JPS63251179A - Stoppage positioning device for robot movable truck - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a stop positioning device for a robot movable trolley that moves between multiple points while being guided by rails, and in particular to a robot movable trolley with improved positioning accuracy. The present invention relates to a stop positioning device.

[Prior Art] Conventionally, there has been known an industrial robot shown in FIG. 4 that moves back and forth between machine tools and the like installed at two distant locations while being guided by rails to transfer and perform work. In this figure, reference numeral 1 denotes a rail base, which is installed in front of a machine tool 2.3 installed at a distance of several meters to several lθ meters. On the upper surface of this rail base l, a V-shaped rail 1a having a 7-shaped upper portion and a flat rail 1b having a flat upper surface are arranged in parallel. Further, 5 is a robot, which is mounted on a movable trolley 4 that moves within a V-shaped rail la and a flat rail lb+. The robot 5 is configured to remove a workpiece (path shown) processed by the machine tool 2 from the machine tool 2 and mount this workpiece on the machine tool 3. Further, as shown in FIG. 5, on the back side of the moving trolley 4, V-shaped wheels 5a and 5b, which are wheels having V-shaped grooves and which move on the V-shaped rail la, are provided. Flat wheels 6a and 6b rolling on flat rails Ib are arranged, one end of the shaft 7a is located at the center of the wheel 5a, and one end of the shaft 7a is located at the center of the wheel 6a.
The other end of the shaft 7b is attached to the center of the wheel 5b, and the other end of the shaft 7b is attached to the center of the wheel 6b. These shafts 7a and 7b are rotatably attached to the back surface of the moving trolley 4.

Further, a gear device IO is provided approximately at the center of the shaft 7b, and the tip of the shaft 9a of the drive motor 9 is connected to the gear device IO. In addition, the wheels 6a of the moving trolley 4 and the wheels 6
A rubber wheel 11 that rolls on the flat rail Ib is arranged at a position approximately midway between the flat rail Ib and the flat rail Ib. The center of this rubber wheel 11 is attached to the rotating shaft of an encoder 12, and the encoder 12 outputs a pulse signal in proportion to the number of rotations of this rubber wheel 11. This pulse signal is a counter (as shown)
When the count of the counter reaches the number of pulses proportional to the distance from the stop position of the machine tool 2 to the stop position of the machine tool 3, a stop signal is sent from the control circuit (path shown) to stop the drive motor 9. is generated, and the drive motor 9 is controlled to stop.

In the above configuration, when transferring the workpiece processed by the machine tool 11wc2 to the machine tool 3, the robot 5 first removes the processed workpiece from the machine tool 2, grips it, and lifts it from the machine tool N1wc2, and then the robot 5 The motor 9 is driven. Thereby, the shaft 7b is rotated via the gear device IO, and the wheels 5b, 6b are rotated. As a result, the moving trolley 4 is moved to the rail 1a,
Guided by I b, they begin to move. Further, as the moving trolley 4 moves, the rubber wheels 11 roll on the flat rail Ib. When the rubber wheel 11 rotates, a pulse signal is supplied from the encoder 12 to the counter in proportion to this rotation.

This pulse signal is counted by a counter, and when a predetermined number of pulses is counted, that is, when the movable cart 4 moves a predetermined distance from the front of the machine tool 2 and reaches the front of the machine tool 113, the control circuit drives the The motor 9 is controlled to stop, and the moving cart 4 is stopped in front of the machine tool 3. At this position, the robot 5 is driven and the transferred workpiece is mounted on the machine tool 3. Next, the workpiece is processed by the machine tool 3.

[Problems to be Solved by the Invention] In the conventional apparatus described above, the stopping place of the robot 5 is determined by determining the moving distance from the number of rotations of the rubber wheels 11, and then controlling the moving trolley 4 to stop. By the way, when the moving distance of the moving trolley 4 is long, slipping may occur between the rubber wheels 11 and the flat rail lb while the moving trolley 4 is running, or the flat rail 1b may slip due to changes in environmental conditions such as temperature. When the rubber wheels 11 expand and contract, there is a problem that an error occurs between the number of rotations of the rubber wheels 11 and the distance traveled, and the stopping position of the moving trolley 4 gradually shifts, causing trouble in the work of the robot.

