Controller for vehicle for accurate speed estimation

摘要

A motor vehicle 100 is provided with control means operable to measure a speed of travel of the vehicle 100 over a surface. The measurement is responsive to a measured speed of a driven wheel. When it is required to verify measured vehicle speed the control means automatically reduces an amount of torque applied to at least one of a plurality of driven wheels111-114 and measures a speed of rotation of the wheel whilst the applied torque is reduced; and updates a stored speed value corresponding to a speed of the vehicle 100 over the ground. The control system determines following a reduction in torque applied to the wheel 111-114 that the vehicle speed is consistent with one or more speed measurements made by alternative means, e.g. accelerometer. A controller 140 comprises the control means and a method of operation is disclosed which is particularly suited to vehicles having four electric wheel motors 111M-114M. This provides improved accuracy of speed estimation during acceleration when slip may occur.