JPH10329081A - Robot motion limiting device and method - Google Patents

Abstract

(57) [Problem] To provide a robot operation restriction device that does not continuously supply a command to an actuator even when a robot arm reaches a movable range limit and does not finely adjust a mounting position of a stopper. I do. SOLUTION: In an operation restriction device for a robot having a mechanical stopper 102 for restricting a movement of a robot arm 103, a robot arm 10 is attached to the stopper 102.
3 is provided with a pressure-sensitive sensor 101 that responds when touched,
Further, there is provided means for cutting off a torque command supplied to the actuator of the robot arm when the pressure-sensitive sensor 101 detects the contact of the robot arm 103. This allows
When the robot arm 103 reaches the limit of the movable range, the pressure-sensitive sensor 101 detects a contact.
Fine adjustment of the installation position 1 is unnecessary, and the torque command can be cut off when the contact is detected, so that there is no need to supply a useless command.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for restricting the movement of a robot, which is applied to the drive of a joint of a manipulator or the like and mechanically restricts a movable range thereof.

[0002]

2. Description of the Related Art Conventionally, the limit of the movable range at the limit of the movable range of an actuator is as shown in FIG. In the figure, 401 is a limit switch, 402 is a rotating shaft, 403 is a robot arm, 404 is a load, and 405 is a stopper of the robot arm. Normally, the arrangement of the limit switch 401 and the stopper 405 is as shown in FIG. 4A, and when the robot arm 403 fixed to the rotating shaft 402 reaches the movable range limit, the limit switch 4
01 operates. The operation signal of the limit switch 401 is sent to the host controller, and the command is set to 0 for a speed command and fixed for a position command so that the robot arm 403 does not operate beyond the limit switch 401. The stopper 405 is provided for safety measures or the like. When the limit switch 401 does not operate for some reason, or when the load 404 is
Finally, the robot arm 403 is stopped in response to a load exceeding the maximum rated torque of the actuator in 2. Further, an arrangement of the limit switch 401 and the stopper 405 as shown in FIG.

[0003]

However, in the prior art, when the arrangement of the limit switch and the stopper is as shown in FIG. 4 (a), in order to prevent the robot arm from operating beyond the movable range limit, an actuator is required. There was a problem that it had to continue to supply the order to. In addition, if the limit switch does not operate for some reason, or if the robot arm is overloaded even if the command is continuously supplied, the robot arm will move beyond the movable range limit. there were. In addition, in the case where the arrangement of the limit switch and the stopper is as shown in FIG. 4B, the mounting position of the limit switch must be adjusted so that the limit switch can be operated when the robot arm contacts the stopper. However, there is a problem that the adjustment work takes time and effort. Therefore, the present invention does not continue to supply commands to the actuator even when the robot arm reaches the limit of the movable range, and can cope with a load exceeding the maximum rated torque of the actuator.
An object of the present invention is to provide a device and a method for restricting the operation of a robot without finely adjusting the mounting position of a stopper.

[0004]

In order to solve the above-mentioned problem, a robot motion limiting device according to the present invention is a robot motion limiting device having a mechanical stopper for limiting the movement of a robot arm. Provided with a pressure-sensitive sensor that responds when the robot arm comes into contact, and a unit that cuts off a torque command to be supplied to an actuator of the robot arm when the pressure-sensitive sensor detects contact with the robot arm. It is. Also, the robot operation limiting method according to the present invention has a mechanical stopper for limiting movement of the robot arm, and the stopper has a function of detecting a contact force. Detects the contact force when it contacts the stopper, and cuts off the torque command to be supplied to the actuator of the robot arm according to the contact force. By the above means, when the robot arm reaches the movable range limit, the pressure-sensitive sensor detects the contact, so that fine adjustment of the installation position of the pressure-sensitive sensor is unnecessary, and the torque command is issued at the time of detecting the contact. It can be disconnected and there is no need to supply useless commands. Further, since the movement of the robot arm can be restricted by the stopper, the robot arm can support a load exceeding the maximum rated torque of the actuator.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a structural explanatory view of an actuator with a stopper according to an embodiment of the present invention. As shown in the figure, this embodiment includes an actuator body 105, a stopper 102, a pressure-sensitive sensor 101 fixed to the stopper 102, a rotating shaft 104, and a robot arm 103 fixed to the rotating shaft 104. ing. Pressure sensor 10
For 1, a well-known sensor such as a pressure-sensitive conductive rubber can be used. In FIG. 1, when a torque command is supplied to the actuator, the rotating shaft 104 rotates and the robot arm 103 moves. When the robot arm 103 reaches the limit of the movable range of the robot arm 103, the pressure-sensitive sensor 10
Touch 1. The pressure sensor 101 can output the contact information. Therefore, in the present embodiment, when the robot arm 103 reaches the movable range limit, contact information between the robot arm 103 and the pressure-sensitive sensor 101 can be output. The stopper 102 allows the robot arm 103 to stop moving without exceeding the movable range even when the load 106 exceeds the maximum rated torque of the actuator on the rotating shaft 104.

