Environment Exploration for Impedance Control Based Manipulators: Initial Experimental Study on Object Position Detection with Stable Contact

Robotic manipulation under unstructured environments still is an open challenge to the research community. Lots of effort have been addressed to visual perception and remarkable progress has been achieved in the area. However, the information obtained from vision systems is frequently incomplete and noisy, incapacitating robotic systems to complete their target tasks in some cases. Moreover, little attention has been given to the use of exploration by touch as an approach to enrich environment perception, mainly due to difficulties that arrive from stable physical interaction with the environment. This work presents the experimental results from an initial study on the capability of an impedance controlled manipulator perceiving its surrounding environment using touch as source of information. The experiments culminate on a repeatability test which indicates that such a method provides higher precision information in comparison with 3D vision systems. The experimental procedures consider different impedance parameters during establishment and loss of contact. Considering the obtained results, different surface approach heuristic are evaluated to determine the most appropriated to, firstly, establish a stable contact with the environment and secondly, as a consequence, to perform spatial measures.