Hybrid Force Motion Synchronization Control of Robot Manipulators

Abstract

The main objective of this thesis was to combine the theory on synchronization of robot manipulators with the concept of hybrid force/motion control; resulting in a controller capable of following both the trajectory of another robot and a desired force trajectory at the same time. This report includes a short introduction to synchronization theory for robot manipulators, and a more thorough summary of existing hybrid control schemes. An intuitive method for describing constraints caused by the environment is presented, and this leads to a straightforward way to separate the interaction control problem into two subproblems. When the manipulator end-effector is in contact with a surface, the hybrid controller tracks a position reference along the surface and a force reference normal to the surface. The contribution of this thesis is a proposed hybrid controller, incorporating ideas from previous hybrid schemes. The closed loop system is shown to be globally asymptotically stable in the position controlled degrees of freedom, and bounded in the force controlled degrees of freedom. The performance of the proposed hybrid control concept is demonstrated by simulations. The proposed hybrid controller easily reduces to a pure position controller when desired.