Rotary Drive System

Abstract

To provide a rotary drive system etc. capable of suppressing upsizing while securing higher torque and high speed.SOLUTION: A drive control system 1 comprises a motor 30, and a control unit for controlling operation of the motor 30. The motor 30 includes a first-system S1 including a plurality of coils, and generating a magnetic field for rotating a rotor; and a second-system S2 including a plurality of coils, and generating a magnetic field for rotating a rotor, which is provided separately from the first-system S1. The control unit comprises a first-drive circuit 21 for operating a first magnetic field generation unit, and a second-drive circuit 22 for operating a second magnetic field generation unit. According to the control unit, both the first-system S1 and the second-system S2 are operably provided in a state where a rotation drive direction of the rotor by the first-system S1, and a rotation drive direction of the rotor by the second-system S2 are made to be identical to each other.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to rotary drive systems and electric motors. [Background technology]

[0002] Electric motors are used as the driving force for robots that walk by moving their legs, such as quadruped walking robots (for example, Patent Document 1).In addition, electric motors are used as the driving force for assist devices that assist humans in walking (for example, Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-117118 [Patent Document 2] Japanese Patent Application Publication No. 2015-058015 Summary of the Invention [Problem to be solved by the invention]

[0004] The electric motors provided in the quadrupedal robots and assist devices described above are required to have higher torque in order to achieve faster response. Simply providing a high-torque electric motor in the quadrupedal robots and assist devices described above would not only increase the size of the electric motor in accordance with the torque, but would also result in an increase in the size of the control system for controlling the operation of the electric motor. Meanwhile, for the electric motors provided in the quadrupedal robots and assist devices described above, the weight of the electric motors becomes a load. Increased size of the electric motors and their control systems leads to increased load on the electric motors. Furthermore, measures to improve the torque performance of electric motors generally impair the high speed (maximum rotation speed) of the electric motors. For these reasons, a configuration has been sought that can increase torque without impairing high speed and suppresses size increase.

[0005] An object of the present disclosure is to provide a rotary drive system and an electric motor that can ensure higher torque and high speed while preventing an increase in size. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the rotary drive system of the present disclosure comprises an electric motor and a control unit that controls the operation of the electric motor, wherein the electric motor is configured as an apparatus in which the weight of the electric motor is included in the weight of the apparatus and the weight of the apparatus acts as a load for the operation of the electric motor, or a configuration in which a person supports part or all of the weight of the electric motor and the weight of the electric motor acts as a load for the operation of the electric motor, and comprises a first magnetic field generation unit that includes a plurality of coils and generates a magnetic field for rotating a rotor, and a second magnetic field generation unit that is provided separately from the first magnetic field generation unit and includes a plurality of coils and generates a magnetic field for rotating the rotor, and the control unit comprises a first drive circuit that operates the first magnetic field generation unit and a second drive circuit that operates the second magnetic field generation unit, and is configured to be able to operate both the first drive circuit and the second drive circuit when the rotational drive direction of the rotor by the first magnetic field generation unit and the rotational drive direction of the rotor by the second magnetic field generation unit are the same.

[0007] Therefore, by operating both the first drive circuit and the second drive circuit while the rotor's rotational drive direction by the first magnetic field generator and the rotor's rotational drive direction by the second magnetic field generator are the same, higher torque can be obtained compared to operating only the first drive circuit or the second drive circuit. Furthermore, while attempts to increase the torque performance of an electric motor generally tend to impair the motor's high speed (maximum rotation speed), the rotary drive system disclosed herein achieves higher torque without affecting the high speed of the electric motor provided by each of the first drive circuit and the second drive circuit. In other words, both torque and high speed of the electric motor can be achieved. Furthermore, the two drive circuits, the first drive circuit that operates the first magnetic field generator and the second drive circuit that operates the second magnetic field generator, only need to have voltage application capabilities appropriate for the size of the coils provided in the magnetic field generators operated by each drive circuit. Therefore, drive circuits that are smaller and generate less heat can be used compared to drive circuits for operating an electric motor with a combined size of the first magnetic field generator and the second magnetic field generator. This allows the entire rotary drive system to be made smaller and lighter. In other words, an electric motor that can obtain torque equivalent to that of an electric motor having the combined size of the first magnetic field generating unit and the second magnetic field generating unit can be controlled by a smaller and lighter control system. As a result, the rotary drive system of the present disclosure can prevent the system from becoming too large while ensuring higher torque and high speed.

[0008] In the rotary drive system of the present disclosure, one of two coils arranged at opposing positions across the rotation axis of the rotor is arranged in the first magnetic field generating unit, and the other is arranged in the second magnetic field generating unit.

[0009] Therefore, the concept of voltage control for suppressing cogging caused by mutual interference between the magnetic field generated by the first magnetic field generating unit and the magnetic field generated by the second magnetic field generating unit can be simplified, making it easier to design the rotary drive system.

[0010] In the rotary drive system of the present disclosure, the first magnetic field generating unit and the second magnetic field generating unit have a U-phase magnetic field generating unit, a V-phase magnetic field generating unit, and a W-phase magnetic field generating unit, and if the total number of coils provided in the first magnetic field generating unit and the second magnetic field generating unit is k and the number of magnetic poles of the rotor is q, the value obtained by dividing k by three times q is not an integer.

[0011] Therefore, it is possible to provide a rotary drive system equipped with a motor that exhibits superior effects, such as reduced torque ripple, compared to fractional slot three-phase AC motors.

[0012] In the rotary drive system of the present disclosure, the coils provided in the first magnetic field generating unit and the second magnetic field generating unit are formed by distributed winding.

[0013] Therefore, it is possible to provide a rotary drive system equipped with an electric motor that can obtain higher torque than an electric motor of the same size configured with a coil using concentrated winding.

[0014] To achieve the above object, the electric motor of the present disclosure is an electric motor that is provided in a configuration in which the weight of the device is included in the weight of the device and the weight of the device acts as a load for the operation of the electric motor, or in which a person supports part or all of the weight of the electric motor and the weight of the electric motor acts as a load for the operation of the electric motor, and is provided with a first magnetic field generating unit that includes a plurality of coils and generates a magnetic field for rotating a rotor, and a second magnetic field generating unit that is provided separately from the first magnetic field generating unit and includes a plurality of coils and generates a magnetic field for rotating a rotor, One of the two coils is provided in the first magnetic field generating unit, and the other is provided in the second magnetic field generating unit. The first magnetic field generating unit and the second magnetic field generating unit have a U-phase magnetic field generating unit, a V-phase magnetic field generating unit, and a W-phase magnetic field generating unit. If the total number of coils provided in the first magnetic field generating unit and the second magnetic field generating unit is k and the number of magnetic poles of the rotor is q, the value obtained by dividing k by three times q is not an integer, and the coils provided in the first magnetic field generating unit and the second magnetic field generating unit are formed by distributed winding.

[0015] Therefore, by operating both the first and second magnetic field generating units while the rotor rotation drive direction by the first and second magnetic field generating units is the same, higher torque can be obtained compared to operating only one of the first and second magnetic field generating units. Furthermore, while attempts to increase the torque performance of a motor generally tend to impair the motor's high-speed (maximum rotation speed), the motor disclosed herein achieves higher torque without affecting the high-speed performance of the motor provided by the first and second drive circuits. In other words, both torque and high-speed performance of the motor can be achieved. Furthermore, the concept of voltage control for suppressing cogging due to mutual interference between the magnetic fields generated by the first and second magnetic field generating units can be simplified, making it easier to design the motor and its control system. Furthermore, the motor can achieve superior benefits of a fractional-slot three-phase AC motor, such as reduced torque ripple. Furthermore, the motor can achieve higher torque compared to a motor of the same size constructed with concentrated winding coils. Furthermore, the two drive circuits, the first drive circuit that operates the first magnetic field generator and the second drive circuit that operates the second magnetic field generator, only need to have voltage application capabilities corresponding to the size of the coils provided in the magnetic field generators operated by each drive circuit. Therefore, a drive circuit that is smaller and generates less heat than a drive circuit for operating an electric motor with a combined size of the first magnetic field generator and the second magnetic field generator can be employed. In other words, the electric motor of the present disclosure makes it easier to reduce the size and weight of the control system. Therefore, configurations equipped with the electric motor of the present disclosure can be more easily reduced in size and weight. From the above, the electric motor of the present disclosure can ensure higher torque and high speed while suppressing size increase. [Effects of the Invention]

[0016] According to the present disclosure, it is possible to suppress an increase in size while ensuring higher torque and high speed. [Brief explanation of the drawings]

[0017] [Figure 1]FIG. 1 is a block diagram showing the main configuration of the drive control system. [Figure 2] FIG. 2 is a schematic diagram showing an example of the configuration of the first system in the case of star connection. [Figure 3] FIG. 3 is a schematic diagram showing an example of the configuration of the second system in the case of star connection. [Figure 4] FIG. 4 is a schematic diagram showing an example of the relationship between the rotor and the stator of an electric motor. [Figure 5] FIG. 5 is a schematic diagram showing that a copper wire is wound around the outer periphery of the teeth T in a clockwise direction. [Figure 6] FIG. 6 is a schematic diagram showing that a copper wire is wound around the outer periphery of the teeth T in a counterclockwise direction. [Figure 7] FIG. 7 is a schematic diagram showing an example of the winding direction and connection relationship of copper wires wound around the teeth of a stator. [Figure 8] FIG. 8 is a block diagram showing the main configuration of the drive control system. [Figure 9] FIG. 9 is a schematic diagram showing an example of the main configuration of a walking robot. [Figure 10] FIG. 10 is a schematic diagram showing an example of the main configuration of a walking robot. [Figure 11] FIG. 11 is a schematic diagram showing an example of the main configuration of the assist device. [Figure 12] FIG. 12 is a schematic graph showing an electric motor and the relationship between the rotation speed and torque exhibited by the electric motor. [Figure 13] FIG. 13 is a schematic diagram showing an example of the configuration of an electric motor that can be employed in the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments will be described with reference to the drawings, but the present invention is not limited thereto. The requirements of each embodiment described below can be combined as appropriate. In addition, some components may not be used.

[0019] 1 is a block diagram showing the main configuration of a drive control system 1. The drive control system 1 includes an electric motor 30 and controls the driving of the electric motor 30. The drive control system 1 includes a control device 10, a first drive circuit 21, a second drive circuit 22, the electric motor 30, a position sensor 40, and a power supply 50.

[0020] The control device 10 controls the operation of the electric motor 30 in a configuration in which the weight of the electric motor 30 is included in the weight of the device and the weight of the device acts as a load for the operation of the electric motor 30, or in a configuration in which a human supports part or all of the weight of the electric motor 30 and the weight of the electric motor 30 acts as a load for the operation of the electric motor 30. An example of a configuration in which the weight of the electric motor 30 is included in the weight of the device and the weight of the device acts as a load for the operation of the electric motor 30 is, for example, a walking robot 100, which will be described later with reference to Figures 9 and 10. An example of a configuration in which a human supports part or all of the weight of the electric motor 30 and the weight of the electric motor 30 acts as a load for the operation of the electric motor 30 is, for example, an assist device 200, which will be described later with reference to Figure 11.

[0021] The control device 10 is connected to a first drive circuit 21 via a first system signal line 11. The control device 10 is also connected to a second drive circuit 22 via a second system signal line 12. The first drive circuit 21 controls the operation of the electric motor 30 via a first system S1 of the electric motor 30 under the control of the control device 10. The second drive circuit 22 controls the operation of the electric motor 30 via a second system S2 of the electric motor 30 under the control of the control device 10. The first drive circuit 21 and the second drive circuit 22 are driver circuits for the three-phase AC motor.

[0022] The first system S1 includes a U-phase magnetic field generator U1, a V-phase magnetic field generator V1, and a W-phase magnetic field generator W1. Each of the U-phase magnetic field generator U1, the V-phase magnetic field generator V1, and the W-phase magnetic field generator W1 has one or more coils.

[0023] The U-phase magnetic field generator U1, V-phase magnetic field generator V1, and W-phase magnetic field generator W1 shown in FIG. 1 are connected to the first drive circuit 21 by a so-called star connection. Specifically, one end of the windings of the coils of the U-phase magnetic field generator U1, V-phase magnetic field generator V1, and W-phase magnetic field generator W1 is connected to the neutral point N1. The other end of the windings of the coils of the U-phase magnetic field generator U1 is connected to the first drive circuit 21 via a wiring LU1. The other end of the windings of the coils of the V-phase magnetic field generator V1 is connected to the first drive circuit 21 via a wiring LV1. The other end of the windings of the coils of the W-phase magnetic field generator W1 is connected to the first drive circuit 21 via a wiring LW1.

[0024] The second system S2 includes a U-phase magnetic field generator U2, a V-phase magnetic field generator V2, and a W-phase magnetic field generator W2. Each of the U-phase magnetic field generator U2, the V-phase magnetic field generator V2, and the W-phase magnetic field generator W2 has one or more coils.

[0025] The U-phase magnetic field generator U2, the V-phase magnetic field generator V2, and the W-phase magnetic field generator W2 shown in FIG. 1 are connected to the second drive circuit 22 by a so-called star connection. Specifically, one end of the windings of the coils of the U-phase magnetic field generator U2, the V-phase magnetic field generator V2, and the W-phase magnetic field generator W2 is connected to the neutral point N2. The other end of the windings of the coils of the U-phase magnetic field generator U2 is connected to the second drive circuit 22 via a wiring LU2. The other end of the windings of the coils of the V-phase magnetic field generator V2 is connected to the second drive circuit 22 via a wiring LV2. The other end of the windings of the coils of the W-phase magnetic field generator W2 is connected to the second drive circuit 22 via a wiring LW2.

[0026] As described above, the first system S1 and the second system S2 each have coils of a so-called three-phase AC motor. When the first system S1 is operating, the U-phase magnetic field generator U1, the V-phase magnetic field generator V1, and the W-phase magnetic field generator W1 are each supplied with single-phase AC currents that are 120° out of phase with each other. When the second system S2 is operating, the U-phase magnetic field generator U2, the V-phase magnetic field generator V2, and the W-phase magnetic field generator W2 are each supplied with single-phase AC currents that are 120° out of phase with each other.

[0027] The electric motor 30 is provided with a position sensor 40. The position sensor 40 outputs a signal indicating the rotation angle of the rotor 31 (see FIG. 4) of the electric motor 30. The position sensor 40 outputs the signal indicating the rotation angle of the rotor 31 to the first drive circuit 21 via a wiring 41. The position sensor 40 also outputs the signal indicating the rotation angle of the rotor 31 to the second drive circuit 22 via a wiring 42.

