Robotic systems, methods, and computer programs for scraping and grinding processes

Abstract

A technology is sought to perform high-quality scraping by means of a robot. The robot system (10) includes: a robot (12) that moves a scraper (16) that scrapes the surface of a workpiece; and a control device (18) that controls the robot (12). The control device (18) moves the scraper (16) in the direction along the surface of the workpiece and in the direction toward the surface by means of the robot (12), thereby causing the scraper (16) to come into contact with the surface along a trajectory that is inclined at an acute angle relative to the surface. During the period when the scraper (16) comes into contact with the surface, while controlling the position of the robot (12) in a way that the pressing force of the scraper (16) pressing the surface by the robot (12) is predetermined, the scraper (16) is moved in the direction along the surface by means of the robot (12), thereby performing scraping.

Description

Technical Field

[0001] This invention relates to a robotic system, method, and computer program for scraping and grinding. Background Technology

[0002] A robot for scraping and grinding is known (e.g., Patent Document 1).

[0003] Existing technical documents

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2004-042164 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] We are seeking a technology that uses robots to perform high-quality scraping processes.

[0008] Solution for solving the problem

[0009] In one aspect of this disclosure, a robotic system for scraping a surface to make it flattened includes: a robot that moves a scraper for scraping the surface; and a control device that controls the robot, wherein the control device moves the scraper in a direction along the surface and towards the surface simultaneously via the robot, thereby causing the scraper to come into contact with the surface along a trajectory inclined at an acute angle relative to the surface. During the contact of the scraper with the surface, while controlling the position of the robot in a manner that allows the robot to press the scraper against the surface at a predetermined magnitude, the scraper is moved in a direction along the surface via the robot, thereby performing the scraping process.

[0010] In other aspects of this disclosure, a scraping process is performed by using a robot that moves a scraper to scrape the surface of a workpiece. In this method, the scraper is moved by the robot in a direction along the surface and towards the surface, thereby causing the scraper to come into contact with the surface along a trajectory that is inclined at an acute angle relative to the surface. During the contact of the scraper with the surface, the position of the robot is controlled in a way that the robot presses the scraper against the surface with a predetermined pressure, while the scraper is moved by the robot in a direction along the surface, thereby performing the scraping process.

[0011] The effects of the invention

[0012] According to this disclosure, scraping can be performed by a robot with the same quality as when the scraping is performed by a skilled person. Attached Figure Description

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

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

[0015] Figure 3 It is from Figure 1 Observe the direction of arrow B in the image. Figure 1 An enlarged view of the scraper shown.

[0016] Figure 4 It is from Figure 3 Observe the direction of arrow D in the middle. Figure 3 An enlarged view of the scraper shown.

[0017] Figure 5 Showing Figure 1 The scraper shown is pressing against the surface of the workpiece.

[0018] Figure 6 An example of a teaching point set for the surface of a workpiece is shown.

[0019] Figure 7 This is a diagram used to illustrate the speed command as a position control command and the speed command as a force control command.

[0020] Figure 8 This shows the actual movement trajectory of the scraper during the scraping process.

[0021] Figure 9 The state of the scraper shank during scraping is schematically shown.

[0022] Figure 10 The diagram illustrates a recess formed by scraping.

[0023] Figure 11 The diagram illustrates a recess formed by scraping.

[0024] Figure 12 This demonstrates the characteristics of the pressing force applied by the scraper to the surface of the workpiece during scraping by a skilled operator, as a function of time.

[0025] Figure 13 Shown in Figure 1 The robot system shown illustrates the characteristics of the pressure applied by the robot to the surface of the workpiece during scraping, as the pressure varies over time.

[0026] Figure 14 Show Figure 1 The diagram shows an example of the motion flow of a robot system.

[0027] Figure 15 Show Figure 14 An example of the process in step S5.

[0028] Figure 16 Shown in Figure 1 Other examples of the time-varying characteristics of the pressing force of the robot system as it performs scraping when the robot presses the scraper against the surface of the workpiece.

[0029] Figure 17 Other examples of teaching points set for the surface of a workpiece are shown.

[0030] Figure 18 Show Figure 14 Other examples of the process in step S5.

[0031] Figure 19 This shows the actual movement trajectory of the scraper during the scraping process.

[0032] Figure 20 Shown in Figure 1 Another example of the time-varying characteristics of the pressing force of the robot system as it performs scraping when the robot presses the scraper against the surface of the workpiece.

[0033] Figure 21 This shows the actual movement trajectory of the scraper when performing scraping on a relatively thin workpiece.

[0034] Figure 22 Shown in the Figure 21 The characteristics of the pressure applied by the robot to the surface of the workpiece during scraping are shown, and how this pressure changes over time.

[0035] Figure 23 Shown in the Figure 21 The characteristics of the pressure applied by the robot to the surface of the workpiece during scraping are shown, and how this pressure changes over time.

[0036] Figure 24 This shows the actual movement trajectory of the scraper when performing scraping on a relatively thin workpiece.

[0037] Figure 25 Shown in the Figure 24 The characteristics of the pressure applied by the robot to the surface of the workpiece during scraping are shown, and how this pressure changes over time.

[0038] Figure 26Another example of a teaching point set for the surface of a workpiece is shown. Detailed Implementation

[0039] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. Furthermore, in the various embodiments described below, the same reference numerals will be used to refer to the same elements, and repeated descriptions will be omitted. Additionally, in the following description, the positive x-axis direction of the robot coordinate system C1 in the figures will sometimes be referred to as the right, the positive y-axis direction as the front, and the positive z-axis direction as the top.

[0040] First, refer to Figure 1 The following describes a robot system 10 according to one embodiment. The robot system 10 is a system for scraping a workpiece surface to make it flat. Scraping refers to the process of scraping a workpiece surface so that the size of the tiny bumps and depressions formed on the surface of the workpiece is within a predetermined range (e.g., on the order of μm) in the thickness direction of the workpiece.

[0041] These tiny bumps and depressions function as so-called "oil reservoirs" for accumulating lubricating oil. Here, scraping includes roughing to reduce the tiny bumps and depressions formed when the surface of the workpiece is machined by a milling cutter or the like to a first size (e.g., 10 μm or less), and finishing to reduce the tiny bumps and depressions to a second size (e.g., 5 μm or less) smaller than the first size after the roughing.

[0042] The robot system 10 includes a robot 12, a force sensor 14, a scraper 16, and a control device 18. In this embodiment, the robot 12 is a vertical joint robot, having a robot base 20, a rotating body 22, a lower arm 24, an upper arm 26, and a wrist 28. The robot base 20 is fixed to the floor of the work area. The rotating body 22 is mounted on the robot base 20 in a manner that allows it to rotate about a vertical axis.

[0043] The lower arm portion 24 is rotatably disposed on the rotating body 22, and the upper arm portion 26 is rotatably disposed on the front end of the lower arm portion 24. The wrist portion 28 has a wrist base 28a rotatably disposed on the front end of the upper arm portion 26, and a wrist flange 28b rotatably disposed on the wrist base 28a about a wrist axis A1. In this embodiment, the wrist flange 28b constitutes the front end of the hand of the robot 12.

[0044] Servo motors 34 are installed in each of the components of robot 12 (robot base 20, rotating body 22, lower arm 24, upper arm 26, wrist 28). Figure 2These servo motors 34, according to instructions from the control unit 18, cause the various movable elements of the robot 12 (rotating body 22, lower arm 24, upper arm 26, wrist 28, and hand tip 28b) to rotate around the drive shaft. As a result, the robot 12 is able to move the scraper 16 and configure it to any position and posture.

[0045] Force sensor 14 detects the pressing force F exerted by the robot 12 causing the scraper 16 to press against the surface of the workpiece. For example, force sensor 14 is a six-axis force sensor having a cylindrical main body and a plurality of strain gauges disposed on the main body, and force sensor 14 is inserted between the forehand end 28b and the scraper 16. In this embodiment, force sensor 14 is configured such that its central axis coincides with the wrist axis A1.

[0046] A scraper 16 is fixed to the front end of a force sensor 14 and scrapes the surface of a workpiece for scraping. Specifically, the scraper 16 has a flexible shank 30 and a cutting edge 32 fixed to the front end of the shank 30. The base end of the shank 30 is fixed to the front end of the force sensor 14, thereby connecting the shank 30 to the front end 28b of the hand of the robot 12 via the force sensor 14. The shank 30 extends linearly along axis A2 from the front end of the force sensor 14. The cutting edge 32 extends along axis A2 from its base end 32b to its front end 32a. Furthermore, axis A2 may be substantially orthogonal to the wrist axis A1.

