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%.