Hybrid Dynamic Optimization for Cruise Speed Control

• Author(s): Jorge, Tiago R. ; Lemos, João M. ; Barão, Miguel ; Bemporad, Alberto
• Date: 2011
• Persistent ID: http://hdl.handle.net/10174/4703
• Origin: Repositório Científico da Universidade de Évora
• Subject(s): Control; Hybrid Systems; Optimization; Automotive Control
• Document Type: Article
• Language: English

Description

The cruise control problem of transferring the speed of a vehicle between two values in a fixed interval of time using a predefined sequence of gears is solved in this paper. This is a hybrid dynamic optimization problem since the control variables include both a continuous variable (fuel flow) and a discrete variable (the gear to apply at each instant). The solution is given in the form of a hybrid optimal control algorithm that computes the optimal switching times between gears using Dynamic Programming and the optimal fuel profile between successive gear boundaries using a gradient algorithm to approximate the optimum conditions. In order to reduce the search of the optimal switching times to a search in a finite dimension graph, a procedure based on a changing grid is used. The algorithm is illustrated by a simulation using a diesel one-dimensional car model.