A virtual work space for both hands manipulation with coherency between kinesthetic and visual sensation

This paper describes the construction of a virtual work space for tasks performed by two handed manipulation. We intend to provide a virtual environment that encourages users to accomplish tasks as they usually act in a real environment. Our approach uses a three dimensional spatial interface device that allows the user to handle virtual objects by hand and be able to feel some physical properties such as contact, weight, etc. We investigated suitable conditions for constructing our virtual work space by simulating some basic assembly work, a face and fit task. We then selected the conditions under which the subjects felt most comfortable in performing this task and set up our virtual work space. Finally, we verified the possibility of performing more complex tasks in this virtual work space by providing simple virtual models and then let the subjects create new models by assembling these components. The subjects can naturally perform assembly operations and accomplish the task. Our evaluation shows that this virtual work space has the potential to be used for performing tasks that require two-handed manipulation or cooperation between both hands in a natural manner

Motion planning and assembly for microassembly workstation

In general, mechatronics systems have no standard operating system that could be used for planning and control when these complex devices are running. The goal of this paper is to formulate a work platform that can be used as a method for obtaining precision in the manipulation of micro-entities using micro-scale manipulation tools for microsystem applications. This paper provide groundwork for motion planning and assembly of the Micro-Assembly Workstation (MAW) manipulation system. To demonstrate the feasibility of the idea, the paper implements some of the motion planning algorithms; it investigates the performance of the conventional Euclidean distance algorithm (EDA), artificial potential fields’ algorithm, and A* algorithm when implemented on a virtual space

Haptic Feedback to Guide Interactive Product Design

Virtual Reality (VR) allows engineers to naturally interact with three-dimensional digital models in a three-dimensional space. This provides a unique interface between users and computer models not found in traditional desktop environments. Common uses of virtual reality in product design include prototype evaluation, virtual assembly and visualization of engineering analysis results. This work described in this paper is based on a methodology for interactive design that uses virtual reality as an interface to product design and analysis. Computer analysis models coupled with fast reanalysis approximations and geometric models in a virtual environment are developed to facilitate shape design changes and updated analysis results in real-time. This combined design and analysis environment encourages the rapid investigation of many possible shape and design changes and how they affect the final product performance. The application developed to test this methodology is referred the Immersive Virtual Design Application (IVDA)

Automation and Robotics for Space-Based Systems, 1991

The purpose of this in-house workshop was to assess the state-of-the-art of automation and robotics for space operations from an LaRC perspective and to identify areas of opportunity for future research. Over half of the presentations came from the Automation Technology Branch, covering telerobotic control, extravehicular activity (EVA) and intra-vehicular activity (IVA) robotics, hand controllers for teleoperation, sensors, neural networks, and automated structural assembly, all applied to space missions. Other talks covered the Remote Manipulator System (RMS) active damping augmentation, space crane work, modeling, simulation, and control of large, flexible space manipulators, and virtual passive controller designs for space robots

Using a Visualization Tool for Studying the Effects of Virtual Environments on Assembly Training

The objective of this research is to build and demonstrate the design on Virtual Reality (VR) environment to aid in the understanding of assembly & assembly planning for complex systems. To explain the research work, a Virtual Reality environment was created for assembly simulation of Treadmill parts used in a Spacecraft. This environment will account for space related constraint such as, gravity. This study will help in understanding the assembly of the VR model which might help an assembler to optimize the design related cost. Unity 3D is used for creating the VR environment along with Solidworks to create Treadmill parts. Text and image cues are offered to assist users while performing manual assembly. The assembly sequence followed by users will be compared with an optimized path sequence computed using a Genetic Algorithm for a collision-free layout. To validate the research work, the virtual assembly simulation has been run on four distinct set ups using immersive (VIVE headset) and non-immersive (desktop) virtual reality systems. A series of user studies to achieve two primary objectives has been conducted: 1) Evaluation of simulated representations with respect to different analysis, 2) Identification of best layout in terms of correctness and elapsed time for a virtual environment. A visualization tool was employed to analyze the system and data collected from diverse set ups. An interactive visualization tool based on a Tree-Map visualization technique was developed to represent the hidden patterns in users’ behavior when they perform different tasks in a virtual environment (using head-mounted VR tool and monitor based VR) which also help in concluding that immersive virtual reality with image cue appear to be the best set up in terms of correctness and time. In addition, using this interactive visualization tool, we show the intrinsic statistical relationships between/within diverse groups of participants in the form of chord diagrams.Computer Scienc

