Impedance Estimation and Motion Control of a Pendulum-Driven Spherical Robot

Spherical robot due to its special attributes such as maneuverability, omnidirectional movement, and silent movement has employed in the robotic fields instead of using legged and wheeled robots. In spite of the fact that several mechanisms are used to design such robots, pendulum driven is commonly utilized because of its simplicity. In this paper, a spherical robot equipped with a pendulum - driven is implemented. Two ways of control are discussed. At first, the robot is controlled manually by using smartphone remotely. In another strategy, schemes of control are designed to guarantee the trajectory tracking and stability of the robot autonomously. The former strategy is divided into two plans. At first, the mathematical dynamics model of the robot based on the Lagrangian method is proposed. As well as, the transform functions between the driving motors and angular velocities are derived experimentally. PID control is employed to ensure the trajectory tracking of the robot in both strategies. Experimental results prove the effectiveness of the transform function compared to the mathematical dynamic model.