Improvement of Mobility for In-Wheel Small Electric Vehicle with Integrated Four Wheel Drive and Independent Steering: A Numerical Simulation AnalysisDownload PDF
Similar to conventional vehicle, most in-wheel small electric vehicles (EV) that exist today are design with understeer (US) characteristic. We believe that oversteer (OS) design approach for in-wheel small EV can increase the steering response and lower the steering input. However, one disadvantage of OS characteristic is that it has a stability limit velocity. In this paper, we proposed a Four-Wheel Drive and Independent Steering (4WDIS) for in-wheel small EV with OS characteristic. The aim of implementing 4WDIS is to develop a high steer controllability and stability of an in-wheel small EV at any velocity. The 4WDIS is govern by an Intelligence Steering Control System (ISCS) that evaluates the dynamics of the EV, the surrounding condition, the road surface and vehicle stability in response to the drivers driving input. This paper analyses the steering performance of 4WDIS on an OS in-wheel small EV by using numerical simulation. The objective of the simulation is to model a control method for the 4WDIS by the ISCS based on the behavior of the OS in-wheel small EV before we can implement on an actual vehicle. The results show by implementing 4WDIS, an OS in-wheel small EV can achieve high cornering performance below the critical velocity while maintaining stability at high speed.
Keywords: In-wheel small electric vehicle, Four wheel drive and independent steering, Oversteer characteristic, Understeer characteristic, Stability limit velocity, Numerical simulation