A family of spherical mobile robot: Driving ahead motion control by feedback linearization

The driving ahead motion problem was considered for a family of spherical mobile robot which utilizes counter-weight pendulum motion for propulsion mechanism. A simplified dynamic model of driving ahead motion of the system was derived with respect to the drive motor torque as input, and the input-state linearization condition was checked. Based on this result, a full feedback linearization of the system was obtained. The resulting equations were then used to design two novel controllers. The first one was used to control the angular velocity of the shell within an acceptable rang. The second controller was utilized to keep the angle of the shell between the specified limits. Simulation results are provided to show the efficacy of the controllers using realistic data. Experimental results are presented where the controllers are implemented on a spherical robot, BYQ_III, which is developed in our laboratory. The experimental results show that the robot converges to a neighborhood of the desired angular velocity and angle within the acceptable stationary errors.