Generating haptic texture using solid noise

Texture enhances haptic interaction by providing unique, distinguishable, and versatile surfaces. In computer haptics, texture can render environments more realistic and provide useful information. In this paper, an algorithm is proposed for virtual texture simulation by using solid noise, where only a few parameters need to be altered to generate a range of realistic and diverse textures by reproducing different frequencies similar to that of real vibrational signals in a virtual environment. The proposed method can capture the textural effect in a haptic simulation while retaining a simple overall geometry and stable update rate. This method also allows the user to change the texture at runtime and can be easily incorporated into any existing code and used in any traditional haptic device without affecting overall haptic-rendering performance. Moreover, the solid noise texture is independent of object geometry and can be applied to any shape without additional computations. We conducted a human-subject study to evaluate the recognition accuracy for each generated haptic texture as well as its realism and correspondence to real texture. The results indicated the high performance of the method and its ability to generate haptic textures with a very high recognition rate that were highly realistic.     

Virtual DesignWorks—designing 3D CAD models via haptic interaction

Haptic devices (force feedback interfaces) show great promise for use in the design of CAD models. However, current haptic systems are used primarily to verify rather than to interact with CAD systems to design a model.The paper discusses a haptic-based CAD system—Virtual DesignWorks. It is the world's first haptic application for the design of CAD models based on component technology (COM+). With haptic devices, the system allows engineers, in virtual space, to directly touch a native B-Rep CAD model, and deform it by pushing, pulling and dragging its surfaces in a natural three-dimensional environment. Virtual DesignWorks adopts the novel COM-based haptic model, which demonstrates significant advantages compared to the traditional haptic models. Force feedback gives designers the greatest flexibility for the design of complex surfaces, and haptics has the potential to become a critical interface for design applications.     

Toward realistic haptic rendering of surface textures

New sophisticated haptic-rendering algorithms let users experience virtual objects through touch. We systematically investigate the unrealistic behavior of virtual haptic textures. The emerging science of haptic rendering consists of delivering properties of physical objects through the sense of touch. Owing to the recent development of sophisticated haptic-rendering algorithms, users can now experience virtual objects through touch in many exciting applications, including surgical simulations, virtual prototyping, and data perceptualization. Haptics holds great promise to enrich the sensory attributes of virtual objects that these systems can produce. One area that has received increasing attention in the haptics community is haptic texture rendering, the goal of which is to introduce micro-geometry-scale features on object surfaces. Haptic objects rendered without textures usually feel smooth, and sometimes slippery. Appropriate haptic textures superimposed on haptic objects enhance an object's realism.     

Real-time haptic interaction with RGBD video streams

Video interaction is a common way of communication in cyberspace. It can become more immersive by incorporating haptic modality. Using commonly available depth sensing controllers like Microsoft Kinect, information about the depth of a scene can be captured in real-time together with the video. In this paper, we present a method for real-time haptic interaction with videos containing depth data. Forces are computed based on the depth information. Spatial and temporal filtering of the depth stream is used to provide stability of force feedback delivered to the haptic device. Fast collision detection ensures the proposed approach to be used in real-time. We present an analysis of various factors that affect algorithm performance. The usefulness of the approach is illustrated by highlighting possible application scenarios.     

Energy-based control of a haptic device using brakes.

This paper proposes an energy-based control method of a haptic device with electric brakes. Unsmooth motion is frequently observed in a haptic system using brakes during a wall-following task. Since it is generally known that a haptic system using brakes is passive due to brake's characteristics, its energy behavior has seldom been investigated. However, force distribution at the end effector reveals that the unsmooth motion of a haptic system using brakes represents active behavior of the system in the specific direction. A force control scheme is proposed that computes the gain for smooth motion by considering the energy behavior of a system. Experiments show that smooth wall following is possible with a proposed force control scheme.     

Bridging the HASM: An OWL ontology for modeling the information pathways in haptic interfaces software

Haptics technology has received enormous attention to enhance human computer interaction. The last decade has witnessed a rapid progress in haptic application software development due to the fact that the underlying technology has become mature and has opened up novel research areas. In an attempt to organize the path between cause and effect we envision a need for a standard for haptic application software modeling. In order for the software to better enhance the tactile information sensation, flow and perception and also make interaction between humans and haptics more efficient and natural, we need a formal representation of the haptics domain. This article proposes the use of HASM, a haptic applications software modeling ontology to formally model the haptics domain in order to be used during the specifications and design phases of developing software applications for haptic interfaces. The presented ontology captures the existing knowledge in haptics domain, using OWL, and defines the pathways that the haptic information follows between the human and the machine haptic system, using SWRL rules. The haptic ontology that has been developed will be used as a basis to design effective user interfaces and assist the development of software modeling for haptic devices. A case study is demonstrating how this haptic ontology can be used to design a software model that analyzes the perception of a haptic property of an object by interacting with a haptic device.     

