Robotic system

Abstract

The present application relates to a robot system that enables a robot to operate stably in a low-temperature environment. The robot system (1) includes a robot (100) and a robot controller (500) that controls the operation and temperature of the robot (100). The robot (100) includes a joint (J5), a joint (J6), a drive mechanism (40-5) that drives the joint (J5), and a drive mechanism (40-6) that drives the joint (J6). The temperature regulator (300) includes a temperature sensor (310) that measures a first temperature of the drive mechanism (40-5), a heater (320) that heats the first drive section, a temperature sensor (310) that measures a second temperature of the drive mechanism (40-6), a heater (320) that heats the drive mechanism (40-6), and a regulation section (330) that controls the heat generation of the heater (320) so that the first temperature of the drive mechanism (40-5) approaches a first target value set in advance and controls the heat generation of the heater (320) so that the second temperature of the drive mechanism (40-6) approaches a second target value set in advance.

Description

Technical Field

[0001] This disclosure relates to robotic systems. Background Technology

[0002] Sometimes, robotic arms are made to perform the same tasks as humans. In such robotic arms, multiple arm elements are connected by joints. To make the joint movements smooth, as described in Patent Document 1, a lubricant is used on the actuators located at the joints.

[0003] In addition, in low-temperature environments such as frozen food production lines, which are relatively harsh for human workers, there is an urgent need to replace humans with robotic arms to perform the work.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2020-116716

[0005] However, if a robotic arm that operates in a normal temperature environment is directly placed in a low-temperature environment without considering the low-temperature environment as its working environment, it is conceivable that the robotic arm's smooth movement will become difficult due to the increased viscosity of the lubricant, and that the robotic arm will no longer be able to move when the lubricant solidifies. Summary of the Invention

[0006] According to one aspect of this disclosure, a robot system is provided. The robot system includes: a robotic arm; and a control unit for controlling the movement and temperature of the robotic arm. The robotic arm has: a first joint; a second joint, different from the first joint; a first drive unit for driving the first joint; and a second drive unit for driving the second joint, different from the first drive unit. The control unit includes: a first temperature measuring unit for measuring a first temperature of the first drive unit; a first heating unit for heating the first drive unit; a second temperature measuring unit for measuring a second temperature of the second drive unit, different from the first temperature measuring unit; a second heating unit for heating the second drive unit, different from the first heating unit; and an adjustment unit for controlling the heat output of the first heating unit to bring the first temperature of the first drive unit close to a preset first target value, and controlling the heat output of the second heating unit to bring the second temperature of the second drive unit close to a preset second target value. Attached Figure Description

[0007] Figure 1 This is a simplified diagram showing the overall structure of the robot system.

[0008] Figure 2 This is a block diagram showing the robot and the main components of the robot controller.

[0009] Figure 3 It is a decomposed 3D diagram of the arm element.

[0010] Figure 4 It is along Figure 3 The partial sectional view shown is taken when the arm element is cut along section line 4-4.

[0011] Figure 5 yes Figure 3 The side view of the arm element shown.

[0012] Figure 6 Observing from other directions Figure 3 The side view of the arm element shown.

[0013] Figure 7 This is a side view of other examples of arm elements.

[0014] Explanation of reference numerals in the attached figures

[0015] 1… Robot system, 10… Base, 20… Arm, 21, 22, 23, 24, 25, 26… Arm elements, 25c… Shaft, 31… Main body, 31a… Base, 31b… First front end, 31c… Second front end, 33… Connecting component, 33a… Cylindrical component, 33b… Cylindrical component, 40… Drive mechanism, 40-5… Drive mechanism, 40-6… Drive mechanism, 42… Motor, 44… Reducer, 70… End effector, 100… Robot, 300… Temperature regulator, 310… Temperature sensor, 320, 320a, 320b… Heaters, 330… Adjustment unit, 425… Motor 425b…rotary axis, 426…motor, 445…reducer, 445b…shaft, 446…reducer, 465…first pulley, 466…first pulley, 475…second pulley, 476…second pulley, 485…belt, 486…belt, 495…angle sensor, 496…angle sensor, 500…robot controller, 510…drive board, 515…motor driver, 520…control board, 521…memory, 523…CPU, 530…power board, J1, J2, J3, J4, J5, J6…joints, RC…robot coordinate system, RX, RY, RZ…angle position. Detailed Implementation

[0016] A1. Implementation method:

[0017] Figure 1This is a simplified diagram showing the overall configuration of the robot system 1 according to this embodiment. The robot system 1 includes a robot 100, a temperature regulator 300, and a robot controller 500. The robot 100 is also referred to as a robotic arm. The robot 100 is a vertical joint robot. The robot 100 performs operations related to food manufacturing in a food factory. In this embodiment, the robot 100 is set up in a low-temperature environment and operates in that environment. A low-temperature environment refers to an environment below 10°C, such as inside a cold storage room of a cold storage warehouse; more specifically, in this specification, it refers to an environment below -18°C, such as inside a freezer room of a frozen storage warehouse. It should be noted that the temperature regulator 300 and the robot controller 500 are set up in a normal temperature environment. In this specification, a normal temperature environment refers to an environment in the range of 15–25°C, such as outside a cold storage room of a cold storage warehouse or outside a freezer room of a frozen storage warehouse.

[0018] The robot controller 500 is connected to the robot arm 20 and the end effector 70 via signal lines. The robot controller 500 controls the position of the control points of the robot 100 in the robot coordinate system (RC). The control points of the robot 100 are, for example, set at the center of the point where the end effector 70 contacts the object. Sometimes the control point is referred to as the TCP (Tool Center Point). The robot controller 500 drives the robot 100, causing changes in the position and posture of the robot 100. Therefore, the robot controller 500 can position the end effector 70, mounted at the tip of the robot arm 20, in a specified posture at a specified location. For example, the robot controller 500 can communicate with a control device (not shown) to control the robot arm 20 and the end effector 70 according to motion commands received from the control device. The control device is, for example, a programmable logic controller (PLC).

[0019] In this embodiment, the coordinate system defining the space in which the robot 100 is positioned, with the base 10 as the reference, is referred to as the robot coordinate system RC. The robot coordinate system RC is a three-dimensional Cartesian coordinate system defined on a horizontal plane by mutually orthogonal X-axis and Y-axis, and a Z-axis with vertically upward as the positive direction. Any position in the robot coordinate system RC can be represented by the position along the X-axis, Y-axis, and Z-axis. Furthermore, the angular position of rotation about the X-axis is denoted as RX, the angular position of rotation about the Y-axis as RY, and the angular position of rotation about the Z-axis as RZ. Any posture in the robot coordinate system RC can be represented by the angular positions RX, RY, and RZ.

