Passivity-based Cascade Hybrid Pose/Force Robot Control

This work presents an adaptation of the Time-Domain Passivity Approach (TDPA) to enhance robustness of a cascade hybrid control scheme for interaction between a robotic manipulator and an unknown surface. A cascade control is proposed to combine a task space kinematic hybrid position/force and orientation control law in the outer loop and a joint space inverse dynamics control law in the inner loop. The proposed kinematic TDPA acts on the force control part of the hybrid scheme to ensure passivity and contact stability even in the presence of unmodeled features in the force sensor attached to the end-effector and in the control channel. Simulations and experimental results are presented to show the efficacy of the proposed method when significant force measurement delay and surface stiffness variation are introduced.