JPS60249588A - Positioning mechanism - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Industrial Application Field The present invention provides a method for placing a table on which a desired article is placed or fixed at any position and angle within a space. It relates to a mechanism for moving and holding it in that state.

(2) Conventional technology Conventional industrial robot arms include rectangular coordinate types, cylindrical coordinate types, polar coordinate types, indirect types, etc. All of these have a wide range of motion and are highly accurate positioning mechanisms. Are known. Furthermore, there are 4 to 6 degrees of freedom, and most required movements can be realized functionally.

(3) Problems to be solved by the invention □ In the conventional positioning mechanism as described above, in order to perform a certain operation, all actuators must be driven, except in special cases, even when the moving distance is small. Must be controlled.

Furthermore, the weight of the actuator at the tip serves as a load on the actuator at the base, resulting in large energy consumption.

In an operation in which the moving distance is small and drive control of all actuators is required, most of the moving time is the time required for rising and falling, resulting in a problem that the moving time becomes longer.

(4) Means for Solving the Problems In order to solve the problems of the prior art as described above, the present invention provides three gear mounting plates each mounted on supports provided at three points of an appropriate support member. Both ends are rotatably supported, a spur gear is fixed to each gear mounting plate, and two links are rotatably attached to the axis of the spur gear and the center shaft of the counter. A motor and a potentiometer having a pinion gear that meshes with the spur gear are fixed to each link, and one end of another link is rotatably connected to the outer end of each link. Each other end of each link is connected to three points on the table by a universal joint to form three sets of panda graphs, and a positioning mechanism that allows the table to be held at a constant angle and controlled. is attached to the tip of a rectangular coordinate type, cylindrical coordinate type, polar coordinate type, articulated type, etc. robot arm.

(5) Function As described above, this invention has a six-degree-of-freedom positioning mechanism attached to the tip of a robot arm such as a rectangular coordinate type, cylindrical coordinate type, polar coordinate type, or articulated type. When a measurement probe is fixed on the table of the mechanism to perform various automatic measurements, when assembly parts are placed on the table and various automatic assemblies are performed, or when an object gripping mechanism is attached to the table and the object is When used for handling, etc., the movement when the moving distance is long is performed by the robot arm, and when the moving distance is small, the movement is performed by the positioning mechanism.

(6) Example of implementation Figure 1 shows a Cartesian coordinate type robot arm, where 1 is a base, 2 is a column mounted on the base so as to move horizontally, and 3 is a robot arm that moves vertically up and down on this column. A second arm 4 is attached to the first arm so as to be able to move forward and backward, and a positioning mechanism 8 with six degrees of freedom is attached to the tip of this arm.

FIG. 2 shows a robot arm of the cylindrical coordinate type, in which the support 2 of the base 1 pivots around a vertical axis, and the support supports the first and second arms 3.4 and positioning as in FIG. A mechanism 8 is provided.

Fig. 3 shows a polar coordinate type robot arm, in which a first arm 3 is attached to a support 2 rotatably mounted on a base 1 so as to be movable up and down by a horizontal axis, and a second arm 4 is attached to the first arm. is attached so that it can move forward and backward, and the positioning mechanism 8 is provided at its tip in the same manner as described above.

The one shown in Fig. 4 is an articulated robot arm, in which a first arm 3, a second arm 4, and a third arm 5, which rotate around a horizontal axis, are attached to a pivoting support 2 provided on a base 1. A positioning mechanism 8 is provided at the tip of the third arm 5 with an axis orthogonal to the rotation axis of the third arm 5.

FIG. 5 shows the positioning mechanism 8 provided at the tip of the arm on each side. Reference numeral 11 denotes a support frame attached to the tip of the arm 4, etc., and supports 12 are provided on three sides of this support frame, respectively.
is fixed.

Reference numeral 13 denotes three gear mounting plates, and both ends of each mounting plate are attached to the 8 supports 12 so as to rotate around the F axis.

Further, a spur gear 14 is fixed to each of the mounting plates 13, respectively. E is a shaft fixed at the center of each spur gear 14,
Two links 15, 16 are mounted on each shaft for independent rotation.゛Each link
Motors 17 and 18 are fixed to 15 and 16 respectively,
A pinion gear fixed to the shaft of each motor is engaged with each spur gear 14. Furthermore, potentiometers 19 and 20 are fixed to each of the links 15 and 16, and a pinion gear fixed to the shaft of each potentiometer is engaged with each spur gear.

