Automatic grinding system and automatic grinding device

Abstract

The present application provides an automatic polishing system and an automatic polishing device, which can adjust the degree of polishing according to the surface state of the body of a moving body. The automatic polishing system (10) comprises: a multi-joint robot (13); a polisher (11) including a spindle (1111) rotating around an axis and a polishing tool (112) fixed to the front end of the spindle (1111); a sensor (12) arranged between the multi-joint robot (13) and the polisher (11), detecting the normal force (z-axis component F z ) acting on the polisher (11) from the polished surface (P) and the torque (z-axis component M z ) acting on the spindle (1111) around the axis; and a control unit (15) controlling the multi-joint robot (13) according to the normal force (z-axis component F z ) and the torque (z-axis component M z ).

Description

Technical Field

[0001] This invention relates to an automatic grinding system and an automatic grinding device. Background Technology

[0002] The technology of applying a protective layer to the coating surface that makes up a car body to maintain the car's appearance as aesthetically pleasingly as possible with minimal effort has become widespread. This protective layer is obtained by applying a liquid glass-based or polymeric material to the coating surface and then allowing it to dry.

[0003] In the application of such a protective layer, the quality of the final product depends on the smoothness of the coating surface. Therefore, the coating surface is usually polished before application to improve its smoothness. Furthermore, to further improve the final quality after coating, the surface of the applied protective layer is also typically polished.

[0004] Typically, skilled craftsmen rely on their experience to grind the surfaces of the coating and protective layer. However, given the shortage of skilled craftsmen and requests to reduce the cost of coating, there is a desire to automate these grinding processes. For example, Patent Document 1 describes a technique that automatically grinds the coating surface of a car body using a grinding machine (a polishing grinding machine in Patent Document 1), while keeping the normal force (a pressing load in Patent Document 1) generated when the grinding machine is pressed against the coating constant.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 1997-262752 Summary of the Invention

[0008] The problem the invention aims to solve

[0009] However, while the technology in Patent Document 1 allows for grinding while maintaining a fixed normal force, it cannot vary the degree of grinding in accordance with the surface condition (e.g., smoothness) of the coating or protective layer. Therefore, it is argued that the technology in Patent Document 1 does not envision varying the degree of grinding in accordance with the surface condition of the coating or protective layer; instead, it grinds the entire surface area of ​​the coating or protective layer at a fixed degree. In other words, it is argued that the technology in Patent Document 1 sets the scanning speed of the grinding machine used to polish the surface of the coating or protective layer to a fixed speed.

[0010] As a result, insufficient polishing may occur in certain areas of the coating or protective layer surface that are in worse condition than other areas. Furthermore, if the scanning speed is set low to accommodate areas in worse condition than other areas, excessive polishing may occur in other areas, unnecessarily extending the time required to polish one vehicle.

[0011] One aspect of the present invention is made in view of the above-mentioned problems, and the object is to provide a technique that can adjust the degree of polishing applied to the surface in accordance with the surface condition of the moving body.

[0012] Solution for solving the problem

[0013] To solve the above problems, an automatic grinding system according to one aspect of the present invention includes an automatic grinding device and a control unit. The automatic grinding device includes the following (1) to (3).

[0014] (1) Multi-joint robot.

[0015] (2) A grinding machine disposed at the front end of the multi-joint robot. The grinding machine includes a main shaft that rotates about an axis and a grinding tool fixed to the front end of the main shaft.

[0016] (3) A sensor disposed between the front end and the grinding machine. The sensor outputs normal force information (information on the normal force acting on the grinding machine from the surface being ground) and torque information (information on the torque acting around the axis of the spindle).

[0017] In addition, the control unit acquires the normal force information and the torque information, and controls the multi-joint robot based on the normal force and the torque.

[0018] To address the aforementioned problems, an automatic grinding apparatus according to one aspect of the present invention comprises: (1) a multi-joint robot; (2) a grinding machine disposed at the front end of the multi-joint robot, including a main shaft rotating about an axis and a grinding tool fixed to the front end of the main shaft; and (3) a sensor disposed between the front end and the grinding machine, outputting normal force information representing the normal force acting on the grinding machine from the surface being ground, and torque information representing the torque of the main shaft.

