Integration of Active Control and Passive Compliance for Peg-and-hole Assembly

This thesis provides a brief intro to the peg-and-hole problem and goes through two active and passive compliance strategies as well as the cases that the compliance center position is not ideal. A specific scenario of peg being gripped at an error angle due to large vision uncertainties is raised and studied. Such setup can lead to an off compliance center position relative to the peg and can happen in real life but has not been solved by previous approaches. A potential solution to it by combining active control and passive compliance is provided and analyzed. By using the force and torque feedback and the robot joint angle information, the compliance center for the above scenario could be estimated without vision feedback to by-pass the potential accuracy limitation of vision sensors. And a position control with reference determined in real-time by these sensors would be able to cancel out the majority of the effect caused by an off compliance center. Additional recommendations to future work on integration of active and passive compliance strategies and utilization of arbitrary compliance center positions are provided as well.