Braking torque control for parallel hybrid electric truck

This paper presents two braking torque control strategies for parallel powertrains of hybrid duty truck. First, a coordinated braking control scheme is constructed with three parts: braking torque distribution, feedforward compensation with the air-over-hydraulic brake, and feedback compensation with electric motor based on estimated braking torque. A simple delay controller to compensate braking torque is designed for braking with gear shifting process described in the first strategy. The second strategy is proposed using pressure between synchroniser gears as additional feedback control input to compensate the loss of braking torque for braking with gear shifting process. Switching controllers will be proposed to synthesise braking process for the two processes. And then convergence analysis for proposed two control strategies will be given based on simplified model. Finally, simulation results which was conducted on a physically scaled hybrid duty truck are demonstrated to verify the effectiveness of proposed control strategies.