[0047] like Figure 3 As shown, from the top side ( Figure 1 When observing the tip 32a of the blade 32 (in the direction of arrow B), the tip 32a of the blade 32 curves outward as it moves from both ends toward the center in its width direction. Additionally, as... Figure 4 As shown, from the front side ( Figure 3 When observing the tip 32a of the cutting edge 32 (in the direction of arrow D), the tip 32a of the cutting edge 32 has a generally rectangular shape. The scraper 16 presses the tip 32a of the cutting edge 32 onto the surface of the workpiece and scrapes the surface through the tip 32a.

[0048] The control device 18 controls the movements of the robot 12. Specifically, the control device 18 is a computer having a processor 40, a memory 42, an I / O interface 44, an input device 46, and a display device 48. The processor 40 is communicatively connected to the memory 42, the I / O interface 44, the input device 46, and the display device 48 via a bus 50. The processor 40 communicates with these components and performs calculations for executing the scraping process.

[0049] The memory 42 includes RAM or ROM, etc., for temporary or permanent storage of various data. The I / O interface 44 includes, for example, an Ethernet port, a USB port, a fiber optic connector, or an HDMI terminal, for wired or wireless communication with external devices based on instructions from the processor 40. In this embodiment, the force sensor 14 and each servo motor 34 of the robot 12 are connected to the I / O interface 44 in a manner enabling communication.

[0050] Input device 46 includes a keyboard, mouse, or touch panel for accepting data input from the operator. Display device 48 includes a liquid crystal display or organic EL display for displaying various data in a visually verifiable manner based on instructions from processor 40. Furthermore, input device 46 or display device 48 can be integrally assembled into the housing of control device 18, or it can be separately disposed outside the housing of control device 18.

[0051] like Figure 1 As shown, a robot coordinate system C1 is established for robot 12. Robot coordinate system C1 is a coordinate system used to control the movements of each movable element of robot 12, and it is fixed relative to robot base 20. In this embodiment, robot coordinate system C1 is set for robot 12 with its origin located at the center of robot base 20, and its z-axis aligned with the rotation axis of rotating body 22.

[0052] On the other hand, a tool coordinate system C2 is established for the scraper 16. The tool coordinate system C2 is a coordinate system used to define the position and posture of the scraper 16 (or the hand tip 28b) in the robot coordinate system C1. In this embodiment, the tool coordinate system C2 is set for the scraper 16 with its origin (so-called TCP) located at the center of the front end 32a of the cutting edge 32 in a state where the shank 30 is not deflected, and its z-axis parallel to the axis A2 (or the normal direction of the curved surface of the front end 32a at the center of the front end 32a).

[0053] When the scraper 16 is moved, the processor 40 of the control device 18 sets the tool coordinate system C2 in the robot coordinate system C1, and generates instructions for each servo motor 34 of the robot 12 in such a way that the scraper 16 is configured to a position and posture represented by the set tool coordinate system C2. In this way, the processor 40 can position the scraper 16 to any position and posture in the robot coordinate system C1.

[0054] On the other hand, a sensor coordinate system C3 is set for the force sensor 14. The sensor coordinate system C3 is a coordinate system used to define the direction of the force acting on the force sensor 14. In this embodiment, the sensor coordinate system C3 is set for the force sensor 14 with its origin located at the center of the force sensor 14 and its z-axis aligned with the wrist axis A1 (or its x-axis parallel to the z-axis of the tool coordinate system C2).

[0055] Figure 5 The diagram shows the state in which the robot 12 brings the tip 32a of the blade 32 of the scraper 16 against the surface Q1 of the workpiece W1. When the robot 12 presses the tip 32a of the scraper 16 against the surface Q1 in a direction orthogonal to the surface Q1 with a pressing force F, the reaction force F' of the pressing force F is applied from the surface Q1 to the force sensor 14 via the scraper 16.

[0056] Each strain gauge of the force sensor 14 sends detection data corresponding to the force acting on the force sensor 14 at this time to the control device 18. The processor 40 calculates the force f acting on the force sensor 14 at this time in the x-axis, y-axis, and z-axis directions of the sensor coordinate system C3, and the torque τ around the x-axis, y-axis, and z-axis directions, based on the detection data received from the force sensor 14 through the I / O interface 44. The processor 40 calculates the magnitude of the reaction force F' acting on the tip 32a of the cutting edge 32 in a direction orthogonal to the surface Q1 based on the force f, the torque τ, and the current state data CD of the scraper 16.

[0057] The state data CD includes, for example, at least one of the following: the angle θ1 between axis A2 and surface Q1; the distance d from wrist axis A1 (or the origin of sensor coordinate system C3) to the tip 32a of blade 32; data representing the position and orientation of tool coordinate system C2 (or sensor coordinate system C3) in robot coordinate system C1; and deflection data of handle 30 (e.g., deflection amount or elastic modulus of handle 30). In this way, force sensor 14 detects the reaction force F' as pressing force F, and control device 18 can determine the magnitude of pressing force F (reaction force F') based on the detection data of force sensor 14.

[0058] Next, refer to Figures 6-8 The scraping process performed by the robot system 10 will be explained below. For example... Figure 6 As shown, multiple teaching points TP1, TP2, TP3 and TP4 are pre-set along the surface Q1 of the workpiece W1 to position the front end 32a (that is, TCP) of the scraper 16 to perform scraping.

[0059] In this embodiment, teach point TP2 is positioned to the lower right relative to teach point TP1, and teach point TP3 is positioned to the right of teach point TP2. The positions of teach points TP2 and TP3 along the z-axis of the robot coordinate system C1 are approximately the same. Additionally, teach point TP4 is positioned to the upper right relative to teach point TP3. These teach points TP... n (n = 1, 2, 3, 4) are represented as coordinates in robot coordinate system C1 and specified in the computer program CP used to make robot 12 perform actions.

[0060] During the scraping process, the processor 40 begins position control. Specifically, after initiating position control, the processor 40 generates parameters for the robot 12 to move the scraper 16 to multiple teach points TP. n Position control instructions PC are sequentially moved. Specifically, processor 40 generates position control instructions PC to move the front end 32a of scraper 16 from teach point TP. n To the teaching point TP n+1 Position control command PC for movement n .

[0061] Processor 40, via the position control instruction PC n The servo motors 34 of the robot 12 are activated to position the scraper 16 according to the teaching points TP1→TP2→TP3→TP4. Through this position control, the processor 40 directs the scraper 16 (specifically, the front end 32a) along the path defined by the multiple teaching points TP1→TP2→TP3→TP4. n The specified movement path MP moves.

[0062] Furthermore, in this embodiment, for ease of understanding, it is assumed that the surface Q1 of workpiece W1 is approximately parallel to the xy plane of robot coordinate system C1, and the direction MD of the movement path MP is approximately parallel to the xz plane of robot coordinate system C1. Position control command PC n It has a function to specify that the scraper 16 (that is, the hand tip 28b of the robot 12) is moved from the teach point TP n Move to teaching point TP n+1 The speed V at that time P_n Speed ​​Command PC V_n (First speed command)

[0063] After position control begins, when scraper 16 reaches... Figure 6When the teach point TP2 is reached, the processor 40 begins force control. Furthermore, in this embodiment, the teach point TP2 is set such that when the front end 32a of the scraper 16 is positioned at the teach point TP2, the front end 32a separates upwards relative to the surface Q1. After force control begins, the processor 40 controls the pressing force F, which is the force F by which the robot 12 presses the scraper 16 against the surface Q1 of the workpiece W1, to a target value F based on the detection data from the force sensor 14. T The position of the hand front end 28b (or TCP) of robot 12 is controlled in this way.

[0064] Specifically, in force control, the processor 40 controls the pressing force F (specifically, the reaction force F') obtained based on the detection data from the force sensor 14 to a target value F. T The processor 40 then generates force control instructions FC for controlling the position of the hand tip 28b (TCP) of robot 12. The processor 40 then executes position control instructions PC. n The force control command FC is added to make the servo motor 34 of robot 12 move.

[0065] Therefore, the processor 40 follows the position control instruction PC. n Simultaneously, the scraper 16 (or the handpiece 28b) is moved in the direction MD, and the scraper 16 is moved in the direction of approaching or separating from the surface Q1 of the workpiece W1 (i.e., the z-axis direction of the robot coordinate system C1) according to the force control command FC. The force control command FC has a speed command FC for specifying the speed at which the scraper 16 moves in the z-axis direction of the robot coordinate system C1. V (Second speed command)

[0066] When the scraper 16 reaches the teach point TP2, the processor 40 generates the speed instruction PC. V_2 PC2 serves as the position control command for moving the scraper 16 from teach point TP2 to teach point TP3, and generates the speed command FC. V_0 As a force control command (FC). Figure 7 The diagram schematically illustrates the speed instruction PC generated by the processor 40 when the scraper 16 reaches the teach point TP2. V_2 and speed command FC V_0 .