Design and evaluation of haptic effects for use in a computer desktop for the physically disabled

The human–computer interface remains a mostly visual environment with little or no haptic interaction. While haptics is finding inroads in specialized areas such as surgery, gaming, and robotics, there has been little work to bring haptics to the computer desktop, which is largely dominated today by the GUI/mouse relationship. The mouse as an input device, however, poses many challenges for users with physical disabilities, and it is believed that a haptically enhanced interface could have significant impact assisting in target selection. This paper presents a study intended to evaluate haptic effects used with a force feedback mouse on a computer desktop and a prediction algorithm designed to focus those effects on the desired target. Results of the experiment were partially successful and indicated future directions for improvement. The paper introduces the proposed framework and presents experimental results from targeting tasks using differing haptic effects with a group of physically disabled users.     

Enabling design and interactive selection of haptic modes

The ever increasing size and complexity of volumetric data in a wide range of disciplines makes it useful to augment volume visualization tools with alternative modalities. Studies have shown that introducing haptics can significantly increase both exploration speed and precision. It is also capable of conveying material properties of data and thus has great potential to improve user performance in volume data exploration. In this paper we describe how recent advances in volume haptics can be used to build haptic modes—building blocks for haptic schemes. These modes have been used as base components of a toolkit allowing for more efficient development of haptic prototypes and applications. This toolkit allows interactive construction, configuration and fine-tuning of both visual and haptic representations of the data. The technology is also used in a pilot study to determine the most important issues and aspects in haptic volume data interaction and exploration, and how the use of haptic modes can facilitate the implementation of effective haptic schemes.     

Stable adaptive algorithm for Six Degrees-of-Freedom haptic rendering in a dynamic environment

Recently, physically-based simulations with haptics interaction attracted many researchers. In this paper, we propose an adaptive Six Degrees-of-Freedom (6-DOF) haptic rendering algorithm based on virtual coupling, which can automatically adjust virtual coupling parameters according to mass values of the simulated virtual tools. The algorithm can overcome the virtual tool displacement problem caused by the large mass values of the virtual tool and can provide stable force/torque display. The force/torque magnitude is saturated to the maximum force/torque values of the haptic device automatically. The implemented algorithm is tested on the simple and complex standard benchmarks. The experimental results confirm that the proposed adaptive 6-DOF haptic rendering algorithm displays good stability and accuracy for haptic rendering of dynamic virtual objects with mass values.     

SPH haptic interaction with multiple-fluid simulation

Physics-based fluid interaction plays an important role in computer animation, with wide applications in virtual reality, computer games, digital entertainment, etc. For example, in virtual reality education and games, we often need fluid interactions like acting as an alchemist to create a potion by stirring fluid in a crucible. The traditional input devices such as a mouse and keyboard can basically input 2D information without feedback. In recent years, the continuous development of haptic device not only can achieve six degrees-of-freedom input, but also can calculate the force in virtual scenes and feedback to the user to make a better virtual experience. How to use haptic device in different kinds of virtual fluid scenarios to provide better experience is an important issue in the field of virtual reality. On the other hand, the researches on multiple-fluid interaction especially based on smoothed particle hydrodynamics (SPH) method are very lacking. Therefore, we study the key techniques of haptic interaction with SPH multiple-fluid to compensate this defect in computer graphics community. Different from the single-phase flow, interaction with multiple-fluid flow has difficulties in the realization of properties of different phases. After adding the multiple-fluid simulation, it is also important to keep haptic interaction real time. Our research is based on the mixture model. We guarantee the authenticity of multiple-fluid mixing effect while changing the drift velocity solver to improve efficiency. We employ a unified particle model to achieve rigid body–liquid coupling, and use FIR filter to smooth feedback force to the haptic device. Our novel multiple-fluid haptic simulation can provide an interactive experience for mixing liquid in virtual reality.     

A non‐smooth lower bound on ν

A non‐smooth optimization technique to directly compute a lower bound on the skew structured singular value ν is developed. As corroborated by several real‐world challenging applications, the proposed technique can provide tighter lower bounds when compared with currently available techniques. Moreover, in many cases, the determined lower bound equals the true value of ν. Thanks to the efficiency of the non‐smooth technique, the algorithm can be applied to problems involving even a significant number of uncertain parameters. Another appealing feature of the proposed non‐smooth approach is that the dimension of repeated scalar uncertainties in the overall structured uncertainty matrix has little impact on the computational time. The technique can be used to compute a lower bound on the structured singular value μ as well. Copyright © 2012 John Wiley & Sons, Ltd.     

