This article describes a novel automatic steering system for a 30.73m long double articulated bus equipped with three independent steer-by-wire axles. Two model-based control design approaches are proposed. The first approach uses a kinetic vehicle model to design a train-like guidance system and a force-canceling that avoids excessive mechanical stress in the joints and the chassis.
While the first approach requires high computational efforts, the second approach utilizes a kinematic model to design an extended Ackermann-steering system that performs well on available electronic control units (ECU).
Multi-body-system (MBS) simulations show that both approaches offer high tracking performance and low mechanical stress in the chassis of the vehicle. Furthermore, road tests with the prototype AutoTram® Extra Grand confirm the simulation results.