Dynamics and Control of Robotic Manipulators with Contact and Friction

3Friction and Contact of Solid Interfaces

3.1 Introduction

Friction is resistant force in moving interface of a dynamical system. To quantify friction, surface roughness that possesses statistical properties should be characterized. Friction is concerned with surface topography, and therefore the determination of the real area of contact and the understanding of the mechanism of mating contacts are critical to characterize friction [1–11]. Particularly, the surface physics can help elaborate the friction in terms of the formation of adhesive junctions by interacting asperities and their breakaway by shearing, whereas continuum mechanics quantify friction by interlock and fracture of asperities [12–14].

To address the problem of real sliding asperity contact is quite difficult, which involves in complex dynamics. The feasible approach is to assume the contact to be of a quasi‐static nature to certain extent. In many applications with relatively smooth surfaces the deformation of contacting asperities can be assumed to be linear and elastic. For many problems, the contact has to be extended to inelastic and nonlinear conditions and to involve in dynamics [15–25].

In this chapter we present the fundamentals of contact and friction between two contact surfaces in the context of quasi‐static state by assuming that the normal motion is ignored. We focus on the mechanics of contact and friction by outlining the mechanical attributes of various friction processes in the context of the ...