Device, control device and method for correcting pressure command of welding gun

Abstract

In an operation for acquiring a pressurizing force in order to correct a pressurizing force command of a welding gun, a technique for optimizing the number of postures for positioning the welding gun and simplifying the operation is required. A device (70) is provided with: an operation execution unit (62) that operates a robot (12) so as to position a welding gun (14) in a teaching posture prescribed in a welding work program; a pressing force acquisition unit (64) that acquires a pressing force when the welding gun (14) is driven by the first pressing force command when the operation execution unit (62) positions the welding gun (14) in the teaching posture; and a command correction unit (66) that corrects the first pressing force command on the basis of the pressing force acquired by the pressing force acquisition unit (64), thereby obtaining a second pressing force command when the welding gun (14) is driven in the teaching posture when the welding work program is executed.

Description

Technical Field

[0001] The present disclosure relates to a device, a control device, and a method for correcting a pressure command for specifying a pressure of a welding gun. Background Art

[0002] There is known a device that corrects a pressure command that specifies the pressure of a welding gun according to the posture of the welding gun (for example, Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2001-47249 Summary of the invention

[0006] Problems to be solved by the invention

[0007] Conventionally, there has been a demand for a technique for correcting a pressure command with high accuracy and simplifying the work involved in the correction.

[0008] Means for solving problems

[0009] One embodiment of the present disclosure is a device that corrects a pressure command based on a posture of a welding gun, the pressure command defining a pressure of the welding gun when a robot moves and pressurizes a workpiece to perform welding, the device comprising: an action execution unit that causes the robot to perform an action so as to position the welding gun to a teaching posture defined by a welding operation program that causes the robot and the welding gun to perform a welding operation; a pressure acquisition unit that acquires a pressure when the welding gun is driven with a first pressure command when the action execution unit positions the welding gun to the teaching posture; and a command correction unit that corrects the first pressure command based on the pressure obtained by the pressure acquisition unit, thereby obtaining a second pressure command when the welding gun is driven in the teaching posture when the welding operation program is executed.

[0010] Another aspect of the present disclosure is a method for correcting a pressure instruction according to a posture of a welding gun, the pressure instruction specifying the pressure of the welding gun when a robot moves and pressurizes a workpiece to perform welding, in which a processor performs the following processing: causing the robot to move so as to position the welding gun to a teaching posture specified by a welding operation program that causes the robot and the welding gun to perform a welding operation; obtaining a pressure when the welding gun is driven by a first pressure instruction when the welding gun is positioned to the teaching posture; and correcting the first pressure instruction according to the obtained pressure, thereby obtaining a second pressure instruction when the welding gun is driven in the teaching posture when the welding operation program is executed.

[0011] Effects of the Invention

[0012] According to the present disclosure, by correcting the pressure command using the teaching posture for positioning the welding gun in the actual welding operation, a second pressure command that can cause the welding gun to generate a fixed pressure regardless of the posture can be obtained with high accuracy. In addition, since there is no need to re-teach the robot the posture for correcting the pressure command, the operation of correcting the pressure command can be simplified. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of a welding robot system according to one embodiment.

[0014] Figure 2 yes Figure 1 Block diagram of the welding robot system shown.

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

[0016] Figure 4 Indicates Figure 3 The welding gun posture changes as shown.

[0017] Figure 5 Yes means Figure 1 Flowchart of an example of a method for correcting a pressure command executed by a welding robot system shown.

[0018] Figure 6 This shows an example of a welding procedure.

[0019] Figure 7 This shows an example of a position data table.

[0020] Figure 8 An example of a data table showing welding conditions.

[0021] Fig. 9 This is an enlarged view showing a welding gun according to another embodiment.

[0022] Fig.10 This is a schematic diagram of a welding robot system according to another embodiment.

[0023] Fig.11 yes Fig.10 Block diagram of the welding robot system shown.

[0024] Fig.12 Yes means Fig.10 Flowchart of an example of a method for correcting a pressure command executed by a welding robot system shown.

[0025] Fig.13 Yes means Fig.11 Block diagram of other functions of the welding robot system shown.

[0026] Fig.14 Yes means Fig.13 Flowchart of an example of a method for correcting a pressure command executed by a welding robot system shown.

[0027] Fig.15 Yes means Figure 2 Block diagram of other functions of the welding robot system shown.

[0028] Fig.16 Yes means Fig.15 Flowchart of an example of a method for correcting a pressure command executed by a welding robot system shown.

[0029] Fig.17 Yes means Fig.16 A flowchart of an example of the process of step S35 in .

[0030] Fig.18 This shows another example of the position data table.

[0031] Fig.19 This shows an example of a posture reproduction program.

[0032] Fig. 20 This shows another example of the position data table.

[0033] Fig.21 Yes means Fig.11 A block diagram of yet another function of the welding robot system shown.

[0034] Fig. 22 Yes means Fig.21 Flowchart of an example of a method for correcting a pressure command executed by a welding robot system shown.

[0035] Fig.23 Yes means Fig. 22 A flowchart of an example of the process of step S54 in .

[0036] Fig.24 This shows another example of the position data table.

[0037] Fig.25 This section shows another example of a gesture reproduction program. DETAILED DESCRIPTION

[0038] Hereinafter, embodiments of the present disclosure will be described in detail based on the accompanying drawings. In the various embodiments described below, the same elements are denoted by the same reference numerals, and repeated descriptions are omitted. Figure 1 and Figure 2 Next, a welding robot system 10 according to an embodiment will be described. The welding robot system 10 includes a robot 12 , a welding gun 14 , a pressure sensor 16 , and a control device 18 .

[0039] In this embodiment, the robot 12 is a vertical articulated robot, and includes a robot base 20, a rotary 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 unit. The rotary body 22 is provided on the robot base 20 so as to be rotatable about a vertical axis.

[0040] The lower arm 24 is provided on the rotating body 22 so as to be rotatable around a horizontal axis. The upper arm 26 is provided on the front end of the lower arm 24 so as to be rotatable. The wrist 28 includes a wrist base 28a provided on the front end of the upper arm 26 so as to be rotatable, and a wrist flange 28b provided on the wrist base 28a so as to be rotatable around a wrist axis A1.

[0041] A plurality of servo motors 30 ( Figure 2 These servo motors 30 rotate the movable components of the robot 12 (i.e., the rotary body 22, the lower arm 24, the upper arm 26, the wrist 28, and the wrist flange 28b) according to the command from the control device 18, thereby moving the welding gun 14.

[0042] The welding gun 14 is detachably mounted on the wrist flange 28b. Figure 3 As shown, in this embodiment, the welding gun 14 is a so-called C-type spot welding gun, and includes a base 32 , a fixed arm 34 , a fixed welding tip 36 , a movable arm 38 , a servomotor 40 , a motion conversion mechanism 42 , and a movable welding tip 44 .

[0043] The base portion 32 is connected to the wrist flange 28b. The base end 34a of the fixed arm 34 is fixed to the base portion 32, and the fixed arm 34 is bent and extended from the base end 34a to the front end 34b in a substantially L-shape. The fixed welding tip 36 is fixed to the front end 34b of the fixed arm 34.

[0044] The movable arm 38 is provided on the base portion 32 so as to be reciprocatingly movable along the welding gun axis A2. In the present embodiment, the movable arm 38 is a rod-shaped member extending linearly along the welding gun axis A2. The movable welding tip 44 is fixed to the front end 38a of the movable arm 38 so as to be aligned with the fixed welding tip 36 on the welding gun axis A2. In addition, the welding gun axis A2 may be arranged parallel to the wrist axis A1.

[0045] The servo motor 40 has an output shaft (not shown) fixed to the base 32. The motion conversion mechanism 42 has, for example, a ball screw mechanism or a mechanism composed of a timing belt and a pulley, and converts the rotational motion of the output shaft of the servo motor 40 into reciprocating motion of the movable arm 38 along the welding gun axis A2.

[0046] The control device 18 controls the actions of the robot 12 and the welding gun 14. Figure 2 As shown, the control device 18 is a computer having a processor 50, a memory 52, and an I / O interface 54. The processor 50 has a CPU or a GPU, etc., and is communicatively connected to the memory 52 and the I / O interface 54 via a bus 56, communicates with these components, and performs arithmetic processing for a function of correcting a pressure command described later.

[0047] The memory 52 includes a RAM or a ROM, etc., and temporarily or permanently stores various data used in the operation processing executed by the processor 50 and various data generated in the middle of the operation processing. The I / O interface 54 includes, for example, an Ethernet (registered trademark) port, a USB port, an optical fiber connector, or an HDMI (registered trademark) terminal, and communicates data with external devices by wire or wirelessly under the instruction from the processor 50. In the present embodiment, the servo motors 30 and 40 and the pressure sensor 16 are connected to the I / O interface 54 in a wired or wireless manner so as to be communicable.

[0048] The control device 18 is further provided with an input device 58 and a display device 60. The input device 58 includes a keyboard, a mouse, a touch panel, etc., and receives data input from an operator. The display device 60 includes a liquid crystal display, an organic EL display, etc., and displays various data.

[0049] The input device 58 and the display device 60 are connected to the I / O interface 54 in a wired or wireless manner. In addition, the input device 58 and the display device 60 may be integrally assembled in the housing of the control device 18, or may be provided separately from the housing of the control device 18 as a computer (PC, etc.).

[0050] like Figure 1 As shown, a robot coordinate system C1 is set for the robot 12. The robot coordinate system C1 is a coordinate system for automatically controlling each movable component of the robot 12. In the present embodiment, the robot coordinate system C1 is set relative to the robot 12 in such a way that its origin is arranged at the center of the robot base 20 and its z-axis coincides with the rotation axis of the rotating body 22.

[0051] On the other hand, Figure 3 As shown, a tool coordinate system C2 is set for the welding gun 14. The tool coordinate system C2 is a coordinate system that specifies the position and posture of the welding gun 14 in the robot coordinate system C1. In the present embodiment, the tool coordinate system C2 is set relative to the welding gun 14 in such a way that its origin (so-called TCP) is arranged on the fixed welding tip 36 (for example, the center of the front end surface) and its z-axis is consistent with (or parallel to) the welding gun axis A2.

[0052] When the welding gun 14 is moved, the processor 50 first sets the tool coordinate system C2 in the robot coordinate system C1, and generates instructions (position instructions, speed instructions, torque instructions, etc.) for each servo motor 30 of the robot 12 to position the welding gun 14 at a position and posture represented by the set tool coordinate system C2. In this way, the welding gun 14 moves by the action of the robot 12 and is positioned at an arbitrary position and posture in the robot coordinate system C1.

[0053] The welding gun 14 applies pressure to a workpiece (not shown) to perform welding. Specifically, the processor 50 sends a pressure command F to the servo motor 40. C , the movable arm 38 is moved along the welding gun axis A2, thereby moving the movable welding nozzle 44 toward the fixed welding nozzle 36. As a result, the workpiece is clamped between the movable welding nozzle 44 and the fixed welding nozzle 36. At this time, the pressure command F is applied to the workpiece from the movable welding nozzle 44. C The corresponding pressure F.

[0054] Next, the processor 50 activates the fixed welding tip 36 and the movable welding tip 44, and energizes the fixed welding tip 36 and the movable welding tip 44. As a result, the workpiece clamped between the fixed welding tip 36 and the movable welding tip 44 is welded. The pressure command F sent to the servo motor 40 C It is a command for defining the pressure F to be generated by the welding gun 14 and indicates a target value of the pressure F (for example, 2 [kN]).

[0055] The pressure sensor 16 has a piezoelectric element or a strain gauge, etc., and measures the pressure F of the welding gun 14. Specifically, the pressure sensor 16 is configured to be held by an operator with one hand, and is manually set by the operator between the fixed welding tip 36 and the movable welding tip 44 when measuring the pressure F. The pressure sensor 16 is clamped between the movable welding tip 44 driven by the servo motor 40 and the fixed welding tip 36, and measures the pressure F applied to the pressure sensor 16 at this time. The pressure sensor 16 provides the detection data of the measured pressure F to the control device 18.

[0056] Here, the predetermined pressure command F C When the welding gun 14 is driven, the pressure F generated by the welding gun 14 can be changed according to the posture of the welding gun 14. Figure 3 In the example shown, the welding gun 14 is arranged in a posture OR0 in which the welding gun axis A2 is parallel to the vertical direction and the movable welding tip 44 is arranged vertically above the fixed welding tip 36 .

[0057] In such a posture OR0, it is assumed that the processor 50 commands F C_0 (For example, F C_0 =1 [kN]) drives the servo motor 40, and the welding gun 14 follows the pressure command FC_0 The movable welding tip 44 pressurizes the object to be pressurized (for example, the fixed welding tip 36 ).

[0058] At this time, the pressure F0 applied from the movable welding tip 44 to the object to be pressed becomes the force component F in the direction of the welding gun axis A2 converted by the motion conversion mechanism 42 into the torque of the servo motor 40. τ The gravitational force component F of the movable part of the welding gun 14 composed of the motion conversion mechanism 42, the movable arm 38 and the movable welding nozzle 44 is g The resultant force F0 (=F τ +F g ).

[0059] Then, from Figure 3 The posture OR0 shown in FIG. 1 is such that the welding gun 14 is rotated by an angle θ about the y-axis of the tool coordinate system C2 and is arranged Figure 4 The posture shown is OR θ In the state, the processor 50 sends the same pressure instruction F C_0 The servo motor 40 is driven to pressurize the object to be pressurized by the movable welding nozzle 44. At this time, the pressure F applied to the object to be pressurized from the movable welding nozzle 44 is θ The force component F τ With the gravity component F g The force component F obtained by multiplying by cosθ g The net force F of cosθ θ (=F τ +F g cosθ).

[0060] Therefore, the posture OR θ Pressure F θ and Figure 3 Compared with the pressure F0 in the posture OR0 shown in the figure, the pressure F g (1-cosθ) In this way, the pressure F changes according to the posture OR of the welding gun 14. Such a change in the pressure F corresponding to the posture OR affects the welding quality.

[0061] Therefore, in the present embodiment, the processor 50 corrects the pressure command F according to the posture OR of the welding gun 14. C . Below, refer to Figure 5 Correction pressure command F C The method is described below. Figure 5 The illustrated flow starts when the processor 50 receives a calibration start instruction from an operator or a host controller or the like.

[0062] In step S1, the processor 50 obtains the welding operation program 200. The welding operation program 200 is a computer program for causing the robot 12 and the welding gun 14 to perform welding operations. Figure 6 An example of a welding work procedure 200 is schematically shown.

[0063] exist Figure 6 In the welding operation program 200 shown, for example, the code "MOVE [TP1] VELOCITY [V1]" in the first line is a positioning command IN for moving the welding gun 14 at a speed V = V1 [mm / sec] by the robot 12 and positioning it at the first teaching position TP1 and teaching posture OR1 indicated by the identifier [TP1]. P .

[0064] On the other hand, as data different from the welding work program 200 , a position data table 202 is prepared in advance and stored in the memory 52 . Figure 7 An example of the position data table 202 is schematically shown. Figure 7 In the position data table 202 shown, coordinate data to which identifiers “TP1”, “TP2”, “TP3”, and “TP4” are respectively assigned are stored.

[0065] For example, the identifier "TP1" is assigned to the coordinates (X1, Y1, Z1, W1, P1, R1). Among the coordinates (X1, Y1, Z1, W1, P1, R1), (X1, Y1, Z1) are coordinates of the robot coordinate system C1 where the welding gun 14 (specifically, TCP) is to be positioned, indicating the first teaching position TP1. On the other hand, (W1, P1, R1) are coordinates of the respective axis directions (so-called yaw, pitch, and roll) of the tool coordinate system C1 in the robot coordinate system C1, indicating the first teaching posture OR1.

[0066] When the processor 50 executes the welding operation program 200, it reads the positioning command IN of the first line "MOVE[TP1]VELOCITY[V1]" P When TP1 is reached, the position data table 202 is referred to, and the coordinates (X1, Y1, Z1, W1, P1, R1) indicated by the identifier “TP1” are obtained from the position data table 202.

[0067] Then, the processor 50 sets the origin position represented by the coordinates (X1, Y1, Z1, W1, P1, R1) and the tool coordinate system C2 of each axis direction in the robot coordinate system C1, and generates instructions (position instructions, speed instructions, torque instructions, etc.) to each servo motor 30 of the robot 12, so that the welding gun 14 moves at a speed V1 to the first teaching position TP1 and the teaching posture OR1 represented by the set tool coordinate system C2. In this way, the processor 50 follows the positioning command IN P By operating the robot 12 , the welding gun 14 is positioned at the first teaching position TP1 and the teaching posture OR1 .

[0068] Thus, in this embodiment, the n-th teaching position TP is defined in the welding operation program 200. n And teaching posture OR n (n=1, 2, 3, 4) nth teaching position TP n And teaching posture OR n The robot 12 is taught in advance by an operator using a teaching device (teaching pendant, tablet terminal device, etc.).

[0069] In addition, in each positioning command IN P In the code "MOVE[TPn]VELOCITY[Vn]" (n=1, 2, 3, 4), the speed V can also be recorded in the code "[Vn]" that specifies the speed V. n Alternatively, the maximum speed V at which the robot 12 moves the welding gun 14 may be recorded in "[Vn]". MAX The percentage [%] of (e.g., "80%").

[0070] Alternatively, similar to the above-mentioned position data table 202, a table for storing the speed V n The speed data table stored together with the identifier "Vn" is different from the welding program 200. In this case, the processor 50 reads the positioning command IN of "MOVE[TPn]VELOCITY[Vn]" in the 2i-1th line (i=1, 2, 3, 4). P When the speed data table is referred to, the speed V assigned with the identifier "Vn" is obtained from the speed data table. n In addition, the speed V specified in the welding operation program 200 n : "VELOCITY[Vn]" can be different speeds, or at least two (for example, all) speeds V n same.

[0071] Refer again Figure 6 In the welding operation program 200, the code "GUN [ON] CONDITION [1]" in the 2ith line (i = 1, 2, 3, 4) is a welding command IN for starting the welding gun 14 to weld the workpiece according to the welding condition 1 assigned with the identifier [1]. W .

[0072] Here, a plurality of workpieces having various thicknesses and materials can be welded. In the present embodiment, a plurality of mutually different welding conditions m (m=1, 2, 3, ...) are set in advance for each type of workpiece. Figure 8 An example of welding condition 1 to which identifier [1] is assigned is shown.

[0073] In welding condition 1, parameters such as pressure F1 = 2 [kN], welding current I1 = 8 [kA], and welding time t1 = 10 [sec] are set. Figure 8 The data table of welding conditions m shown as an example (pressure F m , welding current I m , welding time t m ) are prepared in advance according to the type of workpiece (i.e., thickness, material), and stored in the memory 52. ​​In addition, in the welding condition m, the pressure F may also be set. m , welding current I m And welding time t m Any parameters other than welding voltage (e.g. welding voltage, etc.)

[0074] When the processor 50 executes the welding operation program 200, if the welding command IN such as "GUN [ON] CONDITION [1]" in the 2ith line is read, W , the data table of welding condition 1 assigned with identifier [1] is referred to, and parameters of welding condition 1 such as pressure F1=2 [kN], welding current I1=8 [kA], and welding time t1=10 [sec] are obtained.

[0075] Then, the processor 50 generates a pressure command F corresponding to the pressure F1 specified in the welding condition 1. C_1 (=2[kN]), according to the pressure command F C_1 The servo motor 40 that drives the welding gun 14 clamps the workpiece between the movable welding tip 44 and the fixed welding tip 36 .

[0076] Meanwhile, the servo motor 40 of the welding gun 14 is provided with a load detection sensor LS (not shown) for detecting load torque or feedback current of the servo motor 40. The processor 50 obtains feedback FB1 (ie, load torque or feedback current) from the load detection sensor LS.

[0077] Here, a pressure command F is executed in advance to set the pressure command F to the servo motor 40. C According to the pressure command F C The calibration operation is performed to make the pressure F generated by the driven welding gun 14 consistent with each other. This calibration operation is performed, for example, when the welding gun 14 is arranged in a predetermined reference posture OR0 by the robot 12. The reference posture OR0 is, for example, Figure 3 Pose shown.

[0078] In this calibration operation, the operator installs a pressure sensor 16 between the movable welding tip 44 and the fixed welding tip 36 of the welding gun 14 arranged in the reference posture OR0, and measures the pressure according to the pressure command F by the pressure sensor 16.C The pressure F when the welding gun 14 is driven. The operator obtains the correlation between the feedback FB1 from the load detection sensor LS and the measured pressure F at this time, and corrects the correlation so that the pressure command F C It is consistent with the applied pressure F.

[0079] The processor 50 follows the welding command IN W With pressure command F C_1 During the driving of the servo motor 40, a feedback FB1 is obtained from the load detection sensor LS, and the feedback FB1 becomes C_1 When the corresponding value is reached, the servo motor 40 is stopped.

[0080] Next, the processor 50 energizes the fixed welding tip 36 and the movable welding tip 44 according to the welding current I1 (=8 [kA]) specified by the welding condition 1, and welds the workpiece within the welding time t1 (=10 [sec]). W , welding operation is performed on the workpiece.

[0081] In step S1, the processor 50 obtains the positioning command IN as described above. P And welding command IN W For example, the welding operation program 200 is pre-stored in the memory 52 , and the processor 50 obtains the welding operation program 200 by reading the welding operation program 200 from the memory 52 .

[0082] Alternatively, the welding operation program 200 may be stored in another computer (host controller, production management server, teaching device, etc.). The other computer can be communicatively connected to the I / O interface 54 of the control device 18 via a communication network (Internet, LAN). The processor 50 may also obtain the welding operation program 200 by downloading it from the other computer.

[0083] In step S2, the processor 50 executes the positioning command IN of the welding operation program 200. P In this embodiment, the processor 50 reads the positioning command IN such as "MOVE[TP1]VELOCITY[V1]" specified in the first line of the welding operation program 200 in step S2. P The robot 12 moves the welding gun 14 at a speed V1 to position the welding gun 14 at the first teaching position TP1 and the teaching posture OR1. n The action execution unit 62 ( Figure 2 ) to perform its function.

[0084] In step S3, the processor 50 determines whether the welding gun 14 is positioned at the nth teaching position TP. n And teaching posture OR n Specifically, the processor 50 can determine whether to position the welding gun 14 to the nth teaching position TP based on the feedback FB2 (for example, the position feedback, speed feedback or acceleration feedback of the servo motor 30) from the rotation detection sensor RS1 (encoder or Hall element, etc.) provided in each servo motor 30 of the robot 12. n and teaching posture OR n .

[0085] For example, when step S3 is executed after step S2, the processor 50 determines whether the welding gun 14 is positioned at the first teaching position TP1 and the teaching posture OR1. When the processor 50 determines that the welding gun 14 is positioned at the nth teaching position TP n And teaching posture OR n (ie, "Yes"), the operation of the robot 12 is stopped and the process proceeds to step S4. Thus, the welding gun 14 is positioned at the n-th teaching position TP. n And teaching posture OR n On the other hand, when the processor 50 determines that the result is "No", the processor 50 executes step S3 in a loop.

[0086] If the determination result in step S3 is "yes", the processor 50 reads the positioning command IN executed in step S2 (or the most recently executed step S8 described below) in the welding operation program 200. P The next line specifies the welding command IN W However, in Figure 5 In the process, the processor 50 does not execute the welding command IN W Instead, the pressure obtaining action FO is executed.

[0087] Here, in the present embodiment, in the control device 18, instead of the welding command IN W A flag FL for executing a pressure obtaining operation FO described later is set. When the flag FL is enabled, the processor 50 does not execute the welding command IN read out when the determination result is "YES" in step S3. W Instead, as the pressure obtaining operation FO, steps S4 to S7 described later are executed.

[0088] For example, the operator or the upper controller may send a flag setting signal to the control device 18, and the processor 50 may switch the flag FL to be valid or invalid according to the flag setting signal. Figure 5When the operator or the upper controller provides the control device 18 with a flag setting signal for making the flag FL effective, the processor 50 sets the flag FL to be effective according to the flag setting signal. Figure 5 When the judgment is "yes" in step S3, the welding command IN is replaced. W , execute steps S4 to S7 as the pressure obtaining action FO.

[0089] In step S4, the processor 50 determines whether a pressure acquisition operation start instruction is received from the operator. For example, the processor 50 generates an image or sound notification signal SG1 such as "Please install a pressure sensor between the movable welding tip and the fixed welding tip", and displays the notification signal SG1 as an image on the display device 60, or outputs it as a sound from a speaker (not shown) provided in the control device 18.

[0090] The operator manually sets the pressure sensor 16 between the movable welding tip 44 and the fixed welding tip 36, operates the input device 58, and provides the pressure acquisition operation start instruction to the processor 50. When the processor 50 receives the pressure acquisition operation start instruction, it determines that it is "yes" and enters step S5. On the other hand, when it determines that it is "no", it loops and executes step S4.

[0091] In step S5, the processor 50 performs the welding according to the pressure F specified in the welding condition m. m Corresponding pressure command F C_m (first pressure command) to drive the welding gun 14. Specifically, the processor 50 reads the welding command IN when the determination result in the most recent step S3 is "yes". W The processor 50 uses the code "CONDITION [1]" to obtain the pressure F1 (=2 [kN]) specified by the welding condition 1 assigned with the identifier [1]. Then, the processor 50 generates a pressure command F corresponding to the pressure F1 obtained from the welding condition 1. C_1 (=2[kN]), according to the pressure command F C_1 A servo motor 40 drives the welding gun 14 .

[0092] On the other hand, the processor 50 obtains feedback FB1 from the load detection sensor LS while driving the servo motor 40. When the feedback FB1 becomes equal to the pressure command F C_1 As a result, the pressure sensor 16 is sandwiched between the movable welding tip 44 and the fixed welding tip 36, and the pressure sensor 16 is applied with the pressure command F. C_1 The corresponding pressure F.

[0093] In step S6, the pressure F is obtained. Specifically, the processor 50 obtains the pressure F measured by the pressure sensor 16 at the end of step S5 (i.e., when the servo motor 40 is stopped) and stores it in the memory 52. C_1 The next pair is positioned at the nth teaching position TP in the most recent step S2 (or step S8 described later). n And teaching posture OR n The pressure F actually measured by the pressure sensor 16 when the welding gun 14 is driven.

[0094] Therefore, the processor 50 serves as a pressure obtaining unit 64 ( Figure 2 Even if the above calibration operation is performed, the pressure F obtained in step S6 will be adjusted according to the nth teaching posture OR for positioning the welding gun 14. n And the pressure command F C_1 (That is, the pressure F1=2 [kN] specified in welding condition 1) is different.

[0095] In step S7, the processor 50 determines whether all the teaching positions TP specified in the welding procedure 200 are n And teaching posture OR n The pressure F is obtained. If the processor 50 determines that it is "yes", the process ends. Figure 5 On the other hand, in the illustrated flow, when the determination is "NO", the process proceeds to step S8.

[0096] In step S8, the processor 50 executes the positioning command IN specified in the next line of the welding operation program 200. P For example, when executing step S8 for the first time, the processor 50 executes the positioning command IN of the third row. P “MOVE[TP2] VELOCITY[V2]” moves the welding gun 14 at a speed V2 in order to position the welding gun 14 at the second teaching position TP2 and the teaching posture OR2.

[0097] Then, the processor 50 returns to step S3. In this way, the processor 50 repeatedly executes the loop of steps S3 to S8 until a "yes" determination is made in step S7. Each time step S8 is executed and the welding gun 14 is positioned at the nth teaching position TP, n And teaching posture OR n When the pressure F is obtained in step S6.

[0098] In the End Figure 5After the process shown in the figure, the processor 50 executes the welding operation program 200 to perform the actual welding operation on the workpiece. When performing the actual welding operation, the operator or the upper controller provides the control device 18 with a flag setting signal for invalidating the flag FL, and the processor 50 sets the flag FL to invalid according to the flag setting signal. As a result, in the actual welding operation, the processor 50 executes the welding command IN of the welding operation program 200. W , welding operation is performed on the workpiece.

[0099] In the present embodiment, when the welding operation program 200 is executed for the actual welding operation, the processor 50 corrects the pressure command F based on the pressure F obtained in the above-mentioned step S6. C_1 For example, in the above step S2 or S8, the positioning command IN of the 2i-1th row is executed. P The welding gun 14 is positioned at the nth teaching position TP. n And teaching posture OR n The pressure F obtained in the subsequent step S6 is 1.5 [kN].

[0100] In this case, the processor 50 obtains the positioning command IN of the 2i-1th row to be executed in the actual welding operation. P The next welding command IN of line 2i W The pressure command F for the servo motor 40 for driving the welding gun 14 is C_1 =2 [kN]) is the correction amount ΔF, for example, the pressure F and the pressure command F C_1 The difference ΔF (=0.5[kN]).

[0101] Then, the processor 50 generates the pressure command F C_1 Add the correction amount ΔF to make correction and obtain the new pressure command F C_1 '=2.5[kN] (second pressure command). In addition, the correction amount ΔF is not limited to the pressure F and the pressure command F C_1 The difference between the pressure F and the pressure command F may be obtained by multiplying the difference by a predetermined coefficient, or by using the pressure F and the pressure command F. C_1 It can be found by any other arbitrary operation of .

[0102] Then, the processor 50 executes the welding command IN of line 2i. W When the pressure command F is corrected, C_1 '(=2.5 [kN]) to drive the servo motor 40. Thus, the welding machine can be positioned in the nth teaching posture OR in the actual welding operation. nThe pressure F applied to the workpiece by the welding gun 14 is substantially consistent with the pressure F1 specified in the welding condition 1.

[0103] Thus, in the present embodiment, the processor 50 corrects the first pressure command F based on the pressure F acquired in step S6. C_1 , thereby obtaining the teaching posture OR when executing the welding operation program 200 n The second pressure command F when driving the welding gun 14 C_1 'Instruction correction unit 66 ( Figure 2 ) to perform its function.

[0104] As described above, in this embodiment, the processor 50 functions as the operation execution unit 62, the pressure acquisition unit 64, and the command correction unit 66 to correct the pressure command F that specifies the pressure F of the welding gun 14 according to the posture OR of the welding gun 14. C Therefore, the operation execution unit 62, the pressure acquisition unit 64, and the command correction unit 66 constitute a system for correcting the pressure command F according to the posture OR of the welding gun 14. C Device 70( Figure 2 ).

[0105] In the device 70, the operation execution unit 62 positions the welding gun 14 to the teaching posture OR specified in the welding operation program 200. n The robot 12 is moved in the manner of (steps S2 and S8), and the pressure acquiring unit 64 acquires the position of the welding gun 14 in the teaching posture OR in the action executing unit 62. n When the first pressure command F C_1 The pressure F when the welding gun 14 is driven (step S6). Then, the command correction unit 66 corrects the first pressure command F based on the pressure F acquired by the pressure acquisition unit 64. C_1 , thereby determining the time required to perform the welding operation procedure 200 in the teaching posture OR n The second pressure command F when driving the welding gun 14 C_1 '.

[0106] According to this configuration, the welding gun 14 can be positioned based on the teaching posture OR in the actual welding operation. n The pressure F obtained under the correction pressure command F C_1 Thus, the second pressure command F can be obtained with high accuracy. C_1 ', the second pressure command F C_1 The welding gun 14 can generate a constant pressure F regardless of the position of the welding gun 14 in the actual welding operation. In addition, it is not necessary to re-teach the robot 12 for correcting the pressure instruction F. C_1 Therefore, the correction pressure command F can be simplified.C_1 homework.

[0107] In the device 70, the welding operation program 200 includes: operating the robot 12 to position the welding gun 14 to the nth teaching position TP n And teaching posture OR n Positioning command IN P and start the welding gun 14 and the welding command IN of the workpiece W Then, the action execution unit 62 executes the positioning command IN of the welding operation program 200. P , the robot 12 positions the welding gun 14 to the nth teaching position TP n And teaching posture OR n (Steps S2, S8), on the other hand, the welding command IN is not executed W (Steps S4 to S7).

[0108] Then, the pressure acquiring unit 64 acquires the information that the operation executing unit 62 positions the welding gun 14 to the nth teaching position TP. n And teaching posture OR n According to this structure, the robot 12 can perform the same action as the actual welding operation, and obtain the correction force instruction F. C_1 Therefore, at the welding site, the action of obtaining the pressure F can be performed while avoiding interference between the robot 12 and peripheral equipment.

[0109] In the device 70, the pressure obtaining unit 64 obtains the pressure at the first pressure command F. C_1 The drive is positioned by the motion execution unit 62 to the nth teaching posture OR n When the welding gun 14 is connected, the pressure F is measured by the pressure sensor 16. According to this structure, the pressure F can be actually measured with high accuracy by the pressure sensor 16, so the second pressure instruction F can be obtained with higher accuracy. C_1 '.

[0110] In the above-mentioned embodiment, the action program PG1 for executing the pressure acquisition operation FO (steps S4 to S7) may be prepared separately from the welding work program 200. In this case, when the processor 50 determines "yes" in step S3, it executes the action program PG1 and executes steps S4 to S7 as the pressure acquisition operation FO.

[0111] In the above-mentioned embodiment, the case where the flag FL is set in the control device 18 is described. However, the present invention is not limited to this. In the welding operation program 200 acquired in step S1, each welding command IN may be set. WThe code "GUN [ON] CONDITION [1]" is assigned a flag FL for executing the pressure obtaining operation FO instead. Then, the processor 50 refers to the welding command IN read out when the judgment is "YES" in step S3. W The mark FL is assigned instead of the welding command IN W , as the pressure obtaining operation FO, steps S4 to S7 are executed.

[0112] Furthermore, when the welding operation program 200 is executed to perform the actual welding operation, the flag FL may be deleted from the welding operation program 200. Alternatively, the processor 50 may delete the flag FL when executing the welding command IN of the welding operation program 200. W When the welding command IN is executed, the assigned flag FL is ignored. W .

[0113] In addition, in the above-mentioned embodiment, the pressure sensor 16 is connected to the I / O interface 54 of the control device 18, and the measured pressure F is provided to the control device 18. However, the present invention is not limited thereto, and the pressure sensor 16 may not be connected to the control device 18. In this case, the operator may operate the input device 58 to manually input the pressure F measured by the pressure sensor 16 at the end of the above-mentioned step S5 to the control device 18.

[0114] In the above embodiment, the welding robot system 10 is provided with the pressure sensor 16 independent of the welding gun 14, and the operator manually sets the pressure sensor 16. However, the pressure sensor 16 may be integrally assembled with the welding gun 14.

[0115] Fig. 9 Indicates this way. Fig. 9 In the welding robot system 10' shown, the pressure sensor 16' is fixedly installed integrally with the movable welding nozzle 44 on the movable arm 38. The pressure sensor 16' is configured to detect the force acting on the pressure sensor 16' as a reaction force when the movable welding nozzle 44 driven by the servo motor 40 pressurizes the object to be pressurized (for example, the fixed welding nozzle 36), thereby measuring the pressure F applied to the object to be pressurized.

[0116] According to the welding robot system 10 ', it is possible to Figure 5 Specifically, when the processor 50 determines that the result in step S3 is "yes", the processor 50 executes step S5 to press the pressure command F C_1The servo motor 40 of the welding gun 14 is driven. As a result, the movable welding tip 44 is pressed against the fixed welding tip 36 as the object to be pressurized, and the fixed welding tip 36 is pressurized. In addition, the processor 50 generates a feedback signal FB1 obtained from the load detection sensor LS and generates a pressure command F C_1 When the corresponding value is reached, the servo motor 40 is stopped.

[0117] In addition, when executing step S5, a pressurized object (iron plate, etc.) separated from the welding gun 14 may be inserted between the movable welding tip 44 and the fixed welding tip 36, and the pressurized object may be pressurized by the movable welding tip 44. Next, in step S6, the processor 50 obtains the pressurizing force F measured by the pressurizing force sensor 16' at this time. In addition, the pressurizing force sensor 16' may also be fixedly arranged between the fixed welding tip 36 and the fixed arm 34.

[0118] Next, refer to Fig.10 as well as Fig.11 Next, a welding robot system 80 according to another embodiment will be described. The welding robot system 80 is different from the welding robot system 10 described above in the following configurations. Specifically, the welding robot system 80 does not include the above-described pressure sensor 16 , while the welding gun 14 includes a position sensor 68 .

[0119] The position sensor 68 detects the position PS of the movable welding tip 44. As an example, the position sensor 68 includes a rotation detection sensor RS2 (encoder or Hall element, etc.) provided on the servo motor 40 of the welding gun 14, and detects the rotation position (or rotation angle) of the servo motor 40. The rotation position of the servo motor 40 is related to the position of the movable arm 38 and the movable welding tip 44 in the direction of the welding gun axis A2, so the position sensor 68 of this example can detect the position PS of the movable welding tip 44 by detecting the rotation position of the servo motor 40.

[0120] As another example, the position sensor 68 has a linear scale SC, which is provided on the welding gun 14 (for example, the base portion 32) and can directly detect the position PS of the movable arm 38 or the movable welding tip 44 in the direction of the welding gun axis A2. The position sensor 68 (rotation detection sensor RS2 or linear scale SC) provides detection data of the detected position PS to the control device 18.

[0121] Next, refer to Fig.12 , the pressure instruction F is corrected in the welding robot system 80 C In addition, Fig.12 In the process of Figure 5 The same steps in the flow chart are marked with the same step numbers and repeated descriptions are omitted. Fig.12After the process shown starts, the processor 50 executes step S1 to obtain the welding operation program 200 .

