Force control without inverse kinematics nor robot model

When a robot manipulator has to interact with its environment, it is desirable to control the force exerted by the end-effector. There are many well-know algorithms to achieve this goal, both in Cartesian and joint coordinates. In the first case, the robot model is more complex, while in the second one inverse kinematics is to be employed, since the task is usually given in workspace coordinates. In this paper, we propose a force algorithm which does not need neither the computation of inverse kinematics nor the knowledge of the robot model. Furthermore, joint velocities are not used. Experimental results are provided to test the developed theory.