JPH08132367A - Work position detecting and work positioning method by industrial robot and device therefor - Google Patents

Abstract

PURPOSE: To complete a positioning control system on a robot side as much as possible by detecting at detection portions a relative movement state to a work hand portion or an arm, judging, on the basis of detected data, whether or not a work is in a correct position. CONSTITUTION: At a hand portion 11 or an arm portion 8 on the robot 1 side, a portion 12 that is relatively moved according to its force at the time of a work 13 having butted against a positioning member and detection portions S1, S2 that detect its movement are provided. Next, by means of reaction that has been butted against the positioning member, data regarding position propriety and the data of action to conduct position correction are obtained. The detection portions S1, S2 are made to be the ones to detect whether or not a movement quantity is within a predetermined range, and the presence of movement and whether the movement is within the predetermined rang or not are detected, and when there has been a movement within the predetermined range, it is judged to be a correct position, and when there has been no movement, or the movement quantity has exceeded the predetermined range, it is judged to be an incorrect position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an industrial robot (hereinafter,
The present invention relates to a work positioning method and a work positioning device by a robot. More specifically, robots handle and supply workpieces such as plate materials to plate material processing machines such as press brakes, NC turret punch presses, roll forming machines, and routers, and the robot and plate material processing machines cooperate to bend and punch plate materials. The present invention relates to a method for detecting the adequacy of a workpiece supply position from a robot to a plate processing machine, a positioning method, and an apparatus used for those methods when performing machining such as.

[0002]

2. Description of the Related Art Conventionally, a playback type robot has been used to supply a plate material to a plate material processing machine such as a press brake,
It is known to take out after processing (JP-A-59-59).
175968). At that time, the robot carries one by one on the conveyor and holds the positioned works, or one by one from the top of the pile of stacked works, and transfers them to the processing machine. The work may shift in the middle. Therefore, in the case of the conventional press brake, positioning is performed by pressing the rear end of the work against the back gauge. On the other hand, Japanese Patent Examinations 5-63
No. 250 and Japanese Examined Patent Publication No. 5-63251 disclose a positioning method in which a pair of sensors are provided on the left and right of a back gauge to feed back data to the robot whether to rotate the work horizontally or to move it forward. There is. Further, in order to perform accurate and stable positioning, it is also known to employ an abutting gauge with a roller (see Japanese Utility Model Laid-Open No. 3-68720), or to provide a back gauge with a sensor capable of measuring the contact of a workpiece. (Japanese Patent Laid-Open No.
-159189 gazette).

[0003]

In the above-mentioned conventional method, it is necessary to provide a back gauge with a plurality of detecting portions, so it is necessary to modify the plate material processing machine side such as the press brake.
Moreover, there is a problem that the positioning accuracy originally possessed by the back gauge is impaired. Furthermore, since the plate material processing machine side and the robot side exchange information, the assembly and adjustment work of the control system is complicated. In addition, since the correction operation of positioning is limited to straight movement and horizontal rotation, there is a problem that the working work and the range of application of the work are narrow. The present invention has been made to solve the problems of the conventional positioning method, and enables the robot to complete the positioning control system as much as possible, thereby reducing the modification work on the plate material processing machine side and reducing the back gauge. It is a technical object to provide a position detection method, a positioning method and a device that do not require additional work. Further, it is a technical object of the present invention to provide a positioning method and device applicable to a wide range of machining operations and works.

[0004]

A method for detecting a position of a work by an industrial robot according to the present invention comprises: (a) a work and a hand or arm of the industrial robot holding the work within a predetermined range. Process of making the workpiece relatively movable according to the force from the workpiece and gripping the workpiece by a hand portion provided with a detecting portion for detecting the movement state, (b) a positioning member of the plate processing machine of the counterpart To the right position, (c) a step of detecting the relative movement state of the work and the hand part or the arm part by the detection part, (d) a correct position of the work based on the data detected by the detection part. And a step of determining whether or not it is present.

In such a position detecting method, if a detector for detecting the presence or absence of movement is adopted as the detector,
In step (c), the presence or absence of relative movement can be detected, and in step (d), when there is no movement, it can be determined that the position is correct.

