Accurately modeling contact behaviors for realworld, near-rigid materials remains a grand challenge for existing rigid-body physics simulators. This paper introduces a data-augmented contact model that incorporates analytical solutions with observed data to predict the contact impulse between a particular pair of objects (e.g. a specific robot foot contacting a specific surface). The method enh...

Three adult rhesus monkeys were subjected to 2 and 24 hours of polymethylmethacrylate (PMMA) contact lens wear. The induced corneal changes were examined with the electron microscope. Mild epithelial oedema as well as early degenerative cell changes was present already after 2 hours' wear. Rigid lens wear for 24 hours produced more severe oedema and cell alterations together with premature cell...

We present a new approach to modeling contact between rigid objects that augments an individual Coulomb friction point-contact model with rolling and spinning friction constraints. Starting from the intersection volume, we compute a contact normal from the volume gradient. We compute a contact position from the first moment of the intersection volume, and approximate the extent of the contact p...

Previous work in rigid body dynamic simulation has relied on rigid body impact models to model collisions. The well-known models due to Newton, Poisson, and Brach, are each based on a deenition of a coeecient of restitution for rigid body impact. The objective of this paper is to develop a new model that overcomes the deeciencies of these models in frictional impacts and to present a formulatio...

The use of rigid body models during frictional contact i s often justified by proving the existence of a unique solution to the forward dynamic equations. The implicit assumption here is that the contact forces so obtained are stable. In this paper, the rigid-body assumption is relaxed and bodyto-body contacts are modeled using springs and dampers. A singular perturbation analysis reveals addit...

Inverse dynamics is used extensively in robotics and biomechanics applications. In manipulator and legged robots, it can form the basis of an effective nonlinear control strategy by providing a robot with both accurate positional tracking and active compliance. In biomechanics applications, inverse dynamics control can approximately determine the net torques applied at anatomical joints that co...

This article presents computationally efficient algorithms for modeling two special cases of rigid contact— contact with only viscous friction and contact without slip—that have particularly useful applications in robotic locomotion and grasping. Modeling rigid contact with Coulomb friction generally exhibits O(n) expected time complexity in the number of contact points and 2 worst-case complex...

BACKGROUND Visual outcome following repair of post-traumatic corneal perforation may not be optimal due to presence of irregular keratometric astigmatism. We performed a study to evaluate and compare rigid gas permeable contact lens and spectacles in visual rehabilitation following perforating corneal injuries. METHOD Eyes that had undergone repair for corneal perforating injuries with or wit...