Robot system

Abstract

To switch movement modes of a robot without requiring a user to be conscious about imparting an external force in a special mode or the current movement mode in a robot system capable of direct teaching.SOLUTION: A robot system (10) includes: a robot (20) having an arm; an external force detection part (36) detecting an external force imparted to the arm; a portion detection part (37) detecting which the external force detected by the external force detection part is imparted in the arm to, a first portion or a second portion nearer an end side than the first part; and a control part (50) which moves the arm in a first movement mode on the basis of the external force detected by the external force detection part when the first portion is detected by the portion detection part in the case that direct teaching is performed, and moves the arm in a second movement mode in which the arm is less likely to move than in the first movement mode on the basis of the external force detected by the external force detection part when the second portion is detected by the portion detection part.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a robot system capable of performing direct teaching.

Background Art

[0002] In this type of robot system, for example, when moving the tool at the tip of the robot arm from a predetermined work location to another work location, it is desirable to be able to move the robot at high speed, and when aligning the position of the tool with the workpiece, it is desirable to be able to move the robot at low speed. Therefore, in the robot system described in Patent Document 1, when the external force detected by the six-axis force sensor is a double tap by the external force twice within a predetermined time, the operation mode is switched to a different operation mode according to the position where the double tap occurred.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the robot system described in Patent Document 1, a double tap by an external force twice within a predetermined time is recognized as a command for switching the operation mode (moving mode) of the robot, distinguishing it from the external force applied to move the robot in direct teaching. For this reason, in order to switch the operation mode of the robot, the user needs to apply an external force in a special mode different from the external force for moving the robot in direct teaching. Furthermore, when direct teaching is interrupted, there is also a problem that it is difficult for the user to know which operation mode the current operation mode is, and it is difficult to judge whether it is necessary to switch the operation mode.

[0005] This invention was made to solve these problems, and its main objective is to enable a robot system capable of direct teaching to switch the robot's movement mode without requiring the user to apply a special type of external force or be aware of the current movement mode. [Means for solving the problem]

[0006] The first means to solve the above problem is, A robotic system capable of direct teaching, A robot with an arm, An external force detection unit for detecting an external force applied to the arm, A part detection unit detects whether the external force detected by the external force detection unit was applied to the first part of the arm or to the second part located closer to the tip than the first part, When performing direct teaching, the control unit moves the arm in a first movement mode based on the external force detected by the external force detection unit when the first part is detected by the part detection unit, and moves the arm in a second movement mode that is less mobile than the first movement mode based on the external force detected by the external force detection unit when the second part is detected by the part detection unit. It is equipped with.

[0007] According to the above configuration, the robot system is capable of direct teaching. The robot has an arm. The external force detection unit detects the external force applied to the arm.

[0008] Here, the part detection unit detects whether the external force detected by the external force detection unit was applied to the first part of the arm or to the second part located at the tip of the first part. When the part detection unit detects the first part, the control unit moves the arm in a first movement mode based on the external force detected by the external force detection unit when performing direct teaching. For this reason, when an external force applied by the user to move the arm during direct teaching (hereinafter referred to as "movement external force") is applied to the first part, the control unit switches to the first movement mode and moves the arm based on the movement external force. In other words, the user does not need to apply an external force of a special type different from the movement external force; by applying the movement external force to the first part, the arm can be moved in a first movement mode based on the movement external force.

[0009] Furthermore, when the part detection unit detects the second part, the control unit moves the arm in a second movement mode that is less mobile than the first movement mode, based on the external force detected by the external force detection unit. Therefore, in direct teaching, if the external force for movement is applied to the second part which is closer to the tip than the first part, the control unit switches to a second movement mode that is less mobile than the first movement mode and moves the arm based on the external force for movement. In other words, the user does not need to apply an external force of a special type different from the external force for movement; by applying the external force for movement to the second part, the arm can be moved in a second movement mode based on the external force for movement.

[0010] Furthermore, the user can move the arm in the desired movement mode by selecting either the first or second part according to the desired movement mode and applying the movement force, thus eliminating the need to be aware of the current movement mode. Moreover, by applying the movement force to the first part, the user can move the arm in the first movement mode, and by applying the movement force to the second part, which is closer to the tip than the first part, the user can move the arm in the second movement mode, which is more difficult to move than the first movement mode. Therefore, the user can intuitively switch between the first and second movement modes through natural operation during direct teaching.

[0011] Specifically, as in the second means, the arm may have a plurality of links connected so as to be rotatable relative to each other, the first part being the links other than the tip of the plurality of links, and the second part being the link at the tip of the plurality of links. With such a configuration, when the user wants to fine-tune the position of the link at the tip, they can intuitively move the arm in the second mode of movement by applying an external force to move the link at the tip. Also, when the user wants to move the arm a large distance, they can intuitively move the arm in the first mode of movement by applying an external force to move the links other than the tip of the arm.

