JPH01310885A - Industrial robot device - Google Patents

Abstract

PURPOSE:To obtain a compact constitution of a robot by connecting a hydraulic type or pneumatic type balancer between the arm of the robot and a driving shaft for driving the arm and applying a prescribed revolution torque onto the arm by the balancer, thus reducing the dimension of a driving device for the arm. CONSTITUTION:When a balancer 10 connected between an arm 3 and a driving shaft (output shaft 1 of a reduction gear 5) is applied with a hydraulic pressure or air pressure, the shaft of the balancer 10 revolves, and the turning moment revolves the arm 3. Therefore, the driving torque to be applied onto the arm 3 of a vertical joint type robot from a driving device 4 can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement of an arm drive unit of an industrial robot device.

[Prior Art] In industrial robots, especially vertically articulated robots, the load applied to the drive motor varies significantly depending on the posture of the arm.

[Problem to be solved by the invention] Therefore, the robot is generally equipped with a large capacity drive motor that can provide sufficient drive even when the heaviest load is applied to the arm, which makes the robot as a whole expensive. Not only that, but it also became larger and heavier, requiring a larger installation space and requiring a stronger foundation for installing the robot.

The present invention has been made to solve the above problems, and an object of the present invention is to obtain an industrial robot device that can sufficiently drive a robot arm even with a small drive device.

[Means to solve the problem]

An industrial robot device according to the present invention includes a hydraulic or pneumatic balancer connected between an arm of a vertically articulated robot and a drive shaft that swings the arm, and this balancer applies a predetermined rotational torque to the arm. This makes it possible to grant the following.

[Operation] In the present invention, when hydraulic or pneumatic pressure is applied to the balancer connected between the arm and the drive shaft, the shaft of the balancer rotates and this rotational force rotates the arm. It is possible to reduce the drive torque that must be applied to the

〔Example〕

An embodiment of the present invention will be described with reference to the drawings. First, the overall configuration of an industrial robot device to which the present invention is applied will be explained with reference to FIGS. A first arm drive motor (4) for driving the first arm (3) and a reducer (5) for this motor (4) are arranged on one side, and on the other side of the main body (2). is the second arm (6) Second arm drive motor for driving
(7) and a reducer (8) for this motor (7). The first arm (3) as an arm is
The lower part is supported by this main body (2) and swings around the center (9), but this first arm (3) and a reducer (5) serving as a drive shaft that swings the first arm (3)
) between the output shaft of the hydraulic or pneumatic balancer (
lO) are connected. This balancer (10) is configured to be able to apply a predetermined rotational torque to the first arm (3), as will be described later. The second arm (6) is supported on the upper part of the first arm (3), and the center (11)
A load (12) is applied to one end of this second arm (6).

This second arm (6) includes a lever (13) fixed to the output shaft of the reducer (8) and driven to swing, and a lever (
13) and a lever (15) which is connected to the second arm (6) and forms a second arm drive link (14), and is swung by the second arm drive motor (7).

FIG. 3 is a sectional view taken along the line III--III in FIG. 1, showing the internal structure of the balancer (10).
) is provided, and one end of this shaft (22) is connected to a reducer (
5), and the other end is fixed to the first arm (3). This rotation axis (22) has a
A rotary piston (23) that swings together with the main body (21) is fixed.
The space inside is divided into a right ventricle (24) and a left ventricle (25). The right ventricle (24) and left ventricle (25) are provided with pipes (26) and (2) for supplying or discharging oil or air, respectively.
7) is connected. Therefore, when hydraulic pressure or pneumatic pressure is applied to the left ventricle (25), the piston (23) swings clockwise, and when hydraulic pressure or pneumatic pressure is applied to the right ventricle (24), the piston (23) swings counterclockwise. move. As a result, the rotation shaft (22) also rotates clockwise or counterclockwise.

