Smart knee joint for a human lower limb exoskeleton, a prosthesis and an orthosis
The present application relates to a smart knee joint for a human lower limb exoskeleton, a prosthesis, and an orthosis. The smart knee joint reproduces part or all of the biomechanics of the knee joint of the human body by using a motor driving unit and a controllable elastic energy storage unit based on a magnetorheological damper. The motor driving unit here can be replaced with a controllable damping unit. The smart knee joint is developed for helping amputees or patients with impaired mobility regain/repair natural gaits and also reduce their burden of walking. The motor drive unit operates in a generator mode and an actuator mode. Energy harvesting technologies are exploited to reduce the power consumption of the smart knee joint then to prolong the working time. In addition, the controllable elastic energy storage unit based on the magnetorheological damper can further reduce the energy consumption of the smart knee joint, and also simplify the control of the knee joint.
1. A smart knee joint for a human lower limb exoskeleton, a prosthesis, and an orthosis, attached to a knee joint, comprising:
1) a motor driving unit or a controllable damping unit, the motor driving unit including a motor and a transmission, and having two working modes: a generator mode and an actuator mode, the motor driving unit being adjusted to a corresponding working mode based on states and walking modes of the knee joint;
2) an elastic energy storage unit including an elastic element, a transmission, and a working mode regulator, the elastic energy storage unit having three working modes: being locked mode, free mode, and energy dissipation mode, the elastic energy storage unit being adjusted to a corresponding working mode based on states and walking modes of the knee joint, wherein the working mode regulator comprises a magnetorheological damper and a restoring spring;
3) sensors for detecting the motion of the knee joint;
4) a controller for monitoring the states and the walking modes of the knee joint in real-time based on signals of the sensors, and generating control signals for the elastic energy storage unit and the motor driving unit or the controllable damping unit;
5) a power supply for powering the motor driving unit, the controllable damping unit, the elastic energy storage unit, the sensors, and the controller, and storing electric energy recovered by the motor, the power supply being one or both of a battery and a supercapacitor; and
6) connecting devices comprising a thigh connecting device and a shank connecting device.
2. The smart knee joint of claim 1 , wherein the motor driving unit comprises a motor, a gear reduction box, and a bevel gear transmission.
3. A smart knee joint of claim 1 , wherein the motor driving unit comprises a motor and a harmonic gear transmission.
4. The smart knee joint of claim 1 , wherein the motor driving unit comprises a motor, a gear transmission, a ball-screw transmission, and a slider-crank mechanism.
5. The smart knee joint of claim 1 , wherein the motor driving unit comprises a motor, a timing-belt transmission, a ball-screw transmission, and a slider-crank mechanism.
6. The smart knee joint of claim 1 , wherein the elastic energy storage unit is configured in parallel with the motor driving unit.
7. The smart knee joint of claim 1 , wherein the elastic element, the transmission, and the working mode regulator are arranged in series.
8. The smart knee joint of claim 1 , wherein the elastic element in the elastic energy storage unit is one or more of a coil spring, a leaf spring, a gas spring, and a rubber spring.
9. The smart knee joint of claim 1 , wherein the transmission in the elastic energy storage unit is one or more of a pulley rope mechanism, a slider-crank mechanism, and a cam mechanism.
10. The smart knee joint of claim 9 , wherein a cam profile of the cam is arranged to satisfy a specific elastic torque-angle curve.
11. The smart knee joint of claim 1 , wherein when the elastic energy storage unit operates in the being locked mode, the magnetorheological damper in the working mode regulator is energized to be locked.
12. The smart knee joint of claim 1 , wherein the magnetorheological damper in the working mode regulator is de-energized when the elastic energy storage unit is operating in the free mode.
13. The smart knee joint of claim 1 , wherein when the elastic energy storage unit operates in the energy dissipation mode, the magnetorheological damper in the working mode regulator is energized, but there is a relative motion between a damper piston and a damper housing, a damping force is regulated by adjusting the current applied to the magnetorheological damper.
14. The smart knee joint of claim 1 , wherein the sensors comprise one or more of an axial force sensor, a torque sensor, a knee angle sensor, an inertial measurement unit for measuring the motion of the thigh, an inertial measurement unit for measuring the motion of the shank, and electromyographic signal sensors.
