JPS6126110A - Robot control system - Google Patents

Abstract

PURPOSE:To attain palletizing/depalletizing work extremely rapidly and precisely by fitting a detector for detecting a work to the head of a hand and loading/unloading each work by using the detector. CONSTITUTION:In case of depalletizing, the hand is moved from the uppermost position to the lowermost position with a comparatively slow speed. When the hand is moved up to the position where works are stacked and the detector 7 detects the works, a controller stops the movement of the hand. After stopping the movement, the controller stores the current position of the hand in a position memory on the basis of an automatic teaching instruction. After the automatic teaching, the work is griped and unloaded by the hand and rapidly moved to a point specified by positional data. Then, the initial operation is similarly repeated. When the absence of works is checked, a vacant magazine is moved to another position and the succeeding magazine containing works is carried.

Description

[Detailed Description of the Invention] (Prior Art) Various types of robots have been developed that have a plurality of operating axes that are driven by servo motors, servo valves, etc. and operate according to instructions from an n1 controller, and that have high operational versatility. It is effective in streamlining work, etc. For example, Japanese Patent Application Laid-Open No. 58-182
There is a method as disclosed in Japanese Patent No. 707. However, there are still many issues with the control method, and it is difficult to say that the performance of this highly versatile robot mechanism is fully utilized, and the control method is not truly easy to use when using the robot. . The present invention provides a control system that improves the current situation.

Robots) In order to operate, it is necessary to instruct the robot about the operating point, and there are methods using teaching, methods using numerical commands, and methods in which both teaching and numerical commands are possible. It is also possible to use the following methods.

(Problems to be Solved by the Invention) The purpose of the present invention is to load workpieces into a machine using a robot, depalletize workpieces stacked in a magazine in assembly work, take out one foot at a time, and reverse the process. Second, the palletizing work, in which workpieces that have been machined or assembled are stacked one by one in a magazine 1;'3, must be carried out reliably and at high speed.

The problems with robot systems for depalletizing and palletizing will be explained with reference to FIG.

In the system shown in FIG.
Grasp one piece at a time and load it into the machine 4. Machine 4
The workpieces that have been processed are vertically stacked from the machine 4 into a magazine similar to the unloader 1 by the hand 2 of the robot 1.

When performing vertical palletizing and depalletizing as described above, generally the height of the workpiece is moved in the vertical direction of the workpiece.
The positions are shifted one by one for positioning. However, in general, the workpieces are made with about 70 degrees of precision, and even if they are made, foreign objects may get caught between the workpieces, and they are not stacked at an even pitch. Moreover, since the errors are accumulated, when the hand finishes positioning, the hand often presses against the workpiece or fails to grip the workpiece.

(Structure of the Invention) In view of the above-mentioned current situation, the present invention provides a detector for detecting a workpiece at the tip of the hand, and uses this detector to ensure the above-mentioned palletizing operation and devaletizing operation. It is done at high speed. Moreover, it is possible to perform the process reliably no matter what amount of workpieces are initially placed in the magazine. Furthermore, this task requires very few operating points to be memorized.

(Example) Figure 2 shows the movement of the magazine and the hand relative to the magazine during vertical depalletizing and palletizing as in the system shown in Figure 1, and is carried out using the hand shown in Figure 8. I can do things.

The hand can move within the groove α formed perpendicularly to the nod of the magazine, and can grip the workpiece 5 in the magazine. In FIG. 2, the points indicated by ■ are the gripping positions during depalletizing, and the points indicated by ■ are the release positions during palletizing.

When the workpiece 5 is detected by the detector 7 for the first time after the detector 7 is attached to the hand and the workpiece detection signal is input,
The detector 7 is attached so that the workpiece 5 can be grasped by immediately stopping or by moving a little.

In the case of depalletizing, it is unknown how far in the magazine the workpieces are stacked, so when the workpieces are detected by the detector 7, the topmost part is moved at a relatively slow speed that allows the workpieces to be stopped without colliding with the soak. Move the node from to the bottom. In FIG. 2, the area that moves at this speed is represented by a dotted line. When the robot moves to the place where the workpieces are stacked, the detector 7 detects the workpieces, and a signal is input to the controller of the robot. Upon receiving this signal input, the robot controller stops the movement of the robot. Stopping the movement of the node by inputting this signal can be done using a very general technology by using the a'Pv used for the controller and the L8 construction such as the construction 10 boat. I won't go into details.

