Polishing method, manufacturing method for metal die-cast product, polishing device, computer program and control device

Abstract

To provide a polishing method that can suitably polish even a member of interest having a complicated surface, and a method for producing a metal die-cast article, a polishing device, a computer program and a controller.SOLUTION: A polishing method has a step for polishing a surface of a workpiece W held by a robot arm 20 so that a brush B, a rotating polisher, moves over it. The robot arm has a flexible drive mechanism. The workpiece W is a metal die-cast molding to be polished.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a polishing method, a manufacturing method for a metal die-cast product, a polishing device, a computer program, and a control device. [Background technology]

[0002] When forming metals by die casting, reaction inhibitors or fluxes containing calcium, sulfur, etc. are added to suppress oxidation reactions during metal melting. In particular, when die casting metals such as magnesium and aluminum, which have a high ionization tendency and are easily oxidized, such reaction inhibitors are added.

[0003] However, the surface of a metal die-cast product formed by such a method may have precipitates or coatings (hereinafter, foreign matter such as precipitates and coatings present on the surface of the molded product will be collectively referred to as "precipitates") due to reactions during molding, added substances, etc. If precipitates remain, part of the surface of the die-cast product will be covered by the precipitates, making it difficult to detect defects such as pinholes by visual inspection. Another problem is that the aesthetic appearance of the metal die-cast product will be impaired.

[0004] For this reason, it is preferable to remove the precipitates after die casting. Conventionally, the precipitates have been removed by polishing the surface of the metal die casting product with a polishing member such as a buff or brush by an operator.

[0005] Patent Document 1 describes a grinding device equipped with a robot arm equipped with a belt sander for grinding excess weld beads of welded structures. This grinding device makes it possible to adjust the grinding depth by adjusting the position of a guide plate.

[0006] Patent Document 2 describes a polishing device for polishing press dies, in which a polishing tool for polishing a workpiece is attached to the tip of a robot arm. This polishing device enables polishing with a constant force by feedback controlling the output of a force sensor.

[0007] Patent Document 3 describes a polishing device for buffing the front grille of an automobile, which issues an offset signal to a robot hand to correct its position when the current value of the motor is below a certain value. This polishing device controls the position of the robot hand so that the current value to the motor is above a certain value, thereby enabling polishing with a force above a certain level. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 10-202493 [Patent Document 2] Japanese Patent Application Publication No. 3-149171 [Patent Document 3] Japanese Patent Application Publication No. 6-8130 Summary of the Invention [Problem to be solved by the invention]

[0009] However, the devices described in each of the patent documents all have a specialized configuration for polishing a specific workpiece, and the surface of the workpiece to be polished is limited to a flat surface. For this reason, it is difficult for any of the devices to suitably polish a complex surface having irregularities. In particular, burrs often occur on the end of molded products, and the shape and size of the burrs are uncertain, making it difficult to deal with cases where the shape of the object to be polished is not constant.

[0010] Therefore, an object of the present invention is to provide a polishing method, a manufacturing method for metal die-cast products, a polishing apparatus, a computer program, and a control device that are capable of effectively polishing even polished members having complex surfaces. [Means for solving the problem]

[0011] The present disclosure provides a polishing method including a step of polishing a surface of a member to be polished by rotating a polishing member held by a robot arm having a flexible drive mechanism.

[0012] The present invention also provides a polishing method including a step of polishing the surface of a member to be polished held by a robot arm having a flexible drive mechanism by following the surface of the rotating polishing member.

[0013] Here, "having flexibility" refers to having elasticity, viscosity, or both elasticity and viscosity. Elasticity refers to the property of being deformed when stress is applied and returning to the original shape when the stress is removed, and is sometimes expressed as the term flexibility, which indicates the ease of elastic deformation. Viscosity refers to the property of generating stress that makes the flow speed of a fluid uniform. The flexible drive mechanism may include at least one of, for example, a magnetic fluid, a mechanical spring, an air spring, a magnetic spring, and a vane motor to impart flexibility.

[0014] The terms "the polishing member" and "the surface of the polished member" refer to moving the polishing member relative to the surface of the polished member while keeping the polishing member in contact with the surface of the polished member. Relative movement is not limited to translational movement, but also includes relative rotational movement.

[0015] The polishing may be performed while maintaining the force acting from the polishing member on the surface of the workpiece within a substantially constant range.

[0016] Here, "approximately a constant range" includes, for example, a range in which the maximum and minimum values ​​of the force within a certain period of time are within ±50% of the average value.

[0017] In one embodiment of the present disclosure, the polished member is made of a magnesium alloy. The polished member may be a metal die-cast product.

[0018] In one aspect of the present disclosure, the abrasive member is constructed from brass.

[0019] In one aspect of the present disclosure, the robot arm may have a plurality of drive shafts, and each of the plurality of drive shafts may include a series elastic actuator as the flexible drive mechanism.

[0020] The series elastic actuator includes, for example, a motor and an elastic body such as a spring. The torque output from the motor is transmitted to a link having rigidity via the elastic body. This makes it possible to easily realize the polishing member or polishing member held by the robot arm coming into contact with the polishing member or polished member to conform to the surface of the polishing member. It is preferable to make the polishing member conform to the surface of the polishing member so that the elastic body included in the series elastic actuator is elastically deformed.

[0021] In one aspect of the present disclosure, the polishing member is composed of a brush having a plurality of linear bodies. When such a polishing member is rotated, the centrifugal force causes the tips of the linear bristles to spread in a direction perpendicular to the axis of rotation. By making the tip of the polishing member rotate in this manner conform to the surface of the polished member held by the robot arm, it is possible to make the tip of the polishing member reach a recess or the like on the surface. The robot arm may change the position of the polishing member or the polished member so that the extension direction of the polishing member when rotated roughly coincides with the normal line of the surface of the polished member facing it. Here, changing the position includes changing the posture. In addition, "the extension direction of the polishing member roughly coincides with the normal line of the surface of the polished member facing it" means that the absolute value of the angle between a straight line approximating the extension direction of the polishing member and the normal line at the position on the surface of the polished member through which the straight line passes is 45 degrees or less.

[0022] In one aspect of the present disclosure, the method may further include, after the polishing step, applying a coating material to the surface of the polished member using the robot arm.

[0023] In one aspect of the present disclosure, the method may further include a step of setting a path along which the polishing member and the member to be polished interfere with each other, and in the polishing step, the robot arm may move the polishing member or the member to be polished based on the path.

