JPS6141716B2 - - Google Patents

Description

[Detailed description of the invention] Technical field of invention The present invention relates to a joint such as a manipulator.

Prior Art and Problems Shoulder, upper arm, forearm, hand or lower back, thigh, buttock, foot, or other adjacent parts of manipulators, industrial robots, prosthetic arms or legs, and other devices with joint construction mechanisms (hereinafter referred to as "manipulators, etc.") A joint that connects aggregates with relative mobility has two degrees of freedom that allow one joint to move in two axes perpendicular to the other aggregate. This is desirable.

Conventionally, in manipulators, etc., there are linear joints that move adjacent aggregates toward and away from each other on the same axis, rotational joints that rotate adjacent aggregates relatively around the same axis, and adjacent aggregates. The desired degree of freedom is obtained by appropriately combining the three pivot joints that rotate relative to one axis around an axis perpendicular to one of the aggregates.

However, in conventional manipulators, etc., there is one degree of freedom with only one joint interposed between adjacent aggregates, so a translational joint and a rotary joint are attached to both ends of one aggregate. In this case, there is a problem that the length of the aggregate must be increased, and when using a swivel joint, the actuator of the raft protrudes perpendicularly to the longitudinal direction of the aggregate, so the length of the aggregate must be increased. There is a problem in that the outer diameter of the part becomes large.

In addition, in order to have two degrees of freedom in one joint,
When combining a prismatic joint or a rotary joint with a swivel joint to form a compound joint, the structure becomes complicated, and the actuator of the swivel joint protrudes in a direction perpendicular to the longitudinal direction of the aggregate. There are problems such as the external dimensions of the joint itself becoming larger.

OBJECTS OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a joint such as a manipulator that has multiple degrees of freedom as a single unit.

Structure of the Invention In order to achieve the above object, the present invention connects one end of a guide rod attached to a first aggregate and a second aggregate so as to be able to move relatively swivelly, and connects a first movable body to the guide rod. and a second movable body is movably mounted, the first and second movable bodies are operatively connected to a drive device mounted on the second aggregate, and one end of the first link is pivotally connected to the first movable body. At the same time, this first
The other end of the link is connected to allow free swivel movement relative to the first aggregate, one end of the second link is pivotally connected to the second moving body, and the other end of the second link is connected to the guide rod and the second link. The first aggregate is positioned in a plane perpendicular to the plane formed by the first link and connected to allow free swivel movement relative to the first aggregate, and the first aggregate and the second aggregate are connected with two degrees of freedom. This is how it was done.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 and 2 are front and side views showing a first embodiment of the present invention. In the joint of this embodiment, a first aggregate 1 in the form of a plate and a second aggregate in the form of a rectangular plate are shown in FIGS.
One end (the upper end in each figure) of the ball screw 3 attached to the aggregate 2 can be relatively swiveled (3 degrees of freedom) using a ball joint 4 or a universal joint.
).

The ball screw 3 increases the transmission efficiency of the rotational drive device, which will be described later, and serves as a guide rod for guiding the first and second movable bodies, which will be described later, that reciprocate on the same straight line, and connects both ends of the second aggregate 2. It is fixedly supported on the second aggregate 2 in parallel with one of the plate surfaces (on the right side in FIG. 2) via brackets 5, 5 fixed near the section. A cylindrical first nut member 6 and a second nut member 7 are screwed onto the ball screw 3.
A cylindrical first moving body 8 and a second moving body 9 are rotatably fitted on the outer periphery of each nut member 6, 7 via a plurality of bearing members 10 such as radial ball bearings.

Each of the movable bodies 8 and 9 is rotated by a shaft as the first and second nut members 6 and 7 are rotated in the axial direction along the ball screw 3 through a rotation drive device and a rotation transmission mechanism that will be described later. The pins 8a and 9a are provided at symmetrical positions on the respective outer peripheries and protrude in the radial direction (in the left-right direction in FIGS. 1 and 2).

A first link 11 is pivotally connected to the first movable body 8 by engaging a pin portion 8a with a hole at the end of a forked connecting portion 11a provided at one end of the first link 11. The other end is the first aggregate 1 and the ball joint 1
2 for relative swivel movement.

Further, a second link 13 is pivotally connected to the second movable body 9 by engaging a pin portion 9a with a hole at the end of a forked connecting portion 13a provided at one end of the second link 13. The other end of the link 13 is connected to the ball screw 3 and the first link 1.
1, and is connected to the first aggregate 1 via a ball joint 14 so as to be able to freely swivel relative to the first aggregate 1.

A circular plate-shaped spur gear 15 having an outer diameter suitably larger than that of the first nut member 6 is connected to one end (the lower end in FIGS. 1 and 2) of the first nut member 6. The spur gear 15 constitutes a part of a first rotation transmission mechanism 16 that transmits the rotational force of a rotation drive device to be described later to the first nut member 6, and is arranged with its axis parallel to the ball screw 23. The main driving gear 17 is supported at one end by a bearing bracket 18 fixed to the second aggregate 2, and the other end is supported by a bearing bracket 18 fixed to the second aggregate 2. The output shaft 19a of a rotary drive device 19 such as a reversely rotatable electric motor is suitably interlocked and connected.

