Device for measuring the amount of wear of a welding tip, control device, robotic system, method and computer program

Abstract

In the past, there has been a demand to adjust the time required for a measurement operation in which a welding tip is moved to a prescribed measurement position in order to measure a wear amount. The device (80) includes a measurement operation execution unit (70) that controls a moving machine (58) to execute a measurement operation in which the welding tip is moved to a measurement position in a first direction, a position data acquisition unit (72) that acquires the position of the moving machine (58) at a time after the measurement operation is executed, and a measurement start position determination unit (74) that determines the position of the moving machine (58) in which the welding tip is disposed at a prescribed distance away in a second direction opposite to the first direction with respect to a first position acquired in the first measurement operation as a measurement start position. The measurement operation execution unit (70) controls the moving machine (58) to move the welding tip in the first direction after the moving machine (58) is positioned at the measurement start position in a second measurement operation after the first measurement operation.

Description

Technical Field

[0001] This disclosure relates to an apparatus, control device, robot system, method, and computer program for measuring the wear of a welding tip. Background Technology

[0002] A device for measuring the wear of a welding nozzle is known (e.g., Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2007-268538 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] Previously, a measurement action was performed to move the welding nozzle to a specified measurement position in order to measure the amount of wear. However, there was a requirement to adjust the time required for this measurement action.

[0008] Solution for solving the problem

[0009] In one aspect of this disclosure, an apparatus for measuring the wear amount of a welding nozzle moved by a moving mechanism includes: a measurement action execution unit that controls the moving mechanism to perform a measurement action of moving the welding nozzle in a first direction to a predetermined measurement position for measuring the wear amount; a position data acquisition unit that acquires the position of the moving mechanism after the measurement action execution unit performs the measurement action; and a measurement start position determination unit that, based on the first position acquired by the position data acquisition unit in the first measurement action, determines the position of the moving mechanism, in which the welding nozzle is positioned at a predetermined distance away from the first direction in a second direction opposite to the first direction, as the measurement start position. In a second measurement action following the first measurement action, the measurement action execution unit controls the moving mechanism to move the welding nozzle in the first direction after positioning the moving mechanism to the measurement start position.

[0010] In another aspect of this disclosure, there is a method for measuring the wear of a welding nozzle moved by a moving mechanism, in which a processor performs the following processes: controlling the moving mechanism to perform a measurement action to move the welding nozzle in a first direction to a predetermined measurement position for measuring the wear; acquiring the position of the moving mechanism after the measurement action is performed; determining the position of the moving mechanism, in which the welding nozzle is positioned opposite to the first direction relative to the first position, as a measurement start position based on the first position acquired in the first measurement action; and in a second measurement action following the first measurement action, controlling the moving mechanism to move the welding nozzle in the first direction after positioning the moving mechanism to the measurement start position.

[0011] The effects of the invention

[0012] According to this disclosure, the starting point of the action that moves the welding nozzle during the measurement operation can be appropriately set. As a result, the time required for the measurement operation can be appropriately adjusted. Attached Figure Description

[0013] Figure 1 This is a diagram of a robot system involved in one implementation method.

[0014] Figure 2 yes Figure 1 The diagram shows a block diagram of the robot system.

[0015] Figure 3 yes Figure 1 An enlarged view of the welding torch shown.

[0016] Figure 4 Show Figure 1 The robot system shown includes a fixture for measuring wear.

[0017] Figure 5 This is a flowchart illustrating a method for measuring wear.

[0018] Figure 6 It is shown Figure 5 Step S1 and Figure 17 The flowchart is an example of step S41 in the process.

[0019] Figure 7 Showing the end Figure 6 The state at step S11.

[0020] Figure 8 Shown in Figure 6 The state when it is determined to be "yes" in step S13.

[0021] Figure 9 It is a diagram used to illustrate the starting position of the measurement.

[0022] Figure 10 This is a flowchart illustrating a method for measuring wear.

[0023] Figure 11 It is shown Figure 10 The flowchart is an example of step S21 in the process.

[0024] Figure 12 This is a diagram of a robot system involved in other implementations.

[0025] Figure 13 yes Figure 12 The diagram shows a block diagram of the robot system.

[0026] Figure 14 Shown in Figure 12 End of robot system shown Figure 6 The state at step S11.

[0027] Figure 15 Shown in Figure 12 In the robot system shown Figure 6 The state when it is determined to be "yes" in step S13.

[0028] Figure 16 It is used for explanation Figure 12 A diagram showing the measurement start position in the robot system.

[0029] Figure 17 This is a flowchart illustrating other examples of methods for measuring wear.

[0030] Figure 18 Shown in Figure 6 The state when it is determined to be "yes" in step S13.

[0031] Figure 19 It is used for explanation Figure 12 A diagram showing the measurement start position in the robot system.

[0032] Figure 20 It is shown Figure 17 The flowchart is an example of step S44 in the process. Detailed Implementation

[0033] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. Furthermore, in the various embodiments described below, the same reference numerals will be used to refer to the same elements, and repeated descriptions will be omitted. First, refer to... Figures 1-3 The following describes a robot system 10 according to one embodiment. The robot system 10 includes a robot 12, a welding torch 14, a control device 16, and a teaching pendant 18.

[0034] In this embodiment, robot 12 is a vertical articulated robot, having a robot base 20, a rotating body 22, a lower arm 24, an upper arm 26, and a wrist 28. The robot base 20 is fixed to the floor of the work area. The rotating body 22 is mounted on the robot base 20 in a manner that allows it to rotate about a vertical axis.

[0035] The lower arm portion 24 is rotatably mounted on the rotating body 22. The upper arm portion 26 is rotatably mounted on the front end of the lower arm portion 24. The wrist portion 28 has a wrist base 28a rotatably mounted on the front end of the upper arm portion 26, and a wrist flange 28b rotatably mounted on the wrist base 28a about a wrist axis A1.

[0036] Multiple servo motors 30 ( Figure 2 The servo motors 30 are respectively built into the robot base 20, rotating body 22, lower arm 24, upper arm 26, and wrist 28. These servo motors 30 rotate the various movable elements of the robot 12 (i.e., rotating body 22, lower arm 24, upper arm 26, wrist 28, and wrist flange 28b) according to instructions from the control device 16, thereby moving the welding torch 14.

[0037] The welding torch 14 is detachably mounted on the wrist flange 28b. For example... Figure 3 As shown, in this embodiment, the welding torch 14 is a so-called C-type spot welding torch, having a base portion 32, a fixed arm 34, a welding nozzle moving mechanism 36, a fixed welding nozzle 38, and a movable welding nozzle 40. The base portion 32 is connected to the wrist flange 28b via a support member 42. The fixed arm 34 has its base end 34a fixed to the base portion 32, and extends in an L-shape from the base end 34a to the front end 34b.

