Stable Haptic Rendering Using a Pipelined Threading Architecture

The emergence of low cost hap tic devices and the evolution of technologies for developing virtual reality environments for web have motivated the development of tools that allow the use of hap tic systems together with applications and web browsers. The availability of web hap tic systems results on the possibility of multisensory experiences for internet users. This paper analyzes technologies for integrating hap tic and web systems, exposing the features of each tool in order to find the best strategy to incorporate virtual touch in Museu3l by using the hap tic technology, so that it becomes one of the first virtual museums that makes hap tic interaction with a work of art in a web visit possible.

Smooth haptic force feedback is an important task for multirate 6-DOF haptic rendering for both rigid and deformable objects. The update rate of the haptic force may be too low and changed during the simulation as the high computation time is required for complex physical simulation. Therefore, to implement a stable and smooth haptic rendering, we need a method to update the force in a higher regular rate during the physical simulation. We propose a prediction method using interpolation to calculate smooth haptic interaction force in a high update rate. The auto-regressive model is used to predict the force value based on the previous haptic force calculation. In addition, we introduce a spline function to interpolate force values for the haptic force output. We demonstrate that the proposed method can provide smooth and accurate haptic force feedback in a high update rate during a low frequency physical simulation of complex and deformable models. In the experiments, we show the feasibility of the proposed method and compare its accuracy and stability with the linear force prediction algorithm.

We show a novel encountered‐type haptic system, H‐Wall, to enable haptic feedback using a manipulator of seven degrees of freedom suitable for simulating indoor virtual reality environments, which are characterized and confined by a set of vertical walls and revolving doors. At runtime, our system tracks hand motion using a red–green–blue depth sensor and locates its configuration. Then, the robotic manipulator plans a trajectory for the end effector, attached to a rectangular rigid board, to make contact with the hand to deliver a sense of touch as long as the perceived hand contact force is substantial. The force feedback is generated in a passive sense for static walls that the rigid board, corresponding to a vertical wall, holds its position as long as the perceived hand contact force is substantial. For a revolving door, the force feedback is generated in an active sense based on impedance control. In order to address the issue of limited workspace, we also propose a new reachability map, calledper‐plane reachability map, that is optimized to answer whether passive haptic feedback can be generated by a manipulator when the user touches a vertical wall at a given orientation. We successfully demonstrate our system to provide an illusion to the user in a virtual environment with touch sensation to the surrounding environment.

This paper presents a control method using an adjusting output-limiter for stable haptic rendering in a virtual environment. In a simulation of force-reflecting interaction with deformable objects in a virtual environment, a quick computation of the accurate impedance of deformable objects is rare. This is particularly true when physics-based models, such as tensor-mass models or mass-spring models, are used. The problem is aggravated if the simulation involves changes in the geometry and/or impedance of the deformation model, such as cutting or suturing. The proposed control method guarantees stable haptic interactions with deformable objects of unknown and/or varying impedance. The method is based on the time-domain passivity theorem and the two-port network model. The controller adjusts the maximum permissible force to guarantee the passivity of the haptic system at every sampling instant. The controller notes only the magnitude of the reflective force, and does not depend on properties of the employed force model. This allows the proposed control method applicable to haptic systems involving deformable objects with unknown, nonlinear, and/or time-varying impedance. Designs of the controllers are presented for impedance-type and admittance-type haptic systems. The method is also extended for multiple degrees-of-freedom.

In our everyday lives the fundamental role played by sensory systems, such as vision, hearing, and touch, is often taken for granted. Most of the information for the cognitive mapping of spaces used by people who are sighted is gathered through the visual channel. Unfortunately, people who are blind or have low vision lack the ability to collect the required visual information either in advance or in-situ. Indeed, for people who are blind an unknown environment can be unpleasant, uncomfortable, and unsafe even after extensive orientation and mobility rehabilitation training. In this study we developed a new virtual environment system for people who are blind to aid them in their anticipatory exploration and cognitive mapping of unknown environments. The two main goals of the study were: (1) to develop and assess an integrated haptic and audio virtual environment system though which people who are blind can explore a virtual map of an unknown real space and (2) to study the cognitive mapping process of people who are blind when using the virtual environment. The findings supply strong evidence that interaction with the BlindAid system by people who are blind provided a robust foundation for the participantspsila development of comprehensive cognitive maps of real unknown spaces. In conjunction with these results, the userspsila performance within the virtual environment supplied an assessment tool for orientation and mobility specialists. (Supported by a grant from National Eye Institute, NIH.).

