JP2019051558A - Positional deviation inspection device and positional deviation inspection method - Google Patents

Abstract

To provide an automatic inspection device which can inspect relative positional relationship of components by an inspection gauge in a prescribed time without resorting to the sense of an operator.SOLUTION: There is provided a positional deviation inspection device according to which an inspection gause is inserted in an inspection hole of inspection object components which are overlapped on one another, whereby whether or not mutual relative positions fall within a reference range is determined. In this positional deviation inspection device, the followings are provided: a manipulator; a vision sensor 5 which is mounted on the manipulator so as to be capable of recognizing a position of the inspection hole; an end effector which is provided at a tip of the manipulator via a force sensor 7, and onto which a pin gauge 8 and block gauges 9, 10, which are used for inspection of positional deviation, are so mounted as to be selectively usable; and attitude correction means which, when detecting a reaction force by the force sensor 7, calculates an attitude change for continuing an insertion operation between the pin gauge 8 and the block gauges 9, 10, and the inspection object component from a direction and a magnitude of said reaction force, and changes an attitude by a minute amount.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a positional deviation inspection device and a positional deviation inspection method for inspecting the relative positional relationship between components using an inspection gauge.

  For products that require inspection of the relative positional relationship between parts after assembly is completed, an inspection by an inspector may be performed using an inspection gauge. Especially for products that require accuracy in operation, such as industrial robots, the accuracy of the initial position of each arm is required, so inspection arms and inspection grooves are provided in each adjacent arm. An employee uses an inspection gauge to determine whether or not the product is acceptable.

However, in recent years, automation and labor saving using robots are rapidly progressing at production sites, and automation using robots in such inspection processes has become a major issue.
The difficulty in automating this inspection process is how to smoothly insert the inspection gauge into the inspection hole having a precise fitting relationship using a robot. Several patent techniques that automate the part insertion work that has been relied on the human sense so far with a technique using a force sensor have been disclosed (for example, see Patent Document 1).

  In the robot control device disclosed in Patent Document 1, a reaction force generated at the time of insertion is detected by gripping a component via a force sensor 12 as shown in FIG. By precisely adjusting the position of the parts, galling occurs between the assembly hole and the parts during assembly (excessive torque is generated when the insertion member is inserted, and a large portion is brought into contact with the inserted member. There is disclosed a means for avoiding a phenomenon in which frictional force is generated and insertion is difficult (also referred to as “biting phenomenon”).

Japanese Patent No. 3352173

  According to the technique disclosed in Patent Document 1, it is possible to automatically insert a component into the assembly hole while avoiding galling without relying on an operator. However, the fitting between the assembly hole and the part is not a precise fitting as required when inserting the inspection gauge, and cannot be applied as a technique for securely inserting the inspection gauge into the inspection hole.

  The present invention has been made in view of such a background, and is capable of automatically inspecting the relative positional relationship between components by a test gauge within a predetermined time while avoiding galling without relying on the operator's sense. An object is to provide an inspection apparatus and an inspection method.

  In order to solve the above-described problem, the invention according to claim 1 is configured such that the pin gauge is inserted into the inspection hole formed in the first inspection target component and the second inspection target component that overlap each other, or the block gauge is The relative positions of the first inspection target component and the second inspection target component are within the reference range by being inserted into the inspection grooves formed in the first inspection target component and the second inspection pair component adjacent to each other. A misalignment inspection apparatus for determining whether or not a manipulator installed adjacent to a line on which a product including the first inspection target component and the second inspection target component is manufactured, and the inspection hole or the A vision sensor mounted on the manipulator and the manipulator via a force sensor so that an accurate position can be recognized by photographing the inspection groove from a close position. -When the reaction force is detected by an end effector that is provided at the tip and that can be selectively used for the pin gauge and block gauge used for the displacement inspection and the force sensor, the direction and magnitude of the reaction force And a posture correction means for calculating a change in posture for continuing the insertion operation of the pin gauge and block gauge and the inspection target component, and changing the posture by a minute amount.