[0019] The effects of the invention

[0020] According to one aspect of the present invention, an automatic grinding system is provided that can adjust the degree of grinding applied to the surface in accordance with the surface condition of the moving body. Attached Figure Description

[0021] Figure 1 (a) is a schematic diagram of an automatic grinding system according to an embodiment of the present invention. Figure 1 (b) is Figure 1 The diagram (a) shows a perspective view of the automatic grinding system, including the grinder and sensors.

[0022] Figure 2 yes Figure 1 The block diagram of the control unit of the automatic grinding system shown in (a) is shown.

[0023] Figure 3 (a) is Figure 1 The plan view of the surface being ground by the automatic grinding system shown in (a) is a plan view of the surface being ground that shows the trajectory of the spindle and the grinding area. Figure 3 (b) is Figure 1 The modified example of the automatic grinding system shown in (a) is a plan view of the surface to be ground, which shows the trajectory of the spindle and the grinding area.

[0024] Figure 4 This is a flowchart of an automatic grinding method according to one embodiment of the present invention.

[0025] Figure 5 It means as Figure 1 (a) is a block diagram of the structure of the computer that functions as the control unit in the automatic grinding system. Detailed Implementation

[0026] [Structure of the automatic grinding system]

[0027] Reference Figure 1 The structure of an automatic grinding system 10 according to one embodiment of the present invention will be described below. Figure 1 (a) is a schematic diagram of the automatic grinding system 10. Figure 1 (b) is a perspective view of the grinder 11 and sensor 12 of the automatic grinding system 10.

[0028] like Figure 1 As shown in (a), the automatic grinding system 10 includes a grinder 11, a sensor 12, a multi-joint robot 13, a camera 14, and a control unit 15. Furthermore, the grinder 11, the sensor 12, and the multi-joint robot 13 constitute an automatic grinding device as one embodiment of the present invention.

[0029] In this embodiment, the automatic grinding system 10 includes one automatic grinding device. However, the automatic grinding system 10 may also include multiple automatic grinding devices.

[0030] The automatic grinding system 10 uses the surface of the moving body as the grinding surface and automatically grinds the grinding surface under computer control. In this embodiment, a car AM (private vehicle) is used as an example of the moving body to describe the automatic grinding system 10. However, the moving body is not limited to a car AM; it can also be a bus, a truck, or other large vehicle, an aircraft, or a tram. The steel body panel P constituting the surface of the car AM is an example of the grinding surface.

[0031] When the moving body is a car, the automatic grinding system 10 can preferably be used for grinding the coating surface of the car body as a pre-application stage before applying a protective layer to the coating surface constituting the car body. In addition, the automatic grinding system 10 can also preferably be used for grinding in the finishing stage after the protective layer has been applied to the coating surface of the car body.

[0032] In addition, when the moving body is an aircraft or a tram, the body is sometimes repainted to change the design of the body, or a cutting sheet is used to perform fine lapping on the body. The automatic lapping system 10 can preferably be used to lapping the surface of the body as a pre-stage of repainting and fine lapping.

[0033] <Multi-joint robots>

[0034] Figure 1 The multi-joint robot 13 shown in (a) is one type of industrial robot, also known as a vertical multi-joint robot. The multi-joint robot 13 has a base (fixed to the ground), a first joint 131, a first arm 132, a second joint 133, a second arm 134, a third joint 135, and a third arm 136 disposed on the base.

[0035] The base is fixed relative to the ground with an axis perpendicular to the ground as its axis of rotation, and is able to rotate freely about this axis. Figure 1 In (a), the base is obscured by the vehicle AM ​​and is therefore not shown. A first joint 131 is provided at the base.

[0036] One end of the first arm 132 is connected to the first joint 131. The first joint 131 is movable, thereby allowing the angle between the first arm 132 and the ground to change.

