JPS58708A - Work grip position recognizing method of mechanical hand of robot - Google Patents

Abstract

PURPOSE:To exactly control a robot, by stopping an arm at the time point when a work moved by moving the arm of a mechanical hand has been made to abut to a reference point, and recognizing a grip position of the mechanical hand in the work by relation of a position of the reference point and the mechanical hand. CONSTITUTION:A microswitch 6 is installed to a base part 7 of a robot body, and a position where the switch 6 is turned on when its operating piece 6a has been pushed is set at a reference point P. A position of the operating piece 6a in this point P, in operating space coordinate systems (x), (y) and (z) of the robot is already known, and when the switch 6 is turned on, movement of an arm 4 of the robot is stopped. The robot grips a work W by a mechanical hand 5, and after that, moves the hand 5 so that a surface S of the work W abuts to the operating piece 6a. When the surface S abuts to the operating piece 6a and the switch 6 is turned on, movement of the hand 5 is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for recognizing a work gripping position of a mechanical hand in a robot.

In recent years, welding and painting have become particularly popular in the manufacturing and processing industry.

In response to the strong demand for automation of machining, assembly, inspection, measurement processes, etc., various industrial robots are being actively developed.

For example, so-called intelligent robots that can act autonomously and have various movement functions, recognition functions, and sensory functions similar to those of human upper limbs are becoming mainstream as industrial robots. .

In such an intelligent robot, for example, it grasps. Since a mechanical node equivalent to a human hand with grasping functions such as grasping and pinching is required, the development of this mechanical node is also very active.

By the way, most of the basic structures of mechanical grippers developed today grasp the workpiece W by holding it between two gripping parts (fingers) 1 and 2, as shown in Figure 1. ℃・ru.

Therefore, when grasping the workpiece W with the gripping parts 1 and 2, it is necessary to detect and grasp a predetermined position (for example, the center position) in the direction of the arrow A on the workpiece W, and grasp the workpiece W in the direction of the arrow A. Since the position is unstable, the following problem occurs when assembling the grasped workpiece W at a predetermined location.

For example, when storing the grasped work W in the storage section 6a of the container B, the robot calculates the target position of the mechanical hand 50 attached to the tip of the arm 4, and
In order to control the movement of the mechanical hand 5, if the gripping position of the mechanical hand 5 on the workpiece W is uncertain, the mechanical hand 5
It is not possible to determine to what position the workpiece W should be moved relative to the storage section 3a of the container B to store the workpiece W.

This problem can be solved by detecting and grasping a predetermined position on the work W in the direction of arrow A when grasping the work W, but in order to do this, for example, it is necessary to equip the robot with a visual function. There is a problem in that the control becomes complicated, such as by making it possible to recognize the pattern of the workpiece W by using the pattern recognition method, and then performing feedback control based on the pattern recognition.

In addition, the above problem can be solved by providing a mechanical hand that can wrap around the entire workpiece W and uniquely determine the grasping position on the workpiece W, but then the mechanical hand becomes large and lacks versatility with respect to the workpiece. There are problems such as.

This invention was made in view of the above points, and is a robot equipped with a mechanical hand at the tip of the arm.
The mechanical hand that has gripped the workpiece is moved toward a preset reference point by moving the arm, and when the workpiece comes into contact with the reference point, the movement of the mechanical hand is stopped and the mechanical hand is moved toward the reference point. The present invention aims to solve the above-mentioned problems by providing a method for recognizing a workpiece grasping position of a mechanical hand in a robot, which recognizes the grasping position of the mechanical hand on the workpiece based on the positional relationship between a point and the mechanical hand.

Embodiments of the present invention will be described below with reference to FIG. 2 and subsequent drawings.

FIGS. 2 and 3 are a perspective view and a front view showing an embodiment of the present invention. In both figures, parts corresponding to those in FIG. 1 are designated by the same reference numerals, and their explanations will be omitted.

