Robot control device

Abstract

This robot control device is provided with: a temperature detection unit that detects a measured temperature of a robot; and a force control unit that performs force control of the robot. The robot control device is provided with: a change amount detection unit that detects a change amount of a position of the robot; and a calculation unit that calculates a length of a predetermined measurement portion. The change amount detection unit detects the change amount from a first position, which is an initial position of the robot, to a second position of the robot after the robot is driven by the force control. The calculation unit calculates the length of the measurement portion on the basis of a correlation between the change amount and the length of the measurement portion with respect to the measured temperature, the measured temperature, and the change amount.

Description

Robot control device

[0001] The present disclosure relates to a robot control device.

[0002] In the prior art, a device equipped with a contact probe is known as a device for measuring the dimensions of a workpiece. The machine's control device moves the contact probe with the machine and detects the position of the contact probe when the contact probe comes into contact with the workpiece. The control device can calculate the dimensions of the workpiece based on the position of the contact probe. For example, the machine brings the contact probe into contact with the surface of both sides of the workpiece in the thickness direction. The control device can calculate the thickness of the workpiece based on the difference in the positions of the contact probe at this time.

[0003] A robotic device includes a robot for moving a work tool and a robot control device for controlling the robot. It is known that a force sensor is attached to the robot so that the robot control device can precisely control the position and posture of the robot. The force sensor detects the force acting when a member supported by the robot comes into contact with another member. The robot control device can precisely adjust the position and posture of the robot based on the output of the force sensor. For example, by employing a force sensor, the robotic device can accurately measure the dimensions of a workpiece.

[0004] JP-A-3-158701 Publication of Special Publication No. 2016-524136 JP-A-5-80648 JP-A 3-140801

[0005] The robot control device can move a measuring device such as a contact probe with the robot, and can measure the dimensions of the workpiece based on the position and orientation of the robot when the robot places the measuring device at a predetermined position relative to the workpiece.

[0006] However, the position and posture of a robot depend on its temperature. For example, when the robot is driven, the temperature of the robot rises, which can cause thermal expansion of components such as the arm that make up the robot. As a result, even if an operation command is issued to move the tool tip to the coordinate values ​​of a predetermined teaching point, the actual position of the tool tip may change depending on the temperature of the robot.

[0007] As described above, there is a problem in that the length of the measurement portion of the workpiece calculated based on the position and posture of the robot changes depending on the temperature of the robot. Furthermore, when the temperature of the workpiece changes, the external shape of the workpiece changes due to thermal expansion or thermal contraction. In this case, there is also a problem in that the length of the measurement portion of the workpiece detected by the robot control device changes.

[0008] A robot control device according to a first aspect of the present disclosure includes a temperature detection unit that detects at least one of a measured temperature of the robot and a measured temperature of the workpiece, a force control unit that performs force control of the robot, and a state detection unit that detects the position and posture of the robot. The robot control device also includes a change amount detection unit that detects a change amount in the position of the robot, and a calculation unit that calculates a length of a predetermined measurement portion. The state detection unit detects a first position that is the initial position of the robot and a second position of the robot after driving the robot by force control. The change amount detection unit detects the change amount from the first position to the second position. A correlation between the change amount and the length of the measurement portion relative to the measured temperature is predetermined. The calculation unit calculates the length of the measurement portion based on the measured temperature, the change amount, and the correlation.

[0009] A robot control device according to a second aspect of the present disclosure includes a temperature detection unit that detects at least one of a measured temperature of the robot and a measured temperature of a workpiece, a force control unit that performs force control of the robot, and a state detection unit that detects the position and posture of the robot. The robot control device also includes a change amount detection unit that detects a change amount in the posture of the robot, and a calculation unit that calculates an angle relative to a predetermined measurement plane. The state detection unit detects a first posture that is the initial posture of the robot and a second posture of the robot after the robot is driven by force control. The change amount detection unit detects the change amount from the first posture to the second posture. A correlation between the change amount and the angle relative to the measurement plane with respect to the measured temperature is predetermined. The calculation unit calculates the angle relative to the measurement plane based on the measured temperature, the change amount, and the correlation.

[0010] 1 is a schematic diagram of a robot device according to a first embodiment; 2 is a block diagram of the robot device according to the first embodiment; 3 is an enlarged perspective view of a gauge and a workpiece; 4 is a side view of the robot, gauge, and workpiece when the temperature of the robot changes; 5 is a side view of the robot, gauge, and workpiece when the temperature of the workpiece changes; 6 is an enlarged side view of a robot device according to a third embodiment; 7 is a perspective view of a workpiece and an abutting member; 8 is a side view of the robot, workpiece, and abutting member; 9 is a side view of the robot, workpiece, and abutting member according to a fourth embodiment; 10 is an enlarged partial cross-sectional view of a robot device according to a fifth embodiment; 11 is a partial cross-sectional view of the robot, pressing member, and workpiece; 12 is an enlarged side view of a robot device according to a sixth embodiment; 13 is a block diagram of the robot device according to the sixth embodiment; 14 is a side view of the robot, polishing tool, and workpiece.

[0011] 1 to 5, a robot control device and a robot device including the robot control device according to a first embodiment will be described. The robot device in this embodiment measures the dimensions of a predetermined measurement portion of a workpiece.

[0012] 1 is a schematic diagram of a robot device according to the present embodiment. The robot device 5 includes a hand 2 as a work tool and a robot 1 that moves the hand 2. The robot 1 according to the present embodiment is an articulated robot that includes multiple joints 18. The robot 1 includes multiple movable components. The components of the robot 1 are configured to rotate around their respective drive axes.

[0013] The robot 1 of this embodiment includes a base 14 and a swivel base 13 that rotates relative to the base 14. The robot 1 also includes an upper arm 11 and a lower arm 12. The lower arm 12 is rotatably supported by the swivel base 13. The upper arm 11 is rotatably supported by the lower arm 12. The robot 1 also includes a wrist 15 that is rotatably supported by the upper arm 11. A hand 2 is fixed to a flange 16 of the wrist 15. Furthermore, the upper arm 11 or the flange 16 rotates around a predetermined drive axis.

[0014] The robot in this embodiment has six drive axes, but is not limited to this configuration. A robot whose position and posture can be changed by any mechanism can be used. Furthermore, the work tool in this embodiment is a hand with two claws, but is not limited to this configuration. Any device can be used as the work tool depending on the work to be performed by the robot device.

[0015] A reference coordinate system 9 is set in the robot device 5 of this embodiment. The reference coordinate system 9 is also called a world coordinate system. The reference coordinate system 9 is a coordinate system in which the position of the origin is fixed and the orientation of the coordinate axes is also fixed.

[0016] In addition, a tool coordinate system 92 having its origin at an arbitrary position on the work tool is set in the robot device 5. In this embodiment, the origin of the tool coordinate system 92 is set at the tool tip point, which is the midpoint between the tips of the two claws of the hand 2. The tool coordinate system 92 is a coordinate system whose position and orientation change along with the work tool. The position of the robot 1 corresponds to the position of the origin of the tool coordinate system 92 in the reference coordinate system 91. Furthermore, the orientation of the robot 1 corresponds to the orientation of the tool coordinate system 92 with respect to the reference coordinate system 91.

[0017] A block diagram of a robot device according to this embodiment is shown in Figure 2. Referring to Figures 1 and 2, robot 1 includes a robot drive device that changes the position and posture of robot 1. The robot drive device includes robot drive motors 22 that drive components such as the arm and wrist. In this embodiment, a plurality of robot drive motors 22 are arranged corresponding to the respective drive axes.

