Pedal assist sensor

摘要

Apparatus and method for controlling an electric motor providing assistance to a bicycle rider based on measuring the mechanical power generated by the rider. The power generated by the rider is measured by measuring tension in a bicycle chain (or belt) and RPM. A chain (or belt) roller is carried at the free end of a cantilevered beam and the chain (or belt) rides over the roller. The resulting deflection of the cantilevered beam provides a measurement of chain tension. A control signal for the electric motor is generated based on a smoother version of the power generated by the rider.

主权项

1. A motor control system for an electric bicycle comprising:
an electric motor for assisting a rider pedaling the bicycle; a mechanical power transfer apparatus comprising a belt or a bicycle chain; a deflection sensor measuring tension in the mechanical power transfer apparatus to generate tension data, the deflection sensor comprising a displacement transducer and a cantilevered beam, and the tension data is related to a deflection of the cantilevered beam measured by the displacement transducer; a processor computing:
tension data of the belt or bicycle chain from the deflection of the cantilevered beam;peak torque events in the tension data;Revolutions Per Minute (RPM) of a crank assembly by counting two peak torque events as one revolution;pedal torque data from the tension data;power from the RPM and the torque; anda control signal for the electric motor proportional to the power generated by pedaling.