[0122] In this embodiment, the processor 50 analyzes the acquired welding operation program 200 and refers to the welding command IN of the 2ith line. W Then, the processor 50 retrieves the welding condition 1 data table ( Figure 8 ) obtains information on the pressure F1 (=2 [kN]) included in the welding condition 1 assigned the identifier [1] in the code.

[0123] After step S1, in step S11, the processor 50 positions the welding gun 14 to the reference posture OR0. Specifically, the processor 50 operates the robot 12 to position the welding gun 14 to the reference posture OR0. Figure 3 As a result, the welding gun axis A2 of the welding gun 14 is parallel to the vertical direction, and the movable welding tip 44 is arranged vertically above the fixed welding tip 36 .

[0124] In step S12, the processor 50 performs the welding according to the pressure F specified in the welding condition m. m Corresponding pressure command F C_m (First pressure command) drives the welding gun 14. Specifically, the processor 50 generates a pressure command F corresponding to the pressure F1 based on the information of the pressure F1 included in the welding condition 1 acquired in step S1. C_1 (=2[kN]), according to the pressure command F C_1 A servo motor 40 drives the welding gun 14 .

[0125] As a result, the movable welding tip 44 is pressed against the fixed welding tip 36 as the object to be pressed. Then, the processor 50 generates a signal when the feedback FB1 from the load detection sensor LS is equal to the pressure command F C_1 When the corresponding value is reached, the servomotor 40 is stopped. As a result, the pressure F1 is applied from the movable welding nozzle 44 to the pressure sensor 16 .

[0126] Here, through the above calibration operation, the pressure command F C The pressure F when driving the welding gun 14 arranged in the reference posture OR0 and the pressure instruction F C Therefore, in step S12, the pressure F applied to the pressure sensor 16 becomes equal to the pressure command F. C 1 The welding condition 1 has the same pressure F1 (=2 [kN]).

[0127] In step S13, the processor 50 obtains the first position PS1 of the movable nozzle 44. Specifically, the processor 50 obtains from the position sensor 68 the first position PS1 (or rotational position) detected by the position sensor 68 when step S12 ends (ie, when the servo motor 40 stops).

[0128] Thus, in this embodiment, the processor 50 functions as the position acquisition unit 72 ( Fig.11 ) plays a role, the position acquisition unit 72 acquires the first pressure command F C_1 The first position PS1 is detected by the position sensor 68 when the welding gun 14 positioned in the reference posture OR0 is driven to pressurize the object to be pressurized (specifically, the fixed tip 36 ) by the movable tip 44 .

[0129] After step S13, the processor 50 sequentially executes the above steps S2, S3 and S5. As a result, the n-th teaching position TP is positioned. n And teaching posture OR n The welding gun 14 follows the pressure instruction F C_1 (=2 [kN]) is driven, and the movable welding tip 44 pressurizes the fixed welding tip 36 as the object to be pressurized with the pressure F. The pressure F at this time is based on the n-th teaching posture OR n , may be related to the pressure command F C_1 (That is, the pressure F1 of welding condition 1 = 2 [kN]) is different.

[0130] In step S14, processor 50 functions as position acquisition unit 72 to acquire second position PS2 of movable nozzle 44. Specifically, processor 50 acquires second position PS2 (or rotational position) detected by position sensor 68 when step S5 ends (i.e., when servo motor 40 stops).

[0131] When executing step S14, the pressure F applied by the movable tip 44 to the fixed tip 36 may be different from the pressure F1 when executing step S13 as described above. Therefore, the second position PS2 obtained in step S14 may be different from the first position PS1 obtained in step S13.

[0132] Thus, the processor 50 functions as the position acquisition unit 72 to acquire the position of the first pressure command F. C_1 The drive is positioned to the nth teaching posture OR in step S2 or S8 n The second position PS2 is detected by the position sensor 68 when the welding gun 14 is used to pressurize the object to be pressurized (specifically, the fixed welding tip 36) with the movable welding tip 44.

[0133] In step S15, the processor 50 functions as the pressure obtaining unit 64 and obtains the pressure F. Here, there is a relationship shown in the following formula 1 among the first position PS1 obtained in step S13, the second position PS2 obtained in step S14, the pressure F1 specified by the welding condition 1 obtained in step S1, and the pressure F obtained in step S15.

[0134] PS1 / PS2=F1 / F…(Formula 1)

[0135] Through the above calibration operation, as described above, the pressure F1 in equation 1 and the pressure command F C_1 =2[kN] is known to be the same. Therefore, the pressure F can be obtained by calculation such as F=F1·PS2 / PS1 according to Formula 1. The processor 50 stores the obtained pressure F in the memory 52.

[0136] After step S15, the processor 50 sequentially executes the above-mentioned steps S7 and S8 until the determination result in step S7 is "yes", and repeatedly executes the loop of steps S3, S5, S14, S15, S7 and S8, and each time the welding gun 14 is positioned at the nth teaching position TP in step S8 n And teaching posture OR n When the pressure F is obtained in step S15.

[0137] In the End Fig.12 After the process shown in the figure, the processor 50 executes the welding operation program 200 for the actual welding operation, similarly to the above-mentioned embodiment. During the execution of the welding operation program 200, the processor 50 functions as the instruction correction unit 66 to correct each teaching posture OR based on the pressure F obtained in step S15. n The pressure command F C_1 , and thus the pressure command F is obtained C_1 '.

[0138] As described above, in this embodiment, the processor 50 functions as the operation execution unit 62, the pressure acquisition unit 64, the command correction unit 66, and the position acquisition unit 72, thereby correcting the pressure command F according to the posture OR of the welding gun 14. C Therefore, the operation execution unit 62, the pressure acquisition unit 64, the command correction unit 66, and the position acquisition unit 72 constitute a system for correcting the pressure command F according to the posture OR of the welding gun 14. C Device 90( Fig.11 ).

[0139] In the device 90, the position acquisition unit 72 acquires the position of the first pressure command F C_1When the welding gun 14 positioned in the reference posture OR0 is driven to pressurize the object to be pressurized (fixed tip 36 ) with the movable tip 44 , the first position PS1 is detected by the position sensor 68 (step S13 ).

[0140] In addition, the position acquisition unit 72 acquires the position of the first pressure command F C_1 The drive is positioned by the motion execution unit 62 to the nth teaching posture OR n The welding gun 14 is used to pressurize the object to be pressurized by the movable welding nozzle 44, and the second position PS2 is detected by the position sensor 68 (step S14). Then, the pressure obtaining unit 64 obtains the nth teaching posture OR by a predetermined calculation (specifically, the calculation using the above-mentioned formula (1)) based on the first position PS1 and the second position PS2. n The pressure F under the pressure is applied (step S15).

[0141] According to this configuration, the teaching posture OR can be acquired without using a physical sensor such as the above-mentioned pressure sensor 16. n Therefore, the operator can omit the manual setting of the pressure sensor 16, and can effectively use Fig.12 The process is automated, thereby simplifying the operation of obtaining the pressure F.

[0142] In the above-described embodiment, the processor 50 executes step S2 or S8 to position the welding gun 14 to all the teaching positions TP. n And teaching posture OR n The case where the pressure F is obtained in step S6 or S15 is described. However, the present invention is not limited to this. The processor 50 obtains the n-th teaching position TP as the instruction correction unit 66. n And teaching posture OR n The pressure command F C_1 ', it is also possible to calculate the pressure command F based on the obtained pressure command F C_1 ', nth teaching position TP n And the kth (k≠n) teaching position TP k , estimate the kth teaching position TP k And teaching posture OR k The pressure command F C_1 '.

[0143] For example, the processor 50 positions the welding gun 14 at the first teaching position TP1 and the teaching posture OR1 in step S2, and obtains the pressure F in the above-mentioned step S6 or S15. In addition, the processor 50 corrects the first pressure instruction F based on the obtained pressure F during the actual welding operation. C_1, and thus the pressure command F under the first teaching position TP1 and teaching posture OR1 is obtained C_1 '.

[0144] In this case, the processor 50 generates a pressure command F based on the obtained pressure command F. C_1 ', the first teaching position TP1 and the second teaching position TP2 (specifically, the coordinates of the robot coordinate system C1) specified in the welding operation program 200, and a predetermined operation using a predetermined approximate expression is performed, thereby being able to estimate the second pressure instruction F at the second teaching position TP2 and the second teaching posture OR2. C_1 This approximate formula is, for example, a formula that expresses a change (for example, a linear change) in the pressure force F from the first teaching position TP1 to the second teaching position TP2, and is determined in advance by the operator.

[0145] In this case, the processor 50 as the action execution unit 62 does not execute the action of positioning the welding gun 14 to the second teaching position TP2 and the second teaching posture OR2 in the above-mentioned step S8. According to this structure, for the second teaching posture OR2, the positioning action of step S8 and the action of obtaining the pressure F in step S15 can be canceled, and the second pressure instruction F in the second teaching posture OR2 can be estimated with high accuracy. C_1 '.

[0146] Next, refer to Fig.13 as well as Fig.14 , other functions of the welding robot system 80 are described. The welding robot system 80 also performs Fig.14 In addition, Fig.14 In the process shown, Fig.12 The same process is marked with the same step number and repeated descriptions are omitted.

[0147] exist Fig.14 In the process, when the processor 50 determines "No" in step S7, it executes step S21. In step S21, the processor 50 obtains the positioning command IN that has been executed. P The teaching postures specified in OR1, OR2, ...OR n The positioning command IN is executed next. P Teaching posture specified in OR n+1 The difference φ.

[0148] For example, the processor 50 in step S2 passes the welding operation program 200 ( Figure 6 )'s first line positioning command IN P After the welding gun 14 is positioned at the first teaching position TP1 and the teaching posture OR1, steps S3, S5, S14, S15, and S7 are executed, and the process proceeds to step 21.

[0149] In this case, the processor 50 obtains the first row positioning command IN in step S21. P The first teaching posture OR1 and the third line positioning command IN to be executed next P The difference between the specified second teaching posture OR2 1_2 Specifically, the processor 50 refers to the positioning command IN of the third line of the welding operation program 200. P : “MOVE[TP2]VELOCITY[V2]” obtains the coordinates (X2, Y2, Z2, W2, P2, R2) represented by the identifier “TP2” from the position data table 202.

[0150] Then, processor 50 executes the first row of the most recently executed positioning command IN P The coordinates (W1, P1, R1) of the first teaching posture OR1 and the coordinates (W2, P2, R2) of the second teaching posture OR2 obtained from the position data table 202 are used to calculate the difference φ between the first teaching posture OR1 and the second teaching posture OR2. 1_2 .

[0151] Below, we can find the difference φ 1＿2 First, the processor 50 represents the coordinates (W1, P1, R1) of the first teaching posture OR1 as a 3×3 matrix M1. In the matrix M1, the vector V represented by the three parameters in the first column 1_1 is a unit vector representing the rotation component about the x-axis of the tool coordinate system C2. The vector V represented by the three parameters in the second column is 1_2 is a unit vector representing the rotation component about the y-axis of the tool coordinate system C2, and the vector V represented by the three parameters in the third column 1_3 is a unit vector representing the rotation component about the z-axis of the tool coordinate system C2.

[0152] Similarly, the processor 50 represents the coordinates (W2, P2, R2) of the second teaching posture OR2 as a 3×3 matrix M2. Then, the processor 50 obtains the vector V of the first column of the matrix M1. 1_1 The vector V of the first column of the matrix M2 2_1 The inner product IP1. If the vector V 1＿1 With vector V 2＿1 The angle is set to φ x , then the inner product IP1 is expressed as cosφ x The angle φ x The difference φ between the first teaching posture OR1 and the second teaching posture OR2 in the direction around the x-axis of the tool coordinate system C2 is represented by 1＿2The processor 50 can calculate the inner product IP1=cosφ based on the obtained inner product IP1=cosφ x Find the angle φ x =cos -1 (IP1).

[0153] Similarly, processor 50 finds the vector V of the second column of matrix M1 1_2 The vector V of the second column of the matrix M2 2_2 The inner product IP2. If the vector V 1＿2 With vector V 2＿2 The angle is set to φ y , then the inner product IP2 is expressed as cosφ y The angle φ y The difference φ between the first teaching posture OR1 and the second teaching posture OR2 in the direction around the y-axis of the tool coordinate system C2 is represented by 1＿2 The processor 50 can calculate the inner product IP2=cosφ based on the obtained inner product IP2=cosφ y Find the angle φ y =cos -1 (IP2).

