JPS62203789A - Follow-up controller - 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 (Field of Industrial Application) The present invention uses an industrial robot installed on a follower cart that moves along the conveyor to follow the workpiece to remove parts from the workpiece being conveyed by a conveyor. The present invention relates to a follow-up control device designed to perform the following operations.

(Prior Art) On an automobile assembly line, in order to improve assembly efficiency, industrial robots are used to move following the movement of the automobile body as the workpiece is conveyed on a conveyor. is used to assemble parts onto the car body.

Figure 8 shows an automobile body as work W, which is conveyed to conveyor 1.
2 is a diagram illustrating an example of a follow-up device in which a rear window is assembled to an automobile body W by an industrial robot 4 installed on a follow-up cart 3 on a rail 2 laid along a conveyor 1 while being conveyed by a conveyor 1. . As a control device for controlling the movement of the follow-up cart 3 in such a follow-up device, the one shown in FIG. 9 has been developed. As shown in the figure, a workpiece W is placed on a workpiece truck 5 and transported by a conveyor 1 that constitutes an assembly line. As shown in FIG. 8, the work truck 5 is incorporated into the conveyor 1 and is conveyed by a chain 7 driven by a motor 6.

An endless side conveyor 8 made of a chain or belt is provided along the conveyor 1 over a predetermined length,
A workpiece position detection head 9 for capturing a characteristic portion a of the workpiece W is attached to the side conveyor 8.

When the workpiece position detection head 9 captures the workpiece W, the side conveyor 8 is operated, and the pulse generator 10 provided on the side conveyor 8 is driven. Based on the pulse count value generated by the pulse generator 10, the control means 11 determines the position of the workpiece carriage, that is, the workpiece W on the conveyor 1. On the other hand, the following cart 3 is moved on the rail 2 as a following means by a servo motor 12, and by counting the pulse count value from the servo motor 12 in the control means 11, the following cart 3 is moved by a servo motor 12. The position on the rail 2 is detected. In this way, the position of the workpiece W on the conveyor 1 is determined, and the position of the follower cart 3 on the rail 2 is determined, so in order to correct the deviation from the positional deviation between the two, the servo motor A command voltage signal is sent to 12. As a result, the follower truck 3 follows the workpiece truck 5, that is, the work W, and the industrial robot 4 provided on the follower truck 3 assembles parts P, such as a rear window, onto the automobile body W while following the workpiece truck 5.

(Problems to be Solved by the Invention) However, in the above-mentioned follow-up control device, the pulse generator 10 is driven by a chain or a belt, etc., via a chain or belt conveyor 8 to detect the workpiece position. Therefore, due to elongation or deflection of the chain or belt, the pulse count of the pulse generator 10 for one shift will include an error corresponding to the elongation or deflection with respect to the position of the workpiece W, making it impossible to track with high precision. There was a problem with that.

The present invention corrects workpiece position information obtained by a workpiece position detection means such as a pulse generator with absolute position information of the workpiece relative to the conveyor obtained by an absolute position detector installed adjacent to the conveyor. The purpose is to enable a tracking cart to follow a workpiece with precision.

(Means for Solving the Problems) To achieve the above object, the present invention provides a follow-up means for conveying a follow-up cart along the work cart, adjacent to a conveyor for transporting a work cart on which a work is supported. and a work means for performing a predetermined work on the work on the follow-up cart, the workpiece position detection means being driven by the conveyor to detect the position of the work on the conveyor; a following cart position detection means for detecting the position of the following cart in the following means based on a signal from a motor that drives the cart; a calculation means for calculating a positional deviation between the workpiece and the conveyor, a commanding means for sending a signal to the motor to correct the deviation, and an absolute position detector installed adjacent to the conveyance means to detect the absolute position of the workpiece with respect to the conveyor. a comparison calculation means for comparing the absolute position signal of the workpiece from the absolute position detector and the workpiece position signal from the position detection means; This is a follow-up control device having a correction means for sending a signal.

