JP2012232384A - Inspection device and inspection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inspection device capable of correctly inspecting the success and failure of component assembling work.SOLUTION: The inspection device includes: a force acquisition means for acquiring a force acted on a robot end effector; a position acquisition means for acquiring the position of the robot end effector; a segmenting means for segmenting a partial waveform of an inspection range from a waveform indicating a relationship between the acquired force and the acquired position; an inspection range specification means for specifying an inspection range to be segmented by the segmenting means; an extreme value recognition means for recognizing a plurality of extreme values of the partial waveform segmented by the segmenting means; a determination means for selecting a maximum value and a minimum value to be inspected from the plurality of recognized extreme values according to a basis of selection to determine whether a difference between the maximum value and the minimum value satisfies a criterion; an inspection parameter specification means for specifying the basis of selection and the criterion to be used by the determination means; and an inspection output means for outputting a signal indicating the success or failure of the work according to the determination result of the determination means.

Description

  The present invention relates to an inspection apparatus and an inspection method.

  In a robot for assembling parts, a force sensor is provided at the tip of the hand, and a method for inspecting work using force information detected by the force sensor has been proposed.

  In Patent Document 1, in a connector pin insertion device that inserts a pin into a pin hole of a connector, whether or not the pin is properly inserted into the pin hole by comparing the change pattern of the insertion force acting on the pin with the reference change pattern. It is described to determine whether or not. Thus, according to Patent Literature 1, it is possible to inspect whether or not a pin is inserted without using a component such as an actuator that does not contribute to the insertion of the pin at all.

  In Patent Document 2, in a press-fitting system in which a work member is press-fitted by a plunger into a press-fitted member having a press-cut end, a plurality of positions in front of the press-fitting end position are set as a plurality of check points, respectively. It is described that it is determined whether or not the pressure input by is within a predetermined range at each of a plurality of check points. As a result, according to Patent Document 2, there is no variation in determination due to variation in the push-off end, and accurate press-fitting determination is performed.

JP 2004-1119046 A JP 2007-260905 A

  However, in the conventional method, if the insertion operation position is shifted, the workpiece position is shifted, or the absolute value of the force acting due to the difference in lots is different, the success of the operation is erroneously determined as failure, and the part There is a possibility that the success or failure of the assembly work cannot be correctly inspected.

  For example, in the method described in Patent Document 1, when the work installation position is shifted in the vertical direction, the pattern of the insertion force is shifted from the reference pattern.

  Or, for example, in the method described in Patent Document 2, there is a case where the installation position of the workpiece is shifted in the horizontal direction, or the absolute value of the reaction force acting due to the difference in lot may be different. Since the magnitude of the reaction force at the check point is significantly different from the value measured in advance, there is a possibility of erroneous determination as failure even when the work is successful.

  The present invention has been made in view of the above, and an object of the present invention is to obtain an inspection apparatus and an inspection method capable of correctly inspecting the success or failure of component assembly work.

  In order to solve the above-described problems and achieve the object, an inspection apparatus according to one aspect of the present invention is an inspection apparatus that inspects whether a part assembly operation by a robot is successful or unsuccessful. A portion of the inspection range from the force acquisition means for acquiring the force acting on the robot tip, the position acquisition means for acquiring the position of the robot tip, and the waveform indicating the relationship between the acquired force and the acquired position. Cutout means for cutting out a waveform, inspection range specifying means for specifying an inspection range to be cut out by the cutout means, extreme value recognition means for recognizing a plurality of extreme values in the partial waveform cut out by the cutout means, and the recognition A local maximum value and a local minimum value to be inspected are selected from a plurality of measured extreme values according to a selection criterion, and a difference between the local maximum value and the local minimum value satisfies a determination criterion. A determination means for determining whether or not, an inspection parameter specifying means for specifying a selection criterion and a determination criterion to be used in the determination means, and a signal indicating success or failure of the work according to a determination result by the determination means And an inspection output means.

  According to the present invention, the inspection range for determining success / failure of work by the inspection range specifying means can be widely specified so that the feature (extreme value) is included. The success or failure of the assembly work of the parts can be determined for the partial waveform in the included inspection range. Therefore, it is possible to correctly inspect the success or failure of the part assembly operation.

FIG. 1 is a diagram illustrating a configuration of the inspection apparatus according to the first embodiment. FIG. 2 is a diagram illustrating an example of a force graph detected by the inspection apparatus according to the first embodiment. FIG. 3 is a diagram illustrating an operation of the inspection apparatus according to the first embodiment. FIG. 4 is a flowchart illustrating the operation of the inspection apparatus according to the first embodiment. FIG. 5 is a diagram for explaining the operation of the extreme value recognition means in the first embodiment. FIG. 6 is a diagram illustrating an operation of the inspection apparatus according to the first embodiment. FIG. 7 is a diagram showing the operation of the display means in the first embodiment. FIG. 8 is a diagram illustrating a configuration of the inspection apparatus according to the second embodiment. FIG. 9 is a diagram illustrating a configuration of the inspection apparatus according to the third embodiment. FIG. 10 shows the operation of the display means in the third embodiment. FIG. 11 is a diagram showing the operation of the display means in the sixth embodiment.

  Embodiments of an inspection apparatus according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
An inspection apparatus 100 according to the first embodiment will be described with reference to FIG. FIG. 1 is a block diagram illustrating a configuration of the inspection apparatus 100.