[0020] The robot 100 includes a base 10, an arm 20, and an end effector 70. The base 10 supports the components constituting the robot 100. The robot 100 is mounted on the floor by fixing the base 10 to the floor. Additionally, although... Figure 1 The illustration is omitted, but the robot 100 receives power from an external AC power source.

[0021] Arm 20 includes arm elements 21, 22, 23, 24, 25, and 26. Additionally, arm 20 has six joints J1 to J6. Joints J1 to J6 are rotary joints. Arm element 21 is connected to the upper end of base 10. The connection between base 10 and arm element 21 forms joint J1. Arm element 21 rotates relative to base 10 about the rotation axis of joint J1. Arm element 22 is connected to the front end of arm element 21. The connection between arm element 21 and arm element 22 forms joint J2. Arm element 22 rotates relative to arm element 21 about the rotation axis of joint J2. Arm element 23 is connected to the front end of arm element 22. The connection between arm element 22 and arm element 23 forms joint J3. Arm element 23 rotates relative to arm element 22 about the rotation axis of joint J3. Arm element 24 is connected to the front end of arm element 23. The connection between arm element 23 and arm element 24 forms joint J4. Arm element 24 rotates relative to arm element 23 about the rotation axis of joint J4. Arm element 25 is connected to the front end of arm element 24. The connection between arm element 24 and arm element 25 forms joint J5. Arm element 25 rotates relative to arm element 24 about the rotation axis of joint J5. Arm element 26 is connected to the front end of arm element 25. The connection between arm element 25 and arm element 26 forms joint J6. Arm element 26 rotates relative to arm element 25 about the rotation axis of joint J6. Joint J6 rotates around an axis perpendicular to the rotation axis of joint J5. Details regarding the structure of the arm elements will be described later.

[0022] An end effector 70 is mounted on arm element 26 via a force sensor (not shown). The end effector 70 is, for example, a device for gripping a workpiece (not shown). Figure 1 In this diagram, for ease of understanding, the end effector 70 is shown as a cylindrical component. The end effector 70 is controlled by the robot controller 500.

[0023] The temperature regulator 300 regulates the temperature of the six drive mechanisms 40 of joints J1 to J6 of the arm 20 of the drive robot 100. Specifically, the temperature regulator 300 heats the six drive mechanisms 40 via corresponding heaters 320 to maintain the target temperature specified by the robot controller 500. The temperature regulator 300 is capable of individually adjusting the temperature at all six points. The temperature regulator 300 includes six temperature sensors 310, six heaters 320, and an adjustment unit 330. It should be noted that in Figure 1 The illustrations of the six temperature sensors 310 and six heaters 320 are omitted. Additionally, the temperature regulator 300 is connected to the robot controller 500 via signal lines. Furthermore, although in... Figure 1 The illustration is omitted, but the temperature regulator 300 receives power from an external AC power source.

[0024] Figure 2 This is a block diagram showing the main components of the robot 100, temperature regulator 300, and robot controller 500. Each drive mechanism 40 is equipped with a temperature sensor 310 and a heater 320. Figure 2 The diagram only shows two drive mechanisms 40, two temperature sensors 310, and two heaters 320. The temperature sensors 310 are, for example, thermocouples or resistive temperature sensors. The temperature sensors 310 measure the temperature near the corresponding drive mechanism 40. In this specification, the temperature measured by the temperature sensors 310 of the corresponding drive mechanism 40 includes the temperature measured near the corresponding drive mechanism 40. The heaters 320 are, for example, heaters with a nichrome heating wire covered by a thin metal film as the heating element. The heaters 320 are heated by being supplied with current. The heaters 320 heat the corresponding drive mechanism 40. In this specification, the heaters 320 heating the corresponding drive mechanism 40 includes the heaters 320 heating the area near the corresponding drive mechanism 40. Six temperature sensors 310 and six heaters 320 are positioned at defined locations on the arm 20. Details regarding the placement of the temperature sensors 310 and heaters 320 are described later.

[0025] The regulating unit 330 controls the heat output of each heater 320 for each of the six drive mechanisms 40 based on the temperature measured by the temperature sensor 310, so that the temperature of the drive mechanism 40 is close to the target temperature. Controlling the heat output of the heater 320 also includes reducing the heat output to zero, i.e., turning off the heater 320. The target temperature is the temperature that is desired to be maintained for the drive mechanism 40. The regulating unit 330 controls the heat output of the heater 320, for example, using PID (Proportional Integral Differential) control, so that the measured temperature is close to the target temperature, i.e., the deviation between the measured temperature and the target temperature is close to 0. In this specification, the ambient temperature at which the robot 100 can operate normally is set to 0 to 45°C. The target temperature is preferably within the range of the ambient temperature at which the robot 100 can operate normally. For example, the target temperature is 10°C. Here, the heat output of the heater 320 refers to the heat output per unit time. The robot controller 500 and the temperature regulator 300 are also collectively referred to as the control unit. In addition, the adjustment unit 330 outputs the temperature measurement values ​​measured by the six temperature sensors 310 to the control board 520 of the robot controller 500 at predetermined time intervals.

[0026] The robot controller 500 includes a drive board 510, a control board 520, and a power supply board 530. The drive board 510 has six motor drivers 515. Each motor driver 515 drives the motor 42 of the corresponding drive mechanism 40 in the six drive mechanisms 40. The drive board 510 drives the six motors 42 according to the control of the control board 520. The drive board 510 is disposed inside the arm 20.

[0027] The control board 520 includes a memory 521 and a CPU (Central Processing Unit) 523. The memory 521 stores programs and data used by the robot controller 500 for various processes. For example, the memory 521 stores motion programs that control the movements of the robot 100 and the target temperature values ​​for each of the six drive mechanisms 40. The CPU 523 performs various functions by executing the programs stored in the memory 521.

[0028] For example, the CPU 523 sets a target value representing the target temperature in the adjustment unit 330 of the temperature regulator 300 for each of the six drive mechanisms 40. In this embodiment, it is assumed that the target temperature of the six drive mechanisms 40 is the same. The robot controller 500 is also referred to as the control unit.

