Robotic machining equipment and machining method

Abstract

To provide a machining center that reduces the processing load on the workpiece. [Solution] The robotic machining machine 10 for machining workpiece 1 comprises a robotic arm 13a, an end effector 15 positioned at the tip of the robotic arm 13a, the end effector 15 having a spindle 24 on which a tool 27 can be attached and a spindle motor 25 that rotates the spindle 24, an end effector marker 21 positioned on the end effector 15, and an external position measuring device 39 positioned at a distance from the robotic arm 13a to measure the position of the end effector marker 21.

Description

Technical Field

[0001] The present invention relates to a robotic processing machine and a processing method.

Background Art

[0002] There is known a processing machine having a movable platform, a platform control device, a position detector, and a robot (EP2353801A2, hereinafter referred to as Patent Document 1). The robot has a robot head and a processing head for processing a workpiece, and is disposed on the platform. The processing head has a support strut for holding the workpiece and a drill tool that is drivable and held in a telescopic manner. Since the processing head of Patent Document 1 is large, a large robot is required. Since there is a support strut around the drill, the processing head cannot be inserted into a narrow portion. Further, since the processing head adheres or sticks to the workpiece, a processing load is applied to the workpiece.

Summary of the Invention

Problems to be Solved by the Invention

[0003] When processing with a processing head having no support strut using a robot, the arm of the robot tends to bend due to the processing reaction force. The bending of the arm may vary depending on the installation condition of the workpiece and the state of the tool. Further, the bending of the arm may change over time. As a result, the dimensions and surface roughness of the processed workpiece change. An object of the present invention is to record the bending of the arm and the processing condition when processing with a processing head disposed at the tip of the arm and having no support strut.

Means for Solving the Problems

[0004] A first aspect of the present invention is a robotic processing machine for processing a workpiece, a robot arm, and an end effector disposed at the tip of the robot arm, A spindle to which tools can be attached, The spindle motor rotates the aforementioned spindle, An end effector having, The end effector marker placed on the end effector, An external position measuring device is positioned at a distance from the robot arm and measures the position of the end effector marker. It is a robotic machining center equipped with [a specific feature / ability].

[0005] A second aspect of the present invention is, The spindle, to which the tool is mounted, rotates, and the end effector positioned at the tip of the robot arm processes the workpiece. An external position measuring instrument measures the end effector spatial coordinates of the end effector marker of the end effector during machining. The position of the end effector is determined. This is a processing method.

[0006] The end effector may have a second feed axis (X-axis) perpendicular to the main spindle and parallel to the flange surface. Multiple end effector markers may be placed. The recording device may record the positions of multiple end effector markers. An external position measuring instrument may detect the orientation of the end effector markers. The recording device may record the orientation of the end effector markers over time. External position measuring devices include, for example, optical cameras and laser trackers. Multiple external position measuring devices may be deployed. Position markers include, for example, 3D shape markers, AR markers, targets, reflectors, and SMRs.

[0007] The end effector may have a body. The end effector marker may be positioned on the body. A thermometer may be placed on the frame or support columns. The thermometer will measure the temperature in the robot's operating area. The robot may have robot thermometers placed on each axis. The robot thermometers measure the temperature of each part of the robot arm. The robot thermometers may be placed on each axis. The end effector may have an end effector thermometer. The end effector thermometer measures the temperature of the spindle and the body of the end effector. The memory unit may also store ambient temperature, workpiece temperature, and robot temperature over time. [Effects of the Invention]

[0008] According to the present invention, when machining is performed by a machining head positioned at the tip of the arm and without a support strut, the deflection of the arm and the machining status can be measured. [Brief explanation of the drawing]

[0009] [Figure 1] Robot processing machine of Embodiment 1 [Figure 2] End effector of Embodiment 1 [Figure 3] Control device of Embodiment 1 [Figure 4] Robotic machining machine of Embodiment 2 [Modes for carrying out the invention]

[0010] <Embodiment 1> As shown in Figure 1, the robotic machining center 10 of this embodiment includes a frame 11, a robot 13, an end effector 15, a table 31, a support column 35, a safety fence 37, multiple cameras 39, a control device 41, a room thermometer 38, a workpiece thermometer 34, and a coolant device 12.

