Stability region estimation of statically unstable two wheeled mobile robots

Most of the research so far on two wheeled mobile robots is on the control of the robot body. However when a robot is implemented in real environment the range of initial conditions of different states of the robot need to be known for safe operation. This paper presents the estimation of safe region of initial conditions of states for a statically unstable two wheeled mobile robot using a standard Lyapunov direct method. The method uses a known Lyapunov Function. Variation of stability region with the Lyapunov functions requires the selection of a good Lyapunov function for a system. Twotypes of Lyapunov functions, Quadratic and Energy based were formulated. The simulation results for the stability regions were evaluated using these Lyapunov functions and were compared with true region, determined using ode solver. A Lyapunov function that showed less conservative stability region was selected to show the theoretical stability region. The experiments verified the results.