robot

Abstract

The present invention relates to a robot (1), the robot (1) comprising: a first component (3); a second component (4) which is driven to rotate relative to the first component (3) around a first axis (B); a third component (5) which is driven to rotate relative to the second component (4) around a second axis (C) which is spaced apart from the first axis (B); a single-axis torque detection unit (12) which detects only torque around at least one of the first axis (B) and the second axis (C); and a force sensor (11) which is arranged between the first component (3) and a surface (G) on which it is arranged, or any one of the first component (3), the second component (4), and the third component (5), and is capable of detecting a force in a direction intersecting both the first axis (B) and the second axis (C).

Description

Technical Field

[0001] The present invention relates to robots. Background Art

[0002] There is a known robot in which a force sensor is arranged on a base installed on the ground (for example, see Patent Document 1). There is also a known robot in which a torque sensor is provided on each joint axis (for example, see Patent Document 2).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 5980877

[0006] Patent Document 2: U.S. Patent Application Publication No. 2013 / 0255426 Summary of the invention

[0007] Problem that the invention aims to solve

[0008] The robot of Patent Document 1 detects the load applied to the robot's body or hands using force sensors installed on the base, so it can detect the contact between people, objects and various parts of the robot. However, it is sometimes difficult to detect contact methods in which the reaction forces cancel each other out, such as pinching between arms, contact between hands and the base, etc.

[0009] On the other hand, the robot of Patent Document 2 can also detect pinching between arms using a torque sensor, but it is difficult to detect the contact mode of the torque sensor in which torque does not act on all joint axes.

[0010] If the number of force sensors or torque sensors is increased, any contact method can be detected, but the structure becomes complicated and the cost increases. Therefore, a robot that can detect the necessary contact method without increasing the number of sensors is desired.

[0011] Solutions for solving problems

[0012] One embodiment of the present invention is a robot comprising: a first component; a second component, which is driven to rotate around a first axis relative to the first component; a third component, which is driven to rotate relative to the second component around a second axis separated from the first axis; a single-axis torque detection unit, which only detects torque around the first axis and around at least one of the second axis; and a force sensor, which is arranged between the first component and the surface on which it is arranged, the first component, the second component, and any one of the third component, and is capable of detecting force in a direction intersecting with both the first axis and the second axis. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a side view showing an example of a robot according to an embodiment of the present invention.

[0014] Figure 2 It means to use Figure 1 Side view of a contact pattern that the robot's single-axis torque sensor cannot detect.

[0015] Figure 3 Yes means Figure 1 A stereoscopic image of a robot.

[0016] Figure 4 It means to use Figure 1 Side view of a contact pattern that the robot cannot detect.

[0017] Figure 5 Yes means Figure 1 A side view of a modified example of the robot.

[0018] Figure 6 Yes means Figure 1 A side view of another variation of the robot.

[0019] Figure 7 Yes means Figure 1 A side view of another variation of the robot.

[0020] Description of Reference Numerals

[0021] 1.20: Robot

[0022] 2: Base

[0023] 3: Rotating body (first component)

[0024] 4: First arm (second part)

[0025] 5: Second arm (third component)

[0026] 6: Wrist unit

[0027] 7: First wrist component

[0028] 8: Second wrist component

[0029] 9: Third wrist component

[0030] 10: Single-axis torque sensor (third single-axis torque detection unit)

[0031] 11: Force sensor

[0032] 12: Single-axis torque sensor (single-axis torque detection unit, first single-axis torque detection unit)

[0033] 13: Single-axis torque sensor (second single-axis torque detection unit)

[0034] 14: Single-axis torque sensor (sixth single-axis torque detection unit)

[0035] 15: Single-axis torque sensor (fourth single-axis torque detection unit)

[0036] 16: Single-axis torque sensor (fifth single-axis torque detection unit)

[0037] A: J1 axis (third axis)

[0038] B: J2 axis (first axis)

[0039] C: J3 axis (second axis)

[0040] D: J4 axis (fourth axis)

[0041] E: J5 axis (fifth axis)

[0042] F: J6 axis (sixth axis)

[0043] G: Ground (installed surface) DETAILED DESCRIPTION

[0044] Hereinafter, a robot 1 according to an embodiment of the present invention will be described with reference to the drawings.

