Dynamic model and balanced lateral rolling motion control of a unicycle robot

Dynamic model of a unicycle robot with three driven joints and controller to achieve its balanced lateral rolling motion was studied in this paper. With regard of the nonholonomic constraints, we established a dynamic model for the robot by use of Chaplygin equation. The modeling results revealed that there were 6 general velocities and 3 underactuated freedoms in the system. We considered the dynamical subsystem of the robot´s balanced lateral rolling motion, and developed a controller for it by applying the principle of Partial Feedback Linearization. The controller was designed by linearizing the underactuated rolling angle of the frame, and taking the rolling angle and the rotating angle of the balance regulating flying-wheel as output. Numerical simulation together with prototype experiment were given at the end to testify the availabilities of the proposed dynamic model and the motion controller.