[0012] When the external force detection unit detects external forces based on the force and moment detected by the force sensor, the following problems arise. Specifically, if the force sensor is attached to the tip link, the force sensor can only detect forces and moments applied to the tip link (second part) or to the tool, etc., further to the tip than the tip link, and cannot detect forces and moments applied to the first part, which is closer to the base than the second part. Furthermore, if the force sensor is attached to a link closer to the base, the force sensor is required to have high rigidity to withstand large forces and high detection accuracy to detect minute external forces.

[0013] In this regard, the third means includes three or more links, and a force sensor for detecting the force and moment applied to the arm is provided in the middle of the third link from the tip, and the external force detection unit detects the external force based on the force and moment detected by the force sensor.

[0014] With the above configuration, for example, the link at the tip is designated as the second part, and the part of the third link from the tip closer to the tip than the force sensor, and the second link from the tip are designated as the first part, so that the force and moment applied to the first and second parts can be detected by the force sensor. Furthermore, since the force sensor is provided on a link close to the tip, high rigidity is not required for the force sensor, and the force and moment applied to the first and second parts can be detected by the force sensor with high detection accuracy.

[0015] Furthermore, since the force sensor can detect with high accuracy the force and moment applied to the tip link (second part) or to the tool or other part further forward than the tip link, the force sensor can be used not only during direct teaching but also during the robot's automated operation to detect the force and moment acting on the tool or other part.

[0016] In the fourth means, the first movement mode is a movement mode in which the arm is moved at a first speed, and the second movement mode is a movement mode in which the arm is moved at a second speed lower than the first speed.

[0017] With the above configuration, if the user wants to fine-tune the position of the second part, they can move the arm at a second speed lower than the first speed by applying a movement force to the second part. Also, if the user wants to move the arm a larger distance, they can move the arm at a first speed higher than the second speed by applying a movement force to the first part. In this case, the user does not need to apply a special type of external force or be aware of the current movement mode, and can switch the arm's movement speed through natural operation during direct teaching.

Brief Description of the Drawings

[0018] [Figure 1] Schematic diagram of a robot. [Figure 2] Block diagram showing the configuration of a robot system. [Figure 3] Block diagram showing the configuration of a machine learning device. [Figure 4] Flowchart showing the procedure of machine learning. [Figure 5] Flowchart showing the procedure of direct teaching. [Figure 6] Schematic diagram of a modified example of a robot. [Figure 7] Block diagram showing the configuration of a modified example of a robot system. [Figure 8] Block diagram showing the configuration of another modified example of a robot system. [Figure 9] Schematic diagram of another modified example of a robot.

Modes for Carrying Out the Invention

[0019] Hereinafter, an embodiment embodied in a robot system capable of executing direct teaching will be described with reference to the drawings.

[0020] First, the configuration of a 6-axis vertical articulated robot included in the robot system will be described.

[0021] As shown in Figure 1, the robot 20 comprises a base B fixed to the floor, a first link 21 supported so as to be able to pivot around a first axis J1 perpendicular to the base B, a second link 22 supported so as to be able to swing around a second axis J2 horizontal to the first link 21, a third link 23 supported at the end of the second link 22 so as to be able to swing around a third axis J3 parallel to the second axis J2, a fourth link 24 supported so as to be able to twist and rotate around a fourth axis J4 in the direction in which the third link 23 extends, a fifth link 25 (wrist) supported at the end of the fourth link 24 so as to be able to swing around a fifth axis J5 parallel to the second axis J2, and a sixth link 26 (flange) supported so as to twist and rotate around a sixth axis J6 in the direction in which the fifth link 25 extends. The first to sixth links 26 constitute the arm of the robot 20. In other words, the arm has first links 21 to sixth links 26 that are connected so as to be rotatable relative to each other.

[0022] A 6-axis force sensor 31 for detecting force and moment is positioned in the middle of the fourth link 24 (the third link from the tip, a predetermined link). The force sensor 31 can detect forces and moments applied to the part of the arm closer to the tip than the force sensor 31, i.e., the part of the fourth link 24 (the third link from the tip) closer to the tip than the force sensor 31, the fifth link 25, and the sixth link 26. If the force sensor 31 is attached to the sixth link 26 at the tip, the force sensor 31 can only detect forces and moments applied to the sixth link 26 at the tip or to the tool, etc., further towards the tip than the sixth link 26. Furthermore, if the force sensor 31 is attached to a link close to the base, such as the first link 21, the force sensor 31 is required to have high rigidity to withstand large forces and high detection accuracy to detect minute external forces.

