Optimal control of regenerative hydraulic composite braking system based on a voltage variable charging control scheme

摘要

A double-loop optimal control strategy combined with a voltage variable charging control scheme is developed to enhance the efficiency of energy recovery and improve control precision for a regenerative hydraulic composite braking system. The proposed voltage variable charging control scheme structure aims to regulate a regenerative braking torque using a charging voltage variation based on an existing battery management system. In addition, an experimental test was conducted to verify the effectiveness of the charging voltage control, and a first loop optimal control was developed to evaluate the ideal ground braking force accurately by transforming several state variables into differential equations. A second optimal control loop was subsequently developed to track an ideal slip ratio using a full-information optimal sliding mode control method under the all-braking conditions. Simulation results corroborate that a composite braking system controlled by the proposed control strategy can implement the regenerative braking behavior precisely with a considerable high-energy recovery efficiency.