After stopping the movement, the robot controller stores the current position in the position memo IJ + trap by an automatic teaching command. The robot controller flits the current position of Notsuta
It is a matter of course that it is always remembered, and storing this n in a position memory is an extremely common technique, so we will not discuss the details of this n either. After self-teaching, the hand can grip the workpiece extremely reliably.

The self-teaching NFC position data is used to quickly perform the next workpiece removal operation. first,
Since there is no workpiece already at the first workpiece removal point indicated by the position data, there is no problem at all even if the band is moved at high speed to that position. Then, as in the beginning, move toward the bottom at a speed that allows it to stop without collision, and then perform exactly the same operation as in the beginning.

The high-speed movement operation point for the next workpiece take-out operation is self-taught. As the position of the work to be taken out becomes deeper each time, the movement distance becomes longer, but only the high-speed movement distance due to self-teaching becomes longer, so the overall time does not increase by that much.

Unless the movement target position T1 of the robot hand is below the position where the workpiece at the bottom can be gripped, the workpiece at the bottom cannot be reliably gripped. Therefore, the final operation is to confirm that there is no workpiece, and when it is confirmed that there is no workpiece, the empty magazine is moved to another location and another magazine containing a workpiece is brought.

Alternatively, the process moves to a separately specified operation, such as starting to take out a workpiece contained in another magazine in the same manner as t. Such operations are also generally controlled by a computer. Since this can be done using the same means as the conditional jump function, we will not go into details.

In the case of devaletizing, it is initially unclear how far the workpiece is stacked in the magazine, so it is necessary to check the amount of the workpiece without gripping the workpiece. Figure 2 shows the operation of palletizing 0.The basic operation is that when all the workpieces are detected, move them to the P22 target at a speed that allows them to stop without collision, and when the detection stops, move the Have them teach. Thereafter, in order to grasp the workpiece, the robot returns to the position where the workpiece is placed, and then makes the hand grasp the workpiece and moves it at high speed to a point above the self-teaching point by T8. , release the hand and let the workpiece fall.

T8 is a distance that takes into account variations in height direction such as accuracy of the work 't2, and is selected so that the work will not be scratched even if the work is released and dropped from a position shifted by this distance. The self-teaching point and T8 are treated as vectors as controller data, and shifting is performed by adding vectors.

In FIG. 2, the magazine is initially empty, and no workpiece is detected even when the target point is reached.

At this time, unlike when detection is stopped, from P2, T
8, all vector calculations are performed to shift the distance by the pitch T2 of one workpiece, and the resultant point n is set as the target value, and after moving at high speed in the same manner as described above, the workpiece is dropped.

After the hand is released, when the hand detects a workpiece, it moves as a PQf target at a speed that allows it to stop without collision, detects the workpiece, stops, self-teach its stop position, and then sets the T9i vector at the self-teaching point. calculate,
This result is used as the next work release position. Further, when the workpieces are fully stacked, the detector 7 moves the workpieces at high speed to the target position pB'1 where the workpieces can be detected. If no work is detected even after reaching the target position P8, the magazine is not full and the next palletizing operation is possible, so a similar work stacking operation is performed. In this way, after the workpieces have been stacked to the full in the magazine, the height of the stacked workpieces is detected and self-taught, and when the target is to be moved at high speed to detect the workpieces in P8, when the workpieces that have already detected the workpieces are Therefore, the workpiece can be detected without moving. By this, it is possible to detect that the magazine is full of workpieces, and it is possible to perform operations such as replacing the workpieces with the next magazine or palletizing them into another magazine.

FIGS. 4 and 5 are explanatory diagrams of the devaletizing and palletizing operations when the workpieces are kept close to each other horizontally, and a diagram of the hand used therein, respectively.

The hand shown in FIG. 5 is equipped with two detectors. Detector 8 is a detector used during depalletizing work, and detector 9 is a detector used during palletizing work.

The depalletizing operation differs from the depalletizing operation shown in Figure 2 in that the operating direction is changed from vertical to horizontal, and in particular, the detection movement operation is different in that linear movement is required. The operation sequence is exactly the same as that in FIG.

