JPS6219394A - Drive for robot arm - 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 A.6 Field of the Invention The present invention generally relates to a robot arm driving device, and in particular,
This invention relates to a device for driving a robot arm connected to a book.

BACKGROUND OF THE INVENTION Mechanical robots are known in many fields for performing a variety of functions at multiple predetermined locations within their work envelope. In order to reach the desired position, the various robot arms must move through certain combinations of their allowed movement paths.

An example of such a motion is a motion performed by an articulated robot with articulated arms similar to a human arm. The first arm portion is pivotally connected at one end to the base of the robot for movement through a certain arc. The second arm portion is connected to the first arm portion at one end thereof.
is connected to the other end of the first arm portion for movement in a plane parallel to the first arm portion. A gripper or other tool handling element is attached to the other end of the second arm portion.

In most conventional robots, the movement of the first and second arm portions relative to each other and relative to the base is performed by two separate relatively large motors. The first motor is mounted on the base and is connected to the first motor via a transmission device.
□ Drive the first arm through the desired arc in the desired direction. A second motor, generally of the same size, is mounted on the first arm and coupled to the second arm via a transmission to drive the second arm through a desired arc and in a desired direction. do.

Requires large amounts of electricity. Second, and more importantly, because the second motor is placed on one of the robot arms, the first motor must move not only the robot arm but also the additional weight of the second motor. No.

SUMMARY OF THE INVENTION The object of the present invention is to provide an independent drive for the two parts of one robot arm, which uses less energy than conventional systems and which overcomes the drawbacks of the prior art. The goal is to provide the following.

According to the invention, therefore, an apparatus for driving a robot arm is provided that includes a variable cam mechanism and a cam follower coupled to the robot arm for driving the mouth arm.

According to a preferred embodiment of the invention, the variable cam mechanism comprises:
a base adapted for reciprocating linear motion, a cam arm pivotally connected to said base, and a screw device, such as a screw device, for pivoting the cam arm relative to the base to produce the desired movement of the cam follower. means.

Further 1--According to a preferred embodiment, said pivoting means are electronically controlled. Furthermore, - according to a preferred embodiment, the cam follower is connected to a rack fixed to the robot arm to be moved and arranged to mesh with nine gears.

Further, in accordance with the invention, there is provided an apparatus for driving at least two parts of one articulated robot arm, the apparatus comprising: a variable cam mechanism; and at least two cam followers; a robot arm portion connected to each of said robot arm portions.

- In accordance with a preferred embodiment, the variable cam mechanism includes at least two bases and at least two cam arms, each base and its respective cam arm □.

a cam arm connected to each base and a device for changing the angle between the cam arms, the device preferably including at least two small motors and two screw mechanisms; each is coupled to a respective one of the screw mechanisms for driving the screw.

20 DETAILED DESCRIPTION OF THE INVENTION Embodiments Referring to FIG. 1, there is shown a schematic diagram of a robot arm drive including a base 10 in accordance with the present invention. Base 10 is configured for constant amplitude reciprocating linear motion provided by any suitable device (not shown). A cam arm 12 is rotatably connected to the base 10. A device 14 is fixed to the base 10 and connected to the cam arm 12 for varying the angle θ between the base and the cam arm to provide a camming effect.

Device 14 may consist of any angle changing means, whether mechanical, electronic or any other means.

As illustrated in FIG. 1, the angle changing device 14 includes a relatively small motor 16 and a screw device 18 coupled to the rotor of the motor. Rotation of the screw device 18 causes a translational movement of the cam arm 12 along the length of the screw device 18, thereby changing the angle between the base 10 and the cam arm 12.

As a result of this angular change, the cam follower 20 can be moved along a continuously varying path.

One feature of the invention is that the end point of the cam follower is the same as its starting point, regardless of the change in angle between the base and the cam arm during the path or cycle traced by the cam follower. This is achieved by a constant amplitude of reciprocating movement of the base.

Thus, a constant amplitude input to the cam base provides a variable amplitude by changing the angle between the cam arm and the base.

Referring now to FIG. 2, a robot arm drive constructed and operative in accordance with one embodiment of the present invention includes a cam base 22 arranged for reciprocating linear motion over a trajectory 24Ka. It is illustrated in a side view. Cam base 22 is driven by any conventional device 23 including a crank, hydraulic piston, cycloid cam mechanism, or any other means for driving the cam base along track 24.

A cam arm 2 is attached to one end of the cam base 22 with the shaft 25 as the center.
6 are pivotally connected. A device 28 for changing the angle between the cam base and the cam arm is connected to the cam base 2.
20 is connected to the opposite end. As shown, the device 28 includes a small motor 30 for rotationally driving a screw element 32.

The threaded element 32 is connected to the opposite end of the cam arm 26, for example by a nut connected thereto.

Further, a cam follower 34 is connected to the cam arm 26 . Cam follower 34 may comprise any conventional cam follower connected to a robot arm to be moved. In a preferred embodiment, the cam follower 34 is a roller device 36 that engages a track defined by the cam arm 26 and is adapted to roll along the track in response to movement of the cam arm. have something Roller 36 is coupled to a transmission device that transmits the motion of the cam follower 34 to the motion of the robot arm.

