Robotic system having a robot including a torque sensor

Abstract

A robot system includes a robot including a torque sensor corresponding to a joint axis. The robot system includes a sensor temperature determination unit that determines whether the temperature state of the torque sensor is an abnormal state or a suitable temperature state based on an output value of a temperature detection unit. The robot system includes an action command unit that reduces at least one of the speed and acceleration of a robot drive motor when a torque sensor has a temperature state that is neither an abnormal state nor a suitable temperature state.

Description

Technical Field

[0001] The present invention relates to a robot system having a robot including a torque sensor. Background Art

[0002] In recent years, collaborative robots designed to work in collaboration with humans have become commonplace. These collaborative robots, which rely on human-robot contact, employ torque sensors placed at the robot's joints to detect torque or external forces acting on the robot. These sensors measure the torque acting on the joints, or calculate the external forces acting on the robot based on the measured torque. Furthermore, these robots can detect human contact based on the torque or external forces acting on the robot, or implement direct teaching based on the torque or forces acting on the robot.

[0003] The torque sensor included in a robot experiences temperature fluctuations due to various factors, including temperature fluctuations caused by heat generated by the driver accompanying the robot's movement, temperature fluctuations in the robot's surrounding environment, and temperature fluctuations caused by heat generated by the torque sensor's internal circuitry. As a result, the torque data values ​​detected by the torque sensor may become inaccurate (see, for example, Japanese Patent Application Publication Nos. 2020-67295 and 2019-111597).

[0004] To address this problem, the torque sensor performs compensation by measuring the temperature of the portion where the displacement due to the applied torque is detected or its vicinity, and compensating the torque data based on the measured temperature (for example, see Japanese Patent Application Publication No. 2020-509342).

[0005] In addition, there is a known robot that stops the movement of the joint shaft equipped with the motor when the driving load of the robot joint shaft becomes too large, the motor of the robot joint shaft is in an overheated state, the ambient temperature of the motor is abnormal, or an abnormality is detected in the torque data detected by the torque sensor of the joint shaft (for example, refer to International Publication No. 2015 / 137038).

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2020-67295

[0009] Patent Document 2: Japanese Patent Application Publication No. 2019-111597

[0010] Patent Document 3: Japanese Patent Application No. 2020-509342

[0011] Patent Document 4: International Publication No. 2015 / 137038 Summary of the Invention

[0012] Problems to be solved by the invention

[0013] Robots equipped with internal torque sensors that measure the torque or force acting on them often have their internal airtightness enhanced to improve reliability, dustproofing, waterproofing, or to mitigate electrical noise. This can sometimes cause the temperature of the torque sensors on the robot's joint axes to reach high temperatures or experience rapid temperature fluctuations due to the robot's movements. Furthermore, to improve torque measurement accuracy, torque sensors are often mounted in close proximity to drive components such as motors and mechanical components such as reducers at the robot's joints to accurately transmit torque or force. As a result, heat from the robot's mechanical or drive components can easily transfer to the torque sensor.

[0014] Furthermore, the torque sensors on the robot's joint axes are susceptible to temperature fluctuations in the robot's operating environment, including the temperature of its arms and reducers, caused by temperature fluctuations in the surrounding environment, such as the robot's operating environment, peripheral devices, tools, the manipulator, or the objects being handled. Furthermore, the loads on the robot's joint axes can be small or large, depending on the robot's movements and the weight or center of gravity of the objects being handled. Depending on the load on the joint axes, the effect of temperature on the torque sensors can vary significantly.

[0015] Furthermore, depending on the robot's operating environment, the ambient temperature can range widely, from low to high. Furthermore, the temperature fluctuations associated with robot operation can range widely, sometimes occurring within a short period of time. The temperature of the torque sensors in the robot's joint axes can also fluctuate widely, from low to high temperatures, and can also fluctuate significantly within a short period of time.

[0016] Temperature compensation is required to address these changes in the torque sensor's temperature state. However, due to the configuration of the torque sensor's temperature sensor or the deterioration of the temperature sensor's accuracy, it is sometimes impossible to properly measure the torque sensor's temperature state. In addition, depending on the temperature state of the torque sensor, the approximate model of the torque sensor's temperature characteristics used in temperature compensation may not match the actual state, resulting in a larger error. Thus, depending on the temperature state of the torque sensor, such as when the torque sensor's temperature varies over a wide range, when the temperature changes significantly in a short period of time, or when the torque sensor's temperature state changes locally, the error in the temperature detection value may increase, or the accuracy of the temperature compensation itself may deteriorate. As a result, it may be difficult to properly temperature compensate the torque data, and the torque data value may become inappropriate.

[0017] Thus, depending on the temperature of the torque sensor, the output error of the torque sensor is large, and sometimes it is impossible to detect the appropriate torque. In addition, depending on the operation status of the robot or the status of the surrounding environment, the temperature of the torque sensor may be abnormal.

[0018] Furthermore, there are cases where the torque sensor's temperature condition is not abnormal, allowing continued use based on initial testing. However, this can undesirably result in a reduction in torque data detection accuracy. Furthermore, depending on the robot's operating method, even if appropriate temperature compensation based on torque data is performed, this can sometimes overload the robot's joints and accelerate failure.

[0019] Furthermore, when a worker is performing direct teaching or working collaboratively with a robot, they may need to directly contact the robot to stop it, change its movements, or modify its settings. In these situations, the temperature near the robot's joint axes or the temperature of the torque sensors on those joint axes is unknown. Consequently, the robot may reach unexpected temperatures, or the deterioration in the torque sensor's detection accuracy due to temperature fluctuations may be unknown.

[0020] For example, after driving a robot at high speed for an extended period in a non-coordinated motion mode, the robot's joints and torque sensors may reach high temperatures when used in a coordinated motion mode. Furthermore, even in a coordinated motion mode, prolonged high-load motion can cause the robot's joints and torque sensors to reach high temperatures. In such cases, even if there are no abnormalities in the torque sensor or the robot's actuators, the temperature can become too hot when touched by a human, degrading the temperature sensor's detection accuracy and reducing the torque sensor's detection accuracy.

[0021] Thus, even if the temperature of the robot's joints is sufficient for actuators such as motors, the torque sensor of the robot, which works in conjunction with a human operator, may not be at an appropriate temperature, degrading the torque sensor's detection accuracy. Alternatively, even if the torque sensor's detection accuracy is sufficient, it may overheat when the operator comes into contact with the robot, or it may be necessary to improve the torque sensor's detection accuracy.

[0022] Means for solving problems

[0023] One embodiment of the present disclosure is a robot system having a robot, the robot including a torque sensor corresponding to a joint axis. The robot system includes: a torque sensor including a torque detection unit and a temperature detection unit; and a temperature compensation unit that calculates temperature-compensated data based on output values ​​of the torque detection unit and the temperature detection unit. The robot system includes: a sensor temperature determination unit that determines whether the temperature state of the torque sensor is abnormal or in a suitable temperature state based on at least one output value of the temperature detection unit and the temperature compensation unit. The robot system includes: an action command unit that, when a torque sensor has an abnormal temperature state, changes the action command to stop the robot. When a torque sensor has a temperature state that is neither abnormal nor in a suitable temperature state, changes the action command to reduce at least one of the speed and acceleration of the joint axis on which the torque sensor is mounted.

[0024] Effects of the Invention

[0025] According to one aspect of the present disclosure, it is possible to provide a robot system that changes the robot operation according to the temperature state of the torque sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of a robot system in an embodiment.

[0027] Figure 2 This is a schematic diagram of a robot in the embodiment.

[0028] Figure 3 This is a block diagram of a first robot system in an embodiment.

[0029] Figure 4 This is a flowchart of control for changing the robot motion of the first robot system.

[0030] Figure 5 This is a flowchart of other controls for changing the robot motions of the first robot system.

[0031] Figure 6 2 is a block diagram of a second robot system in an embodiment.

[0032] Figure 7 This is a block diagram of a third robot system in the embodiment.

[0033] Figure 8 This is a schematic diagram of a robot including a first display unit according to an embodiment.

[0034] Figure 9 This is a schematic diagram of a robot having a second display unit according to an embodiment.

[0035] Figure 10 This is a schematic diagram of a robot including a third display unit in the embodiment.

[0036] Figure 11 This is a schematic diagram of a robot including a fourth display unit in the embodiment.

[0037] Figure 12 This is the first image displayed on the display unit in the embodiment.

[0038] Figure 13 This is the second image displayed on the display unit in the embodiment.

[0039] Figure 14 This is the third image displayed on the display unit in the embodiment.

[0040] Figure 15 This is the fourth image displayed on the display unit in the embodiment.

[0041] Figure 16 This is the fifth image displayed on the display unit in the embodiment.

[0042] Figure 17 This is the sixth image displayed on the display unit in the embodiment.

[0043] Figure 18 This is the seventh image displayed on the display unit in the embodiment.

[0044] Figure 19 This is the eighth image displayed on the display unit in the embodiment. DETAILED DESCRIPTION

[0045] Reference Figures 1 to 19 , the robot system in the embodiment is described. In the present invention, "prescribe" means to be determined before use or implementation. In addition, "prescribe" means to be predetermined before starting use or implementation, or to be determined before use or implementation, and to be determined at any timing until necessary. The prescribed variables, prescribed constants, or prescribed formulas, etc., can be appropriately determined based on the specifications of the robot system, the desired results, the status of the robot system, experimental results, or the acquired data. The robot system of this embodiment has a robot including a torque sensor, which is used to detect the torque applied to a structural component such as an arm. In the present invention, the speed or acceleration of the robot joint axis refers to the speed or acceleration of the movement of the robot joint axis consisting of a rotating axis or a linear axis.

[0046] (First Robot System)

[0047] Figure 1A schematic diagram showing the first robot system in the present embodiment. The first robot system 6 in the present embodiment has the function of transporting a workpiece 71. The first robot system 6 has: a manipulator 2 as a working tool (end effector), and a robot 1 that changes the position and posture of the manipulator 2. The robot system 6 has: a control device 4 that controls the robot 1 and the manipulator 2. The robot 1 in the present embodiment is a vertical multi-joint robot having 6 joint axes (rotation axes). In addition, in the present embodiment, the joint axes are composed of rotation axes, but are not limited to this method. In addition to the rotation axes, the joint axes may also be composed of direct-acting axes.

[0048] The robot 1 of this embodiment includes a base 14 fixed to a mounting surface and a swivel base 13 supported by the base 14. The swivel base 13 is configured to rotate relative to the base 14. The robot 1 includes an upper arm 11 and a lower arm 12. The lower arm 12 is rotatably supported on the swivel base 13 via a joint 17. The upper arm 11 is rotatably supported on the lower arm 12 via the joint 17. The upper arm 11 rotates about a rotation axis parallel to the direction in which the upper arm 11 extends.

[0049] The robot 1 includes a wrist 15 connected to the end of an upper arm 11. The wrist 15 is rotatably supported by the upper arm 11 via a joint 17. The wrist 15 includes a flange 16 that rotates about a rotation axis along the extending direction of the wrist 15. The manipulator 2 is fixed to the flange 16.

[0050] The robot 1 of this embodiment is a vertical multi-jointed robot having six joint axes, but is not limited to this configuration. Any robot that can change at least one of the position and posture of a working tool may be employed. For example, a robot having any number of joint axes may be employed.

[0051] The robot arm 2 of this embodiment grips and releases a workpiece 71. The robot arm 2 grips the workpiece 71 by closing its opposing claws. The work tool is not limited to a robot arm that grips a workpiece. Any work tool can be attached to the robot system depending on the task it performs. For example, when the robot system performs arc welding, a welding torch can be attached to the robot.

[0052] Figure 2 A schematic diagram showing a robot according to this embodiment. Figure 1 as well as Figure 2The robot 1 includes joint shafts 17a, which serve as rotational axes for components such as arms. The robot 1 is configured to have multiple joint shafts 17a. As indicated by arrow 91, a torque sensor 20 is disposed on each joint 17 to detect torque around the joint shaft 17a. The robot 1 of this embodiment includes two or more joint shafts 17a equipped with torque sensors 20. That is, torque sensors 20 are disposed on two or more of the six joint shafts 17a of the robot 1.

[0053] In this embodiment, a torque sensor 20 is attached to each of the six joint axes of the robot 1. That is, while the robot 1 in this embodiment is equipped with six torque sensors 20, this is not limiting. A torque sensor may also be attached to the joint axis that requires the least torque detection.

[0054] Furthermore, as described later, the temperature status of the torque sensor can be determined by comparing the output value of the temperature detection unit included in the torque sensor configured on one joint axis with the output value of the temperature detection unit included in the torque sensor configured on another joint axis. However, if this determination is not performed, a torque sensor may be configured on one or more joint axes of the robot. Furthermore, a force sensor capable of detecting moment (force or torque), or a load cell capable of detecting force, may be installed on a joint axis not equipped with a torque sensor.

[0055] Figure 3 A block diagram showing a robot system in this embodiment. Figures 1 to 3 , the robot 1 includes: a robot driving unit that changes the position and posture of the robot 1. The robot driving unit includes: a robot driving motor 19 that is an electric motor that drives structural components such as an arm. The robot driving unit drives the actuators arranged on the joint shafts to move the rotational positions of the various joint shafts 17a of the robot 1. In addition, the robot driving unit can be composed of any principle or power as long as it can drive the joint shafts of the robot to cause them to displace. In addition, when the joint shaft is a linear shaft, the robot driving unit drives the actuators arranged on the joint shafts to move the position on the linear shaft. The manipulator 2 has a manipulator driving unit that drives the manipulator 2. The manipulator driving unit includes a pressure pump and a valve, etc. for driving the claws of the manipulator 2.

[0056] The robot system 6 includes a control device 4 that controls the robot 1 and manipulator 2. The control device 4 includes a processing unit (computer) with a CPU (Central Processing Unit) as a processor. The processing unit includes RAM (Random Access Memory) and ROM (Read Only Memory) connected to the CPU via a bus. An operating program 41 includes operating instructions (command statements) for driving the robot 1 and manipulator 2. The robot system 6 is driven according to the operating program 41 to transport a workpiece.

[0057] The control device 4 includes a storage unit 42 for storing information. The storage unit 42 stores information related to the control of the robot 1 and the manipulator 2. The operation program 41 is stored in the storage unit 42. The storage unit 42 can be composed of a non-transitory storage medium. For example, the storage unit 42 can be composed of a storage medium capable of storing information, such as a volatile memory, a non-volatile memory, a magnetic storage medium, or an optical storage medium.

[0058] The control device 4 includes a motion command unit 43 that issues motion commands. The motion command unit 43 corresponds to a processor that is driven according to the motion program 41. The motion command unit 43 is configured to read information stored in the storage unit 42. The processor reads the motion program 41 and implements the control specified in the motion program 41, thereby functioning as the motion command unit 43. The robot drive unit is driven according to the motion commands output by the motion command unit 43, changing the rotational position of the robot drive motor 19 on the joint axis of the robot 1.

