JPH08393B2 - Robot arm with collision prevention function - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a robot arm with a collision prevention function including a collision prevention device for preventing a collision between a robot arm and an obstacle.

[0002]

2. Description of the Related Art Conventionally, as a collision preventing device for a robot arm, one disclosed in JP-A-3-49886 as shown in FIG. 2 or JP-A-2-292186 as shown in FIG.
And the like.

In the collision prevention device shown in FIG. 2, the output value of the force detection signal obtained from the force sensor 20 (including the end effector 30) attached to the robot arm 7 is compared with a predetermined threshold value. Thus, the presence or absence of a collision is identified, and the robot arm 7 is controlled to move.

On the other hand, in the collision prevention device shown in FIG. 3, the robot arm 7 is covered with a cushioning member 8 for absorbing the impact at the time of collision.

[0005]

In the case of the collision prevention device shown in FIG. 2, the obstacle is actually collided with the robot arm to apply stress, and the movement of the robot arm is stopped by the operation of the control system. Since there is a considerable time delay before avoiding contact, a considerable force is expected to be applied between the robot arm and the obstacle. In such a case, there is a risk that both the robot arm and the obstacle will suffer large mechanical damage.

Further, in the case of the collision prevention device shown in FIG. 3, since it has a function of merely absorbing an impact, the movement of the robot arm leading to a collision cannot be avoided. For this reason, after the collision, the robot arm continues to move in a state of mechanically interfering and quasi-static stress is applied, and in this case also, both the robot arm and the obstacle may suffer large mechanical damage. There is a nature.

The present invention has been made to solve the above problems, and its technical problem is to be able to sufficiently reduce the impact at the time of collision with an obstacle, and to mechanically damage both the robot arm and the obstacle. It is to provide a robot arm with a collision prevention function capable of minimizing the above.

[0008]

According to the present invention, in a robot arm with a collision prevention function including a collision prevention device for preventing a collision between the robot arm and an obstacle, the collision prevention device has a tactile sensation on the outside of the robot arm. A sleeve and a support portion that elastically supports the tactile sleeve to the robot arm,
A stress sensor that outputs a stress signal that represents the stress generated in the support portion and an arm position control device that controls the position of the robot arm based on the stress signal are further included .
The controller controls the tactile sleeve and the obstacle based on the stress signal.
A collision detection unit that detects the occurrence of a collision with
Arm drive that moves the robot arm in a direction that reduces stress
The tactile sleeve includes the moving parts and the side surfaces facing each other.
In addition to having each side surface as a support portion, the stress sensor is
It is possible to obtain a plurality of robot arms with a collision prevention function, which are provided in a pair configuration facing each other on each side .

Further, according to the invention, in the robot arm with the collision preventing function, the arm position control device further comprises:
One pair of stress sensors placed on a horizontal plane
From the sum of the stress signals of one configuration, the response of the other
Horizontal difference value after subtracting the sum of force signals and on the vertical plane
From the sum of the stress signals of one pair configuration placed on the other
Vertical difference value obtained by subtracting the sum of stress signals of paired components
Collision detection and collision in robot arm based on
A collision detection unit that outputs a detection signal and a collision detection signal
And a collision prevention control unit that controls the position of the robot arm.
A robot arm with a collision prevention function including is obtained.

[0010]

[0011]

[0012]

In the collision preventing device of the present invention, the stress sensor is attached to the supporting portion of the tactile sleeve elastically supported on the outside of the robot arm, and the arm position control device uses the tactile sensor based on the stress signal from the stress sensor. After determining the stress generated in the sleeve, the position of the robot arm is controlled in the direction opposite to the stress direction.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A robot arm with a collision prevention function according to the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 shows a basic configuration of a robot arm with a collision prevention function according to an embodiment of the present invention.

In this collision preventing device for a robot arm with a collision preventing function, the side surfaces (bottom surfaces) facing each other are supported by the supporting portion 1.
a and 1b, and a hollow cylindrical tactile sleeve 1 elastically coupled to the outside of the robot arm 7 at its hollow portion,
A plurality of stress sensors 3a to 3d and 3e to 3h attached to the supporting portions 1a and 1b of the tactile sleeve 1 respectively.
And an arm position control device 4 for controlling the position of the robot arm 7 while being connected to the stress sensors 3a to 3h.

Of these, the stress sensors 3a-3d, 3e-
3h is a pair configuration (3a and 3e, 3b and 3f, 3c and 3g, which faces the supporting portions 1a and 1b, as shown in the figure).
3c and 3g, 3d and 3h), and elastic stress generated in the supporting portions 1a and 1b is detected to output a stress signal. Further, the arm position control device 4 controls the position of the robot arm 7 in the direction opposite to the direction of the stress generated in the support portions 1a and 1b according to the input stress signal.