Therefore, it is conceivable to move the moving trolley 4 using a linear pulse motor with good stopping position accuracy, but in this case, there is a problem in that the cost is high, especially when the moving distance is long.

This invention has been made in view of the above circumstances, and its purpose is to improve the accuracy of the stopping position of a mobile cart regardless of the slippage of the rubber wheels 11 or the expansion and contraction of the rails, and without incurring any cost. An object of the present invention is to provide a device for stopping and positioning a robot moving cart.

[Means for Solving the Problems] The present invention provides a reference position setting means for detecting that the robot movable trolley has passed a point separated by a predetermined distance from a stop position of the robot movable trolley; an encoder that generates a pulse signal in response to a moving distance of the robot; a counting unit that counts the pulse signals of the encoder from the time when the reference position setting unit detects passage of the robot mobile cart; and a counting result of the counting unit. The present invention is characterized in that it comprises a trolley stop control means for controlling the robot movable trolley to stop when the robot movable trolley reaches a predetermined value.

[Operation] According to the present invention, the stop position setting means detects that the robot movable trolley has passed a point a predetermined distance away from the stop position of the robot movable trolley, and the pulses generated by the encoder from this detection point onwards. When a predetermined number is counted, the moving trolley is controlled to stop. Therefore, compared to conventional devices that determine the position by counting the total travel distance, there is less error between the distance traveled from the reference position and the number of counts, and inexpensive equipment can be added to the conventional devices. It is possible to improve the stopping position accuracy by only using

[Example] Hereinafter, an example of the present invention will be described with reference to FIG. In this figure, parts that are the same as those in FIGS. 4 and 5 are given the same reference numerals, and their explanations will be omitted. In this figure, reference numeral 20 is a reference plate attached to the side of the rail base l, which is placed at a predetermined distance from the robot working position of the machine tool 3 to the machine tool 2 side, that is, the rubber wheel 11
The encoder 12 is arranged at a distance corresponding to 100 pulses of the pulse signal Sp generated from the encoder 12 in proportion to the rotation of the encoder 12. Similarly, a predetermined distance from the robot working position of the machine tool 2 to the machine tool 3 side, that is, the encoder 1
A reference plate 20 is also placed at a distance corresponding to 100 pulses of the pulse signal Sp generated by No. 2.

On the other hand, an optical interlayer 2I that detects this reference plate 20
is attached to the side of the moving trolley 4. The optical interrupter 21 includes an LED (light emitting diode) 22 and a photodiode 23 that receives light generated by the LED 22, and a gap S is provided between the LED 22 and the photodiode 23. This gap S is blocked by the reference plate 20. Further, this optical interrupter 2I supplies the optical detection signal So to the control circuit 24 shown in FIG. 2 when the gap S is not interrupted. In FIG. 2, the control circuit 24 controls the counter 3
The count data Sc of 0, the optical detection signal So of the optical ink club 21, and the control signal Sp from the control panel 25 are supplied, and the counter 30 receives a reset signal SQ1, and the drive circuit 26 receives a start control signal Sl, a deceleration control signal S2, and a stop control signal. 8
A control signal SN such as No. 3 is supplied. Further, the drive circuit 26 is a circuit that drives the drive motor 9, and drives the drive motor 9 according to a control signal SN supplied from the control circuit 24.

In the above configuration, for example, when transferring a workpiece processed by the machine tool 2 to the machine tool 3, the robot 5 is initially located in front of the machine tool 12, and the robot 5 is located in front of the machine tool 12, and This is indicated as a point P in the relationship diagram between speed V and travel distance.

First, the robot 5 removes the workpiece from the machine tool 2,
When gripped and lifted, the control circuit 24 supplies the activation control signal Sl to the drive circuit 26 .

As a result, the drive circuit 26 starts the drive motor 9,
The drive motor 9 rotates and the moving trolley 4 starts traveling. As the mobile trolley 4 travels, the rubber wheels 1
1 rolls on the rail tb, which causes the encoder 12
A pulse signal Sp is generated from. This pulse signal Sp
is supplied to the counter 30, and the counter 30 counts the number of pulses. Then, when a predetermined number of pulses are generated from the encoder I2 and the value counted by the counter 30 is supplied to the control circuit 24, the moving trolley 4 travels a predetermined distance and approaches the workpiece 4tal^3. (Then, a deceleration control signal S2 is supplied from the control circuit 24 to the drive circuit 26. As a result, the rotational speed of the drive motor 9 is gradually reduced, and the speed of the moving cart 4 is gradually reduced.

