JPH022674B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention particularly relates to a position correction system for a conveyance device in which a robot arm is mounted on a conveyance vehicle, and the robot arm is used to carry workpieces into and out of a machine tool and to change tools. It is related to the device.

An object of the present invention is to enable accurate work to be performed on a machine tool regardless of positional deviation of the machine tool and positioning error of the carrier.

A self-propelled conveyance device with a robot arm mounted on a conveyance vehicle positions the conveyance vehicle at a position corresponding to each machine tool when a proximity switch installed on the conveyance vehicle detects a metal plate placed on the floor. As a result, it is not possible to obtain a very high fixed-position stopping accuracy, and the installation position of the machine tool also varies from machine to machine, making it difficult to properly position the transport vehicle relative to the machine tool. For this reason, conventionally, a conical positioning cone is installed on the floor surface where the transport vehicle is to be stopped. A positioning member for positioning and a cylinder for raising and lowering the positioning member were provided. In this method, it is necessary to configure each machine tool so that the position of a plurality of cones can be adjusted in three dimensions, and to perform position adjustment for each cone, which has the problem of requiring a large amount of time for the adjustment work.

The present invention solves the above conventional problems,
The feature is that when the transport vehicle is stopped, the relative position between the machine tool and the transport vehicle is detected, and the robot's working part is corrected to the appropriate position relative to the machine tool in response to this detection signal. That's true.

Embodiments of the present invention will be described below based on the drawings.
In FIG. 1, reference numeral 1 denotes a transport vehicle, which has wheels 12 and is self-propelled. A robot 2 is mounted on this carrier 1. The positioning robot 2 has a rotation base 3 that rotates in the θ direction around a vertical axis by a θ-axis servo motor 4, and a rotation base 3 that rotates within a vertical plane passing through the rotation axis of the rotation base 3. An intermediate arm 5 is mounted so that it can be rotated by a servo motor 6 for the L axis, and a servo motor 8 for the β axis is pivotally attached to the tip of the intermediate arm 5 so that it can rotate in a vertical plane. a support arm 7 that rotates;
It consists of a gripping claw 11 that can be opened and closed on a support box 9 attached to the tip of the support arm 7, and is attached to be rotatable around a vertical axis via a rotation block 10 by an ω-axis servo motor 32.
The posture of the support box 9 is controlled by a chain and sprocket mechanism (not shown) so that even when the intermediate arm 5 and the support arm 7 are rotated, the gripping claws 11 are always in a vertical state.

On the other hand, on the floor surface on which the positioning carriage 1 moves, a guiding cable 13 for guiding the carriage 1 to the corresponding position with each machine tool 17 and a metal plate 16 are arranged at the stop position corresponding to the machine tool 17. Transport trolley 1
is provided with a proximity switch 15 for detecting the metal plate 16. The induction cable 13
gives operation commands from a central computer to the transport vehicle 1, serves as a reference for a predetermined moving route of the transport vehicle 1, and transmits operation commands to the robot 2.

The machine tool 17 is provided with a reference plate 18 on the side where the transport vehicle 1 stops, and a reference plate 18 is provided on the side where the transport vehicle 1 stops.
A position detecting head 19 and a position detecting rod 29 which are mated with this reference plate 18 are provided. These specific structures will be explained with reference to FIGS. 2 and 3.

The reference plate 18 on the machine tool 17 side is provided so as to be movable forward and backward by the guide of a pilot bar 23 which is slidably held by a support sleeve 22, and is actuated by a cylinder (drive device) 24 for advancing and retracting the reference plate. It's summery. This reference plate 18
A vertical reference magnet generating body 27a and a horizontal reference magnet generating body 27b are provided on the front surface of the frame.