Further, if a detector that detects whether or not the amount of movement is within a predetermined range is adopted as the detection unit, the presence or absence of movement and whether or not the movement is within a predetermined range in the step (c). In step (d), it is determined that the position is correct when there is movement within a predetermined range, and when there is no movement or when the amount of movement exceeds the predetermined range, it is determined that the position is not correct. be able to.

In the work positioning method of the present invention, when the position of the work is detected by the above detection method, and when it is determined that the position is not correct, the hand portion or arm portion is moved based on the detected data to move to the required position. It is characterized by making corrections. When detecting the position based on the presence or absence of movement, when it is determined that the work is not in the correct position, the position is corrected by a small distance, the correctness of the position is detected again, and the position correction and detection are performed until the correct position is reached. A method of repeating can be adopted. Further, when the number of repetitions exceeds a predetermined value, it may be judged as an error and the operation may be stopped. When processing a plurality of works with a plate material processing machine, it is preferable to perform learning control for correcting the transport position of the next work based on the position correction data of the previous work.

The work position detecting apparatus according to the present invention comprises: (a) a work or a hand portion which is provided between a work and a hand portion or an arm portion of an industrial robot which holds the work according to an external force. Whether the work position is correct based on the mechanism for relatively moving within the range of (b), (b) the detection unit provided on the arm or hand for detecting the movement state, and (c) the data from the detection unit. It is characterized by comprising a means for judging whether or not.

The work positioning device of the present invention comprises the work position detecting device and means for causing the industrial robot to correct the work position required according to the judgment. The detection unit preferably includes a pair of two sensors that detect movement of the work in at least two directions.

[0010]

In the position detecting method, the positioning method and the apparatus of the present invention, since the detecting portion is on the robot side, no additional work or wiring work is required for the plate material processing machine. That is, the robot side hand portion or arm portion is provided with a portion that relatively moves according to the force of the workpiece when the workpiece comes into contact with the positioning member, and a detection portion that detects the movement.
The reaction force applied to the positioning member is used to obtain the data regarding the appropriateness of the position and the data regarding the operation to be corrected. Therefore, the detection unit is on the robot side, the control system can be completed on the robot side, there is no need to perform modification work on the plate material processing machine side, and there is no additional work on the back gauge etc. to reduce accuracy. .

[0011]

Embodiments of the method and apparatus of the present invention will now be described with reference to the drawings. FIG. 1 is a side view showing an embodiment of a positioning device of the present invention, FIG. 2 is a perspective view showing the whole of a robot and a processing machine equipped with the device, and FIGS. 5 is a flow chart showing another embodiment of the method of the present invention in that order, and FIG. 7 is a perspective view showing another embodiment of the detection unit relating to the apparatus of the present invention. is there.

1 and 2, the press brake 20 is of a type in which an elevating and lowering die 22 moves up and down with respect to a fixed upper die 21, and hydraulic pressure is applied after an end portion of a plate member 13 is inserted between the upper and lower die. Bending is performed by raising the lower die 22. The lower mold may be fixed and the upper mold may be moved up and down, or the upper and lower molds may be moved to face each other. Reference numeral 24 in FIG. 1 is a stopper (positioning member) for abutting and positioning the plate member 13. The robot 1 shown in FIG. 2 is fixedly supported on the floor by a support base 2, and the output shaft (horizontal rotation shaft) 3A of the first motor with reduction gear fixed to the upper part of the support base 2 is above the press brake 20. Mold long axis 21A
Alternatively, they are arranged so as to coincide with the lower mold major axis 21B.

Next, the output shaft 3A is provided with a first right-angle actuating arm 4 extending in a direction perpendicular to the output shaft 3A and the upper die long shaft 21A, and further attached to the tip of the first right-angle actuating arm 4. A second right-angle actuating arm 6 is attached to the output shaft (horizontal rotation shaft) of the second motor 5 with a reduction gear that is fixed. A third speed reducer motor 7 is fixed to the tip of the second right angle actuating arm 6, and a horizontal actuating arm 8 reaching the vicinity of the center of the press brake 20 is attached to the output shaft of the third reducer motor 7. The first and second actuating arms 4, 6 and the horizontal actuating arm 8 are
Each drive motor can rotate at an arbitrary angle.