[0067] After the scraper 16 reaches the teach point TP2, the processor 40 executes the speed command PC. V_2 The robot 12 is made to move, causing the scraper 16 to move from the teach pendant TP2 to the teach pendant TP3 in accordance with the speed command PC. V_2 The corresponding (specifically, the same) velocity V P_2 Move in the direction MD.

[0068] At the same time, processor 40 generates speed instruction FC V_0 And in the speed command PC for servo motor 34 V_2 Add this speed command to FC V_0 This causes the scraper 16 to move in the direction of the surface Q1 (i.e., downwards) in accordance with the speed command FC. V_0 The corresponding speed V F_0 Movement. As a result, robot 12 causes scraper 16 to move after passing teach point TP2. Figure 7 Move in the direction MD'.

[0069] Figure 8 The solid line in the figure shows the actual trajectory TR of the scraper 16 (specifically, the front end 32a) during the scraping process. After passing the teaching point TP2, the scraper 16 moves toward surface Q1 along the trajectory TR, which is inclined at an acute angle θ2 relative to surface Q1, and abuts against surface Q1 at position P1. During the period when the scraper 16 abuts against surface Q1, the processor 40 generates a speed command FC while moving the scraper 16 in the direction MD (i.e., to the right) along surface Q1 according to the position control command PC2. V_1 As a means of controlling the pressing force F to a target value F through force control. T Force control command FC.

[0070] Through this speed command FC V_1 The position of the hand tip 28b of robot 12 is aligned with the z-axis of robot coordinate system C1, in accordance with the velocity command FC. V_1 The corresponding speed V F_1 Displacement. Here, the velocity command FC generated during the period when the scraper 16 abuts against surface Q1. V_1 (i.e., velocity V) F_1 The maximum value can be set to be higher than the speed command FC generated before the scraper 16 comes into contact with surface Q1. V_0 (i.e., velocity V) F_0 )big.

[0071] Thus, the scraper 16 is subjected to a target value F. T A corresponding pressing force F is applied, pressing one side and moving it to the right along surface Q1, thereby performing a scraping process on surface Q1 by scraping through the front end 32a of scraper 16. Figure 9 The image shows the state of the scraper 16 during the scraping process. For example... Figure 9 As shown, during the scraping process, the robot 12 presses the front end 32a of the scraper 16 against the surface Q1 with a pressing force F, thereby causing the shank 30 of the scraper 16 to bend and flex downwards. In other words, the target value F of the force control...T The value is set to cause the shank 30 to flex during scraping.

[0072] Refer again Figure 8 When the scraper 16 (or the hand tip 28b) reaches the position corresponding to the teach point TP3, the processor 40 generates a position control command PC3 to move the scraper 16 toward the teach point TP4. The processor 40 moves the hand tip 28b to the upper right by inducing the robot 12 to move according to the position control command PC3. As a result, the scraper 16 moves to the upper right along a trajectory TR that is inclined at an acute angle θ3 relative to the surface Q1 of the workpiece W1, and the tip 32a of the scraper 16 leaves the surface Q1 at position P2. Thus, the scraping process is completed.

[0073] By performing scraping processes in this way, such as Figure 10 and Figure 11 As shown, on surface Q1, a curved recess R is formed extending to the right from position P1 to position P2. Figure 10 and Figure 11 In the example shown, the recess R has a length x2 along the x-axis and a depth E along the z-axis in the robot coordinate system C1. Furthermore, in Figure 10 and Figure 11 In the illustration, the depth E of the recess R is magnified for ease of understanding, but it is important to understand that the actual depth E of the recess R is less than 10 μm.

[0074] In this embodiment, the processor 40 generates the speed command PC in a manner that ensures the acute angle θ2 is within a predetermined range. V_2 and speed command FC V_0 Here, the inventors of the present invention obtained the insight that a skilled scraper 16 moves along a trajectory at an angle of 15° to 35° relative to the surface Q1 of the workpiece W1 to come into contact with the surface Q1.

[0075] Furthermore, the inventors of this invention have obtained a pressing force F that allows the cutting edge 32 of the scraper 16 to press against the surface Q1 of the workpiece W1 during continuous scraping operations performed by a skilled operator. R Data on the characteristics that change over time. In Figure 12 The diagram illustrates this characteristic as it changes over time. According to... Figure 12 The time-varying characteristics shown indicate that the inventors of this invention obtained the pressing force F of a skilled worker pressing the cutting edge 32 against the surface Q1 during a single scraping process (that is, forming a recess R). R The size (peak value of the characteristic that changes over time) was determined, and it was found that a skilled worker moved the blade 32 at a speed of approximately 100 mm / sec during scraping.

[0076] Here, when Figure 8 When the distances between the teaching point TP2 and position P1 in the robot coordinate system C1 along the x-axis and z-axis are set as distance x1 and distance z1 respectively, and the velocity command PC is... V_2 (speed V) P_2 ) and speed command FC V_0 (speed V) F_0 It satisfies the following equation (1).

[0077] z1 / x1=FC V_0 / PC V_2 =V F_0 / V P_2 ···(1)

[0078] Additionally, acute angle θ2, distance x1 and distance z1, and velocity command PC. V_2 (speed V) P_2 ) and speed command FC V_0 (speed V) F_0 It satisfies the following equation (2).

[0079] θ2=tan ﹣1 (z1 / x1)=tan ﹣1 (FC V_0 / PC V_2 ) = tan ﹣1 (V F_0 / V P_2 (2)

[0080] Therefore, when assuming x1 = 10 mm and z1 = 5 mm as the processing condition MC for scraping, equation (2) can determine that the acute angle θ2 ≈ 26.6°. In this case, the speed V is set as the processing condition MC. P_2 (i.e., speed command PC) V_2 When the speed is set to 100 [mm / sec], the same as the moving speed of the scraper 16 moved by the skilled operator described above, the speed V can be adjusted using equation (1). F_0 (i.e., speed command FC) V_0 The value is determined to be 50 [mm / sec].

[0081] Instead, with θ2 = 25° and speed command PC... V_2 (speed V) P_2 When MC is the processing condition 100 [mm / sec], it can be determined as FC by equation (2). V_0 (speed V) F_0)≈46.6[mm / sec]. In this case, when z1 is set to 10[mm], x1≈21.4[mm] can be determined by equation (1).

[0082] In addition, the target value F is used as the processing condition MC. T The values ​​are set to correspond to the material of the workpiece W1 and the target depth E of the recess R (e.g., 100 [N]). Thus, the machining conditions MC include distance x1, distance z1, acute angle θ2, and speed V. F_0 (Speed ​​Command FC) V_0 and velocity V P_2 (Speed ​​Command PC) V_2 ).

[0083] The inventors of this invention, through observation and dedicated study of scraping processes performed by skilled workers, discovered that if the processing conditions MC are appropriately set, the aforementioned acute angle θ2 can be controlled within a range of, for example, 15° to 35°, and the time-varying characteristics of the pressing pressure F can be made consistent with... Figure 12 The pressing pressure F is controlled in the same way as the characteristics that change over time, thereby enabling the robot 12 to perform scraping with the same quality as when a skilled person performs scraping.

[0084] Figure 13 The diagram illustrates the time-varying characteristics of the pressing force F, which causes the cutting edge 32 of the scraper 16 to press against the surface Q1 of the workpiece W1, when the processor 40 causes the robot 12 to move according to the specified processing conditions MC to continuously perform scraping (that is, to form multiple recesses R). Figure 13 As shown, by having the robot 12 perform scraping processing according to appropriately set processing conditions MC, the pressing pressure F in a single scraping process can be controlled to be the same as that in a single scraping process. Figure 12 The magnitude of similar properties that change over time.

[0085] The following reference Figure 8 and Figure 13 The variation of the pressing force F over time during the scraping process performed by robot 12 will be explained in detail. After the front end 32a of scraper 16 abuts against the surface Q1 of workpiece W1 at position P1, processor 40 generates a force control command FC (speed command FC). V_1 ), so that the position of the front end 28b of the robot 12's hand is at a speed V F_1 The material shifts downwards, causing the pressing force F to increase sharply.

[0086] On the other hand, processor 40 generates position control instruction PC2 (speed instruction PC) for moving scraper 16 from teach point TP2 to teach point TP3 as described above. V_2However, as the teach point TP3 approaches, the position control command PC2 becomes more dominant than the force control command FC. The processor 40 causes the scraper 16 (hand tip 28b) to move in the direction away from the surface Q1 of the workpiece W1 (i.e., upwards) before reaching the position corresponding to the teach point TP3. As a result, the magnitude of the pressing force F becomes... Figure 13 The peak value F shown P It then decreased sharply.

[0087] In this embodiment, the distance x3 between teach point TP2 and teach point TP3 in the x-axis direction of the robot coordinate system C1 is set to be relatively short in order to make the length x2 of the recess R formed by scraping relatively short. In this case, the processor 40 achieves the target value F of force control when the pressing pressure F reaches the target value F. T Previously, the scraper 16 was moved upwards. Therefore, in this embodiment, the peak value F... P Become more than the target value F T Small.