  According to this configuration, in the conventional work in which the inspection gauge is inserted into the inspection hole or the inspection groove and the relative position of the parts is determined based on the sense of the hand of the operator, The robot can perform the same work as the worker without relying on the sense of hands. In addition, since the end effector is mounted so that the pin gauge and the block gauge can be selectively used, it is possible to correspond to the inspection hole or the inspection groove without changing the gauge. That is, the inspection can be automatically performed without human intervention.

  The invention according to claim 2 is the inspection apparatus according to claim 1, wherein the tip portion of the pin gauge is chamfered with a surface having an angle of 15 to 45 degrees with respect to the outer peripheral surface, and the guiding shape is It is formed.

  According to this configuration, the gauge insertion operation can be smoothed and shortened. Normally, the fitting between the inspection gauge and the inspection hole is precisely configured, so if the insertion operation is performed without chamfering, the position of the previous inspection hole or inspection groove is recognized by the vision sensor. Even if correction is performed, interference between the two cannot be avoided, and a complicated operation is required for the initial operation of insertion. By adding the chamfering, it is possible to smoothly perform the initial insertion operation without performing a complicated search operation due to the enticing effect.

  The invention according to claim 3 is the inspection apparatus according to claim 1, wherein the tip portion of the block gauge is chamfered at a surface having an angle of 30 to 45 degrees with respect to the side surface, and A tip portion inserted into the inspection target component and a tip portion inserted into the second inspection target component are configured to be separated from each other.

  According to this configuration, the gauge insertion operation can be smoothed and shortened in the same manner as described in claim 2. Normally, the fitting between the inspection gauge and the inspection groove is precisely configured, so if there is no chamfering and the insertion operation is performed with an inspection gauge with a continuous tip, interference between the two cannot be avoided and the insertion is performed. The initial operation requires complicated search operations. The leading effect by adding the chamfer, and the initial insertion smoothly by being configured so that the tip portion inserted into the first inspection target component and the tip portion inserted into the second inspection target component are separated from each other The operation can be performed.

  According to a fourth aspect of the present invention, the pin gauge is inserted into the inspection holes formed in the first inspection target component and the second inspection target component that overlap each other, thereby the first inspection target component and the second inspection target. A positional deviation inspection method for determining whether or not a relative position between components is within a reference range, wherein a robot is operated to bring a vision sensor closer to the first inspection target component or the second inspection target component, A position correction step of recognizing the exact position of the inspection hole, calculating an error from the position taught in advance, and correcting the operation instruction of the robot corresponding to the error, and the corrected operation An insertion step of operating the robot according to an instruction, moving the tip of the pin gauge on the central axis of the inspection hole, and inserting the pin gauge from the central axis; and the pin gauge When the inspection hole comes into contact during insertion, the direction and magnitude of the reaction force is detected by the force sensor, the amount of change in the posture of the pin gauge required to reduce the reaction force is calculated, and the pin gauge And a posture correcting step of changing the posture of the lens by a minute amount.

  According to this method, in the conventional work in which the inspection gauge is inserted into the inspection hole and the relative position of the parts is judged to be good or bad depending on the feeling of the operator's hand, It is possible to cause the robot to perform a precise insertion work equivalent to that of the operator by the operation of the robot without depending on it.

  According to a fifth aspect of the present invention, by inserting a block gauge into an inspection groove formed in a first inspection target component and a second inspection target component adjacent to each other, the first inspection target component and the second inspection target A positional deviation inspection method for determining whether or not a relative position between components is within a reference range, wherein the robot is operated to bring a vision sensor closer to a first inspection target component or a second inspection target component, and the inspection A position correcting step of recognizing the exact position of the groove, calculating an error from the position taught in advance, and correcting the subsequent robot operation instruction in accordance with the error, and in accordance with the corrected operation instruction After the robot is operated and the block gauge is moved so as to face the inspection groove, one end of the block gauge is inserted into the inspection groove of the first inspection target component. And a second insertion step of inserting the other tip portion of the block gauge tip into the inspection groove of the second inspection target component. .

  According to this method, in the conventional work in which the inspection gauge is inserted into the inspection groove and the relative position of the parts is judged to be good or bad depending on the feeling of the operator's hand, It is possible to cause the robot to perform a precise insertion work equivalent to that of the operator by the operation of the robot without depending on it.

