JPS5953192A - Robot - 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) Technical Field of the Invention The present invention relates to an industrial robot, and particularly to an improvement in the connecting portion (wrist portion) between an arm and a hand.

(2) Background of the technology In recent years, industrial robots have been introduced on factory assembly lines to automate the manufacturing of various products. When using such an industrial robot to perform fitting work for a fitter who inserts a member into a hole, it is necessary to align the fitting parts with each other in the fitting work where the fitting tolerance is highly accurate in microns. If this is not done correctly, the insertion process may not be carried out smoothly and the component may be damaged. Therefore, there is a need for a robot that can easily control positioning in order to smoothly accomplish high-precision fitting work.

(3) Prior art and problems Conventionally used robots for fitting work have a hand at the tip of the arm that grasps the component to be inserted, and by horizontally moving the arm, the robot positions the component over the hole to be inserted, and then the arm The member is fitted into the hole by vertical movement of the member. In conventional robots, the hand is rigidly fixed to the tip of the arm, and if the positions of the parts to be fitted are even slightly misaligned, insertion is difficult, and the parts are rarely damaged. Therefore, a highly accurate control mechanism is required to control the positioning of the arm, making the robot expensive.

(4) Purpose of the Invention The present invention has been made in view of the above-mentioned drawbacks of the prior art, and allows the fitting work to be easily and reliably achieved without requiring highly precise control for positioning the fitting. The aim is to provide inexpensive robots.

(5) Structure of the Invention In order to achieve this object, in the present invention, in a robot consisting of a hand for grasping an object and an arm for moving the hand, a displacement is made in a direction orthogonal to each other at a connecting portion between the arm and the hand. A wrist consisting of a parallel spring assembly consisting of two possible sets of parallel leaf springs, the upper ends of each set of parallel leaf springs being fixed to a common mounting base, and the lower ends of each set of parallel leaf springs being fixed to separate mounting bases. The parallel spring assembly has a limit means for regulating the displacement of the parallel leaf spring.

(6) Embodiment of the Invention FIG. 1 is a perspective view of an example of a wrist of a robot according to the present invention. The wrist 1 has parallel leaf springs 3a, 3 that can be displaced in the X direction.
b and parallel plate springs 4a and 4b that can be displaced in the Y direction orthogonal to the X direction.

The upper end of each parallel leaf spring 3a, 3b, 4a, 4b is removably fixed to each side of the square common mounting base 2 with screws 10. The lower ends of the X-direction parallel leaf springs 3a, 3b are fixed to the mounting base 6 with screws 10, and the Y-direction parallel leaf springs 4B
, 4b are fixed to another mounting base 5 by screws 10. A connecting rod 7 with an arm (not shown) located above the wrist 1 is fixed to the lower end mounting base 5 of the parallel plate springs 4a, 4b in the Y direction, and this connecting rod 7 is connected to the parallel plate springs 3m, 3b,
4m and 4b are connected to the arm through the through hole 8 of the common mounting base 2 at the upper end. 9 is a screw hole for connection with the arm. X-direction leaf springs 3a, 3b and Y-direction leaf spring 4a
, 4b are fastened to each mounting base 2, 5.6 by screws 10 in order to obtain an arbitrary spring constant by replacing them. When a force F is applied to the connecting rod 7 between the wrist and the arm, the parallel leaf spring 3a in the X direction is activated according to the force Px and Py.

3b and the parallel plate springs 4m and 4b in the Y direction deform to absorb this side F. In this case, since the movable range of the connecting rod 7 is determined by the diameter of the through hole 8, the displacement of the parallel plate spring is regulated by the through hole 8.

FIG. 2 is a perspective view of another example of the wrist 1 according to the present invention.

In this example, each parallel leaf spring 3a.

