US Patent 8672081 Power assisted vehicle

A power assisted vehicle includes a wheel drive unit that transmits power of a motor as assist power to wheels via clutches capable of connecting and disconnecting power transmission, input rotation angle detection units that detect rotation angles of input shafts of the clutches, output rotation angle detection units that detect rotation angles of output shafts of the clutches, and assist power calculation units that calculate the relative angle difference between the rotation angles of the input shafts of the clutches and the rotation angles of the output shafts of the clutches, and while clearing the relative angle difference in a predetermined period, calculate the assist power on the basis of the relative angle difference before it is cleared.