JP2007040920A - Device and method for checking operation limit of actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an operation limit checking device for an actuator suitable for checking the position of movement of an object moved by an actuator, without using a sensor and a lead wire. <P>SOLUTION: Whether or not operations of a plurality of work holding portions 16 are normal is determined by storing beforehand reference position patterns or reference attitude patterns obtained from pictures, taken by a monitor camera 2, of the plurality of holding portions 16 being at return limit positions and moving-out limit positions at a normal time in an instruction mode, and comparing an actual position pattern or actual attitude pattern obtained from pictures, taken by the monitor camera 2, of the return limit positions or moving-out limit positions of the plurality of holding portions 16 in a detection mode, with a reference position pattern or reference attitude pattern stored in the instruction mode. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an actuator operation limit check device and an operation limit check method, and more particularly to an actuator operation limit check device and an operation limit check method suitable for a work positioning device including a plurality of work gripping portions operated by an actuator. is there.

  Conventionally, in order to detect the operating position of an actuator having a piston that reciprocates in a cylinder, a permanent magnet is disposed on the piston, while a reed switch that is activated by the approach of the permanent magnet is disposed on the outer periphery of the cylinder. An apparatus has been proposed (see Patent Document 1).

This is because the detection means for detecting the piston position in response to the magnet mounted on the piston sliding in the cylinder body has a reed switch that responds to the magnet mounted on the piston, a light emitter that emits light, and a lead It has a switching element that switches on the output of the switch and emits light from the light emitter. By reducing the amount of current flowing through the reed switch, even if chattering occurs in the reed switch, welding occurs at the contact part of the reed switch. Thus, it is possible to greatly increase the number of times until the detection is performed, and to provide a detection device having a long lifetime.
Japanese Patent No. 3267558

  By the way, in the detection device having a reed switch for individually detecting the operation position of the actuator and a lead wire for inputting a detection signal to the controller as in the conventional example, the sensor or the lead wire is disconnected (in particular, the actuator If this occurs, the position information of the actuator is not input to the controller, and the equipment is stopped.

  In addition, when the operation of the actuator is transmitted to the object, for example, when the link mechanism is damaged, the operation object is normal even if the actuator operates normally and the operation signal is input to the controller. The operating position will not be reached, and there may be a risk of quality failure of the product to be produced.

  Accordingly, the present invention has been made in view of the above-described problems, and is an actuator operation limit check device and an operation limit suitable for checking the movement position of an operation target operated by an actuator without using a sensor and a lead wire. The purpose is to provide a confirmation method.

  The present invention relates to a monitor camera that captures a plurality of workpiece gripping units that are operated between a return limit position and a limit limit position by an actuator, and determines the positions or postures of the plurality of workpiece gripping units from the video of the monitor camera. The controller stores in advance a reference position pattern or a reference posture pattern obtained from an image obtained by photographing a plurality of workpiece gripping portions at the return limit position and the limit position in the normal state in the teaching mode with a monitor camera. In the detection mode, the actual position pattern or the actual posture pattern obtained from the image obtained by capturing the return limit position or the limit position of the plurality of workpiece gripping portions with the monitor camera and the reference position pattern or the reference posture pattern stored in the teaching mode To determine whether the work gripper is operating normally. It was.

  Therefore, in the present invention, the normal position pattern or the actual posture pattern obtained from the image obtained by capturing the return limit positions or the limit positions of the plurality of workpiece gripping parts with the monitor camera in the detection mode and the normal time previously stored in the teaching mode A reference position pattern or a reference posture pattern obtained from an image obtained by photographing a plurality of workpiece gripping portions at the return limit position and the limit limit position with a monitor camera is compared to determine whether the operation of the workpiece gripping portion is normal or not. Therefore, there is no need to provide a sensor or lead wiring that directly senses the operation limit of the actuator, and there is no equipment failure due to the disconnection. In addition, since the operation of the workpiece gripping part, which is the operation target part, is determined by an image, even if the transmission link existing between the actuator and the actuator is broken, it can be determined whether it is normal or not by the movement. Product quality defects can be prevented in advance.

