Longitudinal Velocity Estimation in Single-Track Vehicles

Vehicle dynamics control systems are becoming available for single-track vehicles. The dynamics of single-track vehicles have some unique features that require ad hoc solutions. One of the most critical aspects is the estimation of the vehicle body velocity. In this paper the problem of estimating the body velocity of a two wheeled vehicle for traction control applications is discussed. The front wheel velocity and the longitudinal acceleration measurements are used to estimate the vehicle velocity according to a sensor fusion philosophy. The complementary filter approach is compared against a more advanced Kalman filter. It is shown that the mentioned Kalman filter can be written as a second order complementary filter; this allows to derive quantitative guidelines for the tuning of the filter. The proposed methods are shown to be more robust to wheelies than the front wheel velocity based estimate. Experimental tests on an instrumented bike validate the methods for traction control applications.