JPH0419093A - Robot collision detecting device - Google Patents

Abstract

PURPOSE:To detect the generation of a collision only when the collision is actually generated by providing a judging means for judging the generation f the collision when the value of an impact signal becomes larger than a judgment level changed at real time according to the grade of load signals. CONSTITUTION:A robot collision detecting device is provided with a load detecting means for outputting load signals corresponding to the load acting upon a tool (grinder) 3 provided at a robot 1, and an impact detecting means 30 for detecting impact force acting upon the robot 1 so as to output an impact signal indicating the grade of the impact force. A judgment level is then changed at real time according to the grade of the load signal, and when the value of the impact signal becomes larger than this judgment level, a judging means 11 judges that a collision is generated. Accordingly, even if impact force is generated during grinding, wrong judgment on the generation of a collision can be prevented from being made.

Description

[Detailed Description of the Invention] Industrial Application The present invention relates to a collision detection device for robots, and is intended to improve collision detection sensitivity. Collisions are accurately detected by raising the collision determination level at times and lowering the collision determination level when a very large force is not required.

C1 Conventional technologyIn industry, various types of robots have been introduced due to the demand for increased efficiency in high-mix, low-volume production and the decrease in the number of skilled workers. FIG. 4 shows an example. In this example, the hand 2 of the robot 1 is equipped with a grinder 3, and the burr 4 of the casting 4 is
Remove a.

By the way, if the robot 1 collides with a workpiece or an obstacle due to an erroneous operation or the like, the workpiece, tool, or robot will be damaged, so it is desirable to stop the robot 1 as soon as possible after the collision. In addition, because a collision increases the position difference, speed deviation, torque deviation, etc. in the robot control system (feedback control system), control is performed to increase the torque in the direction of the collision, which may increase damage. From this point of view as well, it is desirable to stop the vehicle as soon as possible after the collision.

Detect collisions of robot 1; this is done by equipping robot 1 with dedicated sensors (force sensors, strain sensors, etc.) for collision detection, and determining based on deviations within the robot control system. .

D. Il that the invention tries to solve! As shown in Figure 4, when performing work that requires a large amount of force, such as deburring, a large impact force is applied to the robot l even during normal operation, resulting in a collision even though the robot has not collided. In some cases, the operation of the robot 1 may be stopped due to an erroneous determination that a problem has occurred.

In view of the above-mentioned prior art, the present invention provides collision detection for robots that can accurately detect collisions even in robots that perform tasks that require large forces such as grinding and polishing, and therefore are subjected to relatively large impact forces even in normal operation. It provides equipment.

E, l! Means to solve the problem i! :I! The configuration of the present invention that solves this problem includes a load detection means that outputs a load signal corresponding to the load acting on a tool equipped on the robot, and a load detection means that detects the impact force acting on the robot. llf that outputs an impact signal indicating the magnitude of impact force
impact detection means; and determination means for determining that a collision has occurred when the determination level changes in real time in response to the magnitude of the load signal and the value of the impact signal increases. It is characterized by having.

F. Operation In the robot collision detection device of the present invention, when a tool is performing work such as grinding, the collision determination level is high, and when the above work is not performed, the collision determination level is low. Even if an impact force is generated, it will not be erroneously determined that a collision has occurred.

G. Example Embodiments of the present invention will be described in detail below based on the drawings.

Note that the same reference numerals are given to parts that perform the same functions as those in the prior art.

As shown in FIG. 1, a robot 1 having a hand 2 equipped with a grinder 3 is operated by a pure machine 10 to grind away burrs 411 of a casting 4. In this case, burr 4a
When grinding a large one, the load acting on the grinder 3 becomes large and the grinder current I flows through the grinder 3. As the value of increases, grinder 3
A large vibration (impact force) is transmitted from the to the hand 2. The hand 2 is equipped with a force sensor 3o for detecting impact force, and an l1ff strike signal S corresponding to the impact force is output.

Note that the driving trajectory of the robot 1 and the like are taught by the teaching box 20.

As shown in the processing system of FIG.
It is connected to the ROM (ROM) 14. Further, the teaching box 20 is connected to the bus 12 via the interface 15, and the robot 1 is connected to the bus 12 via the input/output interface 16. Then, the impact signal S output from the force sensor 30 is processed through the interface 17 Wl! 11, the grinder current I. is sent to the processing circuit j@11 via the analog input interface 18.

The processing circuit 11 uses the determination characteristic as shown in FIG. 3, that is, the determination characteristic in which the determination level changes in real time in proportion to the value of the grinder current, to determine whether the value of the shock signal S is higher than the determination level at that time. It is determined that a collision has occurred when the value of the impact signal S is higher.

When grinding a large burr 4a, large vibrations occur, but at this time, the grinder current I6 increases and the judgment level is also high, so it is not judged as a collision, and a collision actually occurs and a large impact force is generated. It is determined that a collision has occurred when the collision occurs. Furthermore, since the determination level is lowered when no grinding work is being performed, it can be determined that a collision has occurred even when a small impact force occurs, so that the collision detection sensitivity is increased.

H9 Effects of the Invention As specifically explained with the examples, according to the present invention, even if large vibrations (shocks) occur due to work, it is not incorrectly determined that a collision has occurred, and it is not determined that a collision actually occurred. Only occasionally can collisions be detected. Also, when not working, collision detection sensitivity is high.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a block diagram showing a processing system of the embodiment, Fig. 3 is a characteristic diagram showing determination characteristics, and Fig. 4 is a block diagram showing a robot. . In the drawing, 1 is a robot, 2 is a hand 3 is a grinder, 4a is a paris, 10 is a control device, 11 is a processing circuit, 18 is an analog interface, and 30 is a force sensor. Patent Application Co., Ltd. Osamu Akiyo

Claims (1)

[Scope of Claims] Load detection means that outputs a load signal corresponding to the load acting on a tool provided on the robot, and detecting an impact force acting on the robot and outputting an impact signal indicating the magnitude of the impact force. and determining means for determining that a collision has occurred when the value of the impact signal becomes larger than the determination level, the determination level of which changes in real time in response to the magnitude of the load signal. A robot collision detection device characterized by: