A Real-Time Haptics-Based Deformable Model for Virtual Prototyping and Simulations

Author(s):  
Jinling Wang ◽  
Wen F. Lu

Virtual reality technology plays an important role in the fields of product design, computer animation, medical simulation, cloth motion, and many others. Especially with the emergence of haptics technology, virtual simulation system provides an intuitive way of human and computer interaction, which allows user to feel and touch the virtual environment. For a real-time simulation system, a physically based deformable model including complex material properties with a high resolution is required. However, such deformable model hardly satisfies the update rate of interactive haptic rendering that exceeds 1 kHz. To tackle this challenge, a real-time volumetric model with haptic feedback is developed in this paper. This model, named as Adaptive S-chain model, extends the S-chain model and integrates the energy-based wave propagation method by the proposed adaptive re-mesh method to achieve realistic graphic and haptic deformation results. The implemented results show that the nonlinear, heterogeneous, anisotropic, shape retaining material properties and large range deformation are well modeled. An accurate force feedback is generated by the proposed Adaptive S-chain model in case study which is quite close to the experiment data.

Displays ◽  
1994 ◽  
Vol 15 (3) ◽  
pp. 149-155 ◽  
Author(s):  
Annie Luciani ◽  
Claude Cadoz ◽  
Jean Loup Florens

Machines ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 76
Author(s):  
Sébastien Timmermans ◽  
Bruno Dehez ◽  
Paul Fisette

A piano key prototype actuated by a custom-made linear actuator is proposed to enhance the touch of digital pianos by reproducing the force feedback of an acoustic piano action. This paper presents the design and the validation of the haptic device. The approach exploits a multibody model to compute the action dynamics and the corresponding force on the key in real time. More specifically, a grand piano model that includes the five action bodies, its geometry and the specific force laws, is computed in the haptic device. A presizing step along with Finite Element Method (FEM) analysis produced an especially made actuator satisfying the design requirements, in particular the highly dynamic nature of the force to be transmitted. Force peaks, up to 50 (N) in less than 20 (ms), are reachable with low power consumption. Compared to previous solutions: (i) the key physical characteristics are preserved; (ii) the feedback is based on a real-time multibody model that is easily configurable and interchangeable; (iii) an experimental validation of the actuator within the prototype is developed and demonstrates its feasibility. The results confirm that the voice coil can produce suitable haptic feedback. In particular, rendering a grand piano action within the device shows promising haptic force profiles.


2011 ◽  
Vol 20 (4) ◽  
pp. 289-308 ◽  
Author(s):  
Suvranu De ◽  
Dhannanjay Deo ◽  
Ganesh Sankaranarayanan ◽  
Venkata S. Arikatla

While an update rate of 30 Hz is considered adequate for real-time graphics, a much higher update rate of about 1 kHz is necessary for haptics. Physics-based modeling of deformable objects, especially when large nonlinear deformations and complex nonlinear material properties are involved, at these very high rates is one of the most challenging tasks in the development of real-time simulation systems. While some specialized solutions exist, there is no general solution for arbitrary nonlinearities. In this work we present PhyNNeSS—a Physics-driven Neural Networks-based Simulation System—to address this long-standing technical challenge. The first step is an offline precomputation step in which a database is generated by applying carefully prescribed displacements to each node of the finite element models of the deformable objects. In the next step, the data is condensed into a set of coefficients describing neurons of a Radial Basis Function Network (RBFN). During real-time computation, these neural networks are used to reconstruct the deformation fields as well as the interaction forces. We present realistic simulation examples from interactive surgical simulation with real-time force feedback. As an example, we have developed a deformable human stomach model and a Penrose drain model used in the Fundamentals of Laparoscopic Surgery (FLS) training tool box. A unique computational modeling system has been developed that is capable of simulating the response of nonlinear deformable objects in real time. The method distinguishes itself from previous efforts in that a systematic physics-based precomputational step allows training of neural networks which may be used in real-time simulations. We show, through careful error analysis, that the scheme is scalable, with the accuracy being controlled by the number of neurons used in the simulation. PhyNNeSS has been integrated into SoFMIS (Software Framework for Multimodal Interactive Simulation) for general use.


2013 ◽  
Vol 336-338 ◽  
pp. 1366-1369
Author(s):  
Jong Seok Oh ◽  
Seung Bok Choi

In this paper, a new volumetric deformable model that is suitable for real-time haptic rendering is proposed. Haptic rendering is the process of calculating and generating repulsive force in response to user interactions with virtual objects. In order to embody a deformable object into virtual space, a volumetric deformable object represented by a shape-retaining chain linked (S-chain) model is adopted. S-chain model allows for fast and realistic deformation of elastic objects. The classical S-chain model was satisfactory but there was still room for improvement. In order to improve this limitation, we propose an advanced S-chain algorithm which can be compatible with classical S-chain model.