Further, at one end of the second nut member 7, as in the case of the first nut member 6, a circular plate-shaped spur gear 20 having an outer diameter suitably larger than that of the second nut member 7 is connected. be. The spur gear 20 constitutes a part of the second rotation transmission mechanism 21 and has an axis parallel to the ball screw 3 and a point on the axis of the ball screw 3 as a point of symmetry of the first rotation transmission mechanism 16. Source gear 1
It meshes with a relatively long source drive gear 22 arranged symmetrically with 7.

The source gear 17 has one end supported by a bearing bracket 23 fixed to the second aggregate 2, and the other end connected to an output shaft 24a of a rotary drive device 24 such as an electric motor capable of forward and reverse rotation as appropriate. are linked together.

Next, the action of the joints having the above structure will be explained using FIGS. 3a and 3b, FIGS. 4 and 5.

Now, in order to fix the first aggregate 1 and move the second aggregate 2 within the plane where its plate surface exists (hereinafter referred to as "X-Z plane"), the rotation drive device 1
9 in an appropriate direction, the first rotation transmission mechanism 16
The first moving body 8 is rotated through the first nut member 6.
is moved, for example, from the position shown by the solid line in FIG. 3a to the position shown by the two-dot chain line.

Due to the above movement of the first moving body 8, the ball screw 3
In this case, the first aggregate 1 and the first moving body 8 are connected to the first link 1
1, it is tilted at a predetermined angle θ ₁ from the vertical position with the center A of the ball joint 4 at one end as the center.

In addition, in order to move the second aggregate 2 in a plane perpendicular to the plane where the plate surface exists (hereinafter referred to as "X-Y plane"), the same steps as in the case of movement in the X-Z plane are performed. , by rotating the second nut member 7 via the rotation drive device 24 and the second rotation transmission mechanism 21 and moving the second moving body 9.

In addition, in order to fix the first aggregate 1 and move the second aggregate 2 spatially, each rotation drive device 19, 24 is operated appropriately, and the first and second rotation transmission mechanisms 16, 2
This is accomplished by rotating the first and second nut members 6 and 7 through the nut member 1 and moving the first and second moving bodies 8 and 9.

Here, let L be the movement distance of the first moving body 8 due to the movement of the second aggregate 2 in the X-Z plane, and the center A of the ball joint 4 at one end of the ball screw 3,
The center B of the ball joint 12 at the other end of the first link 11 and the first moving body 8 at one end of the first link 11
In △ABD whose apex is the pivot point D with
a, = b, and the center A and the first pivot point D
If the distance between the two is Y ₀ and ∠BAD=θ ₀ , then the following relationship exists between the moving iron distance L and the angle θ ₁ , etc.

θ ₀ =cos ^-1 a ² +Y ₀ ² -b ² /2Y ₀ a……
...(1) For a change in angle θ ₁ , θ ₀ + θ ₁ = cos ^-1 a ² + (Y ₀ -L) ² - b ² /2
(Y ₀ −L)a……………… (2) Therefore, θ ₁ = cos ⁻¹ {a ² +(Y ₀ −L) ² −b ² /2(Y
₀ −L)a} −cos ⁻¹ (a ² +Y ₀ ² −b ² /2Y ₀ a)…
…(3) becomes. Since a and b are known structurally, the angle θ
The relationship between the change in ₁ and the moving distance is an inverse cosine relationship, as shown in FIG.

In addition, the force U at the other end of the ball screw 3 is, as shown in FIG. ………(4) is obtained. Here, W is a force in the axial direction of the first moving body 8 and is a force transmitted from the rotational drive device 19.

Therefore, in order to increase the force U,
Either the interval Yo may be increased so that the value of Yo/Ye approaches "1", or the driving force of the rotary drive device 19 may be increased.

Furthermore, the position {P(x, y, z)} of the other end P of the ball screw 3 in the space is, as shown in FIG.
Yo and the second link 13 of the center A and the second moving body 9
It is determined by controlling the distance between one end of the pivot point E and the pivot point E.

Note that the ball screw 3 is connected to the first and second links 1.
1 and 13, that is, has a so-called firm structure, a large external force can be applied to the other end P. Further, in FIG. 5, C is the center of the ball joint 14 at the other end of the second link 13.

FIG. 6 is a front view showing a second embodiment of the present invention, in which the joints of this embodiment are the same as those of the first embodiment. The two nut members 6 and 7 are rotated by the rotation drive devices 19 and 24 and the first and second rotation transmission mechanisms 16 and 21, whereas the rotation of the ball screw causes the first and second nut members to be rotated through the nut members. The difference is that two moving bodies are moved.

In the following description, members having the same functions as those shown in FIGS. 1 and 2 will be denoted by the same reference numerals, and the description thereof will be omitted.

That is, the ball screw 3 is rotatably supported by the second aggregate 2 via brackets 5, 5, and has one end connected to the first aggregate 1 via a ball joint 4 so as to be able to freely swivel relative to the first aggregate. screw 3a
and a second screw 3b positioned on the same straight line as the first screw 3a and rotatably supported on the second aggregate 2 via brackets 5, 5.