[0059] The motion command unit 43 sends motion commands for driving the robot 1 to the robot drive circuit 45. The robot drive circuit 45 includes circuitry for driving the robot drive motor 19. The robot drive circuit 45 supplies power to the robot drive motor 19 in response to the motion commands. Furthermore, the motion command unit 43 sends motion commands for driving the manipulator 2 to the manipulator drive circuit 44. The manipulator drive circuit 44 includes circuitry for driving the manipulator drive unit. The manipulator drive circuit 44 supplies power to the manipulator drive unit in response to the motion commands.

[0060] The robot 1 includes a rotational position detector 18 that outputs the rotational position of the joint axis 17a of the robot 1, i.e., axis position data. The rotational position detector 18 is configured, for example, as an encoder. The output of the rotational position detector 18 enables detection of the position and posture of the robot 1. In this embodiment, the rotational position detector 18 is attached to the robot drive motor 19, which is arranged corresponding to each joint axis. The rotational position detector 18 is configured to detect the rotation angle or phase when the robot drive motor 19 is driven.

[0061] The control device 4 of this embodiment includes an action control unit 31 that transmits information regarding action changes to the action command unit 43 based on the output from the torque sensor 20. The action control unit 31 includes a conversion unit 32 that converts the output of the displacement detector 21 of the torque sensor 20 into torque data. The action control unit 31 also includes a temperature compensation unit 33 that performs temperature compensation on torque-related values. Furthermore, the action control unit 31 includes a sensor temperature determination unit 34 that determines the temperature status of the torque sensor 20.

[0062] The motion control unit 31 corresponds to a processor driven according to the motion program 41. The motion control unit 31 is configured to read information stored in the storage unit 42. The processor reads the motion program 41 and implements the control specified in the motion program 41, thereby functioning as the motion control unit 31. Furthermore, the conversion unit 32, temperature compensation unit 33, and sensor temperature determination unit 34 included in the motion control unit 31 each correspond to a processor driven according to the motion program 41. The processor implements the control specified in the motion program 41, thereby functioning as each unit.

[0063] (Torque sensor)

[0064] The torque sensor 20 of this embodiment is a sensor configured on the joint shaft 17a of the robot 1. The torque sensor 20 detects, as torque, the moment of force generated by a force acting on the component to which the torque sensor 20 is mounted. The torque sensor 20 of this embodiment includes a torque detection unit 23 that detects a value related to torque, and a temperature detection unit 24 that detects a value related to temperature. The torque detection unit 23 includes one or more displacement detectors 21 that detect a value based on the torque acting on the joint shaft 17a of the robot 1. The temperature detection unit 24 includes one or more temperature sensors 22 that detect the temperature of the torque sensor 20. In the robot system 6 of this embodiment, the torque acting on the torque sensor 20 configured on the joint shaft 17a of the robot 1 is detected or measured, and the temperature of the torque sensor 20 is detected or measured. In this embodiment, detecting torque or temperature includes measuring torque or temperature.

[0065] The displacement detector 21 detects relative displacement of components constituting the torque sensor 20 at one or more predetermined locations of the torque sensor 20. The value related to the torque detected by the torque sensor 20 (torque-related data) includes torque data including the torque value and a value based on the torque.

[0066] The torque-based value is, for example, a value obtained by calculating the torque data by multiplying the output value of the displacement detector 21 by a predetermined calculation formula such as calibration data. For example, when the torque sensor is a strain gauge type composed of a Wheatstone bridge circuit, the value obtained by converting the displacement of the strain gauge into a voltage corresponds to the torque-based value. Figure 3 The torque sensor 20 shown in FIG. 1 outputs the output value of the displacement detector 21 as a value based on the torque. The conversion unit 32 of the motion control unit 31 of the control device 4 calculates the torque data using the output values ​​of the plurality of displacement detectors 21 and calibration data that associates the output values ​​of the displacement detectors 21 with the values ​​of the torque data.

[0067] The temperature compensating unit 33 performs temperature compensation on the value related to the torque. Figure 3 The temperature compensating unit 33 shown performs temperature compensation on the torque data output from the converter 32. The temperature sensor 22 of the temperature detecting unit 24 is configured to detect the temperature of one or more predetermined portions of the torque sensor. The temperature compensating unit 33 compensates the torque data based on the temperatures obtained from the one or more temperature sensors 22 and a reference temperature for temperature compensation.

[0068] Alternatively, torque data can be calculated after temperature compensation has been performed on the torque-based value. Specifically, the temperature compensator 33 can calculate the temperature-compensated torque value based on the torque value detected by the torque detector 23, the temperature data of the torque sensor 20 output by the temperature detector 24, and the reference temperature used for temperature compensation. The converter 32 can then calculate torque data including the torque based on the temperature-compensated torque value and the calibration data. In this manner, either the conversion from the torque-based value to the torque data or the temperature compensation can be performed first.

[0069] Furthermore, at least one of the conversion unit 32 and the temperature compensation unit 33 may be disposed in the torque sensor 20 instead of the motion control unit 31 of the control device 4. The torque sensor 20 may include a processing unit including a processor. The processor of the torque sensor may then function as both the conversion unit and the temperature compensation unit.

[0070] For example, when the torque detection unit 23 of the torque sensor 20 includes the conversion unit 32, the torque detection unit 23 can calculate torque data using the output values ​​of the plurality of displacement detectors 21 and calibration data that associates the output values ​​of the displacement detectors 21 with the values ​​of the torque data. The torque data is transmitted from the torque sensor 20 to the motion control unit 31.

[0071] Furthermore, when the torque sensor 20 includes the temperature compensating unit 33, the torque sensor 20 can perform temperature compensation on the value of the torque output from the displacement detector 21 based on the temperature obtained from the temperature sensor 22 and a reference temperature related to temperature compensation. The value of the torque based on the temperature-compensated torque is transmitted from the torque sensor 20 to the motion control unit 31.

[0072] When the torque sensor 20 includes the conversion unit 32 and the temperature compensation unit 33 , the torque sensor 20 can convert the value based on torque into torque data and perform temperature compensation. The torque sensor 20 then transmits the temperature-compensated torque data to the operation control unit 31 .

[0073] Furthermore, at least one of the conversion unit 32 and the temperature compensation unit 33 may be disposed in a device separate from the control device 4 and the torque sensor 20. For example, at least one of the conversion unit 32 and the temperature compensation unit 33 may be disposed in a processing unit separate from the control device. In this manner, at least one of the conversion from the torque-based value to the torque data and the temperature compensation may be performed in a separate processing unit having a processor.

[0074] Furthermore, the temperature compensating unit 33 may also function as the converting unit 32. Specifically, the temperature compensating unit may simultaneously convert the torque value detected by the displacement detector, the calibration data used for conversion to torque data, the temperature data output by the temperature detecting unit, and the reference temperature for temperature compensation. In this case, the temperature compensating unit may calculate temperature-compensated torque data based on the output value of the displacement detector.

[0075] The reference temperature used as a reference when performing temperature compensation of torque-related values ​​is preferably the temperature used when calibrating the torque sensor or a temperature close thereto. For example, approximately 25° C., which is room temperature, can be used as the reference temperature.

[0076] The temperature detection unit 24, which includes the temperature sensor 22, outputs representative temperature data of the torque sensor 20, temperature data at various locations of the components constituting the torque sensor, or values ​​based on these temperatures. The temperature-based value is a value that replaces the temperature data or can be converted to temperature data. For example, the temperature-based value can be used in place of the temperature data, can be converted to temperature data using a predetermined calculation formula, can be converted to a value that facilitates data transmission, or can change depending on the temperature.

[0077] The temperature sensor 22 is preferably placed at a location convenient for detecting the temperature of the torque sensor 20 or for performing temperature compensation. The temperature sensor 22 may also be placed at or near the location where the displacement detectors 21 are placed.

[0078] The torque sensor in this embodiment detects torque about a single rotational axis, but is not limited to this embodiment. The torque sensor may also include a force detection unit capable of detecting force. Any torque sensor can detect torque acting about a joint axis. For example, the torque sensor may be a force sensor capable of detecting force and torque components along three or six axes.

[0079] Torque and force can be detected using a detector that detects a physical quantity that changes with the relative displacement of the sensor's components. In this case, the detection unit can be configured so that the change in relative displacement of the components is a change in charge, inductance, light, ultrasound, or magnetism that changes with the relative displacement. Alternatively, an optical sensor can be configured to detect the positional changes of corresponding points on an image or image information that changes with the relative displacement of the components to detect torque and force. In this case, the physical quantity that changes with the relative displacement of the sensor's components corresponds to a value based on the torque.

[0080] For example, the displacement detector may be configured as a Wheatstone bridge circuit comprised of strain gauges to convert the relative displacement of components constituting the torque sensor into a voltage and output it. In this case, the displacement detector may output the displacement of the strain gauge as a voltage. Alternatively, the displacement detector may be configured to output the displacement of an electrostatic capacitor as a voltage.

[0081] Furthermore, in the torque detection method of the torque detection unit 23 of this embodiment, the displacement detector 21 detects the relative displacement of the structural components constituting the torque sensor. The detected relative displacement is then converted into torque, but this method is not limited to this. The torque sensor may use any detection method as long as it can detect torque.

[0082] The temperature sensor 22 of the temperature detection unit 24 is configured using an element such as a thermistor, thermocouple, or platinum resistor. It detects changes in resistance or electromotive force due to changes in physical properties caused by temperature and converts these changes into temperature data. Alternatively, the torque sensor may include two or more temperature sensors, and the outputs of multiple temperature sensors may be used to detect the temperature of the torque sensor.

[0083] The temperature detection unit 24 outputs the detection value of the temperature sensor 22 or a value obtained based on the value detected by the temperature sensor 22. Furthermore, when there are two or more temperature sensors, the temperature detection unit may output the detection values ​​of the plurality of temperature sensors. Alternatively, the temperature detection unit may include a processing unit including a processor and output one or more values ​​obtained based on the values ​​detected by the plurality of temperature sensors.

[0084] For example, when the torque sensor is equipped with multiple temperature sensors, the temperature detection unit may calculate and output a value by averaging the outputs of the multiple temperature sensors. Alternatively, the temperature detection unit may weight the outputs of the temperature sensors according to their positions, average them, and calculate and output a single representative value. Alternatively, the outputs of the multiple temperature sensors may be weighted to select and output a single representative value. For example, the median value among the outputs of the multiple temperature sensors may be selected.

[0085] Alternatively, the temperature detection unit may calculate a representative value for a plurality of temperature sensors disposed near the displacement detector by combining their outputs into a single set. This value may then be used as temperature data near the displacement detector in the temperature compensation unit and the sensor temperature determination unit.

[0086] Alternatively, the temperature detection unit of the torque sensor may be equipped with two or more temperature sensors whose detection accuracy varies depending on the temperature. The outputs of the temperature sensors can then be selected so that the temperature detection accuracy remains high even when the temperature of the torque sensor fluctuates. In this case, it is preferred that at least two of the temperature sensors have temperature characteristics such that the detection accuracy varies depending on the temperature, and the temperature ranges within which the temperature detection accuracy exceeds a predetermined threshold are different.

[0087] The temperature detection unit can estimate a range within which the temperature of a predetermined portion of the torque sensor exists based on the outputs of two or more temperature sensors included in the torque sensor. The temperature detection unit can output a temperature detection value of the predetermined portion of the torque sensor based on the estimated temperature range and the outputs of the temperature sensors. For example, the temperature detection unit can estimate a predetermined range including a median value among the outputs of multiple temperature sensors as the range within which the temperature of the predetermined portion exists. The output of one of the multiple temperature sensors that falls within the predetermined range can then be selected. For example, the median value within the predetermined range can be selected.

[0088] Alternatively, the outputs of two or more temperature sensors included in the torque sensor can be used to estimate the temperature range of a predetermined portion of the torque sensor and assign weights to the outputs of the multiple temperature sensors. For example, the outputs of each temperature sensor can be multiplied by a weighting coefficient to calculate an average. In this case, the temperature detection unit can change the weighting of the temperature sensor outputs based on the estimated temperature range of the torque sensor. The temperature detection unit can output the calculated value as the temperature value of the predetermined portion of the torque sensor. In this case, the weight or coefficient of the output of the temperature sensor with excellent detection accuracy within the temperature range can be set relatively large.

[0089] Furthermore, the temperature compensation unit or the sensor temperature determination unit may perform calculations based on the detection values ​​of multiple temperature sensors in the temperature detection unit. Specifically, when there are two or more temperature sensors, the temperature detection unit outputs the detection values ​​of the multiple temperature sensors. The temperature compensation unit or the sensor temperature determination unit may then perform calculations related to the temperature of a predetermined portion of the torque sensor based on the values ​​detected by the multiple temperature sensors.

[0090] Furthermore, it is preferable to arrange temperature sensors with different temperature characteristics depending on the position of the displacement detector that detects the relative displacement of the components constituting the torque sensor. Alternatively, multiple temperature sensors with different temperature characteristics at different locations on the torque sensor may be installed near the same location. Alternatively, temperature sensors with different temperature characteristics may be arranged at different locations on the torque sensor.

[0091] (Temperature compensation unit)

[0092] Next, refer to Figure 3 Next, the temperature compensation unit 33, which performs temperature compensation for torque-related values, will be described. The temperature compensation unit 33 compensates torque data or torque-based values ​​based on temperature. Here, torque data including torque values ​​will be used as an example of torque-related values. Temperature compensation can also be performed on torque-based values ​​using the same method as for torque data.

[0093] The temperature compensation unit 33 performs temperature compensation on the torque data using a predetermined temperature compensation equation. The temperature compensation unit 33 can calculate a value related to the temperature-corrected torque using the predetermined temperature compensation equation, regardless of the method used to temperature-compensate the torque data or the method used to temperature-compensate the torque value.

[0094] When obtaining the torque data after temperature compensation, the temperature used as the reference, i.e., the reference temperature in the temperature compensation, can be predetermined. The reference temperature is preferably the temperature at which the torque sensor is calibrated or a temperature close to the temperature. In addition, the reference temperature may be a temperature corresponding to the type of torque sensor, the temperature of the location where the robot is installed, or a temperature corresponding to the temperature state of the joint of the robot having the torque sensor. Alternatively, the reference temperature may be a plurality of temperatures when calibration is performed at a plurality of temperatures, taking into account the temperature of the torque sensor, etc. The reference temperature may also be a temperature corresponding to the torque sensor, or a temperature taking into account the temperature state of the torque sensor. In addition, the calibration data used when obtaining the reference temperature or torque data may be changed according to the temperature conditions.

