Feedback Linearization Tracking Control of Vehicle Longitudinal Acceleration Under Low-Speed Conditions

This research addresses the modeling, design, and implementation of a longitudinal acceleration tracking control (LATC) system for a test vehicle at low speeds. An electronic throttle actuator for LATC system application is introduced first, which can be used to perform the switching of three functions arbitrarily: automatic LATC, manual drive-by-wire, and pure manual operation. Then, a nonlinear dynamics model for the test vehicle is proposed by using a state-space equation, and several major nonlinear components including the engine, torque converter, transmission, and electronic throttle actuator are considered simultaneously in this model. Furthermore, focusing on the electronic throttle actuator, the strong nonlinear factors induced by the Coulomb friction and torsion of the return spring are analyzed. In view of the nonlinearity of the proposed model, the concept of feedback linearization is employed to convert the nonlinear system into a linear canonical form, and the analysis of the stability caused by the model’s uncertainty is also discussed. Finally, an acceleration feedback linearization controller and a Kalman filter are introduced. They adopt the linear canonical form, which represents a simpler structure. The performance in tracking desired acceleration at low speeds is confirmed by both computer simulations and experiments.