A feedback control scheme for reversing a radio-controlled truck andtrailer vehicle

Claudio Altafini, Stokholm, Sweden, Royal Institute of Technology

A control scheme is proposed for backward motion stabilization of a vehicle composed of a truck and a two-axle trailer.

When reversing, the truck and trailer under exam can be modeled as an unstable nonlinear system with state and input saturations. The reduced goal of stabilizing along a trajectory (instead of a point) allows to consider a system with controllable linearization. Still, the combination of instability and saturations makes the task impossible with a single controller. The scheme proposed here consists of a switching controller with a logic variable (the sign of the longitudinal velocity input) that allows switching between backward (open loop unstable) motion and forward (open loop stable) motion, each of them governed by linear feedback designed on the corresponding Jacobian linearization. A suitable choice of the switching surfaces gives to the desired trajectory the character of global attractor. The scheme has been implemented and successfully used to reverse the radio-controlled vehicle.