15. The smart knee joint of claim 1 , wherein the controller detects the motion states and the walking modes of the knee joint based on the signals of the sensors, and generates one or both of a reference angle or a reference torque for the motor driving unit.
16. The smart knee joint of claim 1 , wherein the knee joint is enabled to fully or partially reproduce the biomechanics of the human knee joint by controlling the motor driving unit, the controllable damping unit, and the elastic energy storage unit.
17. The smart knee joint of claim 16 , wherein the biomechanics of the human knee joint is a torque-angle curve during the stance phase and an angle curve during the swing phase.
18. The smart knee joint of claim 1 , wherein the controllable damping unit is a magnetorheological rotary brake capable of adjusting an impedance torque of the controllable damping unit by controlling the current applied to the magnetorheological rotary brake.
19. The smart knee joint of claim 1 , wherein the controllable damping unit comprises a magnetorheological damper and a slider-crank mechanism, and the magnetorheological damper is capable of adjusting an impedance torque of the controllable damping unit by controlling the current applied to the magnetorheological damper.
20. The smart knee joint of claim 1 , wherein the controllable damping unit comprises a hydraulic cylinder, a hydraulic valve, and a slider-crank mechanism, and an impedance torque of the controllable damping unit is controlled by adjusting the hydraulic valve.
21. The smart knee joint of claim 1 , wherein the controllable damping unit is connected in parallel with the elastic energy storage unit.
22. A method of control of a knee joint, comprising:
detecting motion of the knee joint by sensors included in a smart knee joint for a human lower limb exoskeleton, a prosthesis, and an orthosis, the smart knee joint being attached to the knee joint and comprising an elastic energy storage unit, and a motor drive unit or a controllable damping unit; and
providing control signals for the elastic energy storage unit and the motor drive unit or the controllable damping unit based on the signals of the sensors, wherein the motor drive unit includes a motor and a transmission, and has two working modes: a generator mode and an actuator mode, the motor drive unit being adjusted to a corresponding working mode based on states and walking modes of the knee joint,
wherein the elastic energy storage unit includes an elastic element, a transmission, and a working mode regulator, the elastic energy storage unit having three working modes: being locked mode, free mode, and energy dissipation mode, and the elastic energy storage unit being adjusted to a corresponding working mode based on the states and the walking modes of the knee joint, wherein the working mode regulator comprises a magnetorheological damper and a restoring spring;
wherein the control signals are generated by a controller included in the smart knee joint, and the controller is configured for monitoring the states and the walking modes of the knee joint in real-time based on the signals of the sensors, and generating the control signals for the elastic energy storage unit, and the motor drive unit or the controllable damping unit;
wherein the smart knee joint further comprises: a power supply for powering the motor drive unit, the controllable damping unit, the elastic energy storage unit, the sensors, and the controller, and storing electric energy recovered by the motor, the power supply being one or both of a battery and a supercapacitor; and connecting devices comprising a thigh connecting device and a shank connecting device.
23. An apparatus for assisting walking, comprising a smart knee joint,
wherein the smart knee joint comprises:
1) a motor driving unit or a controllable damping unit, the motor driving unit including a motor and a transmission, and having two working modes: a generator mode and an actuator mode, the motor driving unit being adjusted to a corresponding working mode based on states and walking modes of the knee joint;
2) an elastic energy storage unit including an elastic element, a transmission, and a working mode regulator, the elastic energy storage unit having three working modes: being locked mode, free mode, and energy dissipation mode, the elastic energy storage unit being adjusted to a corresponding working mode based on states and walking modes of the knee joint, wherein the working mode regulator comprises a magnetorheological damper and a restoring spring;
3) sensors for detecting the motion of the knee joint;
4) a controller for monitoring the states and the walking modes of the knee joint in real-time based on signals of the sensors, and generating control signals for the elastic energy storage unit and the motor driving unit or the controllable damping unit;
5) a power supply for powering the motor driving unit, the controllable damping unit, the elastic energy storage unit, the sensors, and the controller, and storing electric energy recovered by the motor, the power supply being one or both of a battery and a supercapacitor; and
6) connecting devices comprising a thigh connecting device and a shank connecting device.