Control unit, driving device, and control method

Abstract

The invention provides a control unit, a driving device and a control method. The drive device includes a motor, a decelerator, and an object. The decelerator decelerates the rotational motion output from the motor. The object is operated by the rotational motion output from the decelerator. The control unit controls the motor according to a detection value of a sensor mounted on the speed reducer.

Description

Technical Field

[0001] The invention relates to a control unit, a driving device and a control method. Background Art

[0002] Conventionally, there is known a drive device having a motor and a speed reduction device for reducing the rotation of the motor (for example, Patent Document 1). In the drive device of Patent Document 1, the motor is controlled while correcting the expansion / contraction caused by the temperature change of the arm by a temperature sensor installed in an encoder of the motor.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2015-141583

[0004] However, in such a driving device, a speed reducer is disposed between the motor and the arm. Therefore, it is difficult for the temperature sensor attached to the motor to detect the temperature change of the arm with high accuracy. Summary of the invention

[0005] An object of the present invention is to provide a technology capable of controlling a motor in a driving device while detecting the state of an arm with high accuracy.

[0006] The first exemplary invention of the present application is a control unit, which is a control unit of a driving device, the driving device comprising: a motor; a reducer that reduces the speed of rotational motion output from the motor; and an object that moves by the rotational motion output from the reducer, wherein the control unit controls the motor based on the detection value of a sensor mounted on the reducer.

[0007] The second exemplary invention of the present application is a control unit, which is a control unit of a driving device, the driving device comprising: a plurality of motors; a plurality of reducers, which reduce the speed of rotational motion outputted from the plurality of motors respectively; and a plurality of objects, which are moved by the rotational motion outputted from the plurality of reducers respectively, wherein the control unit controls at least one of the plurality of motors according to the detection value of a sensor mounted on at least one of the plurality of reducers.

[0008] The third exemplary invention of the present application is a control method, which is a control method for a driving device, the driving device comprising: a motor; a reducer that reduces the speed of rotational motion output from the motor; and an object that moves by the rotational motion output from the reducer, wherein the motor is controlled based on a detection value of a sensor mounted on the reducer.

[0009] The fourth exemplary invention of the present application is a control method, which is a control method for a driving device, the driving device comprising: a plurality of motors; a plurality of reducers, which reduce the speed of rotational motion respectively output from the plurality of motors; and a plurality of objects, which are moved by the rotational motion respectively output from the plurality of reducers, wherein at least one of the plurality of motors is controlled based on the detection value of a sensor mounted on at least one of the plurality of reducers.

[0010] According to the exemplary first, second, third, and fourth inventions of the present application, the motor is controlled based on the detection value of the sensor mounted on the speed reducer. Thus, the motor can be controlled while the state of the arm is detected with high accuracy.

[0011] The above and other features, elements, steps, characteristics and advantages of the present invention will be more clearly understood from the following detailed description of preferred embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of the drive device.

[0013] Figure 2 This is a diagram conceptually showing the configuration of a motor, a speed reducer, an arm, and a control unit.

[0014] Figure 3 It is a longitudinal section view of the reducer.

[0015] Figure 4 It is a cross-sectional view of the reducer.

[0016] Figure 5 It is a partial longitudinal sectional view of the flexible gear near the sensor substrate.

[0017] Figure 6 is a top view of the sensor substrate.

[0018] Figure 7 This is a circuit diagram of a first bridge circuit of a first torque sensor.

[0019] Figure 8 This is a circuit diagram of a second bridge circuit of the second torque sensor.

[0020] Fig. 9 This is a circuit diagram of the third bridge circuit of the angle sensor.

[0021] Fig.10 This is a circuit diagram of the 4th bridge circuit of the angle sensor.

[0022] Fig.11It is a graph showing the time change of the measurement value of the third voltmeter of the third bridge circuit and the measurement value of the fourth voltmeter of the fourth bridge circuit.

[0023] Fig.12 This is a circuit diagram of the fifth bridge circuit of the first thrust sensor.

[0024] Fig.13 This is a circuit diagram of the sixth bridge circuit of the second thrust sensor.

[0025] Fig.14 It is a flowchart showing the flow of control by the control unit.

[0026] Fig.15 This is a schematic diagram of a driving device according to a first modified example. DETAILED DESCRIPTION

[0027] Hereinafter, exemplary embodiments of the present application will be described with reference to the drawings.

[0028] <1. Structure of the drive unit>

[0029] Figure 1 1 is a schematic diagram of a drive device 100 having a control unit 2 according to an embodiment. The drive device 100 is, for example, a so-called industrial robot that performs operations such as transporting, processing, and assembling parts in a production line of industrial products. Figure 1 As shown, the driving device 100 includes a motor 103, a speed reducer 1, an arm 102, and a control unit 2. In addition, the driving device 100 of the present embodiment further includes a base frame 101.

[0030] The arm 102 is supported so as to be rotatable relative to the base frame 101. The motor 103 and the reducer 1 are assembled at the joint between the base frame 101 and the arm 102. When a driving current is supplied to the motor 103, a rotational motion is output from the motor 103. The reducer 1 decelerates the rotational motion output from the motor 103 and transmits it to the arm 102. Thus, the arm 102 rotates at a decelerated speed relative to the base frame 101. That is, the arm 102 is an object that moves by the rotational motion output from the reducer 1.

[0031] The control unit 2 is a device for controlling the operation of the driving device 100. The control unit 2 is composed of a computer or a circuit. Figure 1 As shown, the control unit 2 includes a processor 201 such as a CPU, a memory 202 such as a RAM, and a storage unit 203 such as a hard disk drive. The storage unit 203 stores a program P for controlling the operation of the drive device 100. The control unit 2 operates according to the program P.

[0032] Figure 21 is a diagram conceptually showing the structure of the motor 103, the speed reducer 1, the arm 102, and the control unit 2. Figure 2 As shown, the reducer 1 has a sensor 50 capable of detecting the state of the arm 102. The control unit 2 is electrically connected to the sensor 50 and the motor 103. The control unit 2 controls the motor 103 based on the detection value of the sensor 50 mounted on the reducer 1. As a result, the motor 103 can be controlled based on the sensor 50 arranged at a position closer to the arm 102 than the motor 103. Therefore, the motor 103 can be controlled while the state of the arm 102 is detected with high accuracy. As a result, the arm 102 can be operated with high accuracy.

[0033] The detailed structure of the sensor 50 will be described later.

[0034] <2. Structure of the reducer>

[0035] Next, the detailed structure of the speed reducer 1 will be described.

[0036] In addition, hereinafter, the direction parallel to the central axis 9 of the reducer 1 is referred to as the "axial direction", the direction perpendicular to the central axis 9 of the reducer 1 is referred to as the "radial direction", and the direction along the arc centered on the central axis 9 of the reducer 1 is referred to as the "circumferential direction". However, the above-mentioned "parallel direction" also includes a substantially parallel direction. In addition, the above-mentioned "vertical direction" also includes a substantially vertical direction.

[0037] Figure 3 It is a longitudinal sectional view of the speed reducer 1 which concerns on one embodiment. Figure 4 is from Figure 2 The cross-sectional view of the reducer 1 observed from the AA position. In order to avoid the complexity of the figure, Figure 4 In the figure, hatching indicating cross sections is omitted.

[0038] The reducer 1 is a wave gear reducer. The reducer 1 reduces the rotational motion of the first speed output from the motor 103 to a second speed slower than the first speed. Figure 3 and Figure 4 As shown, the speed reducer 1 has an input shaft 10 , an internal gear 20 , a flexible gear 30 , and a wave generator 40 .