First and second nut members 6 and 7 are screwed into each screw 3a and 3b, and each nut member 6 and 7 is pivotally connected to one end of the first and second links 11 and 13. The first and second movable bodies 8 and 9 are rotatably fitted through bearing members (not shown).

Further, spur gears 15 and 20 are fixed to one end of each of the screws 3a and 3b. The respective spur gears 15 and 20 are connected to the first and second rotation transmission mechanisms 1
6, 21, and meshes with the source pinions 25, 26, and each source pinion 2
5 and 26 are fixed to output shafts 19a and 24a of rotary drive devices 19 and 24 fixed to the second aggregate 2, respectively.

Therefore, by the operation of each rotation drive device 19, 24, the first screw 3a and the second screw 3b are
The rotation of the screws 3a and 3b causes the first and second movable bodies 8 and 9 to rotate through the second rotation transmission mechanisms 16 and 21, and the first and second moving bodies 8 and 9 are rotated by the action of the first and second nut members 6 and 7. By moving along 3a and 3b, the second aggregate 2 moves in two axial directions perpendicular to the first aggregate 1. Therefore, the other end of the second aggregate 2 moves within a spherical surface centered on the center A of the ball joint 4.

Note that the embodiments of the present invention are not limited to the above-mentioned embodiments, but the present invention includes various embodiments described below.

(1) The first and second aggregates 1 and 2 are rod-shaped or cylindrical, and these shapes are appropriately combined.

(2) The ball screw 3 that guides the first and second movable bodies 8 and 9 is rotatably installed in a long hole provided on the axis of the second aggregate 2.

(3) A member that guides the first and second movable bodies 8 and 9,
Use rod or spline.

(4) The first and second moving bodies 8 and 9 are formed into a block shape.

(5) a rotation transmission mechanism 16 that transmits the rotational force of the rotational drive device to move the first and second moving bodies 8 and 9;
21 is composed of a worm and a worm wheel.

(6) The drive device for moving the first and second movable bodies 8 and 9 is a linear motor or a fluid pressure reciprocating drive device such as a hydraulic cylinder, a pneumatic cylinder, or a hydraulic cylinder.

(7) Use one rotary drive device and output via a clutch, transmission, etc.

(8) Attach the rotation drive devices 19 and 24 to both sides of the second aggregate 2.

(9) The lengths of the first and second links 11 and 13 are adjustable.

Application Examples Figures 7, 8, and 9 are skeleton diagrams showing application examples of the present invention. It shows the case where it is used as a joint between the hip and thigh of a robot or a prosthetic leg, etc., and FIG. The case where it is used as a joint between adjacent arms is shown.

When the shoulder is used as a prosthetic hand joint, the transmission force is maximum when the upper arm is horizontal (when the upper arm is raised forward at 90 degrees), so ∠ABD=∠
If ACE = 90°, the most efficient force transmission can be achieved.

In addition, when used as a joint in a walking robot, etc., the thigh's vertical movement (Z direction) and horizontal movement (x
directions) can be easily obtained.

Furthermore, when used as a joint of a multi-jointed robot, by connecting adjacent arms, etc.
A multi-jointed robot like an elephant's trunk can be constructed, and by using a ball screw as the guide rod,
It is possible to reduce the load on the motor to about 1/2 to 1/3 times that of conventional motors. Furthermore, by combining joint movements in the y and z directions instead of only in the x and z directions, the work area of the manipulator or the like can be further expanded.

Effects of the Invention As described above, the present invention provides the following various effects compared to the conventional technology.

(1) The structure can be simplified.

(2) One joint can have two degrees of freedom.

(3) Despite having two degrees of freedom, the whole can be made smart and compact.

[Brief explanation of the drawing]

1 and 2 are front and side views showing the first embodiment of the present invention, FIGS. 3a, b, 4 and 5 are explanatory diagrams of the operation of the joints of the first embodiment, respectively,
FIG. 6 is a front view showing the second embodiment of the present invention, and FIG.
8 and 9 are skeleton diagrams showing application examples of the present invention, respectively. 1...First aggregate, 2...Second aggregate, 3...Ball screw (guide rod), 4...Ball joint,
8...first moving body, 9...second moving body, 11...
1st link, 12...Ball joint, 13...
...Second link, 14...Ball joint, 16
...first rotation transmission mechanism, 19...rotation drive device,
21... Second rotation transmission mechanism, 24... Rotation drive device.

Claims (1)

[Claims] 1. One end of a guide rod attached to a first aggregate and a second aggregate is connected so as to be movable relative to each other, and a first movable body and a second movable body are movably attached to the guide rod, and These first and second movable bodies are interlocked and connected to a drive device attached to the second aggregate,
One end of the first link is pivotally connected to the first movable body, and the other end of the first link is connected to allow free swivel movement relative to the first aggregate, and the second link is pivotally connected to the second movable body. One end of the second link is pivotally connected, and the other end of the second link is positioned in a plane perpendicular to the plane formed by the guide rod and the first link, and connected to allow free swivel movement relative to the first aggregate. A joint such as a manipulator characterized by.