scholarly journals BREP Identification During Voxel-Based Collision Detection for Haptic Manual Assembly

2011 ◽  
Author(s):  
Daniela Faas ◽  
Judy M. Vance
Keyword(s):  
Collision Detection ◽  
Force Feedback ◽  
Boundary Representation ◽  
Small Subset ◽  
Manual Assembly ◽  
Assembly Simulation ◽  
Geometric Boundary ◽  
Novel Method ◽  
Constraint Enforcement ◽  
Assembly Tasks

This paper presents a novel method to tie geometric boundary representation (BREP) to voxel-based collision detection for use in haptic manual assembly simulation. Virtual Reality, in particular haptics, has been applied with promising results to improve preliminary product design, assembly prototyping and maintenance operations. However, current methodologies do not provide support for low clearance assembly tasks, reducing the applicability of haptics to a small subset of potential situations. This paper discusses a new approach, which combines highly accurate CAD geometry (boundary representation) with voxel models to support a hybrid method involving both geometric constraint enforcement and voxel-based collision detection to provide stable haptic force feedback. With the methods presented here, BREP data can be accessed during voxel-based collision detection. This information can be used for constraint recognition and lead to constraint-guidance during the assembly process.

scholarly journals A Hybrid Method for Haptic Feedback to Support Manual Virtual Product Assembly

2011 ◽  
Author(s):  
Daniela Faas
Keyword(s):  
Collision Detection ◽  
Simulation Training ◽  
Force Feedback ◽  
Haptic Feedback ◽  
Boundary Representation ◽  
Virtual Training ◽  
Assembly Simulation ◽  
Assembly Operations ◽  
Product Assembly ◽  
Virtual Product

Experience with current Virtual Reality (VR) systems that simulate low clearance assembly operations with haptic feedback indicate that such systems are highly desirable tools in the evaluation of preliminary designs, as well as virtual training and maintenance processes. The purpose of this research is to develop methods to support manual low clearance assembly using haptic (force) feedback in a virtual environment. The results of this research will be used in an engineering framework for assembly simulation, training, and maintenance. The proposed method combines voxel-based collision detection and boundary representation to support both force feedback and constraint recognition. The key to this approach is developing the data structure and logic needed to seamlessly move between the two representations while supporting smooth haptic feedback. Collision forces and constraint-guided forces are blended to provide support for low clearance haptic assembly. This paper describes the development of the method.

Virtual Mechanical Assembly on a PC-Based System

1996 ◽  
Author(s):  
E. Pere ◽  
N. Langrana ◽  
D. Gomez ◽  
G. Burdea
Keyword(s):  
Virtual Reality ◽  
Mechanical Behavior ◽  
Collision Detection ◽  
Force Feedback ◽  
Object Manipulation ◽  
Virtual Reality System ◽  
Mechanical Assembly ◽  
Training Task ◽  
Virtual Tools ◽  
Assembly Tasks

Abstract This paper describes a virtual reality system in which the user can perform assembly tasks in a simulated workshop. This PC-based VR system integrates a force feedback device, the Rutgers Master II. It allows the user to feel the interaction with virtual tools and makes the training task in a synthetic environment closer to reality. The application also allows object manipulation with mechanical behavior, navigation, collision detection and other features.

scholarly journals A Magnetorheological Fluids-Based Robot-Assisted Catheter/Guidewire Surgery System for Endovascular Catheterization

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 640
Author(s):  
Linshuai Zhang ◽  
Shuoxin Gu ◽  
Shuxiang Guo ◽  
Takashi Tamiya
Keyword(s):  
Collision Detection ◽  
Endovascular Procedures ◽  
Force Feedback ◽  
Force Measurement ◽  
Occupational Hazards ◽  
Robot Assisted ◽  
X Ray ◽  
Surgical Safety ◽  
Surgical Tool ◽  
Haptic Cues

A teleoperated robotic catheter operating system is a solution to avoid occupational hazards caused by repeated exposure radiation of the surgeon to X-ray during the endovascular procedures. However, inadequate force feedback and collision detection while teleoperating surgical tools elevate the risk of endovascular procedures. Moreover, surgeons cannot control the force of the catheter/guidewire within a proper range, and thus the risk of blood vessel damage will increase. In this paper, a magnetorheological fluid (MR)-based robot-assisted catheter/guidewire surgery system has been developed, which uses the surgeon’s natural manipulation skills acquired through experience and uses haptic cues to generate collision detection to ensure surgical safety. We present tests for the performance evaluation regarding the teleoperation, the force measurement, and the collision detection with haptic cues. Results show that the system can track the desired position of the surgical tool and detect the relevant force event at the catheter. In addition, this method can more readily enable surgeons to distinguish whether the proximal force exceeds or meets the safety threshold of blood vessels.