[0039] The input shaft 10 is a component that rotates at a first speed before deceleration. The input shaft 10 is connected to the output shaft of the motor 103. The input shaft 10 extends axially along the central axis 9. The input shaft 10 of the present embodiment is cylindrical with the central axis 9 as the center. The input shaft 10 penetrates the reducer 1 in the axial direction. In addition, the input shaft 10 may also be the same component as the output shaft of the motor 103.

[0040] The internal gear 20 is a gear that rotates at a second speed slower than the first speed as the input shaft 10 rotates. The internal gear 20 is fixed to the arm 102. The internal gear 20 is arranged radially outside the external teeth 32 described later. The rigidity of the internal gear 20 is sufficiently higher than the rigidity of the body 31 of the flexible gear 30 described later.

[0041] The internal gear 20 is annular centered on the central axis 9. The internal gear 20 has a plurality of internal teeth 21. The plurality of internal teeth 21 protrude radially inward from the inner circumferential surface of the internal gear 20. The plurality of internal teeth 21 are arranged on the inner circumferential surface of the internal gear 20 at a constant pitch in the circumferential direction.

[0042] The flexible gear 30 is a ring-shaped gear that can bend and deform. The flexible gear 30 is fixed to the base frame 101. Figure 3 and Figure 4 As shown, the flexible gear 30 has a body portion 31 , a plurality of external teeth 32 , a diaphragm portion 33 , and a thick wall portion 34 .

[0043] The body 31 is a cylindrical portion centered on the central axis 9. One axial end of the body 31 is connected to the diaphragm 33. The body 31 extends from the radial inner end of the diaphragm 33 toward the other axial side. The end of the body 31 on the other axial side is located radially outside the wave generator 40 and radially inside the internal gear 20. The body 31 has flexibility and can be bent and deformed in the radial direction.

[0044] The plurality of external teeth 32 protrude radially outward from the radial outer side of the body 31. The plurality of external teeth 32 are arranged on the radial outer side of the other axial end of the body 31. The plurality of external teeth 32 are arranged at a constant pitch in the circumferential direction. A portion of the plurality of external teeth 32 meshes with a portion of the plurality of internal teeth 21 mentioned above. The number of internal teeth 21 of the internal gear 20 is slightly different from the number of external teeth 32 of the flexible gear 30.

[0045] The diaphragm portion 33 surrounds the central axis 9 and extends in a direction intersecting the central axis 9. The diaphragm portion 33 preferably extends along a plane perpendicular to the central axis 9. The diaphragm portion 33 extends from one axial end of the body portion 31 toward the radial outer side. In addition, the diaphragm portion 33 is annular and surrounds the central axis 9. The diaphragm portion 33 is thin-walled and can be slightly deformed.

[0046] The thick portion 34 is an annular portion located radially outside the diaphragm portion 33. The axial thickness of the thick portion 34 is thicker than the axial thickness of the diaphragm portion 33. The thick portion 34 is fixed to the base frame 101 directly or via another member.

[0047] The wave generator 40 is a mechanism for causing the flexible gear 30 to generate periodic flexural deformation. The wave generator 40 is arranged on the radial inner side of the external teeth 32. The wave generator 40 has a cam 41 and a flexible bearing 42. In the present embodiment, the input shaft 10 and the cam 41 are formed by one component. However, the cam 41 may also be a component different from the input shaft 10. In this case, it is sufficient to fix the cam 41 relative to the input shaft 10. The cam 41 is a component that imparts displacement to the flexible gear 30 with a period of 180°. The radial outer side surface of the cam 41 is an ellipse centered on the central axis 9.

[0048] The flexible bearing 42 is a bearing capable of flexural deformation and is disposed between the radially outer side surface of the cam 41 and the radially inner side surface of the body portion 31 of the flexible gear 30 .

[0049] The inner ring of the flexible bearing 42 contacts the radial outer side of the cam 41. The outer ring of the flexible bearing 42 contacts the radial inner side of the body 31. Therefore, the body 31 is deformed into an elliptical shape along the radial outer side of the cam 41. As a result, the outer teeth 32 of the flexible gear 30 mesh with the inner teeth 21 of the internal gear 20 at two locations corresponding to the ends of the major axis of the ellipse. At other locations in the circumferential direction, the outer teeth 32 and the inner teeth 21 do not mesh.

[0050] When the motor 103 is driven, the cam 41 rotates together with the input shaft 10 at the first speed around the central axis 9. As a result, the major axis of the above-mentioned ellipse of the flexible gear 30 also rotates at the first speed. As a result, the meshing position of the external teeth 32 and the internal teeth 21 also changes in the circumferential direction at the first speed. In addition, as described above, the number of internal teeth 21 of the internal gear 20 is slightly different from the number of external teeth 32 of the flexible gear 30. Due to the difference in the number of teeth, the meshing position of the external teeth 32 and the internal teeth 21 changes slightly in the circumferential direction every time the cam 41 rotates one circle. As a result, the internal gear 20 rotates at a second speed that is slower than the first speed around the central axis 9 relative to the flexible gear 30.

[0051] <3. About sensors>

[0052] <3-1. Sensor structure>

[0053] The reducer 1 has a sensor 50. Figure 3 As shown, the sensor 50 includes a sensor substrate 51 . The sensor substrate 51 is fixed to the surface of the diaphragm portion 33 .

[0054] Figure 5 It is a partial longitudinal sectional view of the flexible spline 30 in the vicinity of the sensor substrate 51 . Figure 6 is a top view of the sensor substrate 51. Figure 5 As shown, the sensor substrate 51 has an insulating layer 511 and a conductive layer 512 .

[0055] The insulating layer 511 is flexibly deformable. The insulating layer 511 extends in a direction intersecting the central axis 9. In addition, the insulating layer 511 is in a ring shape centered on the central axis 9. The insulating layer 511 is composed of a resin or an inorganic insulating material as an insulator. The insulating layer 511 is arranged on the surface of the diaphragm portion 33. The conductor layer 512 is formed on the surface of the insulating layer 511. A metal serving as a conductor is used as a material of the conductor layer 512. For example, a copper alloy, a chromium alloy, or copper is used as a material of the conductor layer 512.

[0056] The conductor layer 512 includes a torque sensor 60, an angle sensor 70, a thrust sensor 80, and a temperature sensor 90. The torque sensor 60, the angle sensor 70, and the thrust sensor 80 are each composed of a strain gauge. That is, the sensor 50 includes a strain gauge mounted on a gear of the reducer 1. Thus, as described later, various sensors can be composed of strain gauges. In addition, Figure 3 As shown, the sensor 50 has a signal processing circuit 52. The signal processing circuit 52 is electrically connected to the torque sensor 60, the angle sensor 70, the thrust sensor 80, and the temperature sensor 90.

[0057] <3-2. Torque sensor>

[0058] The torque sensor 60 is a sensor for detecting the torque applied to the diaphragm portion 33 of the flexible gear 30. That is, the torque sensor 60 is a sensor whose output signal changes according to the torque applied to the flexible gear 30. Figure 6 As shown in FIG. 1 , the torque sensor 60 of the present embodiment includes a first torque sensor 61 and a second torque sensor 62 . The second torque sensor 62 is arranged radially outward of the first torque sensor 61 .

[0059] The first torque sensor 61 has four strain gauges Ra, Rb, Rc, and Rd. Two strain gauges Ra and Rb of the four strain gauges Ra, Rb, Rc, and Rd are arranged at intervals in the circumferential direction. The two strain gauges Ra and Rb are respectively arranged in a semicircular arc shape within a range of about 180° centered on the central axis 9. The radial distance from the central axis 9 to the strain gauge Ra is substantially the same as the radial distance from the central axis 9 to the strain gauge Rb.

