Hybrid Force-Impedance Control for Fast End-Effector Motions

Controlling the contact force on various surfaces is essential in many robotic applications such as in service tasks or industrial use cases. Mostly, classical impedance and hybrid motion-force control approaches are employed for these kinds of physical interaction scenarios. In this work, an extended Cartesian impedance control algorithm is developed, which includes geometrical constraints and enables explicit force tracking in a hybrid manner. The unified framework features compliant behavior in the free (motion) task directions and explicit force tracking in the constrained directions. Advantageously, the involved force subspace in contact direction is fully dynamically decoupled from dynamics in the motion subspace. The experimental validation with a torque-controlled robotic manipulator on both flat and curved surfaces demonstrates the performance during highly dynamic desired trajectories and confirms the theoretical claims of the approach.