JP2017046779A - Walking assisting device and walking assisting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a walking assisting device that can be manufactured at low cost while keeping its performance.SOLUTION: A walking assisting device includes a first frame mounted on one leg, a second frame connected rotatably to the first frame at a hip joint position, and mounted on the other leg, a detection unit for detecting a relative angular speed between the first frame and the second frame, a first electric motor fixed to the first frame, a control unit for controlling an operation of the first electric motor on the basis of the result of the detection by the detection unit, a planetary gear mechanism for rotatably connecting the first frame and the second frame, and a second electric motor fixed to the first frame. The planetary gear mechanism includes a first gear rotationally driven by the first electric motor, at least one second gear rotatably provided to the second frame and engaged with the first gear, and a third gear engaged with the second gear. The second electric motor applies a load to the third gear.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to a walking assistance device and a walking assistance method that assist a person's walking motion.

  In general, the walking assistance device includes actuators at a total of four locations outside the hip joint and outside the knee joint. An actuator that incorporates a plurality of planetary gears to increase the torque by increasing the reduction ratio is also known.

  Actuator drive control is performed, for example, when the control unit detects a human movement using a myoelectric potential sensor or a torque sensor and supplies the actuator with a current having a direction and magnitude corresponding to the movement. The

JP 2004-89373 A

  However, the conventional walking assist device described above requires a relatively expensive myoelectric potential sensor and torque sensor and requires four actuators, so that the manufacturing cost can be kept low while maintaining the performance of the device. That was difficult.

  Therefore, development of a walking assist device that can be manufactured at low cost while maintaining performance is desired.

  The walking assist device according to the embodiment includes a first frame that is attached to one leg, a second frame that is rotatably connected to the first frame at the position of the hip joint, and is attached to the other leg. A detection unit for detecting a relative angular velocity between the first frame and the second frame, a first motor fixed to the first frame, and a control unit for controlling the operation of the first motor based on a detection result in the detection unit; And a planetary gear mechanism that rotatably connects the first frame and the second frame, and a second electric motor fixed to the first frame. The planetary gear mechanism includes a first gear that is rotationally driven by the first electric motor, at least one second gear that is rotatably provided on the second frame and meshed with the first gear, and meshed with the second gear. Having a third gear. The second electric motor applies a load to the third gear.

  In addition, according to the walking assistance method according to the embodiment, in the above-described walking assistance device, the second motor is controlled so as to apply a load to the third gear, and the movement of the first gear follows the movement of both legs. The first electric motor is controlled based on the detection result in the detection unit.

FIG. 1 is an external view showing a state in which a walking assistance device according to the embodiment is mounted on a user. FIG. 2 is an exploded perspective view of the walking assist device of FIG. FIG. 3 is a schematic view showing the planetary gear mechanism of FIG. FIG. 4 is a block diagram showing a control system of the walking assist device of FIG. FIG. 5 is a block diagram showing a control system of a main motor included in the control unit of the walking assist device of FIG. FIG. 6 is a block diagram showing a control system of a sub motor included in the control unit of the walking assist device of FIG. FIG. 7 is a graph showing an example of a change in relative angular velocity measured by the walking assist device of FIG. FIG. 8 is an operation explanatory diagram for explaining the operation of the walking assist device of FIG. 1.

Hereinafter, embodiments will be described in detail with reference to the drawings.
FIG. 1 is an external view illustrating a state in which a walking assist device 100 according to the embodiment is mounted on a user P.

  The walking assist device 100 includes a right unit 10R to be attached to the right leg of the user P, a left unit 10L to be attached to the left leg of the user P, and a connecting frame 20 (connecting member) that connects the right unit 10R and the left unit 10L. Have The right unit 10R has a right cover 11R, and the left unit 10L has a left cover 11L.

  FIG. 2 is an exploded perspective view in which the walking assist device 100 is disassembled. In FIG. 2, illustration of the two left and right covers 11R and 11L is omitted. In FIG. 2, the control unit 110 (FIG. 4) and the battery 112 (FIG. 4) housed in the right cover 11R are not shown. The control unit 110 and the battery 112 are fixed to the outer surface of the right frame 12R, which will be described later, and are covered with the right cover 11R.

  The right unit 10R includes a substantially rectangular plate-shaped right frame 12R (second frame) disposed along the outer side of the thigh of the right leg of the user P. The right frame 12R is formed of, for example, a single metal plate integrally including an upper portion 12Ru disposed on the right side of the waist of the user P and a lower portion 12Rd disposed outside the right thigh. Yes.