[0060] The other two strain gauges Rc and Rd of the four strain gauges Ra, Rb, Rc, and Rd are arranged radially outward from the above two strain gauges Ra and Rb. The two strain gauges Rc and Rd are arranged at intervals in the circumferential direction. The two strain gauges Rc and Rd are respectively arranged in a semicircular arc shape within a range of about 180° centered on the central axis 9. The radial distance from the central axis 9 to the strain gauge Rc is approximately the same as the radial distance from the central axis 9 to the strain gauge Rd.

[0061] Furthermore, the two strain gauges Ra and Rc are arranged concentrically and line-symmetrically with the two strain gauges Rb and Rd.

[0062] like Figure 6 As shown, the strain gauges Ra, Rb, Rc, and Rd are patterns extending in the circumferential direction while being bent in a zigzag shape. Each strain gauge Ra, Rb, Rc, and Rd has a plurality of resistance lines r1 arranged in the circumferential direction and substantially parallel to each other. Each resistance line r1 extends in a direction having both radial and circumferential components.

[0063] The resistance wire r1 of the strain gauges Ra and Rd is inclined toward one side of the circumferential direction relative to the radial direction. The resistance wire r1 of the strain gauges Rb and Rc is inclined toward the other side of the circumferential direction relative to the radial direction. The inclination angle of the resistance wire r1 relative to the radial direction is, for example, 45°. The ends of the resistance wires r1 adjacent to each other in the circumferential direction are alternately connected to each other on the radial inner side or the radial outer side. Thus, the plurality of resistance wires r1 are connected in series as a whole.

[0064] The second torque sensor 62 has four strain gauges Re, Rf, Rg, and Rh. Two of the four strain gauges Re, Rf, Rg, and Rh are arranged at intervals in the circumferential direction. The two strain gauges Re and Rf are respectively arranged in a semicircular arc shape within a range of about 180° centered on the central axis 9. The radial distance from the central axis 9 to the strain gauge Re is substantially the same as the radial distance from the central axis 9 to the strain gauge Rf.

[0065] The other two strain gauges Rg and Rh of the four strain gauges Re, Rf, Rg and Rh are arranged radially outwardly of the two strain gauges Re and Rf. The two strain gauges Rg and Rh are arranged at intervals in the circumferential direction. The two strain gauges Rg and Rh are respectively arranged in a semicircular arc shape within a range of about 180° centered on the central axis 9. The radial distance from the central axis 9 to the strain gauge Rg is approximately the same as the radial distance from the central axis 9 to the strain gauge Rh.

[0066] Furthermore, the two strain gauges Re and Rg are arranged concentrically and line-symmetrically with the two strain gauges Rf and Rh.

[0067] like Figure 6 As shown, the strain gauges Re, Rf, Rg, and Rh are patterns that are bent in a zigzag shape while extending in the circumferential direction. Each strain gauge Re, Rf, Rg, and Rh has a plurality of resistance lines r2 that are arranged in the circumferential direction and are substantially parallel to each other. Each resistance line r2 extends in a direction having both radial and circumferential components.

[0068] The resistance wire r2 of the strain gauges Re and Rh is inclined toward one side of the circumferential direction relative to the radial direction. The resistance wire r2 of the strain gauges Rf and Rg is inclined toward the other side of the circumferential direction relative to the radial direction. The inclination angle of the resistance wire r2 relative to the radial direction is, for example, 45°. The ends of the resistance wires r2 adjacent to each other in the circumferential direction are alternately connected to each other on the radial inner side or the radial outer side. Thus, the plurality of resistance wires r2 are connected in series as a whole.

[0069] Figure 7 is a circuit diagram of the first bridge circuit C1 including the four strain gauges Ra, Rb, Rc, and Rd of the first torque sensor 61. Figure 7 As shown, the four strain gauges Ra, Rb, Rc, and Rd are connected to each other to form a first bridge circuit C1.

[0070] The strain gauge Ra and the strain gauge Rb are connected in series. The strain gauge Rc and the strain gauge Rd are connected in series. Moreover, between the + pole and the - pole of the power supply voltage, the column of the two strain gauges Ra and Rb is connected in parallel with the column of the two strain gauges Rc and Rd. In addition, the first voltmeter V1 is connected between the middle point M11 of the two strain gauges Ra and Rb and the middle point M12 of the two strain gauges Rc and Rd.

[0071] The resistance value of each resistance wire r1 changes according to the torque applied to the area where the resistance wire r1 is configured. For example, when a torque is applied to the diaphragm portion 33 toward one side in the circumferential direction with the central axis 9 as the center, the resistance value of each resistance wire r1 of the two strain gauges Ra and Rd increases, and the resistance value of each resistance wire r1 of the other two strain gauges Rb and Rc decreases. On the other hand, when a torque is applied to the diaphragm portion 33 toward the other side in the circumferential direction with the central axis 9 as the center, the resistance value of each resistance wire r1 of the two strain gauges Ra and Rd decreases, and the resistance value of each resistance wire r1 of the other two strain gauges Rb and Rc increases. In this way, the two strain gauges Ra and Rd and the other two strain gauges Rb and Rc show resistance value changes in opposite directions to each other with respect to the torque.

[0072] When the resistance values ​​of the four strain gauges Ra, Rb, Rc, and Rd change, the potential difference between the middle point M11 of the two strain gauges Ra and Rb and the middle point M12 of the two strain gauges Rc and Rd changes, so the measurement value of the first voltmeter V1 also changes. The signal processing circuit 52 detects the direction and magnitude of the torque applied to the diaphragm portion 33 based on the measurement value of the first voltmeter V1.

[0073] Figure 8 : is a circuit diagram of the second bridge circuit C2 including the four strain gauges Re, Rf, Rg, and Rh of the second torque sensor 62. Figure 8 As shown, the four strain gauges Re, Rf, Rg, and Rh are connected to each other to form a second bridge circuit C2.

[0074] The strain gauges Re and Rf are connected in series. The strain gauges Rg and Rh are connected in series. Moreover, between the + pole and the - pole of the power supply voltage, the column of the two strain gauges Re and Rf is connected in parallel with the column of the two strain gauges Rg and Rh. In addition, the second voltmeter V2 is connected between the middle point M21 of the two strain gauges Re and Rf and the middle point M22 of the two strain gauges Rg and Rh.

[0075] The resistance value of each resistance wire r2 changes according to the torque applied to the area where the resistance wire r2 is configured. For example, when a torque is applied to the diaphragm portion 33 toward one side of the circumference with the central axis 9 as the center, the resistance value of each resistance wire r2 of the two strain gauges Re and Rh increases, and the resistance value of each resistance wire r2 of the other two strain gauges Rf and Rg decreases. On the other hand, when a torque is applied to the diaphragm portion 33 toward the other side of the circumference with the central axis 9 as the center, the resistance value of each resistance wire r2 of the two strain gauges Re and Rh decreases, and the resistance value of each resistance wire r2 of the other two strain gauges Rf and Rg increases. In this way, the two strain gauges Re and Rh and the other two strain gauges Rf and Rg show resistance value changes in opposite directions relative to the torque.

[0076] When the resistance values ​​of the four strain gauges Re, Rf, Rg, and Rh change, the potential difference between the middle point M21 of the two strain gauges Re and Rf and the middle point M22 of the two strain gauges Rg and Rh changes, so the measurement value of the second voltmeter V2 also changes. The signal processing circuit 52 detects the direction and magnitude of the torque applied to the diaphragm portion 33 based on the measurement value of the second voltmeter V2.

