In this paper, in order to perform delicate and advanced grip control like human, a proximity and tactile combination sensor using miniaturized microcantilevers one-fifth the size of previous one as the detection part was newly developed. Microcantilevers were arranged with higher spatial density than in previous works and an interdigitated array electrode to enhance light sensitivity was added. It is found that the interdigitated array electrode can detect light with 1.6 times higher sensitivity than that in previous works and the newly fabricated microcantilevers have enough sensitivity to applied normal and shear loads. Therefore, more accurate detection of proximity distance and spatial distribution of contact force become available for dexterous gripping control to prevent ‘overshooting’, ‘force control error’, and ‘slipping’.
Tactile array sensor of the micro-cantilevers embedded in the elastomer has been fabricated to detect normal and 2-axes shear stresses. It is demonstrated that tactile array sensor with 3 times 3 detective elements can be fabricated with excellent yield. The sensor element is sensitive to both normal and shear stresses applied on entire sensor surface. Moreover, it has good directional characteristics so that it is shown that magnitude and direction of shear stress can be obtained by difference of output voltages of adjacent sensor cantilevers. The sensor output has good reproducibility for multiple measurement. The output from sensor element drastically changes with shifting applying position of force. It is considered that we can obtain pressed position from distribution of output from sensor element array.