[0154] Thus, the processor 50 obtains the angle φ x and φ y As the difference φ between the first teaching posture OR1 and the second teaching posture OR2 1＿2 Therefore, the processor 50 obtains the difference φ between the first teaching posture OR1 and the second teaching posture OR2 1_2 The posture difference calculation unit 74 ( Fig.13 ) functions. The above method of obtaining the difference φ is an example, and the processor 50 may obtain the difference φ by any other method.

[0155] In step S22, the processor 50 determines whether the difference φ obtained in step S21 is smaller than a preset threshold φ th For example, the processor 50 uses the difference φ between the first teaching posture OR1 and the second teaching posture OR2 as in the previous step S21. 1_2 And find the angle φ x and φ y .

[0156] At this time, the processor 50 determines the angle φ in step S22 x Is it less than the preset threshold φ? th_x (i.e., φ x <φ th_x ) and angle φ y Is it less than the preset threshold φ? th_y (i.e., φ y <φ th_y ). The processor 50 satisfies φx <φ th_x And φ y <φ th_y When the first teaching posture OR1 and the second teaching posture OR2 are judged to be different, φ 1_2 Less than the threshold φ th (i.e., “yes”). On the other hand, in the case where φ x ≥φ th_x or φ y ≥φ th_y In the case of, the processor 50 determines that the difference φ between the first teaching posture OR1 and the second teaching posture OR2 1_2 is the threshold φ th above (ie, “no”).

[0157] Thus, in this embodiment, the processor 50 determines whether the difference φ obtained in step S21 1＿2 Is it less than a predetermined threshold value φ th The difference determination unit 76 ( Fig.13 ) functions. If the processor 50 determines "No" in step S22, it proceeds to step S8. Then, the processor 50 executes the positioning command IN of the third row in step S8. P , move the welding gun 14 to the second teaching position TP2 and the second teaching posture OR2, and return to step S3.

[0158] On the other hand, when the processor 50 determines "yes" in step S22, the process returns to step S7. That is, in the present embodiment, the processor 50 calculates the difference φ between the first teaching posture OR1 and the second teaching posture OR2. 1_2 If the position OR1 and the position OR2 are similar, the positioning command IN of the third row is not executed in step S8. P Then, the processor 50 considers that the pressure F is obtained for the second teaching position TP2 and the teaching posture OR2 in step S7.

[0159] Thus, in this embodiment, after the positioning command IN has been executed, P Specified teaching posture OR1, OR2...OR n At least one of them is consistent with the predetermined positioning command IN to be executed next P Specified teaching posture OR n+1 If the difference φ is small, the next positioning command IN is not executed. P , cancel the action of obtaining the pressure F.

[0160] For example, in Figure 7The four teaching postures shown are n The difference between the first teaching posture OR1 and the second teaching posture OR2 is φ 1_2 As mentioned above, it is less than the threshold value φ th In this case, the processor 50 in step S8 uses the positioning command IN of the fifth line of the welding operation program 200. P After the welding gun 14 is positioned at the third teaching position TP3 and the teaching posture OR3, steps S3, S5, S14, S15, and S7 are executed, and the process proceeds to step S21.

[0161] In this case, the processor 50 obtains the positioning command IN of the first row that has been executed in step S21. P The first teaching posture OR1 is specified and the positioning command IN of the seventh line to be executed next is P The difference between the fourth teaching posture OR4 is 1_4 , and the positioning command IN of the third line that has been executed P The difference between the third teaching posture OR3 and the fourth teaching posture OR4 is φ 3_4 .

[0162] Then, in step S22, when the difference φ 1＿4 and difference φ 3＿4 At least one of them is less than the threshold φ th , the processor 50 determines "yes". In this case, the processor 50 does not execute the positioning command IN of the seventh line. P , the step S15 of obtaining the pressure F in the fourth teaching posture OR4 is cancelled. That is, in the present embodiment, the processor 50 only performs the operation for the two positions that are not similar to each other (that is, the difference φ is the threshold φ). th Teaching posture of the above) OR n , the pressure F is obtained in step S15.

[0163] exist Fig.14 After the process, the processor 50 executes the welding operation program 200 for the actual welding operation. During the execution of the welding operation program 200, the processor 50 functions as the instruction correction unit 66 to correct each teaching posture OR based on the pressure F obtained in step S15. n The pressure command F C_1 , and thus the pressure command F is obtained C_1 '.

[0164] Here, in the present embodiment, the processor 50 selects a plurality of teaching postures OR whose differences φ are small (that is, similar). n For example, in step S22, since the difference φ between the first teaching posture OR1 and the second teaching posture OR2 1_2If the pressure F is small, it is determined as "yes", and the operation of obtaining the pressure F in step S15 is canceled.

[0165] In this case, the processor 50 functions as the command correction unit 66, and corrects the pressure command F for driving the welding gun 14 in the second teaching posture OR2 using the correction amount ΔF obtained for the first teaching posture OR1. C_1 For example, the correction amount ΔF obtained in the first teaching posture OR1 is ΔF=0.5 [kN] as described above.

[0166] In this case, the processor 50 executes the welding command IN of the fourth line of the welding operation program 200. W When the pressure command F for driving the welding gun 14 in the second teaching posture OR2 is set, C_1 (=2 [kN]) plus the correction amount ΔF (=1 [kN]) obtained in the first teaching posture OR1 to perform correction, and obtain a new pressure command F C_1 '=2.5[kN] (second pressure command). Then, the processor 50 executes the welding command IN of the fourth line. W When the new pressure command F C_1 '(=2.5 [kN]) drives the welding gun 14 positioned in the second teaching posture OR2.

[0167] Then, in step S22, due to the difference φ between the first teaching posture OR1 and the fourth teaching posture OR4 1＿4 In this case, the processor 50 functions as the command correction unit 66, and uses the correction amount ΔF (=0.5 [kN]) obtained for the first teaching posture OR1 to correct the pressure command F for driving the welding gun 14 in the fourth teaching posture OR4. C , so the new pressure command F C_1 '(=2.5[kN]).

[0168] Then, the processor 50 executes the welding command IN of the eighth line. W When the new pressure command F C_1 'Drive the welding gun 14 positioned in the fourth teaching posture OR4. That is, in this case, the processor 50 uses the common correction amount ΔF (=0.5 [kN]) to correct the original pressure command F in the first teaching posture OR1, the second teaching posture OR2, and the fourth teaching posture OR4. C_1 .

[0169] In addition, in this embodiment, it is described that in all teaching postures OR n The same value of pressure command F C_1 (Right now, Figure 8 The welding condition 1 shown in FIG. 1 is a case where the pressure F1 = 2 [kN]) is predetermined. However, the present invention is not limited to this, and a teaching posture OR may be set for each teaching posture. n Determine different pressure commands F C_1 In this case, you can also Figure 8 The welding condition 1 shown in the data table stores each teaching posture OR n Pressure command F C_1 .

[0170] As described above, in this embodiment, the processor 50 functions as the action execution unit 62, the pressure acquisition unit 64, the command correction unit 66, the position acquisition unit 72, the posture difference calculation unit 74, and the difference determination unit 76, thereby correcting the pressure command F according to the posture OR of the welding gun 14. C Therefore, the action execution unit 62, the pressure acquisition unit 64, the command correction unit 66, the position acquisition unit 72, the posture difference calculation unit 74, and the difference determination unit 76 constitute a system for correcting the pressure command F according to the posture OR of the welding gun 14. C The device 100 ( Fig.13 ).

[0171] In the device 100, the pressure acquiring unit 64 acquires the first pressure F when the operation executing unit 62 positions the welding gun 14 in the first teaching posture OR1 (step S15), and the command correcting unit 66 obtains the first pressure command F for driving the welding gun 14 in the first teaching posture OR1 based on the first pressure F. C_1 (=2[kN]) is corrected to the second pressure command F C_1 '(=2.5[kN]) correction amount ΔF(=0.5[kN]).

[0172] On the other hand, the posture difference calculation unit 74 obtains the difference φ between the first teaching posture OR1 and the second teaching posture OR2 1_2 (Step S21 ) The difference determination unit 76 determines the difference φ obtained by the posture difference calculation unit 74 1_2 Is it less than a predetermined threshold φ? th (Step S22). Then, when the difference determination unit 76 determines that the difference φ 1_2 Less than the threshold φ th (ie, in the case of “YES” in step S22 ), the operation execution unit 62 does not execute the operation of positioning the welding gun 14 to the second teaching posture OR2 (step S8 ).

[0173] Then, the command correction unit 66 corrects the first pressure command F for driving the welding gun 14 in the second teaching posture OR2 using the correction amount ΔF obtained in the first teaching posture OR1. C(=2[kN]), thereby obtaining the second pressure command F in the second teaching posture OR2. C_1 '(=2.5[kN]).

[0174] According to this configuration, it is possible to teach multiple postures OR with small differences φ between them. n Since the common correction amount ΔF is used between the two, the positioning operation of step S8 and the operation of obtaining the pressure F of step S15 can be eliminated. Fig.14 The cycle time of the process.

[0175] In addition, the difference determination unit 76 and the posture difference calculation unit 74 of the device 100 can also be applied to Figure 2 In this case, the processor 50 Figure 5 If the judgment in step S7 is "No", execute Fig.14 In step S21 and S22, when it is determined as "yes" in step S22, the process returns to step S7, and on the other hand, when it is determined as "no", the process proceeds to step S8.

[0176] In the present embodiment, the processor 50 is provided with a plurality of teaching postures OR in which the difference φ between each other is small (that is, similar). n The case where the common correction amount ΔF is used between the two has been described. However, the present invention is not limited to this, and the processor 50 may also use a plurality of teaching postures OR with small differences φ between them. n In the case of a teaching posture OR n The corrected second pressure command F C_1 'Sum difference φ, find other teaching postures OR n+1 The second pressure command F C_1 '.

[0177] For example, the processor 50 corrects the first pressure command F as described above in the first teaching posture OR1. C_1 To obtain the second pressure command F C_1 ', and the difference between the first teaching posture OR1 and the second teaching posture OR2 is φ 1_2 (That is, the angle φ x and φ y ) is smaller. In this case, the processor 50 may also calculate the difference φ according to 1_2 The angle φ around the y-axis of the tool coordinate system C2 orthogonal to the welding gun axis A2 y , so that the second pressure command F under the first teaching posture OR1 C_1 'Linear change, thereby obtaining the second pressure command F under the second teaching posture OR2 C_1 '.

[0178] For example, the second teaching posture OR2 is Figure 4 The first teaching posture OR1 is a posture from the second teaching posture OR2 to Figure 3 The posture shown is rotated by an angle φ around the y-axis of the tool coordinate system C2 y In this case, the processor 50 may also function as the instruction correction unit 66 by y The second pressure command F in the first teaching posture OR1 is C_1 'Increase linearly to obtain the second pressure command F in the second teaching posture OR2 C_1 '.

[0179] On the contrary, the first teaching posture OR1 is Figure 4 The second teaching posture OR1 is a posture from the first teaching posture OR1 to Figure 3 The posture shown is rotated by an angle φ around the y-axis of the tool coordinate system C2 y In this case, the processor 50 may also function as the instruction correction unit 66 by y The second pressure command F in the first teaching posture OR1 is C_1 'Linearly reduce to obtain the second pressure command F in the second teaching posture OR2 C_1 '.

[0180] Thus, in the present embodiment, the command correction unit 66 generates the second pressure command F in the first teaching posture OR1 based on the second pressure command F in the first teaching posture OR1. C_1 ' and the difference φ (e.g., the angle φ y ), find the second pressure command F under the second teaching posture OR2 C_1 According to this structure, for the second teaching posture OR2, the positioning action of step S8 and the action of obtaining the pressure F of step S15 can be canceled, and the second pressure instruction F under the second teaching posture OR2 can be obtained with high accuracy based on the difference φ. C_1 '.

[0181] In addition, the processor 50 selects a plurality of teaching postures OR when there are a plurality of teaching postures OR with a small difference φ between them. n In the case of a teaching posture, it can also be based on a teaching posture or n The correction amount ΔF and the difference φ obtained below are used to obtain other teaching postures OR n+1 For example, the correction amount ΔF is obtained in the first teaching posture OR1 as described above, and the difference φ between the first teaching posture OR1 and the second teaching posture OR2 1_2 In this case, the processor 50 may also calculate the value of the angle φ around the y-axis of the tool coordinate system C2 orthogonal to the welding gun axis A2. y, the correction amount ΔF obtained in the first teaching posture OR1 is linearly changed, thereby obtaining the correction first pressure command F in the second teaching posture OR2 C_1 The correction amount ΔF.

[0182] For example, the second teaching posture OR2 is Figure 4 The first teaching posture OR1 is a posture from the second teaching posture OR2 toward Figure 3 The posture shown is rotated by an angle φ around the y-axis of the tool coordinate system C2 y In this case, the processor 50 may also function as the instruction correction unit 66 by y The correction amount ΔF in the first teaching posture OR1 is linearly increased to obtain the correction first pressure command F in the second teaching posture OR2. C_1 The correction amount ΔF.

