Patent ID: 9114711
Filing Date: 2015-08-25
Classification: B60K,B60L,Y02T

Abstract:
1. An electric vehicle comprising: a motor unit configured to drive a drive wheel; a motor control circuitry configured to control the motor unit in accordance with a motor torque command value that is generated based on commands produced from an acceleration manipulation unit and a deceleration manipulation unit; a slip ratio estimator configured to estimate a slip ratio of the drive wheel on a road surface based on a detection value indicating a travel speed of the vehicle and a rotational frequency of the drive wheel; an applied torque estimator configured to estimate an entire torque applied to the drive wheelbased on (i) the motor torque command value or a motor current value of the motor unit and (ii) the torque estimated by a disturbance observer that is attributable to external force; a coefficient of friction estimator configured to estimate a coefficient of friction between a road surface and a tire of the drive wheel, based on the torque estimated by the applied torque estimator and the slip ratio estimated by the slip ratio estimator; and a motor torque command value limiter configured to limit, based on a determined maximum acceptable torque, the motor torque command value to the motor unit that is generated responsively to the acceleration manipulation unit and the deceleration manipulation unit.