[0018] The robot device 5 includes a tool driving device that drives the hand 2. The tool driving device includes a hand driving motor 21 that drives the claws of the hand 2. The claws of the hand 2 open and close when driven by the hand driving motor 21. The hand may be configured to be driven by air pressure or the like.

[0019] The robot device 5 includes a control device 4 as a robot control device that controls the robot 1 and the hand 2. The control device 4 includes a control device main body 40 and a teaching operation panel 37 that allows an operator to operate the control device main body 40. The control device main body 40 includes an arithmetic processing device (computer) having a CPU (Central Processing Unit) as a processor. The arithmetic processing device has a RAM (Random Access Memory), a ROM (Read Only Memory), etc. that are connected to the CPU via a bus.

[0020] The teaching pendant 37 is connected to the control device main body 40 via a communication device. The teaching pendant 37 includes an input unit 38 for inputting information about the robot 1 and the hand 2. The input unit 38 is composed of input members such as a keyboard and a dial. The teaching pendant 37 includes a display unit 39 for displaying information about the robot 1 and the hand 2. The display unit 39 can be composed of any display panel, such as a liquid crystal display panel or an organic EL (Electro Luminescence) display panel. Note that when the teaching pendant is equipped with a touch panel type display panel, the display panel functions as both the input unit and the display unit.

[0021] An operation program 46 created in advance for operating the robot 1 and the hand 2 is input to the control device 4. Alternatively, an operator can set teaching points for the robot 1 by operating the teaching operation panel 37 to drive the robot 1. The control device 4 can generate the operation program 46 based on the teaching points.

[0022] The control device main body 40 includes a motion control unit 43 that controls the motion of the robot 1 and the hand 2. The motion control unit 43 sends motion commands for driving the robot 1 to the robot driving unit 45. The robot driving unit 45 includes an electrical circuit that drives the robot driving motor 22. The robot driving unit 45 supplies electricity to the robot driving motor 22 based on the motion commands. The motion control unit 43 also sends motion commands for driving the hand 2 to the tool driving unit 44. The tool driving unit 44 includes an electrical circuit that drives the hand driving motor 21. The tool driving unit 44 supplies electricity to the hand driving motor 21 based on the motion commands.

[0023] The control device main body 40 includes a storage unit 42 that stores information related to the control of the robot 1 and the hand 2. The storage unit 42 can be configured with a non-transitory storage medium capable of storing information. For example, the storage unit 42 can be configured with a storage medium such as a volatile memory, a non-volatile memory, a magnetic storage medium, or an optical storage medium. An operation program 46 is stored in the storage unit 42.

[0024] The operation control unit 43 corresponds to a processor that operates in accordance with the operation program 46. The processor is configured to be able to read information stored in the storage unit 42. The processor reads the operation program 46 and controls the robot 1 and the hand 2 as defined in the operation program 46, thereby functioning as the operation control unit 43.

[0025] The robot 1 includes a state detector for detecting the position and posture of the robot 1. The state detector in this embodiment includes a position detector 19 attached to the robot drive motor 22 of each drive shaft to detect the rotational position. The position detector 19 can be configured with an encoder that detects the rotation angle of the output shaft of the robot drive motor 22. In this embodiment, the position and posture of the robot 1 are detected based on the outputs of the multiple position detectors 19.

[0026] The control device 4 includes a force sensor 24 as a force detector attached to the robot 1. The force sensor 24 in this embodiment is a six-axis sensor. In the robot device 5 of this embodiment, the force sensor 24 is disposed between the flange 16 and the hand 2. The force sensor 24 detects forces and moments acting on a member grasped by the hand 2. Any force sensor, such as a sensor including a strain sensor or a capacitance sensor, can be used as the force sensor 24.

[0027] In this embodiment, the forces detected by the force sensor include linearly acting forces and moments acting as forces that rotate the shaft. A sensor coordinate system is set in the force sensor 24 for detecting forces acting on the sensor. The forces detected by the force sensor 24 include forces acting in the directions of three mutually orthogonal axes in the sensor coordinate system and forces acting around the three axes. More specifically, the force sensor 24 detects forces acting in the directions of three orthogonal axes (X-axis, Y-axis, and Z-axis) and moments acting as forces acting in the directions of axes (W-axis, P-axis, and R-axis) around the three axes.

[0028] The robot 1 of this embodiment is equipped with a temperature sensor 25 for measuring the temperature of the robot 1. A representative temperature of the robot 1 can be used as the measured temperature of the robot 1. For example, the temperature of the air around the robot, the temperature of one of the robot's components such as the housing of the base, or the temperature of the housing of the work tool can be used. Alternatively, the measured temperature of the robot 1 can be an average value of the temperatures of multiple components of the robot 1. For example, the measured temperature of the robot can be detected by attaching a temperature sensor to the housing of each joint of the robot and averaging multiple temperatures. Furthermore, the temperature of the work tool may be included in the multiple temperatures used to calculate the average value.

[0029] The control device 4 in this embodiment can measure the dimensions of a member supported by a robot or a member fixed by a fixing member. In this example, the control device 4 measures the diameter of a hole 75a in a workpiece 75 fixed to a fixing member 71.

[0030] The control device main body 40 includes a measurement control unit 51 that controls the measurement of the length of a predetermined measurement portion. The measurement control unit 51 includes a state detection unit 52 that detects the position and posture of the robot. The state detection unit 52 detects the position and posture of the robot based on the output of a position detector 19 attached to the robot drive motor 22.

[0031] The measurement control unit 51 includes a temperature detection unit 53 that detects at least one of the measured temperatures of the robot and the workpiece. The temperature detection unit 53 detects the temperature of the robot or the workpiece based on the output of a temperature sensor disposed in at least one of the robot 1, the hand 2, and the environment surrounding the robot device 5. In this example, the temperature detection unit 53 detects the temperature of the robot 1 based on the output of the temperature sensor 25.

[0032] The measurement control unit 51 includes a change amount detection unit 54 that calculates the amount of change in the position of the robot. The state detection unit 52 detects a first position, which is the initial position of the robot, and a second position of the robot after the robot is driven by force control. The change amount detection unit 54 detects the amount of change in the position of the robot from the first position to the second position.

[0033] The measurement control unit 51 includes a calculation unit 55 that calculates the length of a predetermined measurement portion. The calculation unit 55 in this embodiment calculates the dimension of the predetermined portion of the workpiece.

[0034] The measurement control unit 51, the state detection unit 52, the temperature detection unit 53, the change amount detection unit 54, and the calculation unit 55 correspond to a processor that operates in accordance with the operation program 46. The processor reads the operation program 46 and performs the control defined in the operation program 46, thereby functioning as each unit.

[0035] The measurement control unit 51 also includes a force control unit 56 that performs force control of the robot. In this embodiment, the term "force control" refers to control that adjusts the position and posture of the robot based on the force detected by the force detector. Force control utilizes the force that occurs when a member supported by the robot comes into contact with a member fixed to a fixed member. Force control can also control the movement of the robot based on the magnitude and direction of a force acting on a predetermined point of application. For example, the force control unit 56 can perform compliance control or impedance control based on the force detected by the force sensor 24.

[0036] The measurement control unit 51 includes a motion command generation unit 57 that generates a motion command for the robot based on the motion of the robot determined by the force control unit 56. The motion control unit 43 controls the robot 1 and the hand 2 based on the motion command generated by the motion command generation unit 57.

[0037] The force control unit 56 and the motion command generation unit 57 correspond to a processor that operates in accordance with the motion program 46. The processor reads the motion program 46 and performs the control defined in the motion program, thereby functioning as each unit.

