4,788 research outputs found

    Virtual intimacy: Phya as an instrument

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    Phya is an open source C++ library originally designed for adding physically modeled contact sounds into computer game environments equipped with physics engines. We review some aspects of this system, and also consider it from the purely aesthetic perspective of musical expression

    Architecture independent environment for developing engineering software on MIMD computers

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    Engineers are constantly faced with solving problems of increasing complexity and detail. Multiple Instruction stream Multiple Data stream (MIMD) computers have been developed to overcome the performance limitations of serial computers. The hardware architectures of MIMD computers vary considerably and are much more sophisticated than serial computers. Developing large scale software for a variety of MIMD computers is difficult and expensive. There is a need to provide tools that facilitate programming these machines. First, the issues that must be considered to develop those tools are examined. The two main areas of concern were architecture independence and data management. Architecture independent software facilitates software portability and improves the longevity and utility of the software product. It provides some form of insurance for the investment of time and effort that goes into developing the software. The management of data is a crucial aspect of solving large engineering problems. It must be considered in light of the new hardware organizations that are available. Second, the functional design and implementation of a software environment that facilitates developing architecture independent software for large engineering applications are described. The topics of discussion include: a description of the model that supports the development of architecture independent software; identifying and exploiting concurrency within the application program; data coherence; engineering data base and memory management

    Dance Teaching by a Robot: Combining Cognitive and Physical Human-Robot Interaction for Supporting the Skill Learning Process

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    This letter presents a physical human-robot interaction scenario in which a robot guides and performs the role of a teacher within a defined dance training framework. A combined cognitive and physical feedback of performance is proposed for assisting the skill learning process. Direct contact cooperation has been designed through an adaptive impedance-based controller that adjusts according to the partner's performance in the task. In measuring performance, a scoring system has been designed using the concept of progressive teaching (PT). The system adjusts the difficulty based on the user's number of practices and performance history. Using the proposed method and a baseline constant controller, comparative experiments have shown that the PT presents better performance in the initial stage of skill learning. An analysis of the subjects' perception of comfort, peace of mind, and robot performance have shown a significant difference at the p < .01 level, favoring the PT algorithm.Comment: Presented at IEEE International Conference on Robotics and Automation ICRA-201

    Evaluation of automated decisionmaking methodologies and development of an integrated robotic system simulation, appendix A

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    A generic computer simulation for manipulator systems (ROBSIM) was implemented and the specific technologies necessary to increase the role of automation in various missions were developed. The specific items developed were: (1) Capability for definition of a manipulator system consisting of multiple arms, load objects, and an environment; (2) Capability for kinematic analysis, requirements analysis, and response simulation of manipulator motion; (3) Postprocessing options such as graphic replay of simulated motion and manipulator parameter plotting; (4) Investigation and simulation of various control methods including manual force/torque and active compliance control; (5) Evaluation and implementation of three obstacle avoidance methods; (6) Video simulation and edge detection; and (7) Software simulation validation. This appendix is the user's guide and includes examples of program runs and outputs as well as instructions for program use

    Evaluation of automated decisionmaking methodologies and development of an integrated robotic system simulation. Appendix A: ROBSIM user's guide

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    The purpose of the Robotics Simulation Program is to provide a broad range of computer capabilities to assist in the design, verification, simulation, and study of robotics systems. ROBSIM is program in FORTRAN 77 for use on a VAX 11/750 computer under the VMS operating system. This user's guide describes the capabilities of the ROBSIM programs, including the system definition function, the analysis tools function and the postprocessor function. The options a user may encounter with each of these executables are explained in detail and the different program prompts appearing to the user are included. Some useful suggestions concerning the appropriate answers to be given by the user are provided. An example user interactive run in enclosed for each of the main program services, and some of the capabilities are illustrated