[0095] Furthermore, when temperature compensation is performed by the temperature compensating unit, the temperature detecting unit may measure and output the temperature of the portion of the torque sensor where the displacement detectors are located. The temperature compensating unit may also calculate temperature-compensated torque data based on the temperature of the portion where the multiple displacement detectors are located, a reference temperature for temperature compensation, the output values ​​of the multiple displacement detectors, and calibration data. Alternatively, the temperature-compensated torque data may be calculated based on the output values ​​of the multiple displacement detectors, a representative temperature value in the torque sensor, a coefficient related to temperature compensation, and calibration data. Alternatively, the temperature-compensated torque data may be calculated by multiplying the output values ​​of the multiple displacement detectors by calibration data that takes temperature compensation into account.

[0096] In the temperature compensation unit 33, the temperature compensation calculation formula used when implementing temperature compensation of the value related to the torque can be any formula as long as the value related to the torque after temperature compensation can be calculated based on the output value of the torque detection unit, the output value of the temperature detection unit, and the reference temperature in the temperature compensation.

[0097] First, an example will be described in which the value of the displacement detector 21 (value based on torque) output from the torque detector 23 is temperature compensated. The output value of the displacement detector after temperature compensation can be calculated from the output value of each displacement detector 21 as shown in the following equation (1).

[0098] Pb=(1+α1×(Tc-Tr)+α2×(Tc 2 -Tr 2 ))×(Pa+α3×(Tc-Tr)+α4×(Tc 2 -Tr 2 ))… (1)

[0100] Pa: Output value of the displacement detector before temperature compensation

[0101] Pb: Output value of displacement detector after temperature compensation

[0102] Tc: current temperature

[0103] Tr: reference temperature

[0104] α1, α2, α3, α4: coefficients

[0105] Temperature-compensated torque data is obtained by multiplying the output values ​​of each displacement detector, which has been temperature-compensated, by the calibration data. To appropriately temperature-compensate the output values ​​of the displacement detectors 21, it is preferable to use a temperature compensation equation that corresponds to the temperature characteristics of each displacement detector. The coefficients and constant terms of the equation are preferably precalculated based on a plurality of data points. The equation is preferably determined so that the temperature-compensated value can be appropriately calculated when given varying current temperature data.

[0106] Next, an example will be described in which temperature compensation is performed on torque data obtained by multiplying the output value of each displacement detector 21 by calibration data. The torque data after temperature compensation can be calculated as shown in the following equation (2).

[0107] TRb=(1+α1×(Tc-Tr)+α2×(Tc 2 -Tr 2 ))×(TRa+α3×(Tc-Tr)+α4×(Tc 2 -Tr 2 ))… (2)

[0109] TRa: Torque data before temperature compensation

[0110] TRb: Torque data after temperature compensation

[0111] Tc: current temperature

[0112] Tr: reference temperature

[0113] α1, α2, α3, α4: coefficients

[0114] When compensating torque data, in order to appropriately temperature-compensate the torque data output value, it is preferable to use a temperature compensation equation corresponding to the temperature characteristics of the torque data detected by the output of the torque sensor. The coefficients and constant term of the equation are preferably determined to be accurate values ​​after compensation based on the reference temperature and the current temperature.

[0115] This embodiment of temperature compensation involves compensation for displacements other than those caused by external forces, based on temperature changes in the output of the displacement detector. The coefficients and constants of this equation can be set using various methods. For example, a data set of theoretical and measured displacement detector output values ​​can be generated at multiple temperatures. Based on this data set, the coefficients and constants of the equation can be calculated to minimize the error between the calculated value and the measured value.

[0116] Here, the value related to temperature compensation in this embodiment can be the difference between the current temperature and the reference temperature used in temperature compensation, or the coefficient or constant term used in the temperature compensation equation at the temperature being compensated, or a value obtained midway through the temperature compensation calculation process. Furthermore, the value related to temperature compensation can be the difference or ratio of the coefficient or constant term used in the temperature compensation equation, or the value obtained midway through the temperature compensation calculation process due to temperature compensation. The value related to temperature compensation can be the difference or ratio between the output value of each displacement detector that has undergone temperature compensation and the output value of each displacement detector that has not undergone temperature compensation, or the difference or ratio between torque data that has undergone temperature compensation and torque data that has not undergone temperature compensation. The value related to temperature compensation is a value related to the coefficient or output value used in temperature compensation, and can be any value as long as it can confirm the effect or influence of temperature compensation.

[0117] Furthermore, a temperature compensation unit can be disposed within the torque sensor, with each torque sensor outputting temperature-compensated torque data and temperature data. Furthermore, when the torque sensor includes a temperature compensation unit, a sensor temperature determination unit can be disposed within each torque sensor. In other words, the torque sensor can output a determination result of the torque sensor temperature.

[0118] Alternatively, the temperature compensation unit can be configured within a control device or robot drive unit, integrated within or external to the robot, or within a device within the robot system. In this case, the output of each torque sensor can be input to the control device, etc., and the temperature compensation unit within the control device, etc., performs temperature compensation on the torque-related values ​​based on the temperature data output by each torque sensor and the torque-related values. Furthermore, when the temperature compensation unit is incorporated into the control device, etc., a sensor temperature determination unit can be further included to output the results of the determination of the temperature status of the torque sensors.

[0119] (Sensor temperature determination unit)

[0120] The sensor temperature determination unit 34 determines whether the temperature of the torque sensors 20 disposed on the joint shafts 17a of the robot 1 is abnormal. If the temperature of each torque sensor 20 is not abnormal, the sensor temperature determination unit 34 determines whether the torque sensor 20 is in a suitable temperature state. For example, a temperature of approximately 80°C or higher can be used as the temperature indicating an abnormal state of the torque sensor 20. For example, a temperature of approximately 40°C or lower can be used as the temperature indicating a suitable temperature state of the torque sensor.

[0121] Determining the temperature status of each torque sensor involves determining whether the torque acting on the torque sensor is abnormal or, while not abnormal, is in an appropriate state. Furthermore, determining the temperature status involves determining whether the torque sensor's temperature is abnormal or, while not abnormal, in an appropriate state when a worker is in contact with a joint shaft equipped with the torque sensor. The purpose of determining the temperature status is to determine whether the torque sensor has reached a state related to the torque sensor temperature described below.

[0122] The determination of the temperature condition is based on whether the torque data detected by the torque sensor differs from the actual torque value acting on the torque sensor due to the temperature condition of the torque sensor, or whether the degree of difference is within an allowable range. Furthermore, the determination is based on whether the output of the temperature detection unit that detects the temperature of the torque sensor differs from the value indicating the actual temperature condition of the torque sensor, or whether the degree of difference is within an allowable range. Furthermore, the determination is based on whether the condition related to the temperature of the torque sensor is such that an accurate value cannot be calculated when calculating temperature-compensated torque data, or whether the difference from the accurate value is large.

[0123] In addition, it is determined whether the state related to the temperature of the torque sensor is likely to become a state in which the correct value cannot be calculated when calculating the torque data after temperature compensation, or whether it can be predicted. In addition, it is determined whether the state in which the difference from the correct value becomes larger is likely to become a state in which it can be predicted. For example, it is determined whether the change value (amount of change) of the temperature state of the torque sensor is large, or whether the temperature state of the torque sensor is heading towards a deteriorating state, or whether the difference in temperature measured at multiple locations inside the torque sensor is large, or whether it becomes uneven. In addition, based on the temperature state of the torque sensor possessed by the joint axis of the robot, it is determined whether the temperature of the joint part of the robot becomes hotter when touched by the operator, whether the temperature of the joint part greatly varies depending on the location of the joint axis of the robot, etc.

[0124] The sensor temperature determination unit 34 determines whether the robot's operation needs to be modified by evaluating the torque sensor's temperature. If the robot's operation needs to be modified, the sensor temperature determination unit 34 can modify the robot's operation or notify the operator of the status.

[0125] The sensor temperature determination unit 34 determines, for each torque sensor 20, whether the temperature state of the torque sensor is abnormal based on at least one of the output value of the temperature detection unit 24 of the torque sensor 20 and the value related to the temperature compensation of the torque data performed by the temperature compensation unit 33, using predetermined determination conditions. If the temperature state of the torque sensor is not abnormal, the sensor temperature determination unit 34 determines whether the temperature state of the torque sensor is at a suitable temperature based on other predetermined determination conditions. Alternatively, the sensor temperature determination unit 34 may compare at least one of the output value of the temperature detection unit of the torque sensor and the value related to the temperature compensation of the torque data performed by the temperature compensation unit with values ​​of other torque sensors to determine whether the temperature state of the torque sensor is abnormal or whether the temperature state of the torque sensor is at a suitable temperature.

[0126] Here, the value based on the output value of the temperature detection unit of the torque sensor represents a value calculated using a temporal variation value or a value calculated based on the value measured at each position of the output of the temperature detection unit or each temperature sensor disposed in the temperature detection unit. The value based on the output value of the temperature detection unit includes the output value of the temperature detection unit, the time differential value of the output value of the temperature detection unit, and the temporal variation value (amount of variation) within a predetermined time period. The value based on the output value of the temperature detection unit includes the output value corresponding to the measurement position of the temperature sensor constituting the temperature detection unit. If there are multiple temperature sensors constituting the temperature detection unit, the value based on the output value of the temperature detection unit includes the difference between one temperature sensor and the other temperature sensors, the time differential value of the difference with the other temperature sensors, and the temporal variation value of the difference with the other temperature sensors within a predetermined time period. Furthermore, the value based on the output value of the temperature detection unit includes the time differential value of the temperature sensor constituting the temperature detection unit and the temporal variation value within a predetermined time period.

[0127] Furthermore, the values ​​related to the temperature compensation of the torque data performed by the temperature compensation unit are values ​​associated with the calculation of the torque data after temperature compensation. The values ​​related to temperature compensation are values ​​calculated based on the results of temperature compensation or values ​​that change due to temperature compensation during the temperature compensation calculation process. For example, the values ​​related to temperature compensation include: the difference or ratio between the pre-temperature compensated and post-temperature compensated values ​​of the torque data; the difference or ratio between the pre-temperature compensated and post-temperature compensated coefficients or constant terms in the temperature compensation calculation formula; the difference or ratio between the pre-temperature compensated and post-temperature compensated values ​​of the values ​​detected by the displacement detector; and values ​​calculated based on the pre-temperature compensated and post-temperature compensated values ​​in the calibration data.

[0128] Here, regarding the coefficients or constant terms in the temperature compensation equation, examples of the coefficients or constant terms before temperature compensation and the coefficients or constant terms after temperature compensation are described. In the above equation (1), if the term (Tc-Tr) is set to a constant T1, (Tc 2 -Tr 2 ) is set as a constant T2, then the formula (1) is transformed into the following formula (3).

[0129] Pb=(1+α1×T1+α2×T2)×(Pa+α3×T1+α4×T2)…(3)

[0130] Furthermore, if the term (1+α1×T1+α2×T2) is represented by the constant γ1, the term (α3×T1+α4×T2) is represented by the constant γ2, and (γ1×γ2) is represented by the constant γ3, then equation (3) is represented by the following equation (4).

[0131] Pb=γ1×Pa+γ3…(4)

[0132] According to formula (4), the output value Pb of the displacement detector after temperature compensation can be expressed as (γ1×Pa+γ3) relative to the output value Pa of the displacement detector before temperature compensation. In the calculation formula of formula (4), the coefficient of the calculation formula at the temperature after temperature compensation is γ1, and the constant term at the temperature after temperature compensation is γ3. In contrast, the output value of the displacement detector before temperature compensation is Pa, so the coefficient of the calculation formula at the temperature before temperature compensation is 1, and the constant term at the temperature before temperature compensation is 0. Using these coefficients or constant terms, the difference or ratio between the coefficients of the calculation formula at the temperature before temperature compensation and the coefficients of the calculation formula at the temperature after temperature compensation can be calculated. Alternatively, the difference or ratio between the constant term of the calculation formula at the temperature before temperature compensation and the constant term of the calculation formula at the temperature after temperature compensation can be calculated.

[0133] As coefficients or constants in the temperature compensation equation, the aforementioned γ1, γ2, and γ3 can be used. Alternatively, (α1×T1), (α2×T2), (α3×T1), and (α4×T2) can be used.

[0134] Next, the predetermined determination condition may be a condition for determining the temperature state of the torque sensor based on a value that changes according to a predetermined temperature state of the torque sensor. The predetermined determination condition includes comparing a value used for determination with a predetermined threshold value, or comparing a value calculated for determination with a predetermined threshold value. Predetermined determination conditions also include determining whether multiple conditions are satisfied, or comparing a score calculated by weighting each of the multiple conditions with a predetermined threshold value.

[0135] The threshold value in the determination condition used for determining whether the torque sensor's temperature state is in an abnormal state may be set to a different value than the threshold value in the determination condition used for determining whether the torque sensor's temperature state is in an appropriate temperature state. Alternatively, not only the threshold value in the determination condition, but also values ​​related to the torque sensor's temperature state used in the determination condition, the determination method, the comparison threshold value, or the coefficient may be set to different values.

[0136] To determine whether the temperature state of the torque sensor is abnormal, the output value of a temperature detection unit of the torque sensor, a change in the output value of the temperature detection unit within a predetermined time, or a value related to temperature compensation of torque data performed by a temperature compensation unit may be used. To determine whether the temperature state of the torque sensor is at a suitable temperature, the output value of the temperature detection unit of the torque sensor, or the output value of the temperature detection unit and the change in the output value of the temperature detection unit within a predetermined time may be used.

[0137] The sensor temperature determination unit can use the determination criteria and determination value corresponding to the joint axis portion containing the torque sensor to determine whether the torque sensor's temperature status is abnormal. For example, depending on the joint axis portion containing the torque sensor, there may be situations where the torque sensor specifications or performance differ, the load or frequency of use on the joint portion differs, the frequency of contact with the operator or surrounding objects differs, the risk of contact with the operator or surrounding objects differs, or the temperature conditions permitted by the operator or surrounding objects differ. Thus, when the determination criteria for the temperature status of each torque sensor differ, it is possible to determine whether the torque sensor's temperature status is abnormal based on the joint axis portion containing the torque sensor.

[0138] Similar to this control, the sensor temperature determination unit can use the determination criteria and determination value corresponding to the joint shaft portion having the torque sensor to determine whether the torque sensor's temperature is within the appropriate temperature state. This control allows determination of whether the torque sensor's temperature is within the appropriate temperature state based on the joint shaft portion having the torque sensor, even when the determination criteria for the torque sensor's temperature state differ.

[0139] The sensor temperature determination unit determines whether the temperature of the torque sensor is abnormal using abnormality determination conditions for determining an abnormality in the torque sensor. These abnormality determination conditions include: comparing the output value of the temperature detection unit of the torque sensor with a predetermined threshold; comparing the output value of the temperature detection unit within a predetermined time period with a predetermined threshold; comparing the compensation value of torque data temperature-compensated by the temperature compensation unit with a predetermined threshold; and comparing the output value of the temperature detection unit of a torque sensor of one joint axis with the output values ​​of the temperature detection units of torque sensors of other joint axes. The abnormality determination conditions may be composed of at least one of these determination conditions and a predetermined determination value.