A fourth motor 9 with a reduction gear is attached to the tip of the parallel operating arm 8 at a right angle to the parallel operating arm 8, and a base 12 is attached to its output shaft 10. The base 12 is provided with a suction head 11 for holding the plate member 13 in parallel with the base 12 so as to be movable back and forth within a certain range with respect to the press brake 20. The suction head 11 and the base 12 are movably combined so as to be passively displaced when a predetermined external force is applied, and a return spring 12a for returning the suction head 11 and the base 12 to the original position is interposed therebetween. There is. Further, a sensor S1 for detecting the presence or absence of movement between the two
S2 is provided as a left and right pair as shown in the second. The sensors S1 and S2 may be a contact type such as a pressure switch, or may be a non-contact type such as a proximity switch. Reference numeral 14 in FIG. 2 is a processed product.

The robot 1 has a control box 15 having a built-in computer in addition to the above machine parts, and the control box is shown in FIG.
As shown in FIG. 3, the signals from the sensors S1 and S2 are received to control the motors 3, 5, 7, and 9 according to a program.

In FIG. 1, reference numeral 30 is a computer unit, and this computer unit 30 is a central processing unit for arithmetically processing work condition data (such as the number of pieces processed and the number of sheets loaded) and robot motion data (such as speed and movement amount). (CP
U), a random access memory (RAM) for storing data in the middle of calculation or a program that has been taught in, a read only memory (RO) for storing a basic program
M) and the like. These data are input / output unit 31
It is input from the outside through and output to the outside. The motor drivers 33, 35, 37, 39 receive the output signals from the computer section 30 and convert the electric power so as to operate the motors 3, 5, 7, 9 of the respective shafts with reduction gears. The signals from the sensors S1 and S2 are also taken into the computer unit 30 through the input / output unit 31.

The teaching box 32 is for moving the robot 1 by a manual operation, and the data of the moving amount is stored in the computer unit 30 while the robot performs a required operation by the manual operation. Reference numeral 40 is the press brake 2
It is a press brake control device for sending an operation signal to 0.

In the robot 1 having the above structure, the base 1 for supporting the suction head 11 so as to allow movement by an external force.
2 and the sensors S1 and S2 for detecting the amount of movement thereof and a part of the computer section 30 constitute the position detecting device of the present invention. The stopper 24 that abuts the plate member 13 is also indispensable as a prerequisite for the position detection device to operate. Further, the position detecting device and a mechanism for driving the suction head 11 of the robot 1 constitute a positioning device. Robot 1 and press brake 20 configured as described above
The overall operation is almost the same as the conventional one. That is, as shown in FIGS. 4 and 5, the plate member 1
The plate materials 13 are lifted one by one from the stack of No. 3 by the suction head 11 (step 110, FIG. 3A), and the suction head 11 is moved.
180 ° while raising the angle (Step 12
0), while firmly holding the plate material 13 from below, insert it between the upper and lower molds of the press brake 20 (step 13).
0, Figure 3b).

Then, in this state, as shown in FIG. 1, the first motor 3 and the second motor 5 are synchronously rotated according to a program to advance the plate material 13 in the direction of arrow A by a predetermined distance (step 140). Then, the sensors S1 and S2 detect whether or not the plate member 13 has hit the stopper 24 when the forward stroke is completed. Then, the computer unit 30 determines whether or not both sensors S1 and S2 have detected (step 150). If normal, the processing start signal is sent to the press brake 20 as it is, and processing is performed (step 170, FIG. 3c). ). And after processing is completed, finished product 1
4 are stacked in the finished product stack (step 180, FIG. 3d).

