Movable device and robot

Abstract

To provide a regenerative movable device and a robot.SOLUTION: A movable device has: a first member; a second member which is rotated with respect to the first member; a first motor which rotates the second member with respect to the first member; and a second motor which is driven by the rotation of the second member and generates regenerative power. The first motor does not generate the regenerative power, and the second motor does not rotate the second member. The first motor is a servo motor, and the second motor is a stepping motor.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a mobile device and a robot. [Background technology]

[0002] The robot described in Patent Document 1 has a robot mechanism with multiple joints and a drive unit disposed at each joint to rotate the joint. The drive unit rotates the joints through cooperation between a first motor and a second motor. This allows the joints to be rotated with a larger torque. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-195879 Summary of the Invention [Problem to be solved by the invention]

[0004] However, Patent Document 1 does not give any consideration to regeneration of the first motor and the second motor. [Means for solving the problem]

[0005] The movable device of the present invention comprises: a first member; a second member that rotates relative to the first member; a first motor that rotates the second member relative to the first member; and a second motor that is driven by the rotation of the second member and generates regenerative power.

[0006] The robot of the present invention includes a first member and a second member that rotates relative to the first member; a first motor and a second motor that rotate the second member relative to the first member and are driven by the rotation of the second member to generate regenerative power; The regenerative power generated in the first motor is smaller than the regenerative power generated in the second motor, The driving force of the second motor is smaller than the driving force of the first motor. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a side view showing a robot according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing the configuration of a joint. [Figure 3] FIG. 2 is a block diagram showing a circuit configuration of a control device. [Figure 4] FIG. 10 is a diagram illustrating an example of driving the first arm. [Figure 5] FIG. 10 is a cross-sectional view showing a joint provided in a robot according to a second embodiment. [Figure 6] FIG. 10 is a diagram illustrating an example of driving the first arm. [Figure 7] FIG. 11 is a cross-sectional view showing a joint provided in a robot according to a third embodiment. [Figure 8] FIG. 10 is a diagram illustrating an example of driving the first arm. [Figure 9] FIG. 10 is a cross-sectional view showing a joint provided in a robot according to a fourth embodiment. [Figure 10] FIG. 10 is a diagram illustrating an example of driving the first arm. [Figure 11] FIG. 4 is a block diagram showing how regenerative electric power generated by the first motor is supplied to an external device. DETAILED DESCRIPTION OF THE INVENTION

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A movable device and a robot according to the present invention will be described in detail below based on embodiments shown in the accompanying drawings.

[0009] First Embodiment FIG. 1 is a side view showing a robot according to a first embodiment. FIG. 2 is a cross-sectional view showing the configuration of a joint. FIG. 3 is a block diagram showing the circuit configuration of a control device. FIG. 4 is a diagram showing an example of driving a first arm. The up-down direction in FIG. 1 corresponds to the vertical direction, and the upper side in FIG. 1 is also referred to as "up" and the lower side as "down." In addition, in this specification, "vertical" refers not only to the case where the two objects are aligned vertically, but also to the case where the two objects are inclined from the vertical within a range where the effects of the present invention can be achieved. In this specification, "parallel" refers not only to the case where two objects are aligned parallel to each other, but also to the case where the two objects are inclined from the parallel to each other within a range where the effects of the present invention can be achieved.

[0010] The movable device 1 shown in Fig. 1 is a robot 10. The robot 10 is a horizontal articulated robot, i.e., a SCARA robot, and is used for tasks such as holding, transporting, assembling, and inspecting workpieces such as electronic components. However, the uses of the robot 10 are not particularly limited.

[0011] The robot 10 has a base 20 which is a first member fixed to the floor, a robot arm 21 which is rotatably connected to the base 20, and a control device 6 which controls the driving of each part of the robot 10. The robot arm 21 also has a first arm 211 which is a second member connected to the base 20 via a joint S1 which has a rotation axis J1 and which rotates around the rotation axis J1 relative to the base 20, and a second arm 212 which is connected to the first arm 211 via a joint S2 which has a rotation axis J2 and which rotates around the rotation axis J2 relative to the first arm 211.

[0012] A working head 22 is provided at the tip of the second arm 212. The working head 22 has a spline nut 221 and a ball screw nut 222 that are coaxially arranged at the tip of the second arm 212, and a spline shaft 223 that is inserted through the spline nut 221 and the ball screw nut 222. The spline shaft 223 is rotatable about a rotation axis J3 with respect to the second arm 212 and is also capable of moving up and down along the rotation axis J3. A mounting portion 223a to which an end effector (not shown) is attached is provided at the lower end of the spline shaft 223. The end effector is detachable from the mounting portion 223a, and an end effector suitable for the intended work is selected as appropriate.