[0140] Furthermore, when the temperature state of the torque sensor is not in an abnormal state, the sensor temperature determination unit may determine whether the temperature state of the torque sensor is in a suitable temperature state using at least one of the determination conditions prepared separately from the abnormal state determination condition and a suitable temperature state determination condition consisting of a predetermined determination value different from the abnormal state determination value. The suitable temperature state may be determined using the same method as the abnormal state determination.

[0141] Under a determination condition in which the output value of a temperature detection unit of the torque sensor is compared with a predetermined threshold value, it is determined whether the output value of the temperature detection unit exceeds the predetermined threshold value. The sensor temperature determination unit may determine that an abnormal state exists when the output value of the temperature detection unit exceeds the predetermined threshold value. Alternatively, the sensor temperature determination unit may determine that a suitable temperature state exists when the output value of the temperature detection unit is below the predetermined threshold value.

[0142] The output value of the temperature detection unit may be a representative temperature of the torque sensor, a temperature output by a temperature sensor arranged at a displacement detector portion of the torque sensor, or temperatures output by a plurality of temperature sensors arranged in the torque sensor.

[0143] The determination condition for comparing the change in the output value of the temperature detection unit of the torque sensor within a specified time period with a specified threshold value may be the change in the output value of the temperature detection unit when the specified time period decreases, or the change in the output value of the temperature detection unit when the specified time period increases. Alternatively, the change in the output value of the temperature detection unit, obtained at the end of a repeated specified action of the robot or when it temporarily stops, may be used. The sensor temperature determination unit may determine an abnormal state when the change in the output value of the temperature detection unit within a specified time period exceeds a specified threshold value. Alternatively, the sensor temperature determination unit may determine a suitable temperature state when the change in the output value of the temperature detection unit within a specified time period is below a specified threshold value.

[0144] In the judgment condition of comparing the compensation value of the torque data that has been temperature-compensated by the temperature compensating unit with a predetermined threshold, the magnitude of the correction amount of the torque data based on the temperature compensation can be monitored. When the torque acting on the joint due to the robot movement is large and the temperature of the torque sensor is high, the compensation value of the temperature compensation of the torque data becomes a value larger than the predetermined threshold. In this case, it can be detected that the error of the torque data has become larger or may become larger due to the deterioration of the temperature state of the torque sensor. Here, the compensation value of the torque data can be any value as long as it is a value calculated based on the torque data that has been temperature-compensated and the torque data that has not been temperature-compensated. For example, the compensation value of the torque data is the difference or ratio between the torque data that has been temperature-compensated and the torque data that has not been temperature-compensated. In addition, the sensor temperature judgment unit can determine that the temperature is in a suitable temperature state when the compensation value of the temperature compensation of the torque data is below the predetermined threshold.

[0145] In the judgment condition for comparing the output value of the temperature detection unit of the torque sensor of one joint axis of the robot with the output values ​​of the temperature detection units of the torque sensors of other joint axes, if the output value of the temperature detection unit of the torque sensor is significantly different from the temperature state of the torque sensors of the other joint axes, the robot is judged to be in an abnormal state. If the output value of the temperature detection unit of the torque sensor is approximately the same as the temperature state of the torque sensors of the other joint axes, the robot is judged to be in a suitable temperature state. The comparison with the torque sensors of other joint axes can be performed with the torque sensors of a specified joint axis, with multiple torque sensors, or with all other torque sensors.

[0146] Preferably, when the torque sensor temperature state is detected as abnormal or when the torque sensor temperature state is detected as appropriate, a predetermined threshold value (determination value) used in each determination condition is set according to the situation or the purpose of the determination. Furthermore, preferably, when multiple determination conditions exist, which determination condition to use, and which determination conditions must simultaneously be met to determine that the torque sensor temperature state is abnormal or appropriate, are pre-set. Furthermore, preferably, the predetermined threshold value used in each determination condition is pre-set to a value that enables the following determinations.

[0147] As described above, the sensor temperature determination unit determines whether the torque data detected by the torque sensor differs from the torque value actually acting on the torque sensor due to the temperature state of the torque sensor, or whether the degree of difference is within an allowable range. Furthermore, the unit determines whether the output of the temperature detection unit that detects the temperature of the torque sensor differs from the value indicating the actual temperature state of the torque sensor, or whether the degree of difference is within an allowable range.

[0148] Furthermore, the sensor temperature determination unit determines whether a condition related to the temperature of the torque sensor makes it impossible to calculate an accurate value when calculating temperature-compensated torque data, or whether a condition has occurred in which the difference from the correct value is significant. Furthermore, the sensor temperature determination unit determines whether a specific condition exists, such as a significant change in the temperature condition of the torque sensor, a deterioration in the temperature condition of the torque sensor, a large difference in temperature measured at multiple locations within the torque sensor, or a non-uniform condition. Under this specific condition, the sensor temperature determination unit determines whether the temperature condition of the torque sensor is likely to become such that an accurate value cannot be calculated when calculating temperature-compensated torque data, or whether it can be predicted. Alternatively, the sensor temperature determination unit determines whether a condition is likely to become such that the difference from the correct value is significant, or whether it can be predicted.

[0149] The predetermined threshold used in each determination condition is preferably set according to the determination condition, the characteristics of the torque sensor, the type of torque sensor, or the location of the robot joint axis equipped with the torque sensor. Furthermore, the predetermined threshold is preferably set taking into account the ambient temperature of the robot's operating environment, the temperature of peripheral devices, the temperature of tools, the temperature of the manipulator, or the temperature of the object being transported. Furthermore, the predetermined threshold is preferably set according to the robot's operating conditions, such as the motion of each joint axis or the load on the joint axis, including the weight of the object being transported and the position of its center of gravity.

[0150] The sensor temperature determination unit can be constructed as follows: when making a judgment using multiple judgment conditions based on the output value of the temperature detection unit of the torque sensor and the value related to the temperature compensation of the torque data performed by the temperature compensation unit, it is determined whether the temperature state of the torque sensor is an abnormal state or a suitable temperature state based on the composite conditions.

[0151] For example, the sensor temperature determination unit can be configured to determine whether the temperature state of the torque sensor is an abnormal state or whether the temperature state of the torque sensor is a suitable temperature state when at least one of the following conditions is met, the conditions being: an output value of a temperature detection unit of the torque sensor is not within a prescribed threshold value, a change in the output value of the temperature detection unit within a prescribed time is not within a prescribed threshold value, or a value related to temperature compensation of the torque data performed by the temperature compensation unit and a value (a value changed due to temperature compensation) for temperature compensation of the torque data detected by the torque detection unit is not within a prescribed threshold value, or a coefficient related to temperature compensation of the torque data detected by the torque detection unit is not within a prescribed threshold value.

[0152] The sensor temperature determination unit can be configured to determine whether the temperature state of the torque sensor is an abnormal state or whether the temperature state of the torque sensor is an appropriate temperature state by comparing the output value of the temperature detection unit of the torque sensor based on the temperature in the torque sensor and the change value of the temperature in the torque sensor within a specified time with a specified threshold value.

[0153] Furthermore, when the torque sensor includes multiple temperature sensors, the values ​​based on the output values ​​of the temperature detection units included in the torque sensor may include the temperatures of multiple locations on the torque sensor, the change in temperature of the multiple locations on the torque sensor over a predetermined period of time, the temperature difference between the multiple locations on the torque sensor and other locations, or the change in temperature difference between the multiple locations on the torque sensor and other locations over a predetermined period of time. Alternatively, the determination of whether the temperature state of the torque sensor is abnormal or whether the temperature state of the torque sensor is at an appropriate temperature may be performed by comparing the values ​​based on the output values ​​of the temperature detection units included in the torque sensor with a predetermined threshold value.

[0154] Furthermore, the sensor temperature determination unit may be configured to determine whether the temperature state of the torque sensor is abnormal or whether the temperature state of the torque sensor is within an appropriate temperature state by comparing a value related to temperature compensation of the torque data performed by the temperature compensation unit with a predetermined threshold value. The value related to temperature compensation of the torque data performed by the temperature compensation unit is a value that is taken into account when calculating the torque data through temperature compensation. The value related to temperature compensation of the torque data performed by the temperature compensation unit includes, for example, the difference between the torque data before and after temperature compensation, a coefficient value multiplied by the torque data value during temperature compensation, and a coefficient value multiplied by the value detected by the displacement detector when converted to torque data through temperature compensation, which value changes according to the temperature compensation temperature.

[0155] The sensor temperature determination unit may compare a value based on an output value of a temperature detection unit included in the torque sensor with a predetermined threshold value, and a value related to temperature compensation of torque data performed by the temperature compensation unit with a predetermined threshold value. Furthermore, the sensor temperature determination unit may be configured to determine whether the temperature of the torque sensor is abnormal or whether the temperature of the torque sensor is within a suitable temperature state based on whether a predetermined number of determination conditions are satisfied.

[0156] The sensor temperature determination unit can compare a value based on the output of a temperature detection unit included in the torque sensor with a predetermined threshold value, and a value related to temperature compensation of torque data performed by the temperature compensation unit with a predetermined threshold value. Numerical values ​​corresponding to the conditions for these comparisons can be pre-assigned as scores. Furthermore, the system can be configured to determine whether the temperature of the torque sensor is abnormal or within a suitable temperature state by comparing the sum of the scores assigned to the conditions for these conditions with a predetermined threshold value for the scores.

[0157] The sensor temperature determination unit may calculate, as the torque sensor temperature condition (quality level), a value obtained based on an output value of a temperature detection unit included in the torque sensor and a value related to temperature compensation of torque data performed by the temperature compensation unit. Furthermore, the system may be configured to determine whether the torque sensor temperature condition is abnormal or whether the torque sensor temperature condition is within a suitable temperature condition by comparing the torque sensor temperature condition value with a predetermined threshold.

[0158] The sensor temperature determination unit may calculate the torque sensor temperature health status based on at least one of an output value of a temperature detection unit included in the torque sensor and a value related to temperature compensation of torque data performed by the temperature compensation unit. Furthermore, the system may be configured to determine whether the temperature status of the torque sensor is abnormal or whether the temperature status of the torque sensor is within an appropriate temperature state by comparing the torque sensor temperature health status with a predetermined threshold.

[0159] Furthermore, when it is determined that the temperature state of the torque sensor is neither abnormal nor in an appropriate temperature state, the motion command unit may modify the motion command of the robot so that at least one of the speed and acceleration is reduced from a predetermined value, in accordance with the calculated degree of goodness of the temperature state of the torque sensor. Alternatively, the motion command unit may modify the motion command of the robot so that at least one of the speed and acceleration is reduced by multiplying the speed and acceleration by a predetermined ratio.

[0160] The sensor temperature determination unit can determine the degree of thermal health of the torque sensor by calculating, based on the output value of the temperature detection unit of the torque sensor and the value related to the temperature compensation of the torque data performed by the temperature compensation unit, a change in these values ​​over a predetermined period of time, or a difference between these values ​​and values ​​of torque sensors at other locations. The system can be configured to determine whether the temperature of the torque sensor is abnormal or whether the temperature of the torque sensor is within a suitable temperature state by comparing these values ​​of thermal health of the torque sensor with a predetermined threshold.

[0161] The sensor temperature determination unit may substitute the output value of the temperature detection unit of the torque sensor, the change in the output value of the temperature detection unit within a predetermined time period, the value of the temperature compensation for the torque data (the value added to or subtracted from the torque data) as a value related to the temperature compensation of the torque data by the temperature compensation unit, and the coefficient related to the temperature compensation of the torque data into a predetermined polynomial (evaluation function) and calculate the value obtained thereby as the torque sensor temperature condition health level. The system may be configured to determine whether the temperature condition of the torque sensor is abnormal or whether the temperature condition of the torque sensor is in an appropriate temperature state by comparing these torque sensor temperature condition health levels with a predetermined threshold value.

[0162] The sensor temperature determination unit may determine a numerical value corresponding to the value of the output value of the temperature detection unit of the torque sensor based on a predetermined numerical value assigned according to a range of values ​​within which the output value of the temperature detection unit exists. Alternatively, the sensor temperature determination unit may determine a numerical value corresponding to the value related to the temperature compensation of the torque data performed by the torque data temperature compensation unit based on a predetermined numerical value assigned according to a range of values ​​within which the torque data is temperature compensated. The sensor temperature determination unit may calculate the value obtained by adding these numerical values ​​as the degree of temperature health of the torque sensor. The sensor temperature determination unit may be configured to determine whether the temperature status of the torque sensor is abnormal or whether the temperature status of the torque sensor is in a suitable temperature state by comparing the numerical value of the degree of temperature health of the torque sensor with a predetermined threshold value.

[0163] In more detail, the sensor temperature determination unit can determine: a plurality of regions obtained by dividing the range in which the value of the output value of the temperature detection unit exists. A prescribed numerical value can be assigned to each region. The sensor temperature determination unit determines: a numerical value of the region corresponding to the value of the output value of the temperature detection unit. Alternatively, the sensor temperature determination unit can determine: a plurality of regions obtained by dividing the range in which the value related to the temperature compensation of the torque data exists. A prescribed numerical value can be assigned to each region. The sensor temperature determination unit determines: a numerical value of the region corresponding to the value related to the temperature compensation of the torque data. The sensor temperature determination unit can calculate a value obtained by adding the numerical value of the region corresponding to the value of the output value of the temperature detection unit and the numerical value of the region corresponding to the value related to the temperature compensation of the torque data as the degree of goodness of the temperature condition of the torque sensor.

[0164] The sensor temperature determination unit may substitute a value based on the output value of the temperature detection unit of the torque sensor and a value related to the temperature compensation of the torque data performed by the temperature compensation unit into a predetermined polynomial (evaluation function) and use the value thus obtained as the torque sensor temperature condition health level. The torque sensor temperature condition health level may be determined to be abnormal or appropriate by comparing the value of the torque sensor temperature condition health level with a predetermined threshold.

[0165] For example, as an evaluation method based on an evaluation function, the sensor temperature determination unit can calculate a value obtained based on the following combination as the degree of goodness of the torque sensor temperature condition, wherein the combination is: a value obtained by multiplying the deviation of the output value of the temperature detection unit based on the torque sensor from the prescribed threshold by a prescribed coefficient, and a value related to the temperature compensation of the torque data performed by the temperature compensation unit from the prescribed threshold by a prescribed coefficient.