In the illustrated embodiment, the roller arrangement 36 is attached to a cam follower 34 that is connected to a rack 40. rack 40
meshes with a gear 42 attached to the robot arm. This causes the rack 400 generated by the cam follower 34 to
The linear motion is converted into a rotational motion of the robot arm as desired. Alternatively, any other transmission device may be used to transmit linear motion to linear motion or linear motion to rotary motion.

As mentioned above, it can be seen from FIG. 2 that the initial position of roller 36 in each cycle is also its final position. In other words, during each cycle of a giston, cycloe cam, or other device for moving cam pace 22, row 236 fires and drives adjacent to the connection in shaft 25.

Thus, the robot arm always returns to its home position during various movements, and all of its various movements can be adjusted relative to this home position or reference point.

- In a preferred embodiment, the device for moving the cam base 22 and the device for changing the angle are computer controlled to move the robot arm to one or a series of desired positions.

It will be appreciated that the reciprocating cam base may be configured to support two or more independent cam arms, each cam arm having its own device for changing the angle between the cam arm and the cam base. Will.

Each of the cam arms supports a cam follower connected via a transmission to the portion of the rommet arm to be moved. FIG. 6 schematically shows such a variable cam mechanism configured to independently rotate two parts of a robot arm that are connected to each other. As can be seen in the drawings, a cam base 40 adapted for reciprocating linear movement is provided, to which two pairs of cam arms 42 are connected. A device 44 is provided for varying the angle θ between the two cam arms of each pair. A cam follower 46 is slidably coupled to one of the cam arms of each pair and is connected to a rack element 48.

Rack element 48 is pivoted about axis 50 in response to linear movement of the cam base.

The linear motion of the rack elements is transmitted via gear 52 directly to the lower arm of the robot as shown, or indirectly via a belt or other means to the upper arm of the robot as shown. Since the two pairs of cam arms and corresponding cam followers and rack elements are arranged one above the other, 1. They do not interfere with each other, and the angle between each pair of cam arms can be determined differently from each other.

It will be appreciated that any other type of transmission from the cam follower may alternatively be used to provide linear or other types of output motion.

According to one preferred embodiment of the invention, the device for changing the angle between the cam arms and the pace or between the paired cam arms is electronically or computer controlled.

Thereby, the desired path defined by the cam follower and the corresponding robot arm movement can be preprogrammed, and automation of the operation of the robot drive can be achieved. Alternatively, any or all parts of the mechanism may be mechanized or driven by any other device.

It will be understood by those skilled in the art that the invention is not limited to what has been illustratively shown and described above.

The scope of the invention is limited only by the following claims.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a robot arm drive in accordance with the present invention; FIG. 2 is a side view of a robot arm drive constructed and operative in accordance with one preferred embodiment of the present invention; and FIG. 3 is a side view of a robot arm drive constructed in accordance with the present invention. 2 is a schematic diagram of the drive device for the two parts of the robot arm, which is operated and acts; FIG. On the drawing above, 10, 22.40 is "cam base": 12
, 26.42 is "Cam arm J: 20, 34° 46 is [Cam follower J: 18, 32 is "Screw device": 14, 44 is "
The angle changing device J: 16, 30 is the motor, 42, 52 is the gear J: 40, 48 is the rack.

Claims (9)

[Claims] (1) A robot arm drive device including a variable cam mechanism; and a cam follower coupled in a driving relationship to the robot arm. (2) In the robot arm drive device according to claim 1, the variable cam mechanism includes: a base; a device for causing the base to make a reciprocating linear movement; and a cam arm pivotally connected to the base. a robot arm drive coupled to the cam follower; and a means for pivoting the cam arm relative to the base to produce a desired movement of the cam follower. (3) A robot arm drive device according to claim 2, wherein the cam arm pivoting device includes a selectively adjustable screw device connected between the base and the cam arm. Drive device. (4) In the robot arm drive device according to any one of claims 2 and 3: the robot arm drive device in which the cam arm pivoting device is computer-controlled. (5) The robot arm drive device according to any one of claims 2 to 4, wherein the device for moving the base is computer-controlled. (6) In the robot arm driving device according to any one of claims 1 to 5, the cam follower is connected to a rack, and the rack is connected to the robot arm to be moved. A robot arm drive device arranged to mesh with fixed gears. (7) An apparatus for driving at least two mutually connected parts of one robot arm, including: at least two variable cam mechanisms; and at least two cam followers; each cam follower is driven by said variable cam mechanism; A robot arm section drive arrangement arranged to follow each one of the cam mechanisms, each one of said cam followers being coupled to each one of said robot arm sections. (8) In the robot arm portion drive device according to claim 7, the variable cam mechanism includes at least two cam bases; at least two cam arms each connected to each base; and a robot arm section drive including a device for changing the angle between each base and its respective cam arm. (9) In the robot arm portion drive device according to claim 7, the angle changing device includes at least two small motors; and at least two screw mechanisms;
A robot arm section drive, wherein each of the motors is coupled to each of the screw mechanisms for driving a screw.