[0037] At the other end of the first arm 132, one end of the second arm 134 is connected via a second joint 133. The second joint 133 is movable, thereby allowing the angle between the second arm 134 and the first arm 132 to change.

[0038] At the other end of the second arm 134, one end of the third arm 136 is connected via a third joint 135. The third joint 135 is movable, thereby allowing the angle between the third arm 136 and the second arm 134 to change. Furthermore, the third joint 135 is configured to be parallel to an axis parallel to the direction from one end of the third arm 136 toward the other end. Figure 1 (b) shows the x-axis as the axis of rotation to rotate the third arm 136.

[0039] like Figure 1 As shown in (b), the third arm 136 is a cuboid block that forms the front end of the multi-joint robot 13.

[0040] The first joint 131, the second joint 133, and the third joint 135 operate based on the control signal SC2 generated by the control unit 15 (described later). That is, the multi-joint robot 13 is controlled by the control signal SC2.

[0041] <Grinding machine>

[0042] like Figure 1 As shown in (b), the grinding machine 11 includes a main body 111 and a grinding tool 112 (a polishing tool in this embodiment). The main body 111 includes a motor and a spindle 1111 driven by the motor. The spindle 1111 is a cylindrical component that rotates about its central axis. The spindle 1111 is configured to protrude from one end face of the cylindrical main body 111.

[0043] The other end face of the main body 111 is fixed to one of the four side surfaces constituting the third arm 136 via the sensor 12 described later.

[0044] In addition, Figure 1 In (b), the z-axis is determined parallel to the central axis of the main shaft 1111, the x-axis is determined parallel to the side of the cuboid block that extends from one end of the third arm 136 toward the other, and the y-axis is determined in a right-handed orthogonal coordinate system together with the x-axis and z-axis. The cuboid block constitutes the third arm 136. Furthermore, the direction from the third arm 136 toward the grinding tool 112 in the z-axis direction is defined as the positive z-axis direction, and the direction from one end of the third arm 136 toward the other in the x-axis direction is defined as the positive x-axis direction. The positive y-axis direction is determined in a right-handed orthogonal coordinate system together with the positive x-axis direction and the positive z-axis direction.

[0045] The grinding tool 112 is a disc-shaped grinding element made of felt, cotton, or the like. In this embodiment, the grinding tool 112 has a circular outline when viewed from above. The material constituting the grinding tool 112, its roughness, etc., are not limited; they can be appropriately selected based on the material (e.g., a coating) constituting the surface being ground. The grinding tool 112 is fixed to the front end of the spindle 1111 in such a way that its center is substantially aligned with the central axis of the spindle 1111.

[0046] For the grinding machine 11, the grinding tool 112 is rotated by rotating the spindle 1111. While the spindle 1111 is rotating, the grinding surface of the grinding tool 112 is pressed against the body panel P, thereby the grinding machine 11 grinds the body panel P.

[0047] The main body 111 of the grinding machine 11 receives the control signal SC1 generated by the control unit 15 (described later) and controls the motor to rotate the spindle 1111 based on the control signal SC1. That is, the rotational speed of the grinding tool 112 is controlled by the control signal SC1.

[0048] <Sensor>

[0049] The sensor 12 is positioned between the grinder 11 and the side surface of the third arm 136 that forms the front end of the multi-joint robot 13.

[0050] In this embodiment, sensor 12 is a 6-axis force sensor. Therefore, when the grinding tool 112 is pressed against the body panel P while the main shaft 1111 is rotating about the axis, the following is detected: (1) the x-axis component F of the translational force F acting on the grinding machine 11 from the body panel P. x y-axis component F y and z-axis component F z ; and (2) the x-axis component M of the torque M exerted by the body panel P on the grinding machine 11 x y-axis component M y and z-axis component M z Then, sensor 12 will represent the x-axis component F. x First force information, representing the y-axis component F y The second force information and the representation of the z-axis component F z The third force information, and the representation of the x-axis component M x First torque information, representing the y-axis component M y The second torque information and the representation of the z-axis component M z The third torque information is output to the control unit 15, which will be described later. Furthermore, the x-axis component F will be... x y-axis component F y z-axis component F z x-axis component M x y-axis component My and z-axis component M z Collectively referred to as Sensor Information (SS).