[0023] A torque sensor 32E is provided between the fourth link 24 and the fifth link 25 to detect the torque acting between the fourth link 24 and the fifth link 25. A torque sensor 32F (not shown) is provided between the fifth link 25 and the sixth link 26 to detect the torque acting between the fifth link 25 and the sixth link 26. The torque sensors 32E and 32F are collectively referred to as torque sensor 32. In other words, the torque sensor 32 detects the torque acting between the interconnected links.

[0024] As shown in Figure 2, the robot system 10 is equipped with a direct teaching control unit 50. The direct teaching control unit 50 (control unit) allows the user to select a direct teaching mode in which they manually move the robot 20 by directly applying external force. When the direct teaching mode is selected, the robot can be easily taught an operation program by sequentially storing the position information of each axis of the robot 20 through teaching operations at each manually moved position.

[0025] The direct teaching control unit 50 then switches the operation mode (movement pattern) according to the part of the robot arm 20 to which the external force applied by the user to move the arm during direct teaching (hereinafter referred to as "movement external force") is applied.

[0026] The robot 20 is equipped with a joint angle sensor 33, an external force detection unit 36, and a contact area detection unit 37.

[0027] The joint angle sensor 33 (angle sensor) includes joint angle sensor 33A for detecting the angle (joint angle) between base B and first link 21, joint angle sensor 33B for detecting the angle between first link 21 and second link 22, joint angle sensor 33C for detecting the angle between second link 22 and third link 23, joint angle sensor 33D for detecting the angle between third link 23 and fourth link 24, joint angle sensor 33E for detecting the angle between fourth link 24 and fifth link 25, and joint angle sensor 33F for detecting the angle between fifth link 25 and sixth link 26. In other words, the joint angle sensor 33 detects the angle between links that are connected to each other.

[0028] The external force detection unit 36 ​​detects the external force applied to the arm (the external force acting on the robot 20) based on the force and moment detected by the force sensor 31. The external force detection unit 36 ​​may also take into account the torque detected by the torque sensor 32 when detecting the external force applied to the arm.

[0029] The contact area detection unit 37 (area detection unit) detects whether the external force detected by the external force detection unit 36 ​​is applied to the first area or the second area which is closer to the tip than the first area on the arm. The first area is the fourth link 24 and the fifth link 25 (links other than the tip) among the first to sixth links 26 (multiple links). The second area is the sixth link 26 (the link at the tip) among the first to sixth links 26.

[0030] Specifically, the contact area detection unit 37 (position detection unit) inputs the external force detected by the external force detection unit 36, the joint angle detected by the joint angle sensor 33, and the torque detected by the torque sensor 32 into the trained AI model 37a to detect whether the external force detected by the external force detection unit 36 ​​was applied to the first or second part of the arm (the position on which it acted on the robot 20). The contact area detection unit 37 outputs the detected area to the direct teaching control unit 50.

[0031] When the direct teaching control unit 50 performs direct teaching, if a first part is detected by the contact part detection unit 37, it moves the arm (robot 20) in a high-speed operation mode (first movement mode) based on the external force detected by the external force detection unit 36, and if a second part is detected by the contact part detection unit 37, it moves the arm in a low-speed operation mode (second movement mode) which is less mobile than the high-speed operation mode, based on the external force detected by the external force detection unit 36. The high-speed operation mode is an operation mode (movement mode) in which the arm is moved at a first speed V1. The low-speed operation mode is an operation mode (movement mode) in which the arm is moved at a second speed V2 which is lower than the first speed V1. Note that the first speed V1 and the second speed V2 may be constant or may be changed according to the external force detected by the external force detection unit 36, but the second speed V2 is lower than the first speed V1 (V2 <V1)。

[0032] Next, a machine learning device for generating the trained AI model 37a will be described. Figure 3 is a block diagram showing the configuration of the machine learning device 60. The machine learning device 60 comprises a data acquisition unit 70 and a learning unit 80. The machine learning device 60 may be provided separately from the robot 20 in the robot system 10, or it may be mounted on the robot 20.

[0033] The machine learning device 60 consists of a computer having a processor (CPU, GPU, etc.), a memory unit (ROM, RAM, etc.), and input devices (keyboard, mouse, touch panel, etc.), or software (programs) such as a learning algorithm.

[0034] The data acquisition unit 70 generates random external force data representing the range of external forces that may act on the robot 20. Specifically, it comprehensively and randomly generates external forces within the range that a user can expect to apply to the robot 20 during direct teaching.

[0035] The data acquisition unit 70 generates random joint angle data representing the range of angles that can be formed between the interconnected links 21 to 26. Specifically, it comprehensively and randomly generates angles (joint angles) between links within the range of postures that can be assumed for the robot arm 20 during direct teaching.

