41 research outputs found

    Separating haptic guidance from task dynamics: A practical solution via cutaneous devices

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    There is much interest in using haptic feedback for training new skills or guiding human movement. However, the results of studies that have incorporated haptic guidance to train new skills are mixed, depending on task complexity and the method by which the haptic guidance is implemented. Subjects show dependency on the guidance forces and difficulty in discerning which aspects of the haptic feedback are related to the task dynamics and which are meant to convey task completion strategies. For these reasons, new methods to separate haptic cues for guidance from haptic feedback of task dynamics are needed. In this experiment, 30 subjects completed a trajectory following task using a wrist exoskeleton which also rendered task forces. To assist subjects, guidance cues were provided in one of three forms: (1) cutaneous forces from a wearable skin-stretch device on the ipsilateral forearm and (2) contralateral forearm, and (3) kinesthetic forces from a kinematically similar wrist exoskeleton operated by the contralateral arm. The efficacies of each guidance condition are compared by examining subject performance and learning rates. The results indicate that cutaneous guidance is nearly as effective as kinesthetic guidance, making it a practical and cost-effective alternative for spatially separated assistance

    RealPen: Providing Realism in Handwriting Tasks on Touch Surfaces using Auditory-Tactile Feedback

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    We present RealPen, an augmented stylus for capacitive tablet screens that recreates the physical sensation of writing on paper with a pencil, ball-point pen or marker pen. The aim is to create a more engaging experience when writing on touch surfaces, such as screens of tablet computers. This is achieved by regenerating the friction-induced oscillation and sound of a real writing tool in contact with paper. To generate realistic tactile feedback, our algorithm analyzes the frequency spectrum of the friction oscillation generated when writing with traditional tools, extracts principal frequencies, and uses the actuator's frequency response profile for an adjustment weighting function. We enhance the realism by providing the sound feedback aligned with the writing pressure and speed. Furthermore, we investigated the effects of superposition and fluctuation of several frequencies on human tactile perception, evaluated the performance of RealPen, and characterized users' perception and preference of each feedback type

    Multilayer haptic feedback for pen-based tablet interaction

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    We present a novel, multilayer interaction approach that enables state transitions between spatially above-screen and 2D on-screen feedback layers. This approach supports the exploration of haptic features that are hard to simulate using rigid 2D screens. We accomplish this by adding a haptic layer above the screen that can be actuated and interacted with (pressed on) while the user interacts with on-screen content using pen input. The haptic layer provides variable firmness and contour feedback, while its membrane functionality affords additional tactile cues like texture feedback. Through two user studies, we look at how users can use the layer in haptic exploration tasks, showing that users can discriminate well between different firmness levels, and can perceive object contour characteristics. Demonstrated also through an art application, the results show the potential of multilayer feedback to extend on-screen feedback with additional widget, tool and surface properties, and for user guidance

    A Novel Untethered Hand Wearable with Fine-Grained Cutaneous Haptic Feedback

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    During open surgery, a surgeon relies not only on the detailed view of the organ being operated upon and on being able to feel the fine details of this organ but also heavily relies on the combination of these two senses. In laparoscopic surgery, haptic feedback provides surgeons information on interaction forces between instrument and tissue. There have been many studies to mimic the haptic feedback in laparoscopic-related telerobotics studies to date. However, cutaneous feedback is mostly restricted or limited in haptic feedback-based minimally invasive studies. We argue that fine-grained information is needed in laparoscopic surgeries to study the details of the instrumentā€™s end and can convey via cutaneous feedback. We propose an exoskeleton haptic hand wearable which consists of five 4 ā‡„ 4 miniaturized fingertip actuators, 80 in total, to convey cutaneous feedback. The wearable is described as modular, lightweight, Bluetooth, and WiFi-enabled, and has a maximum power consumption of 830 mW. Software is developed to demonstrate rapid tactile actuation of edges; this allows the user to feel the contours in cutaneous feedback. Moreover, to demonstrate the idea as an object displayed on a flat monitor, initial tests were carried out in 2D. In the second phase, the wearable exoskeleton glove is then further developed to feel 3D virtual objects by using a virtual reality (VR) headset demonstrated by a VR environment. Two-dimensional and 3D objects were tested by our novel untethered haptic hand wearable. Our results show that untethered humans understand actuation in cutaneous feedback just in a single tapping with 92.22% accuracy. Our wearable has an average latency of 46.5 ms, which is much less than the 600 ms tolerable delay acceptable by a surgeon in teleoperation. Therefore, we suggest our untethered hand wearable to enhance multimodal perception in minimally invasive surgeries to naturally feel the immediate environments of the instruments