[0028] The drive control system 1 also has a power supply 50. The power supply 50 supplies power to each component of the drive control system 1. While Fig. 1 illustrates wiring 51 connecting the power supply 50 with the control device 10, the first drive circuit 21, and the second drive circuit 22, this is not limiting, and other components in the drive control system 1 that require power for operation also operate by receiving power from the power supply 50 in the same way.

[0029] The control device 10 is capable of adopting both a first mode in which only one of the first system S1 and the second system S2 is operated, and a second mode in which both the first system S1 and the second system S2 are operated. In the first mode, the control device 10 operates either the first drive circuit 21 or the second drive circuit 22, but does not operate the other. In the second mode, the first drive circuit 21 and the second drive circuit 22 are controlled in synchronization with each other in accordance with the rotation angle of the rotor 31 indicated by the output of the position sensor 40, so that the driving force due to the magnetic flux distribution of the first system S1 and the driving force due to the magnetic flux distribution of the second system S2 are in the same rotation direction.

[0030] In the unlikely event that an abnormality occurs in either the first system S1 or the second system S2, such as the system not operating or not being synchronized with the other system, the control device 10 may turn off the operation of the system in which the abnormality occurred and maintain rotation using only the other system. Such control can be achieved, for example, based on a combination of drive control by the first drive circuit 21 and the second drive circuit 22 and feedback from the position sensor 40.

[0031] 2 is a schematic diagram showing a configuration example of the first system S1 in the case of star connection. As shown in FIG. 2, the U-phase magnetic field generator U1 includes, for example, coils U1A, U1B, and U1C connected in series from the neutral point N1 side toward the wiring LU1 side. The V-phase magnetic field generator V1 includes, for example, coils V1A, V1B, and V1C connected in series from the neutral point N1 side toward the wiring LV1 side. The W-phase magnetic field generator W1 includes, for example, coils W1A, W1B, and W1C connected in series from the neutral point N1 side toward the wiring LW1 side.

[0032] 3 is a schematic diagram showing a configuration example of the second system S2 in the case of star connection. As shown in FIG. 3, the U-phase magnetic field generator U2 includes, for example, coils U2A, U2B, and U2C connected in series from the neutral point N2 side toward the wiring LU2 side. The V-phase magnetic field generator V2 includes, for example, coils V2A, V2B, and V2C connected in series from the neutral point N2 side toward the wiring LV2 side. The W-phase magnetic field generator W2 includes, for example, coils W2A, W2B, and W2C connected in series from the neutral point N2 side toward the wiring LW2 side.

[0033] FIG. 4 is a schematic diagram showing an example of the relationship between the rotor 31 and the stator 32 of the electric motor 30. The rotor 31 shown in FIG. 4 is a magnet with 22 magnetic poles, 11 north poles and 11 south poles, arranged in an annular shape, and is rotatable around a rotation axis C. Specifically, the annular rotor 31 shown in FIG. 4 is integrally formed with a disk-shaped support (not shown). The support is rotatable around the rotation axis C. The north poles and south poles of the rotor 31 are alternately arranged along the circumferential direction of the ring. The stator 32 shown in FIG. 4 is provided inside the ring of the rotor 31. Thus, the electric motor 30 shown in FIG. 4 is a so-called outer rotor electric motor. In the case of an inner rotor electric motor, the rotor 31 is arranged inside an inner peripheral portion 32a of the stator 32. The stator 32 has a plurality of teeth T (see FIGS. 5 and 6) protruding toward the outer periphery. 4 shows a case where the number of teeth T that the stator 32 has is 18. A coil is provided on each tooth T. That is, the electric motor 30 shown in FIG. 4 is an electric motor with 22 poles and 18 slots.

[0034] In FIG. 4, the teeth are designated with a combination of the letter T and a number. Specifically, one of the 18 teeth is designated with the symbol T1, and the numbers at the end of the symbols of the other teeth arranged in order from the tooth designated with the symbol T1 in the counterclockwise direction P around the rotation axis C are incremented. Therefore, the stator 32 shown in FIG. 4 has teeth T1, T2, ..., T18. When a tooth is referred to as T, it refers to any of the teeth T1, T2, ..., T18.

[0035] FIG. 5 is a schematic diagram showing that copper wire is wound around the outer periphery of the teeth T in a clockwise direction V1. FIG. 6 is a schematic diagram showing that copper wire is wound around the outer periphery of the teeth T in a counterclockwise direction V2. Note that FIGS. 5 and 6 show the teeth T viewed from the outer periphery of the stator 32 as the front side and the rotation axis C side as the back side. As shown in FIGS. 5 and 6, the copper wire constituting the coil wound around each tooth T is wound around the teeth T in a clockwise direction V1 or a counterclockwise direction V2. Note that FIGS. 5 and 6 show an example in which the shape of the teeth T when viewed from the outer periphery side is rectangular, but the shape of the teeth T is not limited to this and can be changed as appropriate.

[0036] FIG. 7 is a schematic diagram showing an example of the winding direction and connection relationship of the copper wire wound around the teeth T of the stator 32. In FIG. 7, the symbol a is attached to one end of the copper wire wound around the teeth T. When the starting point a is written, it refers to one end of the copper wire. Also in FIG. 7, the symbol Tn is attached to the tooth T on which the first coil is formed by the copper wire when winding of the copper wire starts from the starting point a. Also in FIG. 7, the symbols T(n+1), T(n+2), ..., T(n+17) are attached to the other teeth arranged in order in the counterclockwise direction P from the tooth attached with the symbol Tn. Note that in the explanation with reference to FIG. 7, the direction "from the inside to the outside" refers to the direction "from the rotation axis C side toward the outer periphery of the stator 32."

[0037] n is a natural number between 1 and 18. If n is 2 or greater, some or all of (n+1), (n+2), ..., (n+17) are natural numbers greater than 18. Any natural number greater than 18 among (n+1), (n+2), ..., (n+17) is replaced with the value obtained by subtracting 18 from the natural number.

[0038] First, a copper wire is wound from the inside to the outside along the tooth Tn. This forms a coil 1A on the tooth Tn. Next, the other end of the copper wire extending from the coil 1A is routed to the tooth T(n+1). Therefore, the copper wire continues from symbol b to symbol c in FIG. 7. The copper wire routed to the tooth T(n+1) is then wound from the inside to the outside along the tooth T(n+1). This forms a coil 1B on the tooth T(n+1). The winding direction of the copper wire forming the coil 1A is different from the winding direction of the copper wire forming the coil 1B. FIG. 7 illustrates a case where the winding direction of the copper wire forming the coil 1A is clockwise V1 (see FIG. 5) and the winding direction of the copper wire forming the coil 1B is counterclockwise V2 (see FIG. 6).

[0039] Next, the other end of the copper wire extending from coil 1B is routed to tooth T(n+5). Therefore, the copper wire continues from symbol c to symbol d shown in FIG. 7. The copper wire routed to tooth T(n+5) is wound from the inside to the outside along tooth T(n+5). In this way, coil 1C is provided on tooth T(n+5). The winding direction of the copper wire forming coil 1B is different from the winding direction of the copper wire forming coil 1C.

[0040] Next, the other end of the copper wire extending from coil 1C is routed to tooth T(n+9), for example, from the position indicated by symbol e. Therefore, the copper wire continues from symbol e to symbol f in FIG. 7. The copper wire also continues from symbol d to symbol e. The copper wire routed to tooth T(n+9) is wound around tooth T(n+9) from the inside to the outside along tooth T(n+9). In this way, coil 2C is provided on tooth T(n+9). The winding direction of the copper wire forming coil 1C is different from the winding direction of the copper wire forming coil 2C.