[0038] Fig. 3 shows an enlarged perspective view of the gauge and workpiece in this embodiment. Referring to Figs. 1 and 3, workpiece 75 in this embodiment is formed in a disk shape. A hole 75a having a circular planar shape is formed in the center of workpiece 75. Workpiece 75 is fixed to a stand 89 by a fixing member 71. A hole 71a is formed in fixing member 71 so as to correspond to hole 75a in workpiece 75.

[0039] The robot device 5 includes a gauge 81 as a measuring device for measuring the diameter of a hole 75a in the workpiece 75. A gripping portion 81a of the gauge 81 is gripped by being pinched by the claws of the hand 2.

[0040] The gauge 81 has a measuring unit 81b that has the function of measuring dimensions by contacting the workpiece 75. The measuring unit 81b is formed in a truncated cone shape. The measuring unit 81b is inserted into the hole 75a of the workpiece 75, as shown by arrow 95. The diameter of the hole 75a can be measured based on the position at which the measuring unit 81b comes into contact with the hole 75a and stops. In other words, the diameter of the hole 75a can be measured based on the depth to which the measuring unit 81b is inserted into the workpiece 75.

[0041] 4 shows a side view of the robot, the gauge, and the workpiece when measuring the diameter of the hole in the workpiece according to this embodiment, in which the robot is at a first position P1, which is the initial position when starting measurement, and the robot is at a second position P2, which is the end position when calculating the diameter of hole 75a.

[0042] The force control unit 56 of the control device 4 moves the gauge 81 so that the axial direction of the measuring unit 81b of the gauge 81 substantially coincides with the axial direction of the hole 75a in the workpiece 75. As shown by arrow 95, the measuring unit 81b is inserted into the hole 75a. In this example, the gauge 81 is moved in the direction of the Z axis of the tool coordinate system 92.

[0043] When inserting measuring unit 81b into hole 75a, force control unit 56 performs force control based on the output of force sensor 24. Force control unit 56 calculates the force and moment in a predetermined direction at the point of application based on the output of force sensor 24. Force control unit 56 controls the position and posture of the robot so that the force and moment in the predetermined direction at the point of application reach their respective target values.

[0044] In this example, the position and orientation of the gauge 81 can be controlled so that a uniform force is applied radially to the outer peripheral surface of the measuring unit 81b. The force control unit 56 can control the robot 1, for example, so that at the tool tip point serving as the point of application, a reaction force is applied only in the negative direction of the Z axis of the tool coordinate system 92, and the forces and moments in other directions approach zero. Force control makes it possible to position the measuring unit 81b in an accurate position and orientation relative to the hole 75a. Here, the position and orientation of the gauge 81 can be adjusted so that the axis of the measuring unit 81b coincides with the axis of the hole 75a.

[0045] The first position P1 is the position of the robot when the gauge 81 is separated from the workpiece 75. The state detection unit 52 detects the first position P1 using coordinate values ​​in the reference coordinate system 91. The force control unit 56 moves the gauge 81 relative to the hole 75a, as shown by arrow 95. The measurement unit 81b of the gauge 81 comes into contact with the hole 75a in the workpiece 75. The force control unit 56 calculates the movement direction and movement amount of the robot so that the force and moment detected by the force sensor 24 approach target values. The movement command generation unit 57 generates a movement command for the robot 1 based on the calculation result of the force control unit 56. The movement control unit 43 controls the robot 1 based on the movement command generated by the movement command generation unit 57.

[0046] The second position P2 is the position of the robot when force control is completed. The state detection unit 52 detects the second position P2 when the gauge 81 is placed at the desired position by force control, using coordinate values ​​in the reference coordinate system 91. The change amount detection unit 54 detects the amount of change Hx in the robot's position from the first position P1 to the second position P2. The amount of change Hx in the robot's position can be calculated from the coordinate values ​​in the reference coordinate system of the first position P1 and the second position P2. In this embodiment, the amount of change Hx in the robot's position corresponds to the insertion depth to which the gauge 81 is inserted into the workpiece 75. The calculation unit 55 can calculate the diameter of the hole 75a based on the amount of change Hx in the position.

[0047] Here, when the temperature of the robot 1 changes, the actual position and posture of the robot change relative to the command values ​​for the position and posture of the robot. For example, when the temperature of the robot 1 rises and the length of an arm such as the upper arm 11 or the lower arm 12 changes, the coordinate value of the position of the tool tip point in the reference coordinate system 91 changes. Referring to FIG. 4 , if the temperature of the workpiece 75 does not change but the temperature of the robot 1 changes, the second position P2 does not change but the first position P1 changes. Therefore, when the temperature of the robot 1 changes, the calculated amount of change Hx in the position changes. Here, the measurement control unit 51 calculates the dimensions of the hole 75a in the workpiece 75 based on the temperature of the robot 1.

[0048] In this embodiment, the correlation between the length of the measurement portion and the amount of change in the robot position and the measured temperature of the robot is determined in advance. In this example, the diameter of the hole 75a corresponds to the length of the measurement portion. In this embodiment, the correlation is determined based on previously measured reference data.

[0049] Table 1 shows reference data that indicates the correlation between the diameter of hole 75a and the temperature of robot 1 and the amount of change in robot position. Reference data 47 in this embodiment is created in advance and stored in storage unit 42. The reference data includes a set of a reference temperature related to the measured temperature, a reference amount of change in position, and a reference length related to the length of the measured portion. The reference data includes multiple sets.

[0050]

[0051] In this example, the temperatures of the robot are indicated by reference temperatures Ta and Tb. Reference workpieces are generated so that the positional change amounts as insertion depths are reference change amounts H1, H2, and H3 at the respective reference temperatures Ta and Tb. Furthermore, the reference lengths D1a, D2a, and D3a, which are the diameters of the holes in the respective reference workpieces, are accurately measured by a measuring device such as a micrometer or laser sensor.

[0052] For example, a reference workpiece is created so that the amount of position change is a reference change amount H1 when the robot temperature is at a reference temperature Ta. Then, the diameter of the hole in the reference workpiece is measured as a reference length D1a. A similar reference workpiece is created and the diameter of the hole is measured at a reference temperature Tb. At this time, a reference workpiece having reference changes H1, H2, and H3 is also created at the reference temperature Tb. In this way, the reference data has multiple pairs of a reference temperature, a reference change amount of position, and a reference length.

[0053] The reference data in Table 1 is composed of two temperatures, but is not limited to this and may be composed of three or more temperatures. Also, any number of reference variations and reference lengths can be generated.

[0054] In measuring the length of the actual measurement portion, the calculation unit 55 of the measurement control unit 51 can calculate the diameter of the hole 75a based on the correlation between the measured temperature of the robot, the amount of change in position, and the reference data. The calculation unit 55 of this embodiment can calculate the diameter of the hole 75a by interpolating or extrapolating the amount of change in position and the measured temperature of the robot 1.

[0055] More specifically, the temperature detection unit 53 detects the measured temperature Trx (e.g., Ta≦Trx<Tb) of the robot 1 based on the output of the temperature sensor 25. The change amount detection unit 54 detects the change amount Hx (e.g., H1≦Hx<H2) in the position of the robot. The calculation unit 55 can calculate the diameter Dx of the hole 75a in the workpiece 75 using the following equation (1).

[0056] Dx=Dax+Ct(Dbx-Dax)...(1)

[0057] Here, the variables Dax, Dbx, and Ct in equation (1) can be calculated using the following equations (2) to (5).

