Vibration suppression control of an integrated powertrain of electric and hybrid vehicles using LQR controller and reduced-order observer

This paper presents a vibration suppression control method for a motor-gearbox directly coupled integrated powertrain of electric and hybrid vehicles. The integrated powertrain is modeled as a two-mass system. Based on the analysis of the system dynamics, the oscillation of torsional angle and relative speed difference needs to be controlled to improve driving performance. To this end, an optimal LQR controller with a reduced-order observer is proposed to suppress the vibration caused by the oscillation of torsional angle in the system. A computer simulation model is developed to verify the effectiveness of the proposed control scheme. The simulation results illustrate that the estimated states are close to the reference states. It is also shown that the oscillation of the system is significantly suppressed. And both torsional angle and relative speed difference are well controlled under different gear ratios, which is beneficial for enhancing shift quality. Therefore, the proposed vibration control scheme is suitable for the integrated powertrain of electric and hybrid vehicles.