scholarly journals Observing merger trees in a new light

2018 ◽  
Vol 35 ◽  
Author(s):  
Rhys J. J. Poulton ◽  
Aaron S. G. Robotham ◽  
Chris Power ◽  
Pascal J. Elahi
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Diagnostic Tool ◽  
Cosmic Time ◽  
Analytical Models ◽  
Dark Matter Halos ◽  
Assembly Simulation ◽  
Novel Method ◽  
Tree Building

AbstractMerger trees harvested from cosmologicalN-body simulations encode the assembly histories of dark matter halos over cosmic time and are a fundamental component of semi-analytical models of galaxy formation. The ability to compare the tools used to construct merger trees, namely halo finders and tree building algorithms, in an unbiased and systematic manner is critical to assess the quality of merger trees. In this paper, we present the dendrogram, a novel method to visualise merger trees, which provides a comprehensive characterisation of a halo’s assembly history—tracking subhalo orbits, halo merger events, and the general evolution of halo properties. We show the usefulness of thedendrogramas a diagnostic tool of merger trees by comparing halo assembly simulation analysed with three different halo finders—VELOCIraptor, AHF, and Rockstar—and their associated tree builders. Based on our analysis of the resulting dendrograms, we highlight how they have been used to motivate improvements to VELOCIraptor. Thedendrogramsoftware is publicly available online, at:https://github.com/rhyspoulton/MergerTree-Dendrograms.

Collision Detection

2011 ◽  
pp. 36-67
Author(s):  
Gabriel Zachmann
Keyword(s):  
Virtual Reality ◽  
Real Time ◽  
Collision Detection ◽  
Serious Games ◽  
Medical Training ◽  
Virtual Assembly ◽  
Virtual Objects ◽  
Enabling Technologies ◽  
Assembly Simulation ◽  
Physically Based

Collision detection is one of the enabling technologies in many areas, such as virtual assembly simulation, physically-based simulation, serious games, and virtual-reality based medical training. This chapter will provide a number of techniques and algorithms that provide efficient, real-time collision detection for virtual objects. They are applicable to various kinds of objects and are easy to implement.

Haptic Wrists: An Alternative Design Strategy Based on User Perception

2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Javier Martín ◽  
Joan Savall ◽  
Iñaki Díaz ◽  
Josune Hernantes ◽  
Diego Borro
Keyword(s):  
Collision Detection ◽  
Design Problem ◽  
Force Feedback ◽  
Mechanical Design ◽  
Design Strategy ◽  
User Perception ◽  
Satisfactory Solution ◽  
Alternative Design ◽  
Three Degree Of Freedom ◽  
Mechanical Design Problem

A new three degree-of-freedom (3DOF) torque feedback wrist is being developed to be added to an existing 3DOF force feedback haptic device. It is difficult to find a satisfactory solution to the mechanical design problem, mainly because of the required large rotational workspace and severe weight constraints. This work proposes an alternative design strategy based on user perception, which allows simplification of the mechanics. The proposed approach consists of substituting the last rotational DOF of the wrist with a pseudohaptic DOF. Thanks to specially designed visuotactile cues, the pseudohaptic DOF is integrated with the active DOF into the same device, being able to generate free motion and collision detection perception to the user. This approach provides for simpler kinematics, lightweight designs, lower inertias, and less friction, which are key advantages for the inclusion of torque feedback into force feedback devices.

Machining Complex Three-Dimensional Nanostructures With an Atomic Force Microscope Through the Frequency Control of the Tip Reciprocating Motions

2016 ◽  
Vol 138 (12) ◽  
Author(s):  
Yanquan Geng ◽  
Yongda Yan ◽  
Emmanuel Brousseau ◽  
Xing Cui ◽  
Bowen Yu ◽  
...  
Keyword(s):  
Atomic Force Microscope ◽  
Force Feedback ◽  
Normal Load ◽  
Frequency Control ◽  
Three Dimensional ◽  
Atomic Force ◽  
Combined Control ◽  
Novel Method ◽  
Lateral Displacements ◽  
Floor Surfaces

A novel method relying on atomic force microscope (AFM) tip based nanomachining is presented to enable the fabrication of microchannels that exhibit complex three-dimensional (3D) nanoscale floor surface geometries. To achieve this, reciprocating lateral displacements of the tip of an AFM probe are generated, while a high-precision stage is also actuated to move in a direction perpendicular to such tip motions. The width and length of microchannels machined in this way are determined by the amplitude of the tip motion and the stage displacement, respectively. Thus, the processing feed can be changed during the process as it is defined by the combined control of the frequency of the tip reciprocating motions and the stage speed. By employing the built-in force feedback loop of conventional AFM systems during such operations, the variation of the feed leads to different machined depths. Thus, this results in the capability to generate complex 3D nanostructures, even for a given normal load, which is set by the AFM user prior to the start of the process. In this paper, the fabrication of different microchannels with floor surfaces following half triangular, triangular, sinusoidal, and top-hat waveforms is demonstrated. It is anticipated that this method could be employed to fabricate complex nanostructures more readily compared to traditional vacuum-based lithography processes.

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