[0013] In the robot 10 of this embodiment, the rotation axes J1, J2, and J3 are aligned along the vertical direction and parallel to one another, but the orientations of the rotation axes J1, J2, and J3 are not particularly limited.

[0014] Also, although not shown, a motor (not shown) that rotates the spline nut 221 to rotate the spline shaft 223 around the rotation axis J3, and a motor (not shown) that rotates the ball screw nut 222 to move the spline shaft 223 in a direction along the rotation axis J3 are arranged within the second arm 212.

[0015] As shown in FIG. 2, a first reducer 40, a first motor 41, a second motor 42, a first clutch 43, and a second clutch 44 are arranged at the joint S1.

[0016] The first reducer 40 is, for example, a wave gear device, in which a circular spline (hereinafter also referred to as the "output shaft") is fixed to the base 20, a flexspline is fixed to the first arm 211, and a wave generator (hereinafter also referred to as the "input shaft") is rotatably supported relative to the base 20. As a result, the base 20 and the first arm 211 are rotatably connected via the first reducer 40. A first motor 41 is connected to the input shaft of the first reducer 40. In this configuration, the wave generator is rotated by driving the first motor 41, and the flexspline further rotates at a predetermined reduction ratio relative to the rotation of the wave generator, resulting in the first arm 211 rotating about the rotation axis J1 relative to the base 20. By using a wave gear device as the first reducer 40, backlash does not occur and the drive of the first arm 211 can be controlled with high precision. However, the configuration of the first reducer 40 is not particularly limited.

[0017] The first and second motors 41, 42 and the first and second clutches 43, 44 are each disposed within the base 20 and supported by the base 20. The first motor 41 is disposed below the first reduction gear 40, and an output shaft 411 of the first motor 41 is connected to an input shaft of the first reduction gear 40. The first clutch 43 is interposed between the first motor 41 and the first reduction gear 40, and switches between a connected state in which the output shaft 411 of the first motor 41 is connected to the input shaft of the first reduction gear 40, and a disconnected state in which the output shaft 411 of the first motor 41 is disconnected from the input shaft of the first reduction gear 40.

[0018] In contrast, the second motor 42 is disposed above the first reduction gear 40, and an output shaft 421 of the second motor 42 is connected to the input shaft of the first reduction gear 40. The second clutch 44 is interposed between the second motor 42 and the first reduction gear 40 and switches between a connected state in which the output shaft 421 of the second motor 42 is connected to the input shaft of the first reduction gear 40 and a disconnected state in which the output shaft 421 of the second motor 42 is disconnected from the input shaft of the first reduction gear 40. The first and second clutches 43 and 44 are not particularly limited, and may be, for example, magnetic clutches. The magnetic clutch is not particularly limited, and may be a type that is connected when energized or a type that is turned off when energized. The second motor 42 may be connected to the first arm 211 instead of the input shaft of the first reduction gear 40.

[0019] Furthermore, of the first and second motors 41, 42, the first motor 41 is used to drive the first arm 211, and the second motor 42 is used for regeneration. By arranging the first motor 41 for drive and the second motor 42 for regeneration at one joint S1 in this way, the first motor 41 can drive the first arm 211, and the second motor 42 can generate regenerative power using the movement of the first arm 211. This allows for efficient regeneration. Furthermore, by reusing the regenerative power generated by the second motor 42 to drive the control device 6, the robot 10 can achieve power savings.

[0020] In particular, in this embodiment, the first motor 41 is dedicated to driving the first arm 211 and is not used for regeneration. The second motor 42 is dedicated to regeneration and is not used to drive the first arm 211, i.e., to rotate the joint S1. In this way, by clearly dividing the roles of the first and second motors 41, 42 into driving and regeneration, the device configuration of the robot 10 is simplified.

[0021] Furthermore, the first motor 41 is a servo motor, in particular a three-phase motor driven by three-phase AC. By using a servo motor as the first motor 41, the drive of the first arm 211 can be controlled with high precision and ease. On the other hand, the second motor 42 is a stepping motor. By using a stepping motor as the second motor 42, the regeneration efficiency, that is, the power generation efficiency, can be improved. Furthermore, since DC (direct current) regenerative power can be generated, the regenerative power can be stored directly in the regenerative capacitor 64 without using a converter, as will be described later. However, the types of the first and second motors 41, 42 are not particularly limited.