  Hereinafter, an actuator operation limit check device and an operation limit check method according to the present invention will be described based on each embodiment.

  1 to 9 show a first embodiment of an actuator operation limit check device to which the present invention is applied, and FIGS. 1 to 7 show Example 1 of an actuator operation limit check device. These show Examples 2-3 of the actuator operation limit confirmation device.

  FIG. 1 is a system configuration diagram applied to a workpiece positioning device, FIG. 2 is a schematic diagram of a clamp device in an operating state operated by an actuator, and FIG. 3 is a confirmation of the operation limit of the actuator. FIG. 4 is a flowchart showing a processing procedure executed by the controller, FIG. 5 is a plan view of an actuator return limit state of the positioning device in FIG. 4, and FIG. 6 is a positioning device in FIG. FIG. 7 is a plan view when applied to a workpiece positioning device arranged on a rotary table.

  In FIG. 1, an actuator operation limit confirmation device patterns a workpiece positioning device 1 as a confirmation target, a monitor camera 2 that monitors the operation state of the workpiece positioning device 1, and a video signal input from the monitor camera 2, And a controller 3 that determines whether or not the operation of the workpiece positioning device 1 has been normally performed in comparison with a video pattern stored in advance.

  The workpiece positioning device 1 includes a plurality of positioning gauges 10 and a plurality of clamping devices 11 that clamp the workpieces seated on the positioning gauges 10 by pressing them against the positioning gauges 10 and fixed to a base 12 fixed to a floor or the like. . As shown in FIG. 2, the positioning gauge 10 and the clamp device 11 are arranged at the tip of a gauge post 13 fixed on a base 12, and a gauge portion 15 for positioning a workpiece with a gauge surface 14 at the tip, and the gauge post The clamp position for clamping the workpiece seated on the gauge surface 14 with the workpiece gripping portion 16 facing the gauge surface 14 of the gauge portion 15 with the gauge surface 14 and the workpiece gripping portion 16 are described above. A clamp arm 17 that swings between unclamping positions that are separated from the gauge surface 14, and is also supported by the gauge post 13 so as to be swingable. A piston rod 18 is connected to the clamp arm 17 so that the clamp arm 17 is clamped. And a clamping cylinder 19 (pneumatic cylinder) that swings between the unclamping position and the unclamping position. In addition, the positioning gauge 10 includes a detection unit that slightly protrudes from the gauge surface 14, and a seating sensor 20 that detects when a workpiece is seated on the gauge surface 14 is disposed.

  The workpiece gripping portion 16 of the clamp arm 17 is provided with a conspicuous mark 22 so that it can be distinguished from other portions of the clamp arm 17. Specifically, as shown in FIG. 3, in the workpiece positioning device 1, a plurality of clamping devices 11 are arranged on the base 12, and a mark 22 is marked on the workpiece gripping portion 16 of the clamp arm 17 of each clamping device 11. Has been given. On the base 12, as shown in FIG. 3, reference marks 23 are arranged at the corners. The mark 22 of the workpiece gripper 16 is imaged by the monitor camera 2 together with the reference mark 23 arranged on the base 12 every time it is necessary to confirm the operation limit of the workpiece positioning device 1 that performs a sequence operation. The arrangement pattern of the marks 22 together with the mark 23 is calculated and compared with a reference arrangement pattern stored in advance, and it is determined whether or not each clamp device 11 of the workpiece positioning device 1 has been operated normally.