  According to the present invention, in the conventional work in which the inspection gauge is inserted into the inspection hole or the inspection groove and the relative position of the components is judged as good or bad depending on the sense of the hand of the operator, It is possible to provide an automatic inspection apparatus capable of inspecting the relative positional relationship between parts by an inspection gauge within a predetermined time while avoiding galling without relying on a sense.

It is the whole figure which shows the test | inspection site | part of the robot which is a test object, and a partial enlarged view. 1 is an overall view of a misalignment inspection apparatus according to the present invention. It is an enlarged view of the test | inspection unit of the position shift inspection apparatus which concerns on this invention. It is the schematic which showed the process which inserts the pin gauge which concerns on this invention in the hole for an inspection. It is the schematic which showed the process which inserts the block gauge which concerns on this invention in the groove | channel for inspection. It is the schematic which showed the chamfering shape of the pin gauge and block gauge which concern on this invention. It is the schematic which showed the relationship between the insertion process and result which concerns on this invention, and test | inspection determination. It is the table | surface which showed the relationship of three parameters, insertion time, insertion amount, reaction force, and test | inspection determination. The control block diagram of the position shift inspection apparatus which concerns on this invention is shown. It is an example of the prior art using the force sensor which inserts components in a hole by a robot.

<Configuration of misalignment inspection device>
A positional deviation inspection apparatus according to an embodiment of the present invention will be described below in detail with reference to the drawings.
FIG. 1A shows an inspected robot 50 to be inspected. Since the robot 50 is required to perform an accurate operation, it is necessary to check whether the relative positional relationship between the arms in the initial state is within a certain standard, and a precise inspection using an inspection gauge is performed as the means. May be. At this time, the examination is performed on all joint portions having a degree of freedom. In the elbow joint portion, as shown in FIG. 1B, a through hole (inspection hole) is formed in the portion where the adjacent first arm (first inspection target component) 100 and second arm (second inspection target component) 200 overlap. ) 53 is perforated, and it is confirmed that the relative angle formed by both arms 100 and 200 is within a certain angle range by inserting a pin gauge. Further, in the wrist joint portion, as shown in FIG. 1 (c), a through groove (inspection groove 54) is passed through both the third arm (first inspection target component) 300 and the fourth arm (second inspection target component) 400 which are adjacent to each other. It is confirmed that the relative turning angle of the axis center of each arm 300, 400 is within a predetermined angle range by inserting a block gauge.

  The fitting between the inspection gauge and the through-hole or through-groove is precisely formed, so it has traditionally relied on the operator's hand feeling, but in this proposal the position using the robot that performs this insertion work Deviation inspection device was developed.

  FIG. 2 shows an overall view of a positional deviation inspection apparatus 1 according to the embodiment of the present invention. The inspection unit 3 is mounted as an end effector on a small 6-axis manipulator 2. A detailed view of the inspection unit 3 is shown in FIG. A vision sensor 5 having illumination 6 is attached to the wrist portion of the manipulator 2. Further, a pin gauge 8, a block gauge 9, and a block gauge 10 are attached to the tip portion via the force sensor 7. These three types of gauges are properly used depending on the inspection site, and when one gauge is used, the other gauges are arranged so that they do not become obstacles.

  Since this inspection is performed in an inspection process after the assembly of the robot 50 to be inspected is completed, the positional deviation inspection apparatus 1 is installed adjacent to the inspection line.

<Configuration of pin gauge and block gauge>
As shown in FIG. 6, the pin gauge 8 and the block gauge 10 used in the present invention are specially devised so that the inspection can be performed smoothly. First, as for the pin gauge 8, as shown in FIG. That is, the lower side in a state where C chamfering is performed so that the angle θ (angle formed with the axis) with the outer peripheral surface is in the range of 15 to 45 degrees, and the pin gauge 8 is completely inserted to the bottom of the inspection hole. The specifications of the C chamfering are set so that a contact portion between the inner periphery of the arm inspection hole and the outer periphery of the C chamfered non-machined portion of the pin gauge 8 is secured. As a result, the relative position inspection function of the pin gauge 8 is maintained, and the insertion function by the C chamfered portion allows smooth insertion regardless of precise fitting.