[0022] As shown in FIG. 1 , a reducer 50 and a motor 51 are disposed at the joint S2. The reducer 50 is, for example, a wave gear device similar to the first reducer 40, with the circular spline fixed to the second arm 212 and the flexspline fixed to the first arm 211. This allows the first arm 211 and the second arm 212 to be rotatably connected via the reducer 50. A wave generator is also connected to the motor 51. In this configuration, the wave generator is rotated by the drive of the motor 51, and the flexspline rotates at a predetermined reduction ratio relative to the rotation of the wave generator. As a result, the second arm 212 rotates around the rotation axis J2 relative to the first arm 211. Using a wave gear device as the reducer 50 prevents backlash and enables highly accurate control of the drive of the second arm 212. However, the configuration of the reducer 50 is not particularly limited.

[0023] The control device 6 controls the driving of each part of the robot 10. Such a control device 6 is composed of, for example, a computer, and has a processor (CPU) that processes information, a memory communicatively connected to the processor, and an external interface that connects to external devices. Various programs that can be executed by the processor are stored in the memory, and the processor can read and execute the programs stored in the memory.

[0024] As shown in FIG. 3 , the control device 6 includes, as a motor control circuit, a power supply input unit 61 to which an AC power source is input, a converter circuit 62 that converts the AC current output from the power supply input unit 61 into DC current, a drive circuit 63 connected to the output side of the converter circuit 62 and controlling the drive of the first motor 41, and a regenerative capacitor 64 and a discharge resistor 65 arranged in parallel between the converter circuit 62 and the drive circuit 63. A switch (not shown) is provided in the discharge resistor 65, and power is supplied to the discharge resistor 65 when the switch is turned ON. The drive circuit 63 performs PWM control, converting the DC current output from the converter circuit 62 into three-phase AC current and selectively supplying it to the first motor 41. For ease of explanation, FIG. 3 shows only the drive circuit 63 for the first motor 41, but multiple drive circuits 63 are provided for each motor.

[0025] The above has described the configuration of the robot 10. Next, a regenerative method for the robot 10 will be described using an example in which the first arm 211 is moved from a start point P1 to an end point P2 as shown in Fig. 4. Note that Fig. 4 is just an example, and the movement of the first arm 211 and the method for controlling the first arm 211 are not particularly limited.

[0026] First, at first timing T1, the control device 6 brings the first clutch 43 into an engaged state and the second clutch 44 into a disengaged state. Note that the first timing T1 refers to the timing before the first arm 211 starts to move from the start point P1 toward the end point P2, or the timing at which the first arm 211 starts to move from the start point P1 toward the end point P2. As a result, the first motor 41, which is dedicated to driving, is connected to the first arm 211, and the second motor 42, which is dedicated to regeneration, is disconnected from the first arm 211. By disconnecting the second motor 42 from the first arm 211 in this way, the load applied to the first motor 41 when moving the first arm 211 is reduced. This reduces the power consumption of the first motor 41.

[0027] Next, the control device 6 controls the driving of the first motor 41 to accelerate the movement of the first arm 211 until the speed of the first arm 211 reaches a predetermined speed V1, and then moves the first arm 211 at a constant speed at the predetermined speed V1. Next, at a second timing T2, the control device 6 disengages the first clutch 43 and cuts off the driving force of the first motor 41, thereby decelerating the movement of the first arm 211 and stopping it at the end point P2. By decelerating the movement of the first arm 211 with the first clutch 43 in the disengaged state in this manner, it is possible to suppress the generation of regenerative power (back electromotive force) from the first motor 41 during the deceleration movement of the first arm 211. Note that it is preferable to stop the supply of electricity to the first motor 41 immediately when or after the first clutch 43 is disengaged. This prevents unnecessary current from being supplied to the first motor 41, thereby reducing unnecessary power consumption.

[0028] Furthermore, the control device 6 connects the second clutch 44 at a third timing T3. The third timing T3 is a timing during which the first arm 211 is decelerating. This connects the first arm 211 and the second motor 42, and the decelerating movement of the first arm 211 generates regenerative power (back electromotive force) from the second motor 42. The regenerative power generated by the second motor 42 is stored in the regenerative capacitor 64 and reused as power for the control device 6. This reduces the power consumption of the robot 10, thereby achieving power savings. In particular, in the robot 10, the drive direction of the first arm 211 is frequently switched, and the first arm 211 frequently accelerates and decelerates. This makes it easier for the second motor 42 to generate regenerative power, allowing more regenerative power to be generated and reused.