FIG. 2 is a block diagram of an actuator with a stopper according to an embodiment of the present invention. As shown in the figure,
It comprises an actuator body 105, a rotating shaft 104, a pressure-sensitive sensor 101, a robot arm 103, a speed command amplifier 205, a torque command control unit 204, and a torque command amplifier 206. During a normal operation, the actuator body 105 receives the torque command from the speed command amplifier 205 via the torque command amplifier 206, and
Rotate 04. When the robot arm 103 reaches the movable range limit, that is, when the robot arm 103 comes into contact with the pressure-sensitive sensor 101, the contact information is transmitted to the pressure-sensitive sensor 10.
1 to the torque command control unit 204. When the contact information from the pressure-sensitive sensor 101 is input, the torque command control unit 204 cuts off the torque command,
Otherwise, do not cut. Therefore, when the robot arm 103 reaches the limit of the movable range, the torque command can be cut, and the load acting on the robot arm 103 can be supported without supplying the command by the stopper.

FIG. 3 is a configuration diagram of an application example using an actuator with a stopper according to an embodiment of the present invention. In the present embodiment, the manipulator unit 3 includes a manipulator base 303, a first actuator 304, a second actuator 305, and a third actuator 306.
01 and a hand unit 3 including an actuator body 105 with a stopper connected to a third actuator.
02. The actuator body 105 of the hand unit 302 includes a stopper 102, a pressure-sensitive sensor 101 fixed to the stopper 102, a rotating shaft 104, and a robot arm 103 fixed to the rotating shaft 104. In the figure, the supporting object 312 is held by the hand unit 302, that is, the robot arm 103 of the actuator body 105.
We support in. In general, the rated maximum torque of the actuator used in the hand section 302 is
01 is smaller than the rated maximum torque of the actuator used. Therefore, the weight of the object that can be supported by the robot arm 103 is determined by the maximum rated torque of the actuator constituted by the hand unit 302. However, in this embodiment, since the actuator body 105 with the stopper is used for the hand portion 302, even if the load of the supporting object 312 exceeds the maximum rated torque of the actuator body 105 on the rotating shaft 104, Stopper 10
2, the robot arm 103 supports the support object 312. Further, at this time, since pressure information is detected by the pressure-sensitive sensor 101, there is no need to supply a torque command to the actuator body 105, so that the efficiency is improved. Note that an actuator with a stopper may be used as the actuator of the manipulator unit 301 as necessary. In the above-described embodiment, an actuator having a rotating shaft is used, but the present invention is not limited to this.
An actuator having a linear motion shaft may be used.

[0008]

As described above, according to the present invention, the stopper capable of limiting the movable range, the function of detecting the contact between the robot arm and the stopper, and the pressure-sensitive sensor for contacting the robot arm are provided. Equipped with a means to cut the torque command supplied to the actuator of the robot arm when it detects the pressure, so that there is no problem of positioning and fine adjustment just by attaching the pressure-sensitive sensor to the stopper, and when the contact with the stopper is detected With this, the command can be disconnected, and there is an effect that no useless command is supplied. Further, since the robot arm is supported by the mechanical stopper, there is an effect that the robot arm can be supported even with a load exceeding the maximum rated torque of the actuator.

[Brief description of the drawings]

FIG. 1 is a structural explanatory view of an actuator with a stopper according to an embodiment of the present invention.

FIG. 2 is a block diagram of an actuator with a stopper according to the embodiment of the present invention.

FIG. 3 is a configuration diagram of an application example using an actuator with a stopper according to an embodiment of the present invention.

FIG. 4 is a conceptual diagram showing a movable range limit at a movable range limit of a conventional actuator.

[Explanation of symbols]

Reference Signs List 101 pressure sensor, 102 stopper, 103 robot arm, 104 rotation axis, 105 actuator body, 106 load, 204 torque command control unit, 20
5 Speed command amplifier, 206 Torque command amplifier, 30
1 manipulator section, 302 hand section, 303 manipulator base, 304 first actuator,
305 second actuator, 306 third actuator, 312 support object, 401 limit switch, 402 rotation axis, 403 robot arm, 404
Load, 405 stopper

Claims (2)

[Claims] 1. A motion limiting device for a robot having a mechanical stopper for restricting the movement of a robot arm, comprising: a pressure sensor responsive to a contact of the robot arm with the stopper; An operation limiting device for a robot, comprising: means for cutting off a torque command to be supplied to an actuator of the robot arm when a sensor detects contact of the robot arm. 2. A robot operation restriction method having a mechanical stopper for restricting the movement of a robot arm and having a function of detecting a contact force at the stopper, wherein the robot arm contacts the stopper. Detecting a contact force and cutting off a torque command to be supplied to an actuator of the robot arm according to the contact force.