Control Algorithm Development for Independent Wheel Torque Distribution with 4 In-wheel Electric Motors

Electronic Stability Control (ESC) devices are going to become mandatory in the near future. Moreover, the high price of the electronic sensors makes engineers to build its active safety systems based on the knowledge of a reduced number of real vehicle states, while the rest must be estimated from the real ones. In this case, the new possibilities offered by an independently controlled wheel traction system are explored. The advantages enable to easily implement anti-lock braking and traction control systems, chassis motion control like Direct Yaw Control (DYC) and an estimation of road surface condition. Hence, yaw moment reference signal is possible to be followed not only by braking, but also by giving an increasing torque to wheels in order not to lose any global vehicle velocity. Fault-tolerant strategies are also covered for the dynamic behaviour to be appropriately adapted to an electrical fault. An electronic differential strategy is implemented in both axles in order to develop an active help to curve performance.