Terrain and Traffic Optimized Vehicle Speed Control

The paper considers optimal control of vehicle speed when the vehicle is driven in a particular geographic region with specific terrain and traffic patterns. The vehicle route is assumed to be unknown in advance. The properties of the terrain and traffic flow are modeled stochastically. A method is proposed for constructing a control policy off-line to optimally prescribe vehicle speed set-point as a function of current driving conditions, for best on average fuel economy and travel speed performance. A related method is proposed to evaluate expected average fuel economy and travel speed performance of sub-optimal control policies, such as the policies which use constant speed offset relative to average traffic speed. The optimal control law which prescribes vehicle speed set-point can be deployed in advanced vehicle cruise control systems or incorporated into a driver advisory function. In addition, the value function of optimal or suboptimal control policies may be used as a terminal cost in a receding horizon optimization of vehicle speed over routes with known initial segments, or for fuel efficient vehicle routing.