[0024] Moreover, one aspect of the present disclosure provides a method for manufacturing a metal die-cast product, the method including the steps of performing metal die-casting and performing the polishing method using the metal die-cast product formed by the step as the polished member.

[0025] In one aspect of the present disclosure, the robot arm may hold a runner portion of the member to be polished and perform the polishing method.

[0026] In one embodiment of the present disclosure, the method may further include removing flash and runner portions of the metal die-cast product formed by the metal die casting.

[0027] One aspect of the present disclosure provides a polishing apparatus having a flexible drive mechanism, a robot arm configured to hold a polishing member, and configured to rotate the polishing member while conforming it to the surface of a member to be polished for polishing.

[0028] One aspect of the present disclosure provides a polishing apparatus having a flexible drive mechanism, a robot arm configured to hold a polished member, and configured to polish the surface of the polished member by aligning it with a rotating polishing member.

[0029] One aspect of the present disclosure provides a control device that controls a robot arm having a flexible driving mechanism and a holding mechanism capable of holding a polishing member, and is configured to be capable of executing a step of using the robot arm to rotate the polishing member while aligning it with the surface of a member to be polished.

[0030] One aspect of the present disclosure provides a control device that controls a robot arm having a flexible driving mechanism and a holding mechanism capable of holding a member to be polished, and is configured to be capable of executing a step of using the robot arm to polish the surface of the member to be polished by aligning it with a rotating polishing member.

[0031] One aspect of the present disclosure provides a computer program for generating control instructions for operating a robot arm to execute a step of polishing a surface of a workpiece by rotating the polishing member using a robot arm including a flexible driving mechanism and a holding mechanism capable of holding the polishing member. The computer program may be non-temporarily stored in a recording medium such as a semiconductor memory.

[0032] One aspect of the present disclosure provides a computer program for generating control instructions for operating a robot arm to execute a step of polishing a surface of a polished member by following a rotating polishing member using a robot arm having a flexible driving mechanism and a holding mechanism capable of holding the polished member. The computer program may be non-temporarily stored in a recording medium such as a semiconductor memory. [Brief description of the drawings]

[0033] [Figure 1] FIG. 1 is a diagram showing a schematic diagram of a manufacturing process for a metal die-cast product. [Diagram 2] FIG. 2 is a schematic diagram showing an example of a robot arm of the polishing apparatus. [Diagram 3] FIG. 3 is an example of a functional block diagram of the polishing apparatus. [Figure 4] FIG. 4 is an example of a flow chart of a manufacturing process for a metal die-cast product. [Diagram 5] FIG. 5 is a schematic diagram showing an example of a mold used in metal die casting. [Figure 6] FIG. 6 is a schematic diagram showing how the tip of the brush is polishing a recess on the surface of a workpiece. [Figure 7] FIG. 7 is a graph for explaining the deceleration operation when the permissible range is exceeded during the tracing operation. [Figure 8] FIG. 8 is a schematic diagram showing a state in which a workpiece having a convex surface is being polished. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following embodiments are merely examples for explaining the present invention, and are not intended to limit the present invention to the embodiments.

[0035] FIG. 1 is a diagram showing a schematic diagram of a manufacturing process of a metal die-cast product including a polishing method according to the present embodiment. FIG. 2(A) is a schematic diagram showing an example of a robot arm 20 of a polishing apparatus 100 according to the present embodiment. FIG. 3 is an example of a functional block diagram of the polishing apparatus 100 according to the present embodiment. FIG. 4 is an example of a flowchart of a manufacturing process of a metal die-cast product. FIG. 5 is a schematic diagram showing an example of a mold used in metal die-casting.

[0036] FIG. 1 shows a state in which a workpiece W (an example of a "part to be polished"; hereinafter, sometimes simply referred to as a "molded product"), which is a metal die-cast product formed by performing metal die casting, is transported on a conveyor C1. The workpiece W transported to the conveyor C1 is picked up by a robot arm 20, and polished by having the surface of the workpiece W imitate a rotating brush B (an example of a "polishing member"). The robot arm 20 then places the polished workpiece W on the downstream conveyor C2. Burrs, runners, etc. remaining on the workpiece W are then removed by a deburring die. A metal die-cast product is manufactured by such a process, which will be described in detail below.

[0037] [Polishing equipment configuration] A polishing apparatus 100 (FIG. 3) according to this embodiment includes a robot arm 20, a control device 10 that controls the robot arm 20, an imaging device 30 that images a workpiece W, and a teaching device 40. The polishing apparatus 100 according to this embodiment is configured to be capable of polishing the surface of the workpiece W by causing a rotating brush B to follow the surface of the workpiece W held by the robot arm 20.

[0038] As shown in Fig. 2(A), the robot arm 20 is, for example, a vertical articulated robot, and includes a base (not shown) fixed to a floor or the like, a plurality of links 20L, joints 20J connecting the links 20L, and a plurality of serial elastic actuators 20D (Fig. 3) for rotationally driving the links 20L at the joints 20J. The robot arm 20 according to this embodiment is a seven-axis vertical articulated robot, and is configured to be able to move the workpiece W held by the link 20L at the tip by a large amount by extending the link 20L without moving the base. However, the robot arm is not limited to this embodiment, and may be, for example, a horizontal articulated robot device or a parallel link robot device.

[0039] The link 20L is made of a rigid member and includes a plurality of links 20L including, for example, a link 20L corresponding to a torso rotatably attached to a base, a link 20L corresponding to an upper arm rotatably attached to the torso, a link 20L corresponding to a forearm rotatably attached to the upper arm, and a link 20L corresponding to a hand rotatably attached to the forearm.

[0040] A holding mechanism for holding a workpiece is provided on the link 20L at the tip of the robot arm 20. The holding mechanism can be configured, for example, from an end effector 20L1 equipped with a pair of movable plates (sometimes called grippers) that are opened and closed by an actuator. Such an end effector 20L1 is attached to the link 20L at the tip, and the workpiece W can be held by clamping it with the movable plates or the like. As other holding mechanisms, a configuration equipped with a plurality of suction pads for holding the workpiece W and an actuator that generates negative pressure on the suction pads based on a control signal transmitted from the control device 10, or, in the case of a workpiece W made of a magnetic material, a configuration equipped with a coil for electromagnetically generating a magnetic field for holding the workpiece W by magnetic force may be adopted.

[0041] The robot arm 20 according to this embodiment includes a plurality of series elastic actuators 20D (an example of a "flexible drive mechanism") for rotationally driving each of the multiple links 20L.

