JP2008036714A - Control method of workpiece carrying device and control device thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a control method of a workpiece carrying device, which employs an optical communication system having resistance to noise, has high reliability for the position displacement of a carriage, and is inexpensively constituted. <P>SOLUTION: The control device is composed of: proximity switches 37, 38, 39 and a position detecting plate 40 which detect the carriage 7 in the specified position of a guide rail 6; a controller 31 provided on a fixed side; an encoder for detecting a current position of the carriage 7; and a communication means for giving and receiving the data by the optical communication between the encoder and the controller 31. The controller 31 has a storage device for storing the position data for the specified position of the carriage 7, compares the position data stored in the storage device with the current position data of the carriage 7 transmitted from the encoder through the communication means, and determines whether the difference is within an allowance. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a control method and a control device for a workpiece conveying device in which a workpiece gripping means is mounted on a traveling body that runs along a guide rail, the workpiece is gripped by the workpiece gripping means and transported to a predetermined position. is there.

  As a device for loading / unloading workpieces to / from a processing machine or the like, a guide rail for moving the traveling body is arranged above the processing machine, and a workpiece gripping device (robot hand) is attached to the traveling body traveling along the guide rail. An on-board work transfer device is used.

  By the way, conventionally, in this type of work transfer apparatus, it has been necessary to connect a communication line for transmitting and receiving various control data to the traveling body from the fixed side in addition to the power source for driving. There were complicated line installation work, costs required for communication lines, and maintenance problems. Therefore, in order to solve these problems, superimposition communication is performed by using a wireless communication line to control the traveling body (see Patent Document 1) or using a trolley feed line. (See Patent Document 2) has been proposed.

  That is, in the one described in Patent Document 1, in order to eliminate the risk of malfunction due to noise mixing during communication, a program step is provided for executing a controller on both the stationary side and the traveling body side (moving side). At the start time, the current position data on the moving side is compared with the command data on the fixed side, and the program operation is executed only when the two data match.

  Moreover, in the thing of patent document 2, in order to be able to respond | correspond easily to the stroke change of the driving | running | working part accompanying the change of a process line, or the addition request | requirement of a loading device, both the fixed side and the traveling body side (moving side) And a trolley system for supplying power to the moving side, and a communication system between the moving side controller and the fixed side controller is a superimposed communication system that superimposes a signal on the power supply current.

JP 2003-340758 A JP-A-2005-118916

  However, in the thing of the said patent document 1, when the radio | wireless communication line by an electromagnetic wave is used, there exists a problem that possibility of noise mixing is high. In addition, in both of the devices described in Patent Documents 1 and 2, since it is necessary to provide a controller on both the fixed side and the traveling body side, there is a problem that the system configuration becomes large and the cost increase cannot be avoided. .

  The present invention has been made in view of such problems, and employs an optical communication system that is resistant to noise, and can detect the displacement of a traveling body with a highly reliable and inexpensive configuration. It is an object of the present invention to provide a control method and a control device for a work transfer device.

In order to achieve the above object, a method for controlling a workpiece transfer apparatus according to the first invention comprises:
A method for controlling a workpiece transfer device that mounts a workpiece gripping means on a traveling body that runs along a guide rail, grips the workpiece by the workpiece gripping means, and transfers the workpiece to a predetermined position.
When the traveling body is at a specific position, the current position data of the traveling body is transmitted to a controller provided on the fixed side by optical communication, and the transmitted current position data and the specific position of the traveling body are Comparing with storage position data stored in advance, and when the deviation between the current position data and the storage position data is within an allowable range, the control operation of the traveling body is executed. .

Further, the control device for the workpiece transfer device according to the second invention is:
A control device for a workpiece transfer device that mounts a workpiece gripping means on a traveling body that runs along a guide rail, grips the workpiece by the workpiece gripping means, and transfers the workpiece to a predetermined position,
Traveling body detection means for detecting the traveling body at a specific position of the guide rail, a controller provided on the fixed side, current position detection means for detecting the current position of the traveling body, the current position detection means, and the controller And communication means to exchange data with the optical communication,
The controller is transmitted from the current position detection means via the storage means for storing position data for the specific position of the traveling body, the storage position data stored in the storage means, and the communication means. The present invention is characterized in that there is provided a determination means for comparing with the current position data of the traveling body and determining whether or not the deviation is within an allowable range.

  In the second aspect of the present invention, it is preferable that an abnormality processing unit for performing an abnormal process when the determination unit determines that the deviation exceeds the allowable range is provided (third aspect).

