JP2015089583A - Robot device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a space required for wiring, suppress life deterioration of the wiring, and suppress decrease of a temperature detection accuracy.SOLUTION: Each of plural temperature sensors 221 to 225 is disposed on each frame, and detects a temperature of each frame. A control apparatus 300 performs correction control of positional deviation of a robot arm based on the result detected by the plural temperature sensors 221 to 225. Respective the plural temperature sensors 221 to 225 are serially connected to the control apparatus 300 by cables 241 to 245, whereby a non-contact type temperature sensor which is not contact each frame and detects a temperature of each frame is provided.

Description

  The present invention relates to a robot apparatus that corrects and controls misalignment due to thermal expansion of a robot arm.

  The robot arm is configured by connecting a plurality of frames with joints. Each frame thermally expands due to heat generated during operation. Therefore, conventionally, a temperature sensor is attached to each of the multiple frames, and the error between the position of the tip of the robot arm that thermally expanded in each frame and the target position is calculated based on the temperature detected by each temperature sensor, and control is performed to eliminate the error. (See Patent Document 1). In Patent Document 1, each temperature sensor is connected to a signal converter via a signal line. Then, the output signal of each temperature sensor is converted into a digital signal by the signal converter and output to the control device.

JP-A-63-80305

  However, in Patent Document 1, as the number of temperature sensors increases, the number of wirings also increases and the wiring bundle becomes thick. Therefore, there is a problem of an increase in wiring routing space and a decrease in life due to wiring bending. Furthermore, since the temperature sensor is a contact-type temperature sensor that detects the temperature by contacting the frame, the temperature detection accuracy decreases due to variations in the contact state between the temperature sensor and the frame, thereby correcting the positional deviation of the robot arm tip. There was a problem that the accuracy of control was lowered.

  Therefore, an object of the present invention is to provide a robot apparatus that can suppress an increase in wiring routing space, suppress a decrease in wiring life, and suppress a decrease in temperature detection accuracy.

  The robot apparatus of the present invention includes a robot arm having a plurality of frames connected by joints, a plurality of temperature sensors for detecting the temperatures of the frames, and the robot arm based on detection results of the plurality of temperature sensors. Each temperature sensor is serially connected to the control device, arranged in a non-contact manner with respect to each frame, and opposed to each frame. It is a non-contact type temperature sensor for detecting the temperature of the water.

  According to the present invention, since each temperature sensor is serially connected to the control device, an increase in wiring routing space can be suppressed, and a reduction in life due to bending of the wiring can be suppressed. In addition, since each temperature sensor is a non-contact type temperature sensor, it is possible to suppress a decrease in temperature detection accuracy, and the accuracy of correction control for positional deviation of the robot arm by the control device is improved.

It is explanatory drawing which shows schematic structure of the robot apparatus which concerns on 1st Embodiment. It is explanatory drawing which shows the wiring state of the robot apparatus which concerns on 1st Embodiment. It is sectional drawing which shows the internal structure of one flame | frame among the some flame | frame of the robot apparatus which concerns on 1st Embodiment. It is sectional drawing which shows the internal structure of one flame | frame among the some flame | frame of the robot apparatus which concerns on 2nd Embodiment. It is sectional drawing which shows the internal structure of one flame | frame among the some flame | frame of the robot apparatus which concerns on 3rd Embodiment. It is sectional drawing which shows the internal structure of one flame | frame among the some flame | frame of the robot apparatus which concerns on 4th Embodiment. It is explanatory drawing which shows schematic structure of the robot apparatus which concerns on 5th Embodiment.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

[First Embodiment]
FIG. 1 is an explanatory diagram showing a schematic configuration of the robot apparatus according to the first embodiment of the present invention. FIG. 2 is an explanatory diagram showing a wiring state of the robot apparatus according to the first embodiment of the present invention. The robot apparatus 100 includes a vertical articulated robot 200 and a control apparatus 300 that controls the robot 200.

  As shown in FIG. 1, the robot 200 includes a multi-axis (four-axis) robot arm 201 and an end effector 202 attached to the tip of the robot arm 201. The robot arm 201 has a plurality (five) of frames (links) 211 to 215 connected by joints J1 to J4. The robot 200 includes a plurality of (five) temperature sensors 221 to 225 shown in FIG. 2 that are arranged on the frames 211 to 215 and detect the temperatures of the frames 211 to 215, respectively. Each of the temperature sensors 221 to 225 is a non-contact type temperature sensor. In the first embodiment, for example, a thermopile type infrared temperature sensor that detects a temperature by detecting infrared rays.