  The right frame 12R is bent slightly inward at the boundary portion between the upper portion 12Ru and the lower portion 12Rd in accordance with the shape of the right leg. The right frame 12R is attached to the right leg by attaching the lower portion 12Rd to the right leg of the user P with two sets of upper and lower clamp arms 13Ru and 13Rd (FIG. 1).

  Similarly, the left unit 10L includes a substantially rectangular plate-shaped left frame 12L disposed along the outside of the thigh of the left leg of the user P. The left frame 12L is formed of, for example, a single metal plate integrally having an upper portion 12Lu disposed on the left side of the waist of the user P and a lower portion 12Ld disposed on the outer side of the left thigh. Yes.

  The left frame 12L is bent slightly inward at the boundary portion between the upper portion 12Lu and the lower portion 12Ld in accordance with the shape of the left leg. The left frame 12L is attached to the left leg by attaching the lower portion 12Ld to the left leg of the user P with two sets of upper and lower clamp arms 13Lu and 13Ld (FIG. 1).

  The right frame 12R and the left frame 12L may have any shape, size, material and the like as long as they have sufficient mechanical strength. In addition, as a mounting tool for mounting the right frame 12R and the left frame 12L on the respective legs, a stretchable belt or the like may be used. When the user P moves, the frames 12R and 12L can be easily used. Anything that doesn't come off.

  The connecting frame 20 is formed by bending a pipe having a cylindrical cross section, and has a hollow structure into which cables C1 to C5 (FIG. 4) described later can be inserted. The connecting frame 20 is curved in a direction away from the user P so as not to contact the user P while moving. In the present embodiment, the connecting frame 20 is arranged in front of the user P. However, the connecting frame 20 can be arranged behind the user P.

  The right end 20R of the connecting frame 20 is connected to a connector 12C provided on the upper portion 12Ru of the right frame 12R. The connector 12C of the right frame 12R mechanically fixes the right end 20R of the connection frame 20 and electrically connects a cable passing through the connection frame 20.

  The left end 20 </ b> L of the connection frame 20 is connected to a substantially disk-shaped carrier 15. The carrier 15 has a connector 15C that protrudes radially outward from its outer peripheral surface. The connector 15C of the carrier 15 also mechanically fixes the left end 20L of the connecting frame 20 and electrically connects a cable passing through the connecting frame 20. That is, the right frame 12R, the connecting frame 20, and the carrier 15 are integrally connected and function as a rigid body.

  FIG. 3 is a schematic view of the planetary gear mechanism 1. The carrier 15 is included in the planetary gear mechanism 1. In addition to this, the planetary gear mechanism 1 includes three planetary gears 21 (second gear), a ring gear 22 (first gear), and a sun gear 24 (third gear).

  As shown in FIG. 2, the carrier 15 is disposed outside the upper portion 12Lu of the left frame 12L. The carrier 15 has a rotating shaft 15a protruding from the inner surface facing the left frame 12L along the central axis. The upper portion 12Lu of the left frame 12L is provided with a shaft hole 12a that rotatably receives the rotation shaft 15a of the carrier 15. The carrier 15 is pivotally attached to the upper portion 12Lu of the left frame 12L by inserting the rotation shaft 15a through the shaft hole 12a of the left frame 12L.

  For this reason, the right frame 12R (first frame) integrally connected to the carrier 15 via the connecting frame 20 can rotate relative to the left frame 12L around the rotation shaft 15a of the carrier 15. It becomes. That is, the connecting frame 20 connecting the right frame 12R and the carrier 15 moves up and down in accordance with the movement of the right leg of the user P.

  Three receiving shafts 15b are integrally projected on the outer surface of the carrier 15, that is, the surface opposite to the inner surface on which the rotation shaft 15a is provided. The three receiving shafts 15b are arranged at equal intervals along the center of the carrier 15, that is, the circumference centered on the rotating shaft 15a. Each receiving shaft 15b holds the planetary gear 21 so as to be freely rotatable. In this embodiment, the carrier 15 is provided with the three receiving shafts 15b and the three planetary gears 21 are attached. However, the receiving shaft 15b and the planetary gear 21 may be at least one set.

  A ring gear 22 rotated by a main motor 31 (first electric motor) is provided outside the three planetary gears 21. The ring gear 22 has internal teeth 22 a that mesh with the three planetary gears 21 on the inner surface facing the three planetary gears 21. The ring gear 22 is connected to a motor gear 31 a provided on the rotating shaft of the main motor 31 via an endless toothed belt 23. The ring gear 22 has external teeth 22 b that mesh with the toothed belt 23. When the main motor 31 is rotated, the ring gear 22 is rotated and the three planetary gears 21 are rotated.

