A feedback control scheme for reversing a truck and trailer vehicle

Claudio Altafini, Alberto Speranzon and B. Wahlberg

IEEE Transactions on Robotics and Automation, 17(6):915-922, December 2001.

A control scheme is proposed for stabilization of backward driving along simple paths for a miniaturized vehicle composed of a truck and a two-axle trailer. The paths chosen are straight lines and arcs of circles. When reversing, the truck and trailer under exam can be modeled as an unstable nonlinear system with state and input saturations. The simplified 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. In fact, the system cannot be driven backward from all initial states, because of the jack-knife effects between the parts of the multibody vehicle, sometimes it is necessary to drive forward to enter in a specific region of attraction. This leads to the use of hybrid systems models and switching control. 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.

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