  The configuration of the robot arm 201 will be described in detail. As shown in FIG. 1, the frame 211 that is the first frame and the frame 212 that is the second frame are connected to each other by a joint J1 that is the first joint. ing. The frame 212 and the frame 213 that is the third frame are coupled so as to be able to turn at the joint J2 that is the second joint. The frame 213 and the frame 214, which is the fourth frame, are rotatably connected by a joint J3, which is a third joint. The frame 214 and the frame 215 that is the fifth frame are connected to each other so as to be rotatable at a joint J4 that is the fourth joint. The end effector 202 is attached to a frame 215 that is a front end frame (a front end link).

  Here, a substrate 231 that is a first printed wiring board is inside the frame 211, a substrate 232 that is a second printed wiring board is inside the frame 212, and a substrate 233 that is a third printed wiring board is inside the frame 213. Is arranged. A substrate 234 that is a fourth printed wiring board is disposed inside the frame 214, and a substrate 235 that is a fifth printed wiring board is disposed inside the frame 215. As shown in FIG. 2, temperature sensors 221 to 225 are mounted on the substrates 231 to 235, respectively.

  In addition, the substrates 231 to 235 (that is, the temperature sensors 221 to 225) are serially connected to the control device 300 via cables (wirings) 241 to 245 including power lines that transmit power and signal lines that transmit signals. That is, the control device 300 and the board 231 are connected by the cable 241 via the connector 251 as shown in FIG. The board 231 and the board 232 are connected by a cable 242 via connectors 252 and 253. The board 232 and the board 233 are connected by a cable 243 via connectors 254 and 255. Further, the substrate 233 and the substrate 234 are connected by a cable 244 via connectors 256 and 257. The board 234 and the board 235 are connected by a cable 245 through connectors 258 and 259. In this way, the substrates 231 to 235 (temperature sensors 221 to 225) are connected in a daisy chain by the cables 241 to 245 via the connectors 251 to 259. Specifically, there are at least two connectors on each of the boards 231 to 235, and daisy chain connection is established by connecting the connectors of the cables to the connectors on the boards.

  Here, in the portion passing through the joints J1 to J4 of the cables 242 to 245, the structure of the joints J1 to J4 is devised so that no load is applied to the cables 242 to 245 when the joints J1 to J4 are rotated. The shape is a round shape or crankshaft.

  The control device 300 corrects and controls misalignment of the robot arm 201 based on the detection results of the plurality of temperature sensors 221 to 225. More specifically, the control device 300 calculates an error between the position of the tip of the robot arm 201 and the target position when the frames 211 to 215 are thermally expanded by the temperatures detected by the temperature sensors 221 to 225. The joints J1 to J4 are controlled so as to eliminate the above.

  The substrate 231 has a wiring pattern (not shown) that electrically connects the connector 251 and the connector 252. The substrate 232 has a wiring pattern (not shown) that electrically connects the connector 253 and the connector 254. The substrate 233 has a wiring pattern (not shown) that electrically connects the connector 255 and the connector 256. The substrate 234 has a wiring pattern (not shown) that electrically connects the connector 257 and the connector 258.

  Here, each board | substrate 231-235 is the same structure, The connector 260 is formed in the board | substrate 235 although it is not used in this embodiment. The substrate 235 has a wiring pattern (not shown) that electrically connects the connector 259 and the connector 260.

  Further, the substrate 231 has a wiring pattern (not shown) that electrically connects the temperature sensor 221 to the connectors 251 and 252 via a resistor and a capacitor (not shown) that are mounted. The substrate 232 has a wiring pattern (not shown) that electrically connects the temperature sensor 222 to the connectors 253 and 254 via a mounted resistor and capacitor (not shown). The substrate 233 has a wiring pattern (not shown) that electrically connects the temperature sensor 223 to the connectors 255 and 256 via a mounted resistor and capacitor (not shown). The substrate 234 has a wiring pattern (not shown) that electrically connects the temperature sensor 224 to the connectors 257 and 258 via a mounted resistor and capacitor (not shown). The substrate 235 has a wiring pattern (not shown) that electrically connects the temperature sensor 225 to the connectors 259 and 260 via a mounted resistor and capacitor (not shown).