[0029] In this way, by engaging the second clutch 44 only when the first arm 211 is decelerating, the second motor 42 does not become a load when the first arm 211 is accelerating or moving at a constant speed, allowing the first arm 211 to move smoothly. On the other hand, when the first arm 211 is decelerating, the second motor 42 becomes a load, that is, acts as a brake, allowing the first arm 211 to decelerate and stop more quickly. Therefore, the first arm 211 can move smoothly from the start point P1 to the end point P2 in a short time. Furthermore, even when regeneration is performed only during deceleration, a sufficient amount of regenerative power can be generated from the second motor 42.

[0030] Here, the second motor 42 is a stepping motor, and therefore generates regenerative DC power. Therefore, the regenerative power can be stored directly in the regenerative capacitor 64. This means that a converter for converting between AC and DC is not required, simplifying the circuit configuration of the control device 6. When the capacity of the regenerative capacitor 64 is exceeded, a switch disposed in the discharge resistor 65 turns ON, and the remaining power is converted into heat by the discharge resistor 65 and discharged.

[0031] The timing at which the second clutch 44 is brought into the engaged state when the first arm 211 is decelerating is not particularly limited. In this embodiment, the second clutch 44 is brought into the engaged state when the movement speed of the first arm 211 becomes equal to or less than a preset threshold value SH. This simplifies the control of the second clutch 44. The movement speed of the first arm 211 can be calculated, for example, by disposing an inertial sensor in the first arm 211 and based on the acceleration or angular velocity of the first arm 211 detected by the inertial sensor. Alternatively, for example, the movement speed can be calculated based on the output of an encoder disposed in the first arm 211.

[0032] The movable device 1 has been described above. As mentioned above, such a movable device 1 is the robot 10. In this way, by applying the movable device 1 to the robot 10, it becomes possible to drive the robot 10 in a power-saving manner. In particular, in the robot 10, the drive direction of the first arm 211 is often switched, and the first arm 211 undergoes frequent acceleration and deceleration movements. Therefore, regenerative power is easily generated from the second motor 42, and more regenerative power can be reused.

[0033] The robot 10 also has a base 20 as a first member, a first arm 211 as a second member that rotates relative to the base 20, a first motor 41 that rotates the first arm 211 relative to the base 20, and a second motor 42 that is driven by the rotation of the first arm 211 and generates regenerative power. By providing the first motor 41 for driving and the second motor 42 for regeneration in this manner, the first motor 41 can drive the first arm 211, and the second motor 42 can generate regenerative power using the movement of the first arm 211. Therefore, more efficient regeneration can be achieved than, for example, when one motor is used for both driving and regeneration.

[0034] As described above, the robot 10 also has a control device 6 that controls the driving of the first motor 41. The first motor 41 does not generate regenerative power, and the second motor 42 does not rotate the joint S1 around the rotation axis J1. The regenerative power generated by the second motor 42 is stored in a regenerative capacitor 64 provided in the control device 6. In this way, the first motor 41 is dedicated to driving the first arm 211, and the second motor 42 is dedicated to regenerative power, and by clearly separating the roles of the first and second motors 41, 42, the device configuration of the robot 10 is simplified. Furthermore, by storing the regenerative power generated by the second motor 42 in the regenerative capacitor 64, the regenerative power can be reused as power for the control device 6, thereby reducing the power consumption of the robot 10.

[0035] As described above, the first motor 41 is a servo motor, and the second motor 42 is a stepping motor. By using a servo motor as the first motor 41, the drive of the first arm 211 can be controlled with high precision and ease. Furthermore, by using a stepping motor as the second motor 42, the regeneration efficiency, that is, the power generation efficiency, can be improved. Furthermore, DC (direct current) regenerative power can be generated.

[0036] As described above, the robot 10 has the first clutch 43 that switches between a connected state in which the first motor 41 and the first arm 211 are connected and a disconnected state in which the first motor 41 and the first arm 211 are disconnected. Therefore, by switching the first clutch 43 to the disconnected state when the first arm 211 is decelerating, it is possible to suppress the generation of regenerative power in the first motor 41. This prevents unnecessary current from flowing to the first motor 41, thereby reducing unnecessary power consumption.