  As a method of calculating the arrangement pattern of the marks 22 and 23, as shown in FIG. 3, for example, the reference marks 23 and the marks of the workpiece gripping portions 16 in the clamped state of the workpieces 22 and 23 by the workpiece positioning device 1. 22 is captured by the camera 2 to obtain an image. Then, the image is binarized into the mark portions 22 and 23 and the other portions, an array pattern of the mark portions 22 and 23 is created, and the reference of the normal mark portions 22 and 23 created and stored in advance is stored. Compare with sequence pattern. If the arrangement patterns of the two match, each clamping device 11 of the workpiece positioning device 1 determines that the workpiece is normally clamped. If there is a mark 22 that does not match in the comparison, the mark 22 It is determined that the clamping device 11 with 22 is abnormal. In the unclamped state of each clamp device 11, the marks 22 and 23 are similarly imaged by the monitor camera 2, and the image is binarized into the mark portions 22 and 23 and other portions to obtain an array pattern. The success or failure is determined by comparison with a normal unclamped reference sequence pattern stored in advance.

  The operation of the actuator operation limit confirmation apparatus having the above configuration will be described below based on the flowchart shown in FIG. The flowchart shown in FIG. 4 shows the teach mode (left-side flowchart) related to the acquisition of the reference arrangement pattern executed by the controller 3, the acquired reference arrangement pattern, and the arrangement pattern of the marks 22 and 23 in actual operation. And a detection mode (right flowchart) for determining whether or not the operation is abnormal are shown side by side.

  In the teach mode described on the left side, each actuator 19 is operated to the return limit (S1), and the mark 22 of the workpiece gripping portion 16 of the clamp device 11 positioned at the return limit is monitored together with the reference mark 23 on the base 12. The image is taken by the camera 2, the image information is binarized, and the arrangement pattern of each mark 22, 23 is stored in the data file as a return limit reference arrangement pattern (S2). Next, each actuator 19 is operated to the limit (S3), and the mark 22 of the workpiece gripping portion 16 of the clamp device 11 positioned at the limit is imaged by the monitor camera 2 together with the reference mark 23 on the base 12, and the image The information is binarized, and the arrangement pattern of each mark 22, 23 is stored in the data file as the limit reference arrangement pattern (S4), and the process ends. When the input of the reference sequence pattern in the teach mode is completed at the stage where all the necessary reference sequence patterns are stored, the mode is switched to the detection mode and activated every time the clamp device 11 is clamped and unclamped. Whether or not the operation of No. 11 is normal is determined.

  As shown in FIG. 5, for example, the mark 22 of the workpiece gripping portion 16 of each clamping device 11 is aligned with the unclamping position retracted to the outer peripheral side of the workpiece positioning device 1 as shown in FIG. The arrangement is in a state of being aligned alongside the twelve reference marks 23. As described above, when the reference marks 23 are arranged so that the arrangement of the marks 22 and 23 in the standby state is aligned, it is possible to determine whether or not the normal standby state is set before the clamp device 11 is operated. And since it is a simple pattern, it is not necessary to set the installation position of the monitor camera 2 with high precision, and the system configuration can be simplified. Further, as shown in FIG. 6, for example, the obtained limit reference arrangement pattern is such that the mark 22 of the workpiece gripping portion 16 of each clamping device 11 is aligned with the clamp position advanced to the inner peripheral side of the workpiece positioning device 1. Therefore, the reference marks 23 of the base 12 are not arranged, but are arranged in a state where they are aligned in the horizontal direction.

  Here, when the camera position is changed, for example, from above the workpiece positioning device 1 to obliquely upward, if the reference array pattern changes greatly as viewed from the camera side, the reference array pattern is stored again. However, if the basic array pattern does not change and the pattern identity is maintained, it is not necessary to store the reference array pattern again.

  In the detection mode described on the right side, each time the clamp device 11 is clamped or unclamped, it is started, and the mark 22 on the workpiece gripping part 16 after the clamping operation or after the unclamping operation is used as the reference mark 23 on the base 12. At the same time, the image is picked up by the monitor camera 2 and the image information is binarized, and the arrangement pattern of the marks 22 and 23 (which is either the return limit pattern or the limit pattern depending on whether the clamp operation of the clamp device 11 is unclamped or clamped) Is temporarily stored (S5).

