Shape design optimization of interdigitated electrodes for maximal electro-adhesion forces

We present a shape design optimization method for interdigitated electrodes in an electro-adhesive device. In the finite element analysis of electrostatics using linear basis functions, a finite node displacement method is used for the accurate electro-adhesive force by integrating the electric field along the boundary surface. The floating potential boundary for conductive objects is handled by a charge conservation law in the electrostatic analysis as well as the shape design sensitivity analysis. In numerical examples, the structural shape of interdigitated electrodes is optimized to maximize the electro-adhesion force per unit area for both conductive and non-conductive objects. It turns out that the electro-adhesive force is mainly induced by an electrostatic induction for conductive objects and by an electric polarization for non-conductive ones. There is an optimal ratio of electrode width and air gap thickness for non-conductive objects but no limit for conductive objects.