Haptic Design Research Articles

Design and Analysis of a Haptic Device Design for Large and Fast Movements

Haptic devices tend to be kept small as it is easier to achieve a large change of stiffness with a low associated apparent mass. If large movements are required there is a usually a reduction in the quality of the haptic sensations which can be displayed. The typical measure of haptic device performance is impedance-width (z-width) but this does not account for actuator saturation, usable workspace or the ability to do rapid movements. This paper presents the analysis and evaluation of a haptic device design, utilizing a variant of redundant kinematics, sometimes referred to as a macro-micro configuration, intended to allow large and fast movements without loss of impedance-width. A brief mathematical analysis of the design constraints is given and a prototype system is described where the effects of different elements of the control scheme can be examined to better understand the potential benefits and trade-offs in the design. Finally, the performance of the system is evaluated using a Fitts’ Law test and found to compare favourably with similar evaluations of smaller workspace devices.

Introduction and overview

SummaryPCO remains the commonest complication of cataract surgery and is a particular problem with presbyopia correcting multifocal IOLs which are more sensitive to mild PCO and it remains the barrier to a truly accommodating IOL. This presentation reviews the current clinical status of PCO prevention and in particular the contribution of IOL material and design. Hydrophobic materials appear to induce less PCO than hydrophilic polymers and the reasons for this will be discussed. Square edge profile IOLs have reduced the incidence of PCO but delay rather than cure the problem, edge profile quality is however is very variable and this has clinical implications. Haptic design also affects PCO performance. New ‘open bag’ IOL designs appear to offer a significant improvement in PCO prevention.

Rendered and Characterized Closed-Loop Accuracy of Impedance-Type Haptic Displays.

Impedance-type kinesthetic haptic displays aim to render arbitrary desired dynamics to a human operator using force feedback. To render realistic virtual environments, the difference between desired and rendered dynamics must be small. In this paper, we analyze the closed-loop dynamics of haptic displays for three common virtual environments: a spring, a damper, and a spring-damper, including the effects of time delay and low-pass filtering. Using a linear model, we identify important parameters for the rendered dynamics in terms of effective impedances, a conceptual tool that decomposes the displays closed-loop impedance into components with physical analogs. Our results establish bandwidth limits for rendering effective stiffness and damping. The effective stiffness bandwidth is limited by the virtual stiffness and device mass, and the effective damping bandwidth is limited by the cut-off frequency of the low-pass filter which filters the device velocity estimate. We show that a general system impedance can be characterized by a mass, damper, and spring optimally by the solution to a convex optimization problem, and we present a quantitative metric, the Average Distortion Error (ADE), to describe the fidelity of this model. Time delay has no significant effect on characterized stiffness, and reduces characterized damping by the product of virtual stiffness and total time delay. Reducing the low-pass filter cut-off frequency reduces the characterized damping. Experimental data gathered with a Phantom Premium 1.5 validates the theoretical analysis. We also conducted human user experiments to investigate the effects of time delay and low-pass filtering on perceived stiffness and damping. Similar to the characterized dynamics results, we observed no significant effect of time delay on perceived stiffness, and increasing time delay resulted in reduced perceived damping. Lower filter cut-off frequencies resulted in lower perceived damping. This work informs haptic display design by presenting how closed-loop behavior changes with key parameters.

Haptic feedback using an all-organic electroactive polymer composite

The development of mobile haptics and multimodal designs has been strongly limited by the lack of enabling actuator technologies. This paper presents the properties of an electrostrive actuator technology for haptic feedback. By carefully tailoring material properties and actuator designing which can be integrating in devices, this technology should provide a realistic possibility of haptic design with considerable latitude. Haptic characteristics are described and realized and their impact on haptic design is discussed.

53.3: Invited Paper: Creating a Compelling Touch Experience

Touchscreen car infotainment systems now offer a larger variety and a more complex set of use cases than ever. Haptics have the potential to improve safety, utility, and user experience of these touch‐based systems. This paper will cover some haptic design considerations and discuss how to create compelling haptic experiences in a touchscreen infotainment system.