[0036] The data acquisition unit 70 generates contact area data for the range in which external forces can act on the robot 20. Specifically, the first and second parts are generated as the positions in which the user applies external forces to the robot 20 during direct teaching.

[0037] The external forces acting on the robot 20, the angles between links, and the positions where these external forces act on the robot 20 can be generated as described above by considering the operating mode of the robot 20 in direct teaching. In contrast, the torque between links is influenced by links other than adjacent links, and it is not easy to generate it directly even by considering the operating mode of the robot 20. On the other hand, the inventors of this application focused on the fact that it is easy to calculate the torque between links based on the external forces acting on the robot 20, the angles between links, and the positions where these external forces act.

[0038] Therefore, the data acquisition unit 70 calculates joint torque data, which is the torque acting on each axis of the robot 20, based on the generated random external force data, generated random joint angle data, and generated contact point data. This calculation can be easily performed using known general methods. Specifically, the random external force data, random joint angle data, and contact point data are combined, and joint torque data is calculated for each combination.

[0039] The data acquisition unit 70 performs preprocessing on random external force data, random joint angle data, contact site data, and joint torque data, respectively. For example, for random external force data and joint torque data, a standardization process is performed to convert the data scale to a value close to the range of -1 to +1. Random joint angle data is converted to sine and cosine waveforms to suppress discontinuous changes in the data and to standardize the data scale to the range of -1 to +1. For contact site data, one-hot vectorization is performed to represent the data as a vector in which only the component corresponding to each contact site is 1 and all other components are 0.

[0040] The data acquisition unit 70 then acquires pre-processed random external force data, random joint angle data, joint torque data, and contact site data as training data (learning dataset). Specifically, the random external force data, random joint angle data, and joint torque data are example data (input data), and the contact site data is the correct answer data (output data).

[0041] The learning unit 80 learns an AI model 80a that represents the relationship between external force, joint angle, joint torque, and contact area, based on training data. In other words, the learning unit 80 generates a trained AI model 80a by performing supervised learning. For such supervised learning, algorithms such as deep learning, support vector machines (SVM), and Gaussian mixture models (GMM) can be used.

[0042] The robot 20 then incorporates the AI ​​model 80a (pre-acquired predetermined relationships) learned by the learning unit 80 as the learned AI model 37a of the contact area detection unit 37. The contact area detection unit 37 detects (estimates) the part of the robot 20 that the user has contacted (the position where the external force acted on the robot 20) by inputting the external force detection value, joint angle detection value, and joint torque detection value into the learned AI model 37a. It should be noted that formulating a calculation formula to determine the position where the external force acted from the external force detection value, joint angle detection value, and joint torque detection value requires setting complex conditions and is not easy.

[0043] Figure 4 is a flowchart showing the machine learning procedure performed by the machine learning device 60. The details of each process are as described above.

[0044] The data acquisition unit 70 generates random external force data, random joint angle data, and contact site data (S10-S12). The data acquisition unit 70 calculates joint torque data (S13). The data acquisition unit 70 performs preprocessing on the random external force data, random joint angle data, and contact site data (S14). The learning unit 80 learns the AI ​​model 80a based on the preprocessed random external force data, random joint angle data, joint torque data, and contact site data (S15).

[0045] Figure 5 is a flowchart showing the direct teaching procedure. This series of processes is performed by the direct teaching control unit 50.

[0046] First, it is determined whether or not force has been detected by the force sensor 31 (S20). If it is determined that no force has been detected by the force sensor 31 (S20: NO), the process in S20 is executed again.

[0047] On the other hand, in the determination in S20, if it is determined that force has been detected by the force sensor 31 (S20:YES), it is determined whether the part of the robot 20 that the user has contacted is the sixth link 26 or not (S21). In this determination, if it is determined that the part of the robot 20 that the user has contacted is the sixth link 26 (S21:YES), the arm of the robot 20 is moved in low-speed operation mode (S22). On the other hand, in the determination in S21, if it is determined that the part of the robot 20 that the user has contacted is not the sixth link 26 (S21:NO), the arm of the robot 20 is moved in high-speed operation mode (S23).

[0048] Next, the position and orientation of the robot 20's arm are taught according to the user's operation (S24). It is determined whether the user's teaching operation has been completed (S25). If it is determined that the user's teaching operation has not been completed (S25: NO), the process is repeated from S20. On the other hand, if it is determined that the user's teaching operation has been completed (S25: YES), this series of processes is terminated (END).

[0049] The embodiment described in detail above has the following advantages.