  In the second or third aspect of the invention, the traveling body detection means includes a position detection plate provided on the traveling body, and a proximity switch provided on the guide rail side for detecting the position detection plate. It is preferable to be carried out (fourth invention).

  According to the first invention or the second invention, since the current position data of the traveling body is transmitted to the fixed side by optical communication, it is more resistant to noise than the method using the radio communication line using radio waves. It is extremely strong and can eliminate the risk of malfunction caused by noise. In addition, it is not necessary to provide a controller on both the fixed side and the traveling body side, and a simple structure in which a controller is provided only on the fixed side, the presence or absence of normality of the current position data at a specific position on the traveling body It can be determined with certainty.

  Next, a specific embodiment of a control method and a control device for a workpiece transfer device according to the present invention will be described with reference to the drawings.

  FIG. 1 shows a front view of a workpiece transfer device according to an embodiment of the present invention, and FIG. 2 shows a side view of the workpiece transfer device. 3 is an enlarged view of a portion P in FIG. 2, FIG. 4 is a plan view of the carriage, FIG. 5 is a front view of the carriage, and FIG. 6 is a side view of the carriage. Each is shown.

  As shown in FIGS. 1 and 2, the workpiece transfer device 1 according to the present embodiment includes a plurality of columns 2, 2, a horizontal girder 3 fixed to the upper end surface of these columns 2, 2, a column 2, and a horizontal column. A traveling platform 4 comprising a guide rail 6 fixed to the beam 3, a carriage (running body) 7 traveling along a guide rail 6 and above a processing machine (crankshaft mirror in this embodiment) 5 It is configured with.

  As shown in FIGS. 1 and 4 to 6, the carriage 7 is driven by a traveling servomotor 9 mounted on a rectangular carriage body 8 in a front view. The pinion 12 mounted on the shaft is engaged with the rack 14 attached to the base frame 6 a of the guide rail 6 via the reference block 13 so that the pinion 12 can travel along the guide rail 6. As shown in FIG. 3, an upper rail 15 is attached to the upper surface of the reference block 13, a lower rail 16 is attached to the lower surface of the base frame 6a, and a load receiving roller 17 attached to the carriage body 8 is provided. The carriage 7 is slidably contacted with the upper surface of the upper rail 15 to receive and support the load of the carriage 7, and the upper rail 15 and the lower rail 16 are sandwiched from both sides by the guide rollers 18 to guide the traveling of the carriage 7.

  On the carriage body 8, an elongated rectangular tubular lifting body 10 is installed so as to be slidable in the vertical direction, and a work gripping device (work gripping means) 20 is attached to the lower end of the lifting body 10. . Here, the lifting body 10 is a rack in which a pinion 19 attached to the drive shaft of the lifting servomotor 11 is attached to the lifting body 10 by driving of the lifting servomotor 11 mounted on the carriage body 8. By being engaged with the gear 21, it is moved up and down between the upper conveyance position (solid line position in FIG. 1) and the lower workpiece supply / removal position (chain line position). Although the detailed structure of the workpiece gripping device 20 is omitted, as shown in FIG. 2, the same structure as the first finger unit 22A having a pair of front and rear fingers for gripping the workpiece. The second finger unit 22B and the second finger unit 22B are arranged to form a predetermined angle (about 135 °), the workpiece that has been processed by one finger unit 22B is carried out, and then processed by the other finger unit 22A. It is a so-called double-hand workpiece gripping device that carries in workpieces.

  As shown in FIGS. 3 and 6, the guide rail 6 includes a base frame 6 a having a hollow rectangular cross section, and a trolley mounting bracket 23 is attached to the base frame 6 a, and the trolley mounting bracket 23 is attached to the trolley mounting bracket 23. A power supply trolley 24 as a power supply unit equipped with a plurality of trolley wires 24a is supported. A support bracket 26 is attached to the lower surface of a support frame 25 provided so as to project rearward with respect to the carriage body 8. Power and signals are supplied to the support bracket 26 from a trolley wire 24 a of the power supply trolley 24. A current collecting unit 27 is supported. In FIG. 3, what is indicated by reference numeral 28 is a current collecting trolley terminal box.

  Optical communication transmitting / receiving sections (communication means) 29 and 30 are provided at the lower portion of the support frame 25 and at the end of the gantry 4 facing the support frame 25, respectively. These optical communication transmission / reception units 29 and 30 perform transmission / reception of control commands to / from the carriage 7 and the work gripping device 20 attached thereto by an optical communication transmission / reception conversion element.