[0166] The sensor temperature determination unit may use, as the torque sensor temperature health status, a value obtained by combining a value obtained by multiplying the magnitude of a deviation of an output value of a temperature detection unit of the torque sensor from a predetermined threshold value by a predetermined coefficient, a value obtained by multiplying the magnitude of a change in the output value of the temperature detection unit from a predetermined threshold value by a predetermined coefficient, and a value obtained by multiplying the magnitude of a deviation of a value related to temperature compensation of torque data performed by a temperature compensation unit from the predetermined threshold value by a predetermined coefficient. The value related to temperature compensation of the torque data may be a value obtained by temperature compensating the torque data (a value added to or subtracted from the pre-compensated torque data) or a coefficient related to temperature compensation of the torque data.

[0167] The sensor temperature determination unit can determine whether the output value of the temperature detection unit of the torque sensor is not within a predetermined threshold value, whether the change in the output value of the temperature detection unit within a predetermined time period is not within a predetermined threshold value, or whether the value related to temperature compensation of the torque data performed by the temperature compensation unit is not within a predetermined threshold value. When at least one of these determination conditions is satisfied, the sensor temperature determination unit can calculate a value obtained by adding a predetermined value assigned to each condition to the value of the satisfied condition as the degree of thermal health of the torque sensor. The value related to temperature compensation of the torque data can be a value related to temperature compensation of the torque data or a coefficient related to temperature compensation of the torque data.

[0168] The sensor temperature determination unit may determine whether the output value of the temperature detection unit of the torque sensor is not within a predetermined threshold, whether the change in the output value of the temperature detection unit within a predetermined time period is not within a predetermined threshold, or whether the value related to the temperature compensation of the torque data performed by the temperature compensation unit is not within a predetermined threshold. The value related to the temperature compensation of the torque data may be a value for temperature compensation of the torque data or a coefficient related to the temperature compensation of the torque data. When at least one of these conditions is met, the sensor temperature determination unit may calculate, as the degree of temperature health of the torque sensor, a value obtained by adding the following values: a predetermined value assigned to the range of the output value of the temperature detection unit, a predetermined value assigned to the range of the change in the output value of the temperature detection unit within a predetermined time period, and a predetermined value assigned to the range of the value related to the temperature compensation of the torque data performed by the temperature compensation unit.

[0169] When the temperature detection unit includes two or more temperature sensors, the sensor temperature determination unit obtains values ​​detected by the multiple temperature sensors from the temperature detection unit. The sensor temperature determination unit can then determine whether the temperature state of the torque sensor is abnormal or whether the temperature state of the torque sensor is within a suitable temperature state by determining whether the output values ​​of the multiple temperature sensors deviate from each other by more than a predetermined threshold. For example, if the output values ​​of the multiple temperature sensors deviate from each other by more than a predetermined threshold, the sensor temperature determination unit can determine that the torque sensor is in an abnormal state.

[0170] In robots that have internal torque sensors that measure the torque acting on the robot, the airtightness inside the robot is often improved for the purpose of improving reliability, improving dustproofness, improving water resistance, or counteracting electrical noise. In addition, in order to improve the measurement accuracy of torque, the torque sensor is often installed tightly with the mechanism inside the robot and is configured to accurately transmit the torque. The torque sensor is sometimes configured to easily transmit the heat generated in the actuator. In addition, in the robot's operating environment, the robot is susceptible to temperature changes due to the temperature of the surrounding environment, such as the air temperature, the temperature of peripheral devices, the temperature of tools, the temperature of the manipulator, or the temperature of the object being transported. In addition, depending on the robot's movements, the weight of the object being transported by the robot, and the position of the center of gravity, the load on the robot's joint axis may sometimes be large. In addition, the above-mentioned temperature changes or loads on the joint axis may sometimes change significantly in a short period of time.

[0171] In such cases, the robot's torque sensor experiences significant temperature fluctuations or temperature variations within a wide range. Depending on the temperature of the torque sensor, it can be difficult to properly compensate the torque data for temperature, resulting in inappropriate torque data values. Furthermore, while not considered abnormal, the torque sensor's detection accuracy can sometimes decrease. The robot system of this embodiment can maintain an appropriate temperature control for the torque sensor. This allows for accurate temperature compensation of the torque data, minimizing degradation in torque data accuracy.

[0172] Furthermore, even when the torque sensor is not abnormal, it may be desirable to lower the temperature of the joint containing the torque sensor, or to maximize the accuracy of torque data detection. The robot system of this embodiment determines whether the torque sensor's temperature is at an appropriate temperature, in order to determine that the torque sensor's temperature is not at an appropriate temperature. The robot system can suppress joint temperature increases or maintain the torque sensor's temperature at an appropriate level.

[0173] Furthermore, operators may come into direct contact with the robot during direct teaching, or during collaborative work to stop the robot's movements or change its movements or settings. In these situations, the temperature near the robot's joint axes or the temperature status of the torque sensors on these joint axes are unknown. Consequently, the robot may reach unexpected temperatures or the accuracy of the robot's torque sensors may deteriorate due to temperature fluctuations. For example, after operating the robot at high speed for a long period of time in an operation mode that does not require human contact, the robot's joints and torque sensors may reach high temperatures when used in an operation mode that requires human contact. Furthermore, even in an operation mode that detects human contact, the robot's joints or torque sensors may reach high temperatures during prolonged, prescribed operations that place heavy loads on the joints, or when the robot is driven continuously at high speed for a long period of time. In these cases, even if there are no abnormalities in the torque sensors or robot actuators, the robot may become very hot when touched by a human, or the detection accuracy of the temperature sensor may deteriorate, or the detection accuracy of the torque sensor may decrease.

[0174] Even if the robot's joint temperature is sufficient for actuators such as motors, the torque sensor of the robot, which works in conjunction with a worker, may not be at an appropriate temperature. Furthermore, there are cases where the torque sensor's detection accuracy deteriorates, or even if the torque sensor's detection accuracy is sufficient, it may overheat when the worker interacts with the robot, requiring improvement in the torque sensor's detection accuracy. In this embodiment, the robot system determines whether the torque sensor's temperature is at an appropriate temperature in order to determine that the torque sensor's temperature is not at an appropriate temperature. The robot system can detect when the torque sensor's temperature is not at an appropriate temperature. When the torque sensor's temperature is not at an appropriate temperature, the robot system can modify the robot's behavior without using special devices or mechanisms, or by adding additional devices or mechanisms, to achieve an appropriate temperature when the worker interacts with the robot. Furthermore, the robot system can maintain excellent detection accuracy of the torque data from the torque sensor when the worker interacts with the robot. Furthermore, the robot system of this embodiment can reduce the load on the robot when necessary.

[0175] Furthermore, the sensor temperature determination unit can be located within any device included in the robot system. In this embodiment, the sensor temperature determination unit 34 is located within the control unit 4, which is separate from the robot 1. However, it can also be located within each torque sensor. Furthermore, the sensor temperature determination unit can also be located within a control unit located within the robot, a control unit integral with the robot, or a robot drive unit.

[0176] (Action Command Section)

[0177] The motion command unit 43 changes and outputs motion commands for driving the robot 1 according to the situation. The robot driving unit drives the robot 1 according to the motion commands output by the motion command unit 43. By changing the rotational position of the robot 1 on the joint axis, the position and posture of the robot 1 change.

[0178] In this embodiment, the motion command unit 43 is configured in the control device 4, which is separate from the robot 1. However, the present invention is not limited to this embodiment. The motion command unit 43 may be included in any device as long as it is a device included in the robot system. For example, the motion command unit may be configured in a control device configured within the robot, a control device formed integrally with the robot, or a robot drive unit.

[0179] Furthermore, the motion command unit can be configured to execute the prescribed motion based on the data stored in the storage unit when outputting a motion command to drive the robot in a prescribed motion. Furthermore, the motion command can be generated or modified based on the output of various sensors. Furthermore, the device having the motion command unit can be connected to an external network. The motion command unit can generate the robot's motion command based on motion-related data such as the robot's position and speed, or a motion program, transmitted via the external network.

[0180] If the sensor temperature determination unit 34 determines that the torque sensor temperature state of a torque sensor 20 is abnormal, the motion command unit 43 changes the motion command to stop the robot 1 and outputs the command. On the other hand, if the sensor temperature determination unit 34 determines that the torque sensor temperature state of a torque sensor 20 is abnormal, the motion command unit 43 changes the robot's prescribed motion command to reduce at least one of the speed and acceleration of the robot drive motor 19 of the joint axis having the torque sensor 20 determined by the sensor temperature determination unit 34 to a non-adjustable temperature state to a predetermined value or less. Alternatively, the robot's prescribed motion command is changed to reduce at least one of the speed and acceleration of the robot drive motor 19 of the joint axis having the torque sensor 20 determined by the sensor temperature determination unit 34 to a non-adjustable temperature state by multiplying the speed by a predetermined ratio.

[0181] When the sensor temperature determination unit determines the temperature status of the torque sensors, if there is a torque sensor whose temperature status is determined by the sensor temperature determination unit to be abnormal, the motion command unit changes the motion command to stop the robot and outputs the command. On the other hand, if there is no torque sensor whose temperature status is determined to be abnormal, the motion command unit changes the prescribed motion command of the robot 1 to reduce at least one of the speed and acceleration of the robot drive motor 19 of the joint axis having the torque sensor determined by the sensor temperature determination unit to be not in the appropriate temperature state to below a prescribed value corresponding to the temperature status of the torque sensor. Alternatively, the motion command unit 43 may change the prescribed motion command of the robot to reduce at least one of the speed and acceleration of the robot drive motor 19 of the joint axis having the torque sensor determined by the sensor temperature determination unit to be not in the appropriate temperature state by multiplying the speed and acceleration by a prescribed ratio corresponding to the temperature status of the torque sensor.

[0182] If no torque sensor is determined to be in an abnormal temperature state, the motion command unit 43 changes the prescribed motion command for the robot 1 to reduce the speed and acceleration of the robot drive motor 19 for the joint axis having the torque sensor 20 determined by the sensor temperature determination unit 34 to be not in the appropriate temperature state. In this case, the motion command unit may also change the motion command for the robot drive motors on all joint axes of the robot so that the relative positional relationship when the robot is driven according to the prescribed motion is within a predetermined threshold value.

[0183] Alternatively, when no torque sensor is determined to have an abnormal torque sensor temperature state, and when a torque sensor is determined to have a temperature state that is not within the appropriate temperature state, the motion command unit may modify the motion commands for the robot drive motors of the plurality of joint axes of the robot for all joint axes of the robot so that at least one of the speed and acceleration when the robot is driven according to the prescribed motion is multiplied by a predetermined ratio to thereby reduce the speed. Alternatively, when multiplying at least one of the speed and acceleration by the predetermined ratio to thereby reduce the speed and acceleration, the predetermined ratio may be changed in accordance with the value of the torque sensor temperature health level. For example, the motion command unit may modify the predetermined ratio so that the worse the torque sensor temperature health level, the smaller the speed and acceleration.

[0184] When, in response to a predetermined robot motion command, at least one of the speed and acceleration of a robot drive motor is reduced for a joint axis having a torque sensor determined by the sensor temperature determination unit to be not in a suitable temperature state, there may be multiple joint axes having torque sensors determined by the sensor temperature determination unit to be not in a suitable temperature state. When reducing the speed of the robot drive motor for a joint axis having a torque sensor determined by the sensor temperature determination unit to be not in a suitable temperature state, a value is used that minimizes the speed reduction ratio for the joint axis having a torque sensor determined by the sensor temperature determination unit to be not in a suitable temperature state. Alternatively, the robot motion command may be modified for all joint axes of the robot so that the speed of the robot drive motor is reduced at the minimum ratio for the predetermined robot motion. Alternatively, when reducing the acceleration of a joint axis having a torque sensor determined by the sensor temperature determination unit to be not in a suitable temperature state, a value is used that minimizes the acceleration reduction ratio for the joint axis having a torque sensor determined by the sensor temperature determination unit to be not in a suitable temperature state. Alternatively, the robot motion command may be modified for all joint axes of the robot so that the acceleration of the robot drive motor is reduced at the minimum ratio for the predetermined robot motion.

[0185] Here, the control device 4 may have an action instruction changing unit that changes the action of the robot 1. For example, the action instruction unit 43 or the action control unit 31 may include an action instruction changing unit. The action instruction changing unit is equivalent to a processor that is driven according to an action program. The processor functions as an action instruction changing unit by implementing the control determined in the action program. The action instruction changing unit may change the action of the robot based on the determination result of the sensor temperature determination unit. In addition, it is preferred that after the action instruction changing unit changes the action of the robot, when the sensor temperature determination unit determines that the temperature state of the torque sensor is inappropriate, the action instruction changing unit further reduces at least one of the speed and acceleration of the robot, or stops the robot.

[0186] The motion command changing unit may be configured to change the robot's motion command when calculating the robot's motion command output by the motion command unit. The motion command changing unit may not only adjust the speed and acceleration of the specified motion command but also generate motion commands that change the robot's position, trajectory, speed, acceleration, etc., to perform motions appropriate to the situation.

[0187] The motion command changing unit may create or change the motion command of the robot in accordance with the torque data value. In addition, the motion command changing unit may be configured to change the motion command output by the motion command unit.

[0188] (Example of changing the control of motion instructions)

[0189] Figure 4 This is a flowchart showing control for changing the motion instructions of the first robot system in this embodiment. Figure 4 The control shown can be repeatedly performed at predetermined time intervals. Figure 3 as well as Figure 4 In step 81, the motion command unit 43 generates a motion command for the robot 1 based on the motion program 41. On the other hand, in step 82, the sensor temperature determination unit 34 obtains the temperature from the temperature sensor 22 of the torque sensor 20 and determines the temperature state of the torque sensor.

[0190] In step 83, if the temperature of at least one torque sensor 20 is abnormal, the sensor temperature determination unit 34 transmits this information to the motion command unit 43. Control then transfers to step 84. In step 84, the motion command unit 43 changes the motion command for robot 1 to stop robot 1. In step 87, the motion command unit 43 stops robot 1.

[0191] If the temperature of all torque sensors 20 is outside the abnormal state range in step 83, control transfers to step 85. In step 85, the sensor temperature determination unit 34 determines whether the temperature of all torque sensors 20 is within the appropriate temperature range. If the temperature of all torque sensors is within the appropriate temperature range, the motion command unit 43 does not change the motion command generated in step 81. Control transfers to step 87, where the motion command unit 43 drives the robot 1 according to the motion command generated in step 81.

[0192] If the temperature of at least one torque sensor 20 is not in the appropriate temperature state in step 85, control transfers to step 86. The sensor temperature determination unit 34 transmits this information to the operation command unit 43. For example, if the temperature of at least one torque sensor 20 is within the range between the appropriate temperature state and the abnormal state, control transfers to step 86.