[0038] The nozzle moving mechanism 36, according to instructions from the control device 16, causes the movable nozzle 40 to reciprocate along the gun axis A2. Specifically, the nozzle moving mechanism 36 includes a movable arm 44, a servo motor 46, and a motion conversion mechanism 48. The movable arm 44 is provided on the base portion 32 in a manner that allows it to move along the gun axis A2. In this embodiment, the movable arm 44 is a rod-shaped member that extends linearly along the gun axis A2.

[0039] The servo motor 46 is fixed to the base 32. The motion conversion mechanism 48 includes, for example, a ball screw mechanism or a mechanism consisting of a timing belt and pulleys, which converts the rotational motion of the output shaft (not shown) of the servo motor 46 into the reciprocating motion of the movable arm 44 along the gun shaft A2. The fixed welding nozzle 38 is fixed to the front end 34b of the fixed arm 34, while the movable welding nozzle 40 is fixed to the front end 44a of the movable arm 44. The fixed welding nozzle 38 and the movable welding nozzle 40 are arranged in a manner that allows them to be aligned on the gun shaft A2.

[0040] During welding of the workpiece, the welding nozzle moving mechanism 36 drives the servo motor 46 to rotate according to the command from the control device 16, thereby moving the movable welding nozzle 40 along the gun shaft A2 toward the fixed welding nozzle 38 to clamp the workpiece between the movable welding nozzle 40 and the fixed welding nozzle 38. Next, the fixed welding nozzle 38 and the movable welding nozzle 40 are energized according to the command from the control device 16, thereby performing spot welding on the workpiece clamped between the fixed welding nozzle 38 and the movable welding nozzle 40.

[0041] The control device 16 controls the movements of the robot 12 and the welding torch 14. For example... Figure 2 As shown, the control device 16 is a computer having a processor 50, a memory 52, and an I / O interface 54. The processor 50 may have a CPU or GPU, etc. The processor 50 is communicatively connected to the memory 52 and the I / O interface 54 via a bus 56, thereby communicating with these components and performing calculations for the wear measurement function described later.

[0042] The memory 52 includes RAM or ROM, etc., for temporarily or permanently storing various data used in the computational processing performed by the processor 50, as well as various data generated during the computational processing. The I / O interface 54 has, for example, an Ethernet port, a USB port, a fiber optic connector, or an HDMI terminal, and communicates with external devices via wired or wireless means based on instructions from the processor 50. In this embodiment, the servo motor 30, servo motor 46, and teaching pendant 18 are connected to the I / O interface 54 in a communicative manner.

[0043] like Figure 1 As shown, a robot coordinate system C1 is established for robot 12. Robot coordinate system C1 is a coordinate system used for automatically controlling the various movable elements of robot 12. In this embodiment, robot coordinate system C1 is established for robot 12 with its origin located at the center of robot base 20 and its z-axis aligned with the rotation axis of rotating body 22. Furthermore, in the following description, for convenience, the positive direction of the z-axis of robot coordinate system C1 will be referred to as upward.

[0044] On the other hand, such as Figure 3As shown, a tool coordinate system C2 is set for the welding torch 14. The tool coordinate system C2 is a control coordinate system used to automatically control the position of the welding torch 14 within the robot coordinate system C1. Furthermore, in this document, "position" sometimes refers to both location and orientation. In this embodiment, the tool coordinate system C2 is set for the welding torch 14 with its origin located on the fixed welding nozzle 38 (e.g., the center of the front end face) and its z-axis aligned with (or parallel to) the torch axis A2. The positional relationship between the tool coordinate system C2 and the wrist flange 28b of the robot 12 is known based on information such as the dimensions of the welding torch 14.

[0045] When the welding torch 14 is moved, the processor 50 sets a tool coordinate system C2 in the robot coordinate system C1, sends commands to each servo motor 30 of the robot 12 and causes each movable element of the robot 12 to move, thereby positioning the welding torch 14 to the position represented by the set tool coordinate system C2. In this way, the processor 50 can position the welding torch 14 to any position in the robot coordinate system C1 through the movement of the robot 12.

[0046] Additionally, the processor 50 sends commands to the servo motor 46 of the nozzle moving mechanism 36, causing the movable arm 44 (i.e., the movable nozzle 40) to move along the gun axis A2 via the movement of the nozzle moving mechanism 36. Thus, in this embodiment, the movable nozzle 40 moves via the actions of the robot 12 and the nozzle moving mechanism 36. Therefore, the robot 12 and the nozzle moving mechanism 36 constitute a moving mechanism 58 that moves the movable nozzle 40.

[0047] like Figure 1 As shown, the teaching device 18 is a portable computer such as a teaching pendant or a tablet terminal device, and has a display unit 60 (LCD, organic EL display, etc.), an operation unit 62 (press button, touch sensor, etc.), a processor, and a memory (none of which are shown).

[0048] The operator can visually confirm the image displayed on the display unit 60 and operate the operation unit 62 to make the mobile machine 58 perform a slow movement. The operator can teach the mobile machine 58 a prescribed action by using the teaching device 18 to make the mobile machine 58 perform a slow movement, thereby creating an action program for making the mobile machine 58 perform the prescribed action.

[0049] Before (or after) welding operations using the welding torch 14, the movable welding nozzle 40 (and the fixed welding nozzle 38) are sometimes ground using a grinder. Due to this grinding operation, the movable welding nozzle 40 wears down. The processor 50 measures the amount of wear W of this movable welding nozzle 40. The method for measuring the amount of wear W is described below.

[0050] In this embodiment, using Figure 4The fixture 64 shown is used to measure the wear amount W. The fixture 64 is fixed at a predetermined position in the robot coordinate system C1. Specifically, the fixture 64 has a column 66 extending in the vertical direction and an abutment plate 68 extending horizontally from the upper end of the column 66. The abutment plate 68 has an upper surface 68a and a lower surface 68b arranged substantially parallel to the xy plane (i.e., the horizontal plane) of the robot coordinate system C1.

[0051] First, processor 50 executes... Figure 5 The process is shown below. It begins when the processor 50 receives the initial measurement start command CM1 from the operator, the higher-level controller, or the action program PG. Figure 5 The process is illustrated. The initial measurement start command CM1 is sent, for example, when a new, unworn movable welding nozzle 40 is installed on the movable arm 44. In step S1, the processor 50 executes the first measurement action MO1. (Refer to...) Figure 6 Let's explain step S1.

[0052] After step S1 begins, in step S11, processor 50 performs a first approach action to position the mobile mechanism 58 to a predetermined teaching position TP. Specifically, processor 50 positions the welding torch 14 to the first teaching position TP1 by moving the welding torch 14 via robot 12, and positions the movable arm 44 to the second teaching position TP2 by moving the movable arm 44 at a speed V1 via welding nozzle moving mechanism 36. Thus, in this embodiment, the teaching position TP of the mobile mechanism 58 includes the first teaching position TP1 to which robot 12 should position the welding torch 14 and the second teaching position TP2 to which welding nozzle moving mechanism 36 should position the movable arm 44.

