scholarly journals A Novel Virtual 3D Brush Model Based on Variable Stiffness and Haptic Feedback

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Lei Huang ◽  
Zengxuan Hou
Keyword(s):  
Real Time ◽  
Haptic Feedback ◽  
Average Distance ◽  
Weighted Average ◽  
Variable Stiffness ◽  
Virtual Object ◽  
Input Device ◽  
Sampling Point ◽  
Time Deformation ◽  
Brush Model

A novel variable stiffness 3D virtual brush model and haptic decoration technique suitable for the surface of the three-dimensional objects for the automobile industry are introduced based on real-time haptic feedback mechanism using a 6 DOFs input device, and the haptic behavior of an expressive virtual 3D brush with variable stiffness is studied in detail for the first time. First, the intrinsic mechanism between the deformation of real hair brush and the applied external forces (such as the bending moment) is analyzed and studied in detail by introducing a bending spring to express the basic mechanical behavior for the 3D hair brush. Based on this brush model, many important painting features can be simulated, such as the softer brush tip, brush flattening, and bristle spreading. And a useful algorithm (named the weighted-average distance) for dealing with collision checking among the two objects (3D clay and the 3D brush) is presented. As long as the brush head is close to the 3D object, within a tolerance range, the computational tactile sensation force will be emerged, and the interactive painting process is implemented actually on the outer surface of the virtual object. We then calculate the related bounding ball for deformed 3D brush using a fast ball-expanding search algorithm to determine the virtual projection plane. Based on the real-time deformation about the virtual brush head at a sampling point, the 2D painting footprints, which is produced between the brush head and virtual projection painting plane, is calculated and rendered. Next, the 3D painting footprint could be easily produced via mapping the 2D painting footprints onto the surface of the 3D model in real time. Finally, the 3D painting strokes are formed via controlling the exerted force and overlapping the virtual 3D painting footprints with different shape, size, and following the moving direction of the 3D brush. Experiment result shows that the adopted method can effectively enhance reality to users, with high performance.

scholarly journals Multi-Fingered Grasping and Manipulation in Virtual Environments Using an Isometric Finger Device

2007 ◽  
Vol 16 (3) ◽  
pp. 293-306 ◽  
Author(s):  
Gregorij Kurillo ◽  
Matjaž Mihelj ◽  
Marko Munih ◽  
Tadej Bajd
Keyword(s):  
Virtual Reality ◽  
Muscle Strength ◽  
Virtual Environments ◽  
Healthy Subjects ◽  
Haptic Feedback ◽  
Virtual Object ◽  
Input Device ◽  
Haptic Information ◽  
Stroke Patients ◽  
Post Stroke

In this article we present a new isometric input device for multi-fingered grasping in virtual environments. The device was designed to simultaneously assess forces applied by the thumb, index, and middle finger. A mathematical model of grasping, adopted from the analysis of multi-fingered robot hands, was applied to achieve multi-fingered interaction with virtual objects. We used the concept of visual haptic feedback where the user was presented with visual cues to acquire haptic information from the virtual environment. The virtual object corresponded dynamically to the forces and torques applied by the three fingers. The application of the isometric finger device for multi-fingered interaction is demonstrated in four tasks aimed at the rehabilitation of hand function in stroke patients. The tasks include opening the combination lock on a safe, filling and pouring water from a glass, muscle strength training with an elastic torus, and a force tracking task. The training tasks were designed to train patients' grip force coordination and increase muscle strength through repetitive exercises. The presented virtual reality system was evaluated in a group of healthy subjects and two post-stroke patients (early post-stroke and chronic) to obtain overall performance results. The healthy subjects demonstrated consistent performance with the finger device after the first few trials. The two post-stroke patients completed all four tasks, however, with much lower performance scores as compared to healthy subjects. The results of the preliminary assessment suggest that the patients could further improve their performance through virtual reality training.

scholarly journals The Simulation of the Brush Stroke Based on Force Feedback Technology

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Chao Guo ◽  
Zengxuan Hou ◽  
Guangqing Yang ◽  
Shuanzhu Zheng
Keyword(s):  
Real Time ◽  
Force Feedback ◽  
Morphological Changes ◽  
Simulation Method ◽  
Sampling Point ◽  
Mass Model ◽  
Brush Stroke ◽  
The Relationship ◽  
Brush Model ◽  
Painting System

A novel simulation method of the brush stroke is proposed by applying force feedback technology to the virtual painting process. The relationship between force and the brush deformation is analyzed, and the spring-mass model is applied to construct the brush model, which can realistically simulate the brush morphological changes according to the force exerted on it. According to the deformation of the brush model at a sampling point, the brush footprint between the brush and the paper is calculated in real time. Then, the brush stroke is obtained by superimposing brush footprints along sampling points, and the dynamic painting of the brush stroke is implemented. The proposed method has been successfully applied to the virtual painting system based on the force feedback technology. In this system, users can implement the painting in real time with a Phantom Desktop haptic device, which can effectively enhance reality to users.