  Further, as shown in FIG. 6B, the block gauge 10 has a chamfered chamfered tip like the pin gauge 8 and has the same function as the pin gauge 8. Further, the block gauge 10 is configured such that a tip portion inserted into the first inspection target component and a tip portion inserted into the second inspection target component are separated from each other as shown in FIG. As a result, it is ensured by an operation suitable for the robot such that the first tip portion is inserted into the first inspection target component in the first operation and the other tip portion is inserted into the second inspection target component in the second operation. Can be inserted and inserted.

<Operation of misalignment inspection device>
Next, the inspection process will be described in order.
First, when the robot to be inspected 50 stops at a predetermined position on the line and a signal for starting inspection is transmitted from the control device of the line to the positional deviation inspection apparatus 1, the positional deviation inspection apparatus 1 performs an inspection according to a previously taught procedure. To start. In the inspection, the inspection gauges are used in order from the joint portions corresponding to the six degrees of freedom of the robot 50 to be inspected, that is, from the inspection portion 51 to the inspection portion 56 shown in FIG. An inspection is conducted, and a failure is determined if NG occurs even at one location.

  First, the manipulator 2 is operated in accordance with an operation instruction taught in advance, and the vision sensor 5 is brought close to the inspection hole of the first inspection region 51. The vision sensor 5 recognizes the exact position of the inspection hole, calculates an error from the position taught in advance, and corrects the subsequent operation instruction of the manipulator 2. This is the position correction process.

<Insertion operation of pin gauge 8>
Next, the manipulator 2 is operated in accordance with the operation instruction corrected as described above, and the tip of the pin gauge 8 is moved onto the central axis of the inspection hole to insert the pin gauge from the central axis. This is an insertion process. Details will be described with reference to FIGS. 4, 7 and 8.

  The fitting between the pin gauge and the inspection hole is precisely configured, so when the operator inserts it, a smooth inspection is performed by a hand-sensing exploration operation or a pass / fail judgment that feels the repulsive force. Yes. In order for the inspection apparatus to substitute for this work, a device / algorithm simulating the work by the worker is required.

In order to make the positional deviation detection device make a pass / fail judgment instead of the operator's visual or hand judgment, the present invention employs an algorithm based on the following three criteria.
A. Has the insertion operation been completed within a predetermined work time set in advance?
B. Did the insertion amount clear the reference value?
C. Has a reaction force exceeding the reference value occurred at the end of the work?
That is, in the pass / fail judgment of each inspection part, the pass judgment is made only when all of A to C are cleared, and in other cases, the judgment is made that the robot 50 to be inspected is removed from the line and readjustment / re-examination is performed.

  The insertion operation is performed by moving the manipulator 2 while applying a predetermined force in the axial direction. In this embodiment, the axial force is inspected by referring to the force actually applied by the operator. Is set taking into account the work efficiency of the system. Also, in normal insertion operation, interference between the pin gauge and the inspection hole at the entrance due to axial misalignment is unavoidable, and as described above, the pin gauge and block gauge have a gentle angle of 45 degrees or less with the outer peripheral surface. Chamfering is used to make use of the invitation effect. That is, if the shaft misalignment is small, the chamfered portion interferes with the inspection hole. Therefore, the force in the axial direction generates a component force in the direction for correcting the shaft misalignment, and this force is detected by the force sensor.

  As shown in FIG. 9, this force information is sent to the robot controller and fed back to the operation instruction to the manipulator. As described above, when a force in the direction perpendicular to the axis is generated, if the robot controller is programmed to correct the axial center position in a direction to reduce the force, the axis deviation is corrected autonomously. This is called a lure effect. FIG. 4 (a) shows this process, and FIG. 4 (b) shows a state in which the tip portion is inserted due to the enticing effect.