[0045] The robot 1 of the present embodiment includes: a base 2 installed on the ground (installation surface) G; and a revolving body (first component) 3 supported so as to be rotatable relative to the base 2 around a vertical J1 axis (third axis) A. Furthermore, the robot 1 includes: a first arm (second component) 4 supported so as to be rotatable relative to the revolving body 3 around a horizontal J2 axis (first axis) B; and a second arm (third component) 5 supported so as to be rotatable relative to the first arm 4 around a J3 axis (second axis) C parallel to the J2 axis B.

[0046] Furthermore, the robot 1 includes a three-axis wrist unit 6 at the front end of the second arm 5 .

[0047] The wrist unit 6 includes a first wrist element 7, which is rotatably supported on the second arm 5 around a J4 axis (fourth axis) D extending in the longitudinal direction of the second arm 5. In addition, the wrist unit 6 includes a second wrist element 8, which is rotatably supported on the first wrist element 7 around a J5 axis (fifth axis) E orthogonal to the J4 axis D. Furthermore, the wrist unit 6 includes a third wrist element 9, which is rotatably supported on the second wrist element 8 around a J6 axis (sixth axis) F, which is orthogonal to the J5 axis E and passes through the intersection of the J4 axis D and the J5 axis E.

[0048] Furthermore, the robot 1 of the present embodiment includes a uniaxial torque sensor (third uniaxial torque detection unit) 10 disposed between the floor G and the base 2, and the uniaxial torque sensor 10 detects only the torque around the J1 axis A. Furthermore, the robot 1 includes a force sensor 11 mounted on the rotating body 3, and the force sensor 11 detects the force in the horizontal uniaxial direction (the x direction fixed in the orthogonal coordinate system of the rotating body 3) along the plane that is orthogonal to the J2 axis B and includes the J1 axis A.

[0049] Furthermore, the robot 1 includes a uniaxial torque sensor (uniaxial torque detection unit, first uniaxial torque detection unit) 12 that detects only the torque around the J2 axis B between the rotary body 3 and the first arm 4. Furthermore, the robot 1 includes a uniaxial torque sensor (second uniaxial torque detection unit) 13 that detects only the torque around the J3 axis C between the first arm 4 and the second arm 5.

[0050] The torque detected by each uniaxial torque sensor 10, 12, 13 and the force detected by the force sensor 1 are sent to a control device (not shown), and when a torque or force exceeding a predetermined threshold is detected, the control device causes the robot 1 to stop or evade.

[0051] According to the robot 1 of the present embodiment configured in this way, when an object is clamped between the rotating body 3 and the first arm 4, the torque detected by the uniaxial torque sensor 12 that detects the torque around the J2 axis B increases to exceed the threshold value. Furthermore, when an object is clamped between the first arm 4 and the second arm 5, the torque detected by the uniaxial torque sensor 13 that detects the torque around the J3 axis C increases to exceed the threshold value. Thus, it is possible to detect that the object is clamped between the respective parts, and to perform a stopping action or an evasive action.

[0052] Moreover, even if the wrist unit 6 or the tool installed at the front end of the wrist unit 6 contacts the rotating body 3 or the first arm 4, the torque around the J2 axis B and the torque around the J3 axis C will increase, so the increased torque can be detected and a stopping action or an evasive action can be performed.

[0053] That is, according to this embodiment, compared with the conventional robot which arranges a six-axis force sensor between the floor G and the base 2 to detect contact with an object, it has the advantage of being able to detect contact caused by pinching between the arms 4 and 5 .

[0054] Next, if Figure 2 As shown, a case where the first arm 4 and the second arm 5 are arranged on a substantially straight line and, for example, an external force P acts on the wrist unit 6 in a direction along the straight line will be described.

[0055] In this case, since the torque detected by the two uniaxial torque sensors 12 and 13 does not increase sufficiently, it does not exceed the threshold and cannot detect contact. However, the force sensor 11 provided on the rotating body 3 detects the horizontal (x-direction) component of the force acting in the longitudinal direction of the first arm 4, that is, in the direction orthogonal to both the J2 axis B and the J3 axis C.