  That is, the cables 241 to 245 constitute a bus wiring connected to the control device 300, and the temperature sensors 221 to 225 are branched and connected to the bus wiring.

  Each of the temperature sensors 221 to 225 is a sensor module that constitutes an infrared temperature sensor, has a thermal element (not shown), and an AD converter (not shown), and outputs a temperature detection result as a digital signal. Each temperature sensor 221 to 225 outputs a digital signal to the control device 300 in time division so that the signals are synchronized with each other so that the signals do not overlap.

  FIG. 3 is a cross-sectional view showing an internal configuration of one frame (frame 211) among the plurality of frames 211 to 215 of the robot apparatus 100 according to the first embodiment of the present invention. Since the frames 212 to 215 have the same configuration, illustration and description are omitted.

  The temperature sensor 221 is mounted on the substrate 231 and is connected to cables 241 and 242 composed of power lines and signal lines. The temperature sensor 221 is disposed to face the inner surface of the frame 211 in a non-contact state with respect to the frame 211 and can detect the temperature of the inner surface of the frame 211 in a non-contact manner. Signals indicating the detected temperatures detected by the temperature sensors 221 to 225 are transmitted to the control device 300 via the cables 241 to 245.

  Here, the control device 300 has a function of correcting the position of the robot arm 201 using the temperatures detected by the temperature sensors 221 to 225. That is, the control device 300 calculates a length of each frame 211 to 215 from the detected temperature, and a forward kinematics to calculate the position of the tip of the robot arm 201 from the calculated length of the frames 211 to 215. And an arithmetic unit. Further, the control device 300 includes an inverse kinematics calculation unit that calculates a correction amount of the rotation angle (joint angle) of each joint J1 to J4 from the difference between the target position of the tip of the robot arm 201 and the calculated position; And a driver that controls to move by a movement amount based on the amount.

First, the amount of expansion of each frame 211 to 215 is calculated from the following equation in the frame length calculation unit.
ΔL1 = α1 × δ1 × L1 (1)
ΔL2 = α2 × δ2 × L2 (2)
ΔL3 = α3 × δ3 × L3 (3)
ΔL4 = α4 × δ4 × L4 (4)
ΔL5 = α5 × δ5 × L5 (5)

  Expression (1) is the expansion amount ΔL1 of the frame 211, Expression (2) is the expansion amount ΔL2 of the frame 212, Expression (3) is the expansion amount ΔL3 of the frame 213, Expression (4) is the expansion amount ΔL4 of the frame 214, 5) is a calculation formula for calculating the expansion amount ΔL5 of the frame 215.

Here, αi (i = 1, 2, 3, 4, 5) is a change amount of the frame temperature detected by the temperature sensors 221 to 225 from the reference temperature. The reference temperature is, for example, room temperature. δi (i = 1, 2, 3, 4, 5) is an expansion coefficient of the material of each of the frames 211 to 215. For example, in the case of a general aluminum alloy, it is 24 × 10 ⁻⁶ / ° C. As the expansion coefficient used here, when a plurality of materials of the frames 211 to 215 are formed, an average value thereof may be used. Moreover, Li (i = 1, 2, 3, 4, 5) is the length (frame length) of each frame 211-215, for example, shows the distance between the centers of joints. Since the frame length Li is a length for calculating the expansion amount, if there is a portion that does not contribute to thermal expansion, the length may be excluded. The lengths of the frames 211 to 215 whose temperature has changed are calculated by adding the expansion amount ΔLi of the frames 211 to 215 calculated as described above to the frame length Li.

  Next, the forward kinematics calculation unit calculates the position of the tip of the robot arm 201 by forward kinematics calculation from the calculation results of the lengths of the frames 211 to 215 and the rotation angles of the joints J1 to J4. A certain amount of displacement is calculated. Next, in the inverse kinematics calculation unit, the correction amount of the rotation angle of the joints J1 to J4 is calculated by the inverse kinematic calculation from the positional deviation amount with respect to the target position of the tip of the robot arm 201. Next, the driver instructs each motor to move to take into account the correction amount of the rotation angle of each joint, and drives the motor.