[0077] In addition, the speed reducer 1 of the present embodiment has two torque sensors 61 and 62. The signal processing circuit 52 uses any one of the output signals of the two torque sensors 61 and 62 as the output signal of the torque sensor 60. By having two torque sensors 61 and 62, even if an abnormality occurs in one of the torque sensors, the torque can be detected by the other torque sensor. In addition, when an abnormality occurs in one of the torque sensors, the abnormality can be detected.

[0078] <3-3. Angle sensor>

[0079] The angle sensor 70 is a sensor for detecting the rotation angle of the rotational motion input to the reducer 1. Figure 6 As shown, the angle sensor 70 includes eight strain gauges Ri, Rj, Rk, Rl, Rm, Rn, Ro, and Rp. The eight strain gauges Ri, Rj, Rk, Rl, Rm, Rn, Ro, and Rp are arranged at intervals in the circumferential direction.

[0080] The eight strain gauges Ri, Rj, Rk, Rl, Rm, Rn, Ro, and Rp are each formed by one conductive wire. Each strain gauge Ri, Rj, Rk, Rl, Rm, Rn, Ro, and Rp has a resistance wire extending in an arc shape along the circumferential direction. However, in each strain gauge Ri, Rj, Rk, Rl, Rm, Rn, Ro, and Rp, the resistance wire extending in the circumferential direction may be repeatedly arranged in the radial direction. In addition, the resistance wire of each strain gauge Ri, Rj, Rk, Rl, Rm, Rn, Ro, and Rp may also extend in the radial direction. In addition, in each strain gauge Ri, Rj, Rk, Rl, Rm, Rn, Ro, and Rp, the resistance wire extending in the radial direction may be repeatedly arranged in the circumferential direction.

[0081] Four strain gauges Ri, Rk, Rm, and Ro that are not adjacent to each other among the eight strain gauges Ri, Rj, Rk, Rl, Rm, Rn, Ro, and Rp are connected to each other to form a third bridge circuit C3. Fig. 9 This is the circuit diagram of the third bridge circuit C3. Fig. 9 As shown, the strain gauge Ri and the strain gauge Rk are connected in series in sequence. The strain gauge Ro and the strain gauge Rm are connected in series in sequence. Moreover, between the + pole and the - pole of the power supply voltage, the column of the two strain gauges Ri and Rk is connected in parallel with the column of the two strain gauges Ro and Rm. In addition, a third voltmeter V3 is connected between the middle point M31 of the two strain gauges Ri and Rk and the middle point M32 of the two strain gauges Ro and Rm.

[0082] The remaining four strain gauges Rj, Rl, Rn, and Rp of the eight strain gauges Ri, Rj, Rk, Rl, Rm, Rn, Ro, and Rp are connected to each other to form a fourth bridge circuit C4. Fig.10 This is the circuit diagram of the 4th bridge circuit C4. Fig.10 As shown, the strain gauge Rp and the strain gauge Rn are connected in series in sequence. The strain gauge Rj and the strain gauge Rl are connected in series in sequence. Moreover, between the + pole and the - pole of the power supply voltage, the column of the two strain gauges Rp and Rn is connected in parallel with the column of the two strain gauges Rj and Rl. In addition, the fourth voltmeter V4 is connected between the middle point M41 of the two strain gauges Rp and Rn and the middle point M42 of the two strain gauges Rj and Rl.

[0083] When the reducer 1 is driven, a portion extending in the circumferential direction (hereinafter referred to as an "extension portion") and a portion contracting in the circumferential direction (hereinafter referred to as a "contraction portion") are generated in the diaphragm portion 33 of the flexible gear 30. Specifically, two extension portions and two contraction portions are generated alternately in the circumferential direction. That is, the extension portion and the contraction portion are generated alternately at intervals of 90° in the circumferential direction with the central axis 9 as the center. Moreover, the portion where these extension portions and contraction portions are generated rotates at the above-mentioned first rotation speed.

[0084] The resistance values ​​of the eight strain gauges Ri, Rj, Rk, Rl, Rm, Rn, Ro, and Rp change according to the expansion and contraction of the diaphragm 33 in the circumferential direction. For example, when the above-mentioned extension portion overlaps with a certain strain gauge, the resistance value of the strain gauge increases. On the other hand, when the above-mentioned contraction portion overlaps with a certain strain gauge, the resistance value of the strain gauge decreases.

[0085] exist Figure 6 In the example of , when the contraction portion overlaps with the strain gauges Ri and Rm, the extension portion overlaps with the strain gauges Rk and Ro. In addition, when the extension portion overlaps with the strain gauges Ri and Rm, the contraction portion overlaps with the strain gauges Rk and Ro. Therefore, in the third bridge circuit C3, the strain gauges Ri and Rm and the strain gauges Rk and Ro show opposite resistance value changes.

[0086] In addition, Figure 6 In the example of , when the contraction portion overlaps with the strain gauges Rp and Rl, the extension portion overlaps with the strain gauges Rn and Rj. In addition, when the extension portion overlaps with the strain gauges Rp and Rl, the contraction portion overlaps with the strain gauges Rn and Rj. Therefore, in the fourth bridge circuit C4, the strain gauges Rp and Rl and the strain gauges Rn and Rj show opposite resistance value changes.

[0087] Fig.11 It is a graph showing the time changes of the measurement value v3 of the third voltmeter V3 of the third bridge circuit C3 and the measurement value v4 of the fourth voltmeter V4 of the fourth bridge circuit C4. Fig.11 The horizontal axis of the graph represents time. Fig.11 The vertical axis of the curve graph represents the voltage value. When the reducer 1 is driven, Fig.11 As shown, the third voltmeter V3 and the fourth voltmeter V4 output periodically changing sinusoidal measurement values ​​v3 and v4, respectively. The period T of the measurement values ​​v3 and v4 is equivalent to 1 / 2 times the period of the first rotation speed mentioned above. In addition, the direction of the input rotational motion can be determined based on whether the phase of the measurement value v4 of the fourth voltmeter V4 is ahead of the phase of the measurement value v3 of the third voltmeter V3 by 1 / 8 of the first rotation speed (1 / 4 of the measurement values ​​v3 and v4) or is behind by 1 / 8 of the first rotation speed (1 / 4 of the measurement values ​​v3 and v4).

[0088] The signal processing circuit 52 detects the rotation angle of the rotational motion input to the speed reducer 1 based on the measurement value v3 of the third voltmeter V3 and the measurement value v4 of the fourth voltmeter V4. Specifically, the signal processing circuit 52 stores a function table that associates the combination of the measurement value v3 of the third voltmeter V3 and the measurement value v4 of the fourth voltmeter V4 with the rotation angle. The signal processing circuit 52 outputs the rotation angle by inputting the measurement values ​​v3 and v4 into the function table.

[0089] When the reducer 1 is driven, the flexible gear 30 is periodically flexed and deformed. Therefore, the output signal of the first torque sensor 61 and the output signal of the second torque sensor 62 include a component reflecting the torque to be measured and an error component (fluctuation error) caused by the periodic flexure deformation of the flexible gear 30. The fluctuation error changes in a sine wave shape according to the rotation angle of the rotation motion input to the reducer 1.

[0090] Therefore, the signal processing circuit 52 calculates the above-mentioned fluctuation error based on the rotation angle detected by the angle sensor 70. Then, the calculated fluctuation error is used to correct the output signals of the first torque sensor 61 and the second torque sensor 62. Specifically, the signal processing circuit 52 increases or decreases the output signals of the first torque sensor 61 and the second torque sensor 62 in the direction of eliminating the fluctuation error. As a result, the signal processing circuit 52 can output the torque applied to the flexible gear 30 with higher accuracy.

