Controlling active cabin suspensions in commercial vehicles

The field of automotive suspensions is changing. Semi-active and active suspensions are starting to become viable options for vehicle designers. Suspension design for commercial vehicles is especially interesting given its potential. An active cabin suspension for a heavy-duty truck is considered, consisting of four ideal actuators with parallel springs, one acting on each corner of the cabin. The main question is how to control this suspension such that it gives optimal comfort when driving in a straight line, but still follows a specified compensation strategy when cornering, braking or accelerating. The proposed controller uses modal input-output-decoupling. Each of the modes has a separate controller including: a skyhook part for enhanced comfort; and an event part for attitude control. The proposed control strategy is tested in simulation using a validated tractor semi-trailer model with idealized actuators. It is shown that driver comfort can be greatly enhanced, without impairing the attitude behavior of the cabin. Furthermore, in contrast to what is known from quarter car analysis, it is shown that adding passive damping is highly desirable.