    Development of MBD Model and Analysis Methodology for Vehicle Design

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    This thesis is to provide a new methodology that considers the effects the chassis applies during dynamic load to the suspension and the handling characteristics of a road course vehicle. A methodology in which is described in detail as well as an applied demonstration where literature before this thesis, lacks in replication and serves to establish a basis for multi-body dynamic analysis in this area. Two models to be created, rigid and flexible, and to compare each other to study the effects the chassis torsional stiffness has during load transfer. Ultimately, to assist in the design of a vehicle that takes into account the effects studied in this thesis

    ADVANCED LATTICE AND POROUS STRUCTURES FOR AM PRODUCT OPTIMIZATION

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    The present work aims at favoring development of strategies useful for innovative high-performance mechanical components design. One of the most promising but not yet adequately explored strategies to achieve this goal are lattice / porous structures to be used as structural or filler materials to increase performance in terms of stiffness to weight ratio and enhanced vibration damping. To fill this knowledge gap, static and dynamic behavior of SLM-manufactured lattice structures made in AlSi10Mg aluminum alloy and 316L austenitic stainless steel have been thoroughly investigated; in particular, the study allowed to observe the effect of lattice\u2019s unit cell geometry and overall size variation on its mechanical properties, focusing on damping performances. Acquired knowledge allowed to develop a versatile methodology that can be applied to assess the mechanical properties of different kinds of lattice / porous structures, facilitating FE models calibration, creation of homogenization methods and mathematical models useful for lattices static and dynamic behavior rapid estimation. The development of an innovative tool for in-process measurement of cutting forces that develop in milling, drilling and grinding, integrating specially designed lattice structures, represents a practical case study useful to assess the feasibility of exploiting lattice structures to enhance mechanical components performances. Transversal expertise gained with respect to the SLM process, design and optimization of mechanical components and lattice structures, allowed to develop and validate an innovative methodology for rapid production of small-sized lattice structures (Patent Pending). An appropriate experimental campaign allowed to identify optimized process parameters, suitable for the production of lattices using the proposed methodology. The proposed method enhances the overall manufacturing process efficiency; moreover, since it allows substantial savings in terms of time and costs it has both scientific and industrial relevance

    The programmable spring: towards physical emulators of mechanical systems

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    The way motion is generated and controlled in robotics has traditionally been based on a philosophy of rigidity, where movements are tightly controlled and external influences are ironed out. More recent research into autonomous robots, biological actuation and human machine interaction has uncovered the value of compliant mechanisms in both aiding the production of effective, adaptive and efficient behaviour, and increasing the margins for safety in machines that operate alongside people. Various actuation methods have previously been proposed that allow robotic systems to exploit rather than avoid the influences of external perturbations, but many of these devices can be complex and costly to engineer, and are often task specific. This thesis documents the development of a general purpose modular actuator that can emulate the behaviour of various spring damping systems. It builds on some of the work done to produce reliable force controlled electronic actuators by developing a low cost implementation of an existing force actuator, and combining it with a novel high level control structure running in software on an embedded microcontroller. The actuator hardware with its embedded software results in a compact modular device capable of approximating the behaviour of various mechanical systems and actuation devices. Specifying these behaviours is achieved with an intuitive user interface and a control system based on a concept called profile groups. Profile group configurations that specify complex mechanical behaviours can be rapidly designed and the resulting configurations downloaded for a device to emulate. The novel control system and intuitive user interface developed to facilitate the rapid prototyping of mechanical behaviours are explained in detail. Two prototype devices are demonstrated emulating a number of mechanical systems and the results are compared to mechanical counterparts. Performance issues are discussed and some solutions proposed alongside general improvements to the control system. The applications beyond robotics are also explored

    Redesign of the Cam Dynamics Test Machine

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    The Cam Dynamics Test Machine (CDTM) was made to demonstrate cam operation and to test the dynamics of industrial cam-follower systems. Recent modifications made it inoperable in a classroom setting and revealed damage-causing flaws in the initial design. This project encompassed the redesign of the follower trains to eliminate those flaws. It also made the machine function in a classroom, improved the electrical wiring, and added storage space. Finally, the sensors were connected to a data acquisition board, and a Virtual Instrument was written to interpret their output voltages to aid future experimentation
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