[0042] The series elastic actuator 20D is a known drive mechanism also called an SEA (Serial Elastic Actuator), and an example of an SEA is described in, for example, European Patent No. 2,890,528. The series elastic actuator 20D is composed of a drive unit 20DA and an elastic body 20DE connected to the drive unit 20DA. The drive unit 20DA is composed of, for example, a servo motor. The elastic body 20DE is composed of, for example, a mechanical spring. In the series elastic actuator 20D, the power output from the drive unit 20DA is transmitted via the elastic body 20DE to the output side link 20L (however, in the case of the tip link 20L, the workpiece is included), causing it to rotate.

[0043] Furthermore, the series elastic actuator 20D is equipped with a plurality of sensors including a sensor for acquiring the magnitude of the load, a sensor for acquiring the amount of displacement of the elastic body 20DE, and a sensor for acquiring the amount of displacement of the servo motor.

[0044] The magnitude of the load can be obtained, for example, from a current sensor that obtains the amount of current flowing through a servo motor that constitutes the drive unit 20DA.

[0045] The amount of displacement of the elastic body 20DE can be obtained from optical sensors provided at both ends of the elastic body 20DE to obtain the amount of displacement (rotation angle) at both ends of the elastic body 20DE, a magnetic sensor that detects the magnetic field generated from a magnet or the like attached to the elastic body 20DE, or a strain sensor or the like provided on the elastic body 20DE. It is also possible to obtain the amount of displacement of the elastic body 20DE and the torque generated based on the elastic constant of the elastic body 20DE.

[0046] As in the above, the amount of displacement of the servo motor can be obtained from an optical sensor such as an encoder, a magnetic sensor such as a Hall element, or a strain sensor.

[0047] With the above configuration, an equation of motion is established with parameters including the inertia, mass, and length of the part driven by the series elastic actuator 20D, which corresponds to a flexible driving mechanism, external force, and the elastic modulus of the mechanical spring, which is the elastic body 20DE. Therefore, the control device 10 is configured to perform mechanical compliance control that controls impedance based on the elastic modulus and displacement amount of the mechanical spring.

[0048] The series elastic actuator 20D may include a gear connected to the drive shaft of a servo motor, which is the drive unit 20DA, and transmitting power to an elastic body 20DE, such as a mechanical spring. The series elastic actuator 20D may further include a damper mechanism that absorbs impact based on viscosity and a clutch mechanism for switching the transmission of power. When a viscous body, such as a viscous damper mechanism, is added, or when damping caused by friction between gears, etc. is added, an equation of motion is established in which a viscosity constant is added as a parameter.

[0049] For example, in the case of a series elastic actuator 20D in which a gear is connected to the drive shaft of a servomotor and a load (such as a downstream link) is connected to the output shaft of the gear via an elastic body, the torque generated in the output shaft of the gear is proportional to the current flowing through the servomotor and the gear ratio, and an equation of motion is established in which this torque is equal to the sum of the angular acceleration of the output shaft of the gear multiplied by the inertia, the angular acceleration of the output shaft of the gear multiplied by the viscosity of the gear, and the displacement of the elastic body multiplied by the elastic modulus. By deriving the transfer function of the series elastic actuator 20D based on this equation of motion, mechanical compliance control for controlling impedance becomes possible.

[0050] With the above-described configuration, it becomes possible to rotate the multiple links 20L of the robot arm 20, and therefore it becomes possible to freely change the position and posture of the workpiece W attached to the tip of the link 20L. Note that the information indicating the position in this disclosure may include information indicating the posture if it is considered reasonably necessary.

[0051] The robot arm 20 further includes an input / output unit 20C including a display for transmitting and receiving information to and from the user. The input / output unit 20C is equipped with an imaging device for image recognition of the brush B, which is the member to be polished. Image information of the brush B captured by this imaging device is transmitted to the control device 10. The polishing member information acquisition unit 10F of the control device 10 acquires information indicating the degree of wear and the degree of spread of the brush B by extracting the outline of the brush B based on the image information of the brush B. If the brush B is significantly worn and shortened, the surface of the member to be polished is easily scratched. Also, if the brush B is significantly spread, polishing cannot be performed properly. In such a case, the control device 10 causes the input / output unit 20C to issue a warning indicating that it is time to replace the brush B.

[0052] The robot arm 20 may include a link that is driven by the drive unit 20A that does not have elasticity.

[0053] The polishing apparatus 100 further includes an imaging device 30 for imaging the workpiece W transported on the conveyor C1 and acquiring information about the workpiece W. The image information about the workpiece W captured by the imaging device 30 is transmitted to the control device 10. The polished member information acquisition unit 10G of the control device 10 identifies the portion held by the robot arm 20 by extracting the contour of the workpiece W based on the image information about the workpiece W. The conveyor C1 may be configured to be stationary until the workpiece W is imaged by the imaging device 30 and held by the robot arm 20. When multiple types of workpieces W are transported on the conveyor C1, the polished member information acquisition unit 10G is configured to be able to identify the type of workpiece W based on the image information about the workpiece W.

[0054] The control device 10 controls the robot arm 20. As described above, the control device 10 controls the robot arm 20 based on mechanical compliance control using the series elastic actuator 20D, rather than the conventional position control. Therefore, even if the relative positional relationship between the member to be polished (workpiece) and the polishing member (brush) changes, it is possible to bring the polishing member into contact with the surface of the member to be polished.

[0055] For example, in a brush consisting of many elongated linear bodies, if the linear bodies become shorter due to wear, the positional relationship between the tip of the linear body and the workpiece will change when the brush is rotated. In addition, the shape of burrs and the position of deposits in molded products formed by die casting have individual differences, which also cause the positional relationship between the two to change.

[0056] The robot arm of the conventional polishing device has the structural rigidity and servo rigidity as high as possible in order to improve the accuracy of position and posture control. Therefore, if the positional relationship between the two changes due to wear or burrs on the brush, it is difficult to polish the object appropriately. If the distance between the polished member and the polishing member is too close, the polished member will be damaged, while if the polished member and the polishing member are brought into contact with each other with as little force as possible to suppress the damage, the polished member cannot be polished sufficiently, and it is particularly difficult to polish the object while avoiding burrs. The polishing device according to this embodiment is capable of bringing the polishing member into contact with the surface of the polished member appropriately even if the relative positional relationship between the polished member and the polishing member changes. This will be described in detail below.