On the other hand, the position detection head 19 on the side of the transport vehicle 1 is supported by a support base 20 by a pilot bar 21 so as to be movable back and forth, and is always pushed in the forward direction by a push shaft 25 and a spring 26. A vertical deviation detector 28a corresponding to the vertical reference magnet 27a is provided on the front surface of the position detection head 19.
and a horizontal direction deviation detector 28b corresponding to the horizontal direction reference magnetic generator 27b, and the vertical direction deviation detector 28a and the horizontal direction deviation detector 28 are provided.
b constitutes a second detection device that detects a deviation in a direction perpendicular to the moving direction of the reference plate 18. Further, the position detection rod 29 is arranged so as to be able to move forward and backward at a position where it abuts against the front surface of the reference plate 18, and is constantly pushed in the forward direction by a spring 30. A differential transformer (first detection device) 31 is provided at the rear end of the position detection rod 29 for detecting the amount of deviation of the transport vehicle 1 in a direction perpendicular to the traveling direction.

The differential transformer 31 including the vertical reference magnet generating body 27a, the horizontal reference magnet generating body 27b, the corresponding vertical deviation detector 28a, the horizontal direction deviation detector 28b, and the detection rod 29 is connected to the machine tool 1.
The amount of relative shift of the transport vehicle 1 with respect to the reference point is detected using + and - output voltages with the reference point as the center.

The operation of the above device of the present invention will be explained. The self-propelled transport vehicle 1 guided by a command signal from the guidance cable 13 detects the metal plate 16 at a position corresponding to the machine tool 17 using the proximity switch 15, stops traveling, and positions it. This transport vehicle 1
After positioning, the cylinder 24 for advancing and retracting the reference plate
is actuated to move the reference plate 18 to the forward end and protrude toward the transport vehicle 1 side. As the reference plate 18 moves forward, the position detection head 19 and the position detection rod 29 come into contact with the front surface of the reference plate 18, and both move backward. As a result, the vertical reference magnetizing body 27a and the horizontal reference magnetizing body 27b on the reference plate 18 side are closely matched with the vertical direction deviation detector 28a and horizontal direction deviation detector 28b on the position detection head 19 side, and the position The movable element of the differential transformer 31 at the rear end of the detection rod 29 is displaced by the amount that the position detection rod 29 moves backward. The above-mentioned vertical deviation detector 28
In a, the amount of vertical deviation of the carrier 1 with respect to the machine tool 17 is detected, and the horizontal deviation detector 28b detects the amount of horizontal deviation of the carrier 1 with the output voltage. In this case, the amount of deviation in the direction perpendicular to the traveling direction of the transport vehicle 1 is detected using the output voltage. Then, each servo motor 4, 6, 8, 32 of the robot 2 is controlled based on the detection signal of each of these deviation amounts, and the gripping claw 11 is
This is to correctly correct the position of the machine tool 17 to an appropriate position for the machine tool 17, that is, a workpiece loading/unloading position or tool replacement position.

Control of the above-mentioned conveying device will be explained with reference to the circuit diagram of FIG. 40 is a computer installed in the transport vehicle 1, and 41 is a memory in which a program for causing the robot 2 to process each machine tool is incorporated.

An operation command signal from the central computer of the induction cable 13 is detected by the detection circuit 42 and inputted to the computer 40, and the computer 40 is input to the control circuit 46.
Commands are transmitted to control the traveling motor of the transport vehicle 1, the opening/closing control of the gripping claws 11, etc. The vertical deviation detector 28a, the horizontal deviation detector 28b, and the differential transformer 31 are connected to a computer 40 via a multiplexer 43 and an AD (analog digital) converter 44, and each detector 28a, 28b and differential transformer The output voltages of the positional deviation signals from 31 are sequentially switched, converted into digital data by an AD converter 44, and input to the computer 40. The corrected movement amount of the robot 2 is calculated based on each positional deviation signal inputted to the computer 40, and a corrected pulse is outputted to the drive unit 45 of each servo motor 4, 6, 8, 32. ，
8, 32, the rotation base 3, intermediate arm 5,
By operating the support arm 7 and the gripping claw 11, the gripping claw 1
The position of robot 1 is corrected to an appropriate position with respect to machine tool 17, and then robot 2 is caused to perform work such as loading and unloading workpieces to machine tool 17 or exchanging tools based on the program in memory 41.