[0058] Dax=D1a+Ch(D2a-D1a)...(2) Dbx=D1b+Ch(D2b-D1b)...(3) Ct=(Trx-Ta) / (Tb-Ta)...(4) Ch=(Hx-H1) / (H2-H1)...(5)

[0059] Equation (1) represents interpolation based on the temperature of the robot. Equations (2) and (3) represent interpolation based on the amount of change in position. In this manner, in this embodiment, the length of the measurement portion is calculated by interpolating the amount of change in position and the temperature, but this is not limiting. The length of the measurement portion may also be calculated by extrapolating at least one of the amount of change in position and the measured temperature.

[0060] In this embodiment, the correlation between the length of the predetermined measurement portion and the amount of change in position and the measured temperature is determined in a table, but this is not limiting. For example, the length of the measurement portion may be calculated using a polynomial that uses the amount of change in position and the measured temperature as variables.

[0061] Here, even if the temperature of the workpiece changes and the outer shape of the workpiece changes, the dimensions of the measurement portion can be calculated using control similar to the above control. Next, a control for calculating the length of the measurement portion based on the temperature of the workpiece will be described.

[0062] Figure 5 shows a side view of the robot, gauge, and workpiece when the temperature of the workpiece changes. Figure 5 shows the first position P1, which is the initial position of the robot, and the second position P2, which is the end position after force control is performed. This shows an example where the temperature of the workpiece 75 rises without changing the temperature of the robot 1. The temperature of the workpiece 75 rises, and it becomes thicker than the workpiece 75 shown in Figure 4.

[0063] The temperature sensor 25 is arranged to directly measure the temperature of the workpiece 75. Alternatively, the temperature sensor 25 may be arranged to measure the temperature of the air around the workpiece 75 as the temperature of the workpiece 75. The temperature detection unit 53 detects the temperature of the workpiece 75 based on the output of the temperature sensor 25.

[0064] The first position P1 of the robot is constant and does not depend on the temperature of the workpiece 75. In contrast, when the temperature of the workpiece 75 changes, the second position P2 of the robot changes in accordance with the temperature of the workpiece 75. The state detection unit 52 detects the first position P1 and the second position P2 of the robot.

[0065] The change amount detection unit 54 detects the amount of change in the position of the robot from the first position P1 to the second position P2. When the temperature of the workpiece 75 rises and the workpiece 75 becomes thicker, the insertion depth of the measuring portion 81b of the gauge 81 into the hole 75a decreases.

[0066] Before performing the actual measurement, the operator can create reference data by applying the reference temperature of the workpiece instead of the reference temperature of the robot in Table 1. Then, similar to the case where the temperature of the robot changes, the calculation unit 55 can calculate the diameter of the hole 75a in the workpiece 75 based on the amount of change in the position of the robot, the measured temperature of the workpiece, and the correlation indicated in the reference data.

[0067] In the robot control device of this embodiment, by performing force control, it is possible to accurately position a member supported by the robot relative to a member fixed to a fixed member. At this time, errors occur in the position of the robot during measurement due to the influence of the temperature of the robot or the temperature of the workpiece. However, in this embodiment, the length of the measurement portion is calculated based on the correlation between the measured temperature, the amount of change in position, and the length of the measurement portion, so the length of the measurement portion can be calculated with high accuracy.

[0068] In this embodiment, a gauge is used as a measuring instrument for measuring dimensions, but this is not limited to this. Any measuring instrument capable of measuring the length of a measurement part can be used. Furthermore, in this embodiment, the dimension of the workpiece is the diameter of the hole, but this is not limited to this, and the dimension of any part of the workpiece can be measured.

[0069] In this embodiment, the gauge serving as the measuring device is supported by the robot, and the workpiece is fixed to a stationary member, but this is not limiting. The workpiece may be supported by the robot, and the measuring device may be fixed to a stationary member. The dimensions of the workpiece supported by the robot may then be measured.

[0070] In this embodiment, a six-axis force sensor is disposed in the wrist as a force detector, but this is not a limitation. Any sensor capable of detecting forces and moments acting on a point of application can be used as the force detector. For example, a torque sensor may be disposed in the joint of the robot. Multiple torque sensors are disposed on the drive shafts of multiple joints of the robot. Each torque sensor can detect torque around the drive shaft of the joint. The force control unit can detect the forces and moments acting on the point of application based on the output of the torque sensors.

[0071] Second Embodiment A robot control device and a robot device according to a second embodiment will be described with reference to Figures 1 to 5. The robot control device according to this embodiment calculates the length of the measurement portion based on both the measured temperature of the robot and the measured temperature of the workpiece. In this embodiment, similar to the first embodiment, the diameter of a hole 75a in a workpiece 75 is measured.

[0072] The robot device is equipped with multiple temperature sensors. A first temperature sensor is arranged to measure the temperature of the robot. A second temperature sensor is arranged to measure the temperature of the workpiece. A temperature detection unit 53 detects the measured temperatures of the robot 1 and the workpiece. The rest of the configuration of the robot device is the same as that of the robot device 5 in the first embodiment (see FIGS. 1 and 2).

[0073] The state detection unit 52 detects the position and posture of the robot at the first position P1 and the second position P2. The change amount detection unit 54 detects the amount of change Hx in the position.

[0074] The worker can predetermine a reference temperature T0 for the workpiece. For example, the reference temperature T0 can be set to a temperature close to room temperature. Table 2 shows reference data indicating the relationship between the reference length corresponding to the diameter of the hole 71a and the amount of position change relative to the reference temperature of the robot when the workpiece temperature is the reference temperature T0. For example, the worker creates a reference workpiece whose hole diameter is a reference length D1 when the workpiece temperature is the reference temperature T0. Then, the worker actually measures the reference position changes H1a, H2a, and H3a when the robot is changed to reference temperatures Tr1, Tr2, and Tr3, thereby creating the reference data. Similarly, the worker creates a reference workpiece having a reference length D2 when the workpiece is at the reference temperature T0, and actually measures the reference position changes H1b, H2b, and H3b.

[0075]

[0076] Furthermore, Table 3 shows reference data indicating the relationship between the reference length corresponding to the diameter of the hole 71a when the workpiece temperature is at the reference temperature T0 and the reference length when the workpiece temperature is at the reference temperature. For example, an operator creates a reference workpiece whose hole diameter is the reference length D01 when the workpiece temperature is at the reference temperature T0. Then, the reference data is created by actually measuring the reference lengths D1a, D2a, and D3a when the workpiece is changed to the reference temperatures Tw1, Tr2, and Tw3. Similarly, a reference workpiece having the reference length D02 when the workpiece is at the reference temperature T0 is created, and the reference lengths D1b, D2b, and D3b are actually measured.

[0077]

[0078] In actual measurements, the measurement control unit 51 detects the measured temperature of the robot, the measured temperature of the workpiece, and the amount of change in position. For example, when the temperature of the robot is measured temperature T (Tr1≦Trx<Tr2), the temperature of the workpiece is measured temperature Twx (Tw1≦Twx<Tw2), and the amount of change in the position of the robot is change amount Hx, the following equations (6) to (11) hold.

[0079] (Hxa-H1a) / (H2a-H1a)=(Trx-Tr1) / (Tr2-Tr1)…(6) (Hxb-H1b) / (H2b-H1b)=(Trx-Tr1) / (Tr2-Tr1)…(7) (Dx-D1) / (D2-D1)=(Hx-Hxa) / (Hxb-Hxa)…(8) (Dax-D1a) / (D2a-D1a)=(Twx-Tw1) / (Tw2-Tw1) …(9) (Dbx-D1b) / (D2b-D1b)=(Twx-Tw1) / (Tw2-Tw1) …(10) (D0x-D01) / (D02-D01)=(Dx-Dax) / (Dbx-Dax)…(11)

[0080] The calculation unit 55 can calculate the diameter D0x of the hole in the workpiece at the reference temperature T0 by interpolating or extrapolating the amount of change in the robot position, the measured temperature of the robot, and the measured temperature of the workpiece. The length D0x at the reference temperature T0 can be calculated from the following equation (12).