[0193] In step 86, the motion command unit 43 implements control to reduce at least one of the speed and acceleration of the robot drive motor 19 that drives the robot 1. The motion command unit 43 changes the motion of the robot drive motor 19 of the joint axis equipped with the torque sensor 20 whose temperature, as determined by the sensor temperature determination unit 34, is outside the appropriate temperature range. The motion command unit 43 changes the motion command for the robot 1 so that at least one of the speed and acceleration of the robot drive motor 19 is below a predetermined value. Next, in step 87, the motion command unit 43 drives the robot 1 according to the motion command changed in step 86.

[0194] In this manner, when the temperature of at least one torque sensor is neither within the abnormal state range nor within the optimal temperature range, control can be implemented to reduce at least one of the speed and acceleration of the robot drive motor in the joint where the torque sensor is located. This control reduces the temperature of the torque sensor, allowing the robot 1 to be driven so that the temperature of the torque sensor is within the optimal temperature range.

[0195] In this embodiment, the operation mode of changing the operation of the robot 1 so that the temperature of the torque sensor falls within the optimum temperature range is called the temperature adaptation mode. In the temperature adaptation mode, arbitrary control can be performed so that the temperature of the torque sensor disposed on the robot 1 falls within the optimum temperature range.

[0196] Figure 5 This is a flowchart showing other control steps for changing the motion instructions of the first robot system in this embodiment. Figure 5 The control shown can be repeated at predetermined time intervals. Figure 4 Same controls as shown. Figure 5In the other control shown, step 88 is the same as Figure 4 In step 85 , when the temperature of at least one torque sensor 20 is out of the suitable temperature range, control is transferred to step 88 .

[0197] In step 88, the motion command unit 43 modifies the motion of the robot drive motor 19 of the joint axis equipped with the torque sensor whose temperature state was determined by the sensor temperature determination unit 34 to be outside the appropriate temperature range. The motion command unit 43 modifies the robot's motion command by multiplying at least one of the speed and acceleration of the robot drive motor 19 by a predetermined ratio to reduce the speed. In other words, the motion command unit 43 generates a motion command for the robot 1 such that the speed or acceleration is multiplied by a ratio less than 1. Next, in step 87, the motion command unit 43 drives the robot 1 according to the motion command modified in step 88.

[0198] In this way, when the temperature of the torque sensor is neither abnormal nor in the appropriate temperature state, the operation of the robot 1 can be changed so that the temperature of the torque sensor reaches the appropriate temperature state while continuing to drive the robot 1 .

[0199] (Effect of the First Robot System)

[0200] While a robot system is being driven, even if the temperature of the robot's actuator-driven components is normal, the temperature of the torque sensors on the robot's joint axes may deteriorate. In conventional robot systems, this deterioration in the torque sensor's temperature reduces the detection accuracy of the torque sensor, deteriorates the measurement accuracy of torque data, and thus increases errors in temperature data or torque data. This can result in inappropriate detection of torque or force acting on the robot, false detection during contact detection with the surrounding environment, causing the robot to stop, or unexpected motion during direct teaching, where force is applied directly to the robot to cause movement.

[0201] In contrast, the robot system of this embodiment can suppress deterioration in the temperature of the torque sensor located on the joint axis, thereby suppressing a decrease in the detection accuracy of the torque sensor's temperature sensor, and suppressing a decrease in the measurement accuracy of torque data. This can also suppress erroneous detection of torque applied to the robot's components, thereby preventing malfunctions of the robot.

[0202] In addition, when the torque sensor is not in an appropriate temperature state, or the temperature state of the joint of the robot is not in an appropriate temperature state, the temperature state of the torque sensor of the joint axis of the robot and the temperature state of the joint of the robot can be improved without using a torque sensor or a special device, structure or mechanism for cooling the robot.

[0203] The robot system of this embodiment stops the robot when the temperature of the torque sensor of the robot's joint axis reaches an abnormal state. Through this control, it is possible to avoid contact with the operator or surrounding objects with excessive force, and to ensure a safe state in the use of the robot.

[0204] Furthermore, even if the torque sensor's temperature deteriorates beyond the appropriate temperature, the robot may continue to operate as long as it remains within a normal state. For example, when the robot is in contact with a human operator or surrounding equipment, and when detecting a force exceeding a specified value based on the torque acting on the torque sensor, or when performing operations based on the detected torque data, a provisioning margin may be implemented to ensure that the torque sensor's detection error remains within an acceptable range, preventing abnormal conditions. In this case, the torque sensor's measurement accuracy can be optimized, or the robot's joint temperatures can be maintained at an appropriate temperature, allowing the robot to continue operating safely and with improved operability.

[0205] Furthermore, the temperature of the torque sensor located at the joint of the robot may rise or be affected by sudden temperature changes, not only due to the operation of the driving unit including the robot's actuator, but also due to the temperature of the robot's operating environment, the temperature of peripheral devices, tools, manipulators, or the temperature of the surrounding environment such as the object being transported. The temperature state of the torque sensor reflects the temperature of the device other than the temperature of the actuator including the robot's drive motor. When the temperature of parts other than the actuator is high, the temperature state of the torque sensor will also deteriorate. In the robot system of this embodiment, instead of the temperature of the actuator, the temperature state of the torque sensor is abnormal, or the temperature state of the torque sensor is not abnormal but not at the appropriate temperature. When the temperature state of the torque sensor is abnormal, the robot is stopped. When the temperature state of the torque sensor is not at the appropriate temperature, the speed of driving the robot is slowed down or unreasonable movements are prevented. Therefore, it is possible to improve safety while allowing the robot to continue to operate.

[0206] In particular, in collaborative robots that rely on human contact, the use of temperature sensors in the robot's joints, along with the torque sensors, allows the robot's surrounding temperature to be taken into account. This means that when detecting the robot's temperature, the joint temperature can be more appropriately detected. Furthermore, in collaborative robots, when the robot's joint temperature is high and not at an appropriate temperature, the robot's actions can be modified to achieve an optimal temperature. Furthermore, by modifying the robot's actions in accordance with the torque sensor's temperature rather than the drive unit's temperature, the robot's joint temperature can be optimized, taking into account the surrounding environment.

[0207] In addition, the temperature states of the multiple torque sensors of the multiple joints are monitored. Even if the temperature of each joint is within the allowable range, there may be a situation where the temperature state of each torque sensor arranged at the joint is deviated. When the difference in the temperature state is large and the temperature states of the multiple torque sensors are outside the prescribed range and at the same time, the action of the robot can be changed. The action of the robot can be changed in such a way that the temperature states of the multiple joints of the robot are close to each other. If the temperatures of the multiple joints are different from each other, the operator may sometimes feel uncomfortable when touching the collaborative robot. In the robot system of this embodiment, the temperatures of the multiple joints can be made close to each other, thereby reducing the discomfort of the operator and improving the usability of the collaborative robot.

[0208] (Second Robot System)

[0209] Figure 6 The block diagram of the second robot system in this embodiment is shown. In the second robot system 7, the structure of the motion control unit 31 of the control device 4 is different from that of the first robot system 6. In addition, the second robot system 7 has an operator detection device 25 for detecting the operator's motion. The other structures, functions, and effects of the second robot system 7 are the same as those of the first robot system 6 (see Figure 3 ).

[0210] The motion control unit 31 of the second robot system 7 includes, in addition to a conversion unit 32, a temperature compensation unit 33, and a sensor temperature determination unit 34, an motion mode setting unit 35 that sets whether the temperature adjustment mode is enabled or disabled, and a switching timing setting unit 36 ​​that sets the timing for switching between a normal motion mode, in which the robot 1 is driven according to the motion pattern specified in the motion program 41, and a temperature adjustment mode. The motion mode setting unit 35 and the switching timing setting unit 36 ​​each correspond to a processor driven according to the motion program 41. The processor reads the motion program 41 and implements the control specified in the motion program 41, thereby functioning as each unit.

[0211] (Action mode setting section)

[0212] The operation mode setting unit 35 sets the temperature adaptation mode to an active state or an inactive state as the operation mode of the robot 1. The operation mode setting unit 35 sets the temperature adaptation mode to an active state or an inactive state as the operation mode of the robot 1 at a predetermined timing based on the setting of the switching timing setting unit 36. It is preferable that the temperature adaptation mode be set to an active state as needed for the operation mode of the robot 1. However, the operation mode setting unit 35 may always set the temperature adaptation mode to an active state as the operation mode of the robot 1.

[0213] When the temperature adjustment mode is enabled as the robot's motion mode, if the sensor temperature determination unit determines that the torque sensor's temperature is not at an appropriate temperature, the motion command unit limits at least one of the velocity and acceleration of the joint axis having the corresponding torque sensor to reduce the velocity or acceleration, or changes the robot's motion to reduce the load on the joint. The motion command unit 43 controls the torque sensor so that its temperature reaches or approaches the appropriate temperature.

[0214] The motion mode setting unit 35 may be included in any device as long as it is a device included in the robot system. For example, the motion mode setting unit may be configured in a control device separate from the robot, a control device configured within the robot, a control device integrally provided with the robot, or a robot drive unit. Alternatively, a device including the motion mode setting unit, the switching timing setting unit, and the motion command unit may be connected to an external network capable of communicating with the robot.

[0215] (Switch timing setting section)

[0216] The switching timing setting unit 36 ​​sets the timing for switching the temperature adjustment mode to the active state or the inactive state. Here, as the timing for switching the temperature adjustment mode to the active state or the inactive state, a time point or condition such as a predetermined time, a predetermined state, when a predetermined condition is satisfied, or when a predetermined condition fails can be specified.

[0217] The switching timing setting unit may use the time after the robot performs a predetermined action, before the robot performs a predetermined action, or a predetermined time as the timing for switching the thermoregulatory mode to the active or inactive state. Alternatively, the switching timing may be set a predetermined time before or after the robot starts the predetermined action. Alternatively, the switching timing may be set a predetermined time after or before the robot finishes the predetermined action. Alternatively, the switching timing may be set when a predetermined signal is input or when the predetermined signal is disconnected.

[0218] The switching timing setting unit can enable the temperature adaptation mode before a situation in which the robot is likely to come into contact with a human operator or surrounding equipment arises. In particular, the temperature adaptation mode can be enabled in advance to minimize wasted time. Furthermore, the switching timing setting unit can enable the temperature adaptation mode and drive the robot only when necessary.

[0219] As an example of a method for setting switching timing, a command to enable the temperature adaptation mode can be included in the robot's motion program after the command to execute the specified action. If a specified time is required, a command to set the time before or after the action can be included. Alternatively, an explicit execution or setting command can be inserted, such as by enabling the time setting as an attribute of the command to enable the temperature adaptation mode.

[0220] Furthermore, as attributes of the command statements that execute a specified action, conditions such as the timing at which the temperature adaptation mode is enabled or disabled can be set. For example, as attributes of the command statements in the action program, the robot action state that enables or disables the temperature adaptation mode, the time before or after the specified action, the conditions for executing the temperature adaptation mode during the specified action, whether a specified signal is input or disconnected, or the time to switch the setting can be set.

[0221] Furthermore, timings can be set from the robot's control device, an input device connected to the robot, or a device connected to the robot via a communication network, such as after the robot performs a specified action, before the robot performs a specified action, at a specified time, a specified time before or after the robot starts a specified action, a specified time after or before the robot ends a specified action, or when a specified signal is input or disconnected. In this case, for example, an operator can use a communication device connected to the robot via a network to confirm the robot's current task and activate the temperature adaptation mode immediately, at a specified time, or at a desired time by the operator. Furthermore, the operator can set the robot's driving mode to the temperature adaptation mode active before performing a task in collaboration with the robot, and set the torque sensor temperature to the appropriate temperature during the actual task.

[0222] The switching timing setting unit can switch the temperature adaptation mode to active or inactive at a predetermined time. This control allows the robot's temperature adaptation mode to be activated or inactive in accordance with the duration of the collaborative work performed by the operator and the robot. Furthermore, the robot's temperature adaptation mode can be inactive by inputting a signal, for example, when the operator and the robot have completed their work.

[0223] Reference Figure 6The second robot system 7 includes a worker detection device 25 that detects the presence of a worker in the monitored area where the robot 1 is located. In the second robot system 7, when a worker is present in the area where the robot 1 is located, the robot 1's operating mode can be switched from the normal operating mode to the temperature adaptation mode. The worker detection device 25 in this embodiment includes an entry detection device 25a that detects the entry of a worker into the monitored area, and an exit detection device 25b that detects the exit of a worker from the monitored area.

[0224] The entry detection device 25a detects that the operator is entering or has entered the predetermined area where the robot 1 is driven. The switching timing setting unit 36 ​​can set the temperature adjustment mode to the effective state when the entry detection device 25a detects that the operator is entering or has entered the predetermined area where the robot is driven.

[0225] The exit detection device 25b detects that the operator is leaving or has left the predetermined area driven by the robot 1. The switching timing setting unit 36 ​​can disable the temperature adjustment mode when the exit detection device 25b detects that the operator is leaving or has left the predetermined area driven by the robot 1.

[0226] Each of the entry detection device 25a and the exit detection device 25b can be composed of any measuring device, such as a light curtain, a laser scanner, a TOF (Time-of-Flight) camera, a camera that captures two-dimensional images, or a three-dimensional measuring device comprising multiple cameras. The entry detection device 25a and the exit detection device 25b can be any device as long as they can detect or infer that an operator has entered or is entering a predetermined monitoring area, or that an operator has left or is leaving a monitoring area. Furthermore, the method for detecting that an operator is entering or leaving a monitoring area can be any method. For example, a detection method can be used to predict and detect the operator's movements by measuring the operator's direction of movement, measuring the passage of one or more locations, or measuring the distance between the operator and a predetermined location. The method for detecting that an operator has entered or left a monitoring area can be any method that detects whether an operator is present within the monitoring area. Furthermore, the entry detection device 25a and the exit detection device 25b can also be implemented by a single device.

[0227] Furthermore, the entry detection device and exit detection device can be configured to notify the operator of entering, having entered, leaving, or having exited a predetermined area of ​​the robot system from another process control device or process management device. This configuration can detect or infer that the operator has entered or is entering a predetermined monitoring area, or has left or is leaving a monitoring area.

[0228] The areas monitored by the entry detection device 25a and the exit detection device 25b can be the entire area within which the robot can be driven, a portion of the area within which the robot can be driven, or an area predetermined by the operator. By setting the monitored area to a portion of the area within which the robot can be driven, such as an area where the likelihood of contact between the operator and the robot is high, the robot's operating mode can be set to the temperature adaptation mode under limited circumstances.

[0229] Furthermore, when the monitoring area is set to an area predetermined by the operator, the predetermined area can be set outside the robot's drivable area. When the operator passes through the predetermined area, the temperature adaptation mode can be enabled until the operator enters the robot's drivable area. Alternatively, the temperature adaptation mode can be disabled after the operator has reliably left the robot's drivable area.