  In the assembly work (automatic assembly work) of parts by the robot 1, the inspection apparatus 100, for example, confirms normal completion of work, bad assembly, biting of a cable, etc., for example, the force acquired by the force sensor 2a or the position sensor 3a. Automatic detection using information about changes. Specifically, the inspection apparatus 100 includes a robot 1, a force acquisition unit 2, a position acquisition unit 3, an acquisition condition designation unit 4, an inspection unit number selection unit 5, an inspection parameter designation unit 7, an inspection range designation unit 8, and a cutout unit. 9, inspection means 6, inspection output means 10, and display means 11.

  The robot 1 includes a single-axis or multi-axis motor (not shown), and examples thereof include a 6-axis vertical articulated robot called an industrial robot and a 4-axis horizontal articulated robot.

  In the force acquisition means 2, a force sensor 2a for detecting the force and moment acting on the vicinity of the tip of the robot 1 or on the object on which the robot works is attached. That is, the force acquisition unit 2 acquires a force acting on the tip of the robot 1 by detecting a force and a moment with the force sensor 2a. The force acquisition unit 2 supplies the acquired force as a force detection value to the inspection unit 6 and the display unit 11 via the robot 1 and the cutout unit 9.

  When the force sensor 2a is a six-axis force sensor, the force detection value is a force in three axes and a moment around each axis. When the force sensor 2a is a force sensor having five or less axes, the force detection value in the three axes Of the forces and moments around each axis, this is a measurable moment. In the force acquisition means 2, force sensors 2a are provided for each axis and for each moment, for example, and each force sensor 2a transmits a force detection value to the inspection means 6 and the display means 11, respectively.

  In the position acquisition means 3, a position sensor 3 a that measures the motor position of each axis such as an encoder or resolver is attached to correspond to the motor of each axis that drives the robot 1. That is, the position acquisition means 3 acquires the position of the tip of the robot 1 by detecting the motor position of each axis with the position sensor 3a and converting it into a position that can be internally processed by coordinate conversion processing. The position acquisition unit 3 supplies the acquired position as a position detection value to the inspection unit 6 and the display unit 11 via the robot 1 and the clipping unit 9.

  The acquisition condition designating unit 4 designates a sampling period, a detection start point, and an end point of data used in the force / position detection process by the force acquisition unit 2 / position acquisition unit 3. For example, the following command is executed and specified in the robot program describing the operation of the robot 1.

      FsTCond On, 1

  Here, “FsTCond On” is a robot language (command) for designating a detection start point, and “1” is a data cycle number used in the inspection process. For example, when the number is “1”, the data cycle used in the inspection process is SampT milliseconds.

      FsTest On, 30

  Here, “FsTest On” is a robot language (command) for designating a detection start point by the ratio of the movement distance from the operation start point, and “30” is a force / position detection at a point 30% from the start of the assembly operation. Specifies that starts.

      FsTest Off, 50

  Here, “FsTest Off” is a robot language (command) for designating a detection end point by the rate of movement distance from the operation start point, and “50” is a force / position detection at a point 50% from the start of the assembly operation. Specifies that is terminated.

  In this embodiment, the start point and the end point of force / position detection are specified by the ratio of the movement distance from the operation start point, but the ratio of the movement distance to the operation end point, the movement distance from the operation start point, You may specify with the movement distance to an operation | movement end point, the elapsed time from an operation | movement start, etc.

  The inspection means number selection means 5 designates the coordinate axis to be inspected and selects the inspection means number according to the type of work to be performed by the robot 1. The inspection means number is a number for designating an inspection means used as the inspection means 6. That is, there are a plurality of inspection means as candidates for the inspection means 6 in the inspection apparatus 100, and the inspection means number selection means 5 is used as the inspection means 6 from the plurality of inspection means by selecting the inspection means number. Specify the inspection method. The inspection means number selection means 5 supplies the information on the coordinate axes to be inspected to the designated inspection means 6 and supplies the inspection means number to the inspection parameter designation means 7.

  For example, when the work to be performed by the robot 1 is insertion of a resin cover of an electrical component, the inspection means number selection means 5 selects “51” as the inspection means number. For example, when the work to be performed by the robot 1 is connector insertion, the inspection means number selection means 5 selects “52” as the inspection means number.

  Further, for example, when the work to be performed by the robot 1 is insertion of a resin cover of an electrical component, for example, the following command is executed and specified in a robot program describing the operation of the robot 1.

      FsTAlgo, 51, 3

  Here, “FsTALGo” is a robot language (command) for designating the inspection means used in the inspection process, “51” is the inspection means number to be used, and “3” is the execution target of the inspection means number (inspection) Specify the Z-axis as the target axis.

  As described above, when the robot 1 has a plurality of axes, the axis having the clearest feature of the force information is not limited to the force information in the work direction, and the force information is characterized for the success or failure of the work according to the type of the assembly work. You can choose. Thereby, the reliability of a test | inspection can be improved.

  The inspection parameter designation means 7 receives the inspection means number from the inspection means number selection means 5. At this time, a combination of inspection parameters for each inspection means number is stored in advance in the storage means M, for example, and the inspection parameter designation means 7 refers to the storage means M and acquires a combination of inspection parameters corresponding to the inspection means number. To do. The inspection parameter specifying unit 7 specifies the acquired combination of inspection parameters as an inspection parameter to be used and supplies it to the inspection unit 6.

