Passivity-based Model Free Control of an Omnidirectional Mobile Robot

This paper presents a passivity-based trajectory tracking controller for an omnidirectional mobile robot, based on a modified generalized proportional integral observer. In contrast to traditional feedback linearization methods, the design objective of our approach is to design a controller such that the passivity property of the robot is preserved in the closed-loop system. The resulting control system could be very attractive from a practical point of view, since the inertia matrix and coriolis matrix of the robot dynamic model are not required. The robot geometrical information is the only required model information, which can be easily obtained in practical applications. Moreover, only position measurements are used. In addition, the closed-loop stability property is analyzed. Comparisons with traditional PID control have been conducted through simulations to show the effectiveness of the proposed control approach.