[0230] The switching timing setting unit may be configured to set the timing for switching the temperature acclimation mode to the active or inactive state so that the temperature state of the torque sensor reaches an appropriate temperature state after the robot performs a predetermined action, before the robot performs a predetermined action, or at a predetermined time. In this case, the timing for switching the temperature acclimation mode to the active or inactive state may be set based on the relationship between the movement of the joint axis having the torque sensor and the temperature state of the torque sensor during the robot's movement.

[0231] The switching timing setting unit is capable of monitoring and recording the rotational position, velocity, and acceleration values ​​of the robot drive motors of each joint axis of the robot when the robot performs a predetermined motion within a predetermined time, such as when the robot is in motion or temporarily stopped. Furthermore, along with these values, the switching timing setting unit is capable of monitoring and recording values ​​related to the temperature state of the torque sensor, such as the output value of the temperature detection unit of the torque sensor and the value related to temperature compensation of torque data by the temperature compensation unit, as well as their temporal changes.

[0232] The switching timing setting unit may include a data table based on data acquired from the current time point to a predetermined time point before, data acquired by executing a predetermined action, or data acquired in the past. The switching timing setting unit may be configured to determine parameters of a relationship between the speed and acceleration of the robot drive motor and the temperature state of the torque sensor for each joint axis based on the acquired data.

[0233] The switching timing setting unit can then estimate, based on the relationship, the change in the temperature state of the torque sensor when at least one of the speed and acceleration of the robot drive motors for each joint axis of the robot is reduced. The switching timing setting unit can calculate the estimated time required for the robot to perform a predetermined action based on the robot's action program, a set or designated action, and action information such as position, speed, and acceleration. The switching timing setting unit can switch the temperature adaptation mode to an active or inactive state so that the temperature state of the torque sensor reaches an appropriate temperature state after the robot performs the predetermined action, before the robot performs the predetermined action, or at a predetermined time.

[0234] For example, the switching timing setting unit may set the robot's operation mode to the temperature adaptation mode effective state before the operator and the robot perform work in cooperation, thereby setting the temperature state of the torque sensor to the appropriate temperature state.

[0235] The switching timing setting unit may be included in any device as long as it is a device included in the robot system. For example, the switching timing setting unit may be included in a control device separate from the robot, a control device located within the robot, a control device integral with the robot, or a device included in the robot system, such as a robot drive unit.

[0236] (Effect of the Second Robot System)

[0237] In the second robot system 7 of this embodiment, timing such as changing the time or conditions for robot movement can be set to achieve an optimal temperature for the torque sensor 20. Normally, the robot's movement is driven without changing the temperature unless the torque sensor's temperature is abnormal. This allows the robot's joints to be efficiently brought to an optimal temperature before a situation arises where there is a high likelihood of contact with a human operator or surrounding equipment. This also allows for excellent measurement accuracy of the torque sensor. Furthermore, the robot's joints can be brought to an optimal temperature only when necessary.

[0238] This control optimizes the temperature of the torque sensor when the robot comes into contact with a worker or peripheral equipment. It also maintains the robot's joints at a suitable temperature, preventing them from becoming overheated by the worker. If the robot's joints experience inappropriate temperature fluctuations due to the surrounding environment, the robot's motion can be modified to ensure safe operation. In particular, it is possible to impose restrictions when changes to the robot's motion are necessary.

[0239] In situations where the robot is less likely to come into contact with an operator or surrounding equipment, it can be moved using normal motion. This can shorten the robot's operating time, allow the robot to perform more tasks, or enable continuous motion even when loads are applied to the robot's joints.

[0240] Furthermore, for joints where the torque sensor's temperature is inappropriate during robot motion, the driver's load is expected to be relatively high. When there's a strong need to reduce the load on the robot's joints, the load on the joints associated with high-load motions can be reduced. This control can prevent robot failures or extend the time until a failure occurs.

[0241] (Third Robot System)

[0242] Figure 7 The block diagram of the third robot system in this embodiment is shown. In the third robot system 8, the structure in which the robot 1 includes a display unit and the control device 4 includes a display control unit is different from the first robot system 6. The other structures, functions and effects of the third robot system 8 are the same as those of the first robot system 6 (see Figure 3 ).

[0243] Robot 1 of the third robot system 8 includes a display unit 50 that displays predetermined information. As described later, the display unit 50 is configured to correspond to the joints of robot 1. In this embodiment, the display unit 50 is configured at or near the joints of robot 1. The display unit 50 can be composed of any display panel, such as a liquid crystal display panel or an organic EL (Electro Luminescence) display panel. Alternatively, if the display unit 50 displays color instead of text or graphics, it can be composed of a plurality of light-emitting diodes or other lamps.

[0244] The motion control unit 31 of the control device 4 includes a display control unit 37 that controls the display of the display unit 50. The display control unit 37 is equivalent to the processor of the arithmetic processing device. The processor reads the motion program 41 and implements the control specified in the motion program 41, thereby functioning as the display control unit 37. The other structures of the third robot system 8 are the same as those of the first robot system (see Figure 3 ).

[0245] (Display unit)

[0246] Figure 8 A schematic diagram showing a robot having a first display unit in this embodiment. Figure 8The robot 1 shown is provided with first display units 51a to 51c having a circular planar shape. The first display units 51a to 51c are provided at respective joints 17 of the robot 1. The first display units 51a to 51c are composed of display panels capable of displaying arbitrary images such as text or patterns.

[0247] The display unit can display at least one of a color, text, graphic, or pattern in a manner that changes based on at least one of the output value of the temperature detection unit 24 of the torque sensor 20 and the determination result of the sensor temperature determination unit 34. Furthermore, the display unit can change the display based on a value related to the temperature state of the torque sensor or the determination result.

[0248] Furthermore, the display unit is preferably positioned for each joint axis having a torque sensor, displaying the temperature status of each torque sensor. The display unit is preferably positioned within a predetermined threshold distance from each joint axis having a torque sensor. In other words, the display unit is preferably positioned near the joint axis. This configuration allows the operator to easily identify the joint axis corresponding to the information displayed on the display unit.

[0249] The display unit can display a value related to the temperature state of the torque sensor or a value related to the determination of the sensor temperature determination unit, or a color, text, graphic, or pattern based on the value. The information displayed on the display unit is, for example, the temperature of each torque sensor and the temperature change value of the torque sensor within a specified time. The specified time interval can be a control cycle or a time of any length such as every few minutes. Alternatively, the specified time can be a timing determined by the robot action, such as when a specified action ends. Alternatively, the information displayed on the display unit can be the value of each temperature sensor constituting the temperature detection unit, the change value of each temperature sensor over a specified time, the difference from other temperature sensors when multiple temperature sensors are configured, or the change value of the difference over time.

[0250] Furthermore, the information displayed on the display unit may be a value related to compensation when temperature compensation is performed on a value related to torque, or a ratio thereof, or a color, text, graphic, or pattern based on the value. For example, the information displayed on the display unit may be a value used to compensate the value related to torque during temperature compensation, a coefficient used to multiply the value related to torque during temperature compensation, a coefficient used to calculate the temperature-compensated value related to torque during temperature compensation, or a coefficient used to multiply the value detected by the displacement detector during temperature compensation.

[0251] In addition, the information displayed on the display unit may be a coefficient value in temperature compensation, a variable value such as a difference or relative ratio when the coefficient changes due to temperature compensation, or a value that changes when temperature compensation is implemented, which is a value related to the calculation of the value related to the torque after temperature compensation. In addition, the information displayed on the display unit may be a color, text, graphic, or pattern based on the value. In addition, the information displayed on the display unit may be the goodness of the value related to the temperature state of the torque sensor, the goodness of the value related to the determination of the sensor temperature determination unit, the goodness of the determination result of the sensor temperature determination unit, or the goodness of the temperature state of the torque sensor. Preferably, the display unit changes at least one of the color, text, graphic, and pattern over time based on the variable value or goodness. Alternatively, preferably, the display unit displays a specified instantaneous state.

[0252] exist Figure 8 In the example shown, the first display units 51a to 51c change color according to the degree of torque sensor temperature status determined by the sensor temperature determination unit. The display units may change color in stages so that the worst torque sensor temperature status is displayed in red.

[0253] The display units 51a-51c can change the color of the display based on the determination of the torque sensor's temperature status. If the condition is good, they display green; if the condition is slightly deteriorating, they display yellow; and if the condition is poor, they display red. Here, the display unit 51a displays red, the display unit 51b displays yellow, and the display unit 51c displays green. Furthermore, the display units can change their brightness based on the torque sensor's temperature status. For example, the display units can be brighter when the torque sensor's temperature status is poor and darker when the torque sensor's temperature status is good.

[0254] Figure 9 A schematic diagram showing a robot having a second display unit according to this embodiment. Figure 9 The robot 1 shown is equipped with strip-shaped second display units 52a-52c. The display units 52a-52c are located near the joint 17, where the torque sensor is located. The display units 52a-52c are located on a component of the robot that can detect torque using the torque sensor located corresponding to the joint axis. The display units 52a-52c are formed to surround components such as the upper arm 11. The display units 52a-52c are wrapped around the component, extending in the circumferential direction of the component.

[0255] exist Figure 9 In the example shown, Figure 8Similarly, the display colors of the displays 52a-52c change based on the torque sensor's temperature determination results. By using the second display units 52a-52c, which are shaped to surround the components of the robot 1, the operator can view the displays 52a-52c from all directions. Even if the robot 1 changes position or posture, the operator can still confirm the displays on the displays 52a-52c.

[0256] Figure 10 A schematic diagram showing a robot having a third display unit in this embodiment. Figure 10 The robot 1 shown is equipped with third display units 53a to 53c having an elongated shape. The display units 53a to 53c can be arranged within a predetermined distance from the joint axis where the torque sensor is arranged. The display units 53a to 53c are arranged near each joint axis where the torque sensor is arranged.

[0257] Each display unit 53a to 53c is configured to extend from the joint axis toward a structural component of the robot that can detect torque through a torque sensor. For example, the display unit 53a is configured to correspond to the torque sensor that detects the torque when the lower arm 12 is driven. The display unit 53a is configured to extend from the joint 17 between the lower arm 12 and the swivel base 13 toward the lower arm 12. The display unit 53a moves together with the lower arm 12. In this example, the display units 53a to 53c are connected to the lower arm 12. Figure 8 Similarly, the display color changes based on the determination result of the temperature state of the torque sensor. In addition, when the direction of the torque detected by the torque sensor is around the center axis of the arm (link) connecting adjacent joint axes, the display portion can be formed so as to surround the joint portion.

[0258] Figure 11 A schematic diagram showing a robot having a fourth display unit in this embodiment. Figure 11 The robot 1 shown is equipped with fourth display units 54a-54c having an elongated shape. The shape and placement of the fourth display units 54a-54c are similar to those of the third display units 53a-53c. The display units 54a-54c can also be placed within a predetermined distance from the joint axis where the torque sensor is located.

[0259] The fourth display units 54a-54c include two or more areas that display at least one of a color, text, graphic, or pattern, changing based on at least one of the output value of the torque sensor's temperature detection unit and the determination result of the sensor temperature determination unit. When displaying the two pieces of information, the display units 54a-54c can be arranged to extend from near the center of the joint toward a component capable of detecting torque by the torque sensor.

[0260] In the display units 54a to 54c, a color corresponding to the temperature of the torque sensor can be displayed on a portion of the display unit 54a to 54c on the side close to the joint axis. For example, if the temperature of the torque sensor is low, it will be displayed in blue, and if the temperature is high, it will be displayed in red. Regarding the other portion of the display unit 54a to 54c on the side away from the joint axis (the portion of the display unit facing the front end of the robot), a color corresponding to the degree of goodness of the state related to temperature compensation of the torque sensor can be displayed. For example, if the temperature compensation is good, it will be displayed in blue, and if the temperature compensation is poor, it will be displayed in red. States between good and poor states are displayed in a color corresponding to the degree of goodness of the state related to temperature compensation of the torque sensor.

[0261] Alternatively, a color based on the output value or determination result may be displayed on another portion on the side opposite to the side where the joint axis is located, and other output values ​​or numerical values ​​based on the determination result may be displayed on top of this color. As another display example, a portion displaying a color or pattern corresponding to a state related to the temperature state of the torque sensor may be displayed with text related to other states of the temperature state of the torque sensor, similar to how multiple states are displayed on the display unit.

[0262] (Example of image displayed on the display unit)

[0263] Next, refer to Figures 12 to 19 , a specific example of an image displayed on the display unit is described. Figures 12 to 19 In, with Figure 8 As with the first display units 51a to 51c, the display unit 55 is shown as a circular display unit located at the joint 17. Furthermore, the display on the display unit 55 changes from when the temperature of the torque sensor is in a good state to when the temperature of the torque sensor is in a poor state. Each figure shows an image when the temperature is in a good state, an image when the temperature is slightly poor, and an image when the temperature is poor.

[0264] The display unit 55 is composed of a display panel such as a liquid crystal display panel that can display any image. The display unit 55 can display at least one of color, text, graphics, and patterns. Figure 7 The display control unit 37 of the operation control unit 31 controls the image displayed on the display unit 50 according to the operation program 41 .

[0265] Figure 12The first image displayed on the display unit is shown. When the temperature condition of the torque sensor is good, the display unit 55 displays "Good Temperature Condition" on a green background. If the temperature condition deteriorates slightly, the image changes as indicated by arrow 92. If the temperature condition deteriorates slightly, the display unit 55 displays "Slightly Poor Temperature Condition" on a yellow background. Furthermore, as the temperature condition deteriorates, the image changes as indicated by arrow 93. If the temperature condition deteriorates, the display unit 55 displays "Poor Temperature Condition" on a red background.

[0266] In this way, the display unit 55 can display arbitrary information such as the temperature status of the torque sensor or the determination results in text. Furthermore, the display unit can display text in combination with color. The display unit 55 is located at each joint. The display unit 55 can then change its display to reflect the status of the joint where the display unit 55 is located. By observing the display on the display unit 55 located at each joint, the operator can understand the status of each joint.

[0267] Figure 13 A second image displayed on the display unit is shown. In the second image, the temperature of the torque sensor 20 and the rotational speed of the robot drive motor 19 are displayed overlapping with the color corresponding to the temperature state of the torque sensor 20. When the temperature state of the torque sensor 20 is good, the display unit 55 displays a temperature of 25°C and a rotational speed of 20 deg / s on a green background. If the temperature state is slightly worse, the display is changed as shown by arrow 92. A temperature of 42°C is displayed overlapping with a yellow background, and a rotational speed of 50 deg / s is displayed. Furthermore, if the temperature state deteriorates, the display is changed as shown by arrow 93. A temperature of 51°C is displayed overlapping with a red background, and a rotational speed of 100 deg / s is displayed. In this way, variables such as the temperature of the torque sensor and the speed of the robot drive motor can be displayed numerically.

