Towards approximate models of coulomb frictional moments in: I) revolute pin joints and II) spherical-socket ball joints (original) (raw)

In general, the rigid-contact assumption has been used to estimate the frictional moment between two bodies in contact. In a multi-body connection, two types of passive interconnection are considered in this paper, namely pin joint and spherical-ball joint. The joints are assumed to be passive at the localized configuration space of the multi-body systems and are assumed to be actuated remotely. The traditional approach for modelling such frictional contact does not consider the elastic deformation of joints. Two approximate models are presented for both revolute pin joints and spherical-socket ball joints. The proposed models offer a more accurate estimation of the Coulomb frictional moment. The new models offer a compact solution which can be easily extended to other geometrical multi-body contact configuration with various degrees of clearance. The proposed models can be used in the dynamic modelling and control of multi-body systems in frictional contact.