A haptic keypad design with a novel interactive haptic feedback method

This study creates a haptic keypad design with a novel interactive haptic feedback method. The design uses thin piezoelectric actuators to simulate actual rubber-dome keyboard typing experiences. Traditional haptic keyboard designs only consider functional requirements or functional structures. This study considers both user behaviours and keyboard behaviours to improve haptic feedback. The design uses minimum keystroke durations for buckling and restitution events for normal key presses, and minimum hold-down durations between buckling and restitution events for continuous key presses, to simulate actual rubber-dome keyboard typing experiences. Usability study results show that the design creates realistic haptic feedback that users rate equivalent to haptic feedback on traditional rubber-dome keyboards, and better than haptic feedback on other keypads, keyboards, or electronic devices that are currently on the market. The design can also be used to create new types of computers, tablets, or cell phones that create more realistic haptic feedback.

Feel Effects

Despite a long history of use in communication, haptic feedback is a relatively new addition to the toolbox of special effects. Unlike artists who use sound or vision, haptic designers cannot simply access libraries of effects that map cleanly to media content, and they lack even guiding principles for creating such effects. In this article, we make progress toward both capabilities: we generate a foundational library of usable haptic vocabulary and do so with a methodology that allows ongoing additions to the library in a principled and effective way. We define a feel effect as an explicit pairing between a meaningful linguistic phrase and a rendered haptic pattern. Our initial experiment demonstrates that users who have only their intrinsic language capacities, and no haptic expertise, can generate a core set of feel effects that lend themselves via semantic inference to the design of additional effects. The resulting collection of more than 40 effects covers a wide range of situations (including precipitation, animal locomotion, striking, and pulsating events) and is empirically shown to produce the named sensation for the majority of our test users in a second experiment. Our experiments demonstrate a unique and systematic approach to designing a vocabulary of haptic sensations that are related in both the semantic and parametric spaces.

Influence of intraocular lens haptic design on refractive error

To assess the influence of intraocular (IOL) haptic design on the refraction prediction error in patients having cataract surgery. Private practice. Comparative case series. Corneal power and axial length were measured with the same devices in eyes with a 3-piece Acrysof IOL and eyes with a 1-piece Acrysof IOL and were entered into the Haigis, Hoffer Q, Holladay 1, and SRK/T formulas. The median absolute error and mean absolute error in refraction prediction (ie, difference between expected refraction and actual refraction) were assessed 1month postoperatively. The study evaluated 110 eyes with the 3-piece IOL and 84 eyes with the 1-piece IOL. With all formulas, the median absolute error was lower with the 3-piece IOL. It ranged between 0.15 diopter (D) (Haigis and Holladay 1) and 0.19 D (SRK/T) with the 3-piece IOL and between 0.23 D (Haigis) and 0.30 D (SRK/T) with the 1-piece IOL. With all formulas, a higher percentage of eyes with the 3-piece IOL were within ±0.25 D and ±0.50 D of the target refraction. Three-piece IOLs may yield better refractive outcomes than 1-piece IOLs. A possible reason is that once the early forward IOL shift previously observed with the 3-piece design occurs because of the haptic-compression force decay typical of these IOLs, the rigid haptics of 3-piece IOLs still exert more pressure against the capsular bag than the haptics of 1-piece IOLs. Therefore, 3-piece IOLs may better resist subsequent capsule contraction and provide a more predictable effective lens position. Dr. Hoffer receives royalties for his book IOL Power, Slack, Inc., and formula royalties from all manufacturers using the Hoffer Q formula. No other author has a financial or proprietary interest in any material or method mentioned.

Velocity estimation algorithms for audio-haptic simulations involving stick-slip.