[0011] The frame 11 supports the table 31, the robot 13, the support column 35, and the thermometer 38. The robot 13 is a vertical articulated robot. The robot 13 has an arm 13a, a flange 13b, a motor (joint motor) 13c, a rotary encoder 13d, and a robot thermometer 13f. The flange 13b is arranged at the tip of the arm 13a. The motor 13c and the rotary encoder 13d are arranged on each axis of the arm 13a. The rotary encoder 13d may be arranged on the motor 13c. The rotary encoder 13d is, for example, a rotary encoder or a resolver. The robot thermometer 13f may be arranged on each axis. The end effector 15 is arranged on the flange 13b and is moved by the arm 13a. The end effector 15 has an end effector marker 21. The end effector marker 21 is an optical marker and is, for example, in a polyhedron shape.

[0012] The table 31 has a support base 31a and a clamping device (not shown). The support base 31a supports the workpiece 1. The clamping device fixes the workpiece 1 to the table 31. The workpiece 1 has a workpiece marker 33. The workpiece marker 33 is substantially the same as the end effector marker 21. The workpiece thermometer 34 is arranged on the table 31. The workpiece thermometer 34 may be arranged on the support base 31a. The workpiece thermometer 34 measures the temperature of the workpiece 1.

[0013] A plurality of columns 35 are arranged substantially evenly on the periphery of the frame 11. The columns 35 support the safety fence 37 and the camera 39. The safety fence 37 is, for example, a wire mesh, a metal plate, or a plastic plate.

[0014] The room thermometer 38 measures the atmospheric temperature inside the safety fence 37. The coolant device 12 is arranged outside the frame 11. The coolant device 12 has a coolant thermometer 12a. Note that the coolant device 12 may be arranged outside the robot processing machine 10.

[0015] A plurality of cameras 39 are arranged at the upper ends of the columns 35. The cameras 39 photograph the end effector marker 21 and the workpiece marker 33.

[0016] As shown in FIG. 2, the end effector 15 has a body 17, a linear guide 20, a ram 23, a spindle 24, a connection block 22, a feed screw 18, a spindle motor 25, a feed motor 19, and an end effector thermometer 26.

[0017] The body 17 is box-shaped. The body 17 has a ram hole 17a. The linear guide 20 is disposed on the body 17 and extends in the Z direction. The connection block 22 is disposed on the linear guide 20. The connection block 22 is guided by the linear guide 20 and reciprocates in the Z direction. The ram 23 passes through the ram hole 17a and is connected to the connection block 22. The ram 23 is guided by the ram hole 17a. The end effector marker 21 is disposed on the body 17.

[0018] The spindle 24 is rotatably supported by the ram 23. A tool 27 is attached to the spindle 24. The spindle motor 25 is disposed on the body 17 and connected to the spindle 24. The spindle motor 25 rotates the spindle 24. The feed screw 18 extends in the Z direction and is rotatably supported by the body 17. The feed screw 18 moves the connection block 22. The feed motor 19 is disposed on the body 17 and connected to the feed screw 18. The feed motor 19 rotates the feed screw 18 to feed the spindle 24 in the Z direction. A plurality of end effector thermometers 26 may be disposed. The end effector thermometer 26 is disposed, for example, on the ram 23. The end effector thermometer 26 measures the temperature of the spindle 24. The end effector thermometer 26 may measure the temperature of the body 17. Note that the end effector 15 may have a linear motor instead of the feed motor 19 and the feed screw 18.

[0019] As shown in FIG. 3, the control device 41 has a storage unit 43, a robot control unit 53, an end effector control unit 55, a correction unit 57, a coordinate determination unit 59, a work temperature 61, and an ambient temperature 63. Note that the correction unit 57 may be omitted.

[0020] The memory unit 43 consists of an external memory device and a main memory device. The memory unit 43 may also be included in the robot control unit 53 and the end effector control unit 55. The memory unit 43 stores the robot output 45, the end effector output 47, the end effector spatial coordinates 49, the workpiece spatial coordinates 51, the workpiece temperature 61, the ambient temperature 63, and a machining program (not shown). The machining program includes the machining program for the robot 13 and the machining program for the end effector 15.

[0021] The robot output 45 includes the torque 45a for each axis, the angular velocity 45b for each axis, the tip coordinate 45c, and the temperature 45d for each axis. The torque 45a for each axis is the output torque of the motor 13c for each axis of the robot 13. The angular velocity 45b for each axis is the rotational speed of each joint of the robot 13. The tip coordinate 45c is the position coordinate of the flange 13b with respect to the workpiece reference 1a. The tip coordinate 45c is the coordinate of the flange 13b being output by the robot 13. The torque 45a for each axis, the angular velocity 45b for each axis, and the tip coordinate 45c are recorded over time with respect to the time or elapsed time since the start of operation.