  In this embodiment, the designated inspection means number is designated, and then the inspection parameter corresponding to the inspection means number is acquired and designated as the inspection parameter to be used. It may be described directly by a program instruction.

  The inspection range specifying unit 8 specifies the inspection range to be cut out by the cutout unit 9. In other words, the inspection range designating unit 8 designates an inspection range for causing the inspection unit 6 to recognize the feature (extreme value) in the force waveform in order to determine the success or failure of the fitting work, for example. That is, the inspection process start data and the inspection process end data to be inspected by the inspection unit 6 with respect to force / position data which is a collection of force / position detection values detected by the force acquisition unit 2 / position acquisition unit 3 Is specified. The designation of the inspection process start point and the inspection process end point can be specified by the Cartesian coordinate position of the robot, but it is not possible to perform the inspection including the reversing operation in the assembly work. The total time from the beginning to the end of the force / position data detected by the robot 1 is set as 100%, and the ratio is specified as a percentage. The head of the force / position data detected by the force acquisition unit 2 / position acquisition unit 3 is 0% and the last is 100%. For example, the following command is executed and specified in the robot program describing the operation of the robot 1.

      FsTBat, 70, 100

  Here, “FsTBat” is a robot language (command) for designating the inspection processing start rate and the inspection processing end rate, and “70, 100” is the force / position detected by the force acquisition unit 2 / position acquisition unit 3. It specifies that the inspection process starts at 70% of the total time from the beginning to the end of the data and ends at 100%.

  The cutout unit 9 cuts out a partial waveform of the inspection range specified by the inspection range specifying unit 8 from the waveform indicating the relationship between the force acquired by the force acquisition unit 2 and the position acquired by the position acquisition unit 3. That is, the cutout unit 9 cuts out a partial waveform of the inspection range specified by the inspection range specifying unit 8 from the force / position data detected by the force acquisition unit 2 / position acquisition unit 3.

  In this way, in the force / position data (overall waveform) detected by the force acquisition means 2 / position acquisition means 3 for the robot 1 for the assembly work, the portion having the feature point of the force information that can determine the success / failure of the work is represented by FsTBat. It can be within the specified inspection processing range (partial waveform). That is, since information that is not related to the inspection is excluded and processed, the inspection processing time can be shortened. In addition, there are cases where similar features are found when a full range inspection is performed, but such erroneous determination can be prevented by narrowing down the range.

  The inspection means 6 is an inspection means designated by selecting an inspection means number with the inspection means number selection means 5. The inspection unit 6 includes, for example, an extreme value recognition unit 61 and a determination unit 62. The inspection means 6 receives information on the coordinate axes to be inspected from the inspection means number selection means 5 and receives inspection parameters to be used from the inspection parameter designation means 7. The inspection unit 6 performs an inspection process using the inspection parameters on the coordinate axes to be inspected, and for example, the inspection output unit 10 and the display unit use the determination result as to whether the assembling work has succeeded or failed. 11 to output. The configuration and processing means inside the inspection means are different for each inspection means number. For example, the processing procedure of the inspection means corresponding to the fitting operation of a part having a claw portion for preventing detachment will be described later.

  The inspection output means 10 outputs a signal indicating the success or failure of the work by opening / closing the hand or causing the LED to emit light at the end of the work using the determination result of the inspection means 6. In this way, by informing the production manager, other control devices, etc. through the I / O etc. of the inspection result such as the determination result by the inspection means 6, it is possible to notify the occurrence of the assembly failure product in real time.

  The display unit 11 displays, for example, a graph display of force / position data detected by the force acquisition unit 2 / position acquisition unit 3, an inspection result by the inspection unit 6, and force / position information of feature points. For example, the display unit 11 displays the position of the robot tip and the magnitude of the force when the force maximum value is generated.

  In FIG. 1, the inspection means number selection means 5 except the robot 1, inspection parameter designation means 7, inspection range designation means 8, cutout means 9, inspection means 6, inspection output means 10, and display means 11 are, for example, one. The storage means M may be a memory (including ROM, RAM, etc.) in the computer shared by each means.

  Next, the operation of the inspection apparatus 100 will be described. Below, the automatic inspection of the fitting operation | work of the component with a nail | claw part for the purpose of prevention | removal prevention is mentioned as an example, and is demonstrated.

  Before automating the assembly work inspection process, set up for inspection. Specifically, after executing a program for performing an assembly work operation on the robot 1, the force / position data detected by the force acquisition unit 2 / position acquisition unit 3 is displayed as a graph on the display unit 11. The inspection unit number selection unit 5, the inspection parameter designation unit 7, and the inspection range designation unit 8 are set according to the graph on the display unit 11 and its output value. That is, the robot program for performing the assembly work operation is executed, the graph of the force / position data detected by the force acquisition unit 2 / position acquisition unit 3 is confirmed with respect to the robot 1, the inspection range is designated, and extracted. The inspection means number adapted to the characteristics of the force waveform is selected, and a parameter corresponding to the selected inspection means number is set.