  As described above, since the temperature sensors 221 to 225 are serially connected, cables (wirings) passing through the joint can be configured with a minimum number regardless of the number of temperature sensors. Therefore, an increase in the cable (wiring) routing space can be suppressed, and a reduction in service life due to bending of the cable (wiring) can be suppressed. In addition, since non-contact temperature sensors are used as the temperature sensors 221 to 225, it is possible to prevent a decrease in temperature detection accuracy due to variations in the contact state, and the accuracy of positional deviation correction control of the tip of the robot arm 201 can be prevented. improves.

[Second Embodiment]
Next, a robot apparatus according to a second embodiment of the present invention will be described. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted. FIG. 4 is a cross-sectional view showing an internal configuration of one frame (frame 211) among the plurality of frames 211 to 215 of the robot apparatus according to the second embodiment of the present invention. Note that the frames 212 to 215 are the same as the frame 211, and thus the description and illustration are omitted.

  In the second embodiment, a high emissivity material 401 having an infrared emissivity higher than that of the frame 211 is formed on a part of the inner surface of the frame 211 (a position facing the light receiving surface of the temperature sensor 221). The frame 211 is made of an aluminum alloy, and the high emissivity material 401 is formed by applying, for example, a commercially available black body paint (emissivity 0.94), and at least the field of view of the temperature sensor 221 (dotted line in FIG. 3). Is formed in a region including a detection range R). In the second embodiment, the viewing angle of the temperature sensor 221 is 45 °, for example.

  As described above, since the high emissivity material 401 is formed on the inner surface of the frame 211 facing the temperature sensor 221, the amount of infrared rays emitted from the frame 211 is increased even if the frame 211 is a metal such as an aluminum alloy. Can do. Moreover, since the reflection of infrared rays due to the low emissivity can be prevented, the detection accuracy of the temperature sensor 221 is improved, and the frame temperature can be detected with high accuracy.

  In the second embodiment, the non-contact temperature sensor 221 has a viewing angle of 45 °. However, the application range of the high emissivity material may be changed according to the viewing angle. Moreover, although the example which apply | coated black body paint as a high emissivity material was shown, you may affix a commercially available black body tape.

  As described above, according to the robot apparatus of the second embodiment, the accuracy of the positional deviation correction control of the tip of the robot arm can be improved as in the first embodiment. In addition, even if the number of temperature sensors increases, the number of cables that pass through the joints does not change and can be configured with the minimum number of cables, so the increase in wiring routing space can be suppressed, and the life reduction due to wiring bending can be suppressed. it can.

  Furthermore, according to the robot apparatus of the second embodiment, since the high emissivity material 401 is formed on the inner surface of the frame 211 facing the temperature sensor 221, the heat dose (infrared ray amount) detected by the temperature sensor 221 increases. The detection accuracy of the frame temperature can be further improved.

[Third Embodiment]
Next, a robot apparatus according to a third embodiment of the invention will be described. In the third embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted. FIG. 5 is a cross-sectional view showing an internal configuration of one frame (frame 211) among the plurality of frames 211 to 215 of the robot apparatus according to the third embodiment of the present invention. Note that the frames 212 to 215 are the same as the frame 211, and thus the description and illustration are omitted.

  In the third embodiment, the rib 280 is formed on the inner surface of the frame 211 so as to surround the visual field range (detection range) R of the temperature sensor 221, and the high emissivity material 401 is applied to the inside thereof. That is, the frame 211 includes a bottom surface portion 211A that faces the temperature sensor 221 and a side surface portion 280A that protrudes from the bottom surface portion 211A toward the temperature sensor and surrounds the detection range R of the temperature sensor 221 together with the bottom surface portion 211A.

  Here, the rib 280 is formed by mold molding or machining, and the shape in the frame surface viewed from the temperature sensor 221 can be selected depending on the type of the temperature sensor 221, and can be a square shape or a circular shape. It may be.

  According to the robot apparatus of the third embodiment, the infrared rays of other components can be prevented from being reflected and the disturbance can be prevented within the viewing angle of the temperature sensor 221, so that the frame temperature is detected with high accuracy. be able to. Therefore, the accuracy of the positional deviation correction control at the tip of the robot arm is improved.

