We consider a variational inequality for the Lamé system which models an elastic body in contact with a rigid foundation. We give conditions on the domain and the contact set which allow us to prove regularity of solutions to the variational inequality. In particular, we show that the gradient of the solution is a square integrable function on the boundary.

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...

Tensegrity frameworks are defined on a set of points in Rd and consist of bars, cables, and struts, which provide upper and/or lower bounds for the distance between their endpoints. The graph of the framework, in which edges are labeled as bars, cables, and struts, is called a tensegrity graph. It is said to be strongly rigid in Rd if every generic realization in Rd as a tensegrity framework is...

The 2 most common complications of reduction malarplasty are nonunion or malunion and cheek drooping. Because masseter muscle is attached from zygomatic process of the maxilla to inferior two thirds of the zygomatic arch, rigid fixation and intimate bone contact without creating a gap are crucial for reduction malarplasty.Mesial-clockwise rotation of the zygomaticomaxillary complex can produce ...

A direction-length framework is a pair (G, p), where G = (V ;D,L) is a ‘mixed’ graph whose edges are labeled as ‘direction’ or ‘length’ edges, and p is a map from V to R for some d. The label of an edge uv represents a direction or length constraint between p(u) and p(v). Let G be obtained from G by adding, for each length edge e of G, a direction edge with the same end vertices as e. We show t...

Adhesive forces are capable of deforming a soft elastic object when it comes in contact with a flat rigid substrate. The contact is in stable equilibrium if the total energy of the system arising from the elastic and surface forces exhibits a minimum at a zero or at a slightly negative load. However, as the system is continually unloaded, the energy barrier decreases and it eventually disappear...

OBJECTIVE To present success of Toris-K contact lenses in keratoconus and traumatic keratopathy with irregular corneal surface. METHODS Toris-K contact lenses were used to treat 7 eyes of 4 patients with traumatic keratopathy (Case 1) or keratoconus (Case 2, Case 3, and Case 4). All cases had a complete eye examination before the contact lens application. The case with traumatic keratopathy w...

This paper describes the contact formation modeling for the identification of geometrical parameters (positions, orientations and dimensions) of rigid polyhedral objects in contact during the force-controlled execution of contact formation sequences. Following improvements with respect to the state of the art are made: (i) the modeling effort is reduced considerably, (ii) the generation of the ...

We consider the problem of impedance control for the physical interaction between the soft tip of a robot finger, where the nonlinear characteristics of the reproducing force and the finger dynamic parameters are unknown, and a rigid object or environment under kinematic uncertainties arising from both uncertain contact point location and uncertain rigid object geometry. An adaptive controller ...

This paper deals with the handling of deformable linear objects (DLOs), such as hoses, wires, or leaf springs. It investigates usable features for the visionbased detection of a changing contact situation between a DLO and a rigid polyhedral obstacle and a classification of such contact state transitions. The result is a complete classification of contact state transitions and of the most signi...