  FIG. 2 is an example of a force detection graph when the fitting operation is successful. The vertical axis represents the detection force (inspection axial force), and the horizontal axis represents the ratio of the time from the start of the inspection when the time from the start to the end of the inspection is 100%. As shown in FIG. 2, the characteristic force information portion corresponding to the fitting operation is such that the claw portion 41 for preventing detachment in the cover portion 40 fits into the hole portion 51 in the base portion 50 (see FIG. 3D). This is force information before and after the moment, and is a portion indicated by a dotted frame 12. That is, the force increases while the disengagement-preventing claw portion 41 is fitted in the hole portion 51 (see FIGS. 3A and 3E), and the detection force has a peak value at the moment when the claw portion 41 is fitted in the hole portion 51. become. Further, immediately after the claw portion 41 is fitted in the hole portion 51, the detection force decreases (see FIGS. 3B and 3F) and increases again after reaching the minimum value (FIGS. 3C and 3G). )reference).

  In other words, with regard to the work of fitting the part having the claw part 41 for preventing the disengagement into the hole part 51, when the fitting is successful, the force sensor value temporarily decreases suddenly when the claw part 41 fits into the hole part 51. It can be seen from FIG. 2 and FIG. 3 that the “power loss phenomenon” occurs. As shown in FIG. 3, since the physical contact is suddenly lost from the state in which the resultant force of the friction and the reaction force is received in the axial direction in which the fitting is advanced, a significant change in the force is generated in the direction in which the insertion is advanced. This is a phenomenon that occurs if the same mechanism is used.

  As shown in FIG. 2, in order to extract such a phenomenon from a trough portion of the force waveform characteristic of fitting, the inspection range specifying means 8 specifies the dotted frame 12 shown in FIG. 2 as the inspection range. That is, the inspection process start point Per1 and the inspection process end point Per2 in the inspection unit 6 are sequentially designated. The purpose of the inspection range specification by the inspection range specifying means 8 is that, as shown in FIG. 2, if the entire waveform is inspected, a partial waveform similar in profile to the partial waveform in the dotted line frame 12 is found and erroneously determined. Therefore, it is possible to prevent such erroneous determination by narrowing down the inspection range.

  Next, the inspection means corresponding to the fitting operation of the part having the claw portion 41 for preventing detachment is selected by the inspection means number selection means 5. For example, “51” is selected as the inspection means number. The inspection means number “51” designates an inspection means that automatically determines whether the fitting operation of a part having a claw portion 41 for preventing detachment as shown in FIG. 3 has succeeded or failed.

  A flowchart for explaining the sequence of the inspection means number 51 is shown in FIG. Before describing FIG. 4, the operation of the extreme value recognition means 61 for recognizing the extreme value of the waveform of the force detection value will be described. In reality, a waveform that fluctuates due to noise or the like may be regarded as an extreme value. The extreme value recognition means 61 can recognize the extreme value of the waveform of the force detection value by, for example, filter processing using a filter. However, if the filter passes through the filter, the original feature point may be lost or difficult to discriminate. There is a possibility of becoming. Therefore, in order to recognize the extreme value accurately and stably, the following conditions are set for the extreme value recognition means 61.

  (A) A point where there is an increase / decrease change in force before and after all, that is, a point where the sign of the rate of change in the derivative of the discrete force data point changes as shown in FIG. 5 is recorded as a candidate extreme value. For example, the x points shown in FIG. 5 are all the candidate extreme values EV1 to EV8.

  (B) The current force is F (k), and the number of consecutive extreme value recognitions is F_Slope_Width. For example, if F_Slope_Width is 3, it becomes +++ --- or --- ++++. If there is 0 (no increase or decrease in force) during the determination, a specific number, for example, 2 is allowed, but any number can be entered in the following equation. This condition (b) includes a condition (b.1) for recognizing it as a maximum value and a condition (b.2) for recognizing it as a minimum value, as described below.

  (B.1) In the case of F (k) −F (k−1) <0, F (k−1) is recognized as a local maximum if the following mathematical expressions (1) to (4) are satisfied simultaneously. The

F (k + i) −F (k + i−1) ≧ 0
(I =-(F_Slope_Width + ZeroL), ..., -2, -1)
... (1)

F (k-1) -F (k-1-F_Slope_Width-ZeroL)
≧ F_Slope_High (2)

F (k + i) −F (k + i−1) ≦ 0
(I = 1, 2,..., (F_Slope_Width + ZeroR) −1)
... (3)

F (k-1) -F (k-1 + F_Slope_Width + ZeroR)
≧ F_Slope_High (4)

  However, ZeroL is the number of data with no increase / decrease in force on the left side in the extreme force graph, and ZeroR is a point with no increase / decrease in force on the right side in the extreme force graph. F_Slope_High is an extreme value recognition allowable threshold, and a condition that a difference before and after the extreme value is a certain value or more can be added. Under this condition, it is possible to ensure the inclination of the recognized extreme left and right force waveforms.

  The meaning of each formula is as follows, for example.

  Formula (1): The candidate maximum value has never decreased from the (F_Slope_Width + ZeroL) -th force data before the occurrence to the candidate maximum value F (k−1).

  Formula (2): The difference between the candidate maximum value F (k−1) and the force data of the (F_Slope_Width + ZeroL) time before the generation of the candidate maximum value is greater than or equal to F_Slope_High.

  Formula (3): Force data has never increased continuously (F_Slope_Width + ZeroR) times after the candidate maximum F (k−1) is generated.

  Formula (4): The difference between the candidate maximum value F (k−1) and the force data of the (F_Slope_Width + ZeroR) times after the generation of the candidate maximum value is greater than or equal to F_Slope_High.

  If the above conditions are satisfied, the candidate maximum value F (k−1) is recognized as the maximum value.