[0022] The end effector output 47 includes spindle torque 47a, spindle speed 47b, feed axis torque 47c, feed axis speed 47d, spindle coordinates 47e, tool information 47f, and end effector temperature 47g. Spindle torque 47a is the output torque of the spindle motor 25. Spindle speed 47b is the rotational speed of the spindle 24. Feed axis torque 47c is the output torque of the feed motor 19. Feed axis speed 47d is the feed rate of the spindle 24 and ram 23. Spindle coordinates 47e are the coordinates of the spindle 24 from the machine origin 15a of the end effector 15. Tool information 47f is information about the tool 27. Tool information 47f may include, for example, tool number, tool type, tool length, tool diameter, and tool usage time. The spindle torque 47a, spindle speed 47b, feed axis torque 47c, feed axis speed 47d, spindle coordinates 47e, and tool information 47f are recorded over time with respect to the time of day or the elapsed time since the start of operation.

[0023] The end effector spatial coordinates 49 are the coordinates of the end effector 15 in three-dimensional space calculated by the coordinate determination unit 59. The end effector spatial coordinates 49 include the left-right direction (X direction), front-back direction (Y direction), up-down direction (Z direction), rotational direction around the X direction (A direction), rotational direction around the Y direction (B direction), and rotational direction around the Z direction (C direction) of the end effector 15. The end effector spatial coordinates 49 are the coordinates of the reference position 13e of the flange 13b with respect to the reference point 2 of the machining space. The reference point 2 is, for example, the center of the first axis on the installation surface of the robot 13. The end effector spatial coordinates 49 are recorded over time with respect to the time or elapsed time since the start of operation.

[0024] The work space coordinates 51 are the coordinates of workpiece 1 in three-dimensional space. The work space coordinates 51 are the coordinates of workpiece reference 1a, relative to reference point 2. The work space coordinates 51 include coordinates in the X, Y, Z, A, B, and C directions. The work space coordinates 51 are recorded over time with respect to the time or elapsed time since the start of operation.

[0025] The workpiece temperature 61 is the temperature of workpiece 1. The workpiece temperature 61 is stored over time with respect to the time of day or the elapsed time since the start of operation by the workpiece thermometer 34. The ambient temperature 63 includes the ambient temperature and the coolant temperature. The ambient temperature 63 is stored over time with respect to the time of day or the elapsed time since the start of operation by the room thermometer 38 and the coolant thermometer 12a.

[0026] The robot control unit 53 numerically controls the robot 13. The robot control unit 53 stores the output values ​​of the motors 13c of each axis, the rotation angle meter 13d, and the tip coordinates of the flange 13b in the memory unit 43. The robot control unit 53 operates the robot 13 based on the robot machining program. The robot control unit 53 may perform thermal compensation for the robot 13 based on the temperature 45d of each axis and the ambient temperature 63.

[0027] The end effector control unit 55 numerically controls the end effector 15. The end effector control unit 55 stores the load of the spindle 24, the rotational speed, coordinates, the load of the feed motor 19, and tool information 47f in the storage unit 43. The end effector control unit 55 operates the end effector 15 based on the end effector machining program. The end effector control unit 55 may perform thermal compensation for the end effector 15 based on the end effector temperature 47g and the ambient temperature 63.

[0028] The coordinate determination unit 59 calculates the end effector spatial coordinates 49 from the image of the end effector marker 21 captured by the camera 39 and stores them in the memory unit 43. The coordinate determination unit 59 continuously calculates the end effector spatial coordinates 49 while the end effector 15 is processing the workpiece 1.

[0029] The correction unit 57 reads the end effector spatial coordinates 49, the workpiece spatial coordinates 51, and the tip coordinates 45c from the storage unit 43. The correction unit 57 calculates the coordinates of the end effector 15 relative to the actual workpiece reference 1a from the end effector spatial coordinates 49 and the workpiece spatial coordinates 51. The coordinates of the end effector 15 at the output of the robot 13 are the tip coordinates 45c. The command value of the tip coordinates 45c is the target value r. The correction unit 57 calculates the difference e between the end effector spatial coordinates 49 and the target value r. The correction unit 57 calculates a correction amount S from the difference e and transmits it to the robot control unit 53 or the end effector control unit 55. The correction unit 57 may also allocate the correction amount S to a robot correction amount S1 and an end effector correction amount S2. The robot control unit 53 adds the robot correction amount S1 received from the correction unit 57 to the command value of the tip coordinates 45c. The end effector control unit 55 adds the end effector correction amount S2 received from the correction unit 57 to the command value of the main axis coordinate 47e. This corrects the positions of the arm 13a and the end effector 15.