Next, referring to Figures 4 and 5, we will explain the fluctuations in the load torque applied to the first arm (3). As shown in Figure 4, the first arm (3) is most tilted towards the load (12) side. When the load (12) is located farthest from the center position (A) of the first arm drive motor (4), the load torque of the first arm drive motor (4) becomes maximum, as shown in FIG. In addition, when the loads on the left and right sides of the center position (A) are balanced, the load torque becomes the minimum. This variation in load torque is caused by not only the first arm (3) but also the second arm (3).
(6) also occurs, but the fluctuation rate is generally larger in the first arm (3). Therefore, this embodiment shows a case where the balancer (10) applies a predetermined rotational torque to the first arm (3).

Next, control of the balancer (3) will be explained based on FIGS. 6 to 8. The swing angle of the first arm (3) is 01,
If the swing angle of the second arm (6) is θ, then on the wood flow side, the load on the drive motor (4) is calculated by constantly monitoring the angles θ1, θ2 and the three-line nature of the load (12). The results are fed back to hydraulic or pneumatic discharge amount control, so that even a small drive motor (4) can sufficiently drive the robot.

That is, as shown in FIG. 6, first, the load torque of the robot parts driven by the first arm drive motor (4) is calculated corresponding to the angles θ1 and θ2 (ST-31),
Calculate the load torque on the first arm drive motor (4) due to the load (12) corresponding to angles θ1 and θ2 (ST-32
). Next, the first arm drive motor (
Calculate the total load torque of 4) corresponding to the angles θ1 and θ2. 5T-33) Calculate the difference in capacity with the capacity of the first arm drive motor (4) 5T-34) The first arm drive motor (4) Drive the balancer (10) to compensate for the lack of capacity (ST-351) By the way, since robot work generally involves repeating the same work, it takes a lot of effort to perform the above calculations while the robot is operating. Since a large-capacity computer is required, the above calculation may be calculated in advance and a list of command values at each operating point may be created and stored in the robot's calculation unit in advance. This is a graph related to this embodiment, which shows motor capacity B and motor capacity deficiency C (hatched area in the figure) in relation to the angles θ1 and θ2.This motor capacity deficiency will be compensated for by the balancer capacity. .θ1A to θ3. are the ever-changing values of θ1, and θ2
A to θ2E each indicate the ever-changing value of θ2. FIG. 8 is a block diagram of this embodiment,
The robot drive device (41) is the robot control device (4
2) and the I10 port (43), and the drive (48) of the balancer (lO) is connected to the control device (4) of the balancer.
9) and the RAM (44) via the I10 port (43)
, a ROM (45), and a CPU (46). Further, arm angle θ1, θ2 information (50) and load information (51) are input manually to the I10 boat (43).

Therefore, in this embodiment, if the load on the movable part exceeds the capacity of the drive motor due to the robot's posture at the rotation axis of the vertically articulated robot, a hydraulic or pneumatic system is installed between the reducer and the member to be driven. A balancer is installed to detect the difference between the load torque on the motor and the motor capacity, which changes moment by moment during robot operation, and only compensate for the excess motor capacity using the balancer. The load torque on the motor, which changes from moment to moment, is calculated in advance, and a list of balancer operation command values at each operating point is stored in the robot, so that the balancer operation command corresponding to the robot's posture can be issued. You may also do so.

Although the above embodiment has been described with respect to the first arm drive motor (4), the present invention can be similarly applied to other drive motors and the effects can be obtained.

[Effects of the Invention] Since the present invention is configured as described above, the drive device can be downsized, and the industrial robot device can be made compact and inexpensive as a whole.

[Brief explanation of the drawing]

1 to 8 are diagrams showing one embodiment of the present invention, and FIG. 1 is an overall configuration diagram of an industrial robot device, and FIG.
2 is a front view showing the whole, FIG. 3 is a sectional view taken along line III--III of FIG. 1, FIGS. 4 and 5 are front views showing the robot's operation, and FIG. FIG. 7 is a flowchart, FIG. 7 is a graph diagram, and FIG. 8 is a block diagram. (3) Arm (first arm), (6) Arm (second arm), (10) Balancer. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] A hydraulic or pneumatic balancer is connected between the arm of the vertically articulated robot and a drive shaft for swinging the arm, and the balancer is capable of applying a predetermined rotational torque to the arm. Industrial robot equipment.