[0037] As described above, the robot 10 has the second clutch 44 that switches between a connected state in which the second motor 42 and the first arm 211 are connected and a disconnected state in which the second motor 42 and the first arm 211 are disconnected. With this configuration, by switching the second clutch 44 to the disconnected state when the first arm 211 is moving at an accelerated speed or at a constant speed, the load applied to the first motor 41 can be reduced, and the power consumption of the first motor 41 can be reduced.

[0038] Furthermore, as described above, in the robot 10, the second clutch 44 switches from a disengaged state to a connected state when the first arm 211 decelerates. As a result, the second motor 42 is driven by the decelerated movement of the first arm 211, and regenerative power is generated from the second motor 42.

[0039] Second Embodiment Fig. 5 is a cross-sectional view showing a joint included in the robot according to the second embodiment Fig. 6 is a diagram showing an example of driving the first arm.

[0040] The robot 10 according to this embodiment is similar to the robot 10 according to the first embodiment, except for the configuration of the joint S1. In the following description, differences between the robot 10 according to this embodiment and the first embodiment will be mainly described, and descriptions of similar points will be omitted. In addition, in each drawing of this embodiment, the same reference numerals are used to designate the same components as those in the above-described embodiment.

[0041] As shown in FIG. 5, first and second reducers 40, 45, first and second motors 41, 42, and first and second clutches 43, 44 are arranged at a joint S1 of the robot 10 of this embodiment.

[0042] The first reducer 40 rotatably connects the first arm 211 to the base 20 below the base end of the first arm 211. The first motor 41 is located below the first reducer 40, and the first clutch 43 is disposed between the first motor 41 and the first reducer 40. The above configuration is the same as that of the first embodiment described above. At the joint S1, the first reducer 40, the first motor 41, and the first clutch 43 configure a drive mechanism 4A for driving the first arm 211.

[0043] Meanwhile, the second reducer 45 rotatably connects the first arm 211 to the base 20 above the base end of the first arm 211. That is, the input shaft of the second reducer 45 is rotatably supported by the base 20, and the output shaft is fixed to the first arm 211. The second motor 42 is located above the second reducer 45, and the output shaft 421 of the second motor 42 is connected to the input shaft of the second reducer 45. The second clutch 44 is interposed between the second motor 42 and the second reducer 45, and switches between a connected state in which the output shaft 421 of the second motor 42 is connected to the input shaft of the second reducer 45, and a disconnected state in which the output shaft 421 of the second motor 42 is disconnected from the input shaft of the second reducer 45. At the joint S2, the second reducer 45, the second motor 42, and the second clutch 44 configure a regenerative mechanism 4B that performs regeneration using the movement of the first arm 211. The second reducer 45 is a planetary gear device, which allows for more efficient power transmission and more efficient regeneration than, for example, a strain wave gear device used as the first reducer 40.

[0044] In this way, by providing the first reducer 40 in the drive mechanism 4A and the second reducer 45 in the regeneration mechanism 4B, that is, by providing dedicated reducers for each of the drive mechanism 4A and the regeneration mechanism 4B, it is possible to select a preferred reducer configuration and reduction ratio for each of the drive mechanism 4A and the regeneration mechanism 4B. As a result, a drive mechanism 4A suitable for driving and a regeneration mechanism 4B suitable for regeneration are obtained.

[0045] The above has described the configuration of the robot 10. Next, a regenerative method for the robot 10 will be described using an example in which the first arm 211 is moved from the start point P1 to the end point P2 as shown in Fig. 6, similar to the first embodiment described above. Note that Fig. 6 is just an example, and the movement of the first arm 211 and the method for controlling the first arm 211 are not particularly limited.

[0046] First, at a first timing T1, the control device 6 connects the first clutch 43 and disconnects the second clutch 44. Note that the first timing T1 refers to the timing before the first arm 211 starts to move from the start point P1 toward the end point P2, or the timing at which the first arm 211 starts to move from the start point P1 toward the end point P2.

[0047] Next, the control device 6 controls the driving of the first motor 41 to accelerate the movement of the first arm 211 until the speed of the first arm 211 reaches a predetermined speed V1, and then causes the first arm 211 to move at a constant speed at the predetermined speed V1. Next, at a second timing T2, the control device 6 disengages the first clutch 43 and cuts off the driving force of the first motor 41, thereby decelerating the movement of the first arm 211 and stopping it at the end point P2. Furthermore, at a third timing T3, the control device 6 engages the second clutch 44. Note that the third timing T3 is a timing during which the first arm 211 is decelerating. As a result, the first arm 211 and the second motor 42 are coupled, and regenerative power is generated from the second motor 42 due to the decelerating movement of the first arm 211. The regenerative power generated by the second motor 42 is stored in the regenerative capacitor 64 and reused as power for the control device 6.