[0030] The robotic machining center 10 is operated based on commands from the control device 41. The robot 13 moves the end effector 15 so that the spindle 24 is facing the workpiece 1 and close to it. The end effector 15 then rotates the spindle 24. Next, the end effector 15 feeds out the ram 23 to bring the tool 27 into contact with the workpiece 1. When drilling holes or tapping, the end effector 15 feeds back the ram 23 when it reaches a predetermined depth. When milling, the robot 13 moves the end effector 15 laterally relative to the spindle 24.

[0031] When the tool 27 cuts the workpiece 1, the spindle 24 and the robot 13 receive cutting reaction forces from the workpiece 1. The robot 13 may not have sufficient rigidity against the cutting reaction forces that the end effector 15 receives from the workpiece 1. Therefore, the arm 13a may bend due to gravity and cutting reaction forces acting on the end effector 15. In this case, the position coordinates of the flange 13b in real space will differ from the tip coordinates 45c.

[0032] The size of workpiece 1, its installation position, the rigidity and deflection of arm 13a, the cutting edge condition of tool 27, the frictional resistance of end effector 15, and backlash all change slightly with each machining operation. These factors can cause variations in the machining accuracy and surface roughness of workpiece 1. Measuring the machining accuracy of workpiece 1 after processing is time-consuming. Furthermore, during machining, the robot 13 is subjected to a vibrating load, which can increase the play in the joints of arm 13a, potentially reducing positional accuracy.

[0033] The memory unit 43 of this embodiment records the torque 45a of each axis, the angular velocity 45b of each axis, the tip coordinate 45c, the spindle torque 47a, the feed axis torque 47c, the feed axis speed 47d, the spindle coordinate 47e, the temperature 45d of each axis, the end effector temperature 47g, the workpiece temperature 61, and the ambient temperature 63 as needed. According to the machining machine 10 of this embodiment, by recording the load and coordinate values ​​during machining, it is possible to analyze the points of change in the machining machine 10. For example, when the fluctuation of a particular value becomes extremely large, or when the fluctuation trend of the value in a previous machining operation differs from that of the most recent machining operation, it is possible to obtain a precursor to a change in the machining accuracy of the workpiece 1.

[0034] Furthermore, when the camera 39 photographs the end effector marker 21, the coordinate determination unit 59 determines the end effector spatial coordinates 49. If the end effector spatial coordinates 49 during the current machining process show a different trend from the end effector spatial coordinates 49 during previous machining processes, it is possible to obtain a prediction of a change in the machining accuracy of the workpiece 1. The change in the work space coordinate 51 is substantially the same as the change in the end effector space coordinate 49.

[0035] The correction unit 57 determines the position of the flange 13b as observed from the outside, using the end effector spatial coordinates 49 and the workpiece spatial coordinates 51. On the other hand, the tip coordinates 45c are the position of the flange 13b as observed from inside the robot 13. The correction unit 57 feeds back the difference between the externally observed position of the flange 13b and the tip coordinates 45c to the robot control unit 53 and the end effector control unit 55, thereby correcting the commands for the robot 13 and the end effector 15. As a result, the robot machining center 10 can machine the workpiece 1 based on the coordinates actually observed from the outside.

[0036] <Embodiment 2> As shown in Figure 4, the robotic machining center 100 of this embodiment includes a frame 11, a slide axis 71, a robot 13, a slide-type end effector 115, a table 31, a support column 35, a safety fence 37, a robot position marker 79, a plurality of cameras 39, and a control device 141.

[0037] The slide shaft 71 comprises a slide frame 73, a slider 74, a slide motor 75, and a lead screw 77. The slide frame 73 is positioned on the frame 11 and extends along the X-axis. The slider 74 is guided by the slide frame 73 and reciprocates within the slide frame 73 along the X-axis. The lead screw 77 extends along the X-axis and is rotatably supported on the frame 11. The slide motor 75 is positioned on the frame 11. The slide motor 75 is connected to the lead screw 77. The slide motor 75 rotates the lead screw 77, thereby driving the slider 74. Note that the lead screw 77 may be replaced with a nut-rotating lead screw or a rack and pinion.

[0038] Robot 13 is positioned on slider 74. The robot position marker 79 is placed on the slider 74.

[0039] The sliding end effector 115 has an X slider 129 and a spindle unit 128. The X slider 129 has an X frame 130, an X motor 132 and a lead screw 134. The X frame 130 is positioned on the flange 13b. The X frame 130 extends along the X axis. The spindle unit 128 is substantially identical to the end effector 15 of Embodiment 1. The spindle unit 128 is guided by the X frame 130 and reciprocates in the X direction. The lead screw 134 extends along the X axis and is rotatably positioned on the X frame 130. The X motor 132 is positioned on the X frame 130. The X motor 132 is connected to the lead screw 134. The X motor 132 rotates the lead screw 134, moving the spindle unit 128 in the X direction. The end effector marker 21 is positioned on the spindle unit 128 and the X-frame 130.

