinder 22 Piston 25 Potentiometer 26 Driver 27 Pressure gauge 31 Controller

Claims (3)

[Claims] 1. An actuator control device for driving and controlling an actuator by adjusting the pressure in each of the pressure chambers of an actuator made of a cylindrical elastic body whose interior is separated into a plurality of pressure chambers by a partition wall, comprising:
In order to detect the deformation state of the actuator, at least one of the pressure chambers is provided with means for detecting the pressure of the pressure chamber and means for detecting the volume of the pressure chamber. Control device. 2. An actuator control device that controls the actuator by adjusting the pressure of each pressure chamber of the actuator, which is made of a cylindrical elastic body whose interior is separated into a plurality of pressure chambers by a partition wall,
For at least one of the pressure chambers, a deformation state of the actuator is detected using means for detecting the pressure in the pressure chamber, means for detecting the volume of the pressure chamber, and the pressure and volume obtained from these means. 1. An actuator control device comprising: means for controlling an actuator. 3. A volume chamber connected to the pressure chamber is provided,
3. The actuator control device according to claim 1, wherein the volume of said pressure chamber is detected by detecting the volume of said volume chamber.