Straight line movement is a commonly performed motion and does not require a deep explanation.

The palletizing operation is performed using the detector 9. First, grasp the workpiece, set the leftmost workpiece as the target position F5i, and when detecting the workpiece by linear interpolation operation, move the hand until it detects the workpiece at a speed that allows it to stop without colliding with the detected workpiece. Move all.

In the palletizing process shown in FIG. 4, the magazine is initially empty, and the hand reaches the target point without stopping for detection. After reaching the target point, the position t vector shifted by the vector T5 is calculated, and the workpiece is gripped and moved at high speed to the resulting position during the next palletizing. After the movement is completed, P5-i is maintained at a speed that allows the workpiece to be stopped without colliding with the detected workpiece until the workpiece is detected.
i Move to target. After the detection stops, the stop position is taught by itself. The self-teaching point is used to calculate the position shifted by the vector T5 and to find the next workpiece gripping high-speed movement point. After self-teaching, the hand is at point P
5-i Move the workpiece to the target at high speed until it is detected. P6 selects a position where workpiece detection will work reliably when the workpieces are fully loaded. If the workpiece is not detected even after reaching P6t, the workpiece is still in a state where no workpiece can be inserted, and the same palletizing process as described above is continued.

When the workpiece is full, if you perform workpiece detection movement with the goal of "Pf)t", the workpiece has already been detected, so you can know that the workpiece is full without moving. , Ji performed the action of changing to the next magazine,
It is possible to perform operations such as barring and tying to another magazine.

In the vertical palletizing in FIG. 2, it is also possible to operate without detecting the amount of work, as in the horizontal palletizing when the detector 7 detects a workpiece one pitch below.

In the depalletizing work and palletizing mentioned above,
The movement of the workpiece must be linear, and the spatial posture of the workpiece must also be constant. In order to keep the spatial posture of the workpiece constant, when moving in the vertical direction, the Cartesian coordinate type, cylindrical coordinate type, and horizontal joint type (scalar type), all of which have a vertical movement axis, can be used without any problems. It is. Even in robots with vertical joints, the workpiece posture k
The technology to keep the temperature constant has already become a well-known technology in the world.

When moving in the horizontal direction, the orthogonal coordinate type is possible without any problems.In the cylindrical coordinate type and the horizontal joint type (scalar type), an operating axis is provided to rotate the hand in the horizontal plane, and the total horizontal rotation angle is This can be done by controlling so that it is always kept at 0.

(Effects) As explained above, according to the present invention, palletizing and depalletizing operations using robots can be performed very reliably and at high speed, and the economic effects thereof are remarkable.

[Brief explanation of the drawing]

Figure 1 shows palletizing. FIG. 2 is a side view of a general robot system that performs depalletizing work, and shows vertical palletizing according to the present invention. Fig. 4 is an explanatory diagram of movement operations when performing seven palletizing operations; Fig. 4 is an explanatory diagram of movement operations when performing horizontal palletizing and depalletizing operations according to the present invention;
8 and 5 are perspective views of the hand used during the work shown in FIGS. 2 and 4. FIG. In the figure, 1 is a robot, 2 is a hand, 8 is a magazine, 4 is a machine, 5.6 is a workpiece, and 7 and 8.9 are detectors.
Above Figure 2 Figure 3

Claims (4)

[Claims] (1) In a robot control method that stores a robot operating position and executes the operation according to a programmed sequence at the memorized operating position, there is a means for inputting a signal from a detector, and a means for inputting a signal from a detector; When a specified signal level is detected from the specified signal input means while moving the hand, the signal level of the input is not detected even if the movement of the hand is stopped and the target position is reached. means to perform a separately specified action;
A robot control method having means for automatically self-teaching the current position. (2) The robot control system according to claim 1, wherein the detector that generates an input signal for stopping movement of the hand is attached to the tip of the hand. (3) The action of moving the hand toward the target position is
3. The robot control system according to claim 1, wherein the robot control method is a motion that moves the hand linearly and does not change the posture of the hand. (4) A robot control system according to claim 1, 2, or 8, characterized in that the robot control system has a function of performing vector calculations on coordinate values.