[0088] Subsequently, the processor 40 moves the robot 12 according to position control commands PC2 and PC3, causing the scraper 16 to move upward and to the right along a trajectory TR inclined at an acute angle θ3. At the moment when the scraper 16 leaves the surface Q1 at position P2, the pressing pressure F becomes zero. In this way, the processor 40 controls the pressing pressure F during the scraping process as... Figure 13 The size of the property shown is predetermined.

[0089] Furthermore, the "predetermined magnitude" of the pressing pressure F includes not only the peak value F. P , also includes Figure 13 The characteristics shown vary over time. Furthermore, as described above, in this embodiment, the peak value F of the pressing pressure F... P The target value F becomes more controllable T Small. The peak value F P With the target value F T Correspondingly, it depends on the target value F T And change. In other words, the peak F P Able to pass the target value F T It is under control.

[0090] Next, refer to Figure 14 Here is an example illustrating the motion flow of the robot system 10. The processor 40 executes the computer program CP pre-stored in the memory 42. Figure 14 The process is shown below. Figure 14 The process shown begins, for example, when control device 18 is started.

[0091] In step S1, the processor 40 determines whether the processing condition MC has been received as input. For example, the processor 40 generates the distance x1, distance z1, acute angle θ2, and velocity V mentioned above as inputs for the processing condition MC. F_0 (Speed ​​Command FC) V_0 ), speed V P_2 (Speed ​​Command PC) V_2 and the target value F T The input screen contains image data, and the display device 48 of the control device 18 displays the image data.

[0092] While visually confirming the input screen displayed on the display device 48, the operator operates the input device 46 of the control device 18 to input the distance x1, distance z1, acute angle θ2, and speed V as processing conditions MC. F_0 (Speed ​​Command FC) V_0 and velocity V P_2 (Speed ​​Command PC) V_2 At least three data points from the input, and input the target value F as the processing condition MC. T If the processor 40 receives input data of the processing condition MC from the input device 46, it determines "yes" and proceeds to step S2. On the other hand, if it does not receive input data of the processing condition MC, it determines "no" and proceeds to step S3.

[0093] In step S2, the processor 40 determines the processing conditions MC. For example, suppose the operator inputs the processing conditions MC as x1 = 10 [mm], z1 = 5 [mm], and V in step S1. P_2 (PC V_2 =100 [mm / sec]. In this case, the processor 40 automatically determines θ2 = 26.6° and V based on the input data of the processing condition MC and the above equations (1) and (2). F_0 (FC V_0 =50 [mm / sec] as the processing condition MC.

[0094] In this embodiment, the processor 40 automatically determines other parameters in the processing conditions MC based on a subset of parameters received from the operator. Then, the processor 40 assigns these parameters x1 = 10 [mm], z1 = 5 [mm], and V... P_2 (PC V_2 )=100[mm / sec], θ2=26.6°, V F_0 (FC V_0 = 50 [mm / sec], and target value F T Set as processing condition MC.

[0095] In step S3, the processor 40 determines whether a scraping start command has been received from the operator, the upper controller, or the computer CP. If the scraping start command has been received, the processor 40 determines "yes" and proceeds to step S4; otherwise, if the scraping start command has not been received, it determines "no" and proceeds to step S6.

[0096] In step S4, the processor 40 determines whether all processing conditions MC have been set. Specifically, the processor 40 sets the distance x1, distance z1, acute angle θ2, and velocity V as processing conditions MC. F_0 (Speed ​​Command FC) V_0 and velocity V P_2 (Speed ​​Command PC) V_2 If all settings are completed, the system determines "Yes" and proceeds to step S5. Meanwhile, the processor 40 sets the distance x1, distance z1, acute angle θ2, and velocity V as processing conditions MC. F_0 (Speed ​​Command FC) V_0 and velocity V P_2 (Speed ​​Command PC) V_2 If at least one of the options is not specified, the result is determined to be "No", and the process proceeds to step S7.

[0097] In step S5, the processor 40 performs a scraping process. For step S5, refer to... Figure 15 To illustrate, in step S11, the processor 40 begins position control. Specifically, the processor 40 begins generating the aforementioned position control instruction PC. n The robot 12 moves the front end 32a of the scraper 16 in the order of teaching points TP1→TP2→TP3→TP4.

[0098] In step S12, the processor 40 determines whether the scraper 16 has reached the teaching point TP2. For example, the servo motor 34 of the robot 12 is equipped with a rotation detector (encoder or Hall element, etc.) to detect the rotation of the servo motor 34 (specifically, the rotation angle or rotation position).

[0099] The processor 40 acquires the position data of the scraper 16 (specifically, TCP) in the robot coordinate system C1 based on feedback from the rotation detector, and can determine whether the scraper 16 has reached the teaching point TP2 based on the position data. If the processor 40 determines that the scraper 16 has reached the teaching point TP2 (i.e., "yes"), it proceeds to step S13; otherwise, if the processor 40 determines that the scraper 16 has not reached the teaching point TP2 (i.e., "no"), it loops through step S12.

[0100] In step S13, the processor 40 begins force control. Specifically, the processor 40 begins the action of generating the aforementioned force control instruction FC, while the position control instruction PC... n A force control command FC is added to make the robot 12 perform actions. Here, in step S2 above, the speed command PC is set. V_2 =100 [mm / sec] and speed command FC V_0 =50 [mm / sec] as the processing condition MC.

[0101] Therefore, processor 40 generates speed instructions PC V_2 =100 [mm / sec] is used as the position control command PC2, and the speed command FC is generated. V_0 =50 [mm / sec] as the force control command FC. This speed command PC... V_2 and speed command FC V_0 To enable the robot 12 to perform actions, the processor 40 causes the scraper 16 to move at a speed V. P_2 =100 [mm / sec] moving in direction MD while at a speed of V F_0 =50 [mm / sec] moving downwards. As a result, the scraper 16 moves along a trajectory TR inclined at an acute angle θ2≈26.6°. Figure 8 The object moves toward surface Q1 of workpiece W1. In this way, the acute angle θ2 can be controlled within a specified range (e.g., 15° to 35°).

[0102] In step S14, the processor 40 determines whether the pressing force F obtained based on the detection data of the force sensor 14 has changed to a predetermined threshold F. th Above (F≥F th The threshold F th The value Q1, representing the contact between the front end 32a of the scraper 16 and the surface of the workpiece W1, is predetermined by the operator. The processor 40 then changes to F≥F. th In the case of F < F, the result is determined to be "yes" and proceeds to step S15. On the other hand, in the case of F < F th If the condition is "no", then the process repeats step S14.

[0103] In step S15, the processor 40 switches the force control instruction FC. Specifically, the processor 40 switches the force control instruction FC to be generated from the speed instruction FC. V_0 Switch to speed command FC V_1 When switching to speed command FC V_1 Then, processor 40 generates the speed instruction FC. V_1 And in order to control the pressing force F to the target value F TThe position of the forehand end 28b of robot 12 is aligned with the z-axis of robot coordinate system C1, so as to match the speed command FC. V_1 The corresponding speed V F_1 Displacement. As mentioned above, velocity V F_1 (Speed ​​Command FC) V_1 The maximum value of ) can become greater than the velocity V. F_0 (Speed ​​Command FC) V_0 )big.

[0104] In step S16, the processor 40 determines whether the scraper 16 (or the front end 28b) has reached the position corresponding to the teach point TP4. Here, after the start of step S13, the processor 40 executes position control and force control in parallel, so the front end 32a of the scraper 16 moves along... Figure 8 The trajectory TR shown moves and passes below teaching points TP3 and TP4.

[0105] In step S16, the processor 40 determines, based on feedback from the aforementioned rotation detector, whether the x-coordinate of the front end 32a (or the hand end 28b) in the robot coordinate system C1 is consistent with the x-coordinate of the teaching point TP4. If the determination is "yes", the processor 40 proceeds to step S17; otherwise, if the determination is "no", step S16 is repeated.

[0106] Before determining "yes" in step S16, as described above, the front end 32a of the scraper 16 leaves the surface Q1 of the workpiece W1 at position P2. Then, in step S17, the processor 40 terminates force control and position control. Thus, one scraping operation is completed, forming a layer on the surface Q1 of the workpiece W1. Figure 10 and Figure 11 The recessed portion R shown in the diagram.

[0107] Refer again Figure 14 In step S6, the processor 40 determines whether an action end command has been received from the operator, the superior controller, or the computer program CP. If an action end command has been received, the processor 40 determines "yes" and terminates the process. Figure 14 The process shown, on the other hand, determines "no" if no action end instruction is received, and returns to step S1.