[0053] exist Figure 7 The diagram shows the positional relationship between the welding torch 14 and the stationary object 64 when the mobile machine 58 is positioned in the teaching position TP. At this time, the abutment plate 68 of the stationary object 64 is positioned between the fixed welding nozzle 38 and the movable welding nozzle 40, with the movable welding nozzle 40 being positioned upwards at a predetermined distance relative to the upper surface 68a of the abutment plate 68.

[0054] Furthermore, the fixed welding nozzle 38 is positioned downwards at a predetermined distance relative to the lower surface 68b of the abutment plate 68, and the gun shaft A2 is approximately orthogonal to the upper surface 68a of the abutment plate 68. Additionally, when the moving machine 58 is positioned to the teaching position TP, the fixed welding nozzle 38 can also abut against the lower surface 68b without contact force.

[0055] The first teaching position TP1 of robot 12 is determined to be the representation Figure 7The position data (specifically, coordinates) of the tool coordinate system C2 (specifically, the origin position and the direction of each axis) are shown. Additionally, the second teach position TP2 of the welding nozzle movement mechanism 36 is determined as the rotational position (or rotation angle) of the servo motor 46.

[0056] For example, the operator can also teach the robot 12 to position the welding torch 14 by operating the teaching pendant 18 to perform slow movements. Figure 7 The actions at the indicated positions are performed to obtain the position data of the first teaching position TP1. The position data of the teaching positions TP (first teaching position TP1, second teaching position TP2) are pre-stored in the memory 52.

[0057] Refer again Figure 6 In step S12, the processor 50 moves the movable welding nozzle 40 toward the measurement position MP in a first direction. In this embodiment, the measurement position MP is the position of the upper surface 68a of the abutment plate 68. The processor 50 actuates the welding nozzle moving mechanism 36 to move the movable arm 44 forward at a speed V2 from the second teaching position TP2, thereby moving the movable welding nozzle 40 downward (in the first direction) at a speed V2. Here, this speed V2 is set to a value smaller than the speed V1 described above (V2). <V1)。

[0058] In step S13, the processor 50 determines whether the movable welding nozzle 40 has reached the measurement position MP. Specifically, the processor 50 determines whether the load torque τ of the servo motor 46 exceeds a predetermined threshold τ. th After step S12 begins, the front end of the movable welding nozzle 40 abuts against the upper surface 68a of the abutment plate 68, thereby positioning the movable welding nozzle 40 at the measurement position MP (that is, the position of the upper surface 68a).

[0059] exist Figure 8 The diagram shows the state in which the movable welding nozzle 40 is positioned at the measurement position MP. When the tip of the movable welding nozzle 40 abuts against the upper surface 68a, the load torque τ applied to the servo motor 46 increases. Therefore, by monitoring the load torque τ, it is possible to determine whether the movable welding nozzle 40 has reached the measurement position MP (in other words, whether it has abutted against the upper surface 68a).

[0060] As an example, the processor 50 can also obtain the feedback current from the servo motor 46 as the load torque τ. As another example, the welding torch 14 may also have a torque sensor that detects the torque applied to the output shaft of the servo motor 46, and the processor 50 may obtain the detection value of the torque sensor as the load torque τ.

[0061] In step S13, when the load torque τ exceeds the threshold τ thIn the case of (τ≥τ) th The processor 50 determines that the movable welding nozzle 40 has reached the measurement position MP (i.e., "yes"), and proceeds to step S14. On the other hand, when τ < τ th In the case of "no", processor 50 determines "no" and repeats step S13.

[0062] In step S14, the processor 50 stops the movable welding nozzle 40 by stopping the servo motor 46. Then, the processor 50 ends step S1 and proceeds to... Figure 5 Step S2. Through this step S1, the movable welding nozzle 40 is statically positioned at the measurement position MP (upper surface 68a).

[0063] As described above, in this embodiment, in the first measurement action MO1, the processor 50 controls the moving mechanism 58 to position the moving mechanism 58 to the teaching position TP in step S11, and then moves the movable welding nozzle 40 downward via the welding nozzle moving mechanism 36 in step S12. Therefore, the processor 50 acts as a measurement action execution unit 70 that controls the moving mechanism 58 to perform the measurement action MO. Figure 2 To fulfill its function.

[0064] Refer again Figure 5 In step S2, the processor 50 acquires the position P1 of the moving mechanism 58. Specifically, the processor 50 acquires the rotational position (or rotational angle) of the servo motor 46 at the end of step S1 as position data representing the position P1 of the movable arm 44 of the moving mechanism 58. As an example, the welding torch 14 may also have a rotation detector (encoder or Hall element, etc.) that detects the rotational position of the servo motor 46, and the processor 50 acquires the detection value of the rotation detector as the position P1.

[0065] As another example, the welding torch 14 may also have a position detector (linear scale or displacement sensor, etc.) that detects the position of the movable arm 44 in the direction of the torch axis A2, and the processor 50 acquires the detection value of the position detector as the position P1. Thus, in this embodiment, the processor 50 serves as the position data acquisition unit 72 for acquiring the position P1 of the moving mechanism 58. Figure 2 To fulfill its function.

[0066] In step S3, the processor 50 determines the measurement start position SP1 based on the position P1 obtained in step S2. (Refer to...) Figure 9 To illustrate the measurement start position SP1. Figure 9In the diagram, the movable arm 44 configured to position P1 via step S1 is shown by dashed line 44', and the movable welding nozzle 40 (i.e., measurement position MP) when the movable arm 44 is configured to position P1 is shown by dashed line 40'.

[0067] On the other hand, Figure 9 In the diagram, the movable arm 44, which will be configured to the measurement start position SP1, and the movable welding nozzle 40 when the movable arm 44 is configured to the measurement start position SP1, are shown in solid lines. Figure 9 As shown, when the movable arm 44 is positioned at the measurement start position SP1, the movable welding nozzle 40 is positioned upwards at a predetermined distance δ relative to when the movable arm 44 is positioned at position P1. On the other hand, when the movable arm 44 is positioned at the second teaching position TP2... Figure 7 In this case, the movable welding nozzle 40 is positioned downwards and away from the ground.

[0068] Based on the position P1 obtained in step S2, the processor 50 determines the measurement start position SP1 as the position of the movable arm 44 that is upwardly offset from the movable welding nozzle 40 by a distance δ relative to when the movable arm 44 is configured to position P1. For example, this distance δ is determined based on the positioning error α of the moving mechanism 58 in positioning the movable welding nozzle 40. The positioning error α refers to the distance by which the movable welding nozzle 40 may deviate from the target position when the moving mechanism 58 positions the movable welding nozzle 40 to the specified target position, and can be represented by a numerical range of ±α (e.g., α = 0.1 [mm]).

[0069] For example, the processor 50 determines the distance δ to be a value consistent with the positioning error α (δ = α), and determines the measurement start position SP1 of the movable arm 44 to be a position that moves upward from position P1 away from the distance δ = α. Alternatively, the processor 50 may also determine the distance δ to be the value obtained by multiplying the positioning error α by a predetermined coefficient κ (δ = κα). In this way, in this embodiment, the processor 50 serves as the measurement start position determination unit 74 that determines the measurement start position SP. Figure 2 To fulfill its function.