  Next, even after the tip portion is inserted, a reaction force is generated if the axial directions of the pin gauge and the inspection hole are misaligned. As shown in FIG. 4 (b), when a reaction force is generated due to an axial shift, the load is concentrated on the contact portion between the pin gauge and the inspection hole, and the friction coefficient becomes excessive, and the insertion operation is hindered by a large reaction force. Is done. In this case, since torque is generated in the pin gauge, the direction and magnitude of this torque are detected by the force sensor. As in the case of the invitation, as shown in FIG. 9, the force information is sent to the robot controller and fed back to the operation instruction to the manipulator. In this case, if the robot controller is programmed to finely correct the axial direction in the direction of decreasing the torque, the axial direction is corrected autonomously. This is the posture correcting means. In practice, this operation is repeated several times as shown in FIGS. 4 (b) to 4 (f) (this is called a posture correction step), and the pin gauge is gradually pushed in with a predetermined force. When the pin gauge penetrates the upper first inspection target component, insertion into the lower second inspection target component is started.

  Here, if the displacement between the first inspection target component and the second inspection target component is large, the tip of the pin gauge 8 and the opening of the inspection hole of the second inspection target component interfere with each other. In this case, since the pin gauge 8 is inserted into the first inspection target component and the movement in the direction perpendicular to the axis is restricted, interference cannot be avoided and the insertion operation is stopped. As shown in FIG. 7E, the acceptance / rejection determination in this case satisfies the C determination criterion because a reaction force is generated, but fails because the B insertion amount criterion is not satisfied.

  Conversely, if the deviation between the first inspection target part and the second inspection target part is sufficiently small, the portion of the pin gauge 8 that is not chamfered is pushed into the second inspection target part. And after clearing the reference | standard of the amount of insertion of B, as shown in FIG.7 (d), the front-end | tip of the pin gauge 8 reaches | attains the bottom part of the hole for a test | inspection of a 2nd test object component, and generate | occur | produces sufficient reaction force. . In this case, if the work is completed within a predetermined work time, all the criteria including A are cleared, and therefore, a pass determination is made as shown in FIG.

  The time limit for the predetermined work time of the reference A is provided mainly from the viewpoint of limiting the time required for the inspection. When the deviation between the first inspection target part and the second inspection target part is in a delicate range, the pin gauge may be gradually pushed in with a predetermined force and a pass determination may be made over time. From the viewpoint of quality control, first determine the range of deviation to be acceptable, and set the time limit for insertion operation and the axial pushing force to ensure that products exceeding that tolerance are rejected. The decision is made taking into account the constraints of the inspection time.

  FIG. 8 shows a list showing the relationship between A, B, and C and the pass / fail judgment. In addition to the state shown in FIG. 4, there are several patterns, but the pass judgment is performed only when all of A, B, and C are ◯.

<Block gauge insertion operation>
As shown in FIG. 3, in this embodiment, two types of block gauges 9 and block gauges 10 are attached to the inspection unit 3 in accordance with the shape of the inspection site. Since the operation is the same, the insertion operation using the block gauge 9 will be described.

  As shown in FIGS. 5 (a) to 5 (c), three methods were tried to insert the block gauge 9 into the inspection groove. First, as shown in (a), the block gauge 9 is arranged on the extension line of the axis of the inspection groove, and is inserted along the axis from one end of the inspection groove. Next, as shown in (b), the block gauge 9 is arranged in parallel with the inspection groove, and is inserted while keeping parallel from the opening direction of the inspection groove. As a result of the experiment, neither the method (a) nor the method (b) was able to be stably inserted into various misalignment states. As a cause, it was speculated that the input to the force sensor would be complicated due to the difference in the shape of the mating part, and unlike the case of the pin gauge, there were multiple or wide contact surfaces.

  Next, as shown in (c), the tip portion inserted into the inspection groove of one arm and the tip portion inserted into the inspection groove of the other arm are configured to be separated from each other. Was inserted (referred to as the first insertion step) and then the other tip portion was inserted (referred to as the second insertion step). The method of sequentially performing the first insertion step and the second insertion step makes it possible to stably insert the gauge, and the requirement A within a predetermined work time can be cleared. Therefore, this method is adopted for the inspection site where the block gauge is inserted into the inspection groove. In the first insertion step, the robot is operated in accordance with the corrected operation instruction, the block gauge is moved so as to face the inspection groove, and then the block gauge is inserted into the inspection groove of the first inspection target component. This is a step of inserting one tip portion of the tip. The second insertion step is a step of inserting the other tip portion of the block gauge tip into the inspection groove of the second inspection target component.