[0091] In addition, the signal processing circuit 52 may not calculate the above-mentioned rotation angle, but may multiply the respective measured values ​​v3 and v4 of the third voltmeter V3 and the fourth voltmeter V4 by a predetermined coefficient to synthesize the output signals of the first torque sensor 61 and the second torque sensor 62. In this way, the processing load caused by the calculation of the rotation angle can be reduced. Therefore, the calculation speed of the signal processing circuit 52 can be improved.

[0092] <3-4. Thrust sensor>

[0093] The thrust sensor 80 is a sensor for detecting the thrust applied to the flexible gear 30. That is, the thrust sensor 80 is a sensor whose output signal changes according to the thrust applied to the flexible gear 30. The thrust refers to the axial force. Figure 6 As shown, the thrust sensor 80 of the present embodiment includes a first thrust sensor 81 and a second thrust sensor 82 .

[0094] The first thrust sensor 81 has four strain gauges Rq, Rr, Rs, and Rt. Two of the four strain gauges Rq, Rr, Rs, and Rt are arranged radially outside the torque sensor 60. That is, the two strain gauges Rq, Rr are preferably arranged at the radial outer end of the diaphragm portion 33. In addition, the two strain gauges Rq, Rr are arranged at intervals in the circumferential direction. The two strain gauges Rq, Rr are respectively arranged in a semicircular arc shape within a range of about 180° centered on the central axis 9. The radial distance from the central axis 9 to the strain gauge Rq is approximately the same as the radial distance from the central axis 9 to the strain gauge Rr.

[0095] The other two strain gauges Rs and Rt of the four strain gauges Rq, Rr, Rs and Rt are arranged on the radial inner side of the torque sensor 60. That is, the two strain gauges Rs and Rt are preferably arranged at the radial inner end of the diaphragm portion 33. In addition, the two strain gauges Rs and Rt are arranged at intervals in the circumferential direction. The two strain gauges Rs and Rt are respectively arranged in a semicircular arc shape within a range of about 180° centered on the central axis 9. The radial distance from the central axis 9 to the strain gauge Rs is approximately the same as the radial distance from the central axis 9 to the strain gauge Rt.

[0096] That is, the two strain gauges Rq and Rr and the two strain gauges Rs and Rt are arranged at intervals in the radial direction.

[0097] like Figure 6 As shown, the strain gauges Rq, Rr, Rs, and Rt are patterns that are bent in a zigzag shape while extending in the circumferential direction. Each strain gauge Rq, Rr, Rs, and Rt has a plurality of resistance wires r3 that are arranged in the circumferential direction and are substantially parallel to each other. Each resistance wire r3 extends in the radial direction. The ends of the resistance wires r3 adjacent to each other in the circumferential direction are alternately connected to each other radially inside or radially outside. Thus, the plurality of resistance wires r3 are connected in series as a whole.

[0098] The second thrust sensor 82 has four strain gauges Ru, Rv, Rw, and Rx. Two strain gauges Ru and Rv of the four strain gauges Ru, Rv, Rw, and Rx are arranged radially outside the above-mentioned strain gauges Rq and Rr. In addition, the two strain gauges Ru and Rv are arranged at intervals in the circumferential direction. The two strain gauges Ru and Rv are respectively arranged in a semicircular arc shape within a range of about 180° centered on the central axis 9. The radial distance from the central axis 9 to the strain gauge Ru is approximately the same as the radial distance from the central axis 9 to the strain gauge Rv.

[0099] The other two strain gauges Rw and Rx of the four strain gauges Ru, Rv, Rw and Rx are arranged radially inside the strain gauges Rs and Rt. In addition, the two strain gauges Rw and Rx are arranged at intervals in the circumferential direction. The two strain gauges Rw and Rx are respectively arranged in a semicircular arc shape within a range of about 180° centered on the central axis 9. The radial distance from the central axis 9 to the strain gauge Rw is approximately the same as the radial distance from the central axis 9 to the strain gauge Rx.

[0100] That is, the two strain gauges Ru and Rv and the two strain gauges Rw and Rx are arranged at intervals in the radial direction.

[0101] like Figure 6As shown, the strain gauges Ru, Rv, Rw, and Rx are patterns that are bent in a zigzag shape while extending in the circumferential direction. Each strain gauge Ru, Rv, Rw, and Rx has a plurality of resistor wires r4 that are arranged in the circumferential direction and are substantially parallel to each other. Each resistor wire r4 extends in the radial direction. The ends of the resistor wires r4 that are adjacent in the circumferential direction are alternately connected to each other radially inside or radially outside. Thus, the plurality of resistor wires r4 are connected in series as a whole.

[0102] Fig.12 is a circuit diagram of the fifth bridge circuit C5 including the four strain gauges Rq, Rr, Rs, and Rt of the first thrust sensor 81. Fig.12 As shown, the four strain gauges Rq, Rr, Rs, and Rt are interconnected to form a fifth bridge circuit C5.

[0103] The strain gauges Rq and Rs are connected in series. The strain gauges Rt and Rr are connected in series. Moreover, between the + pole and the - pole of the power supply voltage, the column of the two strain gauges Rq and Rs is connected in parallel with the column of the two strain gauges Rt and Rr. In addition, the fifth voltmeter V5 is connected between the middle point M51 of the two strain gauges Rq and Rs and the middle point M52 of the two strain gauges Rt and Rr.

[0104] The plurality of resistance wires r3 included in the four strain gauges Rq, Rr, Rs, and Rt of the first thrust sensor 81 all extend in the radial direction. Therefore, the change in the resistance value of the strain gauges Rq, Rr, Rs, and Rt caused by the circumferential torque is extremely small. However, when the diaphragm portion 33 of the flexible gear 30 is displaced in the axial direction, the resistance value of the strain gauges Rq, Rr, Rs, and Rt changes.

[0105] Specifically, when the radial inner end of the diaphragm portion 33 is displaced in a direction approaching the internal gear 20, the resistance values ​​of the two outer strain gauges Rq and Rr among the four strain gauges Rq, Rr, Rs, and Rt increase, and the resistance values ​​of the two inner strain gauges Rs and Rt decrease. On the other hand, when the radial inner end of the diaphragm portion 33 is displaced in a direction away from the internal gear 20, the resistance values ​​of the two outer strain gauges Rq and Rr among the four strain gauges Rq, Rr, Rs, and Rt decrease, and the resistance values ​​of the two inner strain gauges Rs and Rt increase. In this way, the two outer strain gauges Rq and Rr and the two inner strain gauges Rs and Rt show resistance value changes that are opposite to each other with respect to the axial displacement of the diaphragm portion 33.

[0106] Furthermore, when the resistance values ​​of the four strain gauges Rq, Rr, Rs, and Rt change, the potential difference between the middle point M51 of the two strain gauges Rq and Rs and the middle point M52 of the two strain gauges Rt and Rr changes, so the measurement value of the fifth voltmeter V5 also changes. The signal processing circuit 52 detects the direction and magnitude of the thrust applied to the flexible gear 30 based on the measurement value of the fifth voltmeter V5.

[0107] Fig.13 8 is a circuit diagram of the sixth bridge circuit C6 including the four strain gauges Ru, Rv, Rw, and Rx of the second thrust sensor 82. Fig.13 As shown, the four strain gauges Ru, Rv, Rw, and Rx are interconnected to form a sixth bridge circuit C6.

[0108] The strain gauge Ru and the strain gauge Rw are connected in series. The strain gauge Rx and the strain gauge Rv are connected in series. Moreover, between the + pole and the - pole of the power supply voltage, the column of the two strain gauges Ru and Rw is connected in parallel with the column of the two strain gauges Rx and Rv. In addition, the sixth voltmeter V6 is connected between the middle point M61 of the two strain gauges Ru and Rw and the middle point M62 of the two strain gauges Rx and Rv.