  Next, the reference arrangement pattern stored in the teach mode (selecting either the return limit reference arrangement pattern or the output limit reference arrangement pattern depending on whether the clamping operation of the clamp device 11 is unclamping or clamping) is read into the primary storage. (S6).

  Next, the primary storage mark array pattern obtained by imaging is compared with the reference array pattern read into the primary storage (S7). As a result of the comparison, if both patterns match, it is confirmed that the clamping device 11 is normal (S8). If some of the patterns do not match, an alarm display is output, and the workpiece positioning device 1 The sequence operation is stopped (S9).

  FIG. 7 is applied to an assembling apparatus in which the workpiece positioning apparatus 1 is mounted on a turntable 30 that reciprocates and is alternately switched between a component loading / assembling / carrying stage 31 and a component welding stage 32. Show the case. In this way, in an apparatus that produces a workpiece while the workpiece positioning device 1 is moved as a whole, the sensors and lead wires that directly sense the operation limit of the actuator are provided in each clamp device 11. Equipment failure due to disconnection is likely to occur. Accordingly, it is particularly effective to confirm the operation limit by comparing the arrangement pattern of the marks 22 and 23 obtained by imaging the operation of the clamping device 11 with the monitor camera 2 and the reference arrangement pattern.

  As described above, in the actuator operation limit confirmation device applied to the workpiece positioning device 1, the monitor camera 2 images the operation target portions 22 and 23 operated by the actuator 19, the image and the reference stored in advance. Therefore, it is not necessary to provide a sensor or lead wiring that directly senses the operation limit of the actuator 19, and thus to determine whether or not the operation target unit 16 is operating normally. There is no equipment failure due to disconnection. In addition, since the operation of the operation target portion 16 is determined by an image, even when the transmission link existing between the actuator 19 is broken, it can be determined whether the abnormality is normal or not by the movement of the operation target portion. Therefore, it is possible to prevent quality defects of products to be produced.

  Further, by making the operation target portion 16 easily distinguishable from the other by the mark 22, the image captured by the monitor camera 2 can be patterned by binarization and the like, and compared with a reference pattern stored in advance. This also makes it easier and quicker to determine the motion.

  The actuator operation limit confirmation device of the second embodiment shown in FIG. 8 is applied to the robot hand 34 that grips the workpiece of the handling robot 33, and the workpiece gripping portion 36 and the hand of each clamp device 35 of the robot hand 34. Marks 37 and 38 are provided on 34 frames, respectively. As shown in FIG. 3, the marks 38 to be applied to the frame of the robot hand 34 are aligned on a line when, for example, the marks 37 and 38 are located at the unclamping position when the monitor camera 2 takes an image. Is desirable.

  In this case, the posture of the robot hand 34 can be variously changed by the handling robot 33, and the operation limit confirmation posture process is incorporated into the operation sequence of the handling robot 33 following the clamping operation and the unclamping operation. It is possible to make the camera 2 take an easy posture to image the workpiece gripping portion 36. Further, the installation position of the monitor camera 2 can be changed. In this case, it is only necessary to change the operation limit confirmation posture, and the installation position of the monitor camera 2 can be arbitrarily set.

  In the workpiece gripping part 36 of the robot hand 34, the return limit reference array pattern based on the captured image at the time of unclamping and the output limit reference array pattern at the time of clamping are stored in advance, as in the first embodiment. Whether or not the clamping operation and the unclamping operation are normally performed can be determined by the imaging by the monitor camera 2.

  In addition, since the work gripping portion 36 is imaged by the monitor camera 2, the sensor and the lead wire for the actuator installed in the robot hand 34 whose posture can be freely changed by the handling robot 33 can be eliminated, and the equipment is stopped due to the disconnection of the wiring. Disappears. Further, since the operation restriction due to the wiring of the lead wire is reduced, the operation range of the robot hand 34 can be expanded.