[0081] D0x=D01+C0(D02-D01)…(12)

[0082] Here, the variable C0 is calculated based on the following equations (13) to (21).

[0083] C0=(Dx-Dax) / (Dbx-Dax)...(13) Dx=D1+C1(D2-D1)...(14) C1=(Hx-Hxa) / (Hxb-Hxa)...(15) Hxa=H1a+C2(H2a-H1a)...(16) Hxb=H1b+C2(H2b-H1b)...(17) C2=(Trx-Tr1) / (Tr2-Tr1)...(18) Dax=D1a+C3(D2a-D1a)...(19) Dbx=D1b+C3(D2b-D1b)...(20) C3=(Twx-Tw1) / (Tw2-Tw1)...(21)

[0084] In this way, even when the temperature of the robot and the temperature of the workpiece change simultaneously, the operator can create reference data that indicates the correlation between the amount of change in position and the length of the measured portion relative to the measured temperature, and the measurement control unit can then accurately calculate the length of the measured portion even when the measured temperature of the robot and the measured temperature of the workpiece change simultaneously.

[0085] Other configurations, operations, and effects of the robot control device and robot device are similar to those of the robot control device and robot device of the first embodiment, and therefore will not be described repeatedly here.

[0086] 6 to 8, a robot control device and a robot device according to a third embodiment will be described. The robot control device according to this embodiment measures the machining length of a member supported by the robot or a member fixed to a stationary member. In other words, it measures the length of the machined portion of the workpiece in a predetermined direction.

[0087] FIG. 6 shows a schematic side view of the robot device according to this embodiment. FIG. 7 shows an enlarged perspective view of the workpiece and the contact member. With reference to FIGS. 2, 6, and 7, in the robot device 7 according to this embodiment, the hand 2 attached to the robot 1 grips the workpiece 76. The workpiece 76 corresponds to a member supported by the robot 1. The workpiece 76 according to this embodiment has a cylindrical shape. A bottom surface 76a of the workpiece 76 is cut by a separate cutting device. For example, the robot device 7 cuts the bottom surface 76a of the workpiece 76 by bringing the bottom surface 76a into contact with a polishing device or a grinder. The bottom surface 76a corresponds to the machined surface.

[0088] The robot device 7 of this embodiment includes a contact member 83 against which the bottom surface 76a of the workpiece 76 comes into contact. The surface 83a of the contact member 83 is formed in a flat shape. The contact member 83 corresponds to a member fixed to the fixed member 72. The fixed member 72 is fixed to a stand 89.

[0089] The measurement control unit 51 of the control device 4 calculates the machining length in the axial direction of the workpiece 76. The measurement control unit 51 brings the bottom surface 76a of the workpiece 76 into surface contact with the surface 83a of the contact member 83 before and after machining. Then, the machining length is calculated based on the amount of change in the position of the robot.

[0090] 8 shows a side view of the robot, the workpiece, and the contact member at a first position before machining the workpiece and at a second position after machining the workpiece. The first position P1 is the position of the robot when the workpiece 76 supported by the robot 1 comes into contact with the contact member 83 before machining the workpiece 76.

[0091] The robot 1 moves the workpiece 76 as shown by arrow 95 to bring it into contact with the abutment member 83. At this time, the force control unit 56 performs force control so that the bottom surface 76a of the workpiece 76 comes into surface contact with the surface 83a of the abutment member 83. For example, the position and posture of the robot are controlled so that the moment acting on the tool tip in a predetermined direction approaches zero. The state detection unit 52 detects a first position P1 of the robot.

[0092] Next, another device processes the bottom surface 76a of the workpiece 76 into a flat surface. The second position P2 is the position of the robot 1 when the workpiece 76 supported by the robot 1 comes into contact with the contact member 83 after the workpiece 76 has been processed. The force control unit 56 performs force control so that the bottom surface 76a of the workpiece 76 comes into surface contact with the surface 83a of the contact member 83. The state detection unit 52 detects the second position P2 of the robot.

[0093] The change amount detection unit 54 calculates the distance between the first position P1 and the second position P2 as the amount of change in position. The calculation unit 55 calculates the machining length in the axial direction of the workpiece 76 as the length of the measurement portion based on the amount of change in position. In other words, the calculation unit 55 calculates the machining length in the direction from the first position to the second position of the member supported by the robot.

[0094] In this embodiment, too, the machining length is calculated based on at least one of the measured temperatures of the robot and the workpiece. First, an example of calculating the machining length based on the measured temperature of the robot 1 will be described. As shown in Table 4, the worker can create reference data including a set of the reference change amount of the robot position, the reference temperature of the robot, and the reference length.

[0095]

[0096] As in the first embodiment, for example, when the temperature of the robot is at a reference temperature Ta, the respective reference workpieces can be generated so that the positional changes become reference changes H1, H2, and H3. Then, the machining lengths D1a, D2a, and D3a as reference lengths can be accurately measured using a measuring instrument or the like.

[0097] In measuring the actual machining length of a workpiece, when the temperature of the robot is a measurement temperature Trx (for example, Ta≦Trx<Tb) and the amount of change in position is Hx (for example, H1≦Hx<H2), the machining length Dx can be calculated by the following equation (22), as in the first embodiment.

[0098] Dx=Dax+Ct(Dbx-Dax)...(22)

[0099] Furthermore, the variables Dax, Dbx, and Ct included in equation (22) can be calculated using the following equations (23) to (26).

[0100] Dax=D1a+Ch(D2a-D1a)...(23) Dbx=D1b+Ch(D2b-D1b)...(24) Ct=(Trx-Ta) / (Tb-Ta)...(25) Ch=(Hx-H1) / (H2-H1)...(26)

[0101] Next, a case where the temperature of the workpiece changes will be described. When the temperature of the workpiece changes, reference data can be created by changing the reference temperature of the robot in Table 4 to the reference temperature of the workpiece. The temperature sensor 25 can be arranged to detect the temperature of the workpiece 76. The temperature detection unit 53 detects the temperature of the workpiece 75 based on the output of the temperature sensor 25. The measurement control unit 51 detects the measured temperature of the workpiece and can calculate the machining length Dx in the same way as the calculation method of equations (22) to (26).

[0102] In the control of this embodiment, the workpiece is held by the hand and the contact member is fixed to the stationary member, but this is not limiting. Similar control can be performed when the workpiece is fixed to the stationary member and the contact member is held by the hand and moved. The surface of the workpiece fixed to the stationary member can be machined, for example, by another robot device.

[0103] Other configurations, operations, and effects of the robot control device and robot device are similar to those of the robot control device and robot device of the first and second embodiments, and therefore will not be described repeatedly here.

[0104] (Fourth embodiment) A robot control device and a robot device according to a fourth embodiment will be described with reference to FIG. 9 . The robot control device according to this embodiment calculates an angle related to a predetermined measurement surface. In particular, the robot control device according to this embodiment measures a machining angle, which is a machined angle of a member supported by the robot or a member fixed to a fixed member. The measurement surface is the surface of the workpiece to be machined. The robot control device measures the angle between the pre-machining surface and the post-machining surface when viewed from a predetermined direction. The configuration of the robot device according to this embodiment is similar to the configuration of the robot device 7 according to the third embodiment.