[0050] The contact area detection unit 37 detects whether the external force detected by the external force detection unit 36 ​​is applied to the first part of the arm or to the second part located at the tip of the first part. When the direct teaching control unit 50 performs direct teaching, if the first part is detected by the contact area detection unit 37, it moves the arm in high-speed operation mode based on the external force detected by the external force detection unit 36. Therefore, when an external force applied by the user to move the arm in direct teaching (hereinafter referred to as "movement external force") is applied to the first part, the direct teaching control unit 50 switches to high-speed operation mode and moves the arm based on the movement external force. In other words, the user does not need to apply an external force of a special nature different from the movement external force; by applying the movement external force to the first part, the arm can be moved in high-speed operation mode based on the movement external force.

[0051] The direct teaching control unit 50 moves the arm in a low-speed operation mode, which is less mobile than the high-speed operation mode, based on the external force detected by the external force detection unit 36 ​​when the second part is detected by the contact part detection unit 37. Therefore, in direct teaching, when the external force for movement is applied to the second part, which is closer to the tip than the first part, the direct teaching control unit 50 switches to a low-speed operation mode, which is less mobile than the high-speed operation mode, and moves the arm based on the external force for movement. In other words, the user does not need to apply an external force of a special nature different from the external force for movement; by applying the external force for movement to the second part, the arm can be moved in a low-speed operation mode based on the external force for movement.

[0052] The user can move the arm in the desired operating mode by selecting either the first or second part and applying an external force for movement according to the desired operating mode, thus eliminating the need to be aware of the current operating mode. Moreover, by applying an external force for movement to the first part, the user can move the arm in high-speed mode, and by applying an external force for movement to the second part, which is closer to the tip than the first part, the user can move the arm in a slower operating mode, which is more difficult than high-speed mode. Therefore, the user can intuitively switch between high-speed and low-speed operating modes in real time through natural operation during direct teaching.

[0053] The user can intuitively move the arm in low-speed mode by applying a movement force to the sixth link 26 when they want to fine-tune its position. Furthermore, the user can intuitively move the arm in high-speed mode by applying a movement force to the fifth link 25 or the fourth link 24 when they want to move the arm a larger distance.

[0054] The sixth link 26 is designated as the second part, and the part of the fourth link 24 closer to the tip than the force sensor 31 and the fifth link 25 are designated as the first part, allowing the force and moment applied to the first and second parts to be detected by the force sensor 31. Furthermore, since the force sensor 31 is located on the fourth link 24, which is close to the tip, high rigidity is not required for the force sensor 31, and the force and moment applied to the first and second parts can be detected by the force sensor 31 with high detection accuracy.

[0055] Since the force and moment applied to the sixth link 26 or the tool or other part at the tip of the sixth link 26 can be detected with high accuracy by the force sensor 31, the force sensor 31 can be used not only during direct teaching but also during the automatic operation of the robot 20 to detect the force and moment acting on the tool or other part.

[0056] • When the user wants to fine-tune the position of the second part, they can move the arm at a second speed V2 lower than the first speed V1 by applying a movement force to the second part. Conversely, when the user wants to move the arm a larger distance, they can move the arm at a first speed V1 higher than the second speed V2 by applying a movement force to the first part. In this case, the user can switch the arm's movement speed through natural operation during direct teaching, without needing to apply a special type of external force or be aware of the current operating mode.

[0057] The learning unit 80 learns an AI model 80a that represents the relationship between external force, joint angle, joint torque, and contact position based on the training data acquired by the data acquisition unit 70. Learning the AI ​​model 80a based on the training data does not require setting complex conditions, and a known learning algorithm can be used. Therefore, even if the posture of the robot 20 changes arbitrarily, the location where the external force acts on the robot 20 can be identified by inputting the detected external force, the detected angle between links, and the detected torque between links into the trained AI model 37a.

[0058] The data acquisition unit 70 calculates and acquires joint torque data based on random external force data, random joint angle data, and contact point data. Therefore, it is possible to easily acquire torque data between links to be used as training data.

[0059] The contact area data consists of a first part of the robot 20 and a second part of the robot 20 located at the tip of the first part. With this configuration, by inputting the detected external force, the detected angle between links, and the detected torque between links into the trained AI model 37a, it is possible to identify whether the external force acted on the first or second part of the robot 20. Furthermore, since the contact area data consists only of the first and second parts, it is easy to have the data acquisition unit 70 acquire the contact area data.

[0060] The robot system 10 is equipped with a machine learning device 60. The contact area detection unit 37 inputs the external force detected by the external force detection unit 36, the joint angle detected by the joint angle sensor 33, and the torque detected by the torque sensor 32 to a trained AI model 37a (AI model 80a trained by the learning unit 80) to detect the position where the external force detected by the external force detection unit 36 ​​acts on the robot 20. Therefore, in the robot system 10, the position where the external force acts on the robot 20 can be detected using the trained AI model 37a, and the accuracy of detecting the position where the external force acts on the robot 20 can be improved.