[0048] The second embodiment can also achieve the same effects as the first embodiment described above.

[0049] <Third embodiment> Fig. 7 is a cross-sectional view showing a joint included in the robot according to the third embodiment Fig. 8 is a diagram showing an example of driving the first arm.

[0050] The robot 10 according to this embodiment is similar to the robot 10 according to the first embodiment, except for the configuration of the joint S1. In the following description, differences between the robot 10 according to this embodiment and the first embodiment will be mainly described, and descriptions of similar points will be omitted. In addition, in each drawing of this embodiment, the same reference numerals are used to designate the same components as those in the above-described embodiment.

[0051] 7, a first reducer 40, first and second motors 41 and 42, and a second clutch 44 are disposed at a joint S1 of the robot 10 of this embodiment. The first motor 41 is located below the first reducer 40, and its output shaft 411 is connected to the input shaft of the first reducer 40. The second motor 42 is located below the first motor 41, and its output shaft 421 is connected to the output shaft 411 of the first motor 41. The second clutch 44 is interposed between the first motor 41 and the second motor 42, and switches between a connected state in which the output shafts 411 and 421 are connected, and a disconnected state in which the output shafts 411 and 421 are disconnected.

[0052] The configuration of the robot 10 has been described above. Next, a regenerative method for the robot 10 will be described using an example in which the first arm 211 is moved from the start point P1 to the end point P2 as shown in Fig. 8, similar to the first embodiment described above. Note that Fig. 8 is just an example, and the movement of the first arm 211 and the method for controlling the first arm 211 are not particularly limited.

[0053] First, the control device 6 disengages the second clutch 44 at a first timing T1. Note that the first timing T1 refers to the timing before the first arm 211 starts to move from the start point P1 toward the end point P2, or the timing at the same time as the first arm 211 starts to move from the start point P1 toward the end point P2. This disconnects the second motor 42 from the first arm 211, reducing the load applied to the first motor 41 when the first arm 211 moves. This allows the first motor 41 to be driven with less power.

[0054] Next, the control device 6 controls the driving of the first motor 41 to accelerate the movement of the first arm 211 until the speed of the first arm 211 reaches a predetermined speed V1, and then causes the first arm 211 to move at a constant speed at the predetermined speed V1. Next, the control device 6 controls the driving of the first motor 41 to decelerate the movement of the first arm 211 and stop it at the end point P2. The control device 6 also connects the second clutch 44 at a third timing T3. Note that the third timing T3 is the timing during which the first arm 211 is decelerating. As a result, the first arm 211 and the second motor 42 are connected, and regenerative power is generated from the second motor 42 due to the decelerating movement of the first arm 211. The regenerative power generated by the second motor 42 is stored in the regenerative capacitor 64 and reused as power for the control device 6. This enables the robot 10 to be driven in a power-saving manner.

[0055] In this embodiment, regenerative power is also generated from the first motor 41 when the first arm 211 decelerates, and the generated line power is also stored in the regenerative capacitor 64. In other words, in this embodiment, the first motor 41 is not used exclusively for driving the first arm 211, but is used for both driving the first arm 211 and for regeneration. Therefore, more power can be regenerated.

[0056] <Fourth embodiment> Fig. 9 is a cross-sectional view showing a joint included in a robot according to a fourth embodiment. Fig. 10 is a diagram showing an example of driving a first arm. Fig. 11 is a block diagram showing a state in which regenerative power generated by a first motor is supplied to an external device.

[0057] The robot 10 according to this embodiment is similar to the robot 10 according to the first embodiment, except for the configuration of the joint S1. In the following description, differences between the robot 10 according to this embodiment and the first embodiment will be mainly described, and descriptions of similar points will be omitted. In addition, in each drawing of this embodiment, the same reference numerals are used to designate the same components as those in the above-described embodiment.

[0058] As shown in FIG. 9, a first reducer 40 and first and second motors 41 and 42 are disposed at a joint S1 of the robot 10 of this embodiment.