scholarly journals Real‐Time Deformation with Coupled Cages and Skeletons

2020 ◽  
Vol 39 (6) ◽  
pp. 19-32
Author(s):  
F. Corda ◽  
J. M. Thiery ◽  
M. Livesu ◽  
E. Puppo ◽  
T. Boubekeur ◽  
...  
Keyword(s):  
Real Time ◽  
Time Deformation

scholarly journals Telemanipulation of an Articulated Robotic Arm using a Commercial Virtual Reality Controller

2020 ◽  
Vol 6 (3) ◽  
pp. 127-130
Author(s):  
Max B. Schäfer ◽  
Kent W. Stewart ◽  
Nico Lösch ◽  
Peter P. Pott
Keyword(s):  
Virtual Reality ◽  
Real Time ◽  
Robotic Arm ◽  
Input Device ◽  
Robot Assisted ◽  
Promising Alternative ◽  
Input Devices ◽  
Current Input ◽  
Current Systems ◽  
Robot Assisted Surgery

AbstractAccess to systems for robot-assisted surgery is limited due to high costs. To enable widespread use, numerous issues have to be addressed to improve and/or simplify their components. Current systems commonly use universal linkage-based input devices, and only a few applicationoriented and specialized designs are used. A versatile virtual reality controller is proposed as an alternative input device for the control of a seven degree of freedom articulated robotic arm. The real-time capabilities of the setup, replicating a system for robot-assisted teleoperated surgery, are investigated to assess suitability. Image-based assessment showed a considerable system latency of 81.7 ± 27.7 ms. However, due to its versatility, the virtual reality controller is a promising alternative to current input devices for research around medical telemanipulation systems.

Real-Time Deformation Simulation of Kidney Surgery Based on Virtual Reality

2021 ◽  
Vol 26 (3) ◽  
pp. 290-297
Author(s):  
Mengjie Jing ◽  
Zhixin Cui ◽  
Hang Fu ◽  
Xiaojun Chen
Keyword(s):  
Virtual Reality ◽  
Real Time ◽  
Time Deformation ◽  
Kidney Surgery ◽  
Deformation Simulation

WEIGHTED AVERAGE GEODESIC DISTANCE OF PENTADENDRITE NETWORKS

Fractals ◽  
2020 ◽  
Vol 28 (05) ◽  
pp. 2050075
Author(s):  
YUANYUAN LI ◽  
XIAOMIN REN ◽  
KAN JIANG
Keyword(s):  
Complex Networks ◽  
Geodesic Distance ◽  
Average Distance ◽  
Weighted Average ◽  
Similar Measure ◽  
Important Index ◽  
Self Similar

The average geodesic distance is an important index in the study of complex networks. In this paper, we investigate the weighted average distance of Pentadendrite fractal and Pentadendrite networks. To provide the formula, we use the integral of geodesic distance in terms of self-similar measure with respect to the weighted vector.

scholarly journals Cooperating the BDS, GPS, GLONASS and strong-motion observations for real-time deformation monitoring

2017 ◽  
Vol 209 (3) ◽  
pp. 1408-1417 ◽  
Author(s):  
Rui Tu ◽  
Jinhai Liu ◽  
Cuixian Lu ◽  
Rui Zhang ◽  
Pengfei Zhang ◽  
...  
Keyword(s):  
Real Time ◽  
Strong Motion ◽  
Deformation Monitoring ◽  
Time Deformation

Simplification algorithm of denture point cloud based on feature preserving

2021 ◽  
pp. 1-14
Author(s):  
Shigang Wang ◽  
Shuai Peng ◽  
Jiawen He
Keyword(s):  
Point Cloud ◽  
Clustering Algorithm ◽  
Characteristic Point ◽  
Cloud Model ◽  
Average Distance ◽  
Normal Vector ◽  
Sampling Point ◽  
Characteristic Region ◽  
K Value ◽  
Feature Preserving

Due to the point cloud of oral scan denture has a large amount of data and redundant points. A point cloud simplification algorithm based on feature preserving is proposed to solve the problem that the feature preserving is incomplete when processing point cloud data and cavities occur in relatively flat regions. Firstly, the algorithm uses kd-tree to construct the point cloud spatial topological to search the k-Neighborhood of the sampling point. On the basis of that to calculate the curvature of each point, the angle between the normal vector, the distance from the point to the neighborhood centroid, as well as the standard deviation and the average distance from the point to the neighborhood on this basis, therefore, the detailed features of point cloud can be extracted by multi-feature extraction and threshold determination. For the non-characteristic region, the non-characteristic point cloud is spatially divided through Octree to obtain the K-value of K-means clustering algorithm and the initial clustering center point. The simplified results of non-characteristic regions are obtained after further subdivision. Finally, the extracted detail features and the reduced result of non-featured region will be merged to obtain the final simplification result. The experimental results show that the algorithm can retain the characteristic information of point cloud model better, and effectively avoid the phenomenon of holes in the simplification process. The simplified results have better smoothness, simplicity and precision, and are of high practical value.

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