Exploiting autonomous corner modules to resolve force constraints in the tyre contact patch

Journal article, 2008

This paper presents a general force allocation strategy for over-actuated vehicles, utilising technologies where tyre forces can be more
freely controlled than in conventional vehicles. For the purpose of illustration, this strategy has been applied and evaluated using a
design proposal of an autonomous corner module (ACM) chassis during a transient open-loop response test. In this work, the vehicle has
been forced to follow a trajectory, identical to the performance of a conventional front-steered vehicle during the manoeuvre studied. An
optimisation process of tyre force allocation has been adopted along with tyre force constraints and cost functions to favour a desired
solution. The vehicle response has been evaluated as open-loop, where tyre forces are shown to be allocated in a different manner
than in conventional front-steered vehicles. A suggested approach for a control scheme of steering actuators is presented, where the
actuator limitation is related to the lateral force possible. Finally, the force allocation strategy involves the ability to control vehicle
slip independently from vehicle yaw rate. This opportunity has been adapted in the ACM vehicle in order to relax vehicle slip from the
original trajectory description. In such circumstances, the ACMs demonstrate better utilisation of the adhesion potential.