[0105] 9 shows side views of the robot, workpiece, and contact member in the first and second positions. With reference to FIGS. 2 and 9, an example of machining a workpiece 76 supported by the robot 1 will be described. The bottom surface 76a of the workpiece 76 before machining is flat. The robot device 7 of this embodiment cuts the bottom surface 76a into a flat shape. At this time, machining is performed so that the angle of the bottom surface 76a before machining relative to an axis 79 of the workpiece 76 is different from the angle of the bottom surface 76a after machining relative to the axis 79. The bottom surface 76a before machining is perpendicular to the axis 79, but the bottom surface 76a after machining is inclined at an angle Sx relative to the axis 79.

[0106] The temperature detection unit 53 acquires at least one of the measured temperatures of the robot 1 and the workpiece 76. Here, an example will be described in which the temperature of the robot 1 changes. The temperature detection unit 53 detects the measured temperature of the robot 1.

[0107] The force control unit 56 performs force control so that the unmachined bottom surface 76a comes into surface contact with the surface 83a of the abutment member 83, thereby causing the robot posture to assume a first posture R1. The first posture R1 is the initial posture of the robot. The first posture R1 is the posture of the robot when the workpiece 76 supported by the robot 1 comes into surface contact with the abutment member 83 fixed to the fixed member 72 before machining. The state detection unit 52 detects the position and posture of the robot 1.

[0108] Next, the robot device 7 transports the workpiece 76 to another device and cuts the bottom surface 76 a. Next, the robot device 7 places the machined workpiece 76 above the contact member 83. The force control unit 56 performs force control so that the machined bottom surface 76 a comes into surface contact with the surface 83 a of the contact member 83.

[0109] By driving the robot using force control, the robot assumes a second posture R2. The second posture R2 is the final posture of the robot. The second posture R2 is the posture of the robot when, after machining, the workpiece 76 supported by the robot 1 comes into surface contact with the abutment member 83 fixed to the fixed member 72. The state detection unit 52 detects the position and posture of the robot 1.

[0110] The change amount detection unit 54 detects the amount of change in the robot's posture. The change amount detection unit 54 detects the amount of change in the posture of the robot 1 from the first posture R1 to the second posture R2. The amount of change in posture here corresponds to the amount of change in the angle of the bottom surface 76a with respect to the axial direction of the workpiece 76 when the bottom surface 76a is cut. The amount of change in the robot's posture can be calculated based on the posture R1 of the first robot and the posture R2 of the second robot.

[0111] The operator prepares in advance reference data that defines the correlation between the angle of the measurement surface relative to the amount of change in the robot's posture and the measured temperature of the robot. Table 5 shows the reference data 47 that indicates the correlation.

[0112]

[0113] The reference data here includes a plurality of sets of a reference change amount related to the amount of change in posture, a reference temperature related to the measured temperature, and a reference angle related to the processing angle. In this example, the angle related to the measurement surface is the processing angle when processing. The processing angle corresponds to the change amount of the posture of the robot when processing a member supported by the robot or a member fixed to a fixed member.

[0114] For example, similar to the first embodiment, reference workpieces are created so that the posture changes at the reference temperature Ta of the robot are reference changes S1, S2, and S3. Then, the reference angles B1a, B2a, and B3a of the reference workpieces are accurately measured using a measuring device such as a laser measuring device. Similar measurements are also performed at the reference temperature Tb of the robot.

[0115] In measuring the machining angle of an actual workpiece, the calculation unit 55 can calculate the angle related to the measurement surface by performing interpolation or extrapolation using the amount of change in posture and the measured temperature. In this example, when the measured temperature Trx (Ta≦Trx<Tb) of the robot and the actual amount of change in posture Sx (S1≦Sx<S2), the machining angle Bx can be calculated by the following equation (27).

[0116] Bx=Bax+Ct(Bbx-Bax)…(27)

[0117] Here, the variables Bax, Bbx, and Ct can be calculated using the following equations (28) to (31).

[0118] Bax=B1a+Ch(B2a-B1a)...(28) Bbx=B1b+Ch(B2b-B1b)...(29) Ct=(Trx-Ta) / (Tb-Ta)...(30) Ch=(Sx-S1) / (S2-S1)...(31)

[0119] By implementing the control of this embodiment, the machining angle can be measured with high accuracy. In the above embodiment, the machining angle is calculated based on the measured temperature of the robot, but this is not limiting. The machining angle may be calculated based on the measured temperature of the workpiece, as in the first to third embodiments.

[0120] Furthermore, in the above embodiment, the workpiece 76 to be machined is gripped by the robot 1, and the abutting member 83 is fixed by the fixing member 72, but this is not limited to this. The contact member may be supported by the robot, and the workpiece may be fixed to the fixing member. In this case, too, the amount of change in posture can be calculated based on a first posture when the contact member is brought into surface contact with the workpiece before machining, and a second posture when the contact member is brought into surface contact with the workpiece after machining. The operator can create reference data in advance. Then, the calculation unit can calculate the machining angle of the workpiece based on the measured temperature of the robot or the measured temperature of the workpiece, the amount of change in posture, and the reference data.

[0121] In the above embodiment, the processing angle is calculated, but the present invention is not limited to this. Any angle relative to a predetermined measurement surface can be measured. For example, the processing angle can be detected using a measuring device for detecting the processing angle.

[0122] Other configurations, operations, and effects of the robot control device and robot device are similar to those of the robot control device and robot device of the first to third embodiments, and therefore will not be described repeatedly here.

[0123] Fifth Embodiment A robot control device and a robot device according to a fifth embodiment will be described with reference to Figures 10 and 11. The robot control device of this embodiment measures the amount of movement of a slide member biased in a predetermined biasing direction as the length of a measurement portion.

[0124] 10 is an enlarged partial cross-sectional view of the robot device according to this embodiment. The workpiece 77 includes a slide member 77c and a spring 77b as a biasing member. The workpiece 77 in this embodiment is a push button switch, a keyboard key switch device, or the like. The slide member 77c is formed to be slidable along a recess formed in a base material 77a. The slide member 77c is biased by the spring 77b in a predetermined biasing direction, as indicated by arrow 96. The hand 2 holds a pressing member 84 for pressing the slide member 77c.

[0125] 11 shows partial cross-sectional views of the robot, pressing member, and workpiece when the robot is positioned at the first and second positions. Here, an example in which the temperature of the robot changes will be described. The first position P1 is a position where the pressing member 84 supported by the robot 1 contacts the slide member 77c. Alternatively, the first position may be a position where the pressing member 84 is separated from the slide member 77c.

[0126] 2 and 11, the force control unit 56 of the control device 4 controls the position and posture of the robot so as to move the pressing member 84 in the direction opposite to the biasing direction of the spring, as indicated by arrow 95. The force control unit 56 controls the robot so as to approach predetermined target values ​​for the force and moment. The pressing member 84 presses the slide member 77c.

[0127] The second position P2 is the position when the pressing member 84 stops pressing the slide member 77c. The second position P2 is also the position of the robot when the pressing member 84 presses the slide member 77c with a predetermined force in the direction opposite to the biasing direction. The force control unit 56 may press the slide member 77c to a position where it no longer moves. Alternatively, the force control unit 56 may press the slide member 77c to a position where the reaction force received from the spring 77b reaches a predetermined target value.