With real-time models of friction that take velocity as input, accuracy depends in great part on adequately estimating velocity from position measurements. This process can be sensitive to noise, especially at high sampling rates. In audio-haptic acoustic simulations, often characterized by friction-induced, relaxation-type stick-slip oscillations, this gives a gritty, dry haptic feel and a raspy, unnatural sound. Numerous techniques have been proposed, but each depend on tuning parameters so that they may offer a good trade-off between delay and noise rejection. In an effort to compare fairly, each of thirteen methods considered in the present study was automatically optimized and evaluated; finally a subset of these were compared subjectively. Results suggest that no one method is ideal for all gain levels, though the best general performance was found by using a sliding-mode differentiator as input to a Kalman integrator. An additional conclusion is that estimators do not approach the quality available in physical velocity transduction, and therefore such sensors should be considered in haptic device design.

Visual and optical performance of diffractive multifocal intraocular lenses with different haptic designs: 6 month follow-up

PurposeTo evaluate and compare the visual acuity outcomes and optical performances of eyes implanted with two diffractive multifocal intraocular lens (IOL) models with either a plate haptic design or a modified-C design.MethodsThis retrospective study comprised cataract patients who were implanted with either a plate haptic multifocal IOL model (AcrivaUD Reviol BB MFM 611 [VSY Biotechnology, Amsterdam, the Netherlands], group 1) or a modified-C haptic multifocal IOL model (AcrivaUD Reviol BB MF 613 [VSY Biotechnology, Amsterdam, the Netherlands], group 2) between June 2012 and May 2013. The 6 month postoperative visual acuity, refraction, defocus curve, contrast sensitivity, and wave-front aberration were evaluated and compared between these eyes, using different IOL models.ResultsOne hundred fifty-eight eyes of 107 patients were included in this study. Significant improvement in visual acuities and refraction was found in both groups after cataract surgery (P<0.01). The visual acuity and contrast sensitivity were statistically better in group 1 than in group 2 (P<0.01). No statistically significant difference in the corneal higher-order aberrations was found between the two groups (P>0.05). However, the ocular higher-order aberrations in group 2 were significantly greater than in group 1 (P<0.05).ConclusionAt 6 months postoperatively, both AcrivaUD Reviol BB MFM 611 IOL and AcrivaUD Reviol BB MF 613 IOL achieved excellent visual and refractive outcomes. The multifocal IOL model with plate haptic design resulted in better optical performances than that with the modified-C haptic design.

Haptic Shape Processing in Visual Cortex

Humans typically rely upon vision to identify object shape, but we can also recognize shape via touch (haptics). Our haptic shape recognition ability raises an intriguing question: To what extent do visual cortical shape recognition mechanisms support haptic object recognition? We addressed this question using a haptic fMRI repetition design, which allowed us to identify neuronal populations sensitive to the shape of objects that were touched but not seen. In addition to the expected shape-selective fMRI responses in dorsal frontoparietal areas, we observed widespread shape-selective responses in the ventral visual cortical pathway, including primary visual cortex. Our results indicate that shape processing via touch engages many of the same neural mechanisms as visual object recognition. The shape-specific repetition effects we observed in primary visual cortex show that visual sensory areas are engaged during the haptic exploration of object shape, even in the absence of concurrent shape-related visual input. Our results complement related findings in visually deprived individuals and highlight the fundamental role of the visual system in the processing of object shape.

Designerly Ways of Not Knowing: What Designers Can Learn about Space from People Who are Blind

This paper sets out to demonstrate that architects' and other designers' visual ways of knowing may come with a considerable risk. They risk favouring visual qualities over non-visual qualities, but also cognition over embodiment in how space is understood and conceived. Their designerly ways of knowing thus may as well be viewed as designerly ways of not knowing—of disregarding the bodily experience of the built environment. This disregard becomes especially clear when considering the spatial experience of persons who are blind, as they are able to appreciate sounds, smells or haptic qualities designers may not be attuned to. Although the paper focuses on design in architecture, it points out that the underlying rationale may be relevant for other design domains as well, including urban design.

A haptic floor for interaction and diagnostics with goal based tasks during virtual reality supported balance training.

