JPH06190764A - Gripping mechanism - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a gripping mechanism capable of accurately gripping objects having various shapes and sizes from any direction. [Structure] Cylinder rod 1 consisting of multiple cylinders
Fluid pressure movable means arranged so that the tips of 0 and 18 are in contact with the object, fluid pressure detection means for detecting the fluid pressure in the cylinder of the fluid pressure movable means, and fluid pressure in the cylinder of the fluid pressure movable means. And a fluid pressure calculating means for calculating a command value for inputting the fluid pressure detected by the fluid pressure detecting means and outputting the fluid pressure to the fluid pressure adjusting means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manipulator, and in particular, it can grasp objects of various shapes and sizes at a site such as nuclear power or space where humans cannot easily approach it or a fully automatic factory. The present invention relates to a gripping mechanism suitable for.

[0002]

2. Description of the Related Art Conventionally, as described in Japanese Unexamined Patent Publication No. 62-152690, there has been one in which a work holding member is made of a shape memory alloy so that a single holder can hold various shaped works. is there.

[0003]

In the above-mentioned prior art, when holding a work of a certain shape, it is necessary to heat and shape the shape memory alloy so as to follow the shape of the work each time, and prompt treatment is required. Was not suitable at the work site.

An object of the present invention is to provide a gripping mechanism capable of accurately gripping objects of various shapes and sizes from any direction.

[0005]

In order to achieve the above object, the present invention provides a fluid pressure movable means which is composed of a plurality of cylinders and is arranged so that the tip of a cylinder rod and an object are in contact with each other. The fluid pressure detecting means for detecting the fluid pressure in the cylinder of the means, the fluid pressure adjusting means for adjusting the fluid pressure in the cylinder of the fluid pressure moving means, and the fluid pressure detected by the fluid pressure detecting means are input. And a fluid pressure calculating means for calculating a command value to be output to the fluid pressure adjusting means.

[0006]

[Function] A fluid such as oil is injected into the fluid pressure movable means, and even if the tips of the plurality of cylinder rods are shaped into uniform shapes by the opening and closing of the parallel hand, the objects can have any uniform pressure. Contact. At the same time when the gripping force is detected, the operation of the parallel hand is stopped, and the fluid pressure adjusting means is operated to push the cylinder rod. As a result, the other cylinder rod is pushed out by the oil. Then, the pressure is applied to the fluid pressure detecting means, the operation of the cylinder rod is completed, the holding force of the parallel hand and the value of the fluid pressure detecting means are calculated by the fluid pressure calculating means, and the fluid pressure adjusting means is adjusted until they become equal. Activate. When the values are equal, the cylinder rod is reliably gripped in a state that follows the shape of the object.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.
Will be described. As shown in FIG. 1, the manipulator 1
A parallel hand 5 having a function of operating the pair of parallel grippers 4 from the gripper support portion 2 through the pair of parallel link mechanisms 3 so that the opposing gripping surfaces are always parallel to each other is attached to the tip end of the. ing. A force sensor 7 for detecting the driving force of the gripper, that is, the gripping force, is built in the connecting portion between the parallel link mechanism 3 and the gripper driving mechanism 6 including the ball screw 6a for opening and closing the parallel gripper 4 and the gripper driving motor 6b. Has been done. Gripper drive motor 6b
Has an encoder 8 for detecting the rotation angle. Further, as shown in FIG. 2, a hydraulic cylinder mechanism 9 having a plurality of cylinder groups and in which oil is injected is arranged in the grip portion of the parallel gripper 4. Each cylinder of the hydraulic cylinder mechanism 9 has the same size and the same structure. That is, each cylinder has the same inner diameter and the stroke of the cylinder rod 10. A circular plate 13 rotatably held by a pin joint 12 is provided at the tip of the cylinder rod 10 that is movable in the central axis direction along the inner surface of the cylinder 11. As shown in FIG. 3, the insertion portion of the cylinder 11 and the cylinder rod 10 has a triple packing V packing 14 and packing presser 15 for preventing oil from leaking from the cylinder 11 to the outside. At the end of the hydraulic cylinder mechanism 9, there is a pressure adjusting mechanism 16 for uniformly maintaining the negative pressure of each cylinder of the hydraulic cylinder mechanism 9 and adjusting the pressure applied to each cylinder rod. As shown in FIG. 4, the pressure adjusting mechanism 16 includes a pressure adjusting motor 19 that presses a cylinder rod 18 that can move in the central axis direction along the inner surface of a cylinder 17, and gears 20a, gears 20b, ball screws that are transmission parts thereof. 20c and a semiconductor pressure sensor 21 that detects the internal pressure of the hydraulic cylinder mechanism 9. Next, the control device according to the present invention will be described with reference to FIGS. The grasping force of the grasped object grasped by the parallel gripper 4 is obtained by converting the analog signals of the force sensor 7 and the semiconductor pressure sensor 21 into the AD converter 5.
It is converted into a digital signal by 0 and taken into the microcomputer 51. By making the values of the force sensor 7 and the semiconductor pressure sensor 21 equal, a reliable gripping operation is performed. Therefore, the gripper driving motor 6b
A command value is given to the motor drivers 52 and 53 that drive the pressure adjusting motor 19 via the DA converter 54 that converts the signal from the microcomputer 51 into an analog signal.