  Inside the three planetary gears 21, a sun gear 24 to which torque is applied by a sub motor 32 (second electric motor) is provided. The sun gear 24 meshes with the three planetary gears 21. For example, when the main motor 31 is rotated in a state where a large torque is applied to the sun gear 24 and stopped, the driving force generated by the main motor 31 is transmitted to the carrier 15 using the sun gear 24 as a fulcrum of force. Conversely, when the sun gear 24 is freely rotatable and the main motor 31 is rotated, the sun gear 24 idles and the driving force generated by the main motor 31 is hardly transmitted to the carrier 15.

  The stator (stator) of the main motor 31 and the sub motor 32 is fixed to the left frame 12L. A description of the fixing structure of the motors 31 and 32 is omitted. Therefore, the stators (stators) of the two motors 31 and 32 move integrally with the left frame 12L.

  The carrier 15, the three planetary gears 21, the ring gear 22, the timing belt 23, the sun gear 24, the main motor 31, and the sub motor 32 are accommodated in the left cover 11L. In other words, each component of the left unit 10L is designed not to have a size and layout as shown in FIGS. 2 and 3, but to have a size and layout that can be accommodated in the left cover 11L.

FIG. 4 is a block diagram of a control system that controls the operation of the walking assist device 100. The control system of the walking assist device 100 includes a control unit 110.
As shown in FIGS. 2 and 4, the two motors 31 and 32 include encoders 33 and 34 for detecting the rotational angular velocities thereof. Further, an encoder 36 (detection unit) for detecting a relative angular velocity between the right frame 12R and the left frame 12L is provided at a connection portion between the left frame 12L and the carrier 15. The encoders 33 and 34 of the two motors 31 and 32 and the encoder 36 of the connecting portion may be replaced with another sensor such as a resolver.

  In order to reduce the mass of the walking assist device 100 and increase the assist force, it is desirable that the main motor 31 and the sub motor 32 include a speed reducer. Further, the output ratio of the main motor 31 and the sub motor 32 is selected so as to be equal to the reduction ratio of the planetary gears (three planetary gears 21, the ring gear 22, and the sun gear 24) described above. For example, when the reduction ratio of the planetary gears 21, 22, and 24 is 6: 1, the main motor 31 with an output of 60 W and the sub motor 32 with an output of 10 W may be combined.

  The main motor 31 and the sub motor 32 are connected to the battery 112 via power supply cables C1 and C2, respectively. The three encoders 33, 34, and 36 are connected to the control unit 110 via signal cables C3, C4, and C5, respectively. The control unit 110 and the battery 112 are arranged in the right unit 10R, and the two motors 31, 32 and the three encoders 33, 34, 36 are arranged in the left unit 10L. Therefore, the power supply cables C1 and C2 that connect the motors 31 and 32 and the battery 112, and the signal cables C3, C4, and C5 that connect the encoders 33, 34, and 36 to the control unit 110 are inserted into the connection frame 20. .

Hereinafter, the configuration and operation of the control unit 110 provided in the right unit 10R will be described with reference to FIGS.
FIG. 5 is a block diagram showing a control system of the main motor (first electric motor) 31. The control system of the main motor 31 includes an amplifier 41, an adder / subtractor 42, a speed controller 43, an adder / subtractor 44, a current controller 45, and a current detector (not shown). In this control system, both the speed controller 43 and the current controller 45 use proportional-integral control (PI control, phase delay compensation).

  When the walking assist operation is started, first, in this control system, a constant angular velocity ωc (angular velocity generated by the movement of the user P) between the carrier 15 and the left frame 12L calculated from the output of the encoder 36 is constant by the amplifier 41. Multiply by α to calculate the target angular velocity. FIG. 7 shows an example of a change in the relative angular velocity ωc actually measured.

  Next, the calculated target angular velocity and the actual rotational angular velocity ωm of the main motor 31 calculated from the output of the encoder 33 are input to the adder / subtractor 42, and the difference between the target angular velocity and the actual rotational angular velocity ωm is calculated. Then, the difference between the calculated angular velocities is input to the speed controller 43, and the speed controller 43 generates a target current.

  On the other hand, in this control system, the current actually flowing to the main motor 31 is measured by a current detector (not shown) and input to the adder / subtractor 44. The adder / subtractor 44 calculates the difference between the input actual current and the target current generated by the speed controller 43 described above, and inputs the calculation result to the current controller 45. The current controller 45 determines a voltage to be applied to the main motor 31 based on the input current difference.