[0070] In execution Figure 5 After the process, the processor 50 repeatedly performs the following series of operations: moving the welding nozzles 38 and 40 by moving the moving mechanism 58 to spot weld the welding parts on the workpiece (not shown) through the welding nozzles 38 and 40, and then grinding the welding nozzles 40 (and welding nozzles 38).

[0071] In this series of operations, processor 50 executes the following whenever a grinding operation is performed: Figure 10 The process is shown below. It begins when the processor 50 receives the measurement start command CM2 from the operator, the higher-level controller, or the action program PG. Figure 10 the flow shown. The measurement start command CM2 can be sent every time the welding tips 38, 40 are ground.

[0072] In step S21, the processor 50 functions as a measurement operation executing unit 70 and executes the n-th measurement operation MO n (n=2, 3, 4, ...). With reference to Figure 11 , this step S21 will be described. In addition, in Figure 11 the flow shown, the same step numbers are assigned to the same processes as those in the flow shown in Figure 6 , and repeated descriptions are omitted.

[0073] After step S21 starts, the processor 50 executes the aforementioned step S11 to position the moving mechanism 58 at Figure 7 the teaching position TP shown. In step S31, the processor 50 executes a second approaching operation. Specifically, the processor 50 causes the welding tip moving mechanism 36 to operate, so that the movable arm 44 moves from the second teaching position TP2 at a speed V3 to the most recently determined measurement start position SP n-1 .

[0074] For example, when Figure 5 the flow shown is executed after the flow shown in Figure 10 , the number "n" for determining the n-th measurement operation MO n is n=2, and the most recently determined measurement start position SP n-1 is the aforementioned measurement start position SP1. Therefore, in this step S31, the processor 50 causes the movable arm 44 to move from the second teaching position TP2 to the measurement start position SP1. In addition, the speed V3 at which the movable arm 44 is moved in this step S31 may be set to the same value as the aforementioned speed V1, or may be set to a value different from speed V1. Furthermore, speed V3 may also be set to a value larger than the aforementioned speed V2.

[0075] In step S32, the processor 50 causes the movable welding tip 40 to move toward the measurement position MP in a first direction. Specifically, the processor 50 causes the welding tip moving mechanism 36 to operate, so that the movable arm 44 advances from the measurement start position SP n-1 at a speed V4, thereby moving the movable welding tip 40 downward at the speed V4. The speed V4 is set to a value smaller than the aforementioned speed V1 and speed V3 (V4<V1, V4<V3). In addition, speed V4 may also be set to the same value as the aforementioned speed V2.

[0076] In this way, in step S32, the processor 50 controls the moving mechanism 58 (the nozzle moving mechanism 36) to position the moving mechanism 58 (the movable arm 44) at the measurement start position SP n-1 and then moves the movable welding nozzle 40 downward. After step S32, the processor 50 executes the aforementioned steps S13 and S14 in sequence.

[0077] As described above, by executing steps S11, S31, S32 and S13, the processor 50 causes the movable arm 44 (that is, the movable welding nozzle 40) to move from the second teaching position TP2 ( Figure 7 ) to the measurement start position SP along the gun axis A2 at the speed V3 n-1 (for example, Figure 9 the position shown by the solid line 40), and then causes the movable arm 44 to move from the measurement start position SP n-1 to the measurement position MP at a speed V4 (<V3) ( Figure 8 the position shown).

[0078] Referring again to Figure 10 , in step S22, the processor 50 functions as the position data acquisition unit 72, and acquires the position P of the moving mechanism 58 (specifically, the movable arm 44) at the end of step S21 in the same manner as the aforementioned step S2 n (specifically, the rotational position of the servo motor 46).

[0079] In step S23, the processor 50 functions as the measurement start position determining unit 74 to determine the measurement start position SP n . Specifically, the processor 50, based on the position P acquired in the most recent step S22 n determines the measurement start position SP in the same manner as the aforementioned step S3 n as the position which, relative to the position P when the movable arm 44 is arranged at this position P n , the movable welding nozzle 40 is upwardly spaced apart by a distance δ, and relative to when the movable arm 44 is arranged at the second teaching position TP2 ( Figure 7 ), the movable welding nozzle 40 is downwardly spaced apart (refer to Figure 9 ).

[0080] In step S24, the processor 50 acquires the wear amount W. Specifically, the processor 50, based on the position P acquired when executing the (n-1)th measurement operation MO n-1 n-1 (the first position) and the position P acquired when executing the nth measurement operation MO n n (the second position), acquires the wear amount caused between the (n-1)th measurement operation MO n-1 ​​With the nth measurement action MO n The amount of wear W generated by the grinding operation performed between them n-1 .

[0081] For example, in Figure 5 The process shown will be executed afterward. Figure 10 In the process shown, n=2. Therefore, in step S24, the processor 50 obtains the wear amount W1 generated between the first measurement action MO1 and the second measurement action MO2 based on the position P1 obtained in step S2 above and the position P2 obtained in the most recent step S22.

[0082] As an example, processor 50 calculates the position P. n-1 The obtained rotational position RP of servo motor 46 n-1 With position P n The obtained rotational position RP of servo motor 46 n The difference Δ RP (=RP n -RP n-1 ), and the difference Δ RP The wear amount W is obtained by converting the displacement in the direction of the gun shaft A2. n-1 .

[0083] In this embodiment, the processor 50 acts as a location-based P... n-1 and position P n To obtain the wear amount W n-1 Wear measurement unit 76 ( Figure 2 The processor 50 then performs its function. Subsequently, in the series of welding and grinding operations, whenever the measurement start command CM2 is received (that is, whenever a grinding operation is performed), the processor 50 repeatedly executes the command. Figure 10 The process.

[0084] In addition, the processor 50 can also execute automatically according to the action program PG. Figure 5 and Figure 10 The process is shown. The action program PG contains instructions for causing the processor 50 to execute. Figure 5 and Figure 10 The computer program that provides various instructions for the process shown (e.g., instructions to servo motor 30 and servo motor 46).

[0085] The action program PG may also be provided in the form of a computer-readable recording medium (memory 52) such as a semiconductor memory, magnetic recording medium, or optical recording medium. The action program PG is created by an operator using the teaching pendant 18 and is pre-stored in the memory 52.

[0086] As described above, in this embodiment, the processor 50 functions as a measurement action execution unit 70, a position data acquisition unit 72, a measurement start position determination unit 74, and a wear amount acquisition unit 76 to measure the wear amount W. Therefore, the measurement action execution unit 70, the position data acquisition unit 72, the measurement start position determination unit 74, and the wear amount acquisition unit 76 constitute a device 80 for measuring the wear amount W. Figure 2 The device 80 (measuring action execution unit 70, position data acquisition unit 72, measurement start position determination unit 74, and wear amount acquisition unit 76) is a functional module implemented, for example, by a computer program (e.g., action program PG) executed by the processor 50.