Purpose – This paper aims to report the development and key features of a novel virtual reality system for assembly planning and evaluation called Haptic Assembly and Manufacturing System (HAMS). The system is intended to be used as a tool for training, design analysis and path planning. Design/methodology/approach – The proposed system uses the physics-based modelling (PBM) to perform assemblies in virtual environments. Moreover, dynamic assembly constrains have been considered to reduce the degrees of freedom of virtual objects and enhance the virtual assembly performance. Findings – To evaluate the effectiveness and performance of HAMS, the assembly of various mechanical components has been carried out, and the results have shown that it can be effectively used to simulate, evaluate, plan and automatically formalise the assembly of complex models in a more natural and intuitive way. Research limitations/implications – The collision detection performance is the bottleneck in any virtual assembly system. New methods of collision shape representation and collision detection algorithms must be considered. Originality/value – HAMS introduces the use of dynamic assembly constraints to enhance the virtual assembly performance. HAMS also uses features not yet reported by similar systems in the literature. These features include: automatic or manual definition of assembly constraints within the virtual assembly system; the implementation of control panels and widgets to modify simulation parameters during running time to evaluate its influence on simulation performance; assembly data logging such as trajectories, forces and update rates for post-processing, further analysis or its presentation in the form of chronocyclegraphs to graphically analyse the assembly process.

This paper describes a novel haptic mouse system which conveys kinesthetic and tactile information simultaneously in virtual environments. The haptic mouse system can provide 2-DOF translational force feedback, vibration, normal pressure, skin stretch and thermal feedback, all of which are important physical quantities of sensing object's shape, stiffness and surface properties. The system can simulate small scale shapes and roughness of surface textures using cutaneous cues generated by individual drives of a 6/spl times/8 pin array. Since thermal differences among surfaces of virtual objects is one of dominant factors in perceiving texture, a thermal feedback unit composed of a heat conduction plate and a temperature sensor is also embedded into the tactile display system. The developed system can be used as a testbed in psychophysical study on tactile perception. We have investigated the influence of the frequency variation on perceived roughness using the haptic mouse system since vibrotaction has been considered as a key factor affecting perception of fine textures by physiology researchers. In order to find out the relation of roughness and vibration, two psychophysical experiments have been performed. The correlation between the vibration frequency and the texture shows that there are certain transitions of perceived roughness. The experimental results yield that the vibrating stimulus is more effective for displaying a fine surface than static displacement display, and it shows a possibility to display finer texture, exceeding the physical limitation of the device.

Force display using a hybrid haptic device composed of motors and brakes

The use of journal clubs and, more recently, case-based discussions in order to stimulate debate among orthopaedic surgeons lies at the heart of orthopaedic training and education. A virtual learning environment can be used as a platform to host virtual journal clubs and case-based discussions. This has many advantages in the current climate of constrained time and diminishing trainee and consultant participation in such activities. The virtual environment model opens up participation and improves access to journal clubs and case-based discussions, provides reusable educational content, establishes an electronic record of participation for individuals, makes use of multimedia material (including clinical imaging and photographs) for discussion, and finally, allows participants to link case-based discussions with relevant papers in the journal club. The Leicester experience highlights the many advantages and some of the potential difficulties in setting up such a virtual system and provides useful guidance for those considering such a system in their own training programme. As a result of the virtual learning environment, trainee participation has increased and there is a trend for increased consultant input in the virtual journal club and case-based discussions. It is likely that the use of virtual environments will expand to encompass newer technological approaches to personal learning and professional development.

The goal of this paper is to develop haptic-visual interaction training system for aircraft fuel supply simulation. Operators can use this system to simulate refueling aircraft in virtual environment with tactile and visual feedback. The simulator is built based on haptic device Omega 3DOF. Hardware and software are discussed to meet the requirement of training simulation. Experiment results show that the system can provide stable simulation of aircraft refueling operation. For aviation engineers, fuel supply is an operation to use fuel supply system to refuel aircrafts. The structures of refueling system and aircraft fuel tank are complex. Moreover, the evaporated fuel may pollute the environment and cause explosion in the refueling process. Therefore, the aviation engineers should strictly obey the operating rules and expertly grasp the skill to refuel aircraft. They should take sufficient time for a long practice in aircraft refueling. Now, the cultivation of aviation engineers' refueling operation includes watching demo to learn the operating rule and actual operation with the guiding of teachers. After watching the correct refueling operation and learning the operating rule, operators may finish the refueling operation with the instruction of the professional. However, they need to practice enough times to grasp this skill, and the instruction of teacher is necessary in the whole training process. This training needs a long period to cultivate an eligible operator and the cost is high. Therefore, a haptic interaction system realistically mimicking refueling environment would significantly contribute to the improvement of refueling operation training. The aircraft refueling training system is a haptic interaction system with the capacity of haptic-visual display. Operators can use it to simulate aircraft refueling operation in a virtual environment and can sense haptic-visual feedback that is similar to that of the same operation in physical world. The operators can learn the operating rules and grasp the operating skill based on virtual operation. It will help to reduce the time and the cost of actual operation for refueling operation training.