[0061] Generally, robots are equipped with joint angle sensors and torque sensors, which can reduce costs compared to detecting the position where an external force acts on the robot 20 using a contact sensor that detects the position of contact with the robot 20.

[0062] Furthermore, the above embodiment can also be implemented with the following modifications. Parts identical to those in the above embodiment are denoted by the same reference numerals, and their description is omitted.

[0063] The portion of the fourth link 24 that is closer to the tip of the force sensor 31 can be designated as the first portion, and the fifth link 25 and the sixth link 26 can be designated as the second portion.

[0064] As shown in Figure 6, the robot 120 does not necessarily have to be equipped with a force sensor 31. In this case, as shown in Figure 7, the external force detection unit 36 ​​detects the external force applied to the arm based on the torque detected by the torque sensors 32 (32A to 32E). With the above configuration, the external force detection unit 36 ​​can use the torque sensors 32 equipped in the robot 120 to detect the external force applied to the arm based on the torque detected by the torque sensors 32.

[0065] Furthermore, as shown in Figure 8, the robot 220 may not have a force sensor 31, but may have a contact sensor 34 that detects the part that has been in contact with the arm. In this case, the contact part detection unit 37 detects, based on the part detected by the contact sensor 34, whether the external force detected by the external force detection unit 36 ​​was applied to the first part or the second part of the arm. With the above configuration, it is possible to accurately detect, based on the part detected by the contact sensor 34, whether the external force detected by the external force detection unit 36 ​​was applied to the first part or the second part.

[0066] In addition, in the configuration shown in Figures 7 and 8, the fourth link 24 and the fifth link 25 can be designated as the first part, and the sixth link 26 as the second part. Alternatively, the third link 23 and the fourth link 24 can be designated as the first part, and the fifth link 25 and the sixth link 26 as the second part.

[0067] As shown in Figure 9, in the robot 320, the part of the arm closer to the base end than the force sensor 31 can be designated as the first part, and the part of the arm closer to the tip than the force sensor 31 can be designated as the second part. The contact part detection unit 37 can also detect whether the external force detected by the external force detection unit 36 ​​was applied to the first part or the second part of the arm, based on the torque detected by the torque sensor 32 (32A~32E), the force and moment detected by the force sensor 31, and a predetermined relationship between these.

[0068] According to the above configuration, the force and moment applied to the second part can be detected by the force sensor 31. On the other hand, the force and moment applied to the first part are not detected by the force sensor 31. Therefore, if the torque sensor 32 detects a torque corresponding to the external force for movement and the force sensor 31 does not detect a force and moment, it can be assumed that an external force for movement has been applied to the first part. Accordingly, the contact part detection unit 37 can detect whether the external force detected by the external force detection unit 36 ​​was applied to the first part or the second part of the arm, based on the torque detected by the torque sensor 32, the force and moment detected by the force sensor 31, and a predetermined relationship between these.

[0069] • As a high-speed operation mode (first movement mode), an operation mode is adopted in which the arm is moved while generating a first movement resistance Rm1, and as a low-speed operation mode (second movement mode), an operation mode is adopted in which the arm is moved while generating a second movement resistance Rm2 (>Rm1) that is higher than the first movement resistance Rm1.

[0070] • As a high-speed operation mode (first movement mode), an operation mode is adopted in which the arm is accelerated with a first acceleration A1 when moving the arm, and as a low-speed operation mode (second movement mode), an operation mode is adopted in which the arm is accelerated with a second acceleration A2 that is lower than the first acceleration A1 when moving the arm. Note that the first acceleration A1 and the second acceleration A2 may be constant, or they may be changed according to the external force detected by the external force detection unit 36, but the second acceleration A2 is an acceleration lower than the first acceleration A1 (A2 <A1)。

[0071] As random external force data, external forces detected by the force sensor 31 during direct teaching can be used. As random joint angle data, joint angles detected by the joint angle sensor 33 during direct teaching can be used. As joint torque data, torques detected by the torque sensor 32 during direct teaching can be used. In addition, as random external force data, external forces set by the user based on their direct teaching experience can be used. As random joint angle data, joint angles set by the user based on their direct teaching experience can be used.

[0072] The machine learning device 60 may consist of a PC (Personal Computer) or a server, etc., which are provided separately from the robot system 10.

[0073] The machine learning device 60 is not limited to the robot system 10 capable of direct teaching, but can also learn the position where an external force acts on the master robot in a master-slave robot system (master-slave robot system) where a slave robot operates according to the movements of a master robot. Furthermore, the machine learning device 60 can also learn the position where a user collides with robots 20, 120, 220, and 320 during their automated operation.