[0057] As shown in FIG. 3, the control device 10 includes a start position acquisition unit 10A that acquires the start position and posture at that time of a reference position of the robot arm 20 (for example, the center point of the link 20L or the end effector 20L1 corresponding to the hand position, or the center point on the surface of the workpiece W, etc.; hereinafter referred to as the "reference position"), a target position acquisition unit 10B that acquires a target position and the posture at that time, an allowable range acquisition unit 10C, a path acquisition unit 10D that acquires a path connecting the start position and the target position, a control command acquisition unit 10E that acquires control commands for controlling servo motors corresponding to the drive units 20DA of each series elastic actuator 20D according to the path acquired by the path acquisition unit 10D, a polishing member information acquisition unit 10F that acquires information regarding the polishing member, a polished member information acquisition unit 10G that acquires information regarding the workpiece W, and a memory unit 10H that stores information necessary for each process described in the present disclosure.

[0058] The start position acquisition unit 10A acquires the start position of a series of operations and the posture of the robot arm 20 at that time. For example, the start position acquisition unit 10A acquires the position (including posture) at which holding of the workpiece W starts as the start position. In this case, the start position acquisition unit 10A acquires information indicating the outline of the workpiece W on the conveyor C1 from the polished member information acquisition unit 10G, and acquires the position (including posture) of the robot arm 20 at the time of starting to hold the workpiece W as the start position based on this. Note that the start position input from a teaching device 40 connectable to the control device 10 and the posture of the robot arm 20 at that time may also be acquired as the start position.

[0059] Regarding the portion where the robot arm 20 holds the workpiece W, the manufacturing process for metal die-cast products in this embodiment is specified to execute a step of removing the portion including the runner of the workpiece W after executing the polishing step. This manufacturing process enables the robot arm 20 to execute the polishing step while holding the portion of the workpiece W that will ultimately be removed. Therefore, it becomes possible for the robot arm 20 to polish most of the surface of the product portion of the workpiece W without changing the workpiece W over.

[0060] In particular, the robot arm 20 is configured to hold a portion including a gate runner (hereinafter, may be simply referred to as a "runner portion") of the workpiece W. The portion including the gate runner is provided in a suitable position for spreading molten metal (molten metal) throughout the cavity, and is therefore also suitable as a portion to be held by the robot arm 20.

[0061] The target position acquisition unit 10B acquires, for example, a target position and the orientation at that time input from the teaching device 40. The target position acquisition unit 10B is capable of acquiring a plurality of target positions and the orientations at that time.

[0062] The target position is set to a position and posture where the polishing member can suitably polish the workpiece. Specifically, the target position is set so that the polishing member and the workpiece interfere with each other. In this embodiment, the target position is set so that the surface of the workpiece W, which is the workpiece to be polished, is present within the area through which the brush B, which is the polishing member, rotates and passes.

[0063] By setting the target position in this manner, the series elastic actuator 20D of the robot arm 20 can exert its flexibility, so that it becomes possible to make the brush B conform to the surface of the workpiece W during polishing.

[0064] Furthermore, it is preferable to set the target position so that the tip of the linear body of the rotating brush B reaches recesses, gaps, etc. on the surface of the workpiece to be polished even when the tip of the linear body of the rotating brush B is worn. Therefore, it is preferable to set the target position so that the surface of the workpiece W, which is the workpiece to be polished, is present within the area through which the brush B rotates and passes when it is replaced due to wear or immediately before replacement. By setting the target position in this manner, it is possible to make the tip of the brush B reach recesses, gaps, etc. on the surface of the workpiece to be polished even when the brush B is worn. The position of the tip of the linear body of the brush can be grasped in advance based on the rotation speed of the brush and the material, shape, mass, etc. of the linear body. Therefore, it is preferable to determine the target position based on the rotation speed, material, shape, mass, etc. of the workpiece to be polished.

[0065] In addition, if the extension direction of the linear body of brush B becomes parallel to the surface of the workpiece facing the linear body, it becomes difficult to polish the surface of the workpiece appropriately. For this reason, it is preferable to set the target position (including the posture) so that the extension direction of the linear body, which is the polishing member, when brush B is rotated, roughly coincides with the normal line of the surface of the workpiece W facing it. For example, when the tip of brush B faces vertically, it is preferable to set the target position so that the surface of the opposing workpiece W faces roughly upward. If the extension direction of the linear body is tilted due to rotation, the surface of the workpiece W may be tilted taking this into consideration.

[0066] As described later, even at positions on the path connecting adjacent target positions, by setting the position and posture of the workpiece W so that the extension direction of the linear body, which is the polishing member, roughly coincides with the normal line of the surface of the workpiece W facing it, it becomes possible to suitably polish the surface of the workpiece W while making the brush B conform to the surface of the workpiece W. In this way, by setting the position of the robot arm 20 on the path connecting the target positions, it becomes possible to suitably polish a complex surface having unevenness.

[0067] By setting the target position in this manner and polishing a workpiece W having a complex surface, the workpiece W is polished while its position and posture are frequently changed by the robot arm 20, which is an operation unique to the polishing method of this embodiment.

[0068] The allowable range acquisition unit 10C acquires information indicating an allowable range within which the actual reference position of the robot arm 20 can deviate from the path based on the path of the reference position. For example, when the angle of the link 20L driven by the series elastic actuator 20D is α when the reference position of the robot arm 20 reaches a certain target position, information indicating the allowable range of the link 20L is acquired as angle information, for example, α±β. β is information in angle units that can be preset as the range of elastic deformation based on the elastic modulus of the elastic body 20DE of the series elastic actuator 20D. When the robot arm 20 includes multiple series elastic actuators 20D to have flexibility in multiple directions, the allowable range acquisition unit 10C can acquire information indicating the allowable range for each of the multiple links 20L driven by the series elastic actuator 20D.

[0069] The information indicating the allowable range may be position information indicating a predetermined area that a reference position, which is another part of the robot arm 20, can take as a result of the change in the angle of the link 20L. That is, when the angle of a given link 20L is α+β, the tip of the link 20L is displaced by a distance obtained by multiplying β by the length of the link 20L, and accordingly, the downstream part of the robot arm 20 is also displaced. Therefore, the allowable range acquisition unit 10C may set another part of the robot arm 20 as the reference position and acquire position information indicating a predetermined area that the reference position can take. The following mainly describes the case where the position on the surface of the workpiece W held by the tip link 20L is set as the reference position of the robot arm 20.

[0070] The tolerance is preferably set so as to compensate for any shortening of the linear body due to wear. For example, if the linear body of brush B is set to be replaced when it becomes 5 mm shorter, the tolerance is preferably set so as to allow the reference position to be at least 5 mm away from the path. With such a setting, even if the length of the linear body becomes shorter by wear but not exceeding 5 mm, the workpiece W can be polished so as to compensate for the shortening.