[0183] On the contrary, the first teaching posture OR1 is Figure 4 The second teaching posture OR1 is a posture from the first teaching posture OR1 toward Figure 3 The posture shown is rotated by an angle φ around the y-axis of the tool coordinate system C2 y In this case, the processor 50 may also function as the instruction correction unit 66 by y The correction amount ΔF in the first teaching posture OR1 is linearly reduced to obtain the correction first pressure command F in the second teaching posture OR2. C_1 The correction amount ΔF.

[0184] Next, refer to Figure 15 to Figure 17 , other functions of the welding robot system 10 are described. The welding robot system 10 also performs Fig.16 In this embodiment, the processor 50 generates a flow chart for reproducing each teaching posture OR specified in the welding operation program 200. n , and in each teaching posture OR n The posture reproduction program 204 for acquiring the pressure F.

[0185] exist Fig.16 After the process starts, the processor 50 executes step S1 to obtain the welding operation program 200. In step S31, the processor 50 extracts the teaching posture OR from the welding operation program 200. n Specifically, the processor 50 analyzes the welding operation program 200 and extracts all positioning commands IN specified in the welding operation program 200. P .

[0186] Then, the processor 50 extracts the positioning command IN PThe code contains the identifier [TPn] from the position data table 202 ( Figure 7 ) obtains the teaching posture indicated by the identifier [TPn] OR n As a result, the processor 50 extracts the coordinates (W1, P1, R1) representing the first teaching posture OR1, the coordinates (W2, P2, R2) representing the second teaching posture OR2, the coordinates (W3, P3, R3) representing the third teaching posture OR3, and the coordinates (W4, P4, R4) representing the fourth teaching posture OR4. Thus, in the present embodiment, the processor 50 extracts the teaching posture OR1 from the welding operation program 200. n The posture extraction unit 78 ( Fig.15 ) to perform its function.

[0187] In step S32, the processor 50 determines whether an input of a gesture reproduction position OP is received. The gesture reproduction position OP is obtained by executing the gesture reproduction program 204 (described later). Fig.19 ) is the position (specifically, coordinates (X, Y, Z)) of the robot coordinate system C1 for positioning the welding gun 14 (in other words, TCP) when the welding gun 14 is positioned.

[0188] For example, the processor 50 generates an input image IM for inputting the posture reproducing position OP, and displays it on the display device 60. The operator operates the input device 58 while visually checking the input image IM, and provides the processor 50 with an input for designating the coordinates of the posture reproducing position OP. Hereinafter, a case where the operator designates the coordinates (X0, Y0, Z0) of the robot coordinate system C1 as the posture reproducing position OP will be described.

[0189] The coordinates (X0, Y0, Z0) of the posture reproduction position OP correspond to at least one (for example, all) teaching positions TP specified in the welding work program 200. n (X n , Y n , Z n ) is different from the coordinates specified by the operator than the at least one teaching position TP n The coordinates closer to the origin of the robot coordinate system C1 (ie, the robot base 20 ).

[0190] When the processor 50 receives the input of the posture reproduction position OP from the operator, it determines that it is "yes" and proceeds to step S33. On the other hand, when it determines that it is "no", it loops through step S32. n The input receiving unit 84 ( Fig.15 ) to perform its function.

[0191] In step S33, the processor 50 performs the teaching posture OR based on the teaching posture OR extracted in step S31. n , generating the gesture reproduction program 204. Specifically, the processor 50 first generates the gesture reproduction program 204 based on the teaching gesture OR extracted in step S31. n The position data table 206 for the gesture reproduction program 204 is generated based on the gesture reproduction position OP received in step S32.

[0192] Fig.18 An example of the position data table 206 is shown. Fig.18 The position data table 206 shown in FIG. 1 stores coordinate data to which identifiers "OP1", "OP2", "OP3" and "OP4" are assigned, respectively. Fig.18 As shown, the coordinates of the identifier "OPn" (n = 1, 2, 3, 4) share the coordinates (X0, Y0, Z0) of the posture reproduction position OP received in step S32, and on the other hand, each has the teaching posture OR extracted in step S31. n The coordinates (W n , P n , R n ). The processor 50 performs the teaching posture OR based on the teaching posture OR extracted in step S31. n and the posture reproduction position OP accepted in step S32, generating Fig.18 The position data table 206 is shown.

[0193] Next, the processor 50 generates the gesture reproduction program 204 based on the generated position data table 206 . Fig.19 An example of the gesture reproduction program 204 is shown. Fig.19 In the posture reproduction program 204 shown in the figure, for example, the code "MOVE[OP3]VELOCITY[V13]" in the fifth line is used to move the welding gun 14 with the robot 12 at a speed V=V 13 [mm / sec] Move and position to the posture reproduction position OP indicated by the identifier [OP3] and the positioning command IN of the teaching posture OR3 O .

[0194] In addition, the speed V specified by the gesture reproduction program 204 n : "VELOCITY[Vn]" (n=11, 12, 13, 14) can be set to the velocity V specified in the welding operation program 200. n (n=1, 2, 3, 4) different (specifically, low) speeds (e.g., V 11 =V 12 =V 13 =V 14 <V1=V2=V3=V4)。

[0195] When the processor 50 executes the gesture reproduction program 204, when it reads the positioning command IN of the fifth line O , the coordinates (X0, Y0, Z0, W3, P3, R3) indicated by the identifier "OP3" are obtained from the position data table 206. Furthermore, the processor 50 functions as the action execution unit 62, and moves the robot 12 in the robot coordinate system C1 to position the welding gun 14 to the coordinates (X0, Y0, Z0, W3, P3, R3).

[0196] On the other hand, the code "PRESSURIZE CONDITION [1]" in the 2ith line (i=1, 2, 3, 4) of the posture reproduction program 204 is a pressurization command IN for driving the servo motor 40 of the welding gun 14 according to the welding condition 1 assigned with the identifier [1], so that the welding gun 14 pressurizes the object to be pressurized. R Thus, the posture reproduction program 204 does not include the welding command IN specified in the welding operation program 200. W .

[0197] When the processor 50 executes the gesture reproduction program 204, it reads the pressure command IN R When the welding condition 1 data table with the identifier [1] is referred to, the pressure F1=2[kN] is obtained, and the pressure instruction F corresponding to the pressure F1 is used. C_1 (=2 [kN]) to drive the servo motor 40 of the welding gun 14.

[0198] Thus, in this embodiment, the processor 50 performs the teaching posture OR based on the teaching posture OR extracted in step S31. n The position data table 206 is generated based on the posture reproduction position OP received in step S32, and the posture reproduction program 204 is generated based on the position data table 206. Therefore, the processor 50 performs the teaching posture reproduction program based on the teaching posture OR n and the program generation unit 82 ( Fig.15 ) to perform its function.

[0199] Refer again Fig.16 In step S34, the processor 50 determines whether a posture reproduction program start instruction is received from the operator or the host controller. If the processor 50 determines that it is "yes", it proceeds to step S35. On the other hand, if the processor determines that it is "no", it loops through step S34.

[0200] In step S35, the processor 50 executes a pressure obtaining process. Fig.17 This step S35 is described. Fig.17 In the process shown, Figure 5The same steps are marked with the same step numbers and repeated descriptions are omitted.

[0201] In step S41, the processor 50 executes the positioning command IN of the gesture reproduction program 204. O Specifically, the processor 50 functions as the motion execution unit 62 and reads the positioning instruction IN of "MOVE[OP1]VELOCITY[V11]" specified in the first line of the gesture reproduction program 204. O , the robot 12 makes the welding gun 14 move at a speed V 11 Move so as to be positioned at the posture reproduction position OP and the teaching posture OR1 (ie, the coordinates (X0, Y0, Z0, W1, P1, R1) of the identifier “OP1”).

[0202] In step S42, the processor 50 determines whether the welding gun 14 is positioned at the posture reproducing position OP and the nth teaching posture OR. n (i.e., the coordinates (X0, Y0, Z0, W n , P n , R n Specifically, the processor 50 determines whether the welding gun 14 is positioned at the posture reproducing position OP and the n-th teaching posture OR based on the feedback FB2 from the rotation detection sensor RS1. n .

[0203] The processor 50 determines that the welding gun 14 is positioned at the posture reproduction position OP and the nth teaching posture OR n (ie, "Yes"), the operation of the robot 12 is stopped and the process proceeds to step S4. Thus, the welding gun 14 is positioned at the posture reproducing position OP and the nth teaching posture OR n On the other hand, when the determination result is "No", the processor 50 executes step S42 in a loop.

[0204] After step S4, in step S43, the processor 50 performs the welding according to the pressure F specified in the welding condition m. m Corresponding pressure command F C_m (first pressure command) to drive the welding gun 14. Specifically, the processor 50 reads the pressure command IN of the 2ith line in the posture reproduction program 204. R .

[0205] Then, in step S43, the processor 50 reads the pressure command IN RThe processor 50 obtains the pressure F1 (=2 [kN]) specified by the welding condition 1 assigned with the identifier [1] by using a code such as "CONDITION [1]" of FIG. 1. Then, the processor 50 generates a pressure command F corresponding to the pressure F1 obtained from the welding condition 1. C_1 (=2[kN]), according to the pressure command F C_1 A servo motor 40 drives the welding gun 14 .

[0206] Then, the processor 50 generates a signal when the feedback FB1 from the load detection sensor LS is equal to the pressure command F C_1 When the corresponding value is reached, the servo motor 40 is stopped. As a result, the pressure sensor 16 is clamped between the movable welding tip 44 and the fixed welding tip 36. Next, the processor 50 executes step S6, functions as a pressure acquisition unit 64, and acquires from the pressure sensor 16 the pressure F measured by the pressure sensor 16 at the end of step S43 (i.e., when the servo motor 40 is stopped).

[0207] In step S44, the processor 50 determines whether all the teaching postures OR specified in the posture reproduction program 204 are n The pressure F is obtained. If the processor 50 determines that it is "yes", the process ends. Fig.17 The process shown ends here Fig.16 On the other hand, when the determination result is "No", the processor 50 proceeds to step S45.

[0208] In step S45, the processor 50 executes the positioning command IN specified in the next line of the gesture reproduction program 204. O For example, when executing step S45 for the first time, the processor 50 executes the positioning command IN of the third row. O "MOVE[OP2]VELOCITY[V12]" moves the welding gun 14 at a speed of V 12 Move it to be positioned at the posture reproduction position OP and the second teaching posture OR2.

[0209] Then, the processor 50 returns to step S42. In this way, the processor 50 repeatedly executes the loop of steps S42, S4, S43, S6, S44 and S45 until the determination in step S44 is "yes", and each time the welding gun 14 is positioned at the posture reproduction position OP and the nth teaching posture OR in step S45, n When the pressure F is obtained in step S6.

[0210] That is, according to the posture reproduction program 204, the processor 50 executes steps S41 and S45, without changing the position of the welding gun 14 (i.e., the posture reproduction position OP) (i.e., maintaining it at the posture reproduction position OP), and only changes the posture of the welding gun 14 to the teaching posture OR. n Changes are made, and the pressure F is obtained in step S6.

[0211] In the End Fig.17 After the process shown in the figure, the processor 50 executes the welding operation program 200 to perform the actual welding operation on the workpiece. When the welding operation program 200 is executed for the actual welding operation, the processor 50 functions as the instruction correction unit 66 to correct each teaching posture OR based on the pressure F obtained in step S6 in step S35. n The pressure command F C_1 , and thus the pressure command F is obtained C_1 '.

[0212] As described above, in this embodiment, the processor 50 functions as the action execution unit 62, the pressure acquisition unit 64, the command correction unit 66, the posture extraction unit 78, the program generation unit 82, and the input reception unit 84, thereby correcting the pressure command F according to the posture OR of the welding gun 14. C Therefore, the action execution unit 62, the pressure acquisition unit 64, the command correction unit 66, the posture extraction unit 78, the program generation unit 82, and the input receiving unit 84 constitute a system for correcting the pressure command F according to the posture OR of the welding gun 14. C Device 110 ( Fig.15 ).

[0213] In the device 110, the operation execution unit 62 executes an operation including causing the robot 12 to operate so as to position the welding gun 14 to the teaching position TP. n Different pose reproduction positions OP and teaching poses OR n Positioning command IN O On the other hand, it does not include welding commands IN W The posture reproduction program 204 is used to position the welding gun 14 to the posture reproduction position OP and the teaching posture OR by the robot 12. n (Steps S41, S45).