This paper discusses the proposed model of the collaborative virtual learning system for the introductory computer programming course which uses one of the collaborative learning techniques known as the “Think-Pair-Share”. The main objective of this study is to design a model for an online learning system that facilitates the collaborative learning activities in a virtual environment such as online communications and pair or small group discussions. In order to model the virtual learning environment, the RUP methodology has been used where it involves the data collection phase and the analysis and design phase. Fifty respondents have been randomly selected to participate in the data collection phase to investigate the students’ interest and learning styles as well as their learning preferences. The results have shown the needs for the development of online small group discussions that can be used as an alternative learning style for programming courses. The proposed design of the virtual learning system named as the Online Collaborative Learning System or OCLS is being depicted using the objectoriented models which are the use-case model and class diagram in order to show the concise processes of virtual “Think-Pair-Share” collaborative activities. The “Think-PairShare” collaborative learning technique that is being used in this model has been chosen because of its simplicity and relatively low-risk. This paper also presents the proposed model of the system’s architecture that will become the guidelines for the physical development of OCLS using the web-based applications.

This paper presents a real-time outside-in camera-based tracking system for wireless 3D pose tracking of a user’s head and hand in a virtual environment. The system uses four unsynchronised cameras as sensors and passive retroreflective markers arranged in rigid bodies as targets. In order to achieve high update rates and to cope with the unsynchronised data a single-constraint-at-a-time (SCAAT) Extended Kalman Filtering approach is used that recursively integrates measurements as soon as they are available one-at-a-time. Tests show that this approach is more robust to occlusions and provides less noisy pose estimates with a higher update rate than a conventional stereo triangulation approach.

Virtual reality (VR) is a rapidly developing technology that has a wide spectrum of industrial and commercial applications. Networked (distributed or shared) virtual environments (VE) are of growing interest to modern manufacturing industry; a dominating use of networked virtual manufacturing environments (VMEs) is on-line visualisation and collaborative control of 3D information. This has to be supported by real-time data transfer. To meet a broad range of common requirements for Internet-based VE communications, particularly for virtual manufacturing and collaborative design and control, this paper presents a networked virtual environment system that is designed to support networked virtual design and manufacturing. The system is implemented with manufacturing message specification (MMS) standards so as to integrate a range of manufacturing services into networked VEs over the Internet.

The usability of virtual reality (VR) controller interfaces are often complex and difficult for first time users. Most controllers provide minimal feedback which relegates the potential for heightened interaction and feedback within virtual experiences. This research explores how haptic technology systems partnered with VR can deliver immersive interactions between user and virtual environment (VE). This research involves the development of a haptic glove interface prototype that incorporates a force feedback and vibrotactile feedback system. It focuses on determining a workflow that communicates in real-time user interaction and environmental feedback using Unreal Engine and the produced haptic glove system. Testing and calibrating the prototype feedback system provided a baseline for developers to rationalise and improve accuracy of current real-time virtual feedback systems. The evaluation of this research in industry unfolds new technical knowledge for implementing a wider range of haptic technologies within VR. This further development would involve reviewing the usability and interaction standards for VR users in the design process.

To date, haptic interfaces have rarely been used to display complex virtual environments such as those involving 3D mechanical assembly operations, or the use of hand tools. Of the limitations which have been encountered, one is the absence of suitable simulation techniques which provide a general, user-defined virtual environment. This paper discusses the use of an impulse-based simulation as a general purpose multibody simulator for haptic display. This technique uses Poisson’s hypothesis in conjunction with Coulomb friction as the basis of the contact model. Since haptic displays are required to run in real time with a constant step size and high update rate, changes to the algorithm are required. We identify the “impact state” as a critical feature of the contact model, and outline the various ways it can be chosen. Finally, we describe the implementation of a planar multibody simulator on one and two-axis haptic displays.