Many types of common objects, such as tools and vehicles, usually move in simple ways when they are wielded or driven: The natural axes of the object tend to remain aligned with the local trihedron defined by the object's trajectory. Based on this observation we use a model called Frenet-Serret motion which corresponds to the motion of a moving trihedron along a space curve. Knowing how the Fre...

The problem of optimal grasping of an object by a multifingered robot hand is discussed. Using screw theory and elementary differential geometry, the concept of a grasp is axiomated and its stability characterized. Three quality measures for evaluating a grasp are then proposed. The last quality measure is task oriented and needs the development of a procedure for modeling tasks as ellipsoids i...

A T-handle has been designed to be used for minimally invasive implantation of a dynamic hip screw to repair fractures of the proximal femur. It is capable of being used in two actions: (i) push and hold (while using an angle guide) and (ii) application of torque when using the insertion wrench and lag screw tap. The T-handle can be held in a power or precision grip. It is suitable for either s...

Address for correspondence: Dr. Ankur Khandelwal, Department of Anaesthesiology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Rae Barelly Road, Lucknow ‐ 226 014, Uttar Pradesh, India. E‐mail: [email protected] Sir, Securing of any external devices such as endotracheal tube (ETT), tracheostomy tube (TT), arterial and central venous catheters, nasogastric tubes, drainage tubes...

The quality of a grasp can often be measured as the magnitude within which any external wrench is resistible by \unit grasp force". In this paper, we present a numerical algorithm to compute the optimal grasp on a simple polygon, given contact forces of unit total magnitude. Forces are compared with torques over the radius of gyration of the polygon. We also address a grasp optimality criterion...

In this paper, a control solution featuring an energetic constraint is developed to improve the safety of a robotic manipulator sharing its workspace with humans. This general control structure, exploits a generic safe controller that ensures the respect of multiple constraints thanks to a Linear Quadratic Problem formulation. With a unified energetic formulation, the controller allows to expli...

In this paper we propose a force position control scheme in a DOF task space which is a generalization of the parallel control scheme in a DOF task space The con troller consists of a PD action on the position loop a PI action on the force loop together with gravity com pensation and feedforward of the desired contact force Kinestatic ltering is not used in the scheme Euler pa rameters are adop...

There are several examples of heuristic rules first proposed from empirical observation, which eventually earned physicochemical validity after the fundamental derivation of a posteriori. This may be the case of Sherwood’s plot – for which a sound rationalization from first principles, entailing enthalpy and mass balances, is provided here; it applies to (fine) chemicals undergoing concentr...