[0041] Next, the other end of the copper wire extending from coil 2C is routed to tooth T(n+10). Therefore, the copper wire continues from symbol f to symbol g shown in FIG. 7. The copper wire routed to tooth T(n+10) is wound around tooth T(n+10) from the inside to the outside. In this way, coil 2B is provided on tooth T(n+10). The winding direction of the copper wire forming coil 2C is different from the winding direction of the copper wire forming coil 2B.

[0042] Next, the other end of the copper wire extending from the coil 2B is routed to the tooth T(n+14), for example, from the position indicated by the symbol h. Therefore, the copper wire continues from the symbol h to the symbol i in FIG. 7. The copper wire also continues from the symbol g to the symbol h. The copper wire routed to the tooth T(n+14) is wound around the tooth T(n+14) from the inside to the outside. This results in the coil 2A being attached to the tooth T(n+14). The winding direction of the copper wire forming the coil 2B is different from the winding direction of the copper wire forming the coil 2A. In FIG. 7, the other end of the copper wire wound around the tooth T(n+14) is indicated by the symbol j. The term "end point j" refers to the other end of the copper wire.

[0043] Of the coils 1A, 1B, 1C, 2C, 2B, and 2A wound in this manner, the copper wire forming coils 1A, 1C, and 2B is wound in the same direction, and the copper wire forming coils 1B, 2C, and 2A is wound in the same direction.

[0044] The continuous copper wire forming coils 1A, 1B, 1C, 2C, 2B, and 2A is cut at a cutting position CU between symbols e and f. This results in two coil groups: a coil group (first coil group) including coils 1A, 1B, and 1C, and a coil group (second coil group) including coils 2A, 2B, and 2C. In Figure 7, of the ends of the copper wire resulting from cutting the copper wire at the cutting position CU, one end that is continuous with coil 1C is designated as end E1, and the other end that is continuous with coil 2C is designated as end E2.

[0045] When two coils facing each other across the rotation axis C, i.e., two coils whose arrangement angles around the rotation axis C differ by 180°, are considered as a pair of coils, the coils included in the first coil group and the coils included in the second coil group include three pairs of coils. Specifically, coil 1A and coil 2C are considered as a pair of coils. The number of turns of the copper wire forming coil 1A is the same as the number of turns of the copper wire forming coil 2C. Coil 1B and coil 2B are also considered as a pair of coils. The number of turns of the copper wire forming coil 1B is the same as the number of turns of the copper wire forming coil 2B. Coil 1C and coil 2A are also considered as a pair of coils. The number of turns of the copper wire forming coil 1C is the same as the number of turns of the copper wire forming coil 2A. In the embodiment, the number of turns of the copper wire forming each of coils 1A, 1B, 1C, 2C, 2B, and 2A is all the same.

[0046] The coils U1A, U1B, U1C, U2C, U2B, and U2A described with reference to FIGS. 2 and 3 are formed from a continuous copper wire described with reference to FIG. 7 and are arranged as shown in FIG. 4. Specifically, a drive control system (see FIG. 7) is formed on tooth T1 to form coil U1A shown in FIG. 4. A coil 1B (see FIG. 7) is formed on tooth T2 to form coil U1B shown in FIG. 4. A coil 1C (see FIG. 7) is formed on tooth T6 to form coil U1C shown in FIG. 4. A coil 2C (see FIG. 7) is formed on tooth T10 to form coil U2C shown in FIG. 4. A coil 2B (see FIG. 7) is formed on tooth T11 to form coil U2B shown in FIG. 4. A coil 2A (see FIG. 7) is formed on tooth T15 to form coil U2A shown in FIG. 4. Therefore, the value of n in the formation of coils U1A, U1B, U1C, U2C, U2B, and U2A is 1.

[0047] The copper wires forming coils U1A, U1B, U1C, U2C, U2B, and U2A are cut at cutting position CU (see FIG. 7). Here, starting point a is connected to neutral point N1, and end E1 is connected to wiring LU1, thereby establishing the relationship between the U-phase magnetic field generator U1, neutral point N1, and wiring LU1 shown in FIG. 2. Furthermore, ending point j is connected to neutral point N2, and end E2 is connected to wiring LU2, thereby establishing the relationship between the U-phase magnetic field generator U2, neutral point N2, and wiring LU2 shown in FIG. 3.

[0048] The coils V1A, V1B, V1C, V2C, V2B, and V2A described with reference to FIGS. 2 and 3 are formed from a continuous copper wire described with reference to FIG. 7 and are arranged as shown in FIG. 4. Specifically, the drive control system (see FIG. 7) is formed on tooth T4 to form coil V1A shown in FIG. 4. The coil 1B (see FIG. 7) is formed on tooth T5 to form coil V1B shown in FIG. 4. The coil 1C (see FIG. 7) is formed on tooth T13 to form coil V1C shown in FIG. 4. The coil 2C (see FIG. 7) is formed on tooth T14 to form coil V2C shown in FIG. 4. The coil 2B (see FIG. 7) is formed on tooth T15 to form coil V2B shown in FIG. 4. The coil 2A (see FIG. 7) is formed on tooth T18 to form coil V2A shown in FIG. 4. Therefore, the value of n in the formation of the coils V1A, V1B, V1C, V2C, V2B, and V2A is 4.

[0049] The copper wires forming coils V1A, V1B, V1C, V2C, V2B, and V2A are cut at cutting position CU (see FIG. 7). Here, starting point a is connected to neutral point N1, and end E1 is connected to wire LV1, thereby establishing the relationship between the V-phase magnetic field generator V1, neutral point N1, and wire LV1 shown in FIG. 2. Furthermore, ending point j is connected to neutral point N2, and end E2 is connected to wire LV2, thereby establishing the relationship between the V-phase magnetic field generator V2, neutral point N2, and wire LV2 shown in FIG. 3.

[0050] The coils W1A, W1B, W1C, W2C, W2B, and W2A described with reference to FIGS. 2 and 3 are formed from a continuous copper wire described with reference to FIG. 7 and are arranged as shown in FIG. 4. Specifically, a drive control system (see FIG. 7) is formed on tooth T7 to form coil W1A shown in FIG. 4. A coil 1B (see FIG. 7) is formed on tooth T8 to form coil W1B shown in FIG. 4. A coil 1C (see FIG. 7) is formed on tooth T12 to form coil W1C shown in FIG. 4. A coil 2C (see FIG. 7) is formed on tooth T16 to form coil W2C shown in FIG. 4. A coil 2B (see FIG. 7) is formed on tooth T17 to form coil W2B shown in FIG. 4. A coil 2A (see FIG. 7) is formed on tooth T3 to form coil W2A shown in FIG. 4. Therefore, the value of n in the formation of coils W1A, W1B, W1C, W2C, W2B, and W2A is 7. When n=7, tooth T(n+14) in FIG. 7 corresponds to tooth T3 in FIG. 4 (7+14-18=3).

[0051] The copper wires forming coils W1A, W1B, W1C, W2C, W2B, and W2A are cut at cutting position CU (see FIG. 7). Here, starting point a is connected to neutral point N1, and end E1 is connected to wiring LW1, thereby establishing the relationship between the W-phase magnetic field generator W1, neutral point N1, and wiring LW1 shown in FIG. 2. Furthermore, ending point j is connected to neutral point N2, and end E2 is connected to wiring LW2, thereby establishing the relationship between the W-phase magnetic field generator W2, neutral point N2, and wiring LW2 shown in FIG. 3.