[0040] The control device 141 includes a storage unit 143, a slide axis control unit 60, a robot control unit 53, an end effector control unit 155, a correction unit 57, and a coordinate determination unit 59. The memory unit 143 stores the slide axis output 65, the robot output 45, the end effector output 47, the end effector spatial coordinates 49, the workpiece spatial coordinates 51, and the robot spatial coordinates 52. The slide axis output 65 includes the slide axis torque 65a and the slide axis speed 65b. The slide axis output 65 may also include the X coordinate (not shown) of the slide axis 71. The robot spatial coordinate 52 is the coordinate of the reference point 2 relative to the frame.

[0041] Similar to Embodiment 1 shown in Figure 3, the end effector output 47 includes the feed axis torque 47c, the feed axis speed 47d, and the spindle coordinates 47e. The feed axis torque 47c includes the torque of the X motor 132. The feed axis speed 47d includes the speed in the X direction. The spindle coordinates 47e include the X-axis coordinates.

[0042] As shown in Figure 4, the end effector control unit 55 controls the slide-type end effector 115. The end effector control unit 55 also controls the spindle unit 128 and the X-slider 129. The coordinate determination unit 59 determines the robot spatial coordinates 52 and stores them in the memory unit 143.

[0043] The correction unit 57 corrects the slide axis 71 based on the robot spatial coordinates 52 and the slide axis coordinates (not shown). The correction unit 57 transmits the slide correction amount of the slide axis 71 to the slide axis control unit 60 and the robot control unit 53. The slide axis control unit 60 corrects the command value of the slide axis 71 based on the slide correction amount.

[0044] According to the robotic machining center 100 of this embodiment, the operating conditions can be recorded even when a slide axis 71 and an X-slider 129 are included.

[0045] The present invention is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention. All technical matters included in the technical concept described in the claims are covered by the present invention. The embodiments described above are preferred examples, but those skilled in the art can realize various alternatives, modifications, variations, or improvements from the contents disclosed herein, and these are included in the technical scope described in the appended claims. [Explanation of symbols]

[0046] 10 Robotic machining centers 13 Robots 13a Arm (Robot Arm) 15 End Effectors 21 End Effector Markers 24 Spindle 25 Main shaft motor 27 Tools 39. Camera (External position measuring device)

Claims

1. A robotic machining center that processes workpieces, A robotic arm and An end effector positioned at the tip of the robot arm, A spindle to which tools can be attached, The spindle motor rotates the aforementioned spindle, An end effector having, The end effector marker placed on the end effector, An external position measuring device is positioned at a distance from the robot arm and measures the position of the end effector marker. A robotic machining center.

2. A control device, When the workpiece is being machined, the spatial coordinates of the end effector marker measured by the external position measuring instrument, The load on the aforementioned spindle motor and The control device further includes a device for recording data over time. The robotic processing machine according to claim 1.

3. The robot arm is a multi-joint robot arm, A joint motor that rotates each joint, A tachometer that detects the rotation angle of each joint, It has, The control device records the load on the joint motor and the rotation angle detected by the tachometer over time. The robotic machining machine according to claim 2.

4. The end effector has a feed motor that moves the spindle along the Z-axis from which the spindle extends, The control device records the coordinates of the main spindle in the Z-axis and the load of the main spindle motor over time. A robotic machining center according to any one of claims 1 to 3.

5. The aforementioned workpiece has a work marker, The external position measuring instrument measures the coordinates of the work marker, The control device stores the coordinates of the work marker measured by the external position measuring instrument. A robotic processing machine according to any one of claims 1 to 4.

6. The spindle, to which the tool is mounted, rotates, and the end effector positioned at the tip of the robot arm processes the workpiece. An external position measuring instrument measures the end effector spatial coordinates of the end effector marker of the end effector during machining. The position of the end effector is determined. Processing method.

7. The control device records the load on the spindle and the spatial coordinates over time. The processing method according to claim 6.

8. Furthermore, The external position measuring instrument measures the work space coordinates of the work marker of the workpiece during machining. The position of the workpiece is determined. The processing method according to claim 6 or 7.

9. Furthermore, Based on the end effector spatial coordinates and the workpiece spatial coordinates, the position of the robot arm or the position of the main spindle is corrected. The processing method according to claim 8.

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