[0108] On the other hand, if the determination in step S4 is "no", in step S7, the processor 40 sends a warning signal. For example, the processor 40 generates a warning signal with sound or image such as "Please set processing conditions" and outputs the warning signal to the operator through a speaker (not shown) or display device 48 provided in the control device 18. Then, the processor 40 returns to step S1.

[0109] As described above, in this embodiment, the processor 40, via the robot 12, directs the scraper 16 to abut against the surface Q1 of the workpiece W1 along a trajectory TR inclined at an acute angle θ2. Furthermore, during the contact between the scraper 16 and surface Q1, the processor 40 controls the pressing force F to a predetermined value. Figure 13 At the same time, the scraper 16 moves along the surface W S It moves to the right, thereby performing the scraping process. According to this structure, the robot 12 can perform scraping processes with the same quality as when a skilled person performs the scraping process.

[0110] Furthermore, in this embodiment, during the period when the scraper 16 abuts against the surface Q1 of the workpiece W1, the processor 40 performs force control based on the detection data of the force sensor 14, thereby controlling the position of the hand tip 28b of the robot 12 along the z-axis direction of the robot coordinate system C1. According to this structure, the pressing pressure F can be controlled with high precision during scraping. Figure 13 The size of the property shown is predetermined.

[0111] Therefore, the time-varying characteristics of the pressing force F when the robot 12 performs the scraping process can be made close to the pressing force F when the skilled operator performs the scraping process. R The time-varying characteristics of ( Figure 12 Therefore, the quality of the scraping process performed by the robot 12 can be made to more effectively approach the quality of the scraping process performed by a skilled person.

[0112] Furthermore, in this embodiment, the processor 40, according to the position control instruction PC2 (specifically, the speed instruction PC), V_2 Simultaneously, the scraper 16 moves from teach point TP2 to teach point TP3, according to the force control command FC (specifically, the speed command FC). V_0 The scraper 16 is moved downward so that it comes into contact with the surface Q1 of the workpiece W1 along a trajectory TR inclined at an acute angle θ2.

[0113] Furthermore, the processor 40 generates speed instructions PC in a manner that keeps the acute angle θ2 within a predetermined range (e.g., 15° to 35°). V_2 and speed command FC V_0 Based on this structure, it is possible to control the position via command PC2 (speed command PC). V_2 ) and force control command FC (speed command FC) V_0 This allows the acute angle θ2 of the trajectory TR to be controlled with high precision within the desired range. Consequently, the quality of the scraping process performed by the robot 12 can more effectively approach the quality of the scraping process performed by a skilled operator.

[0114] Furthermore, in this embodiment, the processor 40 presses the pressure F to reach the target value F during the force control period. T Previously, the scraping process was ended by moving the scraper 16 in a direction away from the surface Q1 of the workpiece W1 (i.e., upwards). According to this structure, the characteristics of the time-varying pressure F during a single scraping operation can be adjusted. Figure 13 Effectively approximates the pressing force F when controlled by a skilled operator. R The time-varying characteristics of ( Figure 12 In addition, it is possible to... Figure 9 As shown, the recess R is formed into a curved shape with its central portion recessed. This improves the quality of the scraping process.

[0115] Furthermore, in this embodiment, when performing scraping, the processor 40 causes the scraper 16 to leave the surface Q1 along a trajectory TR that forms an acute angle θ3 relative to the surface Q1 of the workpiece W1, thereby ending the scraping process. According to this structure, the recess R can be formed into a curved shape, thus improving the quality of the scraping process.

[0116] Furthermore, the acute angle θ3 can be controlled by adjusting the positions of teaching points TP3 and TP4, or by the angle between the movement path MP from teaching point TP2 to teaching point TP3 and the movement path MP from teaching point TP3 to teaching point TP4. As an example, the acute angle θ3 is controlled to be between 14° and 20°.

[0117] In addition, in this embodiment, such as Figure 9 As shown, the target value F for force control is determined by the manner in which the shank 30 deflects when the cutting edge 32 is pressed against the surface Q1 of the workpiece W1 during the scraping process. T (That is, the magnitude of the pressing force F). According to this structure, the minute vibrations of the cutting edge 32 generated during scraping can be absorbed by the flexure of the handle 30, and the pressing force F can be uniformly applied from the cutting edge 32 to the surface Q1. As a result, the surface of the formed recess R can be prevented from becoming wavy, thus improving the quality of the scraping process.

[0118] Furthermore, the processor 40 can also align the axis A2 of the scraper 16 with the scraper during the scraping process. Figure 7 The wrist posture is controlled in a manner parallel to the direction MD' (that is, the trajectory TR from the teaching point TP2 to the position P1) (i.e., θ1 = θ2). Alternatively, the processor 40 can also control the wrist posture in a manner that satisfies θ1 < θ2 (or θ1 > θ2) (that is, the axis A2 is not parallel to the direction MD').

[0119] In the above embodiment, the processor 40 applies pressure F to reach the target value F during the force control period.T The previous description of moving the scraper 16 upwards has been given. However, it is not limited to this; the processor 40 can also apply pressure F to achieve the target value F during force control. T The time point causes the scraper 16 to move upward. In this case, the characteristics of the time-varying pressure F are similar to... Figure 13 Similarly, on the other hand, the peak F P With the target value F T same.

[0120] As an example, the peak value F can be increased by making the distance x3 between teaching point TP2 and teaching point TP3 longer than the distance between teaching point TP2 and teaching point TP3 in the above embodiment. P With the target value F T The pressing force F is controlled in the same way. Alternatively, the processor 40 can also control the speed command FC generated during force control after the blade 32 abuts against the surface Q1 of the workpiece W1 (determined as "yes" in step S14 above). V_1 Increase to make the peak value F P With the target value F T The pressing force F is controlled in the same way.

[0121] Alternatively, the processor 40 can achieve the target value F by applying a pressure F through force control. T Then, the pressing force F is maintained at the target value F. T The scraping process continues in this manner. For example, when the distance x3 between teach point TP2 and teach point TP3 is set to be long and processor 40 executes... Figure 14 and Figure 15 In the case of this process, the pressing pressure F is maintained at the target value F. T The scraping process continues in this manner.

[0122] exist Figure 16 The diagram illustrates the characteristics of the pressing force F over time during scraping. After the scraper 16 passes the teach point TP2 and abuts against the surface Q1 of the workpiece W1 at position P1, the pressing force F increases sharply, reaching the target value F. T The general consistency is maintained. Subsequently, while the processor 40 moves the scraper 16 to the right toward the teach point TP3 according to the position control instruction PC2, it maintains the pressing pressure F at the target value F. T The method generates force control commands (FC) (specifically, speed commands FC). V_1 ), to control the position of the front end 28b of the robot 12's hand.

[0123] Next, similarly to the embodiment described above, the processor 40 moves the scraper 16 upwards before it reaches the position corresponding to the teach point TP3 (specifically, the position below the teach point TP3). As a result, the pressing force F decreases sharply, and the pressing force F becomes zero when the cutting edge 32 of the scraper 16 leaves the surface Q1 of the workpiece W1 at position P2.

[0124] In this way, the processor 40 controls the pressing force F during the scraping process as... Figure 16 The size is predetermined by the characteristics shown. According to this embodiment, the robot 12 can form a recess R with a relatively long length x2 to the same quality as when the scraping process is performed by a skilled person.

[0125] In addition, teaching point TP n Not limited to Figure 6 As shown, any number of teaching points can be set for workpiece W. Figure 17 The teaching point TP is shown in the middle. n Other methods. In Figure 17 In the illustrated configuration, teaching points TP1, TP2, TP3, TP4, and TP5 are set along the surface Q1 of workpiece W1. Here, teaching point TP4 is positioned to the right of teaching point TP3, and the positions of teaching points TP2, TP3, and TP4 in the z-axis direction of the robot coordinate system C1 are approximately the same. Furthermore, teaching point TP5 is positioned to the upper right of teaching point TP4.

[0126] Next, refer to Figure 14 , Figure 18 as well as Figure 19 Come to the like Figure 17 The teaching point TP is set as shown. n The operation flow of the robot system 10 under the following circumstances will be described. In this embodiment, the processor 40 also executes... Figure 14 The process shown is different from that of the above-described embodiment in step S5. Refer to the following... Figure 18 The following will explain step S5 involved in this embodiment.

[0127] After step S5 begins, similarly to the above-described embodiment, processor 40 executes steps S11 to S16. Thus, as... Figure 19 As shown, after the scraper 16 moves from the teaching point TP1 to the teaching point TP2, it moves along the trajectory TR inclined at an acute angle θ2 toward the surface Q1 of the workpiece W1 and abuts against the surface Q1 at position P1.