[Fourth Embodiment]
Next, a robot apparatus according to a fourth embodiment of the present invention will be described. In the fourth embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted. FIG. 6 is a cross-sectional view showing an internal configuration of one frame (frame 211) among the plurality of frames 211 to 215 of the robot apparatus according to the fourth embodiment of the present invention. Note that the frames 212 to 215 are the same as the frame 211, and thus the description and illustration are omitted.

  In the fourth embodiment, a recess 290 is formed on the inner surface of the frame 211 so as to surround the visual field range R of the temperature sensor 221, and a high emissivity material 401 is applied on the inside thereof.

  That is, the frame 211 includes a bottom surface portion 290A that faces the temperature sensor 221 and a side surface portion 290B that protrudes from the bottom surface portion 290A toward the temperature sensor and surrounds the detection range R of the temperature sensor 221 together with the bottom surface portion 290A.

  Also in the robot apparatus of the fourth embodiment, the frame temperature can be detected with high accuracy as in the third embodiment, and the accuracy of the positional deviation correction control of the tip of the robot arm can be improved.

[Fifth Embodiment]
Next, a robot apparatus according to a fifth embodiment of the invention will be described. In the fifth embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted. FIG. 7 is an explanatory diagram showing a schematic configuration of the robot apparatus according to the fifth embodiment of the present invention.

  A robot apparatus 100A according to the fifth embodiment includes a vertically articulated robot 200A and a control apparatus 300 that controls the robot 200A.

  The robot 200 </ b> A includes the robot arm 201 described in the first embodiment and the end effector 202.

  The robot arm 201 includes a plurality of motors M1 to M4 that respectively drive the joints J1 to J4 and a plurality of drive control boards 331 to 334 that respectively control the driving of the motors M1 to M4 in accordance with instructions from the control device 300. Have. A drive control board 335 that controls the drive of the motor of the end effector 202 is disposed in the frame 215.

  At least one temperature sensor among the plurality of temperature sensors 221 to 225 (see FIG. 2) is mounted on the drive control board. In the fifth embodiment, the temperature sensors 221 to 225 are mounted on the drive control boards 331 to 335 as in FIG. The drive control boards 331 to 335 are serially connected to the control device 300 (daisy chain connection).

  That is, the board on which the temperature sensor is mounted is not a board prepared for mounting the temperature sensor, but a drive control board for controlling the motors M1 to M4 that drive the joints J1 to J4 of the robot arm 201 ( A temperature sensor may be mounted on the distributed control board.

  As described above, by mounting the temperature sensor on the existing drive control boards 331 to 334 (335), it becomes possible to detect the frame temperature without adding a new board.

  The present invention is not limited to the embodiment described above, and many modifications are possible within the technical idea of the present invention.

  Although the case where the temperature sensor is disposed inside the frame has been described in the above embodiment, the temperature sensor may be disposed outside the frame as long as it is disposed facing the frame and is not in contact with the frame.

DESCRIPTION OF SYMBOLS 100 ... Robot apparatus, 200 ... Robot, 201 ... Robot arm, 211-215 ... Frame, 221-225 ... Temperature sensor, 300 ... Control apparatus, J1-J4 ... Joint

Claims (5)

A robot arm having a plurality of frames connected by joints;
A plurality of temperature sensors for detecting the temperature of each frame;
A control device that corrects and controls misalignment of the robot arm based on detection results of the plurality of temperature sensors; and
Each of the temperature sensors is a non-contact type temperature sensor that is serially connected to the control device, is disposed in a non-contact manner with respect to the frames, and is opposed to the frames, and detects the temperature of the frames. A robot device that is characterized.   The robot apparatus according to claim 1, wherein the temperature sensor is an infrared temperature sensor.   The robot apparatus according to claim 2, wherein a high emissivity material having an infrared emissivity higher than that of the frame is formed on each frame at a position facing each of the temperature sensors.   The frame includes a bottom surface portion facing the temperature sensor, and a side surface portion protruding from the bottom surface portion toward the temperature sensor and surrounding the detection range of the temperature sensor together with the bottom surface portion. The robot apparatus according to any one of claims 1 to 3. The robot arm includes a plurality of motors that respectively drive the joints, and a plurality of drive control boards that respectively control the driving of the motors according to instructions from the control device,
5. The robot apparatus according to claim 1, wherein at least one temperature sensor among the plurality of temperature sensors is mounted on the drive control board. 6.

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