[0071] The information indicating the allowable range can be determined in advance as a constant based on the elasticity or viscosity of the drive mechanism in a computer program stored in the storage unit 10H. Therefore, the control device 10 may be configured so that the arithmetic element of the control device 10 reads out the computer program to obtain the information indicating the allowable range. Alternatively, the control device 10 may obtain the information indicating the allowable range from the teaching device 40.

[0072] The path acquisition unit 10D acquires a path (planned trajectory) connecting the start position and multiple target positions by calculation or the like. Here, the path acquisition unit 10D sets the path so that the polishing member and the member to be polished interfere with each other. In this embodiment, the path is set so that the surface of the workpiece W, which is the member to be polished, passes through an area through which the brush B, which is the polishing member, rotates and passes. By setting the path in this manner, the series elastic actuator 20D of the robot arm 20 can demonstrate its flexibility, making it possible to polish the brush B by conforming it to the surface of the workpiece W.

[0073] However, the path does not need to be set so that the polishing member and the member to be polished always interfere with each other during polishing. For example, when polishing a curved surface on the surface of the member to be polished and then polishing another curved surface, the polishing member and the member to be polished may be temporarily separated from each other.

[0074] The control command acquisition unit 10E acquires, by calculation processing or the like, control commands for controlling each motor for moving the reference position along a path, and supplies the control commands to the robot arm 20. For example, the control command acquisition unit 10E can calculate, by inverse kinematics calculation, the rotation angle of each motor for positioning the reference position on the path, generate a control command based on the calculated rotation angle, and store the control command in the storage unit 10H.

[0075] The polishing member information acquiring unit 10F extracts, for example, the outline of the brush B based on the image information of the brush B received from the imaging device of the robot arm 20, and acquires information indicating the degree of wear of the brush B (sometimes referred to as "amount of wear"). It also acquires information indicating the degree of spread of the linear body of the brush B. When the brush B is composed of many linear bodies, the outline of the brush B varies because the tips of the linear bodies are worn or the linear bodies spread with use. Therefore, the polishing member information acquiring unit 10F can acquire information indicating the degree of wear and spread of the brush B. In addition, when the polishing member is a plate-shaped pad or other polishing member whose appearance changes depending on the amount of use, it is possible to acquire information indicating the amount of wear of the polishing member using the imaging device in the same manner. Furthermore, when polishing multiple types of workpieces W as described above, the polished member information acquiring unit 10G may be configured to be able to identify the type of workpiece W. In that case, the path acquiring unit 10D and the like are configured to acquire a path or the like according to the type of the identified workpiece W.

[0076] The polished member information acquiring unit 10G acquires information for identifying a portion of the workpiece W held by the robot arm 20, for example, by extracting a contour of the workpiece W based on the image information of the workpiece W received from the imaging device 30. In the present embodiment, the runner portion, which is the portion of the workpiece W that will ultimately be removed, is held by the robot arm 20.

[0077] The storage unit 10H stores computer programs (including route generation algorithms) for executing the processes shown in each embodiment, as well as necessary data and other information.

[0078] Regarding the hardware configuration of the control device 10, the control device 10 can be configured from a computer including, for example, a processor such as a central processing unit (CPU) or a graphical processing unit (GPU), a volatile memory such as a static random access memory (SRAM) or a dynamic random access memory (DRAM), a non-volatile memory such as a NOR flash memory, a NAND flash memory, or a hard disk drive (HDD), and a communication means such as a bus connecting these. The non-volatile memory element is a storage medium that stores information non-transitory. The volatile memory element temporarily stores at least a part of these computer programs and the results of the arithmetic processing. The storage unit 10H is configured from these storage elements. In addition, the storage unit 10H functions as a start position acquisition unit 10A, a target position acquisition unit 10B, an allowable range acquisition unit 10C, a path acquisition unit 10D, a control command acquisition unit 10E, a polishing member information acquisition unit 10F, and a polished member information acquisition unit 10G by the computation element executing the computer program stored in the storage unit 10H. However, at least some of these computing elements, non-volatile storage elements, etc. may be installed in a remote location connected to a communication network such as the Internet. For example, the computing element may be configured to obtain a computer program or necessary data via the communication network.

[0079] The control device 10, the robot arm 20, and the imaging device 30 are configured to be able to transmit and receive information to and from each other via wireless or wired communication means.

[0080] The polishing apparatus 100 further includes a teaching device 40. The teaching device 40 may be provided on the robot arm 20, and for example, the input / output unit 20C including a display may be used as a part of the teaching device 40. The teaching device 40 may be configured as a portable teaching pendant for performing online teaching, for example, by actually moving the robot arm 20 on-site and teaching the position and posture at that time as a starting position or a target position. The teaching device 40 includes a calculation element, a volatile storage element, and a non-volatile storage element, similar to the control device 10, and further includes a display means having a display and an input means having a plurality of operation keys and a lever. The input means may be configured as a touch panel type input means for inputting by pressing the display. The teaching device 40 may be a teaching device that follows offline teaching, such as a text type, a simulator type, an emulator type, or an automatic teaching type, in which the position and posture of a reference position are taught as a starting position by a computer program.

[0081] [Metal die-casting product manufacturing method] The method for producing a metal die-cast product according to this embodiment will be described below. First, molding is performed by metal die casting to form a molded product, the workpiece W (step S41). Metal die casting is a process in which metals such as aluminum, zinc, magnesium, copper, etc. are pressed into a die. In this embodiment, metal die casting is performed using a magnesium alloy as the molten metal. Fig. 5(A) shows a schematic configuration of a die 50 exemplified in this embodiment, and Fig. 5(B) shows a cross-sectional view thereof.

[0082] As illustrated in these drawings, the mold 50 includes a movable main mold 50A1 constituting the movable mold and a movable insert 50A2 fitted into the movable main mold 50A1, and a fixed main mold 50B1 constituting the fixed mold and a fixed insert 50B2 fitted into the fixed main mold 50B1. The fixed main mold 50B1 is provided with a casting port bush 50C for pouring molten metal into the mold cavity. The movable main mold 50A1 is provided with a diverter 50D for directing the molten metal poured from the casting port bush 50C to the product portion. In the gap between the fixed mold and the movable mold, a gate runner GR for guiding the molten metal into the mold cavity C that becomes the product portion, the mold cavity C that becomes the product portion, and a gate G connecting the gate runner GR and the mold cavity C are provided. In addition, a plurality of overflow gates, overflows OF, and air vents OB are provided for discharging the molten metal containing gases, oxides, etc., so that it does not remain in the product portion when filled. The workpiece W, which is a molded product formed in this manner, comprises a product portion that will be the final product and a runner portion that remains on the gate runner GR. In addition, many burrs are formed on the workpiece W.