[0128] During the period when the scraper 16 abuts against surface Q1, while the processor 40 moves the scraper 16 in the direction MD (right) according to position control instructions PC2 and PC3, it generates a force control mechanism to control the pressing force F to the target value F. T Speed ​​Command FC V_1 . Figure 20 The diagram illustrates the time-varying characteristics of the pressing force F when the processor 40 performs force control in this embodiment. Through force control, the pressing force F increases sharply from point t1 when the scraper 16 abuts against surface Q1 at position P1.

[0129] In this embodiment, the processor 40 presses the scraper 16 at time t2 when the pressure F reaches its peak value F at the time point t2 corresponding to the teach point TP3. P Then, at time point t3 (i.e., the time point determined as "yes" in step S16) when the scraper 16 (specifically, the front end 32a) reaches the position corresponding to the teaching point TP4 (specifically, the position below the teaching point TP4), a force control command FC (specifically, a speed command FC) is generated in such a way that the pressure F becomes zero. V_1 The processor 40 controls the position of the hand tip 28b of the robot 12. Additionally, the processor 40 generates position control instructions PC3 and force control instructions FC in a manner that causes the scraper 16 to be in contact with the surface Q1 of the workpiece W1 at time t3.

[0130] Refer again Figure 18 When the determination is "yes" in step S16 (time point t3), in step S21, the processor 40 terminates force control. After step S21, the processor 40 causes the robot 12 to move according to the position control command PC4, so that the scraper 16... Figure 19 As shown, the scraper moves to the upper right along the trajectory TR inclined at an acute angle θ3. As a result, the scraper 16 leaves the surface Q1 of the workpiece W1 at position P2, and the scraping process ends.

[0131] In step S22, the processor 40 determines whether the scraper 16 has reached the position corresponding to the teach point TP5. If the determination is "yes", the processor 40 proceeds to step S23; otherwise, if the determination is "no", step S22 is repeated. Then, in step S23, the processor 40 ends the position control.

[0132] As described above, in this embodiment, the pressure F reaches its peak value at time t2 when the scraper 16 reaches the teach point TP3. P Furthermore, force control is executed at time t3 when the scraper 16 reaches the teach point TP4, in a manner that the pressure F becomes zero. Based on this structure, more detailed control is possible. Figure 20The characteristics of the pressing force F changing over time, as shown, can therefore effectively make Figure 20 The characteristics of the pressing force F over time shown are close to the pressing force F when a skilled person performs scraping. R Changes over time.

[0133] Furthermore, in the above embodiment, the processor 40 can also modify the force control command based on the thickness H of the workpiece W in the z-axis direction of the robot coordinate system C1. This function will be explained below. Figure 21 The diagram shows processor 40 pairs with a ratio Figure 8 The workpiece W1 shown is thinner than the workpiece W2 of thickness H. Figure 14 The actual trajectory TR' of the scraper 16 during the process shown. Furthermore, in Figure 21 In the middle, for comparison purposes, the lines will be represented by dashed lines. Figure 8 The workpiece W1 shown is illustrated by superimposing the trajectory TR, which is represented by a dotted line.

[0134] In addition, Figure 21 In the method shown, the teaching point TP is set as the teaching point. n (n = 1 to 4) are set in relation to Figure 8 The position in the same way as the robot's coordinate system C1. For example... Figure 21 As shown, workpiece W1 has a thickness H1 in the z-axis direction of robot coordinate system C1, while workpiece W2 has a thickness H2 (< H1) that is thinner than the thickness H1.

[0135] When the processor 40 performs scraping on the workpiece W2, the front end 32a of the scraper 16 passes through position P1 and abuts against the surface Q2 of the workpiece W2 at position P1' located to the lower right of position P1. Then, similarly to the embodiment described above, the processor 40 causes the front end 28b of the robot 12 to begin moving upward before reaching the teaching point TP3, so that the scraper 16 leaves the surface Q2 at position P2' located below position P2.

[0136] exist Figure 22 The characteristic of the pressing force F changing with time under scraping processing conditions like this is represented by a solid line. Furthermore, in... Figure 22 In order to make comparisons, the following will be used: Figure 8 The characteristics of the pressing force F during scraping of workpiece W1 as a function of time (and...) Figure 13 (Corresponding lines) are shown in an overlapping manner using dashed lines. For example... Figure 22 As shown, when scraping a thin workpiece W2, the peak value of the pressure F is... P 'Becomes more than the peak value F when scraping workpiece W1' PSmall. In this case, there is a possibility that the scraper 16 does not press sufficiently against the surface Q2 of the workpiece W2, resulting in a recess R with a depth E that does not meet the desired size.

[0137] Therefore, in this embodiment, the processor 40 modifies the speed command FC generated during force control based on the thickness H of the workpiece W. V_1 (speed V) F_1 It can be modified by changing the FC used to generate speed commands. V_1 Gain G, maximum speed V of servo motor 34 MAX Alternatively, the speed command FC can be changed using the time constant T. V_1 .

[0138] Here, speed command FC V_1 It is generated by multiplying the detection data (or pressing force F) of the force sensor 14 by the gain G, which is a parameter used to specify the response speed when the servo motor 34 is operated by force control. Additionally, the time constant T is used to specify the speed V of the servo motor 34 between zero and its maximum speed V. MAX The time required for acceleration and deceleration.

[0139] The gain G and the maximum speed V MAX The larger the value of the time constant T, or the smaller the value of the time constant T, the faster the speed command FC will be. V_1 The larger it becomes, the more it can enable... Figure 22 The gradient (differential value) of the time-varying characteristic of the pressing force F is increased. By increasing the gradient of the time-varying characteristic of the pressing force F, it is possible to make the pressing force F reach its peak value F in a shorter time during force control. P (or target value F) T ).

[0140] As an example, the memory 42 of the control device 18 pre-stores information representing the thickness H of the workpiece W, the gain G, and the maximum rotational speed V. MAX The data table DT1 shows the relationship between the time constant T and the time constant. This data table DT1 will ensure a sufficiently large peak value F during force control. P Gain G, maximum speed V MAX The time constant T is stored in relation to the thickness H. Data table DT1, for example, can be obtained through experimental methods or simulation of the cumulative gain G, maximum rotational speed V, etc. MAX It is created using a dataset of time constant T and thickness H.

[0141] On the other hand, during processor 40 execution Figure 14 Before the process shown, the operator measures the thickness H of the workpiece W. Then, the process begins in processor 40. Figure 14Following the process shown, the operator, in addition to inputting the distance x1, distance z1, acute angle θ2, and speed V as processing conditions MC, also needs to input the aforementioned parameters. F_0 (Speed ​​Command FC) V_0 ), speed V P_2 (Speed ​​Command PC) V_2 and the target value F T In addition, the thickness H of the workpiece W, which has been measured, is also input as the processing condition MC.

[0142] Therefore, processor 40 accepts the input of thickness H and determines it as "yes" in step S1. Next, in step S2, processor 40 searches data table DT1 for the gain G and maximum rotational speed V corresponding to the input thickness H. MAX and the time constant T, and the thickness H, the gain G, and the maximum rotational speed V. MAX The time constant T is set as the processing condition MC. That is, in this embodiment, the processing condition MC includes not only distance x1, distance z1, acute angle θ2, and velocity V, but also other parameters. F_0 (Speed ​​Command FC) V_0 ), speed V P_2 (Speed ​​Command PC) V_2 and the target value F T Also, thickness H, gain G, and maximum rotational speed V. MAX And the time constant T.

[0143] Then, after determining "yes" in step S14 of step S5, the processor 40 uses the gain G and maximum speed V set in step S2. MAX And a time constant T, to generate a speed command FC corresponding to the thickness H of the workpiece W. V_1 This leads to control over execution. Figure 23 The diagram shows the characteristics of the pressing force F changing over time when the action flow involved in this embodiment is performed on the workpiece W2.

[0144] like Figure 23 As shown, according to this embodiment, the speed command FC is set according to the thickness H2 of the workpiece W2. V_1 As the pressure F increases, the gradient of the change in pressure F becomes greater than Figure 22 Due to its large size, the pressing force F reaches its peak value in a short time. P Therefore, the scraper 16 can press the surface Q2 of the workpiece W2 with sufficient pressing force F, thus enabling the depth E of the recess R to reach the desired value.

[0145] Furthermore, in this embodiment, the speed change command FC is used. V_1 The parameters are illustrated, such as gain G and maximum speed V. MAXAnd the time constant T. However, it is not limited to this; it can also use FC, which can change the speed command. V_1 Any parameter. Furthermore, it is not limited to the speed change command FC. V_1 The processor 40 can also adjust the torque command for the servo motor 34 according to the thickness H of the workpiece W, so that the pressing force F can quickly reach its peak value F during force control. P .