[0087] In this embodiment, the processor 50 is based on the measurement action MO at the (n-1)th time. n-1 The position P obtained from n-1 (First position) to determine the measurement start position SP n-1 (Step S3 or S23) The nth measurement action MO n In the process of positioning the mobile machinery 58 (movable boom 44) to the measurement start position SP n-1 Then, the movable welding nozzle 40 is moved downward (in the first direction) (steps S31 and S32).

[0088] Like this, by determining the starting position SP for each measurement... n It can be appropriately set in the measurement action MO n The movement of the movable welding nozzle 40 at a speed of V4 is the starting point of the motion. As a result, the measurement motion MO can be appropriately adjusted. n The time required.

[0089] In addition, processor 50 will measure the start position SP. n-1 The decision is relative to position P. n-1 Regarding the position of the movable welding nozzle 40's moving mechanism 58, which is positioned upwards (in the second direction) away from the position by a distance δ. Based on this structure, the nth measurement action MO can be... n In the second approach action, the moving machine 58 was positioned at the measurement start position SP. n-1 At that time, the movable welding nozzle 40 moves upward from the measuring position MP (upper surface 68a) by a distance δ and a wear amount W. n-1 The sum of (δ+W) n-1 The distance is such that the movable welding nozzle 40 can be prevented from reaching the measuring position MP (i.e., abutting against the upper surface 68a) during the second approach action.

[0090] In addition, in this embodiment, the processor 50 measures the action MO. nThe movable welding nozzle 40 is moved downward until it abuts against the fixed object 64 (specifically, the upper surface 68a) positioned at the measurement position MP, thereby obtaining the position P of the moving mechanism 58 of the movable welding nozzle 40 when it abuts against the fixed object 64 at the measurement position MP. n .

[0091] According to this structure, by bringing the movable welding nozzle 40 abutting against the upper surface 68a, the moving mechanism 58 (movable arm 44) can be reliably stopped, and the reproducibility of the movement of the moving mechanism 58 bringing the movable welding nozzle 40 abutting against the stationary object 64 is also high. Therefore, the wear amount W can be obtained with high precision and stability. n .

[0092] Furthermore, in this embodiment, the processor 50 measures the nth action MO. n After positioning the mobile machine 58 to the teaching position TP (first approach action), the mobile machine 58 is then positioned to the measurement start position SP. n-1 (Second approach action). At this time, the processor 50 causes the moving mechanism 58 (movable arm 44) to move from the taught position TP to the measurement start position SP at a speed of V3 (first speed). n-1 Then, the movable mechanism 58 (movable boom 44) is moved from the measurement start position SP. n-1 It moves downward at a speed V4 (second speed) that is lower than speed V3 (step S32).

[0093] Here, in this embodiment, in step S13, it is determined whether the load torque τ of the servo motor 46 exceeds the threshold τ. th In step S14, the movable arm 44 is stopped. However, due to the delay in the torque response of the servo motor 46, the stopping position of the movable arm 44 in step S14 deviates.

[0094] To suppress such deviations and accurately measure the wear amount W, the speed at which the welding nozzle 40 reaches the measurement position MP during the measurement action MO needs to be set relatively low. Previously, whenever the measurement action MO was performed, after positioning the moving mechanism 58 to a pre-taught teaching position TP, the movable welding nozzle 40 was moved from that teaching position TP to the measurement position MP at a relatively low speed V4.

[0095] According to this embodiment, the movable welding nozzle 40 can be moved to the measurement start position SP at a relatively high speed V3 during the second approach action. n-1 Therefore, compared to the past, the measurement action MO can be shortened. n The required time. Therefore, it is possible to shorten the cycle time of the operation and improve the efficiency of the operation. On the other hand, by moving the movable welding nozzle 40 from the measurement start position SP... n-1The movable welding nozzle 40 moves to the measuring position MP at a relatively low speed V4, which can accurately obtain the position P of the moving mechanism 58 when it reaches the measuring position MP. n Therefore, it is possible to obtain the wear amount W with high precision. n .

[0096] In addition, in this embodiment, the processor 50 will measure the start position SP. n-1 The position of the movable welding nozzle 40 is determined as the position of the moving mechanism 58 (movable arm 44) that is downwardly opposite to the teaching position TP (second teaching position TP2). According to this structure, the movement of the movable welding nozzle 40 in steps S31 and S32 is a movement in the direction of a single axis (gun axis A2).

[0097] Therefore, steps S31 and S32 can be performed by the movement of the movable arm 44, which is movable in one axial direction, thus simplifying the measurement of motion MO. n The motion sequence PG and the structure of the moving mechanism 58. Additionally, the position P of the movable arm 44 on one axis. n The wear amount W can be detected with high precision by a rotary detector mounted on the servo motor 46. n .

[0098] Furthermore, in this embodiment, the measurement action MO is performed at the (n-1)th time. n-1 (For example, in the first measurement action MO1), after the moving mechanism 58 is positioned to the teaching position TP, the movable welding nozzle 40 is moved downward. Figure 6 or Figure 11 Step S11 in the process. According to this structure, in each measurement action MO n The common taught position TP is used in the first approach motion performed in the process, thus simplifying the measurement of motion MO. n PG (Programming Actions).

[0099] In addition, the processor 50 can also control the moving mechanism 58 (specifically, the welding nozzle moving mechanism 36) to complete the process. Figure 11 In step S31 (that is, when the movable arm 44 is configured to the measurement start position SP) n-1 After temporarily stopping the movable arm 44, in step S32 the movable arm 44 is moved downward.

[0100] In this case, the distance δ can also be determined based on the run-up distance β required for the welding nozzle moving mechanism 36 to accelerate the movable arm 44 from zero to the speed V4 in step S32. For example, the distance δ can be determined to be a value consistent with the run-up distance β (δ = β), or it can be determined to be a value obtained by multiplying the run-up distance β by a predetermined coefficient κ (δ = κβ). In this case, the processor 50 will measure the starting position SP in steps S3 and S23. n The decision is relative to position P. n As for the position that is upwards away from the distance δ (=β or κβ).

[0101] Alternatively, the processor 50 may continue executing step S32 without stopping the movable arm 44 after completing step S31. In this case, the processor 50 configures the movable arm 44 to the measurement start position SP in step S31. n-1 Then (or configure the movable boom 44 to the measurement start position SP) n-1 Previously, the speed V of the movable arm 44 was reduced from speed V3 to speed V4, and step S32 was executed.

[0102] In this case, the aforementioned distance δ can also be determined based on the run-up distance ε required for the welding nozzle moving mechanism 36 to decelerate the movable arm 44 from speed V3 to speed V4. For example, the distance δ can be determined as a value consistent with the run-up distance ε (δ=ε), or it can be determined as a value obtained by multiplying the run-up distance ε by a predetermined coefficient κ (δ=κε).