[0083] Next, the conveyor C1 (FIG. 1) transports the workpiece W (step S42). The workpiece W is cooled while being transported. When the conveyor C1 stops transporting the workpiece W at a predetermined position, the imaging device 30 captures an image of the workpiece W and transmits image information of the workpiece W to the control device 10. The polished member information acquisition unit 10G of the control device 10 acquires information indicating the outline of the workpiece W on the conveyor C1, etc., based on the received image information of the workpiece W (step S43).

[0084] The start position acquisition unit 10A of the control device 10 acquires information indicating the outline of the workpiece W on the conveyor C1 from the polished member information acquisition unit 10G, and based on this, acquires the position (including the posture) of the robot arm 20 at the time of starting to hold the workpiece W as the start position. Note that when the conveyor C1 transports multiple types of workpieces W, the start position acquisition unit 10A may be configured to acquire information identifying the type of workpiece W from the polished member information acquisition unit 10G and hold different parts of the workpiece W depending on the type of workpiece W.

[0085] Furthermore, the target position acquisition unit 10B and the allowable range acquisition unit 10C acquire information indicating one or more target positions and information indicating the allowable range, respectively (step S44). However, the control device 10 may acquire this information by reading it from the storage unit 10H that stores this information in advance, or may acquire this information from the teaching device 40. Furthermore, when acquiring a path by calculation based on the information indicating the start position and the information indicating the target position, the control device 10 may acquire information indicating the allowable range by reading out a path generation algorithm that keeps the distance between the object surface and the reference position within the allowable range, and acquiring a path based on this.

[0086] Next, the control command acquisition unit 10E acquires a control command for the series elastic actuator 20D based on the path information (step S45). When the control commands for realizing a series of operations are stored in advance in the storage unit 10H, the control device 10 may acquire the information by reading the control commands from the storage unit 10H.

[0087] Next, the robot arm 20 drives each link 20L based on the control command received from the control device 10. First, the robot arm 20 moves to the start position, holds the runner portion of the workpiece W on the conveyor C1, and starts the movement of the workpiece W (step S46).

[0088] Next, the imaging device mounted on the input / output unit 20C of the robot arm 20 captures an image of the brush B, which is the member to be polished, and obtains image information of the brush B (step S47).

[0089] The polishing member information acquisition unit 10F of the control device 10 extracts the outline of brush B based on image information of brush B to acquire information indicating the degree of wear and the degree of spread of brush B. If the amount of wear of brush B is large or brush B has spread too much to be suitable for polishing, the polishing member information acquisition unit 10F causes the input / output unit 20C to issue a warning indicating that it is time to replace brush B. Note that this step may be executed at a different timing. For example, this step may be executed after polishing is completed.

[0090] If it is determined that the brush B is suitable for polishing, the brush B starts to rotate (step S48). In this embodiment, the brush B is installed on a rotary drive device such as a drill press or a machining center so that the tip of the brush B faces vertically. However, the brush B may be held by a separate robot arm and rotated. In this case, it is preferable to use a normal, highly rigid robot arm that does not have flexibility, unlike the robot arm 20, as the robot arm that holds the brush B. By moving the brush B while rotating it using such a robot arm, polishing may be performed by making the brush B conform to the surface of the workpiece W held by the robot arm 20 having a flexible drive mechanism.

[0091] FIG. 6(A) shows the brush B in a stationary state. As shown in the figure, the brush B according to this embodiment has a cylindrical shaft portion and a number of filamentous bodies planted on the bottom surface of the shaft portion. Each filamentous body is formed in a linear, i.e., elongated, shape. The filamentous bodies are made of a material suitable for polishing the member to be polished. Experiments by the inventors of the present application have revealed that when the member to be polished is a magnesium alloy, deposits can be suitably removed by making the filamentous bodies out of brass.

[0092] Since each linear body is formed long and thin, it is possible for the tip of the linear body to reach steps, gaps, recesses, etc. It is also possible for the tip of the linear body to reach areas that are difficult to polish with a plate-shaped polishing member because burrs and the like are formed and become obstacles.

[0093] With the brush B rotating in this state, the robot arm 20 brings the workpiece W close and brings it into contact with the brush B, thereby starting polishing the surface of the workpiece W (step S49).

[0094] 6(B) and (C) are enlarged views showing a state in which the tip of the linear body of the rotating brush B is polishing a recessed portion on the surface of the workpiece W, which is a member to be polished. For the sake of simplicity, the link 20L and the end effector 20L1 at the tip of the robot arm 20 that holds the workpiece W are omitted from the drawings. Also, the number of linear bodies of the brush B is depicted as being smaller than it actually is.

[0095] 6B, the dashed line L1 indicates the surface of the workpiece W when the reference position is on the planned path in the absence of the brush B. The solid line L2 indicates the surface of the workpiece W in the presence of the brush B.

[0096] As indicated by the dashed line L1, when the reference position is on the path (including the target position), the surface of the workpiece W interferes with the brush B. However, in reality, the brush B exists and is pressed against the surface of the workpiece W, making it possible to polish the workpiece W by making the brush B conform to the surface of the workpiece W.

[0097] Here, the displacement amount D1 corresponding to the distance between the dashed line L1 and the solid line L2 (i.e., the distance between the reference position on the planned path and the actual reference position) corresponds to the amount of elastic deformation of the elastic bodies 20DE of the multiple series elastic actuators 20D.

[0098] Therefore, a force generated based on the elastic modulus and displacement D1 of the elastic body 20DE acts from the workpiece W to the brush B, and a reaction force acts from the brush B to the workpiece W. For this reason, by setting the target position and path so as to remove deposits on the surface of the workpiece W and to apply a force that does not damage the surface of the workpiece W, it becomes possible to perform polishing with an appropriate force.

[0099] Here, if the displacement amount D1 is too large, it will damage the surface of the workpiece W. Therefore, as will be described later, a permissible range is set so that the displacement amount D1 does not become too large.

[0100] Based on a control command from the control device 10, the robot arm 20 moves the workpiece W along a path set so that the surface of the workpiece W interferes with the brush B, thereby causing the surface of the workpiece W to follow the brush B and continue polishing (step S50). During this time, the control device 10 periodically obtains the magnitude of the load using a sensor provided in the series elastic actuator 20D, and performs polishing while maintaining the force acting from the brush B on the surface of the workpiece W within a substantially constant range.