  The actuator operation limit confirmation device of the third embodiment shown in FIG. 9 is applied to the operation limit confirmation of the clamp device 41 of the locate clamp device 40. The locating clamp device 40 is configured such that a positioning locating pin 42 is inserted into a locating hole of a panel material, and a mark that can be distinguished from the other is provided on a clamping claw 43 protruding from the locating pin 42. In this case, the clamp claw 43 constitutes a workpiece gripping portion that grips a panel-shaped workpiece with the stepped portion 44 (gauge reference) of the base of the locate pin 42. The clamp pawl 43 has an extension limit position protruding from the locate pin 42 and a return limit position retracted into the locate pin 42, and is switched to either of the two positions by an actuator.

  In this case, the operation limit of the clamp claw 43, which is a workpiece gripping portion, is confirmed by checking whether the mark provided on the clamp claw 43 protrudes from the locating pin 42 or retreats into the locating pin 42 on the photographing screen by the monitor camera 2. Whether or not the operation is normal is determined based on whether or not the operation can be performed. However, the return limit reference arrangement pattern and the return limit arrangement pattern obtained by imaging every operation are patterns in which only reference marks (not shown) are arranged. Even in this case, the return limit reference array pattern and the output limit reference array pattern are stored in the controller 3 and obtained from the imaging screen by the monitor camera 2 in relation to the return limit and the operation of the clamp pawl 43 by the actuator. By comparing the mark arrangement pattern with each of the reference arrangement patterns, it is possible to determine whether the clamping operation and the unclamping operation are normally performed.

  In the above-described embodiment, the image of the mark 22 provided on the work gripping portion 16 of the clamp device 11 is captured as an object to be imaged by the monitor camera 2, and whether the operation at the return limit or the limit is normal according to the arrangement pattern of the mark 22 Although not shown in the figure, a mark that can be distinguished from others is placed on the entire workpiece gripping portion 16 of the clamping device 11, and the reference posture pattern or limit at the return limit at the time of teaching is not shown. By comparing the reference posture pattern at the actual posture pattern at the return limit at the time of detection or the actual posture pattern at the limit, it is determined whether or not the operation of the workpiece gripper 16 is normal. There may be.

  In the present embodiment, the following effects can be achieved.

  (A) In the teaching mode, a reference position pattern or a reference posture pattern obtained from an image obtained by photographing the plurality of workpiece grippers 16 at the return limit position and the limit position at the normal time with the monitor camera 2 is stored in advance, and the detection mode is set. At this time, the actual position pattern or actual posture pattern obtained from an image obtained by capturing the return limit positions or the limit positions of the plurality of workpiece gripping portions 16 with the monitor camera 2 and the reference position pattern or reference posture pattern stored in the teaching mode are obtained. In comparison, since it is determined whether or not the operation of the workpiece gripping portion 16 is normal, there is no need to provide a sensor or lead wiring that directly senses the operation limit of the actuator 19, and there is no equipment failure caused by the disconnection. In addition, since the operation of the operation target unit 16 is determined by an image, it is determined whether the abnormality is normal or not by the movement of the operation target unit 16 even when the transmission link existing between the actuator 19 is broken. It is possible to prevent quality defects of products to be produced.

  (A) The reference position pattern and the actual position pattern are a reference placed at a portion that does not move due to the operation of the actuator 22 and the mark 22 provided at the portion of the workpiece gripping portion 16 having the largest operating stroke between the return limit and the extension limit. By using an array pattern composed of the marks 23, the image captured by the monitor camera 2 can be binarized, etc., and can be easily compared with a pre-stored reference pattern, so that the operation is determined. Can be made easier and faster.

  (C) When the reference mark 23 is arranged at a position aligned with the mark 22 installed on the plurality of workpiece gripping portions 16 operated to the return limit, before the clamp device 11 is operated, the normal standby state is set. Since it is a simple pattern, it is not necessary to set the installation position of the monitor camera 2 with high accuracy, and the system configuration can be simplified.

  (D) By setting the workpiece gripping portion 16 as a portion that contacts the workpiece of each clamp arm 17 of the workpiece positioning device 1 including the plurality of clamping devices 11, all the clamping devices 11 can be operated normally by imaging with the monitor camera 2. Abnormalities can be determined at the same time.