[0103] Next, refer to Figure 12 and Figure 13 The following describes a robot system 90 according to another embodiment. The robot system 90 differs from the robot system 10 described above in that it also includes an object detection sensor 92. The object detection sensor 92 is communicatively connected to the I / O interface 54 of the control device 16. The object detection sensor 92, for example, irradiates electromagnetic waves (infrared light, etc.) at the measurement position MP to detect objects passing through the measurement position MP in a non-contact manner. When an object is detected at the measurement position MP, the object detection sensor 92 sends an object detection signal to the control device 16.

[0104] As an example, the control device 16 (specifically, the processor 50) of the robot system 90 executes... Figure 5 and Figure 10 The process shown is used to measure the wear amount W. The following describes the process executed by the processor 50 of the robot system 90. Figure 5 and Figure 10 The process in the process is different from the process performed by the robot system 10 mentioned above.

[0105] exist Figure 6 or Figure 11 In step S11, the processor 50 of the robot system 90 executes a first approach action to position the mobile mechanism 58 to a predetermined taught position TP. Figure 14 The diagram shows the positional relationship between the welding torch 14 and the object detection sensor 92 when the mobile machine 58 is positioned at the teaching position TP in this embodiment.

[0106] exist Figure 14 In the example shown, the movable welding nozzle 40 is positioned upwards at a predetermined distance relative to the measurement position MP of the object detection sensor 92, and the nozzle axis A2 is approximately orthogonal to the measurement position MP (the direction of propagation of the electromagnetic wave emitted by the object detection sensor 92). The processor 50 positions the welding nozzle 14 at the location specified by the robot 12, which moves the welding nozzle 14. Figure 14 The tool coordinate system C2 shown represents the first teaching position TP1, and the movable arm 44 is moved at a speed V1 by the welding nozzle moving mechanism 36 so that the movable arm 44 is configured to the second teaching position TP2.

[0107] exist Figure 6 or Figure 11 In step S13, the processor 50 determines whether the movable welding nozzle 40 has reached the measurement position MP. Specifically, the processor 50 determines whether an object detection signal has been received from the object detection sensor 92 (the object detection signal is active). The result of the movable welding nozzle 40 moving downwards in step S12 or step S32 executed prior to step S13 is as follows: Figure 15 As shown, the movable welding nozzle 40 reaches the measurement position MP (that is, the propagation area of ​​the electromagnetic wave).

[0108] Therefore, the object detection sensor 92 sets the object detection signal to "on" and sends it to the control device 16. By monitoring the object detection signal, the processor 50 can determine whether the movable welding nozzle 40 has reached the measurement position MP. When the processor 50 receives the object detection signal from the object detection sensor 92, it determines "yes" and proceeds to step S14.

[0109] Then, in step S3 or step S23, as Figure 16 As shown, processor 50 is based on the most recently acquired position P n To measure the starting position SP n The decision is made so that the movable arm 44 is configured to this position P. n At time (position of dashed line 40'), the movable welding nozzle 40 is positioned upwards away from the movable arm 44 by a distance δ.

[0110] In this embodiment, the processor 50 measures the action MO.n The movable welding nozzle 40 is moved downward until the object detection sensor 92 detects the movable welding nozzle 40 at the measurement position MP. In step S2 or step S22, the position P of the moving mechanism 58 when the object detection sensor 92 receives the object detection signal is obtained. n According to this structure, compared to the case where the movable welding nozzle 40 abuts against the aforementioned fixed object 64, the load applied to the movable welding nozzle 40 and the welding nozzle moving mechanism 36 can be reduced.

[0111] Next, refer to Figure 17 To illustrate another example of the method for measuring wear W executed by the processor 50 of the robot system 90, the processor 50 of the robot system 90 repeatedly executes the above-mentioned measurement start command CM2 whenever it receives it. Figure 17 The process is shown below.

[0112] In step S41, the processor 50 functions as the measurement action execution unit 70 to execute the nth trial measurement action MO. T_n This step S41 and Figure 6 The process shown is the same. Specifically, in step S11, the processor 50 performs a first proximity action to position the moving machine 58 to the taught position TP. Figure 14 In step S12, the movable welding nozzle 40 is moved downward at a speed V1. Then, when the processor 50 determines "yes" in step S13 (that is, an object detection signal is received from the object detection sensor 92), the movable welding nozzle 40 is stopped in step S14.

[0113] In step S42, the processor 50 functions as the position data acquisition unit 72, acquiring the position P of the moving machine 58 at that time point in the same manner as in step S2 described above. T_n (The rotational position of servo motor 46) is used as the test measurement position P. T_n Here, due to the delay in the sensor response of the object detection sensor 92, the position of the movable arm 44 when the processor 50 receives the object detection signal is affected by the position of the movable arm 44 at the measurement position MP, which is a deviation from the speed V of the movable welding nozzle 40.

[0114] In other words, the accuracy of the object detection sensor 92 in detecting the movable welding nozzle 40 at the measurement position MP depends on the velocity V of the movable welding nozzle 40 after passing the measurement position MP. Figure 18 The image shows the position P of the movable welding nozzle 40 when the determination in step S13 is "yes" in step S41. T_n Examples.

[0115] In step S43, the processor 50 functions as the measurement start position determination unit 74, and similarly to step S3 above, it determines the measurement start position P based on the measurement position P obtained in step S42. T_n To determine the starting position of the formal measurement, SP R_n It was determined that the movable arm 44 was configured to the test measurement position P. T_n At that time, the movable welding nozzle 40 is positioned upwards at a distance δ relative to the movable arm 44, and is configured in the second teaching position TP2. Figure 14 At that time, the movable welding nozzle 40 is positioned downwards away from the movable arm 44.

[0116] exist Figure 19 The diagram shows the formal measurement start position SP determined in step S43. R_n Examples. In Figure 19 In step S41, the position P will be configured for the test measurement. T_n The movable arm 44 is shown as dashed line 44', and the movable arm 44 is configured to the test measurement position P. T_n The movable welding nozzle 40 is shown by dashed line 40'.

[0117] On the other hand, it will be configured to the formal measurement start position SP. R_n The movable boom 44, and the movable boom 44 are configured to the formal measurement start position SP. R_n The movable welding nozzle 40 is shown in solid lines. Here, the starting position SP is used to make the formal measurement begin. R_n The distance δ is determined by the upward-facing orientation of the front end of the movable welding nozzle 40 relative to the measurement position MP. For example, the distance δ can also be determined based on the positioning error α or the run-up distance β mentioned above.

[0118] Refer again Figure 17 In step S44, the processor 50 functions as the measurement action execution unit 70 to execute the nth formal measurement action MO. R_n . Reference Figure 20 To illustrate step S44. Furthermore, in Figure 20 In the process shown, for the relationship with Figure 11 The process flow shown uses the same process labels and figure references, and repeated descriptions are omitted.

[0119] After the processor 50 begins step S44, it performs a second approach action in step S31'. Here, in step S31', the processor 50 actuates the welding nozzle moving mechanism 36 to move the movable arm 44 from the position at the end of step S41 ( Figure 18 It moves at a speed of V3 to the formal measurement start position SP determined in the most recent step S43. R_n ( Figure 19 ).

