Path following with reduced off-tracking for the n-trailer system

The path following problem for a nonholonomic kinematic mobile robot towing trailers is addressed. The task is to keep the whole vehicle, not just a single guide-point, to a minimal distance from the path, i.e. to reduce the off-tracking of the vehicle with respect to the path. This is achieved by keeping track of the error distance of each of the middle points of the axles of the vehicle from the path using different moving frames. Local exponential stability is guarantee by a dynamic controller based only on the sum of these error distances.