Efficient hierarchical robust adaptive control of mode transition for parallel hybrid electric vehicles

Abstract

A fast and smooth mode transition process for parallel hybrid electric vehicles (HEVs) can improve vehicle drivability. At the same time, system uncertainty resulting from friction, gearbox, parameter perturbation, production deviations, and external disturbance of the mode transition process makes control design challenges. In this regard, this paper introduces a novel efficient hierarchical robust adaptive mode transition control strategy to achieve an accurate and fast engagement of the clutch of a parallel HEV during mode transition in the case of uncertain system parameters and unmeasurable actual clutch torque in this paper. At the upper level of the controller, a robust adaptive sliding mode control (RASMC) is proposed to calculate the clutch transmitted required torque based on the current states of the electric motor (EM) and engine, and the control parameters are optimized via the particle swarm optimization (PSO) algorithm by compromising the vehicle jerk and the clutch slipping energy loss. Moreover, a fuzzy controller is designed to calculate the expected clutch engaging speed by employing the deviation of the desired and actual clutch torques, and the actual clutch torque is not a measured value but an estimate obtained by a proportional-integral (PI) observer. At the lower level, an adaptive finite-time control (AFTC) scheme is developed to overcome the gear backlash, parameter perturbation, and external disturbance during the clutch position tracking process. The effectiveness and advantage of the proposed control strategy are verified by both MATLAB/Simulink simulations and the hardware-in-loop (HIL) test.

Robust adaptive control for hybrid electric vehicles using sliding mode control

“…According to the EM dynamic equations ( 10) and (11), the tracking error between the actual i d , i q and the desired current signals i…”

“…8,9 In addition to the above energy management strategies, many studies have been carried out for the mode transition process via torque-coordinated control between the engine and EM to improve smoothness and efficiency in the face of uncertain parameters and external disturbances. For instance, adaptive control strategy with hierarchical control technique, 10,11 robust sliding control strategy, 12 dynamic coordinated control strategy 13 and optimized control strategy 14 all achieve driving performance during the mode transitions. However, these control methods mentioned did not consider the issue of accurate torque or speed tracking.…”