Constrained robot motion in presence of stiff and compliant contact

The problem of simultaneous position and force control for robots moving in contact with the environment is typically formulated under the assumption of infinitely stiff interaction. A rigorous approach is presented to formulate and solve the control problem under both stiff and compliant assumptions. A suitable formalism is first developed for the description of robot-environment stiff and compliant interactions. The model structure obtained is helpful for the design of control schemes of various complexity and for the construction of stability proofs. Two kinds of control laws are derived, denoted as dynamic and kinematic, respectively. Dynamic control laws fully exploit the robot-environment kinematic and dynamic models, while kinematic laws use the kinematic description of robot dynamics