[0029] The power supply board 530 converts power supplied from an external AC power source into DC power and supplies the converted power to the control board 520. The power supply board 530 includes a circuit that steps down the power supplied from the external AC power source and converts the stepped-down power back into DC power. The control board 520 and the power supply board 530 are disposed inside the housing of the robot controller 500.

[0030] Figure 3 This is an exploded stereoscopic view of arm element 24. For ease of understanding of the technology, in... Figure 3 The diagram of a portion of the composition of arm element 24 is omitted. Figure 4 It is along Figure 3 The partial sectional view shown is taken when section arm element 24 is cut along section line 4-4. Figure 3 , Figure 4 The illustration of the end effector 70 is omitted. Figure 5 Observed in the -X direction Figure 3 The side view of arm element 24 shown. Figure 5 This is a side view of the main body 31 of arm element 24 after the +X side has been removed. Figure 5 In order to show the positional relationship between the motor 425, the first pulley 465, the second pulley 475, and the belt 485, the illustrations of other constituent elements are omitted. Figures 3-6 In this context, a Cartesian coordinate system, different from the robot's RC coordinate system, is used for convenience. Figures 3-6 The rectangular coordinate system set in the middle is a coordinate system fixed relative to arm element 24.

[0031] Arm element 24 has a main body 31, a connecting component 33, and a drive mechanism 40. The main body 31 is a hollow shell formed of aluminum or an aluminum alloy. Figure 3 , Figure 4 As shown, in arm element 24, the main body 31 includes a base 31a, a first front end portion 31b, and a second front end portion 31c. The first front end portion 31b and the second front end portion 31c are formed to extend from the base 31a in the +Y direction. It should be noted that the shape of the main body 31 of arm elements other than arm element 24 is configured according to the joints of each arm element.

[0032] The connecting member 33 connects the arm element 24 and the arm element 25. In the arm element 24, the connecting member 33 includes a cylindrical member 33a and a cylindrical member 33b. The arm element 25 is disposed between a first front end portion 31b and a second front end portion 31c. The cylindrical member 33a is disposed between the first front end portion 31b and the arm element 25. The cylindrical member 33a is fixed to the first front end portion 31b by inserting into an opening formed on the +X side of the first front end portion 31b. The cylindrical member 33b is disposed between the second front end portion 31c and the arm element 25. The cylindrical member 33b is fixed to the second front end portion 31c by inserting into an opening formed on the -X side of the second front end portion 31c.

[0033] The first front end portion 31b and the second front end portion 31c, along with the cylindrical components 33a and 33b, form a joint structure. The arm element 25 is clamped into the cylindrical components 33a and 33b, thereby being held by the arm element 24. The arm element 25 is rotatable in its configured position. It should be noted that the number and shape of the connecting members 33 constituting the arm element other than the arm element 24 are determined according to the joints of that arm element.

[0034] Drive mechanism 40 drives the corresponding joints J1 to J6. Sometimes, drive mechanism 40 of arm element 24 is referred to as drive mechanism 40-5. Drive mechanism 40-5 drives joint J5. Drive mechanism 40 (drive mechanism 40-5) of drive joint J5 includes a motor 425, a reducer 445, a first pulley 465, a second pulley 475, a belt 485, and an angle sensor 495. Motor 425 is motor 42 of drive mechanism 40-5. Reducer 445 is reducer 44 of drive mechanism 40-5. Angle sensor 495 is angle sensor 49 of drive mechanism 40-5. Figure 3 The diagrams of the reducer 445 and the angle sensor 495 are omitted. Figure 4 The internal structure of the motor 425 and reducer 445, as well as the angle sensor 495, are omitted from the diagram.

[0035] Motor 425 drives joint J5, thus rotating the rotation axis 425b under the control of robot controller 500. Motor 425 is, for example, a servo motor. Reducer 445 converts the rotational input from motor 425 into a low-speed rotational output. First pulley 465 is connected to the rotation axis 425b of motor 425. Second pulley 475 is supported by the shaft portion 445b of reducer 445. Figure 4 As shown, the reducer 445 is connected to the shaft portion 25c, which is integrally formed with the arm element 25. As... Figure 3 , Figure 5As shown, belt 485 is mounted between the first pulley 465 and the second pulley 475. Therefore, the rotational force of motor 425 can be transmitted to arm element 25.

[0036] like Figure 2 As shown, angle sensor 49 (495) detects the angular position of the output shaft of motor 425 as the rotation angle of joint J5, and outputs the detected value to the control board 520 of robot controller 500. Angle sensor 49 is, for example, a rotary encoder. Alternatively, angle sensor 49 is a battery-free encoder that does not require a battery for storing the detected value, such as a battery-free encoder using a structure with multiple gears. Specifically, angle sensor 49 has a main shaft gear mounted on the output shaft of motor 425 and first to third auxiliary shaft gears meshing with the main shaft gear, and the number of teeth of the four gears is an integer that does not have a greatest common divisor other than 1. Angle sensor 49 detects the angular position within one revolution and the number of revolutions as the rotation angle based on the combination of the positions of the four gears. It should be noted that angle sensor 49 can also be other battery-free encoders, for example, a battery-free encoder that uses a power generation unit that utilizes magnetic force to store the detected value in memory.

[0037] Arm elements 21 to 23 also have a main body 31, a connecting member 33, and a drive mechanism 40, respectively. The drive mechanism 40 of arm element 21 drives joint J2. The drive mechanism 40 of arm element 22 drives joint J3. The drive mechanism 40 of arm element 23 drives joint J4. In addition, the drive mechanism 40 of the drive joint J1 is disposed inside the base 10.

[0038] Furthermore, no drive mechanism 40 is provided inside the arm element 26. Therefore, in addition to the drive mechanism 40 for driving joint J5, other drive mechanisms 40 for driving joint J6 are also provided inside the arm element 24.

[0039] Figure 6 Observed in the +X direction Figure 3 The side view of arm element 24 shown. Figure 6 This is a side view of the main body 31 of arm element 24 with the -X side side removed. Figure 6The diagram shows a drive mechanism 40 for driving joint J6. Sometimes, the drive mechanism 40 for driving joint J6 is referred to as drive mechanism 40-6. The drive mechanism 40 (40-6) for driving joint J6 includes a motor 426, a reducer 446, a first pulley 466, a second pulley 476, a belt 486, and an angle sensor 496. Motor 426 is the same as motor 42 in drive mechanism 40-6. Reducer 446 is the same as reducer 44 in drive mechanism 40-6. Angle sensor 496 is the same as angle sensor 49 in drive mechanism 40-6. Figure 6 In this diagram, to illustrate the positional relationship between the motor 426, the first pulley 466, the second pulley 476, and the belt 486, illustrations of other constituent elements are omitted. Joint J6 rotates about an axis of rotation intersecting the rotational axis of the motor 426. Therefore, the reducer 446, including hypoid gears, worm gears, and other bevel gears, converts the rotational direction of the power transmitted from the motor 426 to a substantially perpendicular direction. Simultaneously, the reducer 446 reduces the rotational speed of the power input from the motor 426.