The lower end mounts 6, 5 of 3b, 4m, 4b are U-shaped as shown in FIG. 3, and have U-shaped recesses 6a, 5a, respectively. The mounts 5 and 6 are arranged so that their recesses face each other and are orthogonal to each other so that each mount fits into the recess of the other mount. The movable range of each mount in the x and X directions is determined by the difference between the width W1 of the concave portion of each mount and the width W2 of the mating mount inserted therein, and the displacement of the parallel leaf spring is regulated. In this example, each parallel leaf spring 3a, 3b
, 4a, 4b have the same lengths Lx and L7. Therefore 1
Depending on the type of spring shape, the same spring constant can be obtained in the X and Y directions. The other configurations and operations are the same as those in the example shown in FIG.

FIG. 4 is a perspective view of still another example of the wrist 1 according to the present invention. In this example, the X direction parallel plate springs 3m, 3b
Length Lx and Y direction parallel leaf spring 4a.

In order to equalize the length L7 of 4b, the mounting position of the common mounting base 2 is stepped in the X direction and the Y direction. The other configurations and operations are the same as those in the example shown in FIG.

FIG. 5 shows an example of a robot 140 using a wrist 1 made of such a parallel spring assembly. Arm 15 and hand 1
A wrist 1 is provided between 6 and 6. The arm 15 can be rotated forward and backward as shown by the arrow E, and can be expanded and contracted as shown by the arrow F, and the hand 16 grasps the round bar 17 at a predetermined location and inserts it into the hole 19 of the member 18 into which it is to be inserted. move it to the upper position,
Then, by vertical displacement of the arm 15 in the direction of arrow G, the round bar 1
7 into the hole 19. A chamfer 20 consisting of a tapered surface is provided on the artificial periphery of the hole 19. Round bar 17 and hole 1
9 is misaligned within the range of the chamfer 20 (FIG. 6), when the arm 15 is lowered, the round bar 17 comes into contact with the tapered surface of the chamfer 20. When the arm 15 is further lowered, a force is applied to the round bar 17 in the H direction, and in response, a force is applied to the wrist 1 in the horizontal direction in the X direction and the Y direction depending on the position of the wrist 1. Therefore, each parallel plate spring of the wrist 1 is displaced in the X direction and the Y direction, and the round bar 17 slides on the tapered surface of the chamfer 20 and fits into the hole 19 as shown in FIG. In addition, in FIG. 7, only the displacement in the X direction is illustrated.

FIG. 8 is a perspective view of still another example of the wrist of the robot according to the present invention. Parallel leaf springs 3m and 3b for the wrist in the above example
, 4a, 4b is provided with a cross spring 21 consisting of plate springs 22, 23 forming a cross at the lower part of the parallel spring assembly, and a hand (not shown) is connected via this cross spring 21. This cross spring 21 is caused by bending deformation of the leaf spring 22 and 23
The axis of the wrist 1 can be angularly displaced around the X-axis in the α direction by the torsional deformation of , and can be angularly displaced around the Y-axis in the β direction by the bending deformation of the leaf spring 23 and the torsional deformation of the leaf spring 22. ,
Furthermore, it can be displaced in two directions orthogonal to the x and X directions. Since the parallel spring assembly can be displaced in two directions, X and Y, the wrist, which is a combination of the parallel spring assembly and the cross spring, constitutes a compliance mechanism with five degrees of freedom. Detailed views of the lower end of such a wrist are shown in FIGS. 9 and 10. As mentioned above, a U-shaped recess is formed in both mounting bases 5 and 6 at the lower end of the parallel (υ spring assembly), and the width of the parallel (υ) spring assembly is determined by the difference between the width of this recess and the width of the mating mounting base that fits into the The movable range of the hand in the X direction and Y direction (Sx+S
)') is determined. Further, the vertical gap 27 between the mounting bases 5 and 6 determines the two-direction movable range (Sz) of the hand relative to the arm.

