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US 6,354,390 B1Granted
Power assisted wheelchair
AssigneeYamaha Hatsudoki Kabushiki Kaisha
InventorsAtsushi Uchiyama, Hiroaki Ogata
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AssigneeYamaha Hatsudoki Kabushiki Kaisha
InventorsAtsushi Uchiyama, Hiroaki Ogata
Estimating the term…
An electric power assisted, manually operated vehicle such as a wheelchair. A force sensor senses the manual input force and the power assist is generated in response to the sensed input force. A number of embodiments are disclosed wherein the amount of assist is varied in response to running conditions and/or operator conditions so as to improve the performance. In many of these embodiments, the assist is greater at low speeds and is held constant at higher speeds and then decreased as the speed exceeds a predetermined high speed. In some of these embodiments, a regenerative braking is also applied in the event the vehicle speed becomes excessive. Also, the null or dead band range of the sensor is adjusted so as to provide a wider range when stationary than when running. This decreases sensitivity for startup and yet provides good response during running.
An electric motor, power assisted wheelchair having a frame assembly providing a seat for accommodating a single rider, a pair of drive wheels disposed on opposite sides of said seat and having hand wheel portions for application of a manual force by a rider for turning said drive wheels, an electric motor for providing a diving assist force to at least one of said drive wheels for assisting manual force input, a source of electrical power for said electric motor, a force sensor for sensing manual force input from the rider to said hand wheel, a control for receiving an output from said force sensor and controlling the amount of electric power transmitted from said source of electrical power to control the amount of power-assist from said electric motor in relation to the sensed manual force input, means for sensing a wheelchair running condition and means in said control for varying the amount of electric power transmitted from said source of electrical power to control the amount of power assist provided by said electric motor in response to the sensed wheelchair running condition.
An electric power assisted, manually propelled vehicle, said vehicle having a propulsion device for propelling said vehicle, a manual power input mechanism for applying manual power to said propulsion device for manually powering said vehicle, an electric motor operatively coupled to said vehicle propulsion device for applying an assist power to the propulsion device, a source of electrical power for said electric motor and a control for sensing the manual input force and vehicle speed for controlling the amount of electrical power transmitted from said source of electrical power to said electric motor, said control being effective to stop said power assist if said vehicle speed exceeds a first predetermined speed and apply a braking force to said vehicle through said electric motor by means of regenerative braking if the speed exceeds a second predetermined speed higher than said first predetermined speed.
An electric power assisted, manually propelled vehicle, said vehicle having a propulsion device for propelling said vehicle, a manual power input mechanism for applying manual power to said propulsion device for manually powering said vehicle, an electric motor operatively coupled to said vehicle propulsion device for applying an assist power to the propulsion device, and a control for sensing the manual input force and vehicle speed for controlling said electric motor, said control including a manual input sensor having a null or dead band condition wherein a predetermined amount of force must be exerted before the electric power-assist is applied said control adjusting said null or dead band range to be wider before said vehicle is in motion and once said vehicle is in operation, the width of the null or dead band is decreased by said control so as to provide quicker response.
Dependencies are inferred from the claim text.