A variable stiffness suspension system is provided for a wheelchair. The wheelchair has a frame and at least one wheel coupled to the frame for generally vertical movement relative to the frame. At least one sensor is provided for sensing an operating condition of the wheelchair. A controller is ope
A variable stiffness suspension system is provided for a wheelchair. The wheelchair has a frame and at least one wheel coupled to the frame for generally vertical movement relative to the frame. At least one sensor is provided for sensing an operating condition of the wheelchair. A controller is operatively coupled to the sensor. A controllable damper having a variable stiffness is coupled to the controller, the wheel and to the frame. The controllable damper is responsive to the controller and provides a force capable of being varied in a continuous manner. The force is resistive to movement of the wheel. The controllable damper is preferably a commercially available magneto-rheological damper or a variable orifice fluid damper. The controllable damper may be either a linear damper or a rotary brake.
대표청구항▼
What is claimed is: 1. A variable suspension system for use with a wheelchair having a forward end and a rear end, a frame, and at least one wheel coupled to at least one end of the frame for movement relative to the frame, the wheelchair further having a drive assembly operably coupled to the whee
What is claimed is: 1. A variable suspension system for use with a wheelchair having a forward end and a rear end, a frame, and at least one wheel coupled to at least one end of the frame for movement relative to the frame, the wheelchair further having a drive assembly operably coupled to the wheel to move the wheel toward or away from a supporting surface upon which the wheelchair is supported in response to moments generated by the drive assembly, the suspension system comprising: at least one sensor for sensing the vertical position of the wheel relative to the frame and generating a control input signal indicative of the wheel position; a controller operatively coupled to the sensor and responsive to the control input signal for generating a control output signal; and a controllable damper having a variable stiffness, operably coupled to the controller, the wheel, and the frame to provide a variable resistive force capable of being varied to any of multiple levels of force within a continuous range between upper and lower limits in response to the control output signal and resistive to the movement of the wheel, the resistive force being varied based at least in part upon the vertical position of the wheel. 2. The suspension system of claim 1 wherein the wheel is a rear wheel pivotally mounted to the rear end of the wheelchair. 3. The suspension system according to claim 1 wherein the controllable damper is a magneto-rheological fluid damper. 4. The suspension system according to claim 1 wherein the controllable damper is a fluid damper having an orifice with a size capable of being varied in response to the control output signal. 5. The suspension system according to claim 1 wherein the controllable damper is a linear damper. 6. The suspension system according to claim 1 further comprising a biasing member coupled to the wheel and biasing the wheel in a normal operative position wherein the wheel is positioned above a supporting surface in the predetermined position. 7. The suspension system according to claim 1, the wheelchair having a second wheel coupled to the frame for generally vertical movement relative to the frame, the suspension system comprising a second controllable damper operably coupled to the controller, the second wheel and the frame and providing a variable resistive force capable of being varied in response to the control output signal and resistive to the generally vertical movement of the second wheel. 8. The suspension system according to claim 1, the wheelchair having a second wheel coupled to the frame for generally vertical movement relative to the frame, the suspension system comprising a second controllable damper operably coupled to the controller, the second wheel and the frame and providing a variable resistive force capable of being independently varied in response to a second control output signal and resistive to the generally vertical movement of the second wheel. 9. A variable suspension system for use with a wheelchair having a forward end and a rear end, a frame, and at least one wheel coupled to at least one end of the frame for movement relative to the frame, the wheelchair further having a drive assembly operably coupled to the wheel to move the wheel toward or away from a supporting surface upon which the wheelchair is supported in response to moments generated by the drive assembly, the suspension system comprising: at least one sensor for sensing an operating condition of the wheelchair and generating a control input signal indicative of the operating condition; a controller operatively coupled to the sensor and responsive to the control input signal for generating a control output signal; and a controllable rotary brake having a variable stiffness, operably coupled to the controller, the wheel, and the frame to provide a variable resistive force capable of being varied to any of multiple levels of force within a continuous range between upper and lower limits in response to the control output signal and resistive to the movement of the wheel. 