[0052] Although exemplary configurations of the drive control system 1 and the electric motor 30 have been described above with reference to FIGS. 1 to 7, the configurations of the drive control system and the electric motor according to the present disclosure are not limited to these.

[0053] FIG. 8 is a block diagram showing the main configuration of the drive control system. The drive control system includes an electric motor 35 and controls the driving of the electric motor 35. The drive control system 1 includes a first control device 13 and a second control device 14. The first control device 13 is connected to a first drive circuit 23. The second control device 14 is connected to a second drive circuit 24. The first drive circuit 23 controls the operation of the electric motor 35 by a first system S1 of the electric motor 35 under the control of the first control device 13. The second drive circuit 24 controls the operation of the electric motor 35 by a second system S2 of the electric motor 35 under the control of the second control device 14.

[0054] Separate controllers may be provided for the first system and the second system S2 of the electric motor 35, such as the first controller 13 and the second controller 14. The first controller 13 has the same configuration as the controller 10, except that the object of control is limited to the first drive circuit 23. The second controller 14 has the same configuration as the controller 10, except that the object of control is limited to the second drive circuit 24.

[0055] The U-phase magnetic field generator U1, V-phase magnetic field generator V1, and W-phase magnetic field generator W1 of the first system S1 of the electric motor 35 are connected in a so-called delta connection. Similarly, the U-phase magnetic field generator U2, V-phase magnetic field generator V2, and W-phase magnetic field generator W2 of the second system S2 of the electric motor 35 are connected in a so-called delta connection. The first drive circuit 23 and the second drive circuit 24 are driver circuits for a three-phase AC motor compatible with the delta connection.

[0056] In the configuration shown in FIG. 8 , one end of the coil of the U-phase magnetic field generator U1 and one end of the coil of the W-phase magnetic field generator W1 are connected to the first drive circuit 23 via wiring L11. One end of the coil of the V-phase magnetic field generator V1 and the other end of the coil of the W-phase magnetic field generator W1 are connected to the first drive circuit 23 via wiring L12. The other end of the coil of the U-phase magnetic field generator U1 and the other end of the coil of the V-phase magnetic field generator V1 are connected to the first drive circuit 23 via wiring L13. One end of the coil of the U-phase magnetic field generator U2 and one end of the coil of the W-phase magnetic field generator W2 are connected to the second drive circuit 24 via wiring L21. One end of the coil winding of the V-phase magnetic field generator V2 and the other end of the coil winding of the W-phase magnetic field generator W2 are connected to the second drive circuit 24 via wiring L22. The other end of the coil winding of the U-phase magnetic field generator U2 and the other end of the coil winding of the V-phase magnetic field generator V2 are connected to the second drive circuit 24 via wiring L23.

[0057] 8, the position sensor 40 outputs a signal indicating the rotation angle of the rotor of the electric motor 35 to the first control device 13 via a wiring 43. The position sensor 40 also outputs a signal indicating the rotation angle of the rotor of the electric motor 35 to the second control device 14 via a wiring 44. In this manner, the signal from the position sensor 40 may be fed back to the control devices (first control device 13, second control device 14) that control the operation of the driver circuits (first drive circuit 23, second drive circuit 24). The first control device 13 and the second control device 14 operate cooperatively based on feedback from the position sensor 40, and, like the control device 10 described above, are configured to be switchable between a first mode and a second mode.

[0058] 8 may include three coils, or may include two or less coils, or may include four or more coils, similar to the specific configurations of U-phase magnetic field generator U1, V-phase magnetic field generator V1, W-phase magnetic field generator W1, U-phase magnetic field generator U2, V-phase magnetic field generator V2, and W-phase magnetic field generator W2 described with reference to Figures 2 and 3. Although not shown, the drive control system shown in Figure 8 also includes a power supply that supplies power to each component, similar to power supply 50 described above.

[0059] An example of an apparatus in which a drive control system according to the present disclosure is employed, such as a drive control system, will be described below with reference to FIGS.

[0060] 9 and 10 are schematic diagrams showing an example of the main configuration of a walking robot 100. The walking robot 100 is a quadruped walking robot that walks by operating four legs 70 that are rotatably provided with respect to a body 60. In FIGS. 9 and 10, the direction in which two of the four legs 70 are aligned (front-to-back direction) without the body 60 between them is defined as a first direction Dx, and the direction in which two opposing legs 70 face each other with the body 60 between them (left-to-right direction) is defined as a second direction Dy. The direction perpendicular to the first direction Dx and the second direction Dy is defined as a third direction Dz.

[0061] The body 60 and the legs 70 are connected via the actuator 3. The actuator 3 is an actuator that is provided so as to be able to control the relative rotation angle between the body 60 and the legs 70. The operation of the actuator 3 is controlled by controlling the rotation angle of an electric motor 30 (or an electric motor 35) provided within the actuator 3. Of the components provided in the drive control system 1 (or the drive control system), parts other than the electric motor 30 may be provided within the actuator 3 or may be provided within the body 60.

[0062] The leg 70 has an upper leg portion 71 and a lower leg portion 72. The upper leg portion 71 and the lower leg portion 72 are connected via a joint portion 4. The joint portion 4 may be configured to be able to passively change the rotation angle of the lower leg portion 72 relative to the upper leg portion 71 by an elastic member such as a spring, or may be configured to be able to actively change the rotation angle of the lower leg portion 72 relative to the upper leg portion 71 by controlling the rotation angle of the electric motor 30 (or electric motor 35) by the drive control system 1 (or drive control system), similar to the actuator 3.

[0063] 11 is a schematic diagram showing an example of the main configuration of the assist device 200. The assist device 200 is attached to the lower limbs RE and waist WE of a person, and operates to assist the person in standing and walking.

[0064] The assisting device 200 has actuators 5, 6, and 7, connecting portions 91, 92, 93, 94, and 95, and fixing portions 96, 97, 98, and 99. Actuator 5 is provided at a position corresponding to the hip joint. Actuator 6 is provided at a position corresponding to the knee joint of the lower limb RE. Actuator 7 is provided at a position corresponding to the joint near the ankle (ankle joint) of the lower limb RE. Connecting portions 91 and 92 connect actuator 5 to actuator 6. Connecting portions 93 and 94 connect actuator 6 to actuator 7. Connecting portion 95 connects actuator 7 to fixing portion 96. Fixing portion 96 fixes the actuator 7 side of the assisting device 200 to the heel of the lower limb RE. Fixing portion 97 fixes the actuator 5 side of the assisting device 200 to the waist WE. Fixing portion 98 fixes connecting portion 91 to the thigh of the lower limb RE. The fixing part 99 fixes the connecting part 93 to the lower leg RE.

[0065] Actuator 5 is an actuator provided so as to be able to control the rotation angle of connecting portion 91 relative to fixed portion 97. Actuator 6 is an actuator provided so as to be able to control the rotation angle of fixed portion 99 relative to connecting portion 92. Actuator 7 is an actuator provided so as to be able to control the rotation angle of connecting portion 95 relative to connecting portion 94. The operation of each of actuators 5, 6, and 7 is controlled by controlling the rotation angle of electric motor 30 (or electric motor 35) provided in each of actuators 5, 6, and 7. Of the components provided in drive control system 1 (or the drive control system), parts other than electric motor 30 may be provided within each actuator, or may be provided inside the housing of a connecting portion such as connecting portions 91 and 93.