[0040] Next, the locations of the temperature sensor 310 and the heater 320 in the temperature regulator 300 will be explained. For example... Figure 3 , Figure 5 As shown, in arm element 24, the temperature sensor 310 and heater 320 of the drive mechanism 40 (drive mechanism 40-5) for driving joint J5 are disposed between the motor 425 and the reducer 445 and inside the bottom surface of the main body 31. For example, the temperature sensor 310 and heater 320 are disposed at the midpoint of the straight line connecting the motor 425 and the reducer 445.

[0041] As previously described, the main body 31 is formed of aluminum or an aluminum alloy. Therefore, heat generated from the heater 320 is conducted through the main body 31. As a result, the motor 425 and the reducer 445 are heated. Joint J5 is also referred to as the first joint. The drive mechanism 40-5 that drives joint J5 is also referred to as the first drive unit. The motor 425 is also referred to as the first motor. The reducer 445 is also referred to as the first reducer. The temperature of the drive mechanism 40-5 is also referred to as the first temperature. The target temperature of the drive mechanism 40-5 is also referred to as the first target value. The temperature sensor 310 that measures the temperature of the drive mechanism 40-5 is also referred to as the first temperature measuring unit. The heater 320 that heats the drive mechanism 40-5 is also referred to as the first heating unit.

[0042] In addition, such as Figure 6As shown, in arm element 24, the temperature sensor 310 and heater 320 of the drive mechanism 40 (drive mechanism 40-6) for driving joint J6 are disposed between the motor 426 and the reducer 446 and on the inner side of the upper surface of the main body 31. For example, the temperature sensor 310 and heater 320 are disposed at the midpoint of the straight line connecting the motor 426 and the reducer 446. Heat generated from the heater 320 is conducted through the main body 31. As a result, the motor 426 and the reducer 446 are heated. Joint J6 is also referred to as the second joint. The drive mechanism 40-6 that drives joint J6 is also referred to as the second drive unit. The motor 426 is also referred to as the second motor. The reducer 446 is also referred to as the second reducer. The temperature of the drive mechanism 40-6 is also referred to as the second temperature. The target temperature of the drive mechanism 40-6 is also referred to as the second target value. The temperature sensor 310 that measures the temperature of the drive mechanism 40-6 is also referred to as the second temperature measuring unit. The heater 320 that heats the drive mechanism 40-6 is also referred to as the second heating unit.

[0043] Additionally, the temperature sensor 310 and heater 320 of the drive mechanism 40 for driving joint J1 are disposed inside the base 10, between the motor 42 and the reducer 44, and on the inner wall of the base 10. The temperature sensor 310 and heater 320 of the drive mechanism 40 for driving joint J2 are disposed inside the main body of arm element 21, between the motor 42 and the reducer 44, and on the inner side of the main body of arm element 21. The temperature sensor 310 and heater 320 of the drive mechanism 40 for driving joint J3 are disposed inside the main body of arm element 22, between the motor 42 and the reducer 44, and on the inner side of the main body of arm element 22. The temperature sensor 310 and heater 320 of the drive mechanism 40 for driving joint J4 are disposed inside the main body of arm element 23, between the motor 42 and the reducer 44, and on the inner side of the main body of arm element 23.

[0044] Thus, a temperature sensor 310 and a heater 320 are provided for the drive mechanism 40 that drives each joint. The temperature regulator 300 individually controls the heat output of the heater 320 for each drive mechanism 40 so that the measured temperature is close to the target temperature, that is, the deviation between the measured temperature and the target temperature is close to 0.

[0045] As explained above, in the configuration of the embodiment, heating the drive mechanism 40 prevents the lubricant used in the drive mechanism 40 from solidifying and rendering the robot 100 unable to move. Furthermore, even if the lubricant does not solidify, its viscosity increases as the temperature decreases. Even lubricants designed for low-temperature environments exhibit increased viscosity with decreasing temperature. When the lubricant viscosity increases, the robot 100 will find it difficult to move smoothly. Additionally, when the lubricant viscosity increases, for example, the slippage of the bearings used in the reducer 44 of the drive mechanism 40 deteriorates, resulting in energy loss. However, by heating each drive mechanism 40, such problems can be suppressed.

[0046] In this way, the heating of each drive mechanism 40 is individually controlled based on the temperature measured near each drive mechanism 40. Therefore, compared to heating all drive mechanisms 40 uniformly, each drive mechanism 40 can be heated appropriately. As a result, each drive mechanism 40 can operate stably in low-temperature environments.

[0047] Furthermore, in the robot 100, the main body 31 of the arm element is sometimes formed of aluminum or aluminum alloy, while gears, bearings, etc., which constitute part of the drive mechanism 40 are formed of iron. When the robot 100 is moved from a normal temperature environment to a low temperature environment, the shrinkage rate of each component will differ due to the difference in the coefficients of thermal expansion of aluminum and iron. As a result, the arm 20 will warp and tilt. However, since the control is to heat the drive mechanism 40 of the robot 100, the temperature of the robot 100 is maintained within the temperature range that allows it to operate normally, thus suppressing the shrinkage of the components.

[0048] In addition, since a heater 320 is provided between the motor 42 and the reducer 44 in the drive mechanism 40, both the motor 42 and the reducer 44 can be heated simultaneously by a single heater 320.

[0049] In addition, such as Figure 3 , Figure 5 As shown, the temperature sensor 310 is configured to measure the temperature at a predetermined distance L1 between the location where the motor 425 is located and the location where the reducer 445 is located, separated from the motor 425. This predetermined distance L1 between the temperature sensor 310 and the motor 425 is also referred to as the first distance. Figure 6As shown, the temperature sensor 310 is configured to measure the temperature at a location between the position where the motor 426 is located and the position where the reducer 445 (not shown) is located, separated from the motor 426 by a predetermined distance L2. This predetermined distance L2 between the temperature sensor 310 and the motor 426 is also referred to as the second distance. It should be noted that distances L1 and L2 can be the same or different. In this way, each temperature sensor 310 is positioned at a distance from the motor 425 included in the drive mechanism 40, which is the object of measurement. Therefore, it is possible to suppress errors caused by the heat generated by the motor 425 in the measured temperature value of the drive mechanism 40.

