Road friction effect on the optimal vehicle control strategy in two critical manoeuvres

Artikel i vetenskaplig tidskrift, 2014

This paper presents a research study on the optimal way to negotiate safety-critical vehicle manoeuvres depending on the available actuators and road friction level. The motive is to provide viable knowledge of the limitations of vehicle capability under the presence of environmental preview sensors. In this paper, an optimal path is found by optimising the sequence of actuator requests during the manoeuvres. Particular attention is paid to how the vehicle control strategy depends on friction. This study shows that the actuation of all the forces and torques on and around the vehicle centre of gravity is approximately scaled with friction, whereas at individual wheel level, the optimal force allocation will differ under different friction conditions. A lower friction level leads to lower velocities and load transfer, which influences the individual wheels’ tyre force constraints. However, the actuator response compared to the whole system is increased at a lower friction level.