Adaptive Control System based on Lineal Control Theory for the Path-Following Problem of a Car-Like Mobile Robot

The objective of this paper is to design a path following control system for a
car-like mobile robot using classical linear control techniques, so that it adapts on-line to
varying conditions during the trajectory following task. The main advantages of the proposed
control structure is that well known linear control theory can be applied in calculating the PID
controllers to ful l control requirements, while at the same time it is
exible to be applied in
non-linear changing conditions of the path following task. For this purpose the Frenet frame
kinematic model of the robot is linearised at a varying working point that is calculated as
a function of the actual velocity, the path curvature and kinematic parameters of the robot,
yielding a transfer function that varies during the trajectory. The proposed controller is formed
by a combination of an adaptive PID and a feed-forward controller, which varies accordingly with
the working conditions and compensates the non-linearity of the system. The good features and
exibility of the proposed control structure have been demonstrated through realistic simulations
that include both kinematics and dynamics of the car-like robot.