[0050] B1. Other implementation methods 1

[0051] In this implementation, a target temperature is set for each of the six drive mechanisms 40, and temperature control is performed to bring the measured temperature close to the target temperature. Alternatively, an upper limit and a lower limit value for the target temperature can be set for each of the six drive mechanisms 40. The lower limit value for the target temperature set for drive mechanism 40-5 is referred to as the first lower limit value. The upper limit value for the target temperature set for drive mechanism 40-5 is referred to as the first upper limit value. The lower limit value for the target temperature set for drive mechanism 40-6 is referred to as the second lower limit value. The upper limit value for the target temperature set for drive mechanism 40-6 is referred to as the second upper limit value.

[0052] Specifically, the robot controller 500 sets the target temperature for each of the six drive mechanisms 40 as the midpoint of a range defined by an upper and lower temperature limit, and sets this target temperature in the temperature regulator 300. The temperature regulator 300 outputs the temperature measurements from the six temperature sensors 310 to the robot controller 500. If the received measurement value is not between the lower and upper limits set for that drive mechanism 40, the robot controller 500 changes the target temperature for that drive mechanism 40 and sets the changed target temperature in the temperature regulator 300.

[0053] For example, if the received measurement value is lower than the lower limit and the difference between the measurement value and the lower limit is greater than or equal to a predetermined first value, the robot controller 500 sets a temperature higher than the previously set target temperature as the new target temperature and sets it in the temperature regulator 300. Conversely, if the received measurement value exceeds the upper limit and the difference between the measurement value and the upper limit is greater than or equal to a predetermined second value, the robot controller 500 sets a temperature lower than the previously set target temperature as the new target temperature and sets it in the temperature regulator 300. On the other hand, if the difference between the measurement value and the lower limit is not greater than the first value, or the difference between the measurement value and the upper limit is not greater than the second value, the robot controller 500 does not change the target temperature. This is because, if the difference between the upper or lower limit and the measurement value is considered small, it is assumed that even without changing the target temperature, the PID control of the temperature regulator 300 will bring the temperature of the drive mechanism 40 into an appropriate range.

[0054] Alternatively, if the received measurement value remains below the lower limit for a defined period, the robot controller 500 sets a temperature higher than the previously set target temperature as the new target temperature and sets it in the temperature regulator 300. Alternatively, if the received measurement value exceeds the upper limit for a defined period, the robot controller 500 sets a temperature lower than the previously set target temperature as the new target temperature and sets it in the temperature regulator 300.

[0055] In this way, by controlling the temperature of each drive mechanism 40 to be maintained within a set range according to the temperature of each drive mechanism 40, each drive mechanism 40 can operate stably.

[0056] B2. Other implementation methods 2

[0057] In one implementation, the target temperature of the six drive mechanisms 40 is the same, but it can also be set that the target temperatures of the six drive mechanisms 40 are different.

[0058] The advantages of having different target temperatures for the six drive mechanisms 40 are explained below. First, in the robot 100, the motor capacities of the motors 42 in each of the drive mechanisms 40 of the arm element are different. The motor capacity of the motor 42 located at the root of the arm 20 is larger than that of the motor 42 located at the tip of the arm 20. For example, the motor 42 located at the root of the arm 20 drives the joint J1 formed by the connection between the base 10 and the arm element 21. For example, the motor 42 located at the tip of the arm 20 drives the joint J6. The reason for this difference in motor capacity is as follows: The motor 42 located at the root of the arm 20 needs to support other arm elements. On the other hand, the motor 42 located at the tip of the arm 20 does not need to support other arm elements.

[0059] When all six motors 42 perform the same workload, the heat generated per unit time by each motor 42 is proportional to its motor capacity. Therefore, the motor 42 located at the front end of the arm 20 generates less heat per unit time compared to the motor 42 located at the root end of the arm 20. Consequently, even if the arm elements at the front end and root end are heated in the same way, the rate of temperature rise per unit time caused by heating the arm elements at the front end is smaller than that caused by heating the arm elements at the root end. Therefore, the target temperature of the arm elements at the front end can be set higher than the target temperature of the arm elements at the root end.

[0060] Furthermore, when the motor capacities of the six motors 42 are equal, the heat generated per unit time by each motor 42 is proportional to its workload per unit time. For example, suppose that the workload of the motor 42 located at the root side of the arm 20 is greater than that of the motor 42 located at the front end of the arm 20. In this case, the rate of temperature rise per unit time caused by heating the arm element at the root side is greater than the rate of temperature rise per unit time caused by heating the arm element at the front end. Therefore, the target temperature of the arm element at the front end can be set higher than the target temperature of the arm element at the root side. Furthermore, the adjustment unit 330 can also control the heat generated per unit time of the heater 320 heating the arm element at the front end to be greater than the heat generated per unit time of the heater 320 heating the arm element at the root side.

[0061] For example, suppose that the workload of the motor 42 located at the front end of the arm 20 is greater than that of the motor 42 located at the root end of the arm 20. In this case, the rate of temperature rise per unit time caused by heating the arm element at the front end is greater than the rate of temperature rise per unit time caused by heating the arm element at the root end. Therefore, the target temperature of the arm element at the root end can be set higher than the target temperature of the arm element at the front end. Furthermore, the adjustment unit 330 can also control the heating of the heater 320 heating the arm element at the root end to be greater per unit time than the heating of the heater 320 heating the arm element at the front end.

[0062] Furthermore, for example, when the object held by the robot 100 is a low-temperature object such as frozen food, the heat capacity of the arm element 26 closest to the end effector 70 is greater than that of the other arm elements. In this case, the rate of temperature rise per unit time caused by heating the arm element 26 is smaller than the rate of temperature rise per unit time caused by heating the other arm elements. Therefore, the target temperature of the arm element 26 can be set higher than the target temperature of the other arm elements.