[0120] In step S32', the processor 50 causes the movable welding tip 40 to move in a first direction toward the measurement position MP of the object detection sensor 92. Specifically, the processor 50 causes the welding tip moving mechanism 36 to operate, so that the movable arm 44 moves from the formal measurement start position SP R_n advances at a speed V4 (<V3), thereby causing the movable welding tip 40 to move downward at the speed V4. Thereafter, the processor 50 executes step S13 and step S14 sequentially.

[0121] As described above, the accuracy with which the object detection sensor 92 detects the movable welding tip 40 at the measurement position MP depends on the speed V. Therefore, by causing the movable welding tip 40 to move at the speed V4 which is lower than the speed V3 in step S32', it is possible to detect with high accuracy that the movable welding tip 40 has reached the measurement position MP.

[0122] Referring again to Figure 17 , in step S45, the processor 50 functions as a position data acquisition unit 72, and acquires the position P of the moving mechanism 58 (specifically, the movable arm 44) at the end of step S44 in the same manner as the above step S23 R_n (specifically, the rotation position of the servo motor 46) as the formal measurement position P R_n .

[0123] In step S46, the processor 50 functions as a wear amount acquisition unit 76 to acquire the wear amount W n-1 . Specifically, the processor 50 is based on the formal measurement position P acquired when the (n-1)th formal measurement operation MO R_n -1 is executed R_n-1 (third position) and the formal measurement position P acquired when the nth formal measurement operation MO R_n is executed R_n (second position), acquires the wear amount W generated by the grinding operation performed between the (n-1)th formal measurement operation MO R_n -1 and the nth formal measurement operation MO R_n n-1 .

[0124] In addition, when the processor 50 receives the above-mentioned initial measurement start command CM1 (that is, when an unworn new movable welding tip 40 is mounted on the movable arm 44), the processor 50 sequentially executes Figure 17 the flow of steps S41 to S45 therein, executes the first test measurement operation MO T_1 (step S41) and the first formal measurement operation MO R_1 (step S44), and acquires the formal measurement position P in step S45 R_1 . ​

[0125] As described above, in this embodiment, the processor 50 is based on the nth trial measurement action MO. T_n The test measurement position P obtained from the data T_n (First position) to determine the starting position of the formal measurement SP R_n (Step 43) In the nth formal measurement action MO R_n In the middle, the mobile machinery 58 (movable boom 44) is positioned at the formal measurement start position SP. R_n Then, the movable welding nozzle 40 is moved downwards (in the first direction). This is done by determining the test measurement position P each time. T_n The starting point of the action in step S44, which moves the movable welding nozzle 40 to the measurement position MP at a speed V4, can be appropriately set. As a result, the time required to measure the wear amount W can be appropriately adjusted.

[0126] In addition, in this embodiment, the processor 50 performs the test measurement action MO T_n The movable welding nozzle 40 moves at a relatively high speed V1, while the actual measurement action MO is being performed. R_n The movable welding nozzle 40 moves at a relatively low speed V4. This structure allows for more rapid acquisition of the test measurement position P. T_n On the other hand, it can obtain the formal measurement position P with higher precision. R_n .

[0127] Furthermore, in this embodiment, during the first approach action in step S41 and the second approach action in step S44, the movable welding nozzle 40 is moved at relatively high speeds V1 and V3, respectively. Based on this structure, the measurement action MO (specifically, the trial measurement action MO) can be shortened. T_n and formal measurement of motion MO R_n This reduces the time required for operations. Therefore, it can shorten the cycle time of operations and improve operational efficiency.

[0128] In addition, Figure 20 In step S44 shown, the processor 50 may also execute step S11 (first approach action) before step S31'. In this case, after step S44 begins, the processor 50 positions the moving mechanism 58 to the taught position TP in step S11. Figure 14 After that, in step S31', the movable arm 44 is moved from the teaching position TP (second teaching position TP2) to the formal measurement start position SP. R_n ( Figure 19 ).

[0129] In this case, the processor 50 can also complete step S31' (that is, when the movable arm 44 is configured to the formal measurement start position SP).R_n After temporarily stopping the movable arm 44 (at the time), in step S32', the movable arm 44 is moved downwards. Furthermore, the decision can also be based on the aforementioned run-up distance β. Figure 19 The distance δ (δ=β or δ=κβ).

[0130] Alternatively, the processor 50 may continue executing step S32' without stopping the movable arm 44 after completing step S31'. In this case, the decision can also be based on the aforementioned run-up distance ε. Figure 19 The distance δ (δ=ε or δ=κε).

[0131] Alternatively, it could be from Figure 10 Step S23 is omitted in the flowchart shown. The processor 50 is in Figure 11 In step S31, the mobile machinery 58 is positioned at... Figure 5 The measurement start position SP1 is initially determined in step S3. That is, in this case, in each measurement action MO n (n = 2, 3, 4, ...) uses a common measurement start position SP1.

[0132] Alternatively, you can also from Figure 11 Step S11 is omitted in step S21 shown. In this case, after step S21 begins, the processor 50 executes the second approach action of step S31, causing the moving mechanism 58 (movable arm 44) to move directly to the most recently determined measurement start position SP. n-1 At this time, the processor 50 can also move the movable mechanism 58 (movable arm 44) to the measurement start position SP at a speed of V1 or V3. n-1 .

[0133] In the above embodiment, it is described that the processor 50 obtains the rotational position of the servo motor 46 in steps S2, S22, S42, and S45 as the position P of the moving machine 58. n However, it is also possible that the processor 50 obtains, for example, the coordinates CD of the front end 44a of the movable arm 44 in the robot coordinate system C1 as the position P of the moving machine 58. n .

[0134] The coordinate system CD can be determined based on the position data of the tool coordinate system C2 in the robot coordinate system C1 and the rotational position of the servo motor 46. Furthermore, the position data of the tool coordinate system C2 after the measurement action is performed (that is, at the end of steps S1, S21, S41, and S44) can be determined based on the rotational position of each servo motor 30 of the robot 12.

[0135] In the above embodiment, it is described that in steps S12, S31, S32, S31', and S32', the processor 50 actuates the welding nozzle moving mechanism 36 to move the movable arm 44 downward. However, it is also possible that the processor 50 actuates the robot 12 in steps S12, S31, S32, S31', and S32' to move the welding torch 14 downward. In this case, the processor 50 may also obtain the coordinates CD mentioned above in steps S2, S22, S42, and S45 as the position P of the moving mechanism 58. n .

[0136] In the above embodiment, it is described that the processor 50 measures the start position SP in steps S3, S23, and S43. n SP R_n The position of the movable arm 44 is determined to be downwardly offset from the teaching position TP by the movable welding nozzle 40. That is, in this case, the measurement starts at position SP. n SP R_n The teaching position TP is arranged on the gun axis A2.

[0137] However, processor 50 can also measure the start position SP. n SP R_n The position of the movable arm 44 is determined, for example, by the movable welding nozzle 40 moving away from the left or right relative to the teaching position TP. That is, in this case, the measurement start position SP is determined. n SP R_n The teaching position TP is offset from the position TP in a direction intersecting the gun axis A2. The processor 50, by causing the robot 12 to move, enables the mobile mechanism 58 (i.e., the movable welding nozzle 40) from this teaching position TP to the measurement start position SP. n SP R_n .