[0214] Then, the pressure acquiring unit 64 acquires the position of the welding gun 14 at the posture reproducing position OP and the teaching posture OR by the operation executing unit 62. n According to this structure, by executing the teaching posture OR specified in the reproduction welding operation program 200, n The posture reproduction program 204 can position the welding gun 14 to the teaching posture OR n, and effectively obtain the teaching posture for correcting the OR n The pressure command F C The added pressure F.

[0215] In the device 110, the posture extraction unit 78 extracts the teaching posture OR from the welding work program 200. n (Step S31), the program generation unit 82 generates a teaching posture OR based on the teaching posture OR extracted by the posture extraction unit 78. n , generating the gesture reproduction program 204. According to this structure, the computer can automatically generate the gesture reproduction program 204, thereby reducing the operator's work.

[0216] In addition, in the device 110, the input receiving unit 84 receives the input of the posture reproduction position OP (step S32), and the program generating unit 82 generates the posture reproduction program 204 based on the posture reproduction position OP received by the input receiving unit 84. According to this structure, the operator can arbitrarily specify the posture reproduction position OP as a coordinate close to the origin (robot base 20) of the robot coordinate system C1. As a result, the motion range of the robot 12 when executing the posture reproduction program 204 can be reduced, so that the robot 12 can reliably prevent interference with peripheral devices when executing the posture reproduction program 204.

[0217] Furthermore, in the above-mentioned step S32, the processor 50 may function as the input receiving unit 84 and receive the input of the allowable motion range RG of the robot 12 instead of the posture reproduction position OP. For example, the processor 50 generates an input image IM for inputting the allowable motion range RG and displays it on the display device 60. The operator may also operate the input device 58 while visually checking the input image IM to provide the processor 50 with an input for specifying the allowable motion range RG (for example, an input for specifying the radius R from the origin of the robot coordinate system C1).

[0218] In this case, after the processor 50 determines "yes" in step S32, in step S33, based on the teaching posture OR extracted in step S31, n The position data table 206' is generated based on the allowable motion range RG received in step S32. Fig. 20 An example of the position data table 206 ′ is shown.

[0219] exist Fig. 20 In the example shown, the coordinates assigned with the identifier "OPn" (n=1, 2, 3, 4) stored in the position data table 206' have the coordinates (X j , Y j , Z j)(j=11, 12, 13, 14). The coordinates (X j , Y j , Z j ) and at least one (e.g., all) teaching positions TP specified in the welding operation program 200 n (X n , Y n , Z n ) is different and is automatically generated by the processor 50 as the coordinates within the allowed motion range RG accepted in step S32.

[0220] Then, the processor 50 functions as the program generation unit 82 in step S33 to generate the posture reproduction program 204 based on the position data table 206'. That is, in this case, the processor 50 functions as the program generation unit 82 to generate the posture reproduction program 204 based on the teaching posture OR extracted by the posture extraction unit 78 in step S31. n The gesture reproduction program 204 is generated based on the allowable motion range RG received as the input receiving unit 84 in step S32.

[0221] Next, refer to Figure 21 to Figure 23 Another function of the welding robot system 80 is described. The welding robot system 80 also performs Fig. 22 In addition, Fig. 22 In the process shown, Fig.16 The same steps are marked with the same step numbers and repeated descriptions are omitted.

[0222] exist Fig. 22 After the process starts, the processor 50 executes step S1 to obtain the welding operation program 200, and then executes step S31 to function as the posture extraction unit 78 to extract the teaching posture OR from the welding operation program 200. n Next, the processor 50 executes step S32 to determine whether the input of the gesture reproduction position OP (X0, Y0, Z0) has been received.

[0223] If the result of the determination in step S32 is “Yes” (i.e., the input of the posture reproduction position OP (X0, Y0, Z0) is received), in step S51, the processor 50 functions as the posture difference calculation unit 74 to obtain the plurality of teaching postures OR extracted from the welding operation program 200 in step S31. n The difference between φ.

[0224] Specifically, the processor 50 obtains the difference φ between the first teaching posture OR1 (W1, P1, R1) and the second teaching posture OR2 (W2, P2, R2) by the method described in the above step S21. 1_2, the difference φ between the first teaching posture OR1 (W1, P1, R1) and the third teaching posture OR3 (W3, P3, R3) 1_3 and the difference φ between the first teaching posture OR1 (W1, P1, R1) and the fourth teaching posture OR4 (W2, P2, R2) 1_4 .

[0225] In addition, the processor 50 obtains the difference φ between the second teaching posture OR2 (W2, P2, R2) and the third teaching posture OR3 (W3, P3, R3). 2_3 , the difference φ between the second teaching posture OR2 (W2, P2, R2) and the fourth teaching posture OR4 (W4, P4, R4) 2_4 and the difference φ between the third teaching posture OR3 (W3, P3, R3) and the fourth teaching posture OR4 (W4, R4, R4) 3_4 .

[0226] In step S52, the processor 50 functions as the difference determination unit 76 to determine whether each difference φ obtained in step S51 is smaller than a preset threshold value φ. th Specifically, processor 50 converts the difference φ 1＿2 , difference φ 1＿3 , difference φ 1＿4 , difference φ 2＿3 , difference φ 2＿4 and difference φ 3＿4 Respectively with the threshold φ th Compare and determine whether it is φ 1＿2 <φ th ,φ 1＿3 <φ th ,φ 1＿4 <φ th ,φ 2＿3 <φ th ,φ 2＿4 <φ th or φ 3＿4 <φ th .

[0227] Assume that, as described in the above embodiment, the difference φ between the first teaching posture OR1, the second teaching posture OR2, and the fourth teaching posture OR4 is smaller than the threshold value φ th In the case of 1＿2 <φ th ,φ 1＿4 <φ th and φ 2＿4 <φ th .

[0228] In step S53, the processor 50 functions as the program generation unit 82 to generate the posture reproduction program 204. Specifically, the processor 50 generates the posture reproduction program 204 based on the plurality of teaching postures OR extracted in step S31. n The difference φ in is the threshold φ th The above teaching posture OR n and the gesture reproduction position OP accepted in step S32, a position data table 206" for the gesture reproduction program 204 is generated.

[0229] In the present embodiment, in the above step S52, it is determined that the difference φ between the first teaching posture OR1, the second teaching posture OR2, and the fourth teaching posture OR4 is smaller than the threshold value φ. th (That is, satisfying φ 1＿2 <φ th ,φ 1＿4 <φ th ,φ 2＿4 <φ th ). Therefore, the processor 50 generates a first teaching posture OR1 and a third teaching posture OR3 based on the posture reproduction position OP received in step S32. Fig.24 The position data table 206 is shown.

[0230] Then, the processor 50 generates a Fig.25 The gesture reproduction program 204' shown in FIG. The gesture reproduction program 204' includes the positioning command IN of the 2i-1th line (i=1, 2). O and the pressure command IN on line 2i R Afterwards, the processor 50 executes step S34, and when the determination is "yes", proceeds to step S54.

[0231] In step S54, the processor 50 executes a pressing force acquisition process. Fig.23 Indicates the pressure acquisition process. Fig.23 In the process shown, Fig.12 or Fig.17 The same steps are marked with the same step numbers and repeated descriptions are omitted.

[0232] The processor 50 executes the above steps S41 to S43, S14, S15, S44 and S45 according to the posture reproduction program 204' generated in step S53 to obtain the pressure F. As a result, the processor 50 obtains the pressure F in the first teaching posture OR1 and the pressure F in the third teaching posture OR3.

[0233] In the End Fig.23After the process, the processor 50 executes the welding operation program 200 for the actual welding operation. During the execution of the welding operation program 200, the processor 50 functions as the instruction correction unit 66, and based on the pressure F obtained in step S15 in step S54, the correction amount ΔF in the first teaching posture OR1 and the third teaching posture OR3 is respectively obtained, and the original pressure instruction F is respectively corrected by using the correction amount ΔF. C_1 , respectively calculate the pressure command F under the first teaching posture OR1 and the third teaching posture OR3 C_1 '.

[0234] On the other hand, the processor 50 corrects the original pressure command F for the second teaching posture OR2 and the fourth teaching posture OR4 using the correction amount ΔF obtained for the first teaching posture OR1. C_1 In this way, the processor 50 obtains the pressure command F in the second teaching posture OR2 and the fourth teaching posture OR4 respectively. C_1 That is, the processor 50 uses the common correction amount ΔF to correct the original pressure command F in the first teaching posture OR1, the second teaching posture OR2, and the fourth teaching posture OR4 that are similar to each other. C_1 .

[0235] As described above, in this embodiment, the processor 50 functions as the action execution unit 62, the pressure acquisition unit 64, the command correction unit 66, the position acquisition unit 72, the posture difference calculation unit 74, the difference determination unit 76, the posture extraction unit 78, the program generation unit 82, and the input reception unit 84, thereby correcting the pressure command F according to the posture OR of the welding gun 14. C .

[0236] Therefore, the operation execution unit 62, the pressure acquisition unit 64, the command correction unit 66, the position acquisition unit 72, the posture difference calculation unit 74, the difference determination unit 76, the posture extraction unit 78, the program generation unit 82, and the input reception unit 84 constitute a method for correcting the pressure command F according to the posture OR of the welding gun 14. C Device 120 ( Fig.21 ).

[0237] In the device 120, a plurality of teaching postures OR n In the example, only the difference φ between the two postures OR is used as the threshold φ. th The teaching posture OR of the above (i.e., posture OR different) n , the posture reproduction program 204' is generated. According to this configuration, the number of postures OR for positioning the welding gun 14 by the posture reproduction program 204' can be optimized.

[0238] In addition, in this embodiment, the processor 50 may also generate in step S53 Fig.19 The gesture reproduction program 204 shown in FIG. 204 is used instead of the gesture reproduction program 204′. In this case, the gesture reproduction program 204 can be replaced by the gesture reproduction program 204′. Fig. 22 The process omits steps S51 and S52. Fig.23 After the determination in step S44 is "No", execute Fig.14 Steps S21 and S22 are shown.

[0239] In addition, Fig.15 and Fig.21 In the embodiment of the present invention, the processor 50 functions as the program generation unit 82 to generate the posture reproduction programs 204 and 204'. However, the present invention is not limited to this. Fig.15 or Fig.21 In the embodiment of FIG. 5 , the processor 50 may obtain the posture reproduction program 204 or 204 ′ by downloading it from another computer (host controller, production management server, etc.), for example.

[0240] In this case, the gesture extraction unit 78, the program generation unit 82, and the input reception unit 84 can be omitted from the device 110 or 120. In this case, the processor 50 executes the downloaded gesture reproduction program 204 or 204'. Fig.17 Step S35 or Fig.23 Step S54 is shown.

[0241] In addition, in the above-mentioned embodiment, it is described that the processor 50 corrects the pressure command F when executing the welding operation program 200 for the actual welding operation. C_1 However, the processor 50 may also Figure 5 , Fig.12 , Fig.14 , Fig.16 or Fig. 22 During the execution of the process, the pressure command F is corrected. C_1 .

[0242] For example, in Figure 5 , Fig.12 or Fig.14 In the process, the processor 50 may also correct each teaching posture OR based on the pressure F collected in step S6 or S15 when the judgment is "yes" in step S7. n The pressure command F C_1 , and thus the pressure command F is obtained C_1 '. Furthermore, the processor 50 may also generate a plurality of teaching postures OR n The pressure command F is obtained C_1 'OR with this teaching posture nCreate and store the associated data table DT.

[0243] In this case, the processor 50 reads the welding command IN of the welding operation program 200 during the actual welding operation. W When the welding gun 14 is positioned at that time, the teaching posture OR is obtained from the data table DT. n (That is, the welding command IN W The previous line positioning command IN P Specified teaching posture OR n ) corresponds to the pressure command F C_1 '.

[0244] And, in Fig.16 or Fig. 22 In the process, the processor 50 may also correct each teaching posture OR according to the pressure F collected in step S6 or S15 at the end of step S35 or S54 (i.e., when it is determined to be "yes" in step S44). n The pressure command F C_1 , and thus the pressure command F is obtained C_1 '.

[0245] In addition, Figure 5 In the process of FIG. 1 , it is described that the processor 50 in step S2 or S8 causes the welding gun 14 to follow the positioning command IN of the welding operation program 200 through the robot 12. P (Code such as "Vn") specifies the speed V n However, the processor 50 may also be Figure 5 In step S2 or S8, the welding gun 14 is operated at a speed V specified in the welding operation program 200. n Different (for example, the ratio of speed V n Low) speed V n In this case, the control device 18 may be set to move the welding gun 14 at a speed V n Alternatively, in the welding operation program 200 obtained in the above step S1, the positioning command IN may be P The code is assigned to the flag FL'.

