To improve the operability, by constituting an electric wheelchair of a motor connected to a wheel via a reduction mechanism having a low back drive torque and a control circuit, which judges the output of a torque sensor, makes an electric current flow then the output value reaches a prescribed value or more, and drives the motor.
A back electromotive voltage detection circuit 70 detects the back electromotive force of a motor 21 and outputs a back electromotive voltage signal and positive and negative directional signals to a processor 60. When all of four switching elements EFTa63-EFTd66 are in high impedance states, polarity and voltage proportional to the rotational direction and rotational speed are generated between terminals of the motor 21. When the back electromotive force is applied from the input connected between the terminals and if the voltage polarity is positive, a photocoupler on the positive directional signal side is operated and the intensity of the voltage is outputted to the back electromotive voltage output at the same time of turning ON the positive directional signal. In a case of being negative, a photocoupler on the negative directional signal side is operated and the intensity of the voltage is outputted to the back electromotive voltage output as a rectified positive voltage at the same time of the turning on the negative directional signal.
NAKAMURA HARUJI
INOUE TOSHITOKI
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