[0128] The temperature detection unit 53 detects the measured temperature of the robot 1. The state detection unit 52 detects the first position P1 and the second position P2. The change amount detection unit 54 detects the amount of change in the position of the robot. The worker creates reference data that indicates the correlation between the measured temperature and the amount of change in position and the movement length of the sliding member. The calculation unit 55 can then calculate the movement amount of the sliding member 77c based on the measured temperature, the amount of change in the robot's position, and the predetermined reference data.

[0129] When the temperature of the workpiece 77 changes, the operator creates reference data including the reference temperature of the workpiece 77. The measurement control unit 51 detects the measured temperature of the workpiece 77 and thereby calculates the amount of movement of the slide member.

[0130] The robot control device of this embodiment also detects at least one of the measured temperatures of the robot and the workpiece, and can accurately calculate the amount of movement of the slide member in the direction opposite to the force direction based on each measured temperature.

[0131] In the above embodiment, the pressing member 84 is supported by the robot 1, and the workpiece 77 including the slide member 77c is fixed to the fixed member 72, but this is not limiting. The workpiece including the slide member may be supported by the robot, and the pressing member may be fixed to a fixing device.

[0132] Other configurations, operations, and effects of the robot control device and robot device are similar to those of the robot control device and robot device of the first to fifth embodiments, and therefore will not be described repeatedly here.

[0133] 12 to 14, a robot control device and a robot device according to a sixth embodiment will be described. The robot device according to this embodiment polishes the surface of a workpiece with a polishing tool. The robot control device then calculates the machining length in a direction perpendicular to the surface of the workpiece as the length of a predetermined measurement portion.

[0134] An enlarged side view of the robot device according to the present embodiment is shown in Fig. 12. A block diagram of the robot device according to the present embodiment is shown in Fig. 13. Referring to Figs. 12 and 13, the robot device 9 according to the present embodiment includes a polishing tool 3 as a work tool.

[0135] The polishing tool 3 includes a pad 3a that contacts the surface 78a of the workpiece 78. The pad 3a has a circular planar shape. The polishing tool 3 is formed so that the pad 3a rotates around an axis of rotation that passes through the center of the circle. The polishing tool 3 is fixed to the flange 16 via a force sensor 24. The tool tip point can be set, for example, at the center of the surface where the main body of the polishing tool 3 contacts the pad 3a.

[0136] The operation control unit 43 sends an operation command to the tool driving unit 44 to drive the pad driving motor 23 that rotates the pad 3a. The tool driving unit 44 supplies electricity to the pad driving motor 23 based on the operation command. The measurement control unit 51 of the control device 4 in this embodiment measures the machining length of the workpiece 78 fixed to the fixing member 72.

[0137] 14 shows a side view of the robot, the polishing tool, and the workpiece when the robot in this embodiment is positioned at the first and second positions. The control device 4 polishes the surface 78a of the workpiece 78 by moving the polishing tool 3 in a direction along the surface 78a while keeping it in contact with the surface 78a, as indicated by arrow 95. Polishing the surface 78a of the workpiece 78 makes the workpiece 78 thinner.

[0138] The first position P1 is the position of the robot 1 when the polishing tool 3 supported by the robot before processing comes into contact with the workpiece 78 fixed to the fixing member 72. The second position P2 is the position of the robot 1 when the polishing tool 3 comes into contact with the workpiece 78 after processing.

[0139] When detecting each of the first position P1 and the second position P2, force control is performed by the force control unit 56. The force control unit 56 controls the position and attitude of the robot 1 so that the surface of the pad 3a comes into surface contact with the surface 78a of the workpiece 78. For example, the position and attitude of the robot 1 are controlled so that forces and moments other than forces in the direction along the rotation axis of the pad 3a approach zero at the tool tip point serving as the point of action.

[0140] First, a case where the temperature of the robot 1 changes will be described. The temperature detection unit 53 detects the measured temperature of the robot 1. The state detection unit 52 detects the first position P1 and the second position P2 of the robot. The change amount detection unit 54 detects the amount of change in position. Reference data showing the correlation between the amount of change in the robot's position and the measured temperature and the machining length is created in advance. The calculation unit 55 calculates the length of the measured portion based on the measured temperature, the amount of change in the robot's position, and the reference data. In this embodiment, the machining length in the thickness direction of the workpiece 77 polished by the polishing tool 3 can be calculated. When the temperature of the workpiece changes, the measured temperature of the workpiece can be detected, and the machining length in the thickness direction of the workpiece 77 can be calculated based on the reference data including the reference temperature of the workpiece.

[0141] The pad 3a gradually becomes thinner as the polishing proceeds. Therefore, the thickness of the pad that wears away can be calculated based on the pressure applied to the pad 3a and the polishing time. For example, the thickness of the pad that wears away in one polishing operation can be subtracted from the amount of change in the robot position.

[0142] In the robot control device of this embodiment, at least one of the measured temperature of the robot and the measured temperature of the workpiece is detected, and the machining length of the workpiece can be calculated with high accuracy based on the detected measured temperature.

[0143] In this embodiment, the polishing tool 3 is supported by the robot 1, and the workpiece 78 is fixed to the fixing member 72, but this is not limiting. The workpiece may be supported by the robot, and the polishing tool 3 may be fixed to a fixing device.

[0144] Other configurations, operations, and effects of the robot control device and robot device are similar to those of the robot control device and robot device of the first to fifth embodiments, and therefore will not be described repeatedly here.

[0145] In addition to the tasks described above, the measurement control unit of the above embodiment can be applied to a robot device that performs tasks that utilize the first and second positions of the robot. For example, the measurement control unit can be applied to a robot device that measures the flatness of a large surface of a workpiece. The robot device detects the robot's position by bringing a contact member into contact with multiple positions on the surface. If the measurement time is long, the temperature of the robot or the workpiece may change. For example, the temperature of the robot when measuring the first measurement point may differ from the temperature of the robot when measuring the last measurement point. A measurement control unit capable of performing the above temperature correction can be applied to such a robot device.

[0146] According to at least one of the above-described embodiments, it is possible to measure the length of a predetermined measurement portion or an angle relative to a predetermined measurement plane with high precision.

[0147] Although the present disclosure has been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the present disclosure or the spirit of the present disclosure derived from the content of the claims and their equivalents. These embodiments can also be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values ​​or mathematical expressions are used in the description of the above-described embodiments.

[0148] The following supplementary notes are disclosed regarding the above-described embodiment and modifications.

[0149] (Supplementary Note 1) A robot control device comprising: a temperature detection unit that detects at least one of a measured temperature of a robot and a measured temperature of a workpiece; a force control unit that performs force control of the robot; a state detection unit that detects the position and posture of the robot; a change amount detection unit that detects an amount of change in the position of the robot; and a calculation unit that calculates a length of a predetermined measurement portion, wherein the state detection unit detects a first position that is an initial position of the robot and a second position of the robot after the robot is driven by force control; the change amount detection unit detects the amount of change from the first position to the second position; a correlation between the amount of change and the length of the measurement portion with respect to the measured temperature is predetermined; and the calculation unit calculates the length of the measurement portion based on the measured temperature, the amount of change, and the correlation.

[0150] (Appendix 2) A robot control device according to Appendix 1 that measures the dimensions of a member supported by the robot or a member fixed to a fixed member, wherein the first position is the position of the robot when the member supported by the robot is separated from the member fixed to the fixed member, the second position is the position of the robot when the member supported by the robot and the member fixed to the fixed member come into contact, and the length of the measured portion is the dimension of the member supported by the robot or the member fixed to the fixed member.

