Modeling and Simulation of Acoustic Pressure Field for Ultrasonic Tactile Displays

As the virtual and augmented reality industry continues to grow, it is important to develop a tactile display technology that can seamlessly integrate into a multimodal VR experience. Ultrasonic haptic display technology uses a phased array of ultrasound transducers to create a mid-air pressure focal point, and a modulation of this radiation field at a frequency around 100-300 Hz can stimulate the mechanoreceptors in the skin to produce a tactile sensation. Optimizing this technology to create a strong pressure intensity and focality at low cost and in small space can help open up a new commercial market for tactile displays.This study explores the creation of a simple and modularized pressure field simulator for ultrasonic haptic displays using a simplified model of transducer radiation pattern. The radiation behavior is broken down to a combination of an on-axis radiation behavior and a directivity behavior, each modeled by an exponential and a Gaussian function, respectively. Then, some physical characteristics of phased array are examined to evaluate their influence on peak intensity of focal peak, focal radius, and number of significant secondary focal peaks. The results of the simulator are then compared against the real pressure field of a haptic display prototype

Prevalence of haptic feedback in robot-mediated surgery : a systematic review of literature

© 2017 Springer-Verlag. This is a post-peer-review, pre-copyedit version of an article published in Journal of Robotic Surgery. The final authenticated version is available online at: https://doi.org/10.1007/s11701-017-0763-4With the successful uptake and inclusion of robotic systems in minimally invasive surgery and with the increasing application of robotic surgery (RS) in numerous surgical specialities worldwide, there is now a need to develop and enhance the technology further. One such improvement is the implementation and amalgamation of haptic feedback technology into RS which will permit the operating surgeon on the console to receive haptic information on the type of tissue being