The effect of self-affine roughness on the actuation of a micromechanical system (MEMS) under the influence of the lateral Casimir force is investigated. For a conservative system, both bifurcation curve and phase portrait analysis show that when the surface of components is extremely rough, reducing the roughness leads to a wider stable operation area under small lateral displacements. Smoother rough surfaces exhibit the opposite behavior. Large lateral displacements reduce the stable area as roughness increases. In non-conservative systems, the Melnikov method reveals that a significant increase in roughness leads to a substantial reduction in the stable area, causing chaotic motion in MEMS with sever rough surfaces. On the other hand, reducing roughness on smooth surfaces can lead to chaotic motion.
F. Tajik (Wed,) studied this question.