[0138] In the above embodiments, the case of moving the movable welding nozzle 40 to measure the wear amount W is described. However, the processor 50 can also perform the action by causing the robot 12 to move. Figure 5 , Figure 10 or Figure 17 The procedure shown is used to measure the wear W of the fixed welding nozzle 38.

[0139] The wear measurement unit 76 can also be omitted from device 80. For example, it could be from... Figure 10 Step S24 is omitted in the process; the operator refers to the first position P. n-1 Second position P n Manually calculate the wear amount W. n-1 Alternatively, it could be from... Figure 17Step S46 is omitted in the process; the operator refers to the third position P. R_n-1 Second position P R_n Manually calculate the wear amount W. n-1 .

[0140] Alternatively, the function of the wear measurement unit 76 can be installed on an external device of the device 80 (e.g., an external server or a computer different from the control device 16). In this case, the processor 50 can also omit step S24 (or S46) and send the acquired first position P to the external device via a network (Internet or LAN, etc.). n-1 Second position P n (or third position P) R_n-1 Second position P R_n The wear amount W is obtained from this external device. n-1 .

[0141] Furthermore, in the above embodiment, the function of device 80 is described as being implemented in control device 16. However, the function of device 80 may also be implemented in teaching pendant 18, or it may be implemented in an external device (external server, PC, etc.) that is configured to communicate with control device 16. In this case, the processor of teaching pendant 18 or external device functions as device 80.

[0142] Furthermore, the robot 12 is not limited to a vertical multi-joint robot, but can also be any type of robot such as a horizontal multi-joint robot or a parallel robot. Additionally, in the above embodiment, the mobile mechanism 58 is described as having the robot 12 and the welding nozzle moving mechanism 36, but it is not limited to this; for example, the welding nozzle 38 or welding nozzle 40 can also be moved by multiple ball screw mechanisms.

[0143] Furthermore, the welding torch 14 is not limited to a C-type spot welding torch; for example, it could be an X-type spot welding torch, or any other type of welding torch. The present disclosure has been described above through embodiments, but the above embodiments are not intended to limit the invention as defined in the claims.

[0144] Explanation of reference numerals in the attached figures

[0145] 10, 90: Robot system; 12: Robot; 14: Welding torch; 16: Control device; 36: Welding nozzle moving mechanism; 38, 40: Welding nozzle; 58: Moving machinery; 70: Measurement action execution unit; 72: Position data acquisition unit; 74: Measurement start position determination unit; 76: Wear amount acquisition unit.

Claims

1. An apparatus for measuring the wear of a welding nozzle moved by a moving mechanism, the apparatus comprising: The measuring action execution unit controls the moving machinery to perform a measuring action that moves the welding nozzle in a first direction to a predetermined measuring position in order to measure the amount of wear; A position data acquisition unit acquires the position of the moving machine after the measurement action execution unit performs the measurement action; as well as The measurement start position determination unit determines the position of the moving mechanism, which is positioned at a predetermined distance away from the welding nozzle in a second direction opposite to the first direction, relative to the first position, based on the first position obtained by the position data acquisition unit during the first measurement operation. In the second measurement action following the first measurement action, the measurement action execution unit controls the moving mechanism to position the moving mechanism at the measurement start position after positioning it at a teaching position predetermined to cause the welding nozzle to move away from the second direction relative to the measurement start position, and then moves the welding nozzle in the first direction after positioning the moving mechanism at the measurement start position.

2. The apparatus according to claim 1, wherein, It also includes a wear amount acquisition unit, which acquires the wear amount generated between the first measurement action and the second measurement action based on the first position and the second position acquired by the position data acquisition unit in the second measurement action.

3. The apparatus according to claim 1, wherein, A fixed object or a sensor for detecting the welding nozzle is installed at the measurement location. The measuring action execution unit moves the welding nozzle in the first direction during the measuring action until the welding nozzle abuts against the fixed object at the measuring position, or the sensor detects the welding nozzle at the measuring position.

4. The apparatus according to claim 2, wherein, A fixed object or a sensor for detecting the welding nozzle is installed at the measurement location. The measuring action execution unit moves the welding nozzle in the first direction during the measuring action until the welding nozzle abuts against the fixed object at the measuring position, or the sensor detects the welding nozzle at the measuring position.

5. The apparatus according to claim 1, wherein, It also includes a wear amount acquisition unit, which acquires the wear amount generated between the third measurement action and the second measurement action based on the third position acquired by the position data acquisition unit in the third measurement action before the first measurement action and the second position acquired by the position data acquisition unit in the second measurement action.

6. The apparatus according to claim 5, wherein, A sensor for detecting the welding nozzle is installed at the measurement location. The measuring action execution unit moves the welding nozzle in the first direction during the measuring action until the sensor detects the welding nozzle at the measuring position.

7. The apparatus according to claim 1, wherein, The measurement start position determination unit determines the measurement start position as the position of the moving machine in the first direction, relative to the teaching position, where the welding nozzle is away from the moving machine.

8. The apparatus according to claim 1, wherein, The measurement action execution unit controls the moving mechanism during the first measurement action to move the welding nozzle in the first direction after positioning the moving mechanism to the teaching position.

9. The apparatus according to claim 7, wherein, The measurement action execution unit controls the moving mechanism during the first measurement action to move the welding nozzle in the first direction after positioning the moving mechanism to the teaching position.

10. The apparatus according to any one of claims 1 to 9, wherein, In the second measurement action, the measurement action execution unit causes the moving machine to move to the measurement start position at a first speed, and causes the moving machine to move in the first direction from the measurement start position at a second speed lower than the first speed.

11. A control device comprising the means according to any one of claims 1 to 10, the control device performing an operation of moving the welding nozzle by the moving mechanism and welding a workpiece using the welding nozzle.

12. A robot system comprising: Mobile machinery, used to move the welding nozzle; and The control device according to claim 11 is used to control the mobile machinery.

13. A method for measuring the amount of wear on a welding nozzle moved by a moving mechanism, wherein a processor performs the following processes: The moving machinery is controlled to perform a measurement action that moves the welding nozzle in a first direction to a predetermined measurement position in order to measure the amount of wear; Obtain the position of the moving machine after the measurement action is performed; Based on the first position obtained in the first measurement action, the position of the moving machine that is configured to move away from the welding nozzle in a second direction opposite to the first direction relative to the first position is determined as the measurement start position; as well as In the second measurement action following the first measurement action, the moving mechanism is controlled to be positioned at the measurement start position after the moving mechanism is positioned at a teaching position predetermined to cause the welding nozzle to move away from the second direction relative to the measurement start position, and after the moving mechanism is positioned at the measurement start position, the welding nozzle is moved in the first direction.

14. A computer program product comprising a computer program that causes the method of claim 13 to be executed in the processor.

Images