(Function) The position of the workpiece relative to the conveyor is detected by the workpiece position detection means, while the position of the follower cart relative to the follower means is detected by the follower cart position detector, and the follower cart moves to correct these positional deviations. That will happen. Then, the absolute position of the work relative to the conveyor is measured by the absolute position detector, and the position information of the work from the work position detecting means is corrected or corrected by the position information from the absolute position detector. This improves the accuracy of the position followed by the tracking cart, making high-precision tracking possible.

(Example) Next, the present invention will be explained with reference to the accompanying drawings.

In addition, the same reference numerals are given to the parts common to the parts in FIG. 8.9.

FIG. 1 is a block diagram showing the basic structure of a follow-up control device according to an embodiment of the present invention.
The position above is detected by the workpiece position detection means (pulse generator>10).On the other hand, the position within the following means (rail) 2 of the following cart 3 is detected by the signal from the servo motor 12 that drives the following cart 3. Tracking trolley position detection means 2
Detected by 0. These positional information are calculated by calculation means 2.
1, and the positional deviation between the workpiece W and the follow-up cart 3 is calculated. In order to correct the deviation determined by the calculation means 21, a correction signal is fed back from the command means 22 to the servo motor 12.

Further, the position information from the absolute position detector 23 for detecting the absolute position of the workpiece W on the conveyor 1 and the signal from the workpiece position detection means 10 described above are compared in the comparison calculation means 24, and the Correction of the position information from the workpiece position detection means 10 with respect to the absolute position is calculated by the correction means 25, and a movement amount correction signal is fed back from there to the command means 22.

FIGS. 2 and 3 are drawings showing a first embodiment of the present invention. Similarly to the case shown in FIG. It has become so.

A side conveyor 8 made of a chain or belt is provided along the conveyor 1 over a predetermined length, and a workpiece position detection head 9 is attached to the side conveyor 8. When the workpiece position detection head 9 captures the workpiece W, the side conveyor 8 is operated and the pulse generator 10 is driven.

Adjacent to the conveyor 1 via the side conveyor 8, two sensors 23a and 23b consisting of a proximity switch or a limit switch as absolute position detection means are installed at a predetermined distance from each other. These sensors 23a
, 23b are activated when the workpiece position detection head 9 passes therethrough. Thereby, the position of the work cart 5, that is, the absolute position of the work W with respect to the conveyor 1 is detected. That is, when the workpiece position detection head 9 passes the sensor 23a, counting of pulse values from the pulse generator 10 is started based on the information, and continues until the workpiece detection head 9 passes the sensor 23b, and the workpiece position detection means 10 detects the pulse value. The distance traveled by the work W and the distances actually measured by both sensors 23a and 23b are calculated by the comparison calculation means 24 shown in FIG. 1 within the control means 11.

On the other hand, the follow-up cart 3 is located at the reference position on the right side in FIG. 2, and the servo motor 12 starts to be activated by the workpiece position detection head 9 or another switch such as a limit switch. Then, the position of the following cart 3 on the rail 2 is calculated from this servo motor 12 by the following cart position detecting means 20, and the position of the following cart 3 on the conveyor 1 is calculated based on the signal from the pulse generator 10 as the workpiece position detecting means. 3 and the position of the workpiece W are compared by the calculation means 21, and if there is a deviation between the two, the follower cart 3 follows by a signal from the command means 22 to the servo motor 12.

A movement amount correction signal is sent to the command means 22 from the comparison calculation means 24 via the correction means 25.

The procedure for correcting the amount of follow-up movement of the follow-up truck 3 will be described with reference to the flowchart shown in FIG. 4.

When the workpiece position detection head 9 passes the sensor 23a,
Start counting the number of pulses from the pulse generator 10. Then, the workpiece position detection head 9 detects the sensor 23b.
When passing through, the moving distance of the workpiece cart 5 is calculated from the number of pulses during this period. This calculated distance value and a preset actual measured distance between both sensors 23a and 23b are compared and calculated. As a result, the correction means 25 determines a calculation constant for the command means 22 in order to indicate the accurate movement distance of the workpiece position detection head 9 with respect to the conveyor 1,
The servo motor 12 is driven based on this calculation constant.

As a result, the tracking trolley 3 can be positioned accurately with respect to the workpiece W.
follows and moves.

