John E. Lloyd

Bio: John E. Lloyd is an academic researcher from University of British Columbia. The author has contributed to research in topics: Robot control & Gravitational singularity. The author has an hindex of 22, co-authored 71 publications receiving 1657 citations. Previous affiliations of John E. Lloyd include Katholieke Universiteit Leuven & McGill University.

Scanning physical interaction behavior of 3D objects

Abstract: We describe a system for constructing computer models of several aspects of physical interaction behavior, by scanning the response of real objects. The behaviors we can successfully scan and model include deformation response, contact textures for interaction with force-feedback, and contact sounds. The system we describe uses a highly automated robotic facility that can scan behavior models of whole objects. We provide a comprehensive view of the modeling process, including selection of model structure, measurement, estimation, and rendering at interactive rates. The results are demonstrated with two examples: a soft stuffed toy which has significant deformation behavior, and a hard clay pot which has significant contact textures and sounds. The results described here make it possible to quickly construct physical interaction models of objects for applications in games, animation, and e-commerce.

ArtiSynth: A Fast Interactive Biomechanical Modeling Toolkit Combining Multibody and Finite Element Simulation

Abstract: ArtiSynth (http://www.artisynth.org) is an open source, Java-based biomechanical simulation environment for modeling complex anatomical systems composed of both rigid and deformable structures. Models can be built from a rich set of components, including particles, rigid bodies, finite elements with both linear and nonlinear materials, point-to-point muscles, and various bilateral and unilateral constraints including contact. A state-of-the-art physics simulator provides forward simulation capabilities that combine multibody and finite element models. Inverse simulation capabilities allow the computation of the muscle activations needed to achieve prescribed target motions. ArtiSynth is highly interactive, with component parameters and state variables exposed as properties that can be interactively read and adjusted as the simulation proceeds. Streams of input and output data, used for controlling or observing the simulation, can be viewed, arranged, and edited on an interactive timeline display, and support is provided for the graphical editing of model structures.

Coupled hard―soft tissue simulation with contact and constraints applied to jaw―tongue―hyoid dynamics

Abstract: We present an open-source physical simulation system suitable for efficient modeling of anatomical structures composed of both hard and soft tissue components, interconnected by point-wise attachments, contact, and other constraints. Specific attention is paid to the computational formulation needed for the coupled simulation of rigid and deformable structures, and a constraint-based mechanism is described for attaching these together. As an application of this system, we then present a novel 3D dynamic model of the jaw-tongue-hyoid complex, consisting of an FEM model of the tongue, rigid jaw, and hyoid structures, point-to-point muscle actuators, and constraints for bite contact and the temporomandibular joints. Several simulations are presented showing combined jaw-tongue actions and demonstrating the effects of coupled jaw-tongue-hyoid dynamics.

The C programming language

Abstract: This ebook is the first authorized digital version of Kernighan and Ritchie's 1988 classic, The C Programming Language (2nd Ed.). One of the best-selling programming books published in the last fifty years, "K&R" has been called everything from the "bible" to "a landmark in computer science" and it has influenced generations of programmers. Available now for all leading ebook platforms, this concise and beautifully written text is a "must-have" reference for every serious programmers digital library. As modestly described by the authors in the Preface to the First Edition, this "is not an introductory programming manual; it assumes some familiarity with basic programming concepts like variables, assignment statements, loops, and functions. Nonetheless, a novice programmer should be able to read along and pick up the language, although access to a more knowledgeable colleague will help."

Robot Manipulator Control: Theory and Practice

Abstract: Robot Manipulator Control offers a complete survey of control systems for serial-link robot arms and acknowledges how robotic device performance hinges upon a well-developed control system. Containing over 750 essential equations, this thoroughly up-to-date Second Edition, the book explicates theoretical and mathematical requisites for controls design and summarizes current techniques in computer simulation and implementation of controllers. It also addresses procedures and issues in computed-torque, robust, adaptive, neural network, and force control. New chapters relay practical information on commercial robot manipulators and devices and cutting-edge methods in neural network control.

Force feedback and texture simulating interface device

Abstract: A man-machine interface is disclosed which provides force and texture information to sensing body parts. The interface is comprised of a force actuating device that produces a force which is transmitted to a force applying device. The force applying device applies the generated force to a pressure sensing body part. A force sensor on the force applying device measures the actual force applied to the pressure sensing body part, while angle sensors measure the angles of relevant joint body parts. A computing device uses the joint body part position information to determine a desired force value to be applied to the pressure sensing body part. The computing device combines the joint body part position information with the force sensor information to calculate the force command which is sent to the force actuating device. In this manner, the computing device may control the actual force applied to a pressure sensing body part to a desired force which depends upon the positions of related joint body parts. In addition, the interface is comprised of a displacement actuating device which produces a displacement which is transmitted to a displacement applying device (e.g., a texture simulator). The displacement applying device applies the generated displacement to a pressure sensing body part. The force applying device and displacement applying device may be combined to simultaneously provide force and displacement information to a pressure sensing body part.