The arm position control device 4 further subtracts the sum of the stress signals of the other pair configuration from the sum of the stress signals of the one pair configuration of the stress sensors 3a to 3h placed on the horizontal plane. Horizontal H difference value F _H [F _H =
Represented as (3b + 3f)-(3d + 3h)],
And a vertical direction V difference value F _V [F _V = (3a + 3e) − (3c) obtained by subtracting the sum of stress signals of the other pair configuration from the sum of stress signals of one pair configuration placed on the vertical plane.
+ 3g)], a collision detection unit 4a that detects a collision in the robot arm 7 and outputs a collision detection signal, and position control of the robot arm 7 based on the collision detection signal from the collision detection unit 4a. And a collision prevention control unit 4b.

That is, the collision detection unit 4a performs coordinate conversion processing and threshold processing based on the stress signals from the respective stress sensors 3a to 3h, thereby detecting collision including presence / absence of collision and collision direction at the time of collision. Output a signal. In addition, the collision prevention control unit 4b causes the robot arm 7 to move from the collision occurrence direction when it is determined that an actual collision has occurred based on both the presence or absence of the collision in the collision detection signal and the collision direction at the time of the collision. Robot arm 7 to move in the opposite direction
The position control signal L is output to the arm drive control unit (not shown) for the. Therefore, the arm drive control unit can be regarded as included in the arm position control device 4.

In this robot arm with a collision preventing function, even if there is a collision with an obstacle during the moving operation, the robot arm 7 itself is provided with a tactile sleeve 1 having elasticity, and the arm position control device 4 is used. Each stress sensor 3a
After the stress generated in the tactile sleeve 1 is determined based on the stress signal from ~ 3h, the robot arm 7 is rapidly position-controlled in the direction opposite to the stress direction, so that the impact is sufficient when the robot collides with an obstacle. Before it is absorbed and both the robot arm 7 and the obstacle suffer great mechanical damage, the position is moved to avoid mechanical damage.

[0019]

As described above, according to the robot arm with the collision prevention function of the present invention, the tactile sleeve is elastically supported by the robot arm, and the elastic strain generated when the robot arm collides with the obstacle. The direction of the collision is detected by measuring the stress, and the position of the robot arm is controlled in the direction that avoids this, so the impact force at the time of the collision is absorbed and alleviated. The resulting quasi-static stress is also avoided so that mechanical damage due to the collision of the robot arm with the obstacle is minimized. As a result, the risk of a large collision between the robot arm and the obstacle and the resulting accident such as a contact accident can be reliably prevented.

[Brief description of drawings]

FIG. 1 is a diagram showing a main configuration of a robot arm with a collision prevention function according to an embodiment of the present invention.

FIG. 2 is a diagram showing a main part configuration of a conventional robot arm with a collision prevention function.

FIG. 3 is a diagram showing a main part configuration of another conventional robot arm with a collision preventing function.

[Explanation of symbols]

 1 Tactile sleeves 1a, 1b Supports 3a-3g Stress sensor 4 Arm position control device 4a Collision detection unit 4b Collision prevention control unit 7 Robot arm

Claims (2)

[Claims] 1. A robot arm with a collision prevention function, comprising a collision prevention device for preventing a collision between a robot arm and an obstacle, wherein the collision prevention device comprises a tactile sleeve outside the robot arm and the tactile sleeve. A support portion elastically supported by the robot arm, a stress sensor that outputs a stress signal representing a stress generated in the support portion, and an arm position control device that controls the position of the robot arm based on the stress signal. And further, the arm position
The placement control device is configured to perform the tactile sensation three-dimensional movement based on the stress signal.
Collision detection unit for detecting the occurrence of a collision between the obstacle and the obstacle
And when the collision occurs, the robot arm receives the stress
And an arm driving unit that moves the
The sleeve has side surfaces facing each other, and
The side surface is used as the supporting portion, and the stress sensor is provided on each side surface.
A robot arm with a collision prevention function, characterized in that a plurality of robot arms are provided in a pair configuration facing each other . 2. A robot with a collision prevention function according to claim 1.
In the arm, the arm position control device further includes:
One pair of stress sensors placed on a horizontal plane
From the sum of the stress signals of one configuration, the response of the other
Horizontal difference value after subtracting the sum of force signals and on the vertical plane
From the sum of the stress signals of one pair configuration placed on the other
Vertical difference value obtained by subtracting the sum of stress signals of paired components
To detect a collision in the robot arm based on
A collision detection unit that outputs a collision detection signal;
Collision for position control of the robot arm based on
An anti-collision function equipped with an anti-collision control unit.
Bot arm.