  (E) Only the posture of the detection mode is added to the handling robot 33 by setting the workpiece gripping portion as a part that contacts the workpiece of each clamp arm 36 of the robot hand 34 of the handling robot 33 including the plurality of clamp devices 35. It is possible to check the operation limit.

  (F) By using the clamp claw 43 protruding and retracting from the locate pin 42 of the locate clamp device 40 as the workpiece gripping portion, it is possible to easily determine whether or not the operation of the locate clamp device 40 is normal.

The system block diagram of Example 1 which applied the actuator operation limit confirmation apparatus of one Embodiment of this invention to the workpiece positioning apparatus. The schematic of the clamp apparatus of the operation state similarly operated with an actuator. The top view of the workpiece | work positioning device to which the operation limit confirmation apparatus of an actuator is applied. The flowchart which shows the process sequence performed by a controller. The top view of the actuator return limit state of the positioning device of FIG. FIG. 5 is a plan view of an actuator extended state of the positioning device of FIG. 4. The top view at the time of applying to the workpiece positioning device arrange | positioned on a rotary table. The side view of Example 2 which applied the operation limit confirmation apparatus of the actuator to the robot hand. The side view of Example 3 which applied the operation limit confirmation apparatus of the actuator to the locate clamp apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Work positioning device 2 Monitor camera 3 Controller 10 Gauge 11 Clamping device 12 Base 13 Gauge post 14 Gauge surface 16, 36 Work gripping part, operation target part 17 Clamp arm 19 Actuator 22, 37, 43 Mark 23, 38 Reference mark

Claims (7)

A monitor camera for photographing a plurality of workpiece grippers that are operated between a return limit position and a limit position by an actuator;
A controller for determining the positions or postures of a plurality of workpiece gripping units from the image of the monitor camera,
The controller stores in advance a reference position pattern or a reference posture pattern obtained from an image obtained by photographing a plurality of workpiece gripping portions at a return limit position and an extension limit position in a normal state in the teaching mode with a monitor camera. Comparing the actual position pattern or actual posture pattern obtained from the image captured by the monitor camera with the return limit position or the limit position of the plurality of workpiece gripping units and the reference position pattern or reference posture pattern stored in the teaching mode, An apparatus for confirming an operation limit of an actuator, characterized by determining whether or not the operation of a workpiece gripping portion is normal.   The reference position pattern and the actual position pattern are composed of a mark provided at a part of the work holding portion having the largest operating stroke between the return limit and the limit and a reference mark arranged at a part that does not move depending on the operation of the actuator. The actuator operation limit confirmation device according to claim 1, wherein the operation limit confirmation device is an arrangement pattern.   3. The actuator operation limit confirmation device according to claim 2, wherein the reference mark is arranged at a position aligned with a mark installed on a plurality of workpiece gripping portions operated to a return limit.   The operation limit of the actuator according to any one of claims 1 to 3, wherein the workpiece gripping portion is a portion that contacts a workpiece of each clamp arm of a workpiece positioning device including a plurality of clamping devices. Confirmation device.   4. The actuator according to claim 1, wherein the workpiece gripping portion is a portion that contacts a workpiece of each clamp arm of a robot hand of a handling robot including a plurality of clamp devices. Operation limit confirmation device.   4. The operation limit confirmation device for an actuator according to claim 1, wherein the workpiece gripping portion is a clamp claw that protrudes and protrudes from a locate pin of a locate clamp device. 5. A teaching mode for obtaining a reference position pattern or a reference posture pattern obtained from an image obtained by photographing a plurality of workpiece gripping portions at a return limit position and a limit position at a normal time by a monitor camera;
Compare the actual position pattern or actual posture pattern obtained from the image captured by the monitor camera with the return limit position or the limit position of the plurality of workpiece gripping parts with the reference position pattern or reference posture pattern obtained by the teaching mode, and And a detection mode for determining whether or not the operation of the gripping part is normal.

Images