Neuro-cognitively inspired haptic user interfaces

Haptic systems and devices are a recent addition to multimodal systems. These devices have widespread applications such as surgical simulations, medical and procedural training, scientific visualizations, assistive and rehabilitative devices for individuals who have physical or neurological impediments and assistive devices for individuals who are blind. While the potential of haptics in natural human machine interaction is undisputable, the realization of such means is still a long way ahead. There are considerable research challenges to development of natural haptic interfaces. The study of human tactile abilities is a recent endeavor and many of the available systems still do not incorporate the domain knowledge of psychophysics, biomechanics and neurological elements of haptic perception. Development of smart and effective haptic interfaces and devices requires extensive studies that link perceptual phenomena with measurable parameters and incorporation of such domain knowledge in the engineering of haptic interfaces. This paper presents design, development and usability testing of a neuro-cognitively inspired haptic user interface for individuals who are blind. The proposed system design is inspired by neuro-cognitive basis of haptic perception and incorporates the computational aspects and requirements of multimodal information processing system. Usability testing of the system suggests that a biologically inspired haptic user interfaces may form a powerful paradigm for haptic user interface design.

Perception-based lossy haptic compression considerations for velocity-based interactions

The ability of technology to transmit multi-media is very dependent on compression techniques. In particular lossy compression has been used in image compression (jpeg) audio compression (mp3) and video compression (mpg) to allow the transmission of audio and video over broadband network connections. Recently the sense of touch or haptics is becoming more important with its addition in computer games or in cruder applications such as vibrations in a cell phone. As haptic technology improves the ability to transmit compressed force sensations becomes more critical. Most lossy audio and visual compression techniques rely on the lack of sensitivity in humans to pick up detailed information in certain scenarios. Similarly limitations in the sensitivity of human touch could be exploited to create haptic models with much less detail and thus requiring smaller bandwidth. The focus of this paper is on the force thresholds of the human haptic system that can be used in a psychophysically motivated lossy haptic (force) compression technique. Most of the research in this field has measured the just noticeable difference (JND) of the human haptic system with a human user in static interaction with a stationary rigid object. In this paper our focus involves cases where the human user or the object are in relative motion. An example of such an application would be the haptic rendering of the user’s hand in contact with of a high-viscous material or interacting with a highly deformable object. Thus an approach is presented to measure the force threshold based on the velocity of the user’s hand motion. Two experiments are conducted to detect the absolute force threshold (AFT) of the human haptic system using methodologies from the field of psychophysics. The AFTs are detected for three different ranges of velocity of the user’s hand motion. This study implies that when a user’s hand is in motion fewer haptic details are required to be stored calculated or transmitted. Finally the implications of this study on a more complete future study will be discussed.

Desktop haptic virtual assembly using physically based modelling

This research investigates the feasibility of using a desktop haptic virtual environment as a design tool for evaluating assembly operations. Bringing virtual reality characteristics to the desktop, such as stereo vision, further promotes the use of this technology into the every day engineering design process. In creating such a system, the affordability and availability of hardware/software tools is taken into consideration. The resulting application combines several software packages including VR Juggler, open dynamics engine (ODE)/open physics abstraction layer (OPAL), OpenHaptics, and OpenGL/GLM/GLUT libraries to explore the benefits and limitations of combining haptics with physically based modelling. The equipment used to display stereo graphics includes a Stereographics emitter, Crystal Eyes shutter glasses, and a high refresh rate CRT Monitor. One or two-handed force feedback is obtained from various PHANTOM haptic devices from SensAble Technologies Inc. The application’s ability to handle complex part interactions is tested using two different computer systems, which approximate the higher and lower end of a typical engineer’s workstation. Different test scenarios are analyzed and results presented.     

Touch-enabled haptic modeling of deformable multi-resolution surfaces

Currently, interactive data exploration in virtual environments is mainly focused on vision-based and non-contact sensory channels such as visual/auditory displays. The lack of tactile sensation in virtual environments removes an important source of information to be delivered to the users. In this paper, we propose the touch-enabled haptic modeling of deformable multi-resolution surfaces in real time. The 6-DOF haptic manipulation is based on a dynamic model of Loop surfaces, where the dynamic parameters are computed easily without subdividing the control mesh recursively. A local deforming scheme is developed to approximate the solution of the dynamics equations, thus the order of the linear equations is reduced greatly. During each of the haptic interaction loop, the contact point is traced and reflected to the rendering of updated graphics and haptics. The sense of touch against the deforming surface is calculated according to the surface properties and the damping-spring force profile. Our haptic system supports the dynamic modeling of deformable Loop surfaces intuitively through the touch-enabled interactive manipulation.     