Next, the gripping operation will be described in the case where the object to be gripped 30 has a cylindrical shape as shown in FIG. The oil inside the hydraulic cylinder mechanism 9 is at the position where the cylinder rod 18 is pushed in,
That is, at the lower limit position, the cylinder rod 10 is entirely injected with the amount to be extruded. Therefore, at the position where the cylinder rod 18 is pushed out, that is, at the upper limit position, all the cylinder rods 10 are in a state capable of contracting. In this state, first, the parallel gripper 4 is moved toward the object to be grasped 30 by the operation of the parallel link mechanism 3. Then, the plate 13 of the cylinder rod 10
Contacts the object to be grasped 30. After that, when the parallel gripper 4 is closed, the gripping force is detected by the force sensor 7. At the same time when the gripping force is detected, the operation of the parallel gripper 4 is stopped, and the pressure adjusting motor 19 is operated to push the cylinder rod 18 in. Along with that, the cylinder rod 10 is also pushed out by the oil. Then, the semiconductor pressure sensor 21
Then, pressure is applied to the cylinder rod 10, the operation of the cylinder rod 10 is completed, and the pressure adjusting motor 19 is operated until the gripping force of the force sensor 7 and the value of the semiconductor pressure sensor 21 become equal. When the values are equal, the cylinder rod 10 is reliably gripped in the state of following the shape of the object to be gripped 30. This is because the thrust force F of the cylinder is determined by the pressure p of the system and the pressure receiving area A of the piston, and is represented by the relation F = pA. This relationship is the same as in the case of pneumatic pressure, but since oil is not compressible, the oil supplied to the cylinder is consumed only to move the piston, and when the cylinder rod 18 is pushed in, the thrust of the cylinder is increased. F is generated to generate a pressure of p = F / A. Then, the cylinder rod 10 is pushed out to consume the generated pressure. That is, since the volume V of the oil supplied into the cylinder is about to be kept constant, the thrust F of the cylinder is not generated, that is, the cylinder rod 10 is in contact with the object to be grasped 30 or is fully extended. In this state, the uniform pressure applied to the semiconductor pressure sensor 21 is applied to the cylinder rod 10.

[0009]

According to the present invention, objects of various shapes and sizes can be properly grasped from any direction.

[Brief description of drawings]

FIG. 1 is an overall block diagram of the present invention.

FIG. 2 is an explanatory diagram of a hydraulic cylinder mechanism.

FIG. 3 is a partial explanatory view of a hydraulic cylinder mechanism.

FIG. 4 is an explanatory view of a pressure adjusting mechanism.

[Explanation of symbols]

4 ... Parallel gripper, 9 ... Hydraulic cylinder mechanism, 10, 18
... cylinder rod, 16 ... pressure adjusting mechanism, 21 ... semiconductor pressure sensor, 51 ... microcomputer.

Claims (1)

[Claims] 1. A gripping mechanism having a pair of parallel-movable fingers provided on a hand portion attached to the tip of a manipulator, wherein a facing surface portion of the fingers comprises a plurality of cylinders and a tip of a cylinder rod and an object. Fluid pressure movable means arranged so as to contact an object, fluid pressure detection means for detecting the fluid pressure in the cylinder of the fluid pressure movable means,
A fluid pressure adjusting means for adjusting the fluid pressure in the cylinder of the fluid pressure moving means, and a command value for inputting the fluid pressure detected by the fluid pressure detecting means and outputting it to the fluid pressure adjusting means are calculated. A gripping mechanism comprising: a fluid pressure calculating means.