Modeling and control of multiple-contact manipulation without modeling friction

Multiple contact manipulation often involves contacts that slip or lose contact over time. This slipping introduces frictional reaction forces between the manipulator and the surface. However, in complex systems in uncertain environments, these frictional interactions may not be well-characterized. This paper discusses the reduction of such external forces in multiple contact systems. We then present two examples: a macro-scale multi-point manipulator and MEMS scratch drive actuators (SDA) array to illustrate how the techniques presented can simplify the control design for such devices