Whole-hand kinesthetic feedback and haptic perception in dextrous virtual manipulation

One of the key requirements for a Virtual Reality system is the multimodal, real-time interaction between the human operator and a computer simulated and animated environment. This paper investigates problems related particularly to the haptic interaction between the human operator and a virtual environment. The work presented here focuses on two issues: 1) the synthesis of whole-hand kinesthetic feedback, based on the application of forces (torques) on individual phalanges (joints) of the human hand, and 2) the experimental evaluation of this haptic feedback system, in terms of human haptic perception of virtual physical properties (such as the weight of a virtual manipulated object), using psychophysical methods. The proposed kinesthetic feedback methodology is based on the solution of a generalized force distribution problem for the human hand during virtual manipulation tasks. The solution is computationally efficient and has been experimentally implemented using an exoskeleton force-feedback glove. A series of experiments is reported concerning the perception of weight of manipulated virtual objects and the obtained results demonstrate the feasibility of the concept. Issues related to the use of sensory substitution techniques for the application of haptic feedback on the human hand are also discussed.     

Design and validation of a complete haptic system for manipulative tasks

The present work deals with the design, implementation and assessment of a new haptic system specifically conceived for manipulative tasks in virtual environments. Such a system was designed by taking into account specific issues related to fine manipulation, such as multipoint haptics, coherence, transparency and physical representation. The haptic system described herein is integrated with a virtual environment engine for the simulation of multifinger manipulation. A preliminary evaluation of the system was conducted by comparing human performance in the manipulation of virtual objects with respect to real objects, according to the data available in the literature. The experiments confirm how the most relevant relationships among physiological and physical parameters involved in manipulation are also preserved during virtual manipulation. However, an in-depth analysis of the results shows that simulation parameters affect the level of force control during virtual manipulation and the quality of the perceived force feedback.     

Observability and Controllability Analysis for Micro‐Positioning Stage Described by Sandwich Model with Hysteresis

In this paper, an approach for analyzing the observability and controllability of micro‐positioning stage with piezoelectric actuator described by sandwich model with hysteresis is proposed. As hysteresis inherent in piezoelectric actuator is a non‐smooth nonlinear function with multi‐valued mapping, the positioning system is also a non‐smooth dynamic system. The Prandtl‐Ishlinksii (PI) submodel is employed to describe the characteristic of hysteresis embedded in the sandwich system. A linearization method based on non‐smooth optimization is proposed to derive a generalized linearized state‐space function to approximate the non‐smooth sandwich systems within a bounded region around the equilibrium points the system works at. Then, both observability and controllability matrices are constructed and the methods to analyze the observability as well as the controllability of sandwich system with hysteresis are derived. Finally, a simulation example and an application of the proposed method to a micro‐positioning stage with piezoactuator are presented to validate the proposed method.     

Image‐inspired haptic interaction

We add new modality to image‐based visualization by converting ordinary photos into tangible images, which can be then haptically rendered. This is performed by interactive sketching haptic models on the photos so that the models match the image parts, which will become tangible. In contrast to common geometric modelling, we define the haptic models in a three‐dimensional haptic modelling space distorted by the central projection. Analytic FRep functions (variants of implicit functions) are mostly used for defining the haptic models. The tangible images thus created can realistically simulate some actual three‐dimensional scenes by implementing the principle “What You See Is What You Touch” while in fact still be 2D images. Copyright © 2015 John Wiley & Sons, Ltd.     

Priority-based haptic event filtering for transmission and error control in networked virtual environments

A data filtering scheme is proposed for transmission and error control of haptic events in haptic-based network virtual environments; this scheme is called as priority-based haptic event filtering. Because a high update rate of approximately 1 kHz is required for haptic rendering, sophisticated transmission rate control and reduction schemes are necessary for the haptic events. Although existing schemes can reduce the transmission rate without any perception impairment, they are very sensitive to packet losses. In this paper, we prioritize the haptic events according to the delay and loss effects. Utilizing the proposed haptic event prioritization, the proposed filtering scheme adapts the transmission rate and updates the predicted loss rate according to the current network state. Our simulation and experiment results confirm that the proposed scheme can effectively select important haptic events and guarantee an improved haptic interaction quality over a bandwidth-limited lossy network than existing transmission schemes tailored for networked haptics.