[0146] In addition, processor 40 can also replace the speed change instruction FC. V_1 The teaching point TP3 and its position are adjusted according to the thickness H of the workpiece W to ensure a sufficiently large peak value F during force control. P See below for reference. Figure 24 To illustrate this function, the memory 42 of the control device 18 pre-stores a data table DT2 representing the relationship between the thickness H of the workpiece W and the offsets δ3 and δ4 of the teaching point TP3 and TP4. Furthermore, the offsets δ3 and δ4 can be the same or different.

[0147] In this data table DT2, a sufficiently large peak value F will be ensured during force control. P The offsets δ3 and δ4 are stored in relation to the thickness H. The data table DT2 can be created, for example, by experimental methods or by simulating a dataset of accumulated offsets δ3 and δ4 with the thickness H.

[0148] On the other hand, refer to Figure 21 and Figure 23 Similarly, as described above, the operator pre-determines the thickness H of the workpiece W, and... Figure 14 In step S1, the thickness H of the workpiece W is input as the processing condition MC. In step S2, the processor 40 searches the data table DT2 for the offsets δ3 and δ4 corresponding to the input thickness H.

[0149] Then, the processor 40 obtains the new teaching point TP3' after the predetermined teaching point TP3 has been shifted to the right by an offset amount δ3. Figure 24 The position data of the robot (specifically, the coordinates in the robot coordinate system C1) and the position data of the new teaching point TP4' after the predetermined teaching point TP4 is offset to the right by an offset amount δ4.

[0150] Then, the processor 40 performs scraping processing by sequentially executing steps S3 to S7. Figure 24 The trajectory TR of the scraper 16 is shown as a solid line when the action flow involved in this embodiment is performed on the workpiece W2. Figure 24As shown, in this embodiment, the scraper 16 moves along the trajectory TR”, abuts against the surface Q1 of the workpiece W1 at position P1’, moves to the right along the surface Q1, and then leaves the surface Q1 at position P2”. Figure 25 The diagram shows the characteristics of the pressing force F changing over time at this point. Furthermore, in... Figure 25 In the diagram, for comparison purposes, the characteristic of the pressure F changing over time during scraping of workpiece W1 is represented by a dashed line (compared to...). Figure 13 correspond).

[0151] like Figure 25 As shown, according to this embodiment, the pressure F delays the scraper 16 from the workpiece W1 compared to when scraping is performed. Figure 24 The time Δt required for position P1 to move to position P1' in the middle starts to increase, but reaches a peak F. P Therefore, the scraper 16 can press the surface Q2 of the workpiece W2 with sufficient pressing force F, thus enabling the depth E of the recess R to reach the desired value.

[0152] Furthermore, in the above embodiment, the case where the operator measures the thickness H of the workpiece W has been described. However, it is not limited to this; the processor 40 may also obtain the thickness H when performing the first scraping process on the workpiece W. Specifically, when the processor 40 determines "yes" in step S14, it obtains the z-axis coordinate z2 of the front end 32a (TCP) of the scraper 16 in the robot coordinate system C1 based on feedback from the rotation detector of the servo motor 34.

[0153] On the other hand, the z-axis coordinate z3 of the mounting surface (not shown) on which the workpiece W is placed in the robot coordinate system C1 is known and pre-stored in memory 42. Processor 40 can calculate the thickness H of workpiece W according to the formula H = z2 - z3. Then, processor 40 can also, in the case of performing a second scraping process on workpiece W, refer to... Figure 23 or Figure 25 The method described is to achieve the peak pressure F. P The way to control execution.

[0154] Furthermore, in the above-described embodiment, the processor 40 can also automatically determine the target value F for force control based on the target depth E of the recess R. T The following explains this function. Here, the depth E of the recess R formed by scraping is compared with the target value F of the force control performed during scraping. T There is a high correlation between them. Specifically, the target value F T The higher the setting, the higher the peak value of the pressing force F during scraping. PThe higher the value, the deeper the resulting recess R becomes, E.

[0155] As an example, the memory 42 of the control device 18 pre-stores a data table DT3, in which the depth E and the target value F are compared. T (or peak F) P The data is stored in an interconnected manner. For example, the DT3 data table can be used to accumulate depth E and target value F through experimental or simulated methods. T The dataset was used to create it.

[0156] Starting with processor 40 Figure 14 Following the illustrated procedure, the operator inputs the target depth E as the processing condition MC. The processor 40 then accepts the input target depth E and determines it as "yes" in step S1. Next, in step S2, the processor 40 searches the data table DT3 for the target value F corresponding to the input target depth E. T and set the target value F T Set as processing condition MC.

[0157] Then, after starting step S13, processor 40 proceeds by setting the target value F. T The processor 40 executes force control to form a recess R with a target depth E. Thus, in this embodiment, the processor 40 automatically determines a target value F that can achieve the target depth E based on the target depth E input by the operator. T It also enables force control. Based on this structure, the depth E of the recess R formed by scraping can be controlled to a desired value.

[0158] Furthermore, in the above embodiment, the processor 40 can also automatically determine the incident angle θ2 based on the target depth E of the recess R. This function will be explained below. Here, there is a high correlation between the depth E of the recess R formed by scraping and the incident angle θ2. For example, the smaller the incident angle θ2 is set, the shallower the depth E of the formed recess R will be.

[0159] As an example, the memory 42 of the control device 18 pre-stores a data table DT4 in which the depth E and the incident angle θ2 are stored in relation to each other. This data table DT4 is created, for example, by experimental methods or by simulating a dataset of accumulated depth E and incident angle θ2.

[0160] Starting with processor 40 Figure 14 Following the process shown, for example, the operator inputs the speed command FC in equation (2) above as the processing condition MC. V_0 and speed command PC V_2(or one of distance x1 and distance z1), and the target depth E. Therefore, the processor 40 accepts the input of the processing condition MC and determines it as "yes" in step S1.

[0161] Next, in step S2, the processor 40 searches for the incident angle θ2 corresponding to the input target depth E from the data table DT4, and sets this incident angle θ2 as the processing condition MC. Additionally, the processor 40 automatically sets the speed command FC using the above equation (1). V_0 and speed command PC V_2 (Or the other one of distances x1 and z1).

[0162] In this embodiment, the processor 40 automatically determines the incident angle θ2 that achieves the target depth E based on the target depth E input by the operator, and automatically sets the incident angle θ2 as the processing condition MC. According to this structure, the depth E of the recess R formed by scraping can be controlled to a desired value.

[0163] Furthermore, in data table DT4, the aforementioned angle θ1 can be stored in association with the target depth E instead of the incident angle θ2. This angle θ1 also has a high correlation with the depth E of the recess R. In this case, in step S2, the processor 40 searches for the angle θ1 corresponding to the input target depth E from data table DT4 and sets this angle θ1 as the processing condition MC.

[0164] Furthermore, in the above-described embodiment, the processor 40 controls the pressure F to a predetermined value during scraping by performing force control together with position control. Figure 13 , Figure 20 , Figure 23 , Figure 25 The situation described is as follows. However, it is not limited to this; the processor 40 can also control the pressing pressure F to a predetermined value and perform scraping by performing only position control. See reference... Figure 26 Let me explain this function.

[0165] exist Figure 26 In the method shown, a teaching point TP is set along the surface Q1 of the workpiece W1. 11 TP 12 TP 13 TP 14 TP 15 TP 16 and TP 17 Here, the teaching point TP is shown. 12 and teaching point TP 16 The teaching point TP is positioned in the robot coordinate system C1 at the same location as surface Q1 along the z-axis.13 TP 14 and TP 15 The position is located below surface Q1 in the robot coordinate system C1. Additionally, at these teaching points TP... n Among (n = 11 to 17), the teaching point TP 14 It is positioned at the bottom of the robot coordinate system C1.

[0166] In this configuration, the processor 40 performs position control, causing the scraper 16 to move to the teach point TP. 11 →TP 12 →TP 13 →TP 14 →TP 15 →TP 16 →TP 17 The scraper 16 moves sequentially from the teach point TP via the robot 12. 11 To the teaching point TP 12 move.

[0167] Thus, the scraper 16 moves in the direction (to the right) along the surface Q1 of the workpiece W, and simultaneously moves in the direction (downward) toward the surface Q1, thereby following a trajectory inclined at the incident angle θ2 at the teaching point TP. 12 The point abuts against the surface Q1 of the workpiece W. In this embodiment, the incident angle θ2 is determined by the distance from the teaching point TP. 11 To the teaching point TP 12 The movement path is specified by MP.

[0168] Then, the processor 40 orients the front end 28b of the robot 12 toward the teaching point TP. 13 and teaching point TP 14 The corresponding position is moved further to the lower right, and then the front end 28b of the hand is oriented towards the teaching point TP. 15 and teaching point TP 16 The corresponding position moves to the upper right. During this period, the processor 40 causes the front end 32a of the scraper 16 to move to the right while pressing the surface Q1 of the workpiece W with a pressing force F.