  By the method described above, the pass / fail judgment is made in order from the part close to the installation surface for all the test parts 51 to 56 shown in FIG. 1, and in the case of all the pass judgments, the relative position initial setting of each arm is judged as pass To do. If even one place is judged as unacceptable, the inspected robot 50 is sent to the readjustment / re-inspection process together with the inspection / determination data.

  As mentioned above, although the Example of this invention was described, this invention is not limited to an above-described Example, It can change and implement suitably. In this embodiment, the positional deviation inspection apparatus is applied to the inspection apparatus in the initial state of the robot according to the present invention. However, the present invention is not limited to this, and can be used for various product inspections in which inspection is performed using an inspection gauge. I can do it.

DESCRIPTION OF SYMBOLS 1 Position shift inspection apparatus 2 Manipulator 3 Inspection unit 5 Vision sensor 6 Illumination 7 Force sensor 8 Pin gauge 9 Block gauge 10 Block gauge 50 Robot to be inspected 51-56 Inspection part

Claims (5)

By inserting the pin gauges into the inspection holes formed in the first inspection target part and the second inspection target part that overlap each other, or the block gauges on the first inspection target part and the second inspection pair part adjacent to each other. A misalignment inspection device for determining whether or not the relative position between the first inspection target component and the second inspection target component is within a reference range by being inserted into the formed inspection groove,
A manipulator installed adjacent to a line on which a product including the first inspection target part and the second inspection target part is manufactured;
A vision sensor mounted on the manipulator so that the accurate position can be recognized by photographing the inspection hole or the inspection groove from a close position;
An end effector that is provided at the tip of the manipulator via a force sensor and is mounted so that a pin gauge and a block gauge used for positional deviation inspection can be used selectively;
When a reaction force is detected by the force sensor, a change in posture for continuing the insertion operation of the pin gauge, block gauge, and the inspection target component is calculated from the direction and magnitude of the reaction force, and the posture is reduced. Posture correction means for changing the amount;
An apparatus for inspecting misalignment. The tip portion of the pin gauge is chamfered with a surface having an angle of 15 to 45 degrees with respect to the outer peripheral surface, and a guiding shape is formed.
The misalignment inspection apparatus according to claim 1. The tip end portion of the block gauge is chamfered with a surface having an angle of 30 to 45 degrees with respect to the side surface, and the tip end portion to be inserted into the first inspection target component and the tip end to be inserted into the second inspection target component The parts are configured to be separated from each other,
The misalignment inspection apparatus according to claim 1. By inserting pin gauges into inspection holes formed in the first inspection target component and the second inspection target component that overlap each other, the relative position between the first inspection target component and the second inspection target component is within a reference range. A positional deviation inspection method for determining whether or not the
Operate the robot to bring the vision sensor closer to the first inspection target part or the second inspection target part, recognize the exact position of the inspection hole, calculate the error from the position taught in advance, A position correction step for correcting the subsequent robot movement instructions in response to the error;
An insertion step of operating the robot according to the corrected operation instruction, moving the pin gauge tip onto the central axis of the inspection hole, and inserting the pin gauge from the central axis;
When the pin gauge and the inspection hole come into contact with each other during insertion, the direction and magnitude of the reaction force is detected by the force sensor, and the amount of change in the posture of the pin gauge required to reduce the reaction force is calculated. A posture correction step for changing the posture of the pin gauge by a small amount;
A positional deviation inspection method characterized by comprising: By inserting the block gauge into the inspection grooves formed in the first inspection target component and the second inspection target component adjacent to each other, the relative position between the first inspection target component and the second inspection target component is within a reference range. A positional deviation inspection method for determining whether or not the
Operate the robot to bring the vision sensor closer to the first inspection target component or the second inspection target component, recognize the exact position of the inspection groove, calculate the error from the previously taught position, Correspondingly, a position correction process for correcting the subsequent movement instruction of the robot,
After the robot is operated according to the corrected operation instruction and the block gauge is moved so as to face the inspection groove, one end portion of the block gauge tip is placed in the inspection groove of the first inspection target component. A first insertion step for insertion;
A second insertion step of inserting the other tip portion of the block gauge tip into the inspection groove of the second inspection target component;
A positional deviation inspection method characterized by comprising:

Images