Dynamics Control of Pendulums Driven Spherical Robot

Abstract

The pendulum driven spherical robot exhibit unique dynamic behavior which designed for reconnaissance and unstructured hostile environment exploration. Unfortunately spherical type robot maneuvering is nonlinear to get the desired part, internal propulsion mechanism and motion control need to be reconciled. This is a mechanical challenge to get in balancing and weight distribution. The robot has three DOFs and single inputs, of which the nature is a nonlinear and under actuated system with non-holonomic dynamic constraints. The enhanced construction of two sections on pendulums joint offers novel motion principle of spherical robot, which is moving simultaneously actuated by eccentric moment and inertial moment generated by this pendulum. Meanwhile the mobility is enhanced when the robot behaves dynamically. The dynamic model of linear motion is formulated on the basis of Lagrange equation, and a smooth trajectory planning method is proposed for linear motion. A feedback controller is build to ensure the accurate trajectory planning. Turning in place motion is an indispensable element of omni directional locomotion which can enhance the mobility of spherical robots. The dynamic model is derived using the theory of moment of momentum, and a stick-slip principle is analyzed. The two motion control methods are validated by both simulations and prototype experiments.