[0268] Figure 14 This represents the third image displayed on the display unit. In addition to the temperature of the torque sensor and the rotational speed of the robot drive motor, the display unit 55 also displays various information in the third image. The third image displays information indicating whether the robot drive motor is currently operating (status), the name of the currently executing action program (Prog.), and the time and date. In this way, any information related to the operation of the robot 1 or the operation of the robot 1 can be displayed on the display unit 55. Furthermore, the operator can select the items displayed on the display unit 55 using, for example, the instructions in the action program.

[0269] Figure 15This image shows the fourth image displayed on the display. When a worker is performing direct teaching or collaborative work with a robot, the worker is in direct contact with the robot. The fourth image can be displayed when the worker is in direct contact with the robot. In the fourth image, the background color changes according to the temperature of the torque sensor.

[0270] When the torque sensor's temperature is good or slightly deteriorating, the joint is at a temperature where the operator will not feel hot even if they touch it, so a display indicating that it is touchable is displayed. When the torque sensor's temperature is poor, the joint is at a temperature where the operator will feel hot if they touch it, so a warning is displayed. By observing the display on the display unit 55, the operator can determine whether caution is required when touching the joint. Furthermore, if the torque sensor's temperature deteriorates further, the display unit 55 can display a prohibition on contact by the operator.

[0271] Figure 16 This shows the fifth image displayed on the display unit. In the fifth image, the display unit 55 displays a pattern. The pattern changes depending on the temperature status of the torque sensor. When the temperature is good, a smaller, colored pattern is displayed. As indicated by arrows 92 and 93, the pattern becomes larger and the number of concave and convex shapes increases as the temperature deteriorates. The operator can identify the temperature status of the torque sensor based on the size and shape of the pattern displayed on the display unit 55.

[0272] Figure 17 The sixth image displayed on the display unit is shown. The sixth image changes its shape according to the temperature status of the torque sensor. In the sixth image, a circular shape is displayed when the temperature status of the torque sensor is good. When the temperature status changes and becomes slightly worse, as indicated by arrow 92, an arrow shape is displayed. As the temperature status further deteriorates, as indicated by arrow 93, the arrow shape becomes larger. In this way, the display unit 55 can change the shape of the shape according to the temperature status of the torque sensor at the joint.

[0273] Figure 18 The seventh image displayed on the display unit is shown. In the seventh image, the pattern changes according to the temperature state of the torque sensor. Figure 18 The image shown shows a horizontally extending rod-shaped indicator. As indicated by arrows 92 and 93, the image changes such that the indicator rises as the temperature of the torque sensor deteriorates. Furthermore, the pattern within the indicator changes as the temperature of the torque sensor deteriorates. Here, as the temperature deteriorates, the pattern changes from a dotted pattern to a diagonal line pattern, as indicated by arrow 92, and from a diagonal line pattern to a mesh pattern, as indicated by arrow 93. Furthermore, the displayed color can change depending on the length of the indicator.

[0274] Figure 19 This shows the eighth image displayed on the display unit. The eighth image uses the outline of the display unit 55 to display a facial graphic. The facial expression changes according to the temperature of the torque sensor. As indicated by arrows 92 and 93, the image changes so that the facial expression worsens as the temperature of the torque sensor deteriorates. Furthermore, the displayed color can be changed according to the facial expression.

[0275] (Effect of the third robot system)

[0276] In the third robot system 8, a display unit 50 for displaying the temperature status of the torque sensor 20 provided in the joint 17 of the robot 1 is positioned near the joint 17 or joint axis 17 where the torque sensor 20 is located. This configuration allows the operator to intuitively understand the temperature status of the torque sensor provided in the robot's joint axis or the temperature status of the joint. Alternatively, the operator can intuitively understand the status of temperature compensation of torque data from the torque sensor provided in the robot's joint axis or the torque detection accuracy.

[0277] Furthermore, even when a worker comes into contact with the robot, it is possible to predict in advance whether the part the worker is touching is at an unexpected temperature or the torque sensor's detection accuracy is reduced. For example, the worker can avoid contact with a hot joint and instead contact another joint.

[0278] In the above embodiment, an example in which the temperature state of the torque sensor deteriorates as the temperature of the torque sensor increases is given for explanation, but the present invention is not limited to this method. There is a case where the temperature of the torque sensor is lower, the temperature state of the torque sensor is worse. For example, when the temperature of the place where the robot is configured is too low, there is a case where the temperature of the torque sensor is very low. As a result, there is a case where the error in the torque data output by the torque sensor is large. In this case, regarding the temperature state of the torque sensor, an abnormal state in which the temperature is lower than the optimum temperature state can be set. In addition, as in the above embodiment, when the temperature state of the torque sensor is neither the optimum temperature state nor the abnormal state, control can be implemented to reduce at least one of the speed and acceleration of the robot drive motor on the joint axis where the torque sensor is configured.

[0279] The above-mentioned embodiments can be combined as appropriate. In each of the above-mentioned controls, the order of the steps can be changed as appropriate within the scope of not changing the functions and effects.

[0280] In the above-mentioned figures, the same or equivalent parts are marked with the same reference numerals. In addition, the above-mentioned embodiment is an example and does not limit the invention. In addition, the embodiment includes changes of the embodiment shown in the claims.

[0281] Explanation of symbols

[0282] 1. Robot

[0283] 4 Control device

[0284] 6, 7, 8 robot systems

[0285] 17 Joints

[0286] 18 Rotational position detector

[0287] 19 Robot drive motor

[0288] 20 Torque sensor

[0289] 21 Displacement Detector

[0290] 22 Temperature sensor

[0291] 23 Torque detection unit

[0292] 24 Temperature detection unit

[0293] 25a Enter the detection device

[0294] 25b Exit detection device

[0295] 32 Conversion Department

[0296] 33. Temperature compensation unit

[0297] 34 Sensor temperature determination unit

[0298] 35 Action mode setting unit

[0299] 36 Switching timer setting unit

[0300] 42 Storage

[0301] 43 Action Command Unit

[0302] 50 Display unit

[0303] 51a, 51b, 51c display unit

[0304] 52a, 52b, 52c display unit

[0305] 53a, 53b, 53c display unit

[0306] 54a, 54b, 54c display unit

[0307] 55 display unit.

Claims

1. A robot system having a robot, the robot including a torque sensor corresponding to a joint axis, characterized in that: The robot system has: a torque sensor comprising a torque detection unit and a temperature detection unit; a temperature compensating unit for obtaining temperature-compensated data based on the output value of the torque detecting unit and the output value of the temperature detecting unit; a sensor temperature determination unit configured to determine whether the temperature state of the torque sensor is an abnormal state or an appropriate temperature state based on at least one output value of the temperature detection unit and the temperature compensation unit; as well as An action command unit changes the action command to stop the robot when there is a torque sensor whose temperature state is in an abnormal state, and changes the action command to reduce at least one of the speed and acceleration of the joint axis equipped with the torque sensor when there is a torque sensor whose temperature state is neither in an abnormal state nor in a suitable temperature state.

2. The robot system according to claim 1, wherein: The robot is configured to detect torque acting on the robot using a torque sensor provided on a joint axis of the robot, and a robot system for driving the robot includes: The robot is composed of a plurality of joint axes, wherein the robot includes two or more joint axes with torque sensors; The motion instruction unit outputs a motion instruction for driving the robot; a torque sensor provided on the joint axis of the robot and including the torque detection unit for detecting the torque acting on the torque sensor and the temperature detection unit for detecting the temperature state of the torque sensor; the temperature compensating unit, which obtains temperature-compensated torque data based on the output value of the torque detecting unit and the output value of the temperature detecting unit; and The sensor temperature determination unit uses the abnormal state determination condition to determine whether the temperature state of the torque sensor is an abnormal state, and when the temperature state of the torque sensor is not an abnormal state, uses the appropriate temperature state determination condition to determine whether the temperature state of the torque sensor is an appropriate temperature state, wherein The abnormal state determination condition is composed of the following determination conditions and determination values ​​of prescribed determination conditions, wherein the determination condition is at least one of the following determination conditions: a determination condition for comparing the output value of the temperature detection unit with a prescribed threshold value, a determination condition for comparing a change value of the output value of the temperature detection unit within a prescribed time with a prescribed threshold value, a determination condition for comparing a compensation value of torque data after temperature compensation by the temperature compensation unit with a prescribed threshold value, and a determination condition for comparing the output value of the temperature detection unit with an output value of the temperature detection unit in a torque sensor of another joint axis of the robot. The suitable temperature state determination condition is composed of at least one other determination condition among the separately prepared determination conditions and other predetermined determination values. The action command unit implements the following control: When there is a torque sensor whose temperature state is determined by the sensor temperature determination unit to be an abnormal state, the operation command is changed to stop the robot and output; When there is no torque sensor whose temperature state is determined to be an abnormal state, the prescribed action instruction of the robot is changed to: for the joint axis having a torque sensor determined by the sensor temperature determination unit to be not in a suitable temperature state, at least one of the speed and acceleration of the joint axis is made below a prescribed value; or, the prescribed action instruction of the robot is changed to: for the joint axis having a torque sensor determined by the sensor temperature determination unit to be not in a suitable temperature state, at least one of the speed and acceleration of the joint axis is multiplied by a prescribed ratio to reduce it.

3. The robot system according to claim 2, characterized in that The robot system has: an operation mode setting unit that sets a temperature adaptation mode, which is a mode for driving the robot, to an effective state or an ineffective state; and a switching timing setting unit for setting a timing for switching the temperature adjustment mode to an effective state or an ineffective state; The operation mode setting unit sets the temperature adjustment mode to an active state or an inactive state at a predetermined timing based on the setting of the switching timing setting unit.

4. The robot system according to claim 3, wherein: The switching timing setting unit sets the following timings as the timing for switching the temperature adaptation mode to the valid state or the invalid state: after the robot performs a prescribed action, before the robot performs a prescribed action, a prescribed time, a prescribed time before or after the start of the prescribed action of the robot, a prescribed time after or before the end of the prescribed action of the robot, or when a prescribed signal is input or cut off.

5. The robot system according to claim 3, characterized in that As the timing for switching the temperature adaptation mode to the effective state or the ineffective state, the switching timing setting unit sets the timing for switching the temperature adaptation mode to the effective state or the ineffective state based on the relationship between the movement of the joint axis having the torque sensor during the movement of the robot and the temperature state of the torque sensor, so that the temperature state of the torque sensor becomes the appropriate temperature state after the robot performs a prescribed movement, before the robot performs a prescribed movement, or at a prescribed time.

6. The robot system according to claim 3, wherein: The robot system includes an entry detection device for detecting that an operator is entering or has entered a predetermined area where the robot is driven. The switching timing setting unit enables the temperature adjustment mode at a timing when the entry detection device detects that the worker is entering or has entered a predetermined area where the robot is driven.

7. The robot system according to claim 3, wherein: The robot system includes an exit detection device for detecting that an operator is leaving or has left a predetermined area where the robot is driven. The switching timing setting unit sets the temperature adjustment mode to an inactive state when the exit detection device detects that the worker is leaving or has left a predetermined area where the robot is driven.

8. The robot system according to any one of claims 1 to 7, wherein: The sensor temperature determination unit uses determination conditions and determination values ​​corresponding to a portion of the joint shaft having the torque sensor to determine whether the temperature state of the torque sensor is in an abnormal state or in an appropriate temperature state.

9. The robot system according to any one of claims 1 to 8, wherein: When determining whether the temperature state of the torque sensor is in an abnormal state or in an appropriate temperature state, the sensor temperature determination unit calculates the goodness of the temperature state of the torque sensor based on the output value of the temperature detection unit and at least one of the values ​​related to the temperature compensation of the torque data performed by the temperature compensation unit, and uses it to compare the goodness of the temperature state of the torque sensor with the determination conditions and determination values ​​of the specified threshold.

10. The robot system according to any one of claims 1 to 8, wherein: In determining whether the temperature state of the torque sensor is in an abnormal state or in an appropriate temperature state, the sensor temperature determination unit substitutes the output value of the temperature detection unit, the change value of the output value of the temperature detection unit within a specified time, and the value related to the temperature compensation of the torque data performed by the temperature compensation unit and the value of temperature compensation for the detected torque data or the coefficient related to the temperature compensation for the detected torque data into a specified polynomial, and the value thus obtained is used as the degree of goodness of the temperature state of the torque sensor, and is used to compare the determination conditions and determination values ​​of the degree of goodness of the temperature state of the torque sensor with the specified threshold.

11. The robot system according to claim 9 or 10, characterized in that: The action command unit implements the following control: The predetermined motion command of the robot is changed so that, for a joint axis having a torque sensor determined by the sensor temperature determination unit to be not in a suitable temperature state, at least one of the velocity and acceleration of the joint axis is made equal to or less than a predetermined value corresponding to the degree of goodness of the torque sensor temperature state; or The prescribed motion instruction of the robot is changed to: at least one of the velocity and acceleration of the joint axis having a torque sensor determined by the sensor temperature determination unit to be not in an appropriate temperature state is multiplied by a prescribed ratio corresponding to the degree of goodness of the torque sensor temperature state, thereby reducing it.

12. The robot system according to any one of claims 1 to 11, characterized in that: The motion command unit, in response to a predetermined motion command of the robot, reduces at least one of the speed and acceleration of a joint axis having a torque sensor determined by the sensor temperature determination unit to be not in a suitable temperature state, when there are multiple joint axes having torque sensors determined by the sensor temperature determination unit to be not in a suitable temperature state. When reducing the speed of the joint axis having the torque sensor determined by the sensor temperature determination unit to be not in the appropriate temperature state, the action command of the robot is changed to reduce the speed of all joint axes for the prescribed action of the robot by using a value having the minimum ratio of reducing the speed of the joint axis having the torque sensor determined by the sensor temperature determination unit to be not in the appropriate temperature state. When reducing the acceleration of the joint axis having a torque sensor that is determined by the sensor temperature determination unit to be not in a suitable temperature state, the minimum value of the ratio of reducing the acceleration of the joint axis having the torque sensor that is determined by the sensor temperature determination unit to be not in a suitable temperature state is used, and the action instruction of the robot is changed to: reducing the acceleration of all joint axes for the prescribed action of the robot.

13. The robot system according to any one of claims 1 to 12, characterized in that: The robot includes a display unit configured to display at least one of a color, a character, a graphic, and a pattern in accordance with at least one of an output value of the temperature detection unit and a determination result of the sensor temperature determination unit. The display unit is arranged within a distance range within a predetermined threshold from a joint axis having a torque sensor.

14. The robot system according to any one of claims 9 to 11, characterized in that: The robot includes a display unit that changes color in stages according to the degree of temperature condition of the torque sensor determined by the sensor temperature determination unit, such that the display color is red when the temperature condition of the torque sensor is poor. The display unit is arranged within a distance range within a predetermined threshold from a joint axis having a torque sensor.

Images