[0151] (Supplementary Note 3) A robot control device according to Supplementary Note 1, which measures the machining length of a member supported by a robot or a member fixed to a fixed member, wherein the first position is the position of the robot when the member supported by the robot comes into contact with the member fixed to the fixed member before machining by driving the robot using force control, the second position is the position of the robot when the member supported by the robot comes into contact with the member fixed to the fixed member after machining by driving the robot using force control, and the length of the measurement portion is the machining length in the direction from the first position to the second position of the member supported by the robot or the member fixed to the fixed member.

[0152] (Supplementary Note 4) A robot control device for measuring the amount of movement of a slide member urged in a predetermined urging direction, the robot control device according to Supplementary Note 1, wherein the first position is the position of the robot when a pressing member supported by the robot contacts the slide member or when the pressing member supported by the robot is separated from the slide member, the second position is the position of the robot when the pressing member presses the slide member in a direction opposite to the urging direction with a predetermined force, and the length of the measurement portion is the amount of movement of the slide member in the direction opposite to the urging direction.

[0153] (Appendix 5) A robot control device according to any one of Appendices 1 to 4, wherein the correlation is determined based on previously measured reference data, the reference data includes a plurality of sets of a reference change amount related to the change amount, a reference temperature related to the measured temperature, and a reference length related to the length of the measured portion, and the calculation unit calculates the length of the measured portion by performing an interpolation or extrapolation calculation using the change amount and the measured temperature.

[0154] (Supplementary Note 6) A robot control device comprising: a temperature detection unit that detects at least one of a measured temperature of a robot and a measured temperature of a workpiece; a force control unit that performs force control of the robot; a state detection unit that detects the position and posture of the robot; a change amount detection unit that detects an amount of change in the posture of the robot; and a calculation unit that calculates an angle relative to a predetermined measurement plane, wherein the state detection unit detects a first posture that is an initial posture of the robot and a second posture of the robot after the robot is driven by force control; the change amount detection unit detects the amount of change from the first posture to the second posture; a correlation between the amount of change and the angle relative to the measurement plane with respect to the measured temperature is predetermined; and the calculation unit calculates the angle relative to the measurement plane based on the measured temperature, the amount of change, and the correlation.

[0155] (Appendix 7) A robot control device according to appendix 6, which measures a machining angle of a member supported by a robot or a member fixed to a fixed member, wherein the first posture is the posture of the robot when the member supported by the robot comes into surface contact with the member fixed to the fixed member before machining by driving the robot by force control, the second posture is the posture of the robot when the member supported by the robot comes into surface contact with the member fixed to the fixed member after machining by driving the robot by force control, and the angle relative to the measurement plane is a machining angle corresponding to an amount of change in the member supported by the robot or the member fixed to the fixed member.

[0156] (Appendix 8) A robot control device according to appendix 6 or 7, wherein the correlation is determined by reference data measured in advance, the reference data includes a plurality of sets of a reference change amount related to the change amount, a reference temperature related to the measured temperature, and a reference angle related to the angle related to the measured surface, and the calculation unit calculates the angle related to the measured surface by performing interpolation or extrapolation calculations using the change amount and the measured temperature.

[0157] REFERENCE SIGNS LIST 1 Robot 2 Hand 3 Polishing tool 4 Control device 5, 7, 8, 9 Robot device 19 Position detector 24 Force sensor 25 Temperature sensor 40 Control device main body 42 Memory unit 47 Reference data 51 Measurement control unit 52 State detection unit 53 Temperature detection unit 54 Change amount detection unit 55 Calculation unit 56 Force control unit 71, 72 Fixing member 75, 76 Workpiece 77 Workpiece 77b Spring 77c Slide member 78 Workpiece 78a Surface 81 Gauge 83 Contact member 83a Surface 84 Pressing member

Claims

1. A robot control device comprising: a temperature detection unit that detects at least one of a measured temperature of a robot and a measured temperature of a workpiece; a force control unit that performs force control of the robot; a state detection unit that detects the position and posture of the robot; a change amount detection unit that detects an amount of change in the position of the robot; and a calculation unit that calculates a length of a predetermined measurement portion, wherein the state detection unit detects a first position which is the initial position of the robot and a second position of the robot after the robot is driven by force control, the change amount detection unit detects the amount of change from the first position to the second position, a correlation between the amount of change and the length of the measurement portion relative to the measured temperature is predetermined, and the calculation unit calculates the length of the measurement portion based on the measured temperature, the amount of change, and the correlation.

2. A robot control device for measuring a dimension of a member supported by a robot or a member fixed to a fixed member, wherein the first position is a position of the robot when the member supported by the robot is away from a member fixed to the fixed member, the second position is a position of the robot when the member supported by the robot and the member fixed to the fixed member come into contact, and the length of the measurement portion is a dimension of the member supported by the robot or the member fixed to the fixed member, as described in claim 1.

3. A robot control device for measuring the machining length of a member supported by a robot or a member fixed to a fixed member, wherein the first position is a position of the robot when the member supported by the robot before machining comes into contact with a member fixed to a fixed member by driving the robot with force control, the second position is a position of the robot when the member supported by the robot after machining comes into contact with a member fixed to a fixed member by driving the robot with force control, and the length of the measurement portion is the machining length in the direction from the first position to the second position of the member supported by the robot or the member fixed to a fixed member.

4. A robot control device for measuring the amount of movement of a slide member biased in a predetermined biasing direction, wherein the first position is the position of the robot when a pressing member supported by the robot contacts the slide member or the position of the robot when the pressing member supported by the robot is separated from the slide member, the second position is the position of the robot when the pressing member presses the slide member in the opposite direction to the biasing direction with a predetermined force, and the length of the measurement portion is the amount of movement of the slide member in the opposite direction to the biasing direction.

5. A robot control device as described in any one of claims 1 to 4, wherein the correlation is determined in pre-measured reference data, the reference data including a plurality of sets of a reference amount of change related to the amount of change, a reference temperature related to the measured temperature, and a reference length related to the length of the measured portion, and the calculation unit calculates the length of the measured portion by performing an interpolation or extrapolation calculation using the amount of change and the measured temperature.

6. A robot control device comprising: a temperature detection unit that detects at least one of a measured temperature of a robot and a measured temperature of a workpiece; a force control unit that performs force control of the robot; a state detection unit that detects the position and posture of the robot; a change amount detection unit that detects an amount of change in the robot's posture; and a calculation unit that calculates an angle with respect to a predetermined measurement plane, wherein the state detection unit detects a first posture which is the initial posture of the robot and a second posture of the robot after the robot is driven by force control, the change amount detection unit detects the amount of change from the first posture to the second posture, a correlation between the amount of change and the angle with respect to the measurement surface with respect to the measured temperature is predetermined, and the calculation unit calculates the angle with respect to the measurement surface based on the measured temperature, the amount of change, and the correlation.

7. A robot control device for measuring a machining angle of a member supported by a robot or a member fixed to a fixed member, wherein the first posture is the posture of the robot when the member supported by the robot before machining comes into surface contact with a member fixed to a fixed member by driving the robot by force control, the second posture is the posture of the robot when the member supported by the robot after machining comes into surface contact with a member fixed to a fixed member by driving the robot by force control, and the angle with respect to the measurement plane is the machining angle corresponding to the amount of change of the member supported by the robot or the member fixed to a fixed member, as described in claim 6.

8. A robot control device as described in claim 6 or 7, wherein the correlation is determined by previously measured reference data, the reference data including a plurality of sets of a reference amount of change related to the amount of change, a reference temperature related to the measured temperature, and a reference angle related to the angle related to the measured surface, and the calculation unit calculates the angle related to the measured surface by performing an interpolation or extrapolation calculation using the amount of change and the measured temperature.

Images