Showing papers by "Michael A. Peshkin published in 1998"

Cobots: a novel material handling technology

Abstract: Cobots are a class of hybrid human-controlled/computercontrolled material handling device, which can enhance ergonomics, productivity, and safety. Cobots implement software-defined virtual guiding surfaces, as well as providing some amplification of human power ("power assist"). Cobots make use of steerable nonholonomic joints to produce the guiding surfaces that aid the operator. This unique steering system, in place of powerful actuators, results in guiding surfaces that are smooth, frictionless, and intrinsically stable -making cobots particularly appropriate for safety-critical tasks. In this paper we describe the basic concepts of cobots with reference to laboratory prototypes having two or three workspace dimensions. Early industrial application in automobile final assembly plants is underway, and two cobots presently in industrial environments are described

Long-range geometrical correlations in two-dimensional foams

Abstract: The statistical properties of two-dimensional, space-filling random cellular structures (foams, or their dual, random triangulations) in statistical equilibrium are obtained by maximum entropy inference and topological simulations. We show by maximum entropy inference that for a broad class of foams (shell-structured, including three-sided cell inclusions), all two-cell topological correlators Aj.k;n/ (average number of pairs of k-cell and n-cell at a topological distance j ) are linear in n and k, the numbers of neighbours of the cells. This generalizes a correlation known for neighbouring cells (j D 1) which implies the linearity of Aboav's relation (between the total number of neighbours of the cells adjacent to a n-neighboured cell andn). Our results, verified by simulations, also build up Gauss's theorem for cellular structures. Any additional restriction in exploring local cell configurations, besides the constraints of filling space at random, will manifest itself through a deviation from linearity of the correlators Aj.k;n/ and the Aboav relation. Notably, foams made of Feynman diagrams have additional, context- dependent restrictions and their Aboav relation is slightly curved. It is essential that the local random variablen denotes the number of neighbours of the cell and not that of its sides, whenever the two are different.

Non-holonomic user interface for a robot

Abstract: An apparatus and method for direct physical interaction between a person and a general purpose manipulator (10) controlled by a computer. The appartus, known as a collaborative robot or 'cobot' (10), may take a number of configurations common to conventional robots. In place of the actuators that move conventional robots, however, cobots use variable transmission elements (20) whose transmission ratio is adjustable under computer control via small servomotors (50). Cobots (10) thus need few if any powerful, potentially dangerous, actuators. Instead, cobots (10) guide, redirect, or steer motions that originate with the person. A method is also disclosed for using the cobot's (10) ability to redirect and steer motion in order to provide physical guidance for the person, and for any payload being moved by the person and the cobot (10). Virtual surfaces, virtual potential fields, and other guidance schemes may be defined in software and brought into physical effect by the cobot (10).

Cobots: a novel material handling technology

Abstract: Cobots are a class of hybrid human-controlled/computercontrolled material handling device, which can enhance ergonomics, productivity, and safety. Cobots implement software-defined virtual guiding surfaces, as well as providing some amplification of human power ("power assist"). Cobots make use of steerable nonholonomic joints to produce the guiding surfaces that aid the operator. This unique steering system, in place of powerful actuators, results in guiding surfaces that are smooth, frictionless, and intrinsically stable -making cobots particularly appropriate for safety-critical tasks. In this paper we describe the basic concepts of cobots with reference to laboratory prototypes having two or three workspace dimensions. Early industrial application in automobile final assembly plants is underway, and two cobots presently in industrial environments are described

Synergistic mechanical devices: a new generation of medical robots

Abstract: There are many roles for electromechanical devices in image guided surgery. One is to help a surgeon accurately follow a preoperative plan. Devices for this purpose may be localizers, robots1, or recently, synergistic systems in which surgeon and mechanism physically share control of the surgical tool. This paper discusses available technologies, and some emerging technologies, for guiding a surgical tool. Characteristics of each technology are discussed, and related to the needs which arise in surgical procedures. Three different approaches to synergistic systems, under study by the authors (PADyC, ACROBOT, and Cobots), are highlighted.