[0051] z-axis component F z This is an example of the normal force acting on the grinding machine 11 from the body panel P, synonymous with the pressing load that presses the grinding machine 11 onto the body panel P. Therefore, by controlling the articulated robot 13 to make the z-axis component F... z Converging within a predetermined range, the compressive load can be kept approximately constant. Additionally, the third force information is an example of normal force information.

[0052] z-axis component M z This is an example of the torque acting around the axis of the main shaft 1111, which can be used as an indicator to evaluate the frictional resistance generated between the body panel P and the grinding machine 11. When grinding the body panel P using the grinding machine 11, as the body panel P is ground, the z-axis component M... z The z-axis component M is reduced. Therefore, the z-axis component M is monitored during the grinding process. z and in the z-axis component M z Grinding is stopped when the condition falls below a predetermined threshold, thereby allowing the grinding level to be adjusted according to the state of the body panel P. Additionally, the third torque information is an example of torque information representing the torque acting around the axis of the main shaft 1111.

[0053] While pressing the grinding machine 11 against the body panel P and scanning the surface of the body panel P with the grinding machine 11, if there is a convex obstacle (such as a door handle) on the surface of the body panel P, the x-axis component F x and y-axis component F y Increase them respectively. Control the multi-joint robot 13 to make the x-axis component F x and y-axis component F y Each converges to a predetermined range, thereby enabling the grinder 11 to scan while avoiding convex obstacles.

[0054] While pressing the grinding machine 11 against the body panel P and scanning the surface of the body panel P with the grinding machine 11, the x-axis component M changes as the inclination of the surface of the body panel P changes. x and y-axis component M y Increase them respectively. Control the multi-joint robot 13 to make the x-axis component M... x and y-axis component M y Each converges to a predetermined range, thereby enabling the grinding machine 11 to scan while simultaneously mimicking the body panel P. Furthermore, the multi-joint robot 13 is controlled to make the x-axis component M... x and y-axis component My They converge to a predetermined range, thereby enabling the central axis of the principal axis 1111 to be aligned. Figure 1 The z-axis shown in (b) is roughly aligned with the normal direction of the body panel P, while the grinding machine 11 performs a scan.

[0055] Furthermore, in one embodiment of the present invention, the sensor 12 outputs at least a z-axis component F. z The third force information and the representation of the z-axis component M z A two-axis force sensor can be used to obtain the third torque information.

[0056] <Camera>

[0057] Camera 14 is a digital camera that outputs information representing the captured image. In this embodiment, camera 14 captures an image of a car AM that has entered the grinding space where the automatic grinding system 10 performs automatic grinding, and outputs image information SI representing the image, which is then supplied to the control unit 15, described later.

[0058] <Control Department>

[0059] The control unit 15 is a structure used to control the operation of the automatic grinding system 10. The control unit 15 acquires sensor information SS generated by the grinding machine 11 and determines the z-axis component F represented by the third force information contained in the sensor information SS. z The z-axis component M represented by the third torque information z This is used to control the multi-joint robot 13. Below, refer to... Figure 2 and Figure 3 Let me explain the functional blocks that make up the control unit 15. Figure 2 This is a block diagram of the control unit 15. Figure 3 (a) is a plan view of the body panel P being ground by the automatic grinding system 10, showing the trajectory of the main shaft 1111 and the ground surfaces of each grinding area RPi (i is a natural number of 1≤i≤n, and n is any positive integer). Figure 3 (b) is a top view of a body panel P being ground in a modified example of the automatic grinding system 10, and a plan view showing the trajectory of the main shaft 1111 and the grinding surfaces of the grinding areas RP1 to RP7.

[0060] like Figure 2 As shown, it includes an image recognition unit 151, a threshold setting unit 152, a grinding machine control unit 153, a robot control unit 154, and a threshold determination unit 155.

