Off-Line Optimization Based Active Control of Torsional Oscillation for Electric Vehicle Drivetrain

Abstract

Abstract:As there is no clutch or hydraulic torque converter in electric vehicles to buffer and absorb torsional vibrations. Oscillation will occur in electric vehicle drivetrains when drivers tip in/out or are shifting. In order to improve vehicle response to transients, reduce vehicle jerk and reduce wear of drivetrain parts, torque step changes should be avoided. This article mainly focuses on drivetrain oscillations caused by torque interruption for shifting in a Motor-Transmission Integrated System. It takes advantage of the motor responsiveness, an optimal active control method is presented to reduce oscillations by adjusting motor torque output dynamically. A rear-wheel-drive electric vehicle with a two gear automated manual transmission is considered to set up dynamic differential equations based on Newton's law of motion. By linearization of the affine system, a joint genetic algorithm and linear quadratic regulator method is applied to calculate the real optimal motor torque. In order to improve immediacy of the control system, time consuming optimization process of parameters is completed off-line. The active control system is tested in AMEsim ® and limitation of motor external characteristics are considered. The results demonstrate that, compared with the open-loop system, the proposed algorithm can reduce motion oscillation to a satisfied extent when unloading torque for shifting.

Simulation Model and Method for Active Torsional Vibration Control of an HEV

“…Hybrid electric vehicles (HEV) have been widely adopted by the automotive industry as a practical solution to increasing fuel efficiency and extending driving range [1][2][3][4][5][6][7][8]. However, because the configuration is more complicated, if the design is not properly executed torsional vibration problems are more likely to occur, such as torsional damper damage and broken shafts, but it also provides a new means for torsional vibration control [9][10][11].…”

Adaptive torsional vibration active control for hybrid electric powertrains during start-up based on model prediction

“…Kim et al 18 designed an anti-vibration shock controller, which was composed of an active damping method that generates a reverse torque that is opposite to the vibration phase and a torque profile method that limits the torque gradient. Besides, Awadallah et al, 19 Yang et al, 20 and Liu et al 21 also used the motor torque compensation method to improve the shift quality of HEV.…”

“…To compensate for the sluggish response in the transmission system, this approach utilizes the quick response characteristic of motor torque. [17][18][19][20][21] For example, Chen et al 17 used the motor to generate compensation torque to offset the fluctuation torque of the engine, and realized the active control of the engine torque fluctuation by using the observer inputted by the crankshaft speed to solve the vibration during the engine start and stop in the neutral state question. Kim et al 18 designed an anti-vibration shock controller, which was composed of an active damping method that generates a reverse torque that is opposite to the vibration phase and a torque profile method that limits the torque gradient.…”

Optimal Clutch Pressure Control in Shifting Process of Automatic Transmission for Heavy-Duty Mining Trucks

“…e linear-quadratic optimal regulator (LQR) has been used in the field of vehicle powertrain system control successfully. To reduce the torsional vibration of electric vehicle transmission systems, the method of an infinite-time LQR was proposed by Lin et al [13] to adjust the output torque of the drive motor dynamically. Gao et al [14] used an offline finite-time LQR to track the clutch relative speed during the gear shift of an electric vehicle equipped with AMT.…”