[0074] The relationship between the external force detected by the external force detection unit 36, the torque detected by the torque sensor 32, and the joint angle detected by the joint angle sensor 33 can be pre-registered as a template (predetermined relationship) based on tests, etc., and the position where the external force acts on the robots 20, 120, 220, 320 can be detected by pattern matching with the template.

[0075] Robots 20, 120, 220, and 320 are not limited to 6-axis vertical articulated robots; they may also be 5-axis vertical articulated robots or 7-axis vertical articulated robots.

[0076] <Regarding the group of inventions extracted from the above embodiments and modified examples> The following describes the features of the group of inventions extracted from the above embodiments and modified examples, while showing effects and other details as necessary.

[0077] (Feature 1) The arm has a plurality of links that are connected so as to be rotatable relative to each other. A torque sensor that detects the torque acting between the links connected to each other, It comprises an angle sensor that detects the angle between the links connected to each other, The robot system according to the first means, wherein the part detection unit detects whether the external force detected by the external force detection unit is applied to the first part or the second part of the arm, based on the external force detected by the external force detection unit, the torque detected by the torque sensor, the angle detected by the angle sensor, and a predetermined relationship thereof obtained in advance.

[0078] Even if the external force detected by the external force detection unit is the same, the torque acting between the interconnected links changes depending on the part to which the external force is applied and the angle between the interconnected links. Therefore, based on these pre-acquired relationships (trained AI model, template), the detected external force, detected torque, and detected angle, the part to which the external force is applied can be detected.

[0079] In this regard, according to the above configuration, the part detection unit can detect whether the external force detected by the external force detection unit was applied to the first part or the second part of the arm, based on the external force detected by the external force detection unit, the torque detected by the torque sensor, the angle detected by the angle sensor, and a predetermined relationship between these.

[0080] (Feature 2) The robot system according to feature 1, wherein a force sensor is provided on a predetermined link from the second to the tip among the plurality of links to detect the force and moment applied to the arm, and the external force detection unit detects the external force based on the force and moment detected by the force sensor.

[0081] With the above configuration, for example, the tip link can be designated as the second part, and the part of the links other than the tip that is closer to the tip than the force sensor can be designated as the first part, allowing the force and moment applied to the first and second parts to be detected by the force sensor. Furthermore, the force sensor can be used not only during direct teaching but also during the robot's autonomous operation to detect the force and moment acting on tools, etc., attached to the tip link.

[0082] Furthermore, based on Feature 1, the part detection unit can detect whether the external force detected by the external force detection unit was applied to the first part or the second part of the arm, based on the external force detected based on the force and moment detected by the force sensor, the torque detected by the torque sensor, the angle detected by the angle sensor, and a predetermined relationship therein.

[0083] (Feature 3) The robot system according to feature 1, wherein the external force detection unit detects the external force based on the torque detected by the torque sensor.

[0084] Generally, a robot arm has multiple links that are connected so as to be rotatable relative to each other, and the robot system is often equipped with a torque sensor that detects the torque acting between the interconnected links. In this respect, according to the above configuration, the external force detection unit can use the torque sensor provided in the robot system to detect the external force based on the torque detected by the torque sensor.

[0085] Furthermore, based on Feature 1, the part detection unit can detect whether the external force detected by the external force detection unit was applied to the first part or the second part of the arm, based on the external force detected based on the torque detected by the torque sensor, the torque detected by the torque sensor, the angle detected by the angle sensor, and a predetermined relationship between these.

[0086] (Feature 4) The robot system according to the first means, comprising a contact sensor for detecting a portion that has been contacted in the arm, wherein the portion detection unit detects, based on the portion detected by the contact sensor, whether the external force detected by the external force detection unit was applied to a first portion or a second portion on the tip side of the first portion in the arm.

[0087] According to the above configuration, based on the part detected by the contact sensor, it is possible to accurately detect whether the external force detected by the external force detection unit was applied to the first part or the second part.

[0088] (Feature 5) The arm has a plurality of links that are connected so as to be rotatable relative to each other. It includes a torque sensor that detects the torque acting between the links connected to each other, A force sensor is provided on the second and subsequent predetermined links from the tip of the plurality of links to detect the force and moment applied to the arm. The first part is the part of the arm that is closer to the proximal end than the force sensor, The second part is the part of the arm that is closer to the tip than the force sensor, The robot system according to the first means, wherein the part detection unit detects whether the external force detected by the external force detection unit is applied to the first part or the second part of the arm, based on the torque detected by the torque sensor, the force and moment detected by the force sensor, and a predetermined relationship therebetween thereof.