  (B.2) In the case of F (k) −F (k−1)> 0, F (k−1) is recognized as a minimum value if the following mathematical expressions (5) to (8) are satisfied simultaneously. The

F (k + i) −F (k + i−1) ≦ 0
(I =-(F_Slope_Width + ZeroL), ..., -2, -1)
... (5)

F (k-1) -F (k-1-F_Slope_Width-ZeroL)
≦-(F_Slope_High) (6)

F (k + i) −F (k + i−1) ≧ 0
(I = 0, 1, 2,..., (F_Slope_Width + ZeroR) −1)
... (7)

F (k-1) -F (k-1 + F_Slope_Width + ZeroR)
≦-(F_Slope_High) (8)

  In the case shown in FIG. 5, the candidate extreme value EV2 is not recognized as an extreme value. The reason is that the force change height h1 before and after the candidate extreme value EV2 exceeds F_Slope_High, but the discrete force data rising point w1 is smaller than F_Slope_Width between the candidate extreme value EV2 and the candidate extreme value EV3. For the same reason, the candidate extreme value EV3 is not recognized as an extreme value.

  Further, the candidate extreme value EV8 is not recognized as an extreme value. This is because the discrete force data drop point w2 is larger than F_Slope_Width between the candidate extreme value EV7 and the candidate extreme value EV8, but the force change height h2 before and after the candidate extreme value EV8 is smaller than F_Slope_High. For the same reason, the candidate extreme value EV7 is not recognized as an extreme value.

  As described above, the extreme value recognition means 61 recognizes the extreme values EV1, EV4, EV5, EV6, for example, using the extreme value recognition parameters of the extreme value recognition continuous number and the extreme value recognition allowable threshold.

  Next, a sequence for determining the presence or absence of the force loss phenomenon will be described with reference to FIG.

  First, the determination means 62 sets “failure” as the default value of the determination result (step S10).

  Thereafter, the cutout unit 9 cuts out the partial waveform of the inspection range specified by the inspection range specifying unit 8 from the force / position data (whole waveform) detected by the force acquisition unit 2 / position acquisition unit 3 (step S11). . For example, the cutout unit 9 cuts out the partial waveform in the dotted frame 12 shown in FIG. The clipping unit 9 supplies the clipped partial waveform data to the extreme value recognition unit 61.

  The extreme value recognizing means 61 performs the partial waveform of the force detection value in accordance with the above conditions (conditions (a), (b), (b.1), (b.2), equations (1) to (8)). A plurality of extreme values are recognized (step S12). The extreme value recognizing means 61 supplies a plurality of recognized extreme value data to the determining means 62.

  Next, the determination unit 62 determines whether or not the local maximum value and the local minimum value are both in the extreme value detected in step S12 (that is, whether or not “minimum value number ≧ 1 & maximum value number ≧ 1” is satisfied). ) And at least one of them is absent (No in step S13), the inspection process is terminated. If both exist (Yes in step S13), the determination unit 62 recognizes the maximum value Fmax among the maximum values (step S14).

  Next, the determination unit 62 determines whether or not the minimum value exists after the maximum value Fmax among the maximum values. If the minimum value does not exist (No in step S15), the determination unit 62 ends the inspection process and exists. If yes (Yes in step S15), the nearest minimum value after Fmax is specified, and the result is set as Fpeakmin (step S16).

  Next, the determination means 62 determines whether or not Fpeakmin is the first extreme value after Fmax. If it is not the first extreme value, that is, if a maximum value exists between Fmax and Fpeakmin (step In S17, the inspection process is terminated. Further, when the determination unit 62 is the first extreme value, that is, when the maximum value Fmax of the maximum value occurs and the next extreme value is the minimum value (Yes in step S17), the difference between Fmax and Fpeakmin is determined. And the calculation result is MaxMinDiff (step S18).

  For example, if the force waveform varies depending on the workpiece and the teaching point, and the MaxMinDiff value varies, as shown in FIGS. 6A to 6G, when the claw portion 42 for preventing detachment has a defect, Even if the force loss phenomenon (a phenomenon in which the force sensor value is temporarily decreased suddenly when the claw part 42 is fitted in the hole part 52) can be detected, the value of MaxMinDiff is too small, and a defective product is generated. Therefore, a determination threshold value FMaxmin is introduced for determining whether the product is defective and determining success / failure within a range in which variation is considered.

  That is, the determination unit 62 compares MaxMinDiff with the determination threshold value FMaxmin, and when MaxMinDiff does not exceed the determination threshold value FMaxmin (No in step S19), the inspection process ends. Further, when MaxMinDiff exceeds the determination threshold value FMaxmin (Yes in step S19), the determination unit 62 determines that the determination result is successful and determines that the assembly work is successful (step S20).

  Thereafter, the determination unit 62 of the inspection unit 6 supplies, for example, the determination results in steps S10 to S20 to the inspection output unit 10 and the display unit 11 as the inspection results.

  In this way, it is possible to automatically determine whether the fitting operation of the part with the claw portions 41 and 42 for preventing the detachment as shown in FIGS. 3 and 6 is successful or unsuccessful.