[0056] Therefore, according to this embodiment, compared with the conventional robot that arranges a torque sensor at each joint to detect contact with an object, there is an advantage that contact in which torque does not act on the torque sensor can also be detected by the force sensor 11.

[0057] Moreover, for example, Figure 3 As shown, when a lateral external force acts on the first arm 4, the second arm 5, or the wrist unit 6, the torque detected by the uniaxial torque sensor 10 disposed between the ground G and the base 2 increases to exceed a threshold value. Thus, the robot 1 can detect an object contacted from a lateral direction.

[0058] That is, according to the present embodiment, in addition to the three uniaxial torque sensors 10, 12, 13 that detect only the torque around the J1 axis A, the J2 axis B, and the J3 axis C, a single force sensor 11 is also configured, so that it is also possible to detect the clamping of an object and the contact that cannot be detected by the uniaxial torque sensors 10, 12, 13. Thus, there is an advantage that the robot 1 that detects any contact is configured at a low cost by a simple structure with a reduced number of sensors. In addition, since the force sensor 11 is configured on the rotating body 3, it is possible to detect the force acting on the robot 1 without relying on the action angle of the rotating body 3.

[0059] It should be noted that, in this embodiment, the force sensor 11 only detects the force in the x direction. Figure 4 As shown, when the first arm 4 and the second arm 5 extend in the direction along the J1 axis A, the force acting on the front end of the second arm 5 in the direction along the J1 axis A (z direction) cannot be detected.

[0060] When detecting the contact in the above manner, a sensor capable of detecting forces in the x-direction and the z-direction may be used as the force sensor 11. In addition, when a sensor capable of detecting forces in the x-direction and the y-direction is used as the force sensor 11, the uniaxial torque sensor 10 disposed between the floor G and the base 2 may not be provided. Furthermore, the force sensor 11 may be a sensor capable of detecting forces in the x-direction, the y-direction, and the z-direction.

[0061] Furthermore, in the present embodiment, the force sensor 11 is disposed on the rotating body 3, but instead, it may be disposed between the ground G and the base 2, or on any one of the base 2, the first arm 4, and the second arm 5. In particular, if Figure 5 As shown, by providing the force sensor 11 on the first arm 4, the x direction, which is the length direction of the first arm 4, can be detected. s The force in the direction perpendicular to the J2 axis B and the J3 axis C can be detected independently of the operation angle of the first arm 4.

[0062] That is, by providing the force sensor 11 on the first arm 4, even if Figure 4 In the contact mode shown, the direction of the force detected by the uniaxial force sensor 11 can be moved in accordance with the operating angle of the first arm 4 , thereby enabling detection with high accuracy.

[0063] Furthermore, in the present embodiment, the case where the rotary body 3 and the first arm 4 are not offset in the direction of the J2 axis line B is exemplified, but the present invention may also be applied to a case where they are offset.

[0064] Furthermore, in the present embodiment, the case where the torque around the J1 axis A to the J3 axis C is detected is described, but instead, the single-axis torque sensors 14, 15, and 16 for detecting the torque around the J4 axis D to the J6 axis F may be respectively configured. Figure 6 As shown, uniaxial torque sensors 10, 12, 13, 14, 15, and 16 for detecting torques of all axes around the J1 axis A to the J6 axis F may be respectively configured. In particular, by configuring a uniaxial torque sensor (fourth uniaxial torque detection unit) 15 for detecting torque around the J5 axis E, it is possible to detect pinching between the first wrist element 7 and the second wrist element 8, or between a tool (not shown) mounted on the wrist unit 6 and various parts of the robot 1.

[0065] Moreover, when an object is clamped between a tool (not shown) mounted on the third wrist element 9 and various parts of the robot 1, the clamping situation can be detected by using a single-axis torque sensor (fifth single-axis torque detection unit) 16 that detects the torque around the J6 axis F, or a single-axis torque sensor (sixth single-axis torque detection unit) 14 that detects the torque around the J4 axis D.

[0066] When detecting the torque around the J4 axis D to the J6 axis F, or detecting the torque around all the axes of the J1 axis A to the J6 axis F, the force sensor 11 may be mounted on the second arm 5. Thus, even if the force acting on the tip of the third wrist element 9 in the direction along the J4 axis D cannot be detected in the single-axis torque detection units 14, 15, and 16, the force acting in the direction along the J4 axis D can be detected by the force sensor 11 mounted on the second arm 5.