[0101] Fig. 6(C) is an enlarged view showing a state where another part of the recess on the surface of the workpiece W is being polished. Note that explanations of the dashed line L1 and the solid line L2 will be omitted since they have the same meaning as in Fig. 6(B). As shown in Fig. 6(C), the robot arm 20 changes the position and posture of the workpiece W so that the surface to be polished faces generally upward even when polishing the same recess.

[0102] Note that the displacement amount D1 shown in Fig. 6(B) and the displacement amount D2 shown in Fig. 6(C) are not necessarily the same. For example, if burrs or the like are formed around the surface to be polished, some of the linear bodies do not reach the surface of the workpiece W, and the force acting from the brush B to the workpiece W becomes smaller. Since the robot arm 20 has a driving mechanism with flexibility for multiple axes, in such a case, it is configured to be able to move the workpiece W in a direction in which the displacement amount becomes smaller so as to compensate for the reduction in the force acting from the brush B to the workpiece W. Therefore, in that case, the displacement amount D2 becomes smaller than the displacement amount D1.

[0103] Conversely, for example, depending on the direction of the surface to be polished, the force acting from the brush B to the workpiece W increases. In such a case, the robot arm 20 is configured to be able to move the workpiece W in a direction in which the displacement amount increases so as to compensate for the increase in the force acting from the brush B to the workpiece W. Therefore, in that case, the displacement amount D2 becomes larger than the displacement amount D1.

[0104] Here, since each linear body of the brush B is formed long and thin, even if the tip of some of the linear bodies hits the workpiece W, if the force acting from the brush B to the workpiece W is small, it is possible to displace the workpiece W so that the distance between the brush B and the workpiece W becomes smaller. When the distance between the brush B and the workpiece W becomes smaller, the force that the workpiece W receives from the brush B becomes larger, so that it becomes possible to polish the workpiece W with a force suitable for polishing.

[0105] The control device 10 controls the robot arm 20 so that the amount of displacement falls within an allowable range and the force acting from the brush B to the workpiece W is substantially constant or within a substantially constant range (for example, within an average value ±50%). In order to keep the amount of displacement within the allowable range, the control device 10 periodically determines whether or not a displacement exceeding the allowable range has occurred (step S51).

[0106] If the control device 10 determines that a displacement exceeding the allowable range has occurred (NO), the control device 10 generates a control command to slow down the movement speed of the robot arm 20 and sends it to the drive section of the robot arm 20, thereby slowing down the robot arm 20 and the workpiece W held by it (step S52).

[0107] FIG. 7 is a graph for explaining the deceleration operation when the allowable range is exceeded during the tracing operation. In this graph, the horizontal axis represents time and the vertical axis represents the angle of the link 20L driven by the series elastic actuator 20D. In this graph, the target link 20L has an angle α1 at time t1 as a first target position, an angle α2 at time t2 as a second target position, and a path P (planned trajectory) is set in which the angle changes with time. The allowable range based on the path of this link 20L is ±β1 centered on the angle of the link 20L. In this graph, the actual angle change is indicated by a solid line A.

[0108] As shown in this graph, when the angle of the link 20L becomes outside the allowable range based on the path P at time t11, the control device 10 reduces the rotation speed of the link 20L and the moving speed of the workpiece W, as described above, to control the angle of the link 20L to fall within the allowable range. On the other hand, the angle of the link 20L falls within the allowable range between time t11 and time t2. Therefore, the control device 10 does not perform control to move the solid line A closer to the path P. Therefore, even if the relative positional relationship between the workpiece W and the brush B fluctuates depending on the surface shape of the workpiece W, the relative positional relationship can be maintained to follow the change, and polishing can be continued.

[0109] FIG. 8 is a schematic diagram showing how the surfaces of convex portions (hereinafter referred to as "convex surfaces") on the surfaces of different types of workpieces W are polished. As with FIG. 6, the end effector 20L1 and the like are omitted from the diagram for the sake of simplicity. The arrow in this diagram indicates the relative movement direction of the brush B with respect to the workpiece W. Conventionally, it has been difficult to move the polishing member relatively to follow such a convex surface. In addition, the relative positional relationship between the polishing member and the workpiece to be polished varies due to individual differences (including burrs) during molding, making polishing such a convex surface even more difficult.

[0110] The robot arm 20 of the polishing apparatus 100 according to this embodiment has a flexible drive mechanism, so it is possible to move the workpiece W so as to avoid the convex portion while compensating for fluctuations in the relative positional relationship between the convex surface of the workpiece W and the brush B. Therefore, even if a path is set as shown by the arrow according to an ideal shape of the convex portion, in reality, it is possible to relatively move the workpiece W and the brush B in accordance with the shape of the workpiece W and the brush B, rather than following the path. Therefore, even if a member to be polished has a complex surface, it is possible to polish the workpiece W and the brush B appropriately.

[0111] It is not necessary to continue polishing the polished member and the polishing member by always following the surface of the polished member with the polishing member. For example, a part of the surface of the polished member may not be polished. There may also be a timing when the polished member and the polishing member are separated. Furthermore, a part of the surface may be polished by a different polishing method. Furthermore, a part of the surface may be polished with a different tolerance. For example, the tolerance may be set to be small in order to increase the polishing accuracy of the surface exposed to the outside.

[0112] When it is determined that the workpiece W has reached the final target position (YES), the polishing by the polishing apparatus 100 is completed (step S53).

[0113] Thereafter, a coating material is applied to the surface of the workpiece W by an application device capable of discharging the coating material (step S54). Since magnesium alloys are easily corroded, applying a coating material after polishing makes it possible to improve the corrosion resistance of the workpiece W. The robot arm 20, while holding the workpiece W, moves the workpiece W while changing its position and posture so as to face the nozzle of the application device, thereby making it possible to apply the coating material to the surface of the workpiece W. Note that application may be performed by the same or similar operation as during polishing, by aligning the direction in which the tip of the brush B faces (vertical direction) with the direction in which the coating material is discharged.

[0114] When application of the coating material is completed, the robot arm 20 places the workpiece W on the conveyor C2 and releases the hold of the workpiece W (step S55).

[0115] Thereafter, burrs, runners, and the like remaining on the workpiece W are removed by a burr removal die (step S56). Through such a process, a metal die-cast product is manufactured.