  In the processing shown in FIG. 4, parameters necessary for designation by the inspection parameter designation unit 7 are, for example, the number of consecutive extreme value recognitions, an extreme value recognition allowable threshold value, and a determination threshold value. In the processing shown in FIG. 4, attention is paid to the difference between the maximum value Fmax among the maximum values and the minimum value Fpeakmin when the closest extreme value after the occurrence of Fmax is the minimum value. The difference between the maximum value Fmax in the maximum value and the second minimum value after the occurrence of Fmax, for example the second maximum value after the maximum value Fmax in the maximum value has occurred, For example, a difference from the third minimum value after the maximum value Fmax among the maximum values has occurred may be noted.

  As described above, in the first embodiment, a specific portion (partial waveform) necessary for determining the success or failure of a work in a force waveform is cut out, a plurality of extreme values in the partial waveform are recognized, and a plurality of extreme values are determined according to selection conditions. Then, the local maximum value and the local minimum value to be inspected are selected, and it is determined whether or not the difference between the local maximum value and the local minimum value satisfies the criterion. For this reason, even if the work position or the work position of the robot 1 is shifted, the inspection range for determining the success / failure of the work by the inspection range specifying means 8 can be specified widely so as to include the feature (extreme value). The success or failure of the part assembly operation can be determined for the partial waveform in the inspection range that reliably includes the characteristics of the force waveform for determination. Alternatively, as shown in FIG. 7, the assembly work is complicated, and it is difficult to determine the success or failure of the work only by paying attention to the “insertion force change pattern” because the force pattern other than the specific region changes for each work. Even in this case, since the inspection range for determining the success / failure of the work can be specified widely so that the feature (extreme value) is included by the inspection range specifying means 8, the feature of the force waveform for determining the success / failure of the work is surely included. The success or failure of the part assembly operation can be determined for the partial waveform in the inspection range. Therefore, it is possible to correctly inspect the success or failure of the part assembly operation.

  In the first embodiment, the feature of the force waveform, that is, the extreme value in the partial waveform in the inspection range is recognized, and the maximum value and the minimum value to be inspected are selected from a plurality of extreme values according to the selection conditions. The success or failure of the work is determined by comparing the difference between the maximum value and the minimum value with a determination threshold value. Thereby, the success or failure of the work can be accurately determined, and the success or failure of the assembly work of the parts can be correctly inspected.

  At the same time, defective products can be prevented from passing. That is, the inspection range can be specified by the inspection range specifying means 8 so as to exclude a portion unrelated to the inspection as much as possible, and processing for removing the extreme value due to noise using the extreme value recognition parameter is performed when setting the extreme value. be able to. Further, the low-pass filter sometimes eliminates a necessary force waveform, but this can be avoided.

  Further, in the first embodiment, as shown in FIG. 7, the display means 11 is a parameter setting value, a graph of force data detected by a work operation, an inspection range, an extreme value recognition result, a recognized feature point, an inspection result, etc. Can be displayed. This facilitates selection of inspection means numbers and setting of inspection parameters, and facilitates evaluation of inspection results. For example, in FIG. 7B, the extreme value recognition allowable threshold F_Slope_High is set larger than that in FIG. That is, it can be seen that the extreme values recognized are reduced when the extreme value recognition conditions become severe. As described above, since the influence of the parameter setting on the inspection result is easy to understand, it is possible to clearly specify the parameter by the inspection parameter specifying means 7 and to shorten the inspection parameter setting time.

Embodiment 2. FIG.
Next, the inspection apparatus 200 according to the second embodiment will be described. Below, it demonstrates focusing on a different part from Embodiment 1. FIG.

  The inspection apparatus 200 further includes an input unit 220. Further, the operations of the inspection means number selecting means 5, the inspection range specifying means 8, and the inspection parameter specifying means 7 are different from those of the first embodiment.

  That is, the input unit 220 receives an instruction for changing at least one of the selection criterion and the determination criterion to be specified by the inspection parameter specifying unit 7. The inspection parameter specifying means 7 changes at least one of the selection criterion and the determination criterion according to the instruction. Alternatively, the input unit 220 receives an instruction for changing the inspection range to be specified by the inspection range specifying unit 8 and supplies the instruction to the inspection range specifying unit 8. The inspection range designating unit 8 changes the inspection range according to the instruction.

  For example, the above-described command parameters (inspection process start data and inspection process end data) sent from the inspection range specifying means 8 to the cutout means 9 are input to the input means I comprising a manual operation panel or a personal computer connected to a computer, for example. Rewrite the value via

  For example, when the parameter value of the above FsTBat is set to FsTBat (70, 100), the clipping unit 9 starts from a point exceeding 70% of the total time from the beginning to the end of the force / position data (whole waveform). Cut out data (partial waveform) up to% point.

  As described above, according to the second embodiment, the parameter of the instruction can be designated immediately before the operation by the input from the input unit I, so that it can be set finely for each operation.

Embodiment 3 FIG.
Next, an inspection apparatus 300 according to the third embodiment will be described. Below, it demonstrates focusing on a different part from Embodiment 1. FIG.

  The inspection apparatus 300 further includes scoring means (evaluation means) 330. The scoring means 330 performs, for example, scoring the teaching points for the robot 1 based on the difference between the maximum value and the minimum value and the determination criterion.