[0109] The plurality of resistance wires r4 included in the four strain gauges Ru, Rv, Rw, and Rx of the second thrust sensor 82 all extend in the radial direction. Therefore, the change in the resistance value of the strain gauges Ru, Rv, Rw, and Rx caused by the circumferential torque is extremely small. However, when the diaphragm portion 33 of the flexible gear 30 is displaced in the axial direction, the resistance value of the strain gauges Ru, Rv, Rw, and Rx changes.

[0110] Specifically, when the radial inner end of the diaphragm portion 33 is displaced in a direction approaching the internal gear 20, the resistance values ​​of the two outer strain gauges Ru, Rv among the four strain gauges Ru, Rv, Rw, and Rx increase, and the resistance values ​​of the two inner strain gauges Rw and Rx decrease. On the other hand, when the radial inner end of the diaphragm portion 33 is displaced in a direction away from the internal gear 20, the resistance values ​​of the two outer strain gauges Ru, Rv among the four strain gauges Ru, Rv, Rw, and Rx decrease, and the resistance values ​​of the two inner strain gauges Rw and Rx increase. In this way, the two outer strain gauges Ru, Rv and the two inner strain gauges Rw, Rx show resistance value changes that are opposite to each other with respect to the axial displacement of the diaphragm portion 33.

[0111] When the resistance values ​​of the four strain gauges Ru, Rv, Rw, and Rx change, the potential difference between the middle point M61 of the two strain gauges Ru and Rw and the middle point M62 of the two strain gauges Rx and Rv changes, so the measurement value of the sixth voltmeter V6 also changes. The signal processing circuit 52 detects the direction and magnitude of the thrust applied to the flexible gear 30 based on the measurement value of the sixth voltmeter V6.

[0112] In addition, the signal processing circuit 52 corrects the output signals of the first torque sensor 61 and the second torque sensor 62 according to the thrust detected by any one of the two thrust sensors 81 and 82. Specifically, the output signals of the first torque sensor 61 and the second torque sensor 62 are increased or decreased in a direction to eliminate the influence of the axial displacement of the diaphragm portion 33. Thus, the signal processing circuit 52 can output the torque applied to the flexible gear 30 with higher accuracy.

[0113] In addition, the speed reducer 1 of the present embodiment has two thrust sensors 81 and 82. The signal processing circuit 52 uses any one of the output signals of the two thrust sensors 81 and 82 as the output signal of the thrust sensor 80. By having two thrust sensors 81 and 82, even if an abnormality occurs in one of the thrust sensors, the thrust can be detected by the other thrust sensor. In addition, when an abnormality occurs in one of the thrust sensors, the abnormality can be detected.

[0114] <3-5. Temperature sensor>

[0115] The temperature sensor 90 is a sensor for detecting the temperature of the flexible gear 30. That is, the temperature sensor 90 is a sensor whose output signal changes according to the temperature of the flexible gear 30. Figure 6 As shown, the temperature sensor 90 of the present embodiment includes a first temperature sensor 91 and a second temperature sensor 92 .

[0116] The first temperature sensor 91 has a resistance wire r5. The resistance wire r5 is arranged at a position radially inward of the torque sensor 60. The resistance wire r5 is arranged in an arc shape within a range of about 360° centered on the central axis 9. Therefore, even if the diaphragm portion 33 is displaced in the circumferential direction, radial direction or axial direction, the resistance value of the resistance wire r5 hardly changes. Therefore, the resistance value of the resistance wire r5 is subject to changes in temperature. The signal processing circuit 52 measures the resistance value of the resistance wire r5 based on the output signal from the bridge circuit composed of the resistance wire r5 and the fixed resistor. Then, the signal processing circuit 52 detects the temperature of the flexible gear 30 based on the measured resistance value.

[0117] The second temperature sensor 92 has a resistance wire r6. The resistance wire r6 is arranged at a position radially outward from the torque sensor 60. The resistance wire r6 is arranged in an arc shape within a range of about 360° centered on the central axis 9. Therefore, even if the diaphragm portion 33 is displaced in the circumferential direction, radial direction or axial direction, the resistance value of the resistance wire r6 hardly changes. Therefore, the resistance value of the resistance wire r6 is subject to changes in temperature. The signal processing circuit 52 measures the resistance value of the resistance wire r6 based on the output signal from the bridge circuit composed of the resistance wire r6 and the fixed resistor. Then, the signal processing circuit 52 detects the temperature of the flexible gear 30 based on the measured resistance value.

[0118] In addition, the signal processing circuit 52 corrects the output signals of the first torque sensor 61 and the second torque sensor 62 according to the temperature detected by either of the two temperature sensors 91 and 92. Specifically, the output signals of the first torque sensor 61 and the second torque sensor 62 are increased or decreased in a direction to eliminate the influence of the temperature. Thus, the signal processing circuit 52 can output the torque applied to the flexible gear 30 with higher accuracy.

[0119] In addition, the reducer 1 of the present embodiment has two temperature sensors 91 and 92. The signal processing circuit 52 uses any one of the output signals of the two temperature sensors 91 and 92 as the output signal of the temperature sensor 90. By having two temperature sensors 91 and 92, even if an abnormality occurs in one of the temperature sensors, the temperature of the flexible gear 30 can be detected by the other temperature sensor. In addition, when an abnormality occurs in one of the temperature sensors, the abnormality can be detected.

[0120] <4. About the control of the control unit>

[0121] The control unit 2 controls the motor 103 based on the detection value of the sensor 50 . Fig.14 : is a flowchart showing the flow of the control by the control unit 2 .

[0122] The control unit 2 determines whether the difference between the output signals of the two sensors is greater than or equal to a predetermined threshold value (step S1). Specifically, the control unit 2 determines whether the difference between the output signals of the two temperature sensors 91 and 92 is greater than or equal to a first threshold value pre-stored in the storage unit 203. In addition, the control unit 2 determines whether the difference between the output signals of the two torque sensors 61 and 62 is greater than or equal to a second threshold value pre-stored in the storage unit 203. In addition, the control unit 2 determines whether the difference between the output signals of the two thrust sensors 81 and 82 is greater than or equal to a third threshold value pre-stored in the storage unit 203.

[0123] Then, when the difference between the output signals of the two sensors is greater than the above threshold value (step S1: "Yes"), the control unit 2 performs alarm control (step S2). Alarm control is, for example, the output of an alarm. The output of an alarm may be the display of an alarm on a display, the lighting of a warning light, or the sounding of a warning sound. In addition, the alarm control may also be the control unit 2 stopping or limiting the operation of the drive device 100. In addition, the alarm control may also be a situation in which the operation of the drive device 100 can be controlled without issuing information that can be perceived by humans.

[0124] Specifically, when the difference between the output signals of the two temperature sensors 91 and 92 is equal to or greater than the first threshold, the control unit 2 performs alarm control. Also, when the difference between the output signals of the two torque sensors 61 and 62 is equal to or greater than the second threshold, the control unit 2 performs alarm control. Also, when the difference between the output signals of the two thrust sensors 81 and 82 is equal to or greater than the third threshold, the control unit 2 performs alarm control.

[0125] When the difference between the output signals of the two sensors is greater than the threshold value, it is possible that a fault has occurred in one of the two sensors. Therefore, the control unit 2 performs the above-mentioned alarm control. Thus, the user of the drive device 100 can confirm whether there is a fault or deal with a fault. In addition, depending on the situation, the user can also control the operation of the drive device 100 without confirming the abnormality of the drive device 100.