On the other hand, depending on the detection data, one of
Alternatively, when it is determined that the positioning correction is necessary because both sensors S1 and S2 have not detected, the correction method is calculated (step 160), and the horizontal direction (arrow A) is calculated.
If the correction in the (-B direction) is required, a correction signal is sent to the first, second, and third motors 3, 5, 7 to move the motor forward, and if correction of rotation in the horizontal plane is required, the fourth motor 9 is performed. Forward and reverse rotations are commanded and rotated (steps 160 and 140). Then, after the correction, the position is detected again (step 150), the above detection / correction is repeated until the correct position is reached, and then the above-described processing and take-out process is performed (step 17).
0,180,190, see FIGS. 3c and 3d). Whether the correction of the rotation direction is appropriate or not is determined by the pair of left and right sensors S1,
It can be detected by detecting only one of S2. In the detection / correction process, if the number of repetitions exceeds the number in a predetermined range, the process can be stopped immediately without correction (step 200).

The above-mentioned cycle is to detect every time, but if it is corrected every time, the cycle time becomes long, and it is disadvantageous in maintaining accuracy due to variations. Therefore, it is preferable to rewrite the teach-in data in advance based on the above detection result, and to make the robot operate based on the rewritten data, so-called learning control is performed.

The flow charts of FIGS. 5 and 6 show an embodiment of learning control when the four sides of a rectangular work are bent in order. It should be noted that the step of inserting the work from the holding of the work between the upper and lower dies and the stack for taking out the processed product are omitted, and only the main part is shown. The symbols X, Y, A, B
Indicates the position data of the X coordinate, the Y coordinate of the robot, the horizontal angle of the hand, and the turning angle of the hand, respectively.
Each of p, Yp, Ap, and Bp represents the first taught position, and Xdi, Ydi, Adi, and Bdi represent respective offset data, that is, the difference between the correct position and the taught position. The symbol i indicates which side of the four sides is processed.

When the operation of moving from the previous point toward the stopper is started (step 210), first, which side of the learning data is used is selected (step 220). Then, it is selected whether to use the learning data or to ignore it and clear it (step 230). It is cleared when machining a new shape work is started (step 240).

Next, the number of times the correction / detection operation is repeated for the work is counted, and when it is repeated a predetermined number of times (judgment value, for example, 10 times) or more, error detection ER for performing error processing is performed. That is, first, the data is cleared (step 250), and when the number of repetitions exceeds the judgment value, "1" is added to the counter and the process proceeds to the next step. When it exceeds, error processing such as stopping the machine is performed (step 275).

Next, the teaching position data Xp, Yp, A
Offset data Xdi, Ydi, Adi,
A calculation for adding Bdi is performed (step 280), and the suction head is moved according to the new data X, Y, A, B (step 290). Then, the sensor determines whether or not the new position is correct (step 300). If the position is correct, the abutting operation is ended (step 310) and the process proceeds to the next point. If the position is not correct, a predetermined value, for example, "-1.0" is added to the offset data, the number of repetitions is determined, and the movement is performed using new data. In this way, the detection and the movement are repeated until the correct position is reached, but the offset data is stored as the contact learning data and is used when the same side is machined for the next work. This eliminates the need for repeated detection and correction from the next work.

If the cause of the offset is that the suction head is gripping a position deviated from the center of the work, for example, the data on the right short side (i = 1) is converted to the left short side (i = 1). = 2), and the data of the front long side (i = 3) can be used by reversing the positive / negative when processing the back long side (i = 4).

When the cause of the offset is the bending of the work, it is considered that the offset amount of the left short side or the front long side is the same as the offset amount of the right short side or the rear long side. The number of repetitions can be significantly reduced by adding the same to the above and processing.

Next, another embodiment of the detecting section in the apparatus of the present invention will be described. In the embodiment shown in FIG. 1, sensors S1 and S2 for detecting when the suction head 11 moves in the direction of arrow B with respect to the base 12 are provided, but when four sides of the work are bent, as shown in FIG. In addition, the sensors S3, S4, S5, which detect when moving in the opposite direction (direction of arrow A) and in the direction of arrows CD perpendicular to them, are detected.
S6, S7 and S8 are provided. Note that the suction head 11 does not need to substantially slide with respect to the base 12, and if the sensor can detect that the plate material 13 has hit the stopper 24, for example, the suction deformation of the suction head 11 due to elasticity can be performed. And so on. "Movement" in claims 1 and the like is a concept including such bending deformation.