In both figures, the microswitch 6 is attached, for example, to the base 7 of the robot body (not shown), and its actuator 6
The position where a is pressed and the microswitch 6 is turned on is set to be the reference point P (FIG. 6). The position of the actuator 6a at this reference point P in the robot's working space coordinate system (indicated by g, y, and t in Fig. 2) is known, and when this microswitch 6 is turned on, the movement of the robot's arm 4 is controlled. It is supposed to stop.

After the robot grasps a workpiece W placed at a predetermined location (not shown) with a mechanical hand 5, the surface S of the grasped workpiece W touches the actuator 6 of the microswitch 6.
By moving the arm 4, the mechanical hand 5 is moved toward the actuator 6a so as to come into contact with the actuator 6a.

Note that if the operating position (reference point P) of the actuator 6a of the microswitch 6 is (26, vQj 'O), then in the structure of the mechanical hand 5 in this embodiment, gQ
, ν0 can be defined in advance, so by arbitrarily defining the coordinates in two directions and varying the position in the fog direction from there,
The mechanical hand 5 can be moved so that the surface S of the workpiece W comes into contact with the actuator 6a of the microswitch 6.

When the surface S of the workpiece W comes into contact with the actuator 6a of the microswitch 6 and the microswitch 6 is turned on, the arm 4 immediately stops moving and the mechanical arm 5 stops moving.

In this way, the position of the mechanical node 5 in two directions can be known from the output of the internal sensor (for example, a potentiometer) provided at each joint part of the arm 4 of the robot. The distance from to the grasping position of the gripping parts 1 and 2 can be recognized by calculating lto-2□1, and thereby the grasping position of the mechanical node 5 on the workpiece W can be recognized accurately.

Therefore, based on the recognition result, the storage section 3a of container B is
By calculating the movement target position of the mechanical node 5 relative to the position, the workpiece W can be reliably stored in the storage section 6a of the container B even if the grasping position when the workpiece W is grasped is uncertain.

Alternatively, as shown in FIGS. 2 and 6, the operating position of the actuator 6a of the microswitch 6, that is, the reference point P, may be set near the widthwise center of the inner surface of one longitudinal end of the storage portion 6a of the container 6. If they match, the workpiece W can be stored in the storage section 6a by lowering the mechanical hand 5 vertically from the stopped position in the ν direction (Fig. 2) without performing the above calculation. I can do it.

In the above embodiment, the reference point P is set to the microswitch 6.
However, the setting is not limited to this, and for example, a piezoelectric switch or the like may be used. or,
The reference point P may simply be formed by a fixed part, and a sensor capable of detecting the contact between the reference point P and the surface S of the workpiece W may be provided on the gripping part 1.2 of the mechanical hand 5. .

Further, in the above embodiment, two directions (second
Although the description has been made regarding the mechanical hand in which the grasping position shown in FIG.

Further, in the above embodiment, the reference point P is provided at the base of the robot, but the reference point P is not limited to this, and may be provided, for example, at a fixed part separate from the robot.

As described above, by using the method for recognizing the workpiece grasping position of a mechanical hand according to the present invention, not only can a versatile mechanical hand be used, but recognition is also easy, making it suitable for controlling robots. be.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing a grasping state of a workpiece by a mechanical hand and a container for storing the workpiece, which serves to explain the background of the present invention; Fig. 2 is a perspective view showing an embodiment of the present invention; FIG. 3 is a normal view of FIG. 2. 1.2... Gripping part 6... Container 6a... Storage part 4... Arm 5... Mechanical hand 6... ...Micro switch 6a... Actuator 7... Base W of robot body... Work Figure 1

Claims (1)

[Claims] 1. In a robot equipped with a mechanical hand at the tip of an arm, the mechanical hand that grasps the workpiece is moved toward a preset reference point by moving the arm, and when the workpiece comes into contact with the reference point, A method for recognizing a work gripping position of a mechanical hand in a robot, wherein the movement of the mechanical hand is stopped and the gripping position of the mechanical hand on the workpiece is recognized based on the positional relationship between the reference point and the mechanical hand.