[0126] In step S1, when the difference between the output signals of the two sensors is not equal to or greater than the threshold value (step S1: No), the control unit 2 then determines whether the value of the output signal of the sensor 50 deviates from a predetermined allowable range (step S3). Specifically, the control unit 2 determines whether the value of the output signal of the temperature sensor 90 deviates from the first allowable range pre-stored in the storage unit 203. In addition, the control unit 2 determines whether the value of the output signal of the torque sensor 60 deviates from the second allowable range pre-stored in the storage unit 203. In addition, the control unit 2 determines whether the value of the output signal of the thrust sensor 80 deviates from the third allowable range pre-stored in the storage unit 203.

[0127] Then, when the value of the output signal of the sensor 50 deviates from the above-mentioned permissible range (step S3: "Yes"), the control unit 2 performs alarm control (step S4). The alarm control is, for example, the output of an alarm. The output of an alarm may be the display of an alarm on a display, the lighting of a warning light, or the sounding of a warning sound. In addition, the alarm control may also be the control unit 2 stopping or limiting the operation of the drive device 100. In addition, the alarm control may also be a situation in which the operation of the drive device 100 can be controlled without issuing information that can be perceived by humans.

[0128] Specifically, when the value of the output signal of the temperature sensor 90 deviates from the first allowable range, the control unit 2 performs an alarm control. In addition, when the value of the output signal of the torque sensor 60 deviates from the second allowable range, the control unit 2 performs an alarm control. In addition, when the value of the output signal of the thrust sensor 80 deviates from the third allowable range, the control unit 2 performs an alarm control.

[0129] When the value of the output signal of the temperature sensor 90 deviates from the first allowable range, it indicates that the temperature of the flexible gear 30 is abnormal. When the value of the output signal of the torque sensor 60 deviates from the second allowable range, it indicates that the torque applied to the flexible gear 30 is abnormal. In addition, when the value of the output signal of the thrust sensor 80 deviates from the third allowable range, it indicates that the thrust applied to the flexible gear 30 is abnormal. Therefore, the control unit 2 performs the above-mentioned alarm control. As a result, the user of the drive device 100 can cope with the situation. In addition, depending on the situation, the user can also control the operation of the drive device 100 without confirming the abnormality of the drive device 100.

[0130] In step S3 , when the value of the output signal of the sensor 50 does not deviate from the allowable range (step S3 : No), the control unit 2 controls the motor 103 based on the output signal of the sensor 50 (step S5 ).

[0131] Specifically, the control unit 2 controls the motor 103 based on the detection signal of the temperature sensor 90. The detection signal of the temperature sensor 90 is related to the amount of expansion or contraction of the arm 102 caused by the change in temperature. In particular, the temperature sensor 90 is arranged at a position closer to the arm 102 than the motor 103. Therefore, the detection signal of the temperature sensor 90 becomes a signal that reflects the amount of expansion or contraction of the arm 102 with high accuracy. Therefore, by controlling the motor 103 based on the detection signal of the temperature sensor 90, it is possible to perform control with high accuracy that takes into account the amount of expansion or contraction of the arm 102 caused by the change in temperature.

[0132] In addition, the control unit 2 controls the motor 103 based on the detection signal of the torque sensor 60. The detection signal of the torque sensor 60 reflects the torque applied to the flexible gear 30 due to the swing in the rotation direction of the arm 102. In particular, the torque sensor 60 is arranged at a position closer to the arm 102 than the motor 103. Therefore, the detection signal of the torque sensor 60 becomes a signal that reflects the swing in the rotation direction of the arm 102 with high accuracy. Therefore, by controlling the motor 103 based on the detection signal of the torque sensor 60, it is possible to perform control that takes into account the swing in the rotation direction of the arm 102 with high accuracy.

[0133] In addition, the sensor 50 of this embodiment is attached to the flexible gear 30 of the reducer 1. The sensor 50 can also be used to detect the state of the reducer 1 itself, and can also be used to detect the state of the arm 102 as described above. Therefore, it is not necessary to separately provide a sensor for detecting the state of the reducer 1 itself and a sensor for detecting the state of the arm 102. As a result, the number of sensors mounted on the drive device 100 can be reduced. In addition, the structure in the case where the drive device 100 is equipped with a sensor can be simplified.

[0134] <5. Modifications>

[0135] Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. Various modifications will be described below, centering on the differences from the above embodiment.

[0136] <5-1. First Modification>

[0137] Fig.15 FIG. 1 is a schematic diagram of a driving device 100 according to a first variation. Fig.15 As shown, the drive device 100 may also include a plurality of motors, a plurality of speed reducers for reducing the rotational motions outputted from the plurality of motors, and a plurality of objects for moving by the rotational motions outputted from the plurality of speed reducers. Fig.15 In the example, the drive device 100 has two motors 103A and 103B, two reducers 1A and 1B that reduce the rotational motion output from the two motors 103A and 103B, and two arms 102A and 102B that move by the rotational motion output from the two reducers 1A and 1B.

[0138] The arm 102A is supported so as to be rotatable relative to the base frame 101. The motor 103A and the reducer 1A are assembled at the first joint between the base frame 101 and the arm 102A. When a driving current is supplied to the motor 103A, a rotational motion is output from the motor 103A. The reducer 1A decelerates the rotational motion output from the motor 103A and transmits it to the arm 102A. Thus, the arm 102A rotates at a decelerated speed relative to the base frame 101. That is, the arm 102A is an object that moves by the rotational motion output from the reducer 1A.

[0139] The arm 102B is supported so as to be rotatable relative to the arm 102A. The motor 103B and the reducer 1B are assembled at the second joint between the arm 102A and the arm 102B. When a driving current is supplied to the motor 103B, a rotational motion is output from the motor 103B. The reducer 1B decelerates the rotational motion output from the motor 103B and transmits it to the arm 102B. Thus, the arm 102B rotates at a decelerated speed relative to the arm 102A. That is, the arm 102B is an object that moves by the rotational motion output from the reducer 1B.

[0140] In this case, the control unit 2 may also control the motor 103A of the first joint according to the detection value of the sensor 50 of the reducer 1B mounted on the second joint. In this way, the motor 103A of the first joint can be controlled in consideration of the swing in the rotation direction, the vibration in the axial direction, the expansion amount or the contraction amount of the arm 102B as the object located at the position closest to the front end. Thus, the position of the front end of the arm 102B can be controlled with higher accuracy.

[0141] Furthermore, the control unit 2 may control the motor 103A of the first joint portion based on the detection values ​​of both the sensor 50 of the speed reducer 1A mounted on the first joint portion and the sensor 50 of the speed reducer 1B mounted on the second joint portion.

[0142] In this way, the control unit 2 may control at least one of the plurality of motors 103 based on the detection value of the sensor 50 mounted on at least one of the plurality of speed reducers 1 .

[0143] <5-2. Other Modifications>

[0144] In the above-mentioned embodiment, one driving device 100 has one control unit 2. However, the control unit 2 may be a system that collectively controls a plurality of driving devices 100.

[0145] In the above embodiment, the sensor 50 includes the torque sensor 60, the angle sensor 70, the thrust sensor 80, and the temperature sensor 90. However, the sensor 50 may include only some of the torque sensor 60, the angle sensor 70, the thrust sensor 80, and the temperature sensor 90.

[0146] In the above embodiment, the torque sensor 60 includes the first torque sensor 61 and the second torque sensor 62. However, the torque sensor 60 may be only one of the first torque sensor 61 and the second torque sensor 62.

[0147] In the above-described embodiment, the thrust sensor 80 includes the first thrust sensor 81 and the second thrust sensor 82. However, the thrust sensor 80 may be only one of the first thrust sensor 81 and the second thrust sensor 82.