[0116] As described above, the polishing apparatus 100 and polishing method according to this embodiment make it possible to suitably polish even a workpiece having a complex surface.

[0117] In this embodiment, the robot arm 20 is configured to hold the workpiece W rather than the polishing member, the brush B. Therefore, the process in which an operator polishes a workpiece by pressing it against a rotating polishing member can be easily replaced with the polishing method according to this embodiment.

[0118] However, as described above, the brush B may be held by a rigid robot arm on one hand and the workpiece may be held by a flexible robot arm on the other hand, and the polishing may be performed by rotating the brush B to conform to the workpiece W.

[0119] Furthermore, as illustrated in FIG. 2(B), the brush B may be held by the robot arm 20 shown in this embodiment, and an actuator for rotating the brush B may be mounted on an end effector or the like, so that the brush B held by the robot arm 20 can be rotated to conform to the surface of the workpiece W while polishing.

[0120] Further, the workpiece W according to the present embodiment is a metal die-cast product, but is not limited to this. For example, a resin molded product may be used as the workpiece to be polished.

[0121] In addition, the present invention can be modified in various ways without departing from the spirit of the present invention. For example, some components in one embodiment can be added to other embodiments within the scope of ordinary creativity of a person skilled in the art. Also, some components in one embodiment can be replaced with corresponding components in other embodiments. [Explanation of symbols]

[0122] 10 Control device 10A Start position acquisition part 10B Target position acquisition section 10C Tolerance range acquisition section 10D Route acquisition section 10E Control command acquisition unit 10F Polishing material information acquisition section 10G Polished member information acquisition section 10H storage section 20 Robot Arm 20A Drive Unit 20C input / output section 20D Series Elastic Actuator 20DA Drive Unit 20DE Elastic body 20J Joint 20L Link 20L1 End effector 30 Imaging device 40 Teaching device 50 Mold 100 Polishing equipment B Brush W work

Claims

1. A step of setting a path of a reference position of a robot arm having a flexible drive mechanism such that a polishing member and a polished member interfere with each other; A permissible range within which the deceleration operation of the robot arm is executed when the reference position of the robot arm deviates from the path based on the path is set. A step of setting and polishing the surface of the workpiece by rotating the polishing member held by the robot arm so as to conform to the surface of the workpiece, The polished member is a metal die-cast product. Polishing method.

2. A step of setting a path of a reference position of a robot arm having a flexible drive mechanism such that a polishing member and a polished member interfere with each other; setting an allowable range within which a deceleration operation of the robot arm is executed when a reference position of the robot arm deviates from the path, based on the path; and polishing the surface of the workpiece held by the robot arm by following the rotating polishing member, The polished member is a metal die-cast product. Polishing method.

3. The step is carried out while maintaining the force acting from the polishing member on the surface of the workpiece within a substantially constant range. The polishing method according to claim 1 or 2.

4. The polished member is made of a magnesium alloy. The polishing method according to claim 1 .

5. The polishing member is made of brass. The polishing method according to claim 1 .

6. 6. The polishing method according to claim 1, wherein the robot arm has a plurality of drive shafts, and each of the plurality of drive shafts is provided with a series elastic actuator as the flexible drive mechanism.

7. 7. The polishing method according to claim 1, further comprising the step of applying a coating material to the surface of the workpiece using the robot arm after the polishing step.

8. The polishing method according to claim 1 , wherein the polishing member is a buff or a brush.

9. performing a metal die casting; a step of carrying out the polishing method according to claim 1 or 2, using the metal die-cast product formed in the step as the polished member; A method for producing a metal die-cast product comprising the steps of:

10. The method for manufacturing a metal die-cast product according to claim 9, further comprising the step of removing flash and a runner portion of the metal die-cast product formed by the metal die casting.

11. a robot arm having a flexible drive mechanism and configured to be able to hold a polishing member; A path of a reference position of the robot arm is set so that the polishing member and the workpiece interfere with each other; setting an allowable range within which a deceleration operation of the robot arm is executed when a reference position of the robot arm deviates from the path based on the path; The polishing member is configured to polish the surface of the workpiece while rotating, and the polishing member is configured to conform to the surface of the workpiece, The polished member is a metal die-cast product. Polishing equipment.

12. a robot arm having a flexible drive mechanism and configured to be capable of holding a member to be polished; A path of a reference position of the robot arm is set so that the polishing member and the polished member interfere with each other; setting an allowable range within which a deceleration operation of the robot arm is executed when a reference position of the robot arm deviates from the path based on the path; The surface of the workpiece is polished by following the rotating polishing member, The polished member is a metal die-cast product. Polishing equipment.

13. A control device for controlling a robot arm having a flexible drive mechanism and a holding mechanism capable of holding a polishing member, setting a path of a reference position of the robot arm such that the polishing member and the workpiece interfere with each other; setting an allowable range within which a deceleration operation of the robot arm is executed when a reference position of the robot arm deviates from the path, based on the path; a step of rotating the polishing member by using the robot arm to conform to the surface of the workpiece; is configured to be executable, The polished member is a metal die-cast product. Control device.

14. A control device for controlling a robot arm having a flexible drive mechanism and a holding mechanism capable of holding a member to be polished, Setting a path of a reference position of the robot arm such that a polishing member and the polished member interfere with each other; setting an allowable range within which a deceleration operation of the robot arm is executed when a reference position of the robot arm deviates from the path, based on the path; a step of polishing the surface of the workpiece by using the robot arm to follow the rotating polishing member; is configured to be executable, The polished member is a metal die-cast product. Control device.

15. A step of setting a path of a reference position of a robot arm having a flexible drive mechanism such that a polishing member and a polished member interfere with each other; setting an allowable range within which a deceleration operation of the robot arm is executed when a reference position of the robot arm deviates from the path, based on the path; a step of polishing the surface of a workpiece by rotating the polishing member using the robot arm having a holding mechanism capable of holding the polishing member, and aligning the polishing member with the surface of a workpiece; generating control instructions for operating the robot arm by a computer to perform the steps of: The polished member is a metal die-cast product. Computer program.

16. A step of setting a path of a reference position of a robot arm having a flexible drive mechanism such that a polishing member and a polished member interfere with each other; setting an allowable range within which a deceleration operation of the robot arm is executed when a reference position of the robot arm deviates from the path, based on the path; a step of polishing a surface of the polished member by using the robot arm having a holding mechanism capable of holding the polished member, so as to follow a rotating polishing member; generating control instructions for operating the robot arm by a computer to perform the steps of: The polished member is a metal die-cast product. Computer program.

Images