[0061] (Image Recognition Department)

[0062] The image recognition unit 151 acquires image information SI from the camera 14. The image recognition unit 151 identifies the manufacturer, vehicle type name, and body color of the vehicle AM ​​contained in the image represented by the image information SI, and generates vehicle information representing the manufacturer, vehicle type name, and body color of the identified vehicle AM. The image recognition unit 151 outputs the vehicle information to the threshold setting unit 152.

[0063] (Threshold setting section)

[0064] The threshold setting unit 152 acquires vehicle information from the image recognition unit 151. Based on the manufacturer, vehicle type, and body color of the vehicle AM ​​represented by the vehicle information, the threshold setting unit 152 sets the z-axis component M. z The threshold is set by the threshold setting unit 152. In this embodiment, the threshold setting unit 152 refers to a lookup table (LUT) and sets the threshold for vehicle AM ​​based on the LUT. The lookup table (LUT) has a threshold inherent to each type of vehicle determined according to the manufacturer, vehicle type name, and body color. The threshold setting unit 152 generates threshold information representing the threshold of vehicle AM ​​and outputs it to the threshold determination unit 155.

[0065] Furthermore, the LUT can also be configured to have a threshold inherent to a single type of vehicle, determined based on at least one of the manufacturer, vehicle type name, and body color. For example, when the LUT is configured to have a threshold inherent to each body color, the threshold setting unit 152 sets the threshold based on the body color of the vehicle AM. Alternatively, if it is not necessary to set a threshold for each vehicle, the threshold can be preset, and the threshold setting unit 152 can be omitted.

[0066] Furthermore, the threshold can also be set using a learned model constructed through machine learning. In this case, for example, a learned model can be output with the manufacturer, vehicle type, and body color of the vehicle AM ​​as input, to determine the appropriate threshold for the vehicle AM. Alternatively, the learning model can be supplemented or replaced by inputting the paint finish of the vehicle AM ​​(e.g., surface roughness, gloss index, paint thickness, etc.) as input. Additionally, a learned model can be output with the appropriate threshold for the vehicle AM ​​using an image containing the vehicle AM ​​as the subject (the image represented by image information SI) as input. In this case, the optimal threshold can be set after considering the manufacturer, vehicle type, body color, and paint finish of the vehicle AM. In this case, the recognition of manufacturer, vehicle type, and body color in the image recognition unit 151 can be omitted.

[0067] In addition, the z-axis component M zIt is related to the frictional resistance generated between the polishing surface of the polishing tool 112 and the polishing area RPi of the vehicle body panel P. Therefore, the following situation may occur: although the z-axis component F z is fixed when polishing the polishing area RPi, the z-axis component M z changes in accordance with the wear degree of the polishing surface of the polishing tool 112. In the automatic polishing system 10, the wear degree of the polishing surface of the polishing tool 112 can be evaluated using a reference surface before starting the polishing of the vehicle body panel P. The reference surface is a surface whose surface roughness (an indicator indicating smoothness) and gloss index (such as gloss, haze, image clarity, BRDF (Bidirectional Reflectance Distribution Function), etc.) are finished to a predetermined state, and is a surface imitating the surface of a vehicle body panel of an automobile. The wear degree of the polishing surface of the polishing tool 112 can be evaluated by monitoring the z-axis component M z in a state where the main shaft 1111 is rotated under the same conditions as those for actually polishing the polishing area RPi and the multi-joint robot 13 is controlled so that the z-axis component F z converges within a predetermined range. It may also be configured such that when the wear degree of the polishing surface is evaluated, the threshold setting unit 152 corrects the threshold of the vehicle AM set based on the LUT according to the evaluation result. According to this structure, even when the wear degrees of the polishing surface of the polishing tool 112 are different, the deviation that may occur in the finished quality (Japanese: finish) of the vehicle body panel P after being polished by the automatic polishing system 10 can be reduced.

[0068] (Polisher Control Unit)

[0069] The polisher control unit 153 generates a control signal SC1 for controlling the polisher 11 and outputs it to the polisher 11. The control signal SC1 includes a control signal for turning on and off the power supply of the motor of the polisher 11, and a control signal for controlling the rotation speed of the motor (that is, the rotation speed of the main shaft 1111).

