Robust Vehicle Speed Limiter Using Disturbance and Speed Observer

This paper presents a practical approach to developing a speed limiter using a disturbance observer (DOB) and a speed observer. A nominal plant model is designed assuming that the vehicle is a lumped mass. The plant uncertainty and external disturbance are lumped into a disturbance term and compensated for by the DOB. With the contribution of the DOB, the proposed controller can reduce overshoot and minimize steady-state error without feedforward and integrator control. In addition, the speed observer is also designed to reduce the overshoot due to noise such as offset, lag, and communication delay between the display speed and wheel speed, because the proposed controller operates according to the display speed. The proposed controller was validated by vehicle experiments performed on a C-segment hybrid electric vehicle (HEV) and achieved superior performance compared to conventional controllers.