Bounded Smooth Time Invariant Motion Control of Unicycle Kinematic Models

This paper presents a new curvature based smooth time invariant control law for posture regulation and path following control of unicycle type kinematic models. The control law is developed in polar coordinates for posture regulation using nonlinear Lyapunov techniques and extended for path following via waypoint navigation techniques. The algorithm is then applied to a two-axle compliant framed modular mobile robot. To this goal the complex robot kinematics are reduced to an equivalent unicycle kinematic model where we must consider physical constraints on wheel velocity and frame curvature. Bounded curvature and velocity expressions are thus derived as control inputs. The controller is then extended to compensate for non-ideal initial conditions and drift. Simulation and experimental results evaluate algorithm performance.