[0070] (Robot Control Unit)

[0071] The robot control unit 154 generates a control signal SC2 for controlling the multi-joint robot 13 and outputs it to the multi-joint robot 13. The multi-joint robot 13 that has received the control signal SC2 activates the first joint 131, the second joint 133 and the third joint 135 in accordance with the control signal SC2. As a result, the multi-joint robot 13 can arbitrarily control the position of the main shaft 1111 of the polisher 11 on the vehicle body panel P and the z-axis component F z(The pressing load of the grinding machine 11 on the body panel P). Furthermore, the position of the main shaft 1111 of the grinding machine 11 on the body panel P refers to the position obtained by projecting the central axis of the main shaft 1111 onto the surface of the body panel P. Additionally, below, the position of the main shaft 1111 on the body panel P will simply be referred to as the position of the main shaft 1111.

[0072] During the grinding process of the grinding machine 11 on the grinding area RPi (where i is a natural number 1 ≤ i ≤ n, and n is any positive integer), the robot control unit 154 obtains the z-axis component F from the grinding machine 11. z The grinding area RPi is a predetermined area in the body panel P. Then, the robot control unit 154 controls the articulated robot 13 to make the z-axis component F... z It converges to a predetermined range. As a result, the pressing load remains approximately constant during the grinding process.

[0073] exist Figure 3 In the example shown in (a), the robot control unit 154 first controls the articulated robot 13 so that the position of the spindle 1111 is aligned with point P1, which serves as the starting point for grinding. Point P1 is the center of the grinding area RP1. Furthermore, the radius of the grinding area RP1 is approximately the same as the radius of the grinding tool 112. At this point, each grinding area RPi is identical to the grinding area RP1, and each point Pi is identical to point P1.

[0074] The robot control unit 154 fixes the position of the spindle 1111 at point P1 until it obtains grinding completion information indicating that grinding is complete from the threshold determination unit 155 (described later).

[0075] When the robot control unit 154 receives grinding completion information from the threshold determination unit 155, it moves the position of the spindle 1111 from point P1 to point P2. As a result, the grinder 11 grinds the grinding area RP2.

[0076] As described above, during the grinding of the body panel P by the grinding machine 11, as long as i is greater than 1 and less than n, the robot control unit 154 repeatedly moves the spindle 1111 to a predetermined position (in Figure 3 (a) describes the stroke of points P1 to P7 and the process of fixing the spindle 1111 at each predetermined position (points P1 to P7).

[0077] Furthermore, the robot control unit 154 can also be configured to control the multi-joint robot 13 to trace a periodic trajectory of the position of the spindle 1111 in each grinding area RPi during the grinding of the body panel P by the grinding machine 11 (see reference). Figure 3 (b)). In Figure 3In the example shown in (b), the robot control unit 154 controls the articulated robot 13 so that the central axis of the main axis 1111 traces the trajectory of “∞”.

[0078] (Threshold Determination Section)

[0079] During the grinding process of the grinding machine 11 on a predetermined area, namely the grinding area RPi, of the body panel P, the threshold determination unit 155 obtains the z-axis component M from the grinding machine 11. z Additionally, the threshold determination unit 155 obtains threshold information representing the threshold of the vehicle AM ​​from the threshold setting unit 152. Then, the threshold determination unit 155 determines the z-axis component M... z Compared with the threshold represented by the threshold information, in the z-axis component M z If the value is below the threshold, the threshold determination unit 155 determines that the grinding of the grinding area RPi is complete. At this time, the threshold determination unit 155 outputs grinding completion information indicating that the grinding of the grinding area RPi is complete to the robot control unit 154.

[0080] As long as i is greater than or equal to 1 and less than or equal to n, the threshold determination unit 155 repeats this process.

[0081] Furthermore, when the robot control unit 154 is configured to trace a periodic trajectory of the position of the spindle 1111 in each grinding zone RPi (see reference) Figure 3 (b)), the threshold determination unit 155 in the z-axis component M z If the maximum value in one cycle is below the threshold, the grinding of the grinding area RPi is considered complete.