When re-teaching is necessary, for example, when a workpiece is exchanged at the production site, the quality of the re-teaching point of the work is scored using the inspection result by the inspection means 6. The evaluation index of the inspection result varies depending on the number designated by the inspection means number selection means 5. For example, in the fitting operation of the part having the claw portion for preventing detachment described in the first embodiment, the evaluation score of the teaching point is expressed as follows: teaching score evaluation score = (MaxMinDiff) / (FMaxmin) (9)
Can be calculated with

  However, MaxMinDiff is the difference between the actual maximum feature value, that is, the maximum maximum value and the minimum value, and FMaxmin is a determination threshold value for determining the success / failure of work in consideration of component variations. Then, when the teaching point evaluation score is 1.0, it is a limit for recognizing the work as a success. When the work teaching points are taught well, the fitting work can be performed well, and the teaching point evaluation score increases.

  For example, FIG. 10A shows an example of display contents when the inspection result is displayed on the display means 11 before the workpiece is exchanged. In the case of FIG. 10A, the average value of the teaching point evaluation taking account of component variations is 3.2. FIG. 10B shows a display content example when the inspection result is displayed on the display means 11 after re-teaching. In the case of FIG. 10B, since the teaching point evaluation is only 1.1, it is considerably smaller than 3.2 in FIG. 10A, so it can be determined that the teaching point is not good.

  As described above, according to the third embodiment, the teaching point evaluation result can be scored, and the teaching work time for returning to the teaching accuracy equivalent to the previous teaching time can be shortened.

  In addition, since the inspection result of each operation can be scored in the assembly operation process, the quality of the product completed by the assembly operation can be evaluated. For example, for the fitting operation of the part having the claw portion described in the first embodiment, the claw portion for preventing the disengagement is very important. Is small, it can be determined that the quality of the product assembled this time is not good.

Embodiment 4 FIG.
Next, the inspection apparatus 100 according to the fourth embodiment will be described. Below, it demonstrates focusing on a different point from Embodiment 1. FIG.

  In the first embodiment, the coordinate axis to be inspected is designated by one axis, but in the fourth embodiment, the number of means used in the inspection process and the coordinate axes to be inspected are set in plural.

  For example, the inspection means number 5 specifies a plurality of coordinate axes to be inspected by dividing them into a main target axis and a sub target axis, and selects an inspection means number to be used for each coordinate axis to be inspected.

  Alternatively, for example, the following command is executed and specified in the robot program describing the operation of the robot 1.

FsTALGo, main target axis inspection means number, main target axis, sub target axis inspection means number, sub target axis, eg FsTALGo, 51, 6, 52, 3
"51" is the number of the inspection means to be used, and "6" designates the C axis as the main target axis that is the execution target (inspection target) of the inspection means "51". “52” is the inspection means number used for the sub target axis, and “3” specifies that the axis that is the execution target (inspection target) of the inspection means “52” is the Z axis.

In the present embodiment, the sub target axis is designated as one axis, but may be designated as a plurality of axes according to work. For example, in a robot program, FsTALGo, 51, 6, 52, 3, 53, 1
May be described.

  As described above, according to the fourth embodiment, even if it is not possible to determine the success / failure of the work by inspecting the force information of one axis, it is possible to cope with determining the success / failure of the work by inspecting the force information of a plurality of axes. . For example, in the case of the inspection of the screw tightening operation, it is possible to determine the success or failure of the operation more accurately by simultaneously inspecting the force and moment in the direction of tightening the screw.

Embodiment 5 FIG.
Next, an inspection apparatus 100 according to the fifth embodiment will be described. Below, it demonstrates focusing on a different point from Embodiment 1. FIG.

  The physical meaning of the point designation in the inspection range designation means 8 is different from that in the first embodiment.

  In the first embodiment, the point is specified, but the total time from the beginning to the end of the force / position data is set as 100%, and the point is specified as a percentage. However, if the speed changes during the assembly operation, the force waveform changes, so that the inspection range specified by the inspection range specifying means 8 may not match the fitting operation.

  On the other hand, in the fifth embodiment, the point is specified, but the total movement amount from the beginning to the end of the position data of the inspection axis designated by the inspection means number selection means 5 (movement amount between the position data of the designated axis) It is assumed that the absolute value) is 100% and is specified as a percentage.

  The top of the position data of the coordinate axis to be inspected is 0% and the last is 100%. According to the fifth embodiment, it is possible to cope with a case where the speed is changed during the assembling work or a case where it is desired to perform an inspection including a reversing operation, so that an erroneous determination can be prevented.

  Further, in order to detect whether or not there is an abnormality during the assembly operation, the inspection end position and the inspection end position fluctuation range may be specified by the inspection range specifying means 8.

  For example, the following command is executed and specified in the robot program describing the operation of the robot 1.

      FsTBat, 70, 100, 3, 126.5, 0.3

  Here, “FsTBat” is a robot language (command) for designating the inspection process start rate and the inspection process end rate, and “3” is the value of which coordinate axis of the position data detected by the robot 1 is used. (For example, use the Z-axis value). “70, 100” designates that the inspection process starts at 70% of the total movement absolute amount from the beginning to the end of the Z-axis position data detected by the robot 1 and ends by 100%. “, 126.5,0.3” determines whether the work is completed by the end depending on whether or not the last value of the detected Z-axis position data is in the range of 126.5 ± 0.3. Is specified. “126.5” is the Z-axis position data of a point that is 100% of the total movement absolute amount from the beginning to the end of the Z-axis position data detected by the robot 1, and “0.3” is the workpiece displacement, This is a position variation amount corresponding to the work end position deviation.

  For example, as shown in FIG. 11, the horizontal axis of the graph is the ratio of the absolute position movement amount of the Z axis.

