Modeling of a Hexapod Robot; Kinematic Equivalence to a Unicycle

Abstract

This report describes the kinematic and dynamic modeling of a hexapod robot. The 6-DOF (degrees of freedom) analytical kinematic and dynamic equations of motion are derived following the classical Newtonian mechanics. Under certain task-specific assumption, it is shown that the complex 6-DOF model can be simplified, resulting in an abstract model. Specifically, the motion of the robot on the horizontal plane in particular is described by the unicycle model with dynamic extension. The abstract unicycle model exhibits restricted behavior compared to the concrete hexapod model, but facilitates motion planning and control design and ensures that higher level control plans are implementable as low level control laws.