[0082] <Automatic Grinding Method>

[0083] In the automatic grinding system 10, refer to Figure 4 To explain the automatic grinding method M15 implemented by the control unit 15. Figure 4 This is a flowchart of the automatic grinding method M15.

[0084] like Figure 4 As shown, the automatic grinding method M15 includes an image recognition step S151, a threshold setting step S152, a step of starting the grinding machine S153a, a robot control step S154, a threshold determination step S155, and a step of stopping the grinding machine S153b.

[0085] Image recognition process S151 is Figure 2The image recognition unit 151 shown performs the following process. In the image recognition process S151, the manufacturer, vehicle type name, and body color of the car AM contained in the image represented by the image information SI are recognized, and car information representing the manufacturer, vehicle type name, and body color of the recognized car AM is generated.

[0086] Threshold setting procedure S152 is Figure 2 The threshold setting unit 152 shown performs the following steps. In the threshold setting step S152, the z-axis component M is set based on the manufacturer, vehicle type name, and body color of the vehicle AM ​​as indicated in the vehicle information. z The threshold.

[0087] The steps S153a for starting the grinding machine and S153b for stopping the grinding machine are... Figure 2 The process performed by the grinding machine control unit 153 shown.

[0088] Robot control process S154 is Figure 2 The robot control unit 154 shown performs the following process. In robot control process S154, during the grinding machine 11 grinding a predetermined area, i.e., the grinding area RPi, in the body panel P, the z-axis component F is obtained from the grinding machine 11. z Then, the robot control unit 154 controls the articulated robot 13 to make the z-axis component F z It converges to a predetermined range.

[0089] In addition, in the robot control process S154, the position of the spindle 1111 is moved to point P1, which serves as the starting point for grinding. After that, the robot control unit 154 fixes the position of the spindle 1111 at point P1 until the grinding of the grinding area RP1 is completed.

[0090] Threshold determination process S155 is Figure 2 The threshold determination unit 155 shown performs the following process. In the threshold determination process S155, during the grinding of the grinding area RPi by the grinding machine 11, the z-axis component M is... z Compared with the threshold represented by the threshold information, in the z-axis component M z If the value is below this threshold, the grinding of the grinding area RPi is considered complete.

[0091] In the automatic grinding method M15, the robot control process S154 and the threshold determination process S155 are repeated alternately as long as i is 1 or more and n is less than n. In addition, if i exceeds n, the process S153b that stops the grinding machine is implemented, and the automatic grinding method M15 ends.

[0092] (An example of software implementation in the control unit)

[0093] Some or all of the functions of the control unit 15 can be implemented by hardware such as integrated circuits (IC chips) or by software. In the latter case, the functions of the control unit 15 are implemented, for example, by a computer that executes commands as a program P, which is software.

[0094] Figure 5 An example of such a computer is shown (hereinafter referred to as Computer C). For example... Figure 5 As shown, computer C has at least one processor C1 and at least one memory C2. Memory C2 stores a program P for causing computer C to operate as a control unit 15. In computer C, processor C1 implements the various functions of control unit 15 by reading and executing program P from memory C2.

[0095] As the processor C1, it can be, for example, a CPU (Central Processing Unit), GPU (Graphics Processing Unit), DSP (Digital Signal Processor), MPU (Micro Processing Unit), FPU (Floating Point Number Processor), PU (Physics Processing Unit), microcontroller, or a combination thereof. As the memory C2, it can be, for example, flash memory, HDD (Hard Disk Drive), SSD (Solid State Drive), or a combination thereof.

[0096] In addition, computer C may also include RAM (Random Access Memory), which is used for program P to expand or temporarily store various data during execution. Furthermore, computer C may also have a communication interface for sending and receiving data with other devices. Additionally, computer C may also have input / output interfaces for connecting input devices such as keyboards and mice and / or output devices such as monitors and printers.