[0066] The actuators 5, 6, and 7 are part of the assist device 200. Therefore, the weight of the actuators 5, 6, and 7 is part of the total weight of the assist device 200. Furthermore, the weight of the assist device 200 becomes a load for the person using the assist device 200. Furthermore, the weight of the assist device 200 is part of the total weight of the object to be assisted by the assist device 200. Therefore, it is desirable that the weight of the actuators 5, 6, and 7 and the drive control system 1 (or the drive control system) that controls the operation of the electric motor 30 (or the electric motor 35) provided in the actuators 5, 6, and 7 be as light as possible.

[0067] Fig. 12 is a schematic graph showing the relationship between the rotation speed and torque of the electric motor 30 and the electric motor 35. In the graph of Fig. 12, the vertical axis represents the torque (T) of the electric motor 30 and the electric motor 35, and the horizontal axis represents the rotation speed (N) of the electric motor 30 and the electric motor 35. The relationship between the rotation speed and torque of the electric motor 30 and the electric motor 35 when only one of the first system S1 or the second system S2 is operated is shown, for example, in graphs G11 and G12. The relationship between the rotation speed and torque of the electric motor 30 and the electric motor 35 when both the first system S1 and the second system S2 are operated is shown, for example, in graphs G21 and G22.

[0068] As shown in graphs G11 and G21, the electric motors 30 and 35 exert a substantially constant torque (T) until the rotation speed (N) exceeds a certain threshold value TH. On the other hand, once the threshold value TH is exceeded, as shown in graphs G12 and G22, the torque (T) decreases as the rotation speed (N) increases. As shown by the difference between graphs G11 and G12 and graphs G21 and G22, by operating both the first system S1 and the second system S2, the torque (T) of the electric motors 30 and 35 when the rotation speed (N) is below the threshold value TH is doubled compared to when only one of the first system S1 and the second system S2 is operated. To illustrate this doubling of torque (T), FIG. 12 shows that the difference in torque (T) between graphs G21 and G11 corresponds to the height CT of the torque (T) of graph G11.

[0069] If a typical three-phase AC motor with a single system were to generate the torque (T) corresponding to graph G21, a driver circuit capable of applying a large voltage corresponding to the torque (T) would be required. In contrast, in a three-phase AC motor with a first system S1 and a second system S2, such as motor 30 and motor 35, employed in an embodiment of the present disclosure, separate driver circuits (first drive circuit 21 and second drive circuit 22, or first drive circuit 23 and second drive circuit 24) are provided for the first system S1 and the second system S2, respectively. The first system S1 and the second system S2 can each generate the torque (T) shown in graph G11, and the torque (T) shown in graph G11 can be generated by operating both the first system S1 and the second system S2. The applied voltage required to generate the torque (T) corresponding to graph G11 in a single system is naturally lower than the applied voltage required to generate the torque (T) corresponding to graph G21 in a single system. That is, according to the embodiment, a driver circuit requiring a lower applied voltage can be employed compared to the applied voltage required for one driver circuit in a normal three-phase AC motor. In this way, a driver circuit requiring a lower applied voltage that can be employed in the embodiment is cheaper, more readily available, smaller, generates less heat, and is lighter in weight than a driver circuit requiring a higher applied voltage.

[0070] In particular, lower heat generation means that the heat dissipation unit for cooling the driver circuit can be smaller in size, contributing to further weight reduction. Therefore, in an embodiment in which both the first system S1 and the second system S2 are operable, such as the electric motors 30 and 35, the total weight of the entire control system, such as the drive control system 1 or the drive control system, is significantly lighter than the total weight of the entire control system when a similar torque is to be generated by a single system.

[0071] A lighter control system such as the drive control system 1 or an entire control system contributes to a lighter weight of the device itself, such as the walking robot 100 or the assist device 200. Here, the actuators (such as actuator 3) provided in the walking robot 100 and the actuators (such as actuators 5, 6, and 7) provided in the assist device 200 need to generate torque (T) to move weights including their own weight. Therefore, a lighter control system such as the drive control system 1 or an entire control system such as the drive control system can more easily alleviate the torque performance requirements required of the actuators (such as actuator 3) provided in the walking robot 100 and the actuators (such as actuators 5, 6, and 7) provided in the assist device 200. Therefore, according to the embodiment, the actuators (such as actuator 3) provided in the walking robot 100 and the actuators (such as actuators 5, 6, and 7) provided in the assist device 200 can be designed under conditions of more relaxed required torque performance. Furthermore, compared to configurations employing electric motors with the same torque performance in a single system, it is possible to provide a walking robot 100 or an assist device 200 that is lighter overall and has better acceleration response.

[0072] The above description assumes the electric motor 30 and the electric motor 35 described with reference to FIGS. 1 to 8 , but the configuration according to the present disclosure is not limited thereto. For example, while the U-phase magnetic field generator U1, the V-phase magnetic field generator V1, the W-phase magnetic field generator W1, the U-phase magnetic field generator U2, the V-phase magnetic field generator V2, and the W-phase magnetic field generator W2 described with reference to FIGS. 2 to 7 each include three coils, each may include two or fewer coils or four or more coils. However, the number of coils (m) included in each of the U-phase magnetic field generator U1, the V-phase magnetic field generator V1, the W-phase magnetic field generator W1, the U-phase magnetic field generator U2, the V-phase magnetic field generator V2, and the W-phase magnetic field generator W2 is the same. m is a natural number. Furthermore, the U-phase magnetic field generator U1 and the U-phase magnetic field generator U2 each include m pairs of coils. Furthermore, the V-phase magnetic field generator V1 and the V-phase magnetic field generator V2 each include m pairs of coils. Furthermore, the W-phase magnetic field generator W1 and the W-phase magnetic field generator W2 each include m pairs of coils.

[0073] The relationship between the number of coils (18) wound on the stator 32 of the electric motor 30 and the number of poles (22) on the rotor 31 indicates that the electric motor 30 has so-called fractional slots. While the electric motor employed in the embodiments has fractional slots, which facilitates improving torque performance relative to weight, the electric motor employed in the embodiments may have integer slots. Whether the electric motor has fractional slots or integer slots, the number of rotor poles is not limited to 22 and is arbitrary. However, the number of slots, i.e., the number of coils, in the electric motor employed in the embodiments is a multiple of 6. Furthermore, while the coils wound on the stator 32 of the electric motor 30 described above are wound using so-called distributed winding, the coil winding method in the electric motor employed in the embodiments is not limited to this. An electric motor having coils wound using so-called concentrated winding may also be employed in the embodiments.

[0074] FIG. 13 is a schematic diagram showing a configuration example of an electric motor 300 that can be employed in the embodiment. The electric motor 300 shown in FIG. 13 has a rotor 310 that is a two-pole magnet and a stator 320 that has six slots. That is, the electric motor 300 is a so-called integer-slot electric motor. Furthermore, in the electric motor 300, each of the U-phase magnetic field generator U1, V-phase magnetic field generator V1, W-phase magnetic field generator W1, U-phase magnetic field generator U2, V-phase magnetic field generator V2, and W-phase magnetic field generator W2 has one coil, and the coil is provided by concentrated winding. The drive control system 1 or the drive control system described above can also be realized by replacing the electric motor 30 in FIG. 1 or the electric motor 35 in FIG. 8 with the electric motor 300.

