This paper presents a numerically robust algorithm for solving linear complementarity problems (LCPs), and applies it to simulation of frictional contacts of articulated rigid bodies each modeled as a general polygonal object. We first point out two problems of the popular pivot-based LCP solver called Lemke Algorithm and its extension with lexicographic ordering, due to numerical errors especi...

We investigated the coordination of fingertip forces in subjects who used the tips of two fingers to restrain an instrumented manipulandum with horizontally oriented grip surfaces. The grip surfaces were subjected to tangential pulling forces in the distal direction in relation to the fingers. The subjects used either the right index and middle fingers (unimanual grasp) or both index fingers (b...

Beginning with a proof of the existence of a discrete-time trajectory, this paper establishes the convergence of a time-stepping method for solving continuous-time, boundary-value problems for dynamic systems with frictional contacts characterized by local compliance in the normal and tangential directions. Our investigation complements the analysis of the initial-value rigid-body model with on...

We present a formulation of rigid body dynamics with frictional contact that leverages ideas from discrete mechanics to derive time-stepping schemes with any desired order of integration accuracy. By utilizing the new time-stepping methods as dynamics constraints in a direct trajectory optimization scheme, we are able to perform contact-implicit trajectory optimization with accuracy equal to tr...

The increasing development of smart materials, such as piezoelectric and shape memory alloys, has opened new opportunities for improving repair techniques. Particularly, active repairs, based on the converse piezoelectric effect, can increase the life of a structure by reducing the crack opening. A deep characterization of the electromechanical behavior of delaminated composite structures, acti...

Scanning force microscopy (SFM) is used to investigate novel perturbation/response phenomena in a soft polymer network. Topics addressed include (i) the volume of film affected by tip-sample contact and (ii) the time-evolving residual signature of this contact. An outward deformation of nanometer-scale, soft, hydrated gelatin films is induced by the close proximity of the SFM tip. A domelike de...