Then, as shown in FIG. 3, when the speed reaches the position of the reference plate 20 at a position where the speed has sufficiently decreased, the reference plate 20 blocks the gap S between the optical interlubrators 21. As a result, the light entering the photodiode 23 from the LED 22 of the optical interrupter 21 is blocked, and the photodetection signal So supplied to the control circuit 24 is turned off. As a result, the clear signal SI2 is supplied from the control circuit 24 to the counter 30, and the count of the counter 30 is cleared. The moving trolley 4 further travels, and the counter 30 starts counting the number of pulses of the pulse signal Sp supplied from the encoder 12 again. Then, when the moving trolley 4 further travels and the count reaches 100 pulses, that is, when the rubber wheels 11 rotate a predetermined number of times and reach the stop position Q shown in FIG. A stop control signal S3 is supplied to the drive circuit 26, the drive motor 9 is driven to stop, and the moving cart 4 is stopped. In this way, the robot 5 is accurately positioned at point Q shown in FIG. 3, that is, at a prescribed position in front of the machine tool 3. Next, the robot 5 attaches the transferred workpiece to the machine tool 3, and the workpiece is processed. Next, machine tool 3
When moving from the Q point in front of the machine tool 2 to the P point in front of the machine tool 2, the reference plate 20 installed on the machine tool 2 side is detected in the same way as above, and the movement trolley 4 is stopped in the same way as above. It is done. In this way, the above operations are repeated, and the robot 5 reciprocates between the machine tools 2 and 3 to perform work transfer work.

In the above embodiment, the reference plate 20 was installed at a predetermined position, and the reference plate 20 was configured to be detected by the optical interrupter 21 provided on the moving trolley 4. Instead of 21, a limit switch may be installed on the moving trolley 4, and a dog for hitting the limit switch may be installed at the reference position. Further, in the above embodiment, the reference plate 20 is detected by the optical interrupter 21 and then stopped at the position of 100 pulses, but the stopping position does not have to be at 100 pulses.

[Effects of the Invention] As explained above, according to the present invention, the stop position setting means detects that the robot movable trolley has passed a point a predetermined distance away from the stop position of the robot movable trolley, and The system is configured to count the pulses generated by the encoder from the time of detection, and control the moving trolley to stop when a predetermined number is counted, which is different from the conventional device that counts the traveling distance between each point and determines the stopping position. In comparison, stopping accuracy is improved, and positioning can be performed at low cost by simply adding inexpensive equipment to the conventional device.

[Brief explanation of the drawing]

Figures 1 (a) and (b) are side and front views showing the configuration of an embodiment of the present invention, Figure 2 is a block diagram showing the electrical configuration of the embodiment, and Figure 3 is a moving trolley. FIG. 4 is a perspective view showing the configuration of a conventional industrial robot, and FIG. 5 is a diagram showing the configuration of the back side of the moving trolley 4. l a, l b...Rail, 2.3...Machine tool, 4...Transfer trolley, 5...Robot, 9...Drive motor, 11...Rubber wheel, 12...・Encoder, 20... Reference plate, 21... Optical interlayer, 2
4...Control circuit, 26...Drive circuit, 30...Counter.

Claims (1)

[Claims] In the stop positioning device for determining the stop position of a robot mobile cart, on which a robot that performs various tasks is attached, and which travels while being guided by a rail installed between a plurality of work locations where the robots work, a reference position setting means for detecting that the robot movable trolley has passed a point separated by a predetermined distance from a stop position of the robot movable trolley; and an encoder that generates a pulse signal corresponding to the moving distance of the robot movable trolley. , a counting means for counting pulse signals of the encoder from the time when the reference position setting means detects passage of the robot movable trolley, and control to stop the robot movable trolley when the counting result of the counting means reaches a predetermined value. What is claimed is: 1. A stop positioning device for a robot movable cart, comprising a cart stop control means for controlling a moving robot.