Virtual Electrode Design for Lithium-Ion Battery Cathodes

Microstructural characteristics of lithium‐ion battery cathodes determine their performance. Thus, modern simulation tools are increasingly important for the custom design of multiphase cathodes. This work presents a new method for generating virtual, yet realistic cathode microstructures. A precondition is a 3D template of a commercial cathode, reconstructed via focused ion beam/scanning electron microscopy (FIB/SEM) tomography and appropriate algorithms. The characteristically shaped micrometer‐sized active material (AM) particles and agglomerates of nano‐sized carbon‐binder (CB) particles are individually extracted from the voxel‐based templates. Thereby, a library of roughly 1100 AM particles and 20 CB agglomerates is created. Next, a virtual cathode microstructure is predefined, and representative sets of AM particles and CB agglomerates are built. The following re‐assembly of AM particles within a predefined volume box works using dropping and rolling algorithms. Thereby, one can generate cathodes with specified characteristics, such as the volume fraction of AM, CB and pore space, particle‐size distributions, and gradients thereof. Naturally, such a virtual twin is a promising starting point for physics‐based electrochemical performance models. The workflow from the commercial cathode microstructure through to a full virtual twin will be explained and assessed for a blend cathode made of the two AMs, LiNiCoAlO$_{2}$ (NCA) and LiCoO$_{2}$ (LCO)

Modal Abstractions for Virtualizing Memory Addresses

Operating system kernels employ virtual memory management (VMM) subsystems to virtualize the addresses of memory regions in order to to isolate untrusted processes, ensure process isolation and implement demand-paging and copy-on-write behaviors for performance and resource controls. Bugs in these systems can lead to kernel crashes. VMM code is a critical piece of general-purpose OS kernels, but their verification is challenging due to the hardware interface (mappings are updated via writes to memory locations, using addresses which are themselves virtualized). Prior work on VMM verification has either only handled a single address space, trusted significant pieces of assembly code, or resorted to direct reasoning over machine semantics rather than exposing a clean logical interface. In this paper, we introduce a modal abstraction to describe the truth of assertions relative to a specific virtual address space, allowing different address spaces to refer to each other, and enabling verification of instruction sequences manipulating multiple address spaces. Using them effectively requires working with other assertions, such as points-to assertions in our separation logic, as relative to a given address space. We therefore define virtual points-to assertions, which mimic hardware address translation, relative to a page table root. We demonstrate our approach with challenging fragments of VMM code showing that our approach handles examples beyond what prior work can address, including reasoning about a sequence of instructions as it changes address spaces. All definitions and theorems mentioned in this paper including the operational model of a RISC-like fragment of supervisor-mode x86-64, and a logic as an instantiation of the Iris framework, are mechanized inside Coq

Self-Replicating Machines in Continuous Space with Virtual Physics

JohnnyVon is an implementation of self-replicating machines in continuous two-dimensional space. Two types of particles drift about in a virtual liquid. The particles are automata with discrete internal states but continuous external relationships. Their internal states are governed by finite state machines but their external relationships are governed by a simulated physics that includes Brownian motion, viscosity, and spring-like attractive and repulsive forces. The particles can be assembled into patterns that can encode arbitrary strings of bits. We demonstrate that, if an arbitrary "seed" pattern is put in a "soup" of separate individual particles, the pattern will replicate by assembling the individual particles into copies of itself. We also show that, given sufficient time, a soup of separate individual particles will eventually spontaneously form self-replicating patterns. We discuss the implications of JohnnyVon for research in nanotechnology, theoretical biology, and artificial life

A virtual environment for the design and simulated construction of prefabricated buildings

The construction industry has acknowledged that its current working practices are in need of substantial improvements in quality and efficiency and has identified that computer modelling techniques and the use of prefabricated components can help reduce times, costs, and minimise defects and problems of on-site construction. This paper describes a virtual environment to support the design and construction processes of buildings from prefabricated components and the simulation of their construction sequence according to a project schedule. The design environment can import a library of 3-D models of prefabricated modules that can be used to interactively design a building. Using Microsoft Project, the construction schedule of the designed building can be altered, with this information feeding back to the construction simulation environment. Within this environment the order of construction can be visualised using virtual machines. Novel aspects of the system are that it provides a single 3-D environment where the user can construct their design with minimal user interaction through automatic constraint recognition and view the real-time simulation of the construction process within the environment. This takes this area of research a step forward from other systems that only allow the planner to view the construction at certain stages, and do not provide an animated view of the construction process