  In the embodiment, the inspection range is specified by the ratio of the total movement amount obtained by accumulating the movement amount absolute value between the specified axis position data. However, the total movement amount absolute value between the specified axis position data is accumulated. It may be specified by the amount of movement.

  As described above, according to the fifth embodiment, there is an effect that the inspection can be performed even when the speed is changed during the assembling work or when it is desired to perform the inspection including the reversing operation.

Embodiment 6 FIG.
Next, the inspection apparatus 100 according to the sixth embodiment will be described. Below, it demonstrates focusing on a different point from Embodiment 1. FIG.

  The contents displayed by the display means 11 are different from those in the first embodiment. As shown in FIGS. 11 (a) and 11 (b), the display means 11 simultaneously displays data with different vertical axes in two vertical screens. The horizontal axis is the same for both graphs. Data that can be selected as data to be used on the horizontal axis of the graph is, for example, X, Y, Z, A, B, and C. As shown in FIGS. 11A and 11B, one of them can be selected. As an alternative, the “ratio of absolute position movement amount” may be selected. The data that can be selected as data to be displayed on the vertical axis of the graph is, for example, X, Y, Z, A, B, C. One of them is “position” or “inspection axial force”. Alternatively, as shown in FIGS. 11A and 11B, a plurality of selections can be made.

  For example, as shown in FIGS. 11A and 11B, the horizontal axis of the graph is the ratio of the absolute position movement amount of the Z axis, and the vertical axis of the graph shown in FIG. 11B is the force detection of the Z axis. It is an output (inspection axial force), and the vertical axis of the graph shown in FIG. 11A is the position output detected by the Z axis. Per1 and Per2 are the start ratio and end ratio of the Z-axis absolute position movement amount of the inspection range specified by the inspection range specifying means 8. Zper1 is the Z-axis current position of the robot 1 when the ratio of the Z-axis absolute position movement amount is Per1, and Zper2 is the Z-axis current position of the robot 1 when the ratio of the Z-axis absolute position movement amount is Per2. is there.

  As described above, in the sixth embodiment, when the point designation in the inspection range designation unit 8 is the ratio of the absolute position movement amount of the axis, the force detection value and the position detection value are displayed at the same time. Since it becomes easy to grasp the actual work position where the work feature point is generated, there is an effect that the inspection apparatus is easy to use.

  As described above, the inspection apparatus according to the present invention is useful for inspection of parts assembly work.

M storage means 1 robot 2 force acquisition means 3 position acquisition means 4 acquisition condition specification means 5 inspection means number selection means 6 inspection means 7 inspection parameter specification means 8 inspection range specification means 9 cutout means 10 inspection output means 11 display means 61 extreme value Recognizing means 62 Judging means 100, 200, 300 Inspection device 220 Input means 320 Pointing means

Claims (6)

An inspection device for inspecting whether the assembly work of a part by a robot has succeeded or failed,
Force acquisition means for acquiring force acting on the robot tip;
Position acquisition means for acquiring the position of the robot tip;
Cutting means for cutting out a partial waveform of the inspection range from a waveform indicating the relationship between the acquired force and the acquired position;
Inspection range specifying means for specifying an inspection range to be cut out by the cutout means;
Extreme value recognition means for recognizing a plurality of extreme values in the partial waveform cut out by the cutting means;
A determination unit that selects a maximum value and a minimum value to be inspected according to a selection criterion from among the plurality of recognized extreme values, and determines whether a difference between the maximum value and the minimum value satisfies a determination criterion. When,
Inspection parameter designation means for designating selection criteria and judgment criteria to be used for the judgment means;
In accordance with the determination result by the determination unit, a test output unit that outputs a signal indicating success or failure of the work,
An inspection apparatus comprising: Input means for receiving an instruction for changing the inspection range to be specified by the inspection range specifying means or for changing at least one of the selection criterion and the determination criterion to be specified by the inspection parameter specifying means The inspection apparatus according to claim 1, wherein the inspection apparatus is provided. The inspection apparatus according to claim 1, further comprising an evaluation unit configured to evaluate a teaching point for the robot based on a difference between the maximum value and the minimum value and the determination criterion. The system further comprises: a plurality of coordinate axes to be inspected divided into a main target axis and a sub target axis, and a plurality of means for selecting an inspection means number to be used for each coordinate axis to be inspected. The inspection apparatus according to 1. The inspection range specifying means specifies the inspection range to be cut out by the cutout means as a ratio to the total movement amount from the beginning to the end of the position data of the coordinate axis to be inspected. The inspection device described. An inspection method for inspecting whether the assembly work of a part by a robot has succeeded or failed,
A designation step for designating an inspection range to be cut out from a waveform indicating the relationship between the force acting on the robot tip and the position of the robot tip;
A cut-out step of cutting out a partial waveform of the inspection range specified in the specifying step from the waveform;
An extreme value recognition step for recognizing a plurality of extreme values in the partial waveform cut out in the cutout step;
A selection step of selecting a maximum value and a minimum value to be inspected according to a selection criterion from a plurality of extreme values recognized in the extreme value recognition step;
A determination step for determining whether a difference between the maximum value and the minimum value selected in the selection step satisfies a determination criterion;
According to the determination result in the determination step, a test output step for outputting a signal indicating success or failure of the work,
An inspection method characterized by comprising:

Images