[0063] B3. Other implementation methods 3

[0064] Furthermore, the heat output of heater 320 per unit time can also be calculated as follows. The workload of drive mechanism 40 is pre-calculated by a computer based on the motion program controlling the actions of robot 100. Specifically, for example, regarding each instruction included in the motion program, the workload of motor 42 driving each joint is calculated based on the displacement of each joint of robot 100 during instruction execution, as well as the rotational speed and torque of motor 42. Then, the heat output of motor 42 per unit time is obtained by dividing the sum of the workloads of each joint during motion program execution by the time taken to complete the motion program execution. Furthermore, the heat output of heater 320 per unit time corresponding to the heat output of motor 42 per unit time is obtained. In this case, robot controller 500 can also control temperature regulator 300 to heat the robot using the calculated heat output of motor 42 per unit time.

[0065] Therefore, each drive mechanism 40 is heated with a heat output per unit time that is proportional to the heat output of each drive mechanism 40 and corresponds to the workload in each drive mechanism 40. In this way, since each drive mechanism 40 is heated with the required amount according to the workload of each drive mechanism 40, the drive section can be heated efficiently.

[0066] B4. Other implementation methods 4

[0067] In this embodiment, an example is described where the temperature sensor 310 and the heater 320 are positioned at the midpoint of the straight line connecting the motor 42 and the reducer 44. However, the temperature sensor 310 and the heater 320 may not be positioned at the midpoint. The temperature sensor 310 and the heater 320 may also be positioned closer to the larger of the motor 42 and the reducer 44. Here, the larger of the motor 42 and the reducer 44 refers to the one with the larger volume. By placing the heater 320 closer to the larger of the motor 42 and the reducer 44 rather than the smaller one, the motor 42 and the reducer 44 can be heated evenly.

[0068] B5. Other implementation methods 5

[0069] In this embodiment, an example in which each temperature sensor 310 is arranged at a distance from the motor 425 included in the drive mechanism 40, which is the object of measurement, has been described. However, the temperature sensors 310 may also be arranged without being separated from the motor 425 included in the drive mechanism 40, which is the object of measurement. For example, the heat generated by the motor 42 can be pre-calculated using computer simulation or the like as a correction value. The CPU 523 of the control board 520 may also obtain the temperature measurement value of the drive mechanism 40 by subtracting the correction value from the measurement value of the temperature sensor 310 supplied by the adjustment unit 330.

[0070] B6. Other implementation methods 6

[0071] Furthermore, each heater 320 has a fuse that cuts off or limits the supplied current based on temperature rise. The fuses of the heaters 320 in the heating drive mechanism 40-5 are referred to as first protective elements. The fuses of the heaters 320 in the heating drive mechanism 40-6 are referred to as second protective elements. Because each heater 320 has a fuse, it is possible, for example, to stop supplying current to the heater 320 regardless of the control of the regulating unit 330. Therefore, overheating of the drive mechanism 40 can be prevented. For example, if the motor 42 is a servo motor, the motor 42 has an encoder. Assume the encoder's maximum temperature is 100°C. In such a case, by using a fuse with a melting point of 80°C, it is possible to prevent the drive mechanism 40 from overheating to the point that the encoder of the motor 42 reaches its maximum temperature.

[0072] B7. Other implementation methods 7

[0073] Additionally, the robot controller 500 may sometimes be instructed to stop the robot 100 while it is performing an action. For example, this can be done by pressing an emergency stop button located at the workpiece loading inlet, which instructs the robot controller 500 to stop the robot 100. In this case, the robot controller 500 instructs the temperature regulator 300 to stop heating. Consequently, the temperature regulator 300 stops heating from the six heaters 320 configured on the arm 20. By stopping heating along with the cessation of the robot 100's action, unnecessary heating of each drive mechanism 40 is avoided.

[0074] Furthermore, the circuits supplying power from the power source to each drive mechanism 40 can be configured to be different from the circuits supplying power from the power source to the heater 320. For example, sometimes, in response to a signal from a sensor detecting whether there is a person around the robot 100, the robot 100's movement speed is limited or its movement is stopped. Assuming the period of limiting the movement speed is very short, and the robot 100 resumes its normal movement, the robot 100 may have difficulty moving smoothly when restarting if the heater 320 is not continuously heating. Therefore, by making the circuits supplying power to each drive mechanism 40 of the robot 100 different from the circuits supplying power to each heater 320, heating of each drive mechanism 40 can continue even when power supply to each drive mechanism 40 is stopped. The circuit supplying power to the drive mechanism 40 is also referred to as the first circuit. The circuit supplying power to the heater 320 is also referred to as the second circuit.

[0075] B8. Other implementation methods 8

[0076] The temperature regulator 300 may further include a display panel that displays the temperature measured by the temperature sensor 310. This display panel is also referred to as a display unit. The temperature regulator 300 displays the temperatures measured in each drive mechanism 40 on the display panel. Since the temperature of each drive mechanism 40 can be visually confirmed, the user can easily monitor the temperature of each drive mechanism 40.

[0077] B9. Other implementation methods 9

[0078] In this embodiment, an example is described where the robot controller 500 sets the target temperature stored in the memory 521 to the temperature regulator 300. Alternatively, the robot controller 500 may set a temperature to the temperature regulator 300 that is a preset value higher than the target temperature stored in the memory 521. For example, the robot controller 500 may set a temperature of target temperature + 2°C to the temperature regulator 300. In this way, by setting the temperature set to the temperature regulator 300 slightly higher than the preset target temperature in advance, for example, ample temperature management can be provided to prevent a sharp drop in temperature in the environment where the robot 100 operates.

[0079] B10. Other implementation methods 10

[0080] Alternatively, the heating of the drive mechanism 40 can be performed as described below. For example, by using computer simulation, the heat dissipation per unit time of each drive mechanism 40 corresponding to the ambient temperature of the robot 100 is calculated in advance. At this time, the heat dissipation per unit time is calculated as if there were no workload of each drive mechanism 40 and no heat generation of the heater 320. In addition, a temperature sensor for measuring the ambient temperature of the robot 100 is placed near the robot 100. The heat generation of the heater 320 per unit time is controlled so that the heat dissipation per unit time of the drive mechanism 40 obtained from the ambient temperature measured by the temperature sensor for the ambient temperature is consistent with the sum of the heat generation per unit time of the drive mechanism 40 and the heat generation per unit time of the heater 320. It should be noted that the above control is performed on each drive mechanism 40.