A force detector such as a strain gauge is affixed to each leaf spring that makes up this flexible 5-freedom displaceable wrist, and the output of this strain gauge is used to detect force and displacement in each direction.
That is, the position of the robot can be feedback-controlled in accordance with the positional deviation and angular deviation of the robot's hand. It is desirable to attach the strain gauge to the maximum deformation position of each leaf spring, and the strain gauge should be attached to the parallel leaf springs 3a and 3b in the X direction and the Y direction.
, 4m and 4b, strain gauges 24 are attached to the upper and lower ends of each leaf spring as shown in FIGS. 11 and 12, and strain gauges 24 are attached to the cross spring 21 as shown in FIG. 24 is pasted near the center of each leaf spring 22 and 23 forming a cross.

(7) As described in detail, in the present invention, the wrist of the mechanical compliance mechanism is provided at the connection part between the arm and hand of the robot to enable displacement such as positional and angular displacement of the hand with respect to the arm. As a result, when performing fitting work, smooth fitting work can be achieved even if fitting positioning control is rough, without using a high-precision and expensive positioning control mechanism, and it is possible to achieve smooth fitting work even if the fitting positioning control is rough. Damage to the component is prevented. Also, x, y of each leaf spring that makes up the wrist.
, has a means for regulating the amount of displacement in the β direction, thereby preventing damage to the leaf spring due to buckling stress in the event of excessive displacement, and providing a highly reliable compliance function.

[Brief explanation of the drawing]

1 and 2 are perspective views of different examples of the wrist of the robot according to the present invention, and FIG. 3 is a partial detailed view of the wrist of FIG.
FIG. 4 is a perspective view of another example of the robot wrist according to the present invention, FIG. 5 is a perspective view of an example of the mouth pot according to the present invention, and FIG.
7 and 7 are respectively sectional views showing the fitting operation state of the robot according to the present invention, FIG. 8 is a perspective view of still another example of the wrist of the robot according to the present invention, and FIGS. 9 and 10 are FIG. 8 is a partial sectional view of the wrist in different directions, and FIGS. 11 to 13 are exploded perspective views showing the state in which strain gauges are attached to each leaf spring of the wrist shown in FIG. 8. 1...Wrist, 2...Common mounting base, 3a, 3b,
4a, 4b...Parallel leaf spring, 5,6...Mounting base,
7... Connecting rod, 8... Shell through hole, 5a, 6a... Recessed portion. Patent applicant Fujitsu Ltd. Patent agent Akira Aoki Patent attorney Kazuyuki Nishidate Patent attorney Yukio Uchida Patent attorney Akiyuki Yamaguchi (II) Figure 2 b Figure 6 15 Figure 7 5 Figure 10 Atsushi 13

Claims (1)

[Scope of Claims] 1. In a robot consisting of a handle for grasping an object and an arm for moving the handle, there is provided at the joint between the arm and the hand, 2 movable in mutually orthogonal directions. A wrist consisting of a parallel spring assembly consisting of silk parallel leaf springs, the upper end of each set of parallel leaf springs being fixed to a common mounting base, and the lower end of each set of parallel leaf springs being fixed to a separate mounting base; A robot characterized in that the parallel spring assembly has a glue mint means for regulating displacement of the parallel leaf spring. 2. In the robot according to claim 1, a connecting rod with the arm is fixed to the lower end mounting base of one set of parallel plate springs, and the connecting rod is passed through the common mounting base to the upper end of the parallel plate spring. The limit means is configured by connecting the arm and the wrist by fixing it to the arm, and determining the movable range of the connecting rod by the gap between the inner surface of the connecting rod through hole provided in the common mounting base and the outer surface of the connecting rod. A robot that is characterized by: 3. In the robot according to claim 1, each set of parallel spring assemblies has a U-shaped inner recess in the lower end mounting base, and the recesses of each mounting base face each other, and each mounting base is connected to the other side. The movable range of each mounting base within the recess is determined by the difference between the width of the recess and the width of the other mounting base that fits into the recess. A robot comprising the limit means described above. 4. The robot according to claim 1, wherein the parallel plate spring is detachably attached to the mounting base.