2014 ◽  
Vol 536-537 ◽  
pp. 900-906
Author(s):  
Yan Hong Fang ◽  
Bin Wu ◽  
Zheng Yi Yang

To improve the precision and real-time of the virtual liver surgery simulation system with haptic feedback, a novel deformation modelling based on wave equation and spherical harmonic is proposed. Continuous changed liver models were mapped into a common reference system in which corresponding coefficients of spherical harmonic were compared with method of principal components analysis and force feedback were calculated by simplified deformation wave equation. Moreover, system structure design, fast collision detection and real-time feedback operation are also discussed in detail. Experimental platform of virtual liver surgery was established based on vizard 4.0 and Sensable-phantom® desktopTM. Experiment results show that the system can provide a stable force to the human operator and which satisfy the requirement of real-time performance. Establishing a simple and lifelike physics deformation model and a precise and rapid collision detection algorithm favors the performance improvement of the virtual liver surgery simulation system.


Author(s):  
Jinling Wang ◽  
Wen F. Lu

In this paper, a haptic modeling and simulation system is developed to assist handheld product design. With haptic feedback, users could create, interact and evaluate the virtual product directly and intuitively without producing the physical prototype. This saves the cost and reduces time-to-market, which is especially meaningful for the rapidly changing handheld mobile devices. To provide a comfortable and accurate operation, a virtual vibration actuator is devised to add into the touch screen. Unlike the previous research that mainly focuses on the design of the product shape, the proposed system also models the interaction between the user (finger) or tool (pen) and handheld device (button/screen). To obtain realistic simulation and replace the physical prototype, the complex shape and deformation of the finger are considered when calculating the feedback force. A computational efficient collision detection method for complex shape objects is proposed to tackle the challenge of a high update rate of more than 1 kHz for real-time realistic haptic rendering. Moreover, the proposed system incorporates the haptic modeling of vibration interaction and menu interface design into the product design simulation system. A case study of handheld device design is used to illustrate the proposed system.


Author(s):  
Fei Zheng ◽  
WenFeng Lu ◽  
Yoke San Wong ◽  
Kelvin Weng Chiong Foong

Dental bone drilling is an inexact and often a blind art. Dentist risks damaging the invisible tooth roots, nerves and critical dental structures like mandibular canal and maxillary sinus. This paper presents a haptics-based jawbone drilling simulator for novice surgeons. Through the real-time training of tactile sensations based on patient-specific data, improved outcomes and faster procedures can be provided. Previously developed drilling simulators usually adopt penalty-based contact force models and often consider only spherical-shaped drill bits for simplicity and computational efficiency. In contrast, our simulator is equipped with a more precise force model, adapted from the Voxmap-PointShell (VPS) method to capture the essential features of the drilling procedure. In addition, the proposed force model can accommodate various shapes of drill bits. To achieve better anatomical accuracy, our oral model has been reconstructed from Cone Beam CT, using voxel-based method. To enhance the real-time response, the parallel computing power of Graphics Processing Units is exploited through extra efforts for data structure design, algorithms parallelization, and graphic memory utilization. Preliminary results show that the developed system can produce appropriate force feedback at different tissue layers.


2011 ◽  
Vol 130-134 ◽  
pp. 2684-2687 ◽  
Author(s):  
Kai Xu ◽  
Yan Lv ◽  
Guang Jin

Semi-physical simulation of attitude control system is the more synthetically test and verify for designing of small satellite control system. It is an important means of small satellite development. However, the results of current semi-physical simulation system have a lot of non-intuitive. Compare with the actual environment, the simulation environment still has striking disparity. So the shortcomings affect precision of simulation. Based on the virtual display technology, the group semi-physical simulation system has been constructed for attitude control of small satellite due to the combination with xPC real-time environment, the simulation computer, high-precision single-axis air-bearing turntable, reaction wheel, air thrust device, fiber gyroscopes, sensors synchronizer, power subsystem and wireless devices virtual display computer etc. Semi-physical simulation achieved the visual simulation in orbit and tracked new information of virtual environment of space into real-time simulation computer. Simulation results show that the simulation system for real-time attitude and orbit position of small satellite semi-physical simulation has an excellent display effect. At the same time, Real-time transfuse of orbit information provides a more accurate space environment simulation. The simulation system of small satellite attitude control to design and evaluate the more direct and convenient.


2013 ◽  
Vol 22 (06) ◽  
pp. 1360019
Author(s):  
DAMON BLANCHETTE ◽  
EMMANUEL AGU

Spectral rendering, or the synthesis of images by taking into account the constituent wavelengths of white light, enables the rendering of iridescent colors caused by phenomena such as dispersion, diffraction, interference and scattering. Caustics, the focusing and defocusing of light through a refractive medium, can be interpreted as a special case of dispersion where all the wavelengths travel along the same paths. In this paper we extend Adaptive Caustic Mapping (ACM), a previously proposed caustics mapping algorithm, to handle physically-based dispersion. Because ACM can display caustics in real-time, it is amenable to extension to handle the more general case of dispersion. We also present a novel algorithm for filling in the gaps that occur due to discrete sampling of the spectrum. Our proposed method runs in screen-space, and is fast enough to display plausible dispersion phenomena at real-time and interactive frame rates.


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