multicontact

Multicontact refers to a situation in which multiple discrete contact points occur between two or more bodies during interaction. This contrasts with single-contact models and introduces additional degrees of freedom for the distribution of contact forces. In multicontact settings, contact forces arise at several locations, and the overall interaction depends on the collective behavior of all contact points, including transitions between sticking and sliding due to friction.

In mechanics and robotics, multicontact is often analyzed using contact mechanics with friction. Each contact point is described by a normal force and a tangential force that must satisfy frictional constraints, typically modeled by Coulomb friction. The set of admissible tangential forces forms a friction cone around the normal direction, and contact can switch between sticking (zero relative motion) and sliding (relative motion along the boundary of the cone). The overall system is governed by complementarity or variational inequality formulations, and solutions may be time-dependent as contacts engage or disengage.

Applications of multicontact theory include robotic manipulation with multi-finger grippers, where stable object handling depends on force distribution across contacts; legged locomotion and manipulation in rough environments; haptic devices; and industrial assembly tasks. Challenges in multicontact modeling include force distribution indeterminacy in rigid-body assumptions, the complexity of contact switching, nonlinearity of friction, and the need for accurate geometric models. Researchers address these through compliant or reduced-order models, regularization techniques, and numerical methods for multi-contact dynamics.