[0067] Furthermore, the force sensor 11 may be mounted on the wrist element 6. Thus, the force acting in the direction along the J4 axis D on the distal end side can be detected depending on the mounting position of the force sensor 11.

[0068] Furthermore, as the wrist unit 6, the first wrist element 7 may be supported on the second arm 5 at the front end of the second arm 5 so as to be rotatable relative to the second arm 5 around the fourth axis D, the second wrist element 8 may be supported relative to the first wrist element 7 so as to be rotatable around the fifth axis E orthogonal to the fourth axis D, and the third wrist element 9 may be supported relative to the second wrist element 8 so as to be rotatable around the sixth axis F orthogonal to the fifth axis E and parallel to the fourth axis D. In this case, the single-axis torque detection units 14, 15, 16 can detect only the torque around at least one of the fourth axis D, the fifth axis E, and the sixth axis F.

[0069] Moreover, as the wrist unit 6, the first wrist element 7 can also be supported on the second arm 5 at the front end of the second arm 5 in a manner that allows it to rotate around a fourth axis D that is orthogonal to the long axis of the second arm 5, the second wrist element 8 can be supported relative to the first wrist element 7 in a manner that allows it to rotate around a fifth axis E that is orthogonal to the fourth axis D, and the third wrist element 9 can be supported relative to the second wrist element 8 in a manner that allows it to rotate around a sixth axis F that is orthogonal to the fifth axis E and parallel to the fourth axis D.

[0070] Moreover, in the present embodiment, a vertical multi-joint robot 1 is illustrated, but a horizontal multi-joint robot may be used instead. In this case, a single-axis torque sensor (first single-axis torque detection unit) is arranged between a base (first component) and a first arm (second component) that can swing relative to the base around a vertical J1 axis (first axis). Moreover, a single-axis torque sensor (second single-axis torque detection unit) is arranged between the first arm and a second arm (third component) that can swing relative to the first arm around a J2 axis (second axis) parallel to the J1 axis. Moreover, as a single-axis torque sensor, at least one of the first single-axis torque detection unit and the second single-axis torque detection unit may be arranged.

[0071] Then, a force sensor capable of detecting a force in a direction along the first arm may be arranged at any position between the ground and the first arm.

[0072] Thus, in the sandwiched state between the base and the first arm, in the sandwiched state between the first arm and the second arm, and in the state where the first arm and the second arm are arranged in a straight line, the force applied in the direction along the straight line can be detected with high accuracy.

[0073] Furthermore, in the present embodiment, a uniaxial torque sensor is exemplified as the torque detection unit that detects torque, but instead, the torque may be estimated by detecting the current of the motor that drives each unit.

[0074] Furthermore, when an auxiliary encoder is provided, the torque can be estimated based on the angle information detected by the auxiliary encoder.

[0075] Furthermore, a six-axis multi-joint robot 1 is exemplified, but it can also be applied to Figure 7 The robot 20 of the seven-axis multi-articulated type shown in the figure. In this case, it is sufficient to configure single-axis torque sensors 10, 12, 13, and 22 for detecting torque around the J1 axis A1 to the J4 axis D1. Reference numeral 21 is a third arm, which is supported in a manner that allows rotation relative to the second arm 5 around the J4 axis D1 parallel to the J3 axis C1.

[0076] In this case, similar to the six-axis multi-articulated robot 1, there is a contact mode that cannot be detected by the single-axis torque sensors 10, 12, 13, and 22. Specifically, when the first arm 4, the second arm 5, and the third arm 21 extend in the direction of the J1 axis A, the single-axis torque sensors 10, 12, 13, and 22 cannot detect the force acting on the front end of the third arm 21 in the direction of the J1 axis A. Therefore, it is necessary to have a force sensor 11 that can detect forces in at least two directions including the direction along the J1 axis A. Thus, even in a contact mode that cannot be detected by the single-axis torque sensors 10, 12, 13, and 22, the direction of the force detected by the single-axis force sensor 11 can be moved in coordination with the movement angle of the first arm 4, thereby enabling detection with high accuracy.