[0081] B11. Other implementation methods 11

[0082] Furthermore, in the embodiment, an example in which a heater 320 is provided between the motor 42 and the reducer 44 of the drive mechanism 40 is described (see reference). Figure 3 , Figure 5 However, the number of heaters that heat a drive mechanism 40 can also be more than two. Figure 7 This is a diagram showing the installation location of the heater in another embodiment 11. (As shown) Figure 7 As shown, in arm element 24, the temperature sensor 310, heater 320a, and heater 320b of the drive mechanism 40 for driving joint J5 are disposed between motor 42 and reducer 44 and on the inner side of the bottom surface of body 31.

[0083] Alternatively, heaters 320 may be provided only for a portion of the six drive mechanisms 40. For example, since the heat generated by the motor 42 located at the front end of the arm 20 is less than that generated by the motor 42 located at the root end of the arm 20, heaters 320 may only be provided at the front end of the arm 20. Furthermore, since the heat generated is less when the motor 42 located at the root end of the arm 20 is not operated, heaters 320 may only be provided at the root end of the arm 20. Moreover, if the arm 20 is made of a material that easily conducts heat, heaters 320 may not be provided for adjacent arm elements, but only for the drive mechanisms 40 of arm elements 21, 23, and 25, and the drive mechanisms 40 of arm elements 22, 24, and 26. Additionally, if the angle sensor 49 is not a battery-free encoder, and the battery used to maintain the detection value is located in the drive mechanism 40 or outside the robot 100, the heater 320 may be located near the battery. This can suppress the decrease in battery capacity caused by low temperature.

[0084] In this embodiment, an example has been described where the body 31 of the arm element is a shell formed of aluminum or an aluminum alloy. However, the body 31 of the arm element may not be formed of the same material. For example, in... Figure 3 , Figure 5 In the main body 31 shown, only the bottom surface may be formed of aluminum or aluminum alloy, and the rest of the main body 31 may be formed of resin. In this case, a low-temperature resistant resin such as polycarbonate is preferred. By using a material with higher thermal conductivity than other parts to construct the bottom surface of the main body 31 where the heater 320 is disposed, the arm element can be heated efficiently. In addition, by using resin, the weight of the arm element can be reduced.

[0085] Furthermore, the shell constituting the main body 31 of the arm element is formed with a double-layered wall having an air layer or insulation material sandwiched between it. This prevents heat from the inside of the arm element from dissipating to the outside. For example, when the robot 100 is operating on a frozen food production line, it can prevent any impact on the temperature management of the production line.

[0086] Furthermore, when the robot 100 is moved from a room temperature environment to a low temperature environment, condensation is expected to occur inside the robot 100. Therefore, absorbent sponges can be placed near the substrate where the motor 42 and its encoder are installed, as well as near the substrate where various other sensors are installed. Alternatively, the air inside the arm element can be pre-extracted using a vacuum pump before moving the robot 100 from the room temperature environment to the low temperature environment. Alternatively, dry air can be supplied to the inside of the arm element using an air compressor before moving the robot 100 from the room temperature environment to the low temperature environment. Therefore, malfunctions due to condensation in the motor 42, encoder, and various sensors can be prevented.

[0087] Although an example of a six-axis vertical jointed robot is described in the implementation, robot 100 can also be a SCARA robot.

[0088] This disclosure is not limited to the embodiments described above, and can be implemented in various structures without departing from its spirit. For example, in order to solve some or all of the above-described technical problems, or to achieve some or all of the above-described effects, the technical features in the embodiments corresponding to the technical features in the aspects described in the summary section of the invention can be appropriately replaced or combined. Furthermore, if a technical feature is not described as an essential feature in this specification, it can be appropriately deleted.

[0089] C. Other aspects:

[0090] (1) According to one aspect of this disclosure, a robot system is provided. The robot system includes: a robotic arm; and a control unit for controlling the movement and temperature of the robotic arm. The robotic arm has: a first joint; a second joint, different from the first joint; a first drive unit for driving the first joint; and a second drive unit for driving the second joint, different from the first drive unit. The control unit includes: a first temperature measuring unit for measuring a first temperature of the first drive unit; a first heating unit for heating the first drive unit; a second temperature measuring unit for measuring a second temperature of the second drive unit, different from the first temperature measuring unit; a second heating unit for heating the second drive unit, different from the first heating unit; and an adjustment unit for controlling the heat output of the first heating unit to bring the first temperature of the first drive unit close to a preset first target value, and controlling the heat output of the second heating unit to bring the second temperature of the second drive unit close to a preset second target value.

[0091] Based on the above, since the heating of each drive unit is controlled based on the temperature of each individual drive unit, it is possible to heat each drive unit appropriately compared to heating all drive units uniformly. Therefore, the robotic arm can operate stably in low-temperature environments.

[0092] (2) In the robot system described above, the control unit may control the heat output of the first heating unit to maintain the first temperature of the first driving unit between a preset first lower limit and a preset first upper limit, and control the heat output of the second heating unit to maintain the second temperature of the second driving unit between a preset second lower limit and a preset second upper limit.

[0093] Based on the above aspects, since the heating element is controlled based on the temperature of each drive unit to maintain the temperature of each drive unit within the set range, each drive unit can operate stably.

[0094] (3) In the robot system described above, the control unit may control the first heating unit to generate heat with the heat output of the first heating unit per unit time, and control the second heating unit to generate heat with the heat output of the second heating unit per unit time. The heat output of the first heating unit per unit time is calculated based on the workload of the first driving unit calculated based on the action program, and the heat output of the second heating unit per unit time is calculated based on the workload of the second driving unit calculated based on the action program, which is used to make the robotic arm perform actions.

[0095] Based on the above aspects, each drive unit is heated with a heat output per unit time that is proportional to the heat output of each drive unit and corresponds to the workload in each drive unit. In this way, since each drive unit is heated with the required amount according to the workload of each drive unit, the drive units can be heated efficiently.

[0096] (4) In the robot system described above, the first drive unit may include a first motor and a first reducer, and the second drive unit may include a second motor and a second reducer. Alternatively, the first heating unit may be disposed between the position where the first motor is disposed and the position where the first reducer is disposed, and the second heating unit may be disposed between the position where the second motor is disposed and the position where the second reducer is disposed.

[0097] Based on the above, by arranging a heating element between the motor and the reducer, it is possible to heat both the motor and the reducer simultaneously using a single heating element.

[0098] (5) In the robot system described above, the first temperature measuring unit may also be configured to measure the temperature of a portion located at a predetermined first distance from the first motor between the position where the first motor is located and the position where the first reducer is located. The second temperature measuring unit may also be configured to measure the temperature of a portion located at a predetermined second distance from the second motor between the position where the second motor is located and the position where the second reducer is located.