[0169] Then, the processor 40 causes the scraper 16 to move from the teach point TP. 16 Towards the teaching point TP 17 The scraper 16 moves away from surface Q1 along a trajectory that is inclined at an acute angle θ3 relative to surface Q1. Thus, a surface Q1 is formed with a shape extending from the teaching point TP. 12 To TP 16 The length of the concave portion R.

[0170] Here, it is possible to appropriately select the teaching point (TP). n The position is used to control the pressing pressure F during the scraping process. Figure 13 The characteristics shown vary over time. As an example, memory 42 pre-stores data table DT5, in which the teach point TP is... n The position data (coordinates in robot coordinate system C1) are stored in relation to the magnitude of the pressing force F (or its characteristics over time).

[0171] Using this data table DT5, a teach point TP can be set to control the pressing force F during scraping to the desired value. n Location data. This is achieved by setting teaching points TP as shown in the example. n By performing position control, the processor 40 can control the pressing pressure F during scraping to a size (a characteristic that changes over time) pre-stored in the data table DT5.

[0172] Furthermore, in the above embodiment, the case where a single scraping process is performed on the surface Q of the workpiece W has been described. However, the processor 40 may also repeatedly perform multiple scraping processes to form a plurality of recesses R arranged on the surface Q of the workpiece W. In this case, each of the plurality of recesses R formed is configured separately. Figure 6 , Figure 17 or Figure 26 The set of teaching points TP shown n .

[0173] For example, a setting is made for each of the multiple recesses R. Figure 6 The set of teaching points TP shown n In the case of (n = 1 to 4), Figure 14 In the process shown, the processor 40 sets a first set of teaching points TP for forming the first recess R. n Perform the first step S5, then, for the second set of teaching points TP set to form the second recess R. n The second step S5 is executed. Thus, the processor 40 uses the m-th set of teaching points TP set for forming the m-th recess R. n The scraping process is repeated by performing step S5 (m = 1, 2, 3, ...) for the mth time, thereby forming multiple recesses R.

[0174] Furthermore, the memory 42 can also pre-store the data table DT6 containing the distance x1 or distance z1 and the depth E of the recess R. Moreover, the processor 40 can also, in step S2, search the data table DT6 for the distance x1 or distance z1 corresponding to the input target depth E, and set this distance x1 or distance z1 as the processing condition MC. The distance x1 or distance z1 is also related to the depth E of the formed recess R.

[0175] In the above embodiment, the case where the teaching point TP2 is set such that the front end 32a of the scraper 16 is separated upward relative to the surface Q1 has been described. However, it is not limited to this, the teaching point TP2 may also be configured at the same position (or below) the surface Q1 in the robot coordinate system C1. In this case, the aforementioned incident angle θ2 is defined by the movement path MP from the teaching point TP1 to the teaching point TP2.

[0176] Force sensor 14 can be inserted between the work chamber and the robot base 20, or it can be disposed at any part of the robot 12. Furthermore, force sensor 14 is not limited to being disposed on the robot 12 side; it can also be disposed on the workpiece W side. For example, by inserting force sensor 14 between workpiece W and the mounting surface on which workpiece W is placed, the pressing force F can be detected. Furthermore, force sensor 14 is not limited to a six-axis force sensor; it can be a single-axis or three-axis force sensor, or any sensor capable of detecting the pressing force F.

[0177] Furthermore, in the above embodiment, the case where the origin of the tool coordinate system C2 is located at the front end 32a of the scraper 16 has been described. However, it is not limited to this; for example, the origin of the tool coordinate system C2 can also be located at the center of the front end 28b (wrist flange), and can be located at any position as long as the position of the origin of the tool coordinate system C2 relative to the front end 28b is known.

[0178] Furthermore, the origin of the sensor coordinate system C3 is not limited to being located at the center of the force sensor 14, but can be located at any position known relative to the force sensor 14, and its axes can be defined in any direction. Similarly, the origin of the robot coordinate system C1 is not limited to being located at the center of the robot base 20, but can be located at any position known relative to the robot 12, and its axes can be defined in any direction. The present disclosure has been described above through embodiments, but these embodiments are not intended to limit the invention as defined in the claims.

[0179] Explanation of reference numerals in the attached figures

[0180] 10: Robot system; 12: Robot; 14: Force sensor; 16: Scraper; 18: Control device; 40: Processor.

Claims

1. A robot system for performing scraping processing to flatten the surface of a workpiece, said robot system comprising: A robot that moves a scraper used to scrape the surface; and Control device, which controls the robot in, The control device, via the robot, moves the scraper in a direction along the surface and simultaneously towards the surface, thereby causing the scraper to abut against the surface along a trajectory inclined at an acute angle relative to the surface. During the contact of the scraper with the surface, the control device, while controlling the position of the robot in a predetermined manner with the peak value of the time-varying characteristic of the pressing force by the robot causing the scraper to press against the surface being the same as the value of the scraper, moves the scraper in a direction along the surface via the robot, thereby performing the scraping process.

2. The robot system according to claim 1, wherein, It also includes a force sensor that detects the pressing pressure. During the period when the scraper abuts against the surface, the control device controls the position of the robot by performing force control based on the detection data of the force sensor to control the peak value of the time-varying characteristic of the pressing force to a target value corresponding to the predetermined magnitude.

3. The robot system according to claim 2, wherein, The control device generates position control commands to move the scraper sequentially along the surface toward a plurality of predetermined teach points. When the control device moves the scraper to a teach point TP1 separated from the surface, it begins force control and generates force control commands to move the scraper in the direction toward the surface. The control device causes the scraper to come into contact with the surface along the inclined trajectory by moving the scraper from the teach point TP1 to the teach point TP2 according to the position control command and moving the scraper in the direction toward the surface according to the force control command.

4. The robot system according to claim 3, wherein, The position control command has a first speed command for specifying the speed at which the scraper moves from the teach point TP1 to the teach point TP2. The force control command has a second speed command for specifying the speed at which the scraper moves toward the surface. The control device generates the first speed command and the second speed command in a manner that keeps the acute angle within a predetermined range.

5. The robot system according to claim 2, wherein, The control device moves the scraper away from the surface to end the scraping process at the point when or before the peak value of the time-varying characteristic of the pressing force reaches the target value during the execution of the force control.

6. The robot system according to claim 3, wherein, The control device moves the scraper away from the surface to end the scraping process at the point when or before the peak value of the time-varying characteristic of the pressing force reaches the target value during the execution of the force control.

7. The robot system according to claim 4, wherein, The control device moves the scraper away from the surface to end the scraping process at the point when or before the peak value of the time-varying characteristic of the pressing force reaches the target value during the execution of the force control.

8. The robot system according to claim 2, wherein, After the peak value of the time-varying characteristic of the pressing force, controlled by the force, reaches the target value, the control device continues to perform the scraping process in a manner that maintains the peak value of the time-varying characteristic of the pressing force at the target value.

9. The robot system according to claim 3, wherein, After the peak value of the time-varying characteristic of the pressing force, controlled by the force, reaches the target value, the control device continues to perform the scraping process in a manner that maintains the peak value of the time-varying characteristic of the pressing force at the target value.

10. The robot system according to claim 4, wherein, After the peak value of the time-varying characteristic of the pressing force, controlled by the force, reaches the target value, the control device continues to perform the scraping process in a manner that maintains the peak value of the time-varying characteristic of the pressing force at the target value.

11. The robot system according to any one of claims 1 to 10, wherein, When performing the scraping process, the control device uses the robot to guide the scraper away from the surface along a trajectory that forms an acute angle with respect to the surface, thereby ending the scraping process.

12. The robot system according to any one of claims 1 to 10, wherein, The scraper has: A flexible handle that connects to the forehand end of the robot; and A cutting edge, fixed to the front end of the shank, is used to scrape the surface, wherein the magnitude of the peak value of the time-varying characteristic of the pressing force is determined by the manner in which the shank flexes when the cutting edge is pressed against the surface during the scraping process.

13. The robot system according to claim 11, wherein, The scraper has: A flexible handle that connects to the forehand end of the robot; and A cutting edge, fixed to the front end of the shank, is used to scrape the surface, wherein the magnitude of the peak value of the time-varying characteristic of the pressing force is determined by the manner in which the shank flexes when the cutting edge is pressed against the surface during the scraping process.

14. A method of scraping a surface to make it flat by using a robot that moves a scraper to scrape the surface of a workpiece, wherein... The robot moves the scraper in a direction along the surface and towards the surface simultaneously, thereby causing the scraper to come into contact with the surface along a trajectory inclined at an acute angle relative to the surface. During the contact of the scraper with the surface, the robot's position is controlled in such a way that the peak value of the time-varying characteristic of the pressing force by which the robot presses the scraper against the surface is predetermined, while the robot moves the scraper in a direction along the surface, thereby performing the scraping process.

15. A computer program product comprising a computer program that causes a processor to perform the method according to claim 14.

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