| The capability of performing constrained motion tasks is key to many robotic applications that involve material handling, milling, deburring, polishing and surface tracking. Many strategies for performing constrained motion control have been proposed. The major drawback of these strategies is that they do not provide for the manipulator to interact with poorly structured or unknown environments. This is because using these strategies the interaction forces between the end-effector and the workpiece cannot be controlled in arbitrary directions.; This thesis presents the design of a new controller implemented in the robot tool space that can control the interaction forces in arbitrary directions. Using the proposed controller, the manipulator can interact with workpieces whose shapes are not pre-specified. Thus tasks like milling, deburring and polishing, that involve constrained motion control of the manipulator can be performed on a wide variety of workpieces without explicit knowledge of the shape of the workpiece. The design and proof of stability for this tool space hybrid force/position controller is presented. A comparison of this new tool space hybrid force/position controller with the existing task space hybrid force/position controller is also presented. Simulations studies for the task of tracking unknown surfaces are also presented. |