[0099] By configuring each temperature measuring unit to be spaced apart from the motor included in the drive unit that is the object of measurement, it is possible to suppress the inclusion of error values ​​caused by the heat generated by the motor in the measured temperature of the drive unit.

[0100] (6) In the robot system described above, the first heating element may heat up by being supplied with current from a power source, and the second heating element may heat up by being supplied with current from the power source. Alternatively, the first heating element may have a first protection element that functions to cut off or limit the current from the power source based on a temperature rise, and the second heating element may have a second protection element that functions to cut off or limit the current from the power source based on a temperature rise.

[0101] Based on the above aspects, since the first heating unit and the second heating unit each have protective elements that cut off or limit the current from the power supply according to the temperature rise, it is possible to stop supplying current to the first heating unit and the second heating unit regardless of the control unit's operation. Therefore, it is possible to prevent the first drive unit and the second drive unit from overheating.

[0102] (7) In the robot system described above, if the control unit is instructed to stop the robotic arm while it is performing an action, it may also stop the heating of the first drive unit by the first heating unit and the heating of the second drive unit by the second heating unit.

[0103] Based on the above aspects, for example, when the robot is stopped in an emergency, stopping the heating can prevent unnecessary heating of the first drive unit and the second drive unit.

[0104] (8) In the robot system described above, a display unit for displaying the temperature may also be provided. The control unit may also cause the display unit to display the measured first temperature of the first drive unit and the second temperature of the second drive unit.

[0105] Based on the above aspects, since the temperatures of the first drive unit and the second drive unit can be visually confirmed separately, for example, a user can easily monitor the temperatures of the first drive unit and the second drive unit.

[0106] (9) In the robot system described above, the first line for supplying power from the power source to the first drive unit and the second drive unit may be different from the second line for supplying power from the power source to the first heating unit and the second heating unit.

[0107] Based on the above, since the power supply lines to each drive unit of the robotic arm and the power supply lines to each heating unit are independent lines, heating of each drive unit can continue even if the power supply to each drive unit is stopped, for example, in the event that the robot is stopped in an emergency.

[0108] (10) In the robot system described above, the first drive unit and the second drive unit may each have a battery-free encoder, and the robotic arm may operate in a low-temperature environment.

[0109] Based on the above, since each drive unit has a battery-free encoder that is not easily affected by low temperatures, it can operate even in low-temperature environments.

Claims

1. A robot system, characterized in that, have: robotic arms; and The control unit controls the movement and temperature of the robotic arm. The robotic arm has: The first arm has a first body, which is a hollow shell made of aluminum or aluminum alloy; The second arm has a second body, which is a hollow shell formed of aluminum or aluminum alloy and is different from the first arm; The first joint is connected to the first arm; The second joint is connected to the second arm and is different from the first joint; The first drive unit drives the first joint; as well as The second drive unit drives the second joint and is different from the first drive unit. The control unit has: A first temperature measuring unit is disposed on the first arm to measure the first temperature of the first arm; A first heating element is disposed on the first arm to heat the first arm; A second temperature measuring unit is disposed on the second arm to measure a second temperature of the second arm, and is different from the first temperature measuring unit. The second heating element is disposed on the second arm, heats the second arm, and is different from the first heating element; as well as The adjustment unit controls the heating of the first heating unit to bring the first temperature of the first arm close to a preset first target value, and controls the heating of the second heating unit to bring the second temperature of the second arm close to a preset second target value. The first driving unit includes: First motor; The first reducer drives the first joint; The first motor pulley is connected to the first motor; The first reducer pulley is connected to the first reducer; and The first belt is installed between the first motor pulley and the first reducer pulley. The position where the first motor is located is separate from the position where the first reducer is located. The first heating element is disposed near the location where the first motor is disposed and the location where the first reducer is disposed. The first heating element is disposed on the inner side of the first body.

2. The robot system according to claim 1, characterized in that, The control unit controls the heating of the first heating unit to maintain the first temperature of the first arm between a preset first lower limit and a preset first upper limit, and controls the heating of the second heating unit to maintain the second temperature of the second arm between a preset second lower limit and a preset second upper limit.

3. The robot system according to claim 1 or 2, characterized in that, The control unit controls the first heating unit to generate heat at the amount of heat generated per unit time, and controls the second heating unit to generate heat at the amount of heat generated per unit time. The amount of heat generated per unit time of the first heating unit is calculated based on the workload of the first driving unit calculated based on the action program, and the amount of heat generated per unit time of the second heating unit is calculated based on the workload of the second driving unit calculated based on the action program. The action program is used to make the robotic arm perform actions.

4. The robot system according to claim 1, characterized in that, The second drive unit includes: Second motor; The second reducer drives the second joint; The second motor pulley is connected to the second motor. The second reducer pulley is connected to the second reducer; and The second belt is installed between the second motor pulley and the second reducer pulley. The location where the second motor is located is separate from the location where the second reducer is located. The second heating element is disposed near the location where the second motor is disposed and the location where the second reducer is disposed. The second heating element is disposed on the inner side of the second main body.

5. The robot system according to claim 4, characterized in that, The first temperature measuring unit is configured to measure the temperature at a predetermined first distance separated from the first motor between the position where the first motor is located and the position where the first reducer is located. The second temperature measuring unit is configured to measure the temperature of a portion of the location separated from the second motor by a predetermined second distance between the location where the second motor is located and the location where the second reducer is located.

6. The robot system according to claim 1, characterized in that, The first heating element heats up by being supplied with current from a power source. The second heating element generates heat by being supplied with current from the power source. The first heating element has a first protection element that cuts off or limits the current from the power source based on a rise in temperature. The second heating element has a second protection element that cuts off or limits the current from the power source based on the temperature rise.

7. The robot system according to claim 1, characterized in that, When the control unit is instructed to stop the robotic arm while it is performing an action, it stops the heating of the first arm by the first heating unit and the heating of the second arm by the second heating unit.

8. The robot system according to claim 1, characterized in that, The robot system also has a display unit that shows the temperature. The control unit causes the display unit to display the measured first temperature of the first arm and the second temperature of the second arm.

9. The robot system according to claim 6, characterized in that, The first line for supplying power from the power source to the first drive unit and the second drive unit is different from the second line for supplying power from the power source to the first heating unit and the second heating unit.

10. The robot system according to claim 1, characterized in that, The first drive unit and the second drive unit each have a battery-free encoder. The robotic arm operates in a low-temperature environment.

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