Wheel slip control for the electric vehicle with in-wheel motors: variable structure and sliding mode methods

The article introduces four variants of the controller design for a continuous wheel slip control (WSC) system developed for the full electric vehicle equipped with individual in-wheel motors for each wheel. The study includes explanation of the WSC architecture, design of controllers, and their validation on road tests. The investigated WSC design variants use variable-structure proportional-integral, first-order sliding mode, integral sliding mode controllers as well as continuous twisting algorithm. To compare their functionality, a benchmark procedure is proposed based on several performance factors responsible for driving safety, driving comfort, and control quality. The controllers are compared by the results of validation tests done on low-friction road surface.