  FIG. 6 is a block diagram showing a control system of the sub motor 32 (second electric motor). The control system of the sub motor 32 includes an impedance controller 51, an adder / subtractor 52, a current controller 53, and a current detector (not shown). In this control system, the current controller 53 uses proportional-integral control (phase delay compensation). However, in the impedance controller 51, a current value (target current) for controlling the inertial force proportional to the angular acceleration of the rotor obtained by second-order differentiation of the rotation angle from the angular velocity obtained by first-order differentiation of the rotation angle of the sub motor 32. Is used to calculate differential control (phase lead compensation).

  Even if a voltage is simply applied to the main motor 31 by the control system described above, an assist force cannot be generated. That is, the driving force by the main motor 31 escapes to the sun gear 24. For this reason, in order to transmit the driving force of the main motor 31 to the carrier 15 as an assist force, it is necessary to energize the sub motor 32 and apply load torque to the sun gear 24. For this reason, the control system of the sub motor 32 executes impedance control for virtually increasing the rotor inertia of the sub motor 32 simultaneously with the start of the walking assist operation.

  In the control system of the sub motor 32, first, the rotor angular velocity ωs of the sub motor 32 calculated based on the output of the encoder 34 is input to the impedance controller 51. The impedance controller 51 generates a target current that increases the rotor inertia of the sub motor 32 and outputs the target current to the adder / subtractor 52.

  On the other hand, in this control system, the current flowing through the sub motor 32 is detected by a current detector (not shown) and output to the adder / subtractor 52. Then, the adder / subtracter 52 calculates the difference between the input actual current and the target current generated by the impedance controller 51 described above, and inputs the calculation result to the current controller 53. The current controller 53 determines a voltage to be applied to the sub motor 32 based on the input current difference.

  As described above, when the impedance control is performed on the sub motor 32, the driving force of the main motor 31 can be transmitted to the carrier 15 simultaneously with the start of the walking motion, and the assist force can be generated. At this time, the magnitude of the assist force is generally determined according to the magnification α of the angular velocity amplified by the amplifier 41 included in the control system of the main motor 31, but is set by the impedance controller 51 included in the control system of the sub motor 32. The amount of the rotor inertia increases, that is, the load torque applied to the sun gear 24 by the sub motor 32 varies. In other words, the assist force can be set to an arbitrary value by changing the magnification α of the angular velocity to be amplified on the main motor 31 side and the increase amount of the rotor inertia set on the sub motor 32 side.

Next, the walking motion of the user P wearing the walking assist device 100 of this embodiment will be described with reference to FIG.
As shown on the right side of FIG. 8, when the user P wearing the walking assist device 100 moves the left leg forward with the right leg as an axis foot, the right frame 12 </ b> R is substantially stopped with respect to the ground, The frame 12L rotates in the clockwise direction in the drawing. At this time, the main motor 31 has a direction in which the angle between the connecting frame 20 and the left frame 12L is narrowed so that the movement of the walking assist device 100 follows the movement (relative angular velocity) of the left leg of the user P (illustrated). The carrier 15 is rotated counterclockwise.

  Further, as shown on the left side of FIG. 6, when the user P puts the right leg forward with the left leg as an axis foot, the right frame 12R is shown in the state where the left frame 12L substantially stops with respect to the ground. Rotate around. At this time, the main motor 31 expands the angle between the connecting frame 20 and the left frame 12L so that the movement of the walking assist device 100 follows the movement (relative angular velocity) of the right leg of the user P (illustrated). The carrier 15 is rotated in the clockwise direction.

  That is, the walking assistance device 100 drives and controls the main motor 31 so as to follow the walking motion of the user P, and rotates the carrier 15 alternately in both directions. As a result, the walking assist device 100 assists the walking motion of the user P.

  As described above, according to the walking assist device 100 of the present embodiment, the frame 12R (12L) on the axis foot side when the user P walks is substantially fixed to the ground, and the frame 12L (12R) on the opposite side is fixed. Therefore, it is not necessary to provide a drive mechanism on both legs, the apparatus configuration can be simplified, the manufacturing cost of the apparatus can be reduced, and the apparatus can be reduced in weight. Further, according to the walking assist device 100 of the present embodiment, it is not necessary to use a relatively expensive myoelectric potential sensor or torque sensor, and the operation control can be simplified, so that the manufacturing cost of the device can be reduced accordingly.

