OptimalSpeed Controller for a Heavy-Duty Vehicle in the Presence of SurroundingTraffic

Abstract: This thesis has explored the concept of an intelligent fuel-efficient speed controller for a heavy-duty vehicle, given that it is limited by a preceding vehicle. A Model Predictive Controller (MPC) has been developed together with a PI-controller as a reference controller. The MPC based controller utilizes future information about the traffic conditions such as the road topography, speed restrictions and velocity of the preceding vehicle to make fuel-efficient decisions. Simulations have been made for a so called Deterministic case, meaning that the MPC is given full information about the future traffic conditions, and a Stochastic case where the future velocity of the preceding vehicle has to be predicted. For the first case, regenerative braking as well as a simple distance dependent model for the air drag coefficient are included. For the second case three prediction models are created: two rule based models (constant velocity, constant acceleration) and one learning algorithm, a so called Nonlinear Auto Regressive eXogenous (NARX) network. Computer simulations have been performed, on both created test cases as well as on logged data from a Scania vehicle. The developed models are finally evaluated on the test cases for both varying masses and allowed deviations from the preceding vehicle. The simulations show on a potential for fuel savings with the MPC based speed controllers both for the deterministic as well as the stochastic case.