[0097] Furthermore, program P can be recorded on a non-transitory tangible recording medium M that can be read by computer C. Such a recording medium M can be, for example, tape, disk, card, semiconductor memory, or programmable logic circuit. Computer C can acquire program P via such a recording medium M. Alternatively, program P can be transmitted via a transmission medium. Such a transmission medium can be, for example, a communication network or broadcast waves. Computer C can also acquire program P via such a transmission medium.

[0098] (Summarize)

[0099] According to one aspect of the present invention, an automatic grinding system can adjust the degree of grinding applied to the surface being ground in accordance with the state of the surface. Furthermore, examples of surfaces to be ground include the surface of a moving body. Additionally, according to other embodiments, the degree of grinding applied to the surface can be reliably adjusted. Furthermore, according to other embodiments, a threshold can be automatically set based on the manufacturer, vehicle type, and color of the vehicle being ground. Furthermore, according to other embodiments, during the grinding of a predetermined area of ​​the surface being ground, the spindle continuously moves in a manner that traces a periodic trajectory, thereby reducing any grinding marks that may remain on the surface. Furthermore, according to other embodiments, a system that automatically grinds the surface while mimicking its shape can be implemented using a simple structure. Furthermore, according to other embodiments, multiple automatic grinding devices can be used to grind the surface in parallel, thereby shortening the grinding time.

[0100] The automatic grinding apparatus according to one aspect of the present invention achieves the same effect as the automatic grinding system according to another aspect.

[0101] [Additional Items]

[0102] This invention is not limited to the embodiments described above, and various modifications can be made within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included within the technical scope of this invention.

[0103] Explanation of reference numerals in the attached figures

[0104] 10: Automatic grinding system; 11: Grinding machine; 111: Main body; 1111: Spindle; 112: Grinding tool; 12: Sensor; 13: Multi-joint robot; 131: First joint; 132: First arm; 133: Second joint; 134: Second arm; 135: Third joint; 136: Third arm (front end of the multi-joint robot); 14: Camera; 15: Control unit; 151: Image recognition unit; 152: Threshold setting unit; 153: Grinding machine control unit; 154: Robot control unit; 155: Threshold determination unit.

Claims

1. An automatic grinding system, characterized in that, Equipped with an automatic grinding device and control unit, The automatic grinding device includes: Multi-joint robot; A grinding machine, disposed at the front end of the articulated robot, includes a main shaft rotating about an axis and a grinding tool fixed to the front end of the main shaft; and A sensor, disposed between the front end and the grinding machine, outputs normal force information representing the normal force acting on the grinding machine from the surface being ground, and torque information representing the torque of the spindle. The control unit acquires the normal force information and the torque information, and controls the multi-joint robot based on the normal force and the torque. The control unit includes: A robot control unit controls the articulated robot to converge the normal force to a predetermined range during the grinding process of the grinding machine on a predetermined area, the grinding area being a predetermined region within the surface being ground; and If the torque is below a predetermined threshold, the threshold determination unit determines that the grinding of the grinding area is complete. The surface being ground is the surface of the coating covering the car body. The automatic grinding system also includes a camera that outputs image information containing an image of the vehicle. The control unit further includes a threshold setting unit, which sets the threshold based on a car determined from at least one of the car manufacturer, vehicle type name, and body color contained in the image represented by the image information. The robot control unit controls the articulated robot to make the position of the spindle on the surface being ground trace a periodic trajectory with the start and end points consistent within a predetermined area, i.e., the grinding area, during the grinding process of the grinding machine. If the maximum value of the torque in one cycle is below the threshold, the threshold determination unit determines that the grinding of the grinding area is complete.

2. The automatic grinding system according to claim 1, characterized in that, The sensor is a 6-axis force sensor. The control unit controls the multi-joint robot based on the translational force, including the normal force, acting on the grinding machine from the surface being ground, and the torque, including the torque around the spindle, acting on the grinding machine from the surface being ground, so that the grinding tool imitates the surface being ground.

3. The automatic grinding system according to claim 1, characterized in that, It is equipped with multiple of the aforementioned automatic grinding devices.

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