10. The suspension system of claim 9 wherein the wheel is a rear wheel pivotally mounted to the rear end of the wheelchair. 11. The suspension system of claim 9 wherein the controllable rotary brake resists upward motion of the wheel. 12. The suspension system according to claim 9 wherein the sensor is one of a tilt sensor, a microswitch or a gyroscopic sensor. 13. The suspension system according to claim 9, the drive assembly of the wheelchair comprising a motor, wherein the sensor is a torque sensor adapted to sense torque generated by the motor. 14. The suspension system according to claim 9 further comprising a biasing member coupled to the wheel and biasing the wheel in a predetermined position wherein the wheel is positioned above a supporting surface in the predetermined position. 15. The suspension system according to claim 9, the wheelchair having a second wheel coupled to the frame for generally vertical movement relative to the frame, the suspension system comprising a second controllable rotary brake operably coupled to the controller, the second wheel and the frame and providing a variable resistive force capable of being varied in response to the control output signal and resistive to the generally vertical movement of the second wheel. 16. The suspension system according to claim 9, the wheelchair having a second wheel coupled to the frame for generally vertical movement relative to the frame, the suspension system comprising a second controllable rotary brake operably coupled to the controller, the second wheel and the frame and providing a variable resistive force capable of being independently varied in response to a second control output signal and resistive to the generally vertical movement of the second wheel. 17. A variable suspension system for use with a wheelchair having a forward end and a rear end, a frame, and at least one wheel coupled to at least one end of the frame for movement relative to the frame, the wheelchair further having a drive assembly operably coupled to the wheel to move the wheel toward or away from a supporting surface upon which the wheelchair is supported in response to moments generated by the drive assembly, the suspension system comprising: at least one linearly variable displacement transducer sensor for sensing an operating condition of the wheelchair and generating a control input signal indicative of the operating condition; a controller operatively coupled to the sensor and responsive to the control input signal for generating a control output signal; and a controllable damper having a variable stiffness, operably coupled to the controller, the wheel, and the frame to provide a variable resistive force capable of being varied to any of multiple levels of force within a continuous range between upper and lower limits in response to the control output signal and resistive to the movement of the wheel. 18. The suspension system of claim 17 wherein the wheel is a rear wheel pivotally mounted to the rear end of the wheelchair. 19. The suspension system according to claim 17 wherein the controllable damper is a magneto-rheological fluid damper. 20. The suspension system according to claim 17 wherein the controllable damper is a fluid damper having an orifice with a size capable of being varied in response to the control output signal. 21. The suspension system according to claim 17 wherein the controllable damper is a linear damper. 22. The suspension system according to claim 17 further comprising a biasing wheel and biasing the wheel in a predetermined position wherein the wheel is positioned above a supporting surface in the predetermined position. 23. The suspension system according to claim 17 the wheelchair having a second wheel coupled to the frame for generally vertical movement relative to the frame, the suspension system comprising a second controllable damper operably coupled to the controller, the second wheel and the frame and providing a variable resistive force capable of being varied in response to the control output signal and resistive to the generally vertical movement of the second wheel. 24. The suspension system according to claim 17 the wheelchair having a second wheel coupled to the frame for generally vertical movement relative to the frame, the suspension system comprising a second controllable damper operably coupled to the controller, the second wheel and the frame and providing a variable resistive force capable of being independently varied in response to a second control output signal and resistive to the generally vertical movement of the second wheel.
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이 특허에 인용된 특허 (11)
Mulhern, James P.; Levi, Ronald J.; Leitner, Jr., George Lewis, Adjustable anti-tip wheels for power wheelchair.
Degonda Andre,CHX ; Wuthrich Thomas,CHX, Wheelchair for transporting or assisting the displacement of at least one user, particularly for handicapped person.
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