We build on previous works advocating the use of the Gravito-Inertial Wrench Cone (GIWC) as a general contact stability criterion (a “ZMP for non-coplanar contacts”). We show how to compute this wrench cone from the friction cones of contact forces by using an intermediate representation, the surface contact wrench cone, which is the minimal representation of contact stability for each surface ...

In lathe operation, the most frequently used wrenches are chuck and tool holder wrenches, which different in structure function cannot be replaced, forgetting to remove will cause safety accidents. To solve above problems, this paper designs a new type of wrench, integrates functions wrench various screwdrivers, can easily change form by certain improves production efficiency eliminates hazards.

An ensemble of screws is known as a screw system, and is deened by a set of n 6 independent basis screws. The order of a screw system is equal to the number of basis screws required to deene it; such a system is also called an n-system. The order of a screw system reciprocal to an n-system is (6 ? n). With an innnitesimal rigid motion of an object in three-dimensional Euclidean space there is a...

space 1 The space of twist Joint space The space of wrench (6) jT T T J ~ ( = J KI Ii) I ' * 1 v torque space 1 Figure 2.6: Transformation from Task Domain to Joint Domain where each column of J is the image in abstract space of the corresponding column of the Jacobian J . Thus. the base of the joint variable space is: and the base of the joint torque space is: Because J is a matrix defined in ...

introduction: the purpose of this study was to compare the accuracy of the torque wrenches used in different dental implant systems. methods: we evaluated 42 torque wrenches used in different dental clinics in mashhad, iran, using a digital torque meter (mark 10). high (25, 30 and 35 n·cm) and low (15 n·cm) levels of torque were examined. ten tests were performed on each wrench, and the mean va...

We present a framework to enable a fleet of rigidly attached quadrotor aerial robots to transport heavy objects along a known reference trajectory without interrobot communication or centralized coordination. Leveraging a distributed wrench controller, we provide exponential stability guarantees for the entire assembly, under a mild geometric condition. This is achieved by each quadrotor indepe...

This research focuses on improved force-reflecting teleoperation system control in free motion and contact tasks. Specifically, the Naturally-Transitioning Rate-to-Force Controller (NTRFC) is implemented in an Air Force experimental force-reflecting teleoperation system to: 1) achieve a unified controller with no mode switches from free motion to contact; and 2) reduce the wrench exerted on the...

The wrench-closure workspace of parallel cable-driven mechanisms is the set of poses for which any wrench can be produced at the end-effector by a set of a non-negative cable tensions. It is already known that the boundary of the constant-orientation wrench-closure workspace of a planar parallel cable-driven mechanism is composed of segments of conic sections. Howevel; the relationship between ...

The paper deals with the problem of finding a form-closure fixturing of objects modeled with triangular meshes and considering as quality measure the maximum wrench that the object can resist in any direction. Although a triangular mesh is a polyhedral representation of the object, the number of faces is too large to allow a practical application of existing approaches for polyhedral objects, a...