  As shown in FIG. 7 (schematic diagram showing the system configuration of the work transfer device), the support 2 on one side is provided with a ground control panel (hereinafter referred to as “controller”) 31, and the controller 31 and the gantry 4. The upper optical transmission / reception unit 30 is connected by a communication cable 32, and the controller 31 and the remote input / output device 33 of the processing machine 5 are connected by a communication cable 34.

  In addition, power and signals from the AC power supply are supplied to the trolley wire 24a from the trolley terminal box 34A arranged on the upper portion of the column 2, and from the trolley wire 24a to the guide rail 6 via the current collecting unit 27. Supplied to the traveling carriage 7. An upper control panel 35 having a servo amplifier 35 a is mounted on the carriage 7. The upper control panel 35 is supplied with power from the trolley wire 24 a and with a control signal from the optical communication transceiver unit 29. The Further, a bending holding member (cable bear (registered trademark)) 36 is disposed between the lifting body 10 provided on the carriage 7 and the upper control panel 35, and a power line disposed in the cable bear 36. Thus, power is supplied to the workpiece gripping device 20 and a control signal is exchanged between the upper control panel 35 and the workpiece gripping device 20 by a signal line arranged in the cable bear 36. ing.

  In such a system, an operation command from the controller 31 installed on the fixed side is given to the upper control panel 35 by optical communication via the communication cable 32 and the optical communication transmitting / receiving units 30 and 29. Based on the servo amplifier 35a, the servo motor 9 for traveling, the servo motor 11 for lifting and lowering, the swing motor for swinging the finger units 22A and 22B of the workpiece gripping device 20, and the clamp motor for opening and closing the fingers (both not shown). Is activated.

  Next, traveling control of the carriage 7 by the traveling servomotor 9 will be described. A storage device (storage means) comprising a ROM is connected to the controller 31, and position data at a predetermined position of the carriage 7 is stored in the storage device. Based on the operation command, the controller 31 sends a speed command (voltage command for commanding rotation of the travel servomotor 9) and a servo ON command (command for enabling control of the travel servomotor 9) to the servo amplifier 35a by optical communication. Output to. Based on this, the servo amplifier 35a converts the power supplied from the power supply power source such as AC 200V into a drive power signal corresponding to the speed command and outputs it to the traveling servo motor 9. The servo amplifier 35a feeds back a pulse signal from an encoder (current position detecting means) built in the traveling servo motor 9 to the upper control panel 35, and the motor rotation speed calculated from the pulse signal; The traveling servo motor 9 is controlled so that the deviation from the speed command becomes small. In this way, a feedback loop is formed, and the traveling servomotor 9 is rotationally controlled so as to coincide with the target position or target speed input to the controller 31.

  As described above, in this embodiment, optical communication that is resistant to radio wave noise is adopted as a communication method between the carriage 7 on the moving side and the fixed side, so that noise during communication is higher than that of a conventional radio communication method using radio waves. The risk of malfunction due to contamination can be eliminated. However, in order to reliably eliminate a malfunction due to an encoder failure or the like, the following misalignment detection system for the carriage 7 is employed in the present embodiment.

  As shown in FIG. 8 (a), the guide rail 6 has a position corresponding to the workpiece loading position (above the left column 2 in the figure) and a position corresponding to the workpiece machining position (above the processing machine 5). The proximity switches (capacitance type detection switches) 37, 38, and 39 are installed at positions corresponding to the workpiece unloading positions (above the right column 2 in the drawing). On the other hand, on the carriage 7, a position detection plate (position detection dog) is provided so as to face the proximity switches 37, 38, 39 when the carriage 7 reaches the workpiece carry-in position, the workpiece machining position, and the workpiece carry-out position. 40 is attached. Thus, when the carriage 7 reaches any one of the workpiece carry-in position, the workpiece machining position, and the workpiece carry-out position (these positions are referred to as “positional deviation check points”), the proximity switches 37, 38, 39 are moved to the position detection plate. 40 is detected, and the detection signal is transmitted to the controller 31.

  Next, processing in the positional deviation detection system for the carriage 7 will be described with reference to the flowchart shown in FIG.

S1: Proximity switches 37, 38, and 39 detect the position detection plate 40 to determine whether or not the carriage 7 has reached a misalignment check point (any one of the workpiece loading position, workpiece machining position, and workpiece unloading position). Judgment by whether or not.
S2: When the carriage 7 has reached the misalignment check point, a detection signal is transmitted from the proximity switches 37, 38, 39 to the controller 31. Based on this transmission signal, the controller 31 reads position data of the carriage 7 corresponding to the position of the check point from the storage device.
S3: Next, the read position data (storage position data) is compared with the current position data of the carriage 7 transmitted from the encoder, and a deviation between the two is obtained by calculation.
S4: It is determined whether or not the obtained deviation is within a preset allowable value. If it is within the allowable value, it is determined to be normal and the operation is continued. On the other hand, if the allowable value is exceeded, the process proceeds to step 5.
S5: Since it is a case where the deviation exceeds the allowable value, it is determined that there is an abnormality, and abnormality processing such as interrupting operation and issuing an alarm is performed.