[0077] In this case, the first wrist element 7 is supported by the third arm 21 in a manner rotatable around a J5 axis E1 extending in the longitudinal direction of the third arm 21. Furthermore, the second wrist element 8 is supported by the first wrist element 7 in a manner rotatable around a J6 axis F1 orthogonal to the J5 axis E1, and the third wrist element 9 is supported by the second wrist element 8 in a manner rotatable around a J7 axis H1 orthogonal to the J6 axis F1 and passing through the intersection of the J5 axis E1 and the J6 axis F1.

[0078] In addition, it can also be applied to a single-axis robot. In this case, the robot 1 as a single-axis robot includes: a base (first component) 2, which is set on the ground G; a first arm (second component) 4, which is supported in a manner that can rotate relative to the base 2 around a horizontal axis (first axis); a single-axis torque sensor 10, which detects torque around the horizontal axis; and a force sensor 11, which is set between the base 2 and the ground G. The force sensor 11 can also be set on the base 2 or the first arm 4.

[0079] Furthermore, although the robot 1 of the present embodiment is provided with three uniaxial torque sensors 10 , 12 , and 13 , it is also possible to provide at least one of the two uniaxial torque sensors 12 and 13 .

[0080] In the present embodiment, the J2 axis B as the first axis and the J3 axis C as the second axis are parallel to each other with a gap, but the two axes B and C may be arranged with a gap. For example, the two axes B and C may be arranged with a gap in an eccentric relationship.

Claims

1. A robot, characterized in that: have: first component; a second member rotatably driven relative to the first member about a first axis; a third member rotatably driven relative to the second member about a second axis spaced apart from the first axis; a single-axis torque detection unit that detects only the torque about at least one of the first axis and the second axis; a force sensor disposed between the first member and the surface to be installed, or in any one of the first member, the second member, and the third member, and capable of detecting a force in a direction intersecting both the first axis and the second axis; as well as Control device, The control device determines that an object is sandwiched between the first component and the second component and between the second component and the third component when the torque detected by the single-axis torque detection unit exceeds a predetermined threshold value, and determines that an object is in contact with the direction intersecting both the first axis and the second axis when the force detected by the force sensor exceeds a predetermined threshold value.

2. The robot according to claim 1, characterized in that: The single-axis torque detection unit is provided so as to be capable of detecting torque around the first axis and torque around the second axis.

3. The robot according to claim 1, characterized in that: The force sensor is fixed to the second component.

4. The robot according to any one of claims 1 to 3, characterized in that: The force sensor is capable of detecting force in a direction along the first axis.

5. The robot according to any one of claims 1 to 3, characterized in that: The robot comprises a base arranged on the installation surface. The first member is a rotating body supported relative to the base so as to be rotatable about a third axis orthogonal to the installation surface. The second member is a first arm supported relative to the rotary body so as to be rotatable about the first axis arranged in a plane orthogonal to the third axis. The third component is a second arm that is rotatable about the second axis that is parallel to the first axis.

6. The robot according to claim 5, characterized in that: A third uniaxial torque detection unit is provided at an arbitrary position from the installation surface to the rotary body, and the third uniaxial torque detection unit is capable of detecting only torque around the third axis line.

7. The robot according to claim 5, characterized in that: The robot has: a first wrist element supported at a front end of the second arm in a manner rotatable about a fourth axis; a second wrist element supported relative to the first wrist element so as to be rotatable about a fifth axis orthogonal to the fourth axis; as well as a third wrist element supported relative to the second wrist element so as to be rotatable about a sixth axis orthogonal to the fifth axis, The robot includes a single-axis torque detection unit capable of detecting only torque about at least one of the fourth axis, the fifth axis, and the sixth axis.

8. A robot, characterized in that: have: first component; a second member rotatably driven relative to the first member about a first axis; a first single-axis torque detection unit that detects only the torque around the first axis; a force sensor disposed between the first member and the surface to be installed, or in any one of the first member and the second member, and capable of detecting a force in a direction orthogonal to the first axis; as well as Control device, The control device determines that an object is sandwiched between the first component and the second component when the torque detected by the single-axis torque detection unit exceeds a predetermined threshold value, and determines that an object is in contact in a direction intersecting the first axis when the force detected by the force sensor exceeds a predetermined threshold value.

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