The above corrected movement amount is calculated by the positional deviation detectors 28a, 28
This is the amount of movement for correcting the gripping claw 11 of the robot 2 so that this offset is offset based on the amount of positional deviation on the orthogonal coordinates detected by the differential transformer 31. A corrected rotation amount on the positional shift amount θ to ω axis is calculated, and correction is performed based on this. Therefore, after the corrective movement, the position of the gripping claws 11 with respect to the machine tool 17 is always constant, and the workpiece can be loaded and unloaded reliably.

As described above, according to the present invention, after positioning the transport vehicle with respect to the machine tool, the amount of relative positional deviation of the transport vehicle with respect to the machine tool is detected, and this detection signal is used to direct the working part of the robot to the machine tool. Since it corrects the position to the appropriate position, it is possible to have the machine tool perform accurate work regardless of the positional deviation of the machine tool or the positioning error of the transport vehicle. This has the effect of eliminating the need for a positioning cone, a means for positioning the carriage at a fixed position relative to the machine tool using this cone, and a large amount of time for position adjustment work. Further, the reference plate is horizontally moved by a predetermined amount toward the transport vehicle side, and the first detection device detects the amount of backward movement of the position detection rod that is moving backward by this reference plate, and the reference plate and position detection head that are in contact with each other are detected by the first detection device. Since the reference member and the second detection device are provided in the structure, it is possible to accurately detect the deviation of the carriage relative to the machine tool with a simple structure. Further, when moving the carrier, the reference plate is moved backward, so that there is no possibility that the carrier will interfere with the reference plate.

[Brief explanation of drawings]

Fig. 1 is a front view of the device of the present invention, Fig. 2 is an enlarged sectional view taken along the line of Fig. 1, Fig. 3 is an enlarged view of the detection state in Fig. 2, and Fig. 4 is a control circuit diagram of the device of the present invention. be. DESCRIPTION OF SYMBOLS 1... Transport vehicle, 2... Robot, 3... Swivel base, 4... Servo motor, 5... Intermediate arm, 6... Servo motor, 7... Support arm, 8
... Servo motor, 9 ... Support box, 10 ... Rotating block, 11 ... Gripping claw, 14 ... Floor surface, 13
... Induction cable, 15 ... Proximity switch, 16
...Metal plate, 17...Machine tool, 18...
Reference plate, 19...Position detection head, 27a
...Vertical reference magnet generating body, 27b...Horizontal reference magnet generating body, 28a...Vertical direction deviation detector, 28
b...Horizontal displacement detector, 29...Position detection rod, 31...Differential transformer.

Claims (1)

[Claims] 1. By moving the transport vehicle with the robot attached to the position corresponding to the machine tool, and moving the working part at the tip of the robot in a three-dimensional direction, the workpiece can be carried in and out of the machine tool, or tools can be replaced. The machine tool is provided with a drive device that supports a reference plate on the machine tool so as to be horizontally movable toward the carrier vehicle side, and horizontally moves the reference plate by a predetermined distance toward the carrier vehicle side, The transport vehicle supports a position detection head and a position detection rod that contact the reference plate so as to be movable in the same direction as the movement direction of the reference plate. A first detection device for detecting is provided on the conveyance vehicle, a reference member and a second detection device for detecting a deviation in a direction perpendicular to the moving direction of the reference plate are respectively provided on the reference plate and the position detection head, and the first detection device is provided on the reference plate and the position detection head. A position correction device for a conveying device, characterized in that it is provided with a correction means for correcting the position of a working part provided on a robot to an appropriate position with respect to a machine tool in accordance with detection signals from a detection device and a second detection device. .