[0089] According to the above configuration, the portion of the arm closer to the tip than the force sensor is designated as the second portion, and the force and moment applied to the second portion can be detected by the force sensor. On the other hand, the force and moment applied to the first portion, which is the portion of the arm closer to the base than the force sensor, are not detected by the force sensor. Therefore, if a torque corresponding to the external force for movement is detected by the torque sensor, and no force and moment are detected by the force sensor, it can be assumed that the external force for movement has been applied to the first portion. Accordingly, the portion detection unit can detect whether the external force detected by the external force detection unit was applied to the first portion or the second portion of the arm, based on the torque detected by the torque sensor, the force and moment detected by the force sensor, and a predetermined relationship between them that has been acquired in advance.

[0090] (Feature 6) The robot system according to any one of the first to third means, wherein the first mode of movement is a mode of movement in which the arm is moved while generating a first movement resistance, and the second mode of movement is a mode of movement in which the arm is moved while generating a second movement resistance that is higher than the first movement resistance.

[0091] With the above configuration, if the user wants to fine-tune the position of the second part, they can apply a movement force to the second part, thereby moving the arm while receiving a second movement resistance that is higher than the first movement resistance. Also, if the user wants to move the arm a larger distance, they can apply a movement force to the first part, thereby moving the arm while receiving a first movement resistance that is lower than the second movement resistance. In this case, the user does not need to apply a special type of external force or be aware of the current movement mode, and can switch the movement resistance received when moving the arm through natural operation during direct teaching. [Explanation of Symbols]

[0092] 10...Robot system, 20...Robot, 21...First link, 22...Second link, 23...Third link, 24...Fourth link, 25...Fifth link, 26...Sixth link, 36...External force detection unit, 37...Contact part detection unit (part detection unit), 37a...Trained AI model, 50...Direct teaching control unit (control unit), 60...Machine learning device, 70...Data acquisition unit, 80...Learning unit, 80a...AI model, 120...Robot, 220...Robot, 320...Robot.

Claims

1. A robotic system capable of direct teaching, A robot with an arm, An external force detection unit for detecting an external force applied to the arm, A part detection unit detects whether the external force detected by the external force detection unit was applied to a first part of the arm or a second part located closer to the tip than the first part, When performing direct teaching, the control unit moves the arm in a first movement mode based on the external force detected by the external force detection unit when the first part is detected by the part detection unit, and moves the arm in a second movement mode that is less mobile than the first movement mode based on the external force detected by the external force detection unit when the second part is detected by the part detection unit. Equipped with, The first mode of movement is a mode of movement in which the arm is moved at a first speed, The robot system is characterized in that the second mode of movement is a mode in which the arm is moved at a second speed lower than the first speed.

2. A robotic system capable of direct teaching, A robot with an arm, An external force detection unit for detecting an external force applied to the arm, A part detection unit detects whether the external force detected by the external force detection unit was applied to a first part of the arm or a second part located closer to the tip than the first part, When performing direct teaching, the control unit moves the arm in a first movement mode based on the external force detected by the external force detection unit when the first part is detected by the part detection unit, and moves the arm in a second movement mode that is less mobile than the first movement mode based on the external force detected by the external force detection unit when the second part is detected by the part detection unit. Equipped with, The first mode of movement is a mode of movement in which the arm is moved while generating a first movement resistance, The robot system is characterized in that the second mode of movement is a mode of movement in which the arm is moved while generating a second movement resistance that is higher than the first movement resistance.

3. A robotic system capable of direct teaching, A robot with an arm, An external force detection unit for detecting an external force applied to the arm, A part detection unit detects whether the external force detected by the external force detection unit was applied to a first part of the arm or a second part located closer to the tip than the first part, When performing direct teaching, the control unit moves the arm in a first movement mode based on the external force detected by the external force detection unit when the first part is detected by the part detection unit, and moves the arm in a second movement mode that is less mobile than the first movement mode based on the external force detected by the external force detection unit when the second part is detected by the part detection unit. Equipped with, The first mode of movement is a mode of movement in which the arm is accelerated with a first acceleration, The robot system is characterized in that the second mode of movement is a mode of movement in which the arm is accelerated with a second acceleration lower than the first acceleration.

4. The arm has a plurality of links that are connected so as to be rotatable relative to each other. The first part is a link other than the tip among the plurality of links, The robot system according to any one of claims 1 to 3, wherein the second part is the leading link among the plurality of links.

5. The aforementioned multiple links include three or more links, A force sensor for detecting the force and moment applied to the arm is provided in the middle of the third link from the tip. The robot system according to claim 4, wherein the external force detection unit detects the external force based on the force and moment detected by the force sensor.

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