On the contrary, the suction head 11 may be slid sufficiently with respect to the base 12 and the "correct position" may be determined only when a predetermined amount of movement is detected. At this time, if a sensor for detecting the movement amount is adopted, the offset amount can be rewritten with the data of the movement amount.

[0029]

According to the position detecting method of the present invention, it is not necessary to carry out a large-scale additional work on the processing machine side, and the control system can be completed only by the robot side, which is an advantage that it can be easily applied to existing equipment. is there. Further, the positioning method of the present invention,
Since detection and position correction can be performed only on the robot side, high positioning accuracy can be easily achieved. The position detecting device and the positioning device of the present invention can be easily installed on the hand part of an existing robot.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of a positioning device of the present invention.

FIG. 2 is a perspective view showing an entire robot and processing machine equipped with the apparatus of FIG.

FIG. 3 is a process drawing showing an embodiment of a positioning method of the present invention.

FIG. 4 is a flowchart showing an embodiment of the positioning method of the present invention.

FIG. 5 is the first half of a flowchart showing another embodiment of the positioning method of the present invention.

6 is the latter half of the flowchart of FIG.

FIG. 7 is a perspective view showing another embodiment of the detection unit related to the device of the present invention.

[Explanation of symbols]

 S1 sensor S2 sensor 1 robot 15 control box 20 press brake

Claims (10)

[Claims] 1. A method for detecting the suitability of the position of a work when the work is supplied to a plate material processing machine by an industrial robot, comprising: (a) the work and a hand portion or arm of the industrial robot holding the work. And (b) gripping a work by a hand unit provided with a detection unit that detects a movement state of the work, while allowing relative movement between the work unit and a unit within a predetermined range according to an external force. The process of advancing the work to the positioning member of the mating plate machine,
(C) A step of detecting the relative movement state of the work and the hand part or the arm by the detection part, (d) Based on the data detected by the detection part, it is determined whether or not the work is in the correct position And a work position detecting method comprising: 2. The detection unit detects the presence or absence of movement, detects the presence or absence of relative movement in the step (c), and corrects the position when there is no movement in the step (d). The detection method according to claim 1, wherein it is determined that it is not, and when it is moved, it is determined that it is in the correct position. 3. The detection unit detects whether or not the amount of movement is within a predetermined range, and determines whether or not there is movement in step (c) and whether or not the movement is within a predetermined range. Detecting, in the step (d), when there is a movement within a predetermined range, it is determined as a correct position, when there is no movement or when the amount of movement exceeds a predetermined range, it is determined that the position is not correct The detection method according to item 1. 4. When the position of the work is detected by the method according to claim 1, 2 or 3, and when it is determined that the position is not correct, the hand portion or arm portion is moved based on the detected data to obtain a necessary value. Positioning method for position correction. 5. The method according to claim 4, wherein when it is determined that the workpiece is not in the correct position, the position is corrected by a slight distance, the suitability of the position is detected again, and the position correction and the detection are repeated until the correct position is reached. the method of. 6. The method according to claim 5, wherein when the number of repetitions exceeds a predetermined value, it is judged as an error and the operation is stopped. 7. The method according to claim 4, wherein when a plurality of workpieces are processed by a plate material processing machine, the transport position of the next workpiece is corrected based on the position correction data of the previous workpiece. 8. (a) It is provided between a work and a hand part or arm part of an industrial robot holding it.
A mechanism for relatively moving the work or the hand part within a predetermined range according to an external force; and (b) a detection part provided on the arm part or the hand part for detecting the movement state,
(C) A work position detecting device comprising means for judging whether or not the work position is correct based on the data from the detection section. 9. A work positioning device comprising: the work position detecting device according to claim 8; and means for causing an industrial robot to correct a work position required according to the judgment. 10. The detection unit includes at least two workpieces.
An apparatus according to claim 8 or 9, comprising a pair of sensors for detecting movement in a direction.