  In the present embodiment, if the carriage 7 is not at the misalignment check point when the work transfer device 1 is started, the carriage 7 is first moved at a low speed toward the position of the misalignment check point, and then the misalignment check is performed. The stored position data stored in the controller 31 at the point is compared with the current position data, and if both position data match, the operation is switched to the normal operation (high-speed processing).

  As described above, according to the misregistration detection system of the present embodiment, it is possible to determine the presence or absence of misregistration by comparing the stored position data with the current position data at the misregistration check point that is the specific position. Therefore, it is not necessary to provide a controller on both the fixed side and the carriage side as in the prior art, the controller 31 is provided only on the fixed side, and the upper control panel 35 on the carriage 7 has no controller mounted thereon. The position shift can be detected with high accuracy. For this reason, the system configuration can be simplified. Further, in the present embodiment, since a method in which the current position data of the carriage 7 is transmitted to the fixed side by optical communication is adopted, it is much stronger against noise than a method using a radio communication line using radio waves, There is an advantage that the risk of malfunction due to noise mixing can be eliminated in advance.

  In the present embodiment, the description has been given of the three positions of the workpiece loading position, the workpiece machining position, and the workpiece unloading position as the position shift check points. However, at least one position shift check point is provided to achieve a desired purpose. be able to. In addition to the above position, this misalignment check point can also be provided, for example, at a greasing position (lubricating oil supply position) that is a position retracted from the workpiece loading position toward the end of the guide rail.

  In the present embodiment, the proximity switches 37, 38, and 39 have been described using capacitive detection switches, but other proximity detection switches may be used as the proximity switches.

The front view of the workpiece conveyance apparatus which concerns on one Embodiment of this invention. The side view of the workpiece conveyance apparatus which concerns on one Embodiment of this invention Part P enlarged view of FIG. Top view of carriage Front view of carriage Side view of carriage Schematic diagram showing the system configuration of the workpiece transfer device Carriage displacement detection system explanatory diagram Flowchart showing processing contents of carriage displacement detection system

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Work conveying apparatus 4 Base 5 Processing machine 6 Guide rail 7 Carriage (running body)
9 Servo motor for traveling 10 Lifting body 20 Work gripping device (work gripping means)
29, 30 Optical communication transceiver (communication means)
31 controller (determination means, abnormality processing means)
35 Upper control panel 35a Servo amplifiers 37, 38, 39 Proximity switch (traveling body detection means)
40 Position detection plate (traveling body detection means)

Claims (4)

A method of controlling a workpiece transfer device that mounts a workpiece gripping means on a traveling body that runs along a guide rail, grips the workpiece by the workpiece gripping means, and transfers the workpiece to a predetermined position,
When the traveling body is at a specific position, the current position data of the traveling body is transmitted to a controller provided on the fixed side by optical communication, and the transmitted current position data and the specific position of the traveling body are Comparing storage position data stored in advance, and executing a control operation of the traveling body when a deviation between the current position data and the storage position data is within an allowable range. Control method. A control device for a workpiece transfer device that mounts a workpiece gripping means on a traveling body that runs along a guide rail, grips the workpiece by the workpiece gripping means, and transfers the workpiece to a predetermined position,
Traveling body detection means for detecting the traveling body at a specific position of the guide rail, a controller provided on the fixed side, current position detection means for detecting the current position of the traveling body, the current position detection means, and the controller And communication means to exchange data with the optical communication,
The controller is transmitted from the current position detection means via the storage means for storing position data for the specific position of the traveling body, the storage position data stored in the storage means, and the communication means. A control device for a workpiece transfer device, comprising: a determination unit that compares the current position data of the traveling body and determines whether or not the deviation is within an allowable range.   The control apparatus for a workpiece transfer apparatus according to claim 2, further comprising an abnormality processing unit that performs an abnormality process when the determination unit determines that the deviation exceeds the allowable range.   4. The workpiece conveyance according to claim 2, wherein the traveling body detection unit includes a position detection plate provided on the traveling body and a proximity switch provided on the guide rail side and detecting the position detection plate. Control device for the device.

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