LAUSR

Abstract This article deals with the coordinated motion and powertrain control of a series-parallel hybrid 8 × 8 vehicle equipped with mechanical transmission and electric wheels. With six wheels driven by in-wheel motors and two driven by an AMT, the 8 × 8 vehicle has enormous potential to improve its dynamic performance, fuel economy, off-road mobility, maneuverability, gradeability, etc. On the other hand, as vehicle motion dynamics and powertrain components are closely coupled in the complex hybrid system, appropriate control strategy is urgently desired to deal with the torque distribution problem. Continuous control variables such as wheel torque, engine torque, generator torque, and discrete variable like transmission gear should be determined properly to achieve optimum control of the vehicle. A hierarchical control strategy constructed by tracking controller and allocation algorithm is proposed. Integral sliding mode control is adopted in the upper layer to track desired vehicle planar motion. The allocation problem is handled by a three-step control allocation algorithm based on quadratic programming, with carefully consideration of vehicle and powertrain features. Co-simulations with Matlab/Simulink® and TruckSim® show that the proposed coordinated control approach is capable of controlling vehicle planar motion and managing the complex series-parallel hybrid system simultaneously.