[0148] In the above-described embodiment, the temperature sensor 90 includes the first temperature sensor 91 and the second temperature sensor 92. However, the temperature sensor 90 may be only one of the first temperature sensor 91 and the second temperature sensor 92.

[0149] In the above embodiment, the sensor 50 is mounted on the flexible gear 30 . However, the sensor 50 may be mounted on the internal gear 20 instead of the flexible gear 30 .

[0150] In the reducer 1 of the above embodiment, the flexible gear 30 is fixed to the base frame 101 and the internal gear 20 rotates at the reduced second speed. However, the internal gear 20 may be fixed to the base frame 101 and the flexible gear 30 may rotate at the reduced second speed.

[0151] The flexible gear 30 of the above embodiment is a so-called "hat-shaped" gear in which the diaphragm portion 33 extends radially outward from the body portion 31. However, the flexible gear 30 may be a so-called "cup-shaped" gear in which the diaphragm portion 33 extends radially inward from the body portion 31.

[0152] In the above embodiment, the driving device 100 is an industrial robot having an arm, but the driving device 100 may be another device such as an assist suit or an unmanned transport vehicle.

[0153] In addition, the detailed structures of the motor, reducer, drive device and control unit may be appropriately changed without departing from the gist of the present invention. In addition, the elements in the above-mentioned embodiments and modified examples may be appropriately combined without causing contradictions.

[0154] <6. Conclusion>

[0155] The present technology can adopt the following structures.

[0156] (1) A control unit is a control unit of a drive device, the drive device comprising: a motor; a reducer that reduces the speed of rotational motion output from the motor; and an object that moves according to the rotational motion output from the reducer, wherein the control unit controls the motor based on a detection value of a sensor mounted on the reducer.

[0157] (2) A control unit is a control unit of a driving device, the driving device comprising: a plurality of motors; a plurality of reducers, the plurality of reducers reduce the speed of rotational motion outputted from the plurality of motors; and a plurality of objects, the plurality of objects are moved by the rotational motion outputted from the plurality of reducers, wherein the control unit controls at least one of the plurality of motors according to a detection value of a sensor mounted on at least one of the plurality of reducers.

[0158] (3) The control unit according to (1) or (2), wherein the sensor includes a strain gauge mounted on a gear of the speed reducer.

[0159] (4) The control unit according to any one of (1) to (3), wherein the sensor is a temperature sensor whose output signal changes according to a temperature of the gear.

[0160] (5) The control unit according to (4), wherein the speed reducer has two temperature sensors, and the control unit performs alarm control when a difference between output signals of the two temperature sensors is equal to or larger than a predetermined threshold value.

[0161] (6) The control unit according to (4) or (5), wherein the control unit performs alarm control when the value of the output signal of the temperature sensor deviates from a predetermined allowable range.

[0162] (7) The control unit according to any one of (1) to (3), wherein the sensor is a torque sensor whose output signal changes according to a torque applied to the gear.

[0163] (8) The control unit according to (7), wherein the speed reducer has two torque sensors, and the control unit performs alarm control when a difference between output signals of the two torque sensors is equal to or greater than a predetermined threshold value.

[0164] (9) The control unit according to (7) or (8), wherein the control unit performs alarm control when the value of the output signal of the torque sensor deviates from a predetermined allowable range.

[0165] (10) The control unit according to any one of (1) to (3), wherein:

[0166] The sensor is a thrust sensor whose output signal varies according to thrust applied to the gear.

[0167] (11) The control unit according to (10), wherein the speed reducer has two thrust sensors, and the control unit performs alarm control when a difference between output signals of the two thrust sensors is equal to or greater than a predetermined threshold value.

[0168] (12) The control unit according to (10) or (11), wherein:

[0169] The control unit performs an alarm control when the value of the output signal of the thrust sensor deviates from a predetermined allowable range.

[0170] (13) A driving device comprising the control unit described in any one of (1) to (12), the motor, the speed reducer, and the object.

[0171] (14) A control method is a control method for a drive device, the drive device comprising: a motor; a reducer that reduces the speed of rotational motion output from the motor; and an object that moves according to the rotational motion output from the reducer, wherein the motor is controlled based on a detection value of a sensor mounted on the reducer.

[0172] (15) A control method is a control method for a drive device, the drive device comprising: a plurality of motors; a plurality of reducers, the plurality of reducers reducing the speed of rotational motion respectively output from the plurality of motors; and a plurality of objects, the plurality of objects being moved by the rotational motion respectively output from the plurality of reducers, wherein at least one of the plurality of motors is controlled based on a detection value of a sensor mounted on at least one of the plurality of reducers.

[0173] The present invention can be utilized in, for example, a control unit, a drive device, and a control method.

Claims

1. A control unit is a control unit of a drive device, the drive device having: motor; a speed reducer that reduces the speed of the rotational motion output from the motor; and an object that moves by the rotational motion output from the speed reducer, It is characterized in that The control unit controls the motor according to a detection value of a sensor mounted on the speed reducer.

2. A control unit is a control unit of a drive device, the drive device having: Multiple motors; a plurality of speed reducers for reducing the speed of rotational motions respectively output from the plurality of motors; as well as a plurality of objects that are moved by the rotational motions outputted from the plurality of speed reducers, respectively; It is characterized in that The control unit controls at least one of the plurality of motors based on a detection value of a sensor mounted on at least one of the plurality of speed reducers.

3. The control unit according to claim 1 or 2, characterized in that: The sensor includes a strain gauge mounted on a gear of the speed reducer.

4. The control unit according to claim 3, characterized in that: The sensor is a temperature sensor whose output signal varies according to the temperature of the gear.

5. The control unit according to claim 4, characterized in that: The reducer has two temperature sensors. The control unit performs alarm control when the difference between the output signals of the two temperature sensors is equal to or larger than a predetermined threshold value.

6. The control unit according to claim 4, characterized in that The control unit performs an alarm control when the value of the output signal of the temperature sensor deviates from a predetermined allowable range.

7. The control unit according to claim 3, characterized in that: The sensor is a torque sensor whose output signal varies according to torque applied to the gear.

8. The control unit according to claim 7, characterized in that The reducer has two torque sensors. The control unit performs alarm control when the difference between the output signals of the two torque sensors is equal to or larger than a predetermined threshold value.

9. The control unit according to claim 7, characterized in that: The control unit performs an alarm control when the value of the output signal of the torque sensor deviates from a predetermined allowable range.

10. The control unit according to claim 3, characterized in that: The sensor is a thrust sensor whose output signal varies according to thrust applied to the gear.

11. The control unit according to claim 10, characterized in that The reducer has two thrust sensors. The control unit performs alarm control when the difference between the output signals of the two thrust sensors is equal to or larger than a predetermined threshold value.

12. The control unit according to claim 10, characterized in that The control unit performs an alarm control when the value of the output signal of the thrust sensor deviates from a predetermined allowable range.

13. A driving device, characterized in that: The drive device includes the control unit according to claim 1 or 2, the motor, the speed reducer, and the object.

14. A control method is a control method for a driving device, wherein the driving device comprises: motor; a speed reducer that reduces the speed of the rotational motion output from the motor; and an object that moves by the rotational motion output from the speed reducer, It is characterized in that The motor is controlled based on a detection value of a sensor mounted on the speed reducer.

15. A control method is a control method for a driving device, wherein the driving device comprises: Multiple motors; a plurality of speed reducers for reducing the speed of rotational motions respectively output from the plurality of motors; as well as a plurality of objects that are moved by the rotational motions outputted from the plurality of speed reducers, respectively; It is characterized in that At least one of the plurality of motors is controlled based on a detection value of a sensor mounted on at least one of the plurality of speed reducers.

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