Yamaha Hatsudoki Kabushiki Kaisha

Hiroaki Ogata

Atsushi Uchiyama

Masaya Suenari

Nobuo Hara

Mikio Saito

Kenji Tokura

At Step Sb a duty factor, which was calculated at Step Sb on the basis of a data for a feed-back control, is compared with a limit value of the duty factor. If the duty factor is less than the limit value, a pulse for the PWM control is modulated to have the calculated duty factor at Step Sb If the duty factor is greater than the limit value, the pulse for the PWM control is modulated to have the duty factor of the limit value at Step Sb Accordingly, the duty factor provided for a current value instruction is not in excess of the limit value, so that the secondary battery is prevented from discharging overcurrent in excess of the limit current which can be discharged from the secondary battery. Accordingly, although the capacitance of the secondary battery is not large, the lifetime of the secondary battery is prevented from being shortened.

Overcurrent protection device

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.

Power assisted wheelchair

Wheel chair with auxiliary power

A power-assisted wheelchair wherein the power-assist for the wheels is based upon the manual force exerted on both of the wheels. The power-assist is continued for a brief time period after manual power input is stopped. The continuing assist is provided equally to each wheel so that the wheelchair will coast in a straight direction. The wheels of the wheelchair are readily detachable with the backing plate prime mover and transmission for driving the wheel.

Electric power-assisted wheelchair

Control device for direct current electric motor

Growing community of inventors

Iwata, Japan

Hiroaki Ogata