[0075] As described above, a rotary drive system (e.g., drive control system 1 or drive control system) according to an embodiment includes an electric motor (e.g., electric motor 30, electric motor 35, or electric motor 300) and a control unit that controls the operation of the electric motor. The electric motor is provided in a device whose weight is included in the weight of the device and whose weight acts as a load for the operation of the electric motor (e.g., walking robot 100), or in a device whose weight is partially or entirely supported by a human and whose weight acts as a load for the operation of the electric motor (e.g., assist device 200). The electric motor includes a first magnetic field generation unit (e.g., first system S1) that includes multiple coils (e.g., coil U1A, etc.) and generates a magnetic field for rotating a rotor (e.g., rotor 31), and a second magnetic field generation unit (e.g., second system S2) that is provided separately from the first magnetic field generation unit, includes multiple coils, and generates a magnetic field for rotating the rotor. The control unit includes a first drive circuit (e.g., first drive circuit 21 or first drive circuit 23) that operates the first magnetic field generation unit, and a second drive circuit (e.g., second drive circuit 22 or second drive circuit 24) that operates the second magnetic field generation unit. The control unit is configured to be able to operate both the first drive circuit and the second drive circuit in a state where the direction in which the rotor is rotationally driven by the first magnetic field generation unit and the direction in which the rotor is rotationally driven by the second magnetic field generation unit are the same.

[0076] Therefore, by operating both the first drive circuit (e.g., first drive circuit 21 or 23) and the second drive circuit (e.g., second drive circuit 22 or 24) while the rotor rotation drive direction by the first magnetic field generating unit (e.g., first system S1) and the second magnetic field generating unit (e.g., second system S2) are the same, higher torque can be obtained compared to operating only one of the first drive circuit and the second drive circuit. Furthermore, while attempts to increase the torque performance of an electric motor generally tend to impair the high speed (maximum rotation speed) of the electric motor, in this embodiment, higher torque can be obtained without affecting the high speed of the electric motor provided by each of the first drive circuit and the second drive circuit. In other words, both torque and high speed of the electric motor can be achieved. Furthermore, the two drive circuits, the first drive circuit that operates the first magnetic field generating unit and the second drive circuit that operates the second magnetic field generating unit, only need to have voltage application capabilities corresponding to the size of the coils provided in the magnetic field generating units operated by each drive circuit. Therefore, a drive circuit that is smaller and generates less heat than a drive circuit for operating an electric motor having the combined size of the first magnetic field generating unit and the second magnetic field generating unit can be employed. Therefore, the entire rotary drive system can be made smaller and lighter. That is, an electric motor that can obtain torque equivalent to that of an electric motor having the combined size of the first magnetic field generating unit and the second magnetic field generating unit can be controlled by a smaller and lighter control system. From the above, the rotary drive system (e.g., drive control system 1 or drive control system) of the present disclosure can ensure higher torque and high speed while suppressing size increase.

[0077] Generally, the torque T of an electric motor is a function of the magnitude of the current I flowing through the coil, the torque constant Kt (number of coil turns n × number of magnetic flux penetrating the iron core φ × number of pole pairs P), and the efficiency η, which depends on the magnitude of the current (T = I × Kt × η). The maximum rotational speed ωmax of an electric motor is a function of the maximum voltage V applied to the coil and the inverse of the torque constant (ωmax = V / Kt). Therefore, increasing both the maximum rotational speed and maximum torque of an electric motor cannot be achieved by simply changing the motor's basic design (torque constant or number of coil turns). Instead, this problem is solved by increasing at least one of the current I or voltage V supplied to the coil from the driver circuit that drives the electric motor. However, such driver circuits with higher electrical specifications naturally have many problems, such as being larger, heavier, generating more heat, being more expensive, and being less available (depending on the required performance, they may not even be available as current products). Furthermore, as voltage increases, the required safety features, such as protection against electric shock, also become more stringent, potentially resulting in increased weight to ensure safety. Furthermore, because batteries are typically used as power sources for mobile robots and other devices with unrestricted ranges of motion, the technical difficulty of ensuring high voltage tends to be greater than for devices that can use external power sources. Given these technical constraints, the only way to increase torque without reducing the motor's rotation speed is to increase the motor's efficiency η, which entails a significant increase in the motor's weight. This would defeat the very concept of a battery-powered robot. Even if this were possible, increasing the motor's weight to increase torque would result in a vicious cycle in which the robot's own weight would increase, thereby increasing the motor's load. In contrast, the rotary drive system of the embodiment, as described above, can achieve torque equivalent to that of a motor with the combined size of the first and second magnetic field generating units, while still ensuring high speed and minimizing size. In other words, by providing two coil systems with a reduced number of coil turns n for one motor and driving each with a separate drive circuit, it becomes possible to increase both the maximum torque and maximum rotation speed without changing the power supply voltage or the maximum current of the drive circuit.This disclosure has demonstrated that the configuration disclosed herein is extremely effective for new types of non-stationary, battery-powered robots, such as those worn by humans or supporting their weight, based on insights into the characteristics required for such robots. Assistive robots worn by humans or supporting their weight do not require both maximum rotational speed and maximum torque simultaneously. For example, they are used for tasks such as assisting humans with slow movements that require large amounts of force (e.g., assisting with lifting luggage or standing up), and for tasks such as approaching the human with quick movements in the air just before contact. Due to these needs and safety considerations (e.g., excessive power can cause unintended sudden movements), both large force and rapid movement are not required simultaneously. Furthermore, there is also a demand for avoiding both large force and rapid movement simultaneously, as this increases safety. Furthermore, the power source for such robots is often a battery, and size and weight constraints limit the output current (DC) from the battery. If the drive circuit attempts to draw a current greater than its current capacity, the supply voltage may become unstable, potentially causing the robot's operation to become unstable, and the performance requirements may not be met. (If this were to happen, the battery would heat up to an unacceptable high temperature, making the product unsuitable for sale.) On the other hand, by splitting the winding into two and using two drive circuits, it is possible to output greater power, and in this case, the drive circuits will attempt to draw a greater current from the battery. Naturally, the product fully satisfies both the current requirements and safety requirements. However, in consideration of the characteristics of such current requirements, a means for imposing limitations on the motor drive circuits may be introduced to further ensure safety. One example of such a means is to provide logic in each of the two drive circuits of the motor or in the robot's host controller that estimates the magnitude of the DC input current to the drive circuit from the drive circuit output current and the motor rotation speed.Another example of such a means is to create a map of the drive circuit output current and motor rotation speed in each of the two drive circuits of the motor or in the robot's upper controller, and to set an undesirable operating region in advance. Another example of such a means is to introduce logic in each of the two drive circuits of the motor or in the robot's upper controller that reduces the drive circuit output current when the estimated DC input current exceeds a predetermined threshold, or when the drive circuit output current and the motor rotation speed detected by the drive circuit fall into an undesirable region of the map. By using at least one of these means, a motor drive system that is safer and more compatible with batteries can be realized by using only the sensing functions normally provided in normal drive circuits, without providing any new sensors.

[0078] In addition, in the rotary drive system of the embodiment (e.g., drive control system 1 or drive control system), one of two coils arranged at opposing positions across the rotation axis (rotation axis C) of the rotor (e.g., rotor 31) is arranged in a first magnetic field generating unit (e.g., first system S1), and the other is arranged in a second magnetic field generating unit (e.g., second system S2).

[0079] Therefore, the concept of voltage control for suppressing cogging due to mutual interference between the magnetic field generated by the first magnetic field generating unit (e.g., first system S1) and the magnetic field generated by the second magnetic field generating unit (e.g., second system S2) can be simplified, making it easier to design a rotary drive system (e.g., drive control system 1 or drive control system).