The follow-up cart 3 is provided with an industrial robot 4 as a working means, and a robot control means 26 controls the operation of the robot 4 based on a signal from the control means 11. It is possible to assemble parts P such as the following.

FIGS. 5 and 6 are diagrams showing other embodiments of the present invention, and parts common to those in the previous embodiments are given the same reference numerals.

In this embodiment, the pulse generator 10 is directly driven by the chain 7 for conveying the work truck 5 without providing a side conveyor 8 made of a chain or belt. In addition, as an absolute position detector, there are five sensors 2 consisting of phototube switches, etc.
3A to 23E are used. In this case, as in the embodiment described above, the workpiece detection head 9 is connected to the sensor 2.
The moving distance of the workpiece W detected by the pulse generator 10 from passing through the sensor 23B until passing through the sensor 23B may be calculated by the comparison calculating means 24, and the actual distance between the sensors 23A and 23b. ,
In this case, the position of the workpiece W is detected. In other words, each of the sensors 23A to 23E is of a phototube type, and when the sensor 23A detects a characteristic part of the workpiece W, the position of the workpiece W detected by the pulse generator 10 is compared with the actual position of the sensor 23Δ. The correction value is sent to the command means 22 via the correction means 25.
The signal is sent from the servo motor 12 to the servo motor 12. This correction is performed sequentially from sensor 23B until the final sensor 23E is completed. This makes it possible to assemble the parts to the automobile body W with high precision.

(Effects of the Invention) As described above, according to the present invention, the position of the workpiece relative to the conveyor is detected by the workpiece position detection means, and the position of the follower cart relative to the follower means is detected by the follower cart position detection means, The absolute position of the workpiece relative to the conveyor is detected by an absolute position detector, and if there is a difference between the position of the workpiece determined by the absolute position detector and the position of the workpiece determined by the workpiece position detection means, Since a signal is sent to the motor in order to correct this position, it becomes possible to assemble the parts with high precision on the work using a working means such as an industrial robot.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the basic structure of the present invention, FIG. 2 is a plan view showing a follow-up control device according to an embodiment of the present invention,
3 is a block diagram of FIG. 2, FIG. 4 is a flowchart of the follow-up control device shown in FIG. 2.3, and FIG. 5 is a plan view showing the follow-up control device according to another embodiment of the present invention. Fig. 6 is a block diagram of Fig. 4, Fig. 7 is a flowchart of the follow-up device shown in Fig. 5.6, Fig. 8 is a perspective view showing an example of the follow-up control device, and Fig. 9 is an example of the follow-up control device. FIG. 1... Conveyor, 2... Rail (following means), 3...
...Following trolley, 4...Industrial robot working means), 5
... Work truck, 6... Motor, 8... Sub conveyor, 9... Work position detection head, 10... Work position detection means (pulse generator), 11... Control means, 12. ...Servo motor, 20...Following cart position detection means, 21...Calculation means, 22...Command means, 23...Calculation means, 24...Comparison calculation means, 2
5...Correction means. Patent applicant: Nissan Motor Co., Ltd. Figure 1 Cut W Taste q gland Figure 9

Claims (1)

[Claims] Adjacent to a conveyor for transporting a workpiece carriage supporting a workpiece, a following means is provided for conveying a follower carriage along the workpiece carriage, and a working means for performing a predetermined operation on the workpiece is provided on the follower carriage. In the tracking control device,
workpiece position detection means driven by the conveyor to detect the position of the workpiece on the conveyor; and follower cart position detection means to detect the position of the follower cart in the follower means based on a signal from a motor that drives the follower cart. a calculating means for calculating a positional deviation between the workpiece and the following cart based on signals from the workpiece position detecting means and the following cart position detecting means; and a commanding means for sending a signal for correcting the deviation to the motor; an absolute position detector installed adjacent to the conveyor to detect the absolute position of the work with respect to the conveyor; an absolute position signal of the work from the absolute position detector and a position signal of the work from the position detection means; a comparison calculation means for comparing the
and a correction means for sending a movement amount correction signal to the command means based on a signal from the comparison calculation means.