  In addition, according to the present embodiment, the load torque is applied to the sun gear 24 by the sub motor 32 and the driving force of the main motor 31 is transmitted to the carrier 15. For example, the user P wearing the walking assist device 100 is used. Even if a sudden force that is unintentionally applied to the walking assist device 100 acts on the walking assist device 100, it absorbs all such undesired stress without transmitting it to the user P (as assisting force). Can do. For this reason, according to the present embodiment, the walking motion can be safely assisted without hindering the walking by the user P. Moreover, the user P can walk without a sense of incongruity and can improve the convenience.

  Further, according to the present embodiment, when the user P wearing the walking assist device 100 walks, the connecting frame 20 moves up and down in accordance with the movement, but the connecting frame 20 does not interfere with the user P. Thus, the walking motion is not hindered.

  According to the walking assistance device 100 of the embodiment described above, the planetary gear mechanism 1 is used to connect the two frames 12R and 12L attached to the left and right legs so as to be rotatable, and drive generated by the main motor 31. Since the force is transmitted to the carrier 15 using the load torque of the sub motor 32, an expensive sensor is not required, and the apparatus configuration can be configured at low cost and light weight.

  The above-described embodiments are presented as examples and are not intended to limit the scope of the invention. The above-described embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. The above-described embodiments and modifications thereof are included in the invention described in the claims and equivalents thereof as well as included in the scope and spirit of the invention.

  For example, in the above-described embodiment, the case where the drive mechanism is attached to the left frame 12L and the right frame 12R and the carrier 15 are integrated by the connecting frame 20 is described. good.

  Moreover, although embodiment mentioned above demonstrated the case where the planetary gear mechanism 1 was used as a drive transmission mechanism of the walking assistance apparatus 100, not only this but another drive transmission mechanism may be used. For example, instead of the sun gear 24 that transmits the torque of the sub motor 32 to the planetary gear 21, a friction member that suppresses (or substantially prevents) the rotation of the planetary gear 21 may be used.

  DESCRIPTION OF SYMBOLS 1 ... Planetary gear mechanism, 10L ... Left unit, 10R ... Right unit, 11L ... Left cover, 11R ... Right cover, 12L ... Left frame, 12R ... Right frame, 15 ... Carrier, 20 ... Connection frame, 21 ... Planetary gear, 22 ... Ring gear, 24 ... Sun gear, 31 ... Main motor, 32 ... Sub motor, 33, 34, 36 ... Encoder, 100 ... Walking assist device, 110 ... Control unit, 112 ... Battery, C1-C5 ... Cables, P …User.

Claims (7)

A first frame attached to one leg;
A second frame rotatably connected to the first frame at the position of the hip joint and attached to the other leg;
A detector that detects a relative angular velocity between the first frame and the second frame;
A first electric motor fixed to the first frame;
A control unit for controlling the operation of the first electric motor based on a detection result in the detection unit;
A first gear that is rotationally driven by the first electric motor; at least one second gear that is rotatably provided on the second frame and meshed with the first gear; and a third gear meshed with the second gear. A planetary gear mechanism having a gear;
A second electric motor fixed to the first frame and applying a load to the third gear;
A walking assist device. The first electric motor rotationally drives the first gear at an angular velocity obtained by amplifying the relative angular velocity detected by the detection unit by a predetermined magnification;
The walking assist device according to claim 1. The detection unit includes an encoder provided at a connection portion between the first frame and the second frame.
The walking assist device according to claim 1 or 2. The second frame integrally includes a connecting member that is disposed in front of or behind the person wearing the device and moves in accordance with the movement of the other leg, and is provided at an end of the connecting member on the first frame side. A carrier is provided for rotatably mounting the at least one second gear of the planetary gear mechanism;
The walking assist device according to any one of claims 1 to 3. A battery that is fixed to the second frame and that feeds power to the first motor and the second motor;
The walking assist device according to any one of claims 1 to 4. A first frame attached to one leg;
A second frame rotatably connected to the first frame at the position of the hip joint and attached to the other leg;
A detector that detects a relative angular velocity between the first frame and the second frame;
A first electric motor fixed to the first frame;
A first gear that is rotationally driven by the first electric motor; at least one second gear that is rotatably provided on the second frame and meshed with the first gear; and a third gear meshed with the second gear. A planetary gear mechanism having a gear;
A second electric motor fixed to the first frame and applying a load to the third gear;
In a walking assist device having
The second electric motor is controlled so as to apply a load to the third gear, and the first motor is controlled based on the detection result of the detection unit so that the movement of the first gear follows the movement of both legs. Control the operation of the motor,
Walking assistance method. In a state where the first gear is moving in accordance with the movements of both the legs, the second gear is applied so that at least the third gear is moved in synchronization with the first gear. Control the operation of the motor,
The walking assist method according to claim 6.