CPC B62M 6/50 (2013.01) [H02K 7/14 (2013.01); H02K 11/21 (2016.01)] | 20 Claims |
1. A bicycle electric power assist device, comprising:
an electric motor connected in a torque transmitting relationship to crank arms or a crankshaft driven by a pedal force from pedals via the crank arms;
a battery to be mounted on a bicycle to serve as a power supply for the electric motor;
a control unit configured to control operation of the electric motor;
a rotation angle sensor configured to detect a crank rotation angle position of the crankshaft; and
a current sensor configured to detect a motor current of the electric motor,
wherein the control unit comprises:
a pedal force estimation/calculation unit configured to estimate the pedal force from a difference between the motor current in a first crank rotation angle position and the motor current in a second crank rotation angle position which is different from the first crank rotation angle position; and
a motor drive control unit configured to control driving of the electric motor according to the pedal force estimated by the pedal force estimation/calculation unit.
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