Robotic contour tracking with force control and an operational space disturbance observer

Robots in the industry are used for operations that are particularly dangerous or challenging to complete with high efficiency and precision for humans. These robots require extensive programming to achieve high level tasks and reprogramming to repeat the task in different environmental conditions. Introducing some level of autonomy for the robots is desired to decrease the burden on the programmer by enabling the robot to adapt to environmental changes and accomplish the required tasks with minimal human interaction. Contour tracking is a task that can be completed autonomously by a robot and assist in the completion of several industrial operations in the process such as grinding, deburring, polishing and shape recovery. Hybrid control is a popular method for achieving contour tracking. This thesis presents a hybrid controller that employs feedforward and integral force actions in the contact normal direction; and dynamics based proportional velocity control with disturbance estimation in the tangent direction. The effectiveness of the presented method has been validated and its superiority compared to conventional PI velocity control is proven experimentally. A simple and reliable method for contact estimation is also presented