Background : Balance training of patients after stroke is one of the primary tasks of physiotherapy after the hospitalization. It is based on the intensive training, which consists of simple, repetitive, goal-based tasks. The tasks are carried out by physiotherapists, who follow predefined protocols. Introduction of a standing frame and a virtual reality decrease the physical load and number of required physiotherapists. The patients benefit in terms of safety and increased motivation. Additional feedback – haptic floor can enhance the virtual reality experience, add additional level of difficulty and could be also used for generating postural perturbations. The purpose of this article is to examine whether haptic information can be used to identify specific anomalies in dynamic posturography. Methods : The performance and stability of closed-loop system of the haptic floor were tested using frequency analysis. A postural response normative was set up from data assessed in four healthy individuals who were exposed to unexpected movements of the haptic floor in eight directions. Postural responses of a patient after stroke participating in virtual reality supported balance training, where collisions resulted in floor movements, were assessed and contrasted to the normative. Results : Haptic floor system was stable and controllable up to the frequency of 1.1 Hz, sufficient for the generation of postural perturbations. Responses obtained after perturbations in two major directions for a patient after stroke demonstrated noticeable deviations from the normative. Conclusions : Haptic floor design, together with a standing frame and a virtual reality used for balance training, enables an assessment of directionally specific postural responses. The system was designed to identify postural disorders during balance training and rehabilitation progress outside specialized clinics, e.g. at patient’s home.

Haptic interaction design using Synth-A-Modeler

Synth-A-Modeler is an open-source and modular software environment for designing physical models using a mechanical analog approach. Notably, physical models provide the most reliable method for programming haptic force-feedback interactions that can be ported across a wide array of haptic devices and usage scenarios. In this presentation, we explain how Synth-A-Modeler facilitates teaching haptic interaction design, with an emphasis on audio-haptic interaction. A series of example models demonstrates how mass-interaction, modal synthesis, and digital waveguide elements, as well as combinations thereof, can be employed in Synth-A-Modeler to simulate virtual audio-haptic environments. Although Synth-A-Modeler can hide the details of the model implementations, some equations are employed to calibrate the models. The models are tested with the FireFader open-source haptic device; however, the models should be compatible with a wide array of other haptic devices and DSP targets as well.

Accessible haptic user interface design approach for users with visual impairments

With the number of people with visual impairments (e.g., low vision and blind) continuing to increase, vision loss has become one of the most challenging disabilities. Today, haptic technology, usi...

Biomechanical and optical properties of 2 new hydrophobic platforms for intraocular lenses

To compare the biomechanical and optical properties of 2 new hydrophobic platforms and a series of commercially available foldable intraocular lenses (IOLs). Center for Education and Research on Macromolecules, University of Liège, Liège, Belgium. Experimental study. Eleven benchmark foldable IOLs (iPure, Podeye, Acrysof SN60WF, Envista MX60, Sensar AR40e, Tecnis ZCB00, Isert 251, AF-1 YA-60BB, Finevision, Acri.Tec 366D, and Ioflex) were tested by standard analytical methods for biomechanical, rheological, and optical investigations under identical conditions. With 1 exception, IOLs equilibrated in aqueous medium had a lower glass-transition temperature, higher deformability, lower injection forces, and complete recovery of their initial optical properties after injection. Typical hydrophobic acrylic dry-packaged IOLs required higher injection forces with high residual deformation and lost part of their initial optical quality after injection. Hydrophobic acrylic C-loop, double C-loop, and closed quadripod haptics applied optimum compression forces to the capsular bag with negligible optic axial displacement and tilt compared with plate haptics and poly(methyl methacrylate) haptics. The combination of the C-loop haptic and the bioadhesive glistening-free material, which absorbs a predetermined amount of water, allowed for a biomechanically stable IOL. The same material used in association with a double C-loop haptic design facilitated the perioperative manipulation and placement of the IOL in a smaller capsular bag without impairing the other biomechanical properties of a single C-loop design.