[0246] In the above-mentioned embodiment, the processor 50 in steps S5 and S43 generates a signal when the feedback FB1 from the load detection sensor LS is equal to the pressure command F. C_1 However, the present invention is not limited thereto, and in step S5 or S43, the processor 50 may stop the servo motor 40 when the movable welding tip 44 abuts against the non-pressurized object (fixed welding tip 36) and is forcibly stopped.

[0247] In this case, the processor 50 may also execute the welding command IN of the welding operation program 200 in the actual welding operation. W When the movable welding tip 44 abuts against the workpiece and is forcibly stopped, the servo motor 40 is stopped. In addition, the object to be pressed is not limited to the fixed welding tip 36, and any object fixed to the fixed arm 34 (for example, an iron plate) can be applied.

[0248] In addition, the processor 50 may also execute the computer program PG2 pre-stored in the memory 52. Figure 5 , Fig.12 , Fig.14 , Fig.16 or Fig. 22 In addition, the functions of the device 70, 90, 100, 110 or 120 executed by the processor 50 (i.e., the action execution unit 62, the pressure acquisition unit 64, the instruction correction unit 66, the position acquisition unit 72, the posture difference calculation unit 74, the difference determination unit 76, the posture extraction unit 78, the program generation unit 82, the input reception unit 84) may also be functional modules implemented by the computer program PG.

[0249] also, Figure 6 The welding operation procedure 200 shown, Fig.19 The gesture reproduction program 204 shown and Fig.25 The gesture reproduction program 204' shown is an example and may include any other type of commands. Figure 6 In the welding operation program 200 shown in FIG. 2i-1, the positioning command IN is specified. P , in line 2i, the welding command IN is specified W However, in the welding operation program 200, the positioning command IN may be specified in the i-th row (ie, the same row). P and welding command IN W .

[0250] Similarly, in the gesture reproduction program 204 or 204', the positioning command IN may be specified in the i-th line (the same line). O and pressurization command IN R In addition, the teaching position TP specified in the welding operation program 200 n And teaching posture OR n The number of is not limited to 4, and may be 1 or 5 or more. The teaching posture OR specified in the posture reproduction program 204 or 204' n The same is true for the number of .

[0251] In addition, Figure 6 In the welding operation program 200 shown in FIG. 1 , it is described that in the positioning command IN PThe identifier "TPn" (n = 1, 2, 3, 4) is specified in Figure 7 However, the present invention is not limited to this, and the positioning command IN may be used. P In the code, the coordinates (X n , Y n , Z n , W n , P n , R n ). Regarding the positioning command IN of the gesture reproduction program 204 or 204' O Same here.

[0252] In addition, Figure 6 In the welding operation program 200 shown in FIG. 1 , the welding command IN is described. W The identifier [m] corresponding to the welding condition m is recorded in Figure 6 In the example, m = 1), prepare Figure 8 However, the present invention is not limited to this, and the welding command IN may be used. W In the code, the value of welding condition m (i.e., pressure F) is directly recorded instead of the identifier "m". m , welding current I m , welding time t m ) Regarding the pressure command IN of the gesture reproduction program 204 or 204' R Same here.

[0253] In addition, the operator may also change the welding operation program 200 obtained in the above step S1 in the positioning command IN P (Specifically, teach posture OR n ) is changed to form the welding operation program 200'. Furthermore, the processor 50 may also perform the welding operation by executing the changed welding operation program 200' during the actual welding operation.

[0254] For example, the operator may change the welding operation program 200 ( Figure 6 ) program name, you can also edit or add positioning commands IN in the welding operation program 200 P Codes other than FL may also be assigned to the above-mentioned flag FL.

[0255] Alternatively, the operator may also input the welding command IN of the welding operation program 200 acquired in step S1. W The command is replaced with a command for executing the pressure obtaining operation FO, and the processor 50 executes the welding operation program 200′ according to the replaced welding operation program 200′. Figure 5 , Fig.12 or Fig.14 The welding operation program 200 acquired in step S1 and the welding operation program 200' after such a change can both be regarded as welding operation programs for causing the robot 12 and the welding gun 14 to perform welding operations.

[0256] In addition, the welding operation program 200 or 200' may also have multiple programs. For example, Figure 6 The welding work program 200 shown may be composed of a first program 200A including command codes of the first to fourth lines and a second program 200B including command codes of the fifth to eighth lines. Similarly, the posture reproduction program 204 or 204' may include a plurality of programs.

[0257] In the above embodiment, the case where welding condition 1 (ie, code “CONDITION[1]”) assigned with identifier [1] is used in welding work program 200 and posture reproduction programs 204 and 204 ′ is described, but other welding conditions m may be used.

[0258] In the above-mentioned embodiment, it is described that the processor 50 obtains the correction amount ΔF when performing the actual welding operation, and corrects the first pressure command F using the correction amount ΔF. C_1 , and then the second pressure command F is obtained C_1 However, the processor 50 may also determine each teaching posture OR before the actual welding operation based on the pressure F obtained in the above-mentioned step S6 or S15. n The second pressure command F C_1 '.

[0259] At this time, the processor 50 can determine the second pressure command F using the correction amount ΔF obtained as described above. C_1 Alternatively, the correction amount ΔF may be omitted and the first pressure command F may be used. C_1 and any operation of the pressure F to determine the second pressure command F C_1 '. Moreover, the processor 50 may also use a predetermined second pressure command F during the execution of the actual welding operation (ie, the welding operation program 200, 200'). C_1 'Replace the first pressure command F C_1 to make corrections.

[0260] In addition, in the above-mentioned embodiment, the situation in which the functions of devices 70, 90, 100, 110 and 120 (action execution unit 62, pressure acquisition unit 64, instruction correction unit 66, position acquisition unit 72, posture difference calculation unit 74, difference judgment unit 76, posture extraction unit 78, program generation unit 82, input receiving unit 84) are installed in the control device 18 is described.

[0261] However, the present invention is not limited thereto, and at least one of the functions of the device 70, 90, 100, 110, or 120 (e.g., the action execution unit 62, the posture extraction unit 78, the program generation unit 82, the input reception unit 84) may be installed in a teaching device (a teaching pendant, a tablet terminal device, etc.) or other computers such as a PC that teaches the robot 12 actions. In this case, the processor of the other computer functions as the device 70, 90, 100, 110, or 120.

[0262] In addition, the robot 12 is not limited to a vertical multi-joint robot, but may be any other type of robot such as a horizontal multi-joint robot or a parallel robot. In addition, the concept of the present invention is not limited to a C-type spot welding gun, and may be applied to any other type of welding gun such as an X-type spot welding gun. The present disclosure is described above through the embodiments, but the above embodiments do not limit the invention involved in the scope of the patent protection requested.

[0263] Description of Reference Numerals

[0264] 10, 10', 80 welding robot system;

[0265] 12 robots;

[0266] 14 welding gun;

[0267] 16, 16' with pressure sensor;

[0268] 18. Control device;

[0269] 62 action execution unit;

[0270] 64: pressure obtaining unit;

[0271] 66 instruction correction department;

[0272] 70, 90, 100, 110, 120 devices;

[0273] 72 position acquisition unit;

[0274] 74 posture difference calculation unit;

[0275] 76 difference determination unit;

[0276] 78 posture extraction unit;

[0277] 82 Program Generation Department;

[0278] 84 input receiving unit;

[0279] 200 welding operation procedures;

[0280] 204, 204' Posture reproduction program.

Claims

1. A device that corrects a pressure command based on the posture of a welding gun, the pressure command defining the pressure of the welding gun when a robot moves and pressurizes a workpiece for welding, characterized in that: The device comprises: an action execution unit that causes the robot to perform an action so as to position the welding gun to a teaching posture specified by a welding operation program that causes the robot and the welding gun to perform a welding operation; a pressure obtaining unit for obtaining the pressure when the welding gun is driven by a first pressure instruction when the operation executing unit positions the welding gun to the teaching posture; as well as A command correction unit corrects the first pressure command based on the pressure acquired by the pressure acquisition unit, thereby obtaining a second pressure command when the welding gun is driven in the teaching posture when the welding work program is executed.

2. The device according to claim 1, characterized in that The welding operation program includes: a positioning command for causing the robot to move the welding gun to the taught position and the taught posture; and a welding command for starting the welding gun to weld the workpiece. The action execution unit executes the positioning command of the welding operation program to position the welding gun to the teaching position and the teaching posture through the robot, while not executing the welding command. The pressure obtaining unit obtains the pressure when the operation executing unit positions the welding gun to the teaching position and the teaching posture.

3. The device according to claim 1, characterized in that The action execution unit executes a posture reproduction program, the posture reproduction program including a positioning command for causing the robot to operate and position the welding gun to a position different from the taught position specified in the welding operation program and the taught posture, and on the other hand, does not include a welding command for starting the welding gun to weld a workpiece, and the action execution unit positions the welding gun to the different position and the taught posture by the robot by executing the posture reproduction program, The pressure obtaining unit obtains the pressure when the operation executing unit positions the welding gun to the different position and the teaching posture.

4. The device according to claim 3, characterized in that The device also has: a posture extraction unit that extracts the teaching posture from the welding work program; and A program generating unit generates the posture reproduction program based on the teaching posture extracted by the posture extracting unit.

5. The device according to claim 4, characterized in that The device further comprises: an input receiving unit that receives input from the different positions; The program generation unit further generates the gesture reproduction program based on the different positions received by the input reception unit.

6. The device according to claim 4, characterized in that The device further comprises: an input receiving unit that receives an input of an allowable motion range of the robot when executing the posture reproduction program; The program generation unit further generates the gesture reproduction program based on the allowable motion range received by the input reception unit.

7. The device according to any one of claims 1 to 6, characterized in that: The pressure obtaining unit obtains the first pressure when the operation executing unit positions the welding gun to the first teaching posture. The command correction unit obtains a correction amount for correcting the first pressure command for driving the welding gun in the first teaching posture to the second pressure command based on the first pressure. The device also has: a posture difference calculation unit for calculating a difference between a second teaching posture and the first teaching posture; and a difference determination unit for determining whether the difference obtained by the posture difference calculation unit is smaller than a predetermined threshold value, When the difference determination unit determines that the difference is smaller than the threshold value, the action execution unit does not execute the action of positioning the welding gun to the second teaching posture. The command correction unit corrects the first pressure command for driving the welding gun in the second teaching posture using the correction amount obtained in the first teaching posture, thereby obtaining the second pressure command in the second teaching posture.

8. The device according to any one of claims 1 to 6, characterized in that: The welding operation procedure specifies a first teaching position and a first teaching posture, a second teaching position and a second teaching posture for positioning the welding gun. The pressure obtaining unit obtains the first pressure when the operation executing unit positions the welding gun to the first teaching position and the first teaching posture. The command correction unit corrects the first pressure command based on the first pressure, thereby obtaining the second pressure command at the first teaching position and the first teaching posture, and estimates the second pressure command at the second teaching position and the second teaching posture based on the obtained second pressure command and the first teaching position and the second teaching position specified in the welding operation procedure. The operation execution unit does not execute the operation of positioning the welding gun to the second teaching posture.

9. The device according to any one of claims 1 to 8, characterized in that The pressurizing force acquisition unit acquires the pressurizing force measured by the pressurizing force sensor when the welding gun positioned in the teaching posture by the operation execution unit is driven by the first pressurizing force command.

10. The device according to any one of claims 1 to 8, characterized in that: The welding gun has a movable welding nozzle and a position sensor for detecting the position of the movable welding nozzle. The device further comprises: a position acquisition unit that acquires a first position detected by the position sensor when the welding gun positioned in a predetermined reference posture is driven by the first pressure command to pressurize the object to be pressurized by the movable welding nozzle, and a second position detected by the position sensor when the welding gun positioned in the teaching posture by the action execution unit is driven by the first pressure command to pressurize the object to be pressurized by the movable welding nozzle, The pressure obtaining unit obtains the pressure in the teaching posture through a predetermined calculation based on the first position and the second position obtained by the position obtaining unit.

11. A robot control device, characterized in that: A device according to any one of claims 1 to 10.

12. A method for correcting a pressure command according to a posture of a welding gun, wherein the pressure command specifies the pressure of the welding gun when a robot moves and pressurizes a workpiece for welding, characterized in that: The processor performs the following processing: causing the robot to move so as to position the welding gun in a taught posture specified by a welding operation program for causing the robot and the welding gun to perform a welding operation; obtaining the pressure when the welding gun is driven by a first pressure command when the welding gun is positioned in the teaching posture; as well as The first pressing force command is corrected based on the acquired pressing force, thereby obtaining a second pressing force command when the welding gun is driven in the taught posture when the welding work program is executed.

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