Simultaneous Contact Point and Surface Normal Estimation during Soft Finger Contact

This paper presents a method for online estimation of contact point and surface normal from in-contact motion of a robot manipulator equipped with a force/torque sensor. Two interconnected linear estimators are used to solve the estimation problem. The estimation applies to contacts that can be modeled with the soft finger contact model, which is a generalization of previous work. We present a condition under which the two estimated parameters (surface normal and contact point) converge to their true values. The proposed estimation algorithm is verified in simulation and validated on a collaborative robot manipulator