Clinical and Optical Intraocular Performance of Rotationally Asymmetric Multifocal IOL Plate-Haptic Design Versus C-Loop Haptic Design

To compare the visual and intraocular optical quality outcomes with different designs of the refractive rotationally asymmetric multifocal intraocular lens (MFIOL) (Lentis Mplus; Oculentis GmbH, Berlin, Germany) with or without capsular tension ring (CTR) implantation. One hundred thirty-five consecutive eyes of 78 patients with cataract (ages 36 to 82 years) were divided into three groups: 43 eyes implanted with the C-Loop haptic design without CTR (C-Loop haptic only group); 47 eyes implanted with the C-Loop haptic design with CTR (C-Loop haptic with CTR group); and 45 eyes implanted with the plate-haptic design (plate-haptic group). Visual acuity, contrast sensitivity, defocus curve, and ocular and intraocular optical quality were evaluated at 3 months postoperatively. Significant differences in the postoperative sphere were found (P = .01), with a more myopic postoperative refraction for the C-Loop haptic only group. No significant differences were detected in photopic and scotopic contrast sensitivity among groups (P ⩾ .05). Significantly better visual acuities were present in the C-Loop haptic with CTR group for the defocus levels of -2.0, -1.5, -1.0, and -0.50 D (P ⩽.03). Statistically significant differences among groups were found in total intraocular root mean square (RMS), high-order intraocular RMS, and intraocular coma-like RMS aberrations (P ⩽.04), with lower values from the plate-haptic group. The plate-haptic design and the C-Loop haptic design with CTR implantation both allow good visual rehabilitation. However, better refractive predictability and intraocular optical quality was obtained with the plate-haptic design without CTR implantation. The plate-haptic design seems to be a better design to support rotational asymmetric MFIOL optics.

Effects of package visuals and haptics on brand evaluations

PurposeThis paper aims to examine how visual and haptic package design characteristics singularly and jointly affect consumers' brand impressions.Design/methodology/approachIntegrating and extending design perception with congruence and fluency theories, the paper presents three research propositions that are tested in three studies. Bottled water serves as an example category with data provided by professionals and consumers.FindingsStudy 1 identifies key types of holistic bimodal designs (Modern, Big Grip, Prototypical‐Small, Boxy Billboards, and Prototypical‐Large) based on brand visual and haptic factors. Study 2 relates these types to unique single‐modal brand impressions. Study 3 determines how consumers evaluate brands depending on the semantic congruence between haptics and visuals. Except for the excitement dimension, brand evaluations are more positive under conditions of high rather than low congruence.Research limitations/implicationsThe findings are obtained for a single category (bottled water) using experiments designed to highlight and focus consumer attention on the formation of impressions. The findings may thus not fully reflect consumer responses in actual retail purchase situations.Practical implicationsThe paper provides preliminary guidelines on how to utilize visual and haptic cues in the design of brand packages for stimulating desired consumer responses.Originality/valueThe work presented in this paper contributes to the literature on design‐based brand inferences and semantic congruence by integrating the visual with the haptic perspectives.

B-spline Surface Based Concept Design Module for Applications in Virtual Reality Environment

AbstractOver the past decade, B-spline modeling has become the standard mathematical model for representing freeform or organic objects in CAD/CAM systems. Using a B- spline surface to represent the virtual model in a haptic concept design module helps to streamline the exchange of the information with existing CAD/CAM systems. B- spline surfaces also help increase visual realism because these represent continuous surface. At the same time, physically based virtual deformable models provide a sense of realism to the user. However, the algorithms used for interaction with the virtual model should be efficient to maintain acceptable level of virtual realism and perceive the simulation as continuous with no time lag. This paper presents a B-spline surface based concept design framework, which can be used to generate various concepts, evaluate these concepts, and provide user training. The proposed framework assumes that all deformable models are represented as B-spline surfaces. The tools used to interact wi...

7-DOF Haptic device and interface design

In this study, the developed 7-DOF haptic device (HaP-7) and its virtual reality interface are presented. The design issues, design constraints, and alternative design configurations are discussed and the potential advantages of the HaP-7 are put forward. The kinematic model of the proposed device looks like a simplified human arm kinematic model. The redundant characteristic of the device provides larger workspace and allows for appropriate posture selection for the purposes of maximization of the rigidity, transparency and stability, while minimizing the inertia and power consumption in addition to the singularity and obstacle avoidance optimization.