    Haptics: Science, Technology, Applications

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    This open access book constitutes the proceedings of the 13th International Conference on Human Haptic Sensing and Touch Enabled Computer Applications, EuroHaptics 2022, held in Hamburg, Germany, in May 2022. The 36 regular papers included in this book were carefully reviewed and selected from 129 submissions. They were organized in topical sections as follows: haptic science; haptic technology; and haptic applications

    Ilaptic Feedback Device for Needle Insertion

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    Tele-surgery is one of the emerging fields which combine engineering and medical sciences. Application of tole-surgery can be found in remote communities, war-zones and disasterstricken areas. One of the most complex and tedious issue in tele-surgery is needle insertion. The surgeon relies on haptic feedback during needle insertion. The force exerted on needle during insertion is measured and reproduced at surgeon's end is known as haptic feedback. The realistic force reproduction requires haptic feedback device which should be dynamically identical to needle. The haptic feedback device enables the surgeon to sense the needle insertion remotely. The basic objective of this thesis is to design a device used for needle insertions in soft tissue. The force information from needle insertions is measured by a sensor. The force feedback produced by the device can be used in robot-assisted needle insertion. A device is designed for reality-based data that results in more accurate representation of a needle insertion haptic feedback scenario. The device is modeled dynamically and it is clear from the model that the reactive force is reproduced by the friction forces which is controlled by the motors. The system is sensitive to mass of rollers, mass of the stick and friction between the stick and rollers. The needle insertion force is modeled in three parts; force due to capsule stiffness, friction, and cutting. The force due to capsule stiffness is modeled terms of three components namely diameter of needle, elasticity of tissue and deformation of tissue. The data from model is compared with real time force data. The haptic feedback device input and output forces are compared and the highest correlation factor is 82%. The sensitivity analysis of the device is performed. The capsule stiffness force for 0.9 millimeter diameter needle is 0.98 Newton, the stiffness force for 0.8 millimeter is 0.91 Newton and stiffness force for 0.6 millimeter diameter is 0.41 Newton. The capsule stiffness force for 0.6 millimeter needle is not following the capsule stiffness model. The insertion force data was collected on chicken skin and meat. The device designed in this work is having one degree of freedom; it only produces force feedback for vertical needle insertion. This design is not able to produce the force feedback for angular needle insertion. Graphical User Interface is designed for the visual haptic feedback. The data acquisition is done with the help of a PC sound card. Future work should include the design of a multidegree of freedom haptic feedback device and to advance the GUI for audio feedback that may be extended to accommodate the design of a simulator

    Design of a stylus with variable tip compliance

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    Humans are known to modulate the impedance properties of their ļ¬ngers in order to physically interact with the environment. For instance, painting or palpating fragile objects require high compliance of the ļ¬ngers, while writing and measuring entails high precision position control, for which the stiļ¬€ness of the ļ¬ngers is increased considerably. In this thesis, we present the design, modeling, implementation, characterization and user veriļ¬cation of a stylus with variable tip compliance. In particular, we propose a variable stiļ¬€ness mechanism as a compliant stylus that features an adjustable tip stiļ¬€ness such that users can modulate compliance as needed to match the requirements of the task they perform. The variable stiļ¬€ness of the stylus tip is achieved through transverse stiļ¬€ness variations of axially loaded beams around their critical buckling load. Integrating an axially loaded beam with a compliant transmission mechanism, the stylus tip stiļ¬€ness can be modulated over a large range. In particular, very low stiļ¬€ness levels can be rendered with high ļ¬delity, without sacriļ¬cing the mechanical integrity and load bearing capacity of the stylus. Compliant transmission mechanism of the stylus is analyzed through pseudo rigid body modeling which is a convenient and eļ¬ƒcient way of modeling ļ¬‚exible elements exhibiting non-linear characteristics under large deļ¬‚ections. Furthermore, a novel pseudo rigid body model for a ļ¬xed-guided buckling beam that captures the iii transverse stiļ¬€ness variations around the ļ¬rst critical buckling load is proposed and veriļ¬ed. These models are integrated to derive a lumped parameter model of the compliant stylus with adjustable tip stiļ¬€ness. The lumped parameter model due to pseudo rigid body modeling promotes ease of analysis for design, by hiding the underlying modeling complexities of continuum mechanics from the designer. We provide experimental characterization results detailing the range of stiļ¬€ness modulation achieved with several prototypes and verifying the accuracy of the equivalent pseudo rigid body model. We also present a set of human subject experiments that provide evidence in establishing the eļ¬ƒcacy of the modulated stylus stiļ¬€ness on the human performance
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