Moreover, the single parts of two separate links 21, 22 are rotatably connected to the outer ends of each link 15, 16 by an axis. The other end of each link 21, 22 is connected to a joint tool 23 by a shaft C. Reference numeral 24 designates a triangular table, each of which has a mouth-shaped joint holder 25 rotatably attached to the Δ axis.
(P) Each joint tool 23 is fitted into each joint holder, and is made rotatable by lll11B.

With this configuration, links 15, 16 and 21, 22 form a quadrilateral pantograph.

The axis A of this first positioning mWJ8 is parallel to the plane of the table 24, and the vertical axis B is parallel to the plane of the table. Also, axis C
is perpendicular to axis B, axis is parallel to axis C, axis F is parallel to axes C and D, and axis F is perpendicular to axis E.

Now, let us connect the axes E and C, and call the length of a line segment perpendicular to each the diagonal line length, and the angle between that line segment and the axis F the diagonal angle.

By applying current to the motors 17 and 18 to rotate their shafts, the angles of the links 15 and 16 with respect to the spur gear 14 can be changed, and the length and direction of the diagonals can be changed, respectively.

Further, the rotation angle of each link 15, 16 with respect to the spur gear 14 is measured by the rotation of the potentiometers 19 and 20.

By performing feedback control using the measurement results of each of the potentiometers 19 and 20 above, the length and direction of the diagonal can be freely and automatically controlled.

By the way, there are a total of six degrees of freedom in the position and direction of the table 1 in space. Therefore, in order to fix the table position and orientation, it is necessary to define and fix all six degrees of freedom.

Like ijR above, you can control the length and direction of the diagonal 4
If a part of the table is supported by a side link mechanism,
Since this part can be defined by two degrees of freedom, six degrees of freedom can be defined by supporting three points of the table using a similar link mechanism, so the position and direction of the table can be defined. is uniquely defined and fixed.

Therefore, if the table travels a long distance, each arm in each embodiment is moved using a known drive device or position detection device, and if the table travels a short distance, a total of six By measuring the angle of each two links using the potentiometers, and controlling the drive of each motor by feeding back the results, the table can be moved to any position and angle within a predetermined range, and the position can be adjusted. It is too difficult to support it at an angle.

In the case of the positioning mechanism of the embodiment, when an object is placed on the table with the table facing upward and the object is lifted upward, the gravity of the object rotates the lower link and raises the motor fixed to this link. However, the gravity acting on the motor itself is directed downward. Therefore, when viewed as a load on the motor, the force for holding an object is added to the motor's gravity, so with a small output motor,
Able to lift objects of relatively large weight.

(7) Effects (a) Since the positioning mechanism of the present invention is combined with a robot arm, operations that require a large movement distance are performed by the robot arm, and operations that require a small movement distance are performed by the positioning mechanism at the tip of the robot arm. Since this positioning mechanism is small and lightweight, high-speed operation is possible.

(b) When the moving distance is small, the use of a positioning mechanism allows operation with less energy consumption.

(c) Since the positioning mechanism includes many common parts, it is a 6-degree-of-freedom mechanism and is less expensive than the above mechanism. Therefore, by combining it with a simplified robot arm, a low-cost positioning mechanism can be realized.

[Brief explanation of drawings]

1 to 4 are perspective views of each embodiment of the present invention, and FIG. 5 is an enlarged perspective view of the positioning mechanism. 3...First arm 4...Second arm 5...Third
Arm 8...Positioning mechanism 12...Support 13
... Gear mounting plate 14 ... Spur gear 75.16, 21
．． 22...Link 17.18...Motor 19,2
0... Potentiometer 23... Joint tool 2
4...Table 25...Joint holder A, B, C, D, E, F...Shaft agent Patent attorney Kazu 1) Showa 1 diagram

Claims (1)

[Claims] Both ends of the three gear mounting plates are rotatably supported by supports provided at three points on a suitable support member, and a spur gear is fixed to each of the gear mounting plates. Two links are rotatably attached to the shaft center and the center shaft of the open base, and to each link, a motor and a potentiometer having a pinion gear that meshes with the spur gear are fixed, and the outer end of each link One end of each separate link is rotatably connected to each other, and each loose end of this separate link is
3 by connecting to 3 points on the table with a universal joint.
The positioning mechanism, which consists of a pair of pantographs and can hold and control the table at a fixed position and angle, can be attached to a robot arm of the rectangular coordinate type, cylindrical coordinate type, polar coordinate type, articulated type, etc. A positioning mechanism characterized by being attached to the tip of.