Optimization of a thermal slip sensor using FEM and dimensional analysis

During manipulation tasks it is important to maintain a precise and safe control of the grasping force. Slip detection plays a key role to assure an adequate adaptation of the grasping force, without object damaging. Several approaches to slip detection are currently under investigation. In particular, thermal slip sensors use a detection strategy similar to the one employed in hot wire anemometry, using a microfabricated thermal probe for detecting the convective heat flux associated to the movement of the touched object. This paper reports on the model-based optimization of a thermal slip sensor, intended for robotic prosthesis. In particular, an analytical thermal model has been developed, by merging FEM and dimensional analysis. A sensitivity analysis, performed on the parameters appearing in the model, has been performed for optimizing both sensor´s geometry and materials in order to increase the heat flux and thereby to obtain a reduction of response times in the identification of slip. Simulations on the proposed design indicate an expected increase of the thermal dissipated power of about 400%.