[0080] In addition, in a rotational drive system (e.g., drive control system 1 or drive control system) of an embodiment, a first magnetic field generation unit (e.g., first system S1) has a U-phase magnetic field generation unit (e.g., U-phase magnetic field generation unit U1), a V-phase magnetic field generation unit (e.g., V-phase magnetic field generation unit V1), and a W-phase magnetic field generation unit (e.g., W-phase magnetic field generation unit W1). In addition, a second magnetic field generation unit (e.g., second system S2) has a U-phase magnetic field generation unit (e.g., U-phase magnetic field generation unit U2), a V-phase magnetic field generation unit (e.g., V-phase magnetic field generation unit V2), and a W-phase magnetic field generation unit (e.g., W-phase magnetic field generation unit W2). When the total number of coils provided in the first magnetic field generation unit and the second magnetic field generation unit is k and the number of magnetic poles of the rotor is q, the value obtained by dividing k by three times q is not an integer.

[0081] Therefore, it is possible to provide a rotary drive system (e.g., drive control system 1 or drive control system) equipped with a motor (e.g., motor 30 or motor 35) that exhibits superior effects to those of a fractional slot three-phase AC motor, such as reduced torque ripple.

[0082] In addition, in the rotary drive system of the embodiment (e.g., drive control system 1 or drive control system), the coils provided in the first magnetic field generating unit (e.g., first system S1) and the second magnetic field generating unit (e.g., second system S2) are formed by distributed winding.

[0083] Therefore, it is possible to provide a rotary drive system (e.g., drive control system 1 or drive control system) equipped with a motor (e.g., motor 30 or motor 35) that can obtain higher torque compared to a motor of the same size constructed with a coil using concentrated winding.

[0084] The electric motor of the embodiment is an electric motor that is provided in a configuration in which the weight of the device is included in the weight of the device and the weight of the device acts as a load for the operation of the electric motor, or in a configuration in which a person supports part or all of the weight of the electric motor and the weight of the electric motor acts as a load for the operation of the electric motor, and is provided with a first magnetic field generating unit that includes a plurality of coils and generates a magnetic field for rotating a rotor, and a second magnetic field generating unit that is provided separately from the first magnetic field generating unit and includes a plurality of coils and generates a magnetic field for rotating the rotor, One of two coils is provided in the first magnetic field generating unit, and the other is provided in the second magnetic field generating unit, and the first magnetic field generating unit and the second magnetic field generating unit have a U-phase magnetic field generating unit, a V-phase magnetic field generating unit, and a W-phase magnetic field generating unit. If the total number of coils provided in the first magnetic field generating unit and the second magnetic field generating unit is k and the number of magnetic poles of the rotor is q, then the value obtained by dividing k by three times q is not an integer, and the coils provided in the first magnetic field generating unit and the second magnetic field generating unit are formed by distributed winding.

[0085] Therefore, by operating both the first magnetic field generator (e.g., first system S1) and the second magnetic field generator (e.g., second system S2) while aligning the rotor rotation drive direction, higher torque can be obtained compared to operating only one of the first magnetic field generator and the second magnetic field generator. Furthermore, while attempts to increase the torque performance of a motor generally tend to impair the motor's high speed (maximum rotation speed), this embodiment achieves higher torque without affecting the high speed of the motor achieved by the first drive circuit and the second drive circuit. In other words, both torque and high speed of the motor can be achieved. Furthermore, the concept of voltage control for suppressing cogging due to mutual interference between the magnetic fields generated by the first magnetic field generator and the second magnetic field generator can be simplified, making it easier to design the motor and its control system. Furthermore, the advantages of a fractional slot three-phase AC motor, such as reduced torque ripple, can be achieved. Furthermore, higher torque can be obtained compared to a motor of the same size constructed with concentrated winding coils. Furthermore, the two drive circuits, the first drive circuit that operates the first magnetic field generator and the second drive circuit that operates the second magnetic field generator, only need to have voltage application capabilities appropriate for the size of the coils provided in the magnetic field generators operated by each drive circuit. Therefore, drive circuits that are smaller and generate less heat than drive circuits for operating a motor of the combined size of the first magnetic field generator and the second magnetic field generator can be employed. In other words, the electric motor of the present disclosure (e.g., electric motor 30 or electric motor 35) facilitates the miniaturization and weight reduction of the control system. Therefore, configurations equipped with the electric motor of the present disclosure facilitate miniaturization and weight reduction. From the above, the electric motor of the present disclosure can ensure higher torque and high speed while suppressing size increase. [Explanation of symbols]

[0086] 1 Rotational Drive System 10 Control device 13 First control device 14 Second control device 21, 23 First drive circuit 22, 24 Second drive circuit 30,35,300 Electric motor 100 walking robots 200 Assist Device U1, U2 U-phase magnetic field generator V1,V2 V-phase magnetic field generation section W1, W2 W-phase magnetic field generating section U1A, U1B, U1C, V1A, V1B, V1C, W1A, W1B, W1C, U2A, U2B, U2C, V2A, V2B, V2C, W2A, W2B, W2C coil

Claims

1. An electric motor, a control unit that controls the operation of the electric motor, The electric motor is provided in a configuration in which the weight of the electric motor is included in the weight of the device, and the weight of the device acts as a load when the electric motor is operated, or in which a person supports part or all of the weight of the electric motor, and the weight of the electric motor acts as a load when the electric motor is operated, a first magnetic field generating unit including a plurality of coils and configured to generate a magnetic field for rotating the rotor; a second magnetic field generating unit provided separately from the first magnetic field generating unit, including a plurality of coils, and generating a magnetic field for rotating the rotor; a position sensor that outputs a signal indicating a rotation angle of the rotor, The control unit a first drive circuit that operates the first magnetic field generation unit; a second drive circuit that operates the second magnetic field generation unit, the first drive circuit and the second drive circuit are both operable in a state in which a direction in which the rotor is rotationally driven by the first magnetic field generation unit and a direction in which the rotor is rotationally driven by the second magnetic field generation unit are the same; a first mode in which either the first magnetic field generating unit or the second magnetic field generating unit is operated and the other is not operated, and a second mode in which both the first drive circuit and the second drive circuit are operated in a state in which the direction of rotation of the rotor by the first magnetic field generating unit and the direction of rotation of the rotor by the second magnetic field generating unit are made the same; when it is determined that an abnormality has occurred in which the other of the two motors does not operate or is not synchronized with the other of the two motors based on a relationship between the drive control by the first drive circuit, the drive control by the second drive circuit, and the output of the position sensor, the control unit operates the one of the two motors in the first mode. Rotary drive system.

2. One of two coils provided at positions facing each other across the rotation axis of the rotor is provided to the first magnetic field generating unit, and the other is provided to the second magnetic field generating unit. The rotary drive system of claim 1 .

3. The first magnetic field generation unit and the second magnetic field generation unit are a U-phase magnetic field generating unit; a V-phase magnetic field generating unit; a W-phase magnetic field generating unit; When the total number of coils provided in the first magnetic field generating unit and the second magnetic field generating unit is k and the number of magnetic poles of the rotor is q, the value obtained by dividing k by three times q is not an integer.

3. A rotary drive system according to claim 1 or 2.

4. The coils provided in the first magnetic field generating unit and the second magnetic field generating unit are formed by distributed winding. A rotary drive system according to any one of claims 1 to 3.

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