[0059] The first reducer 40 is a roller cam reduction gear device, in which a roller follower 401 on the input side meshes with a roller gear cam 402 on the output side. Although not shown, the roller follower 401 is rotatably supported on the base 20, and the roller gear cam 402 is fixed to the first arm 211. An output shaft 411 of the first motor 41 is connected to a base end of the roller follower 401. Meanwhile, the second motor 42 meshes with a tip end of the roller follower 401 via a power transmission unit 46. The power transmission unit 46 has a first gear 461 meshing with the roller follower 401 and a second gear 462 meshing with the first gear 461, and an output shaft 421 of the second motor 42 is connected to the second gear 462. In this power transmission unit 46, a predetermined reduction ratio can be obtained by selecting the gear ratio of the first and second gears 461 and 462.

[0060] In this way, by using a roller cam reduction gear as the first reducer 40, a sufficient distance can be secured between the first motor 41 and the second motor 42, improving the ease of maintenance of the joint S1. In addition, the heat dissipation of the first and second motors 41, 42 can also be improved.

[0061] The joint S1 configured as described above does not have a clutch as in the first embodiment, and therefore the first and second motors 41, 42 are each used for both driving the first arm 211 and for regeneration. In other words, the first arm 211 is driven by both the first and second motors 41, 42, and regeneration is performed by both the first and second motors 41, 42 using the movement of the first arm 211. In this way, in this embodiment, the first and second motors 41, 42 both have the same role, and therefore both the first and second motors 41, 42 are servo motors.

[0062] The above has described the configuration of the robot 10. Next, a regenerative method for the robot 10 will be described using an example in which the first arm 211 is moved from a start point P1 to an end point P2 as shown in Fig. 10, similar to the first embodiment described above. Note that Fig. 10 is just an example, and the movement of the first arm 211 and the method for controlling the first arm 211 are not particularly limited.

[0063] First, the control device 6 controls the driving of the first and second motors 41 and 42, respectively, to accelerate the movement of the first arm 211 until the speed reaches a predetermined speed V1. Thereafter, the control device 6 moves the first arm 211 at a constant speed V1. At this time, the control device 6 preferably sets the driving force of the second motor 42 smaller than the driving force of the first motor 41, causing the first motor 41 to function as a master motor that drives the movement of the first arm 211, and the second motor 42 to function as a slave motor that assists the movement of the first arm 211. In this case, for example, the second motor 42 may be limited to being driven only when a large load is applied, such as at the start of movement. In this way, by using the first motor 41 as the master motor and the second motor 42 as the slave motor, the first arm 211 can be moved smoothly. Next, the control device 6 controls the driving of the first and second motors 41 and 42 to decelerate the movement of the first arm 211 and stop it at the end point P2. Such decelerated movement of the first arm 211 causes the first and second motors 41 and 42 to generate regenerative power.

[0064] Here, the magnitude relationship between the regenerative power generated by the first and second motors 41, 42 is not particularly limited, but for example, it is preferable that the regenerative power generated by the first motor 41 is smaller than the regenerative power generated by the second motor 42. This allows the first and second motors 41, 42 to generate regenerative power in a balanced manner. In particular, it is preferable that the ratio of the regenerative power generated by the first motor 41 to the regenerative power generated by the second motor 42 is 0.4 or more and 0.6 or less, and more preferably 0.5. This makes the above-mentioned effects more pronounced.

[0065] The AC regenerative power generated by the second motor 42 is converted to DC regenerative power by an A / D converter and then stored in the regenerative capacitor 64. Meanwhile, the AC regenerative power generated by the first motor 41 is supplied as AC power to the external device 7 via the control device 6 as shown in FIG. 11. With this configuration, the regenerative power generated by the first and second motors 41, 42 can be distributed in a balanced manner between the control device 6 and the external device 7. This reduces the amount of power discharged by regenerative resistors and the like, allowing more of the regenerative power to be reused. The external device 7 is not particularly limited, and may be, for example, another robot that cooperates with the robot 10.

[0066] In the robot 10 described above, the first motor 41 is driven by the rotation of the first arm 211 to generate regenerative power, and the second motor 42 rotates the first arm 211. The regenerative power generated by the first motor 41 is smaller than the regenerative power generated by the second motor 42, and the driving force of the second motor 42 is smaller than the driving force of the first motor 41. With this configuration, the first arm 211 can be moved smoothly, and the first and second motors 41, 42 can generate regenerative power in a balanced manner.

[0067] As described above, the robot 10 has the control device 6 that controls the driving of the first motor 41, and the regenerative power generated by the second motor 42 is stored in the regenerative capacitor 64 provided in the control device 6, and the regenerative power generated by the first motor 41 is supplied to the external device 7 via the control device 6. With this configuration, the regenerative power generated by the first and second motors 41, 42 can be distributed in a balanced manner. This reduces the amount of power discharged by regenerative resistors and the like, and allows more of the regenerative power to be reused.

[0068] The fourth embodiment can also achieve the same effects as the first embodiment described above.

[0069] While the movable device and robot of the present invention have been described above based on the illustrated embodiments, the present invention is not limited to these, and the configuration of each part can be replaced with any configuration having a similar function. Furthermore, any other configuration may be added to the present invention. Furthermore, the above-described embodiments may be combined as appropriate.

[0070] In addition, in the above-described embodiment, the first member is the base 20 and the second member is the first arm 211, but this is not limiting. For example, the first member may be the first arm 211 and the second member may be the second arm 212. In this case, the configuration of the joint S1 in the above-described embodiment may be applied to the joint S2. Furthermore, the configuration of the joint S1 in the above-described embodiment may be applied to each of the joints S1 and S2.

[0071] Furthermore, in the above-described embodiment, the robot 10 is a SCARA robot, but the robot 10 is not particularly limited and may be, for example, a vertical articulated robot. Furthermore, in the above-described embodiment, the movable device 1 is applied to the robot 10, but the movable device 1 is not particularly limited and may be, for example, a rotation mechanism such as a turntable or index table. Furthermore, it may be an AMR (autonomous mobile transport robot), an AGV (automated guided vehicle), or the like. Furthermore, when the AMR or AGV is driven by a secondary battery (battery), the regenerative power generated by the first motor 41 or the second motor 42 may be converted into DC regenerative power as necessary and then stored in the secondary battery. [Explanation of symbols]

[0072] 1...movable device, 10...robot, 20...base, 21...robot arm, 211...first arm, 212...second arm, 22...work head, 221...spline nut, 222...ball screw nut, 223...spline shaft, 223a...mounting portion, 4A...drive mechanism, 4B...regenerative mechanism, 40...first reducer, 401...roller follower, 402...roller gear cam, 41...first motor, 411...output shaft, 42...second motor, 421...output shaft, 43...first clutch, 44...second 2 clutch, 45...second reducer, 46...power transmission section, 461...first gear, 462...second gear, 50...reduction gear, 51...motor, 6...control device, 61...power input section, 62...converter circuit, 63...drive circuit, 64...regenerative capacitor, 65...discharge resistor, 7...external device, J1...rotating shaft, J2...rotating shaft, J3...rotating shaft, P1...starting point, P2...end point, S1...joint, S2...joint, SH...threshold value, T1...first timing, T2...second timing, T3...third timing, V1...predetermined speed

Claims

1. A first member; a second member that rotates relative to the first member; a first motor that rotates the second member relative to the first member; a second motor that is driven by the rotation of the second member and generates regenerative power.

2. a control device that controls the driving of the first motor; the first motor does not generate the regenerative power, the second motor does not rotate the second member, The movable device according to claim 1 , wherein the regenerative power generated by the second motor is stored in a regenerative capacitor provided in the control device.

3. the first motor is driven by the rotation of the second member to generate regenerative power; the second motor rotates the second member; The regenerative power generated by the first motor is smaller than the regenerative power generated by the second motor, The movable device according to claim 1 , wherein the driving force of the second motor is smaller than the driving force of the first motor.

4. a control device that controls the driving of the first motor; The regenerative power generated by the second motor is stored in a regenerative capacitor provided in the control device, The movable device according to claim 3 , wherein the regenerative power generated by the first motor is supplied to an external device via the control device.

5. the first motor is a servo motor; The movable device according to claim 1 , wherein the second motor is a stepping motor.

6. The movable device according to claim 1 , further comprising a first clutch that switches between a connected state in which the first motor and the second member are connected and a disconnected state in which the first motor and the second member are disconnected.

7. The movable device according to claim 1 , further comprising a second clutch that switches between a connected state in which the second motor and the second member are connected and a disconnected state in which the second motor and the second member are disconnected.

8. The movable device according to claim 7 , wherein the second clutch is switched from the disengaged state to the engaged state when the second member is moving at a reduced speed.

9. 9. A mobile device according to any one of claims 1 to 8, which is a robot.

10. A first member; a second member that rotates relative to the first member; a first motor and a second motor that rotate the second member relative to the first member and are driven by the rotation of the second member to generate regenerative power; The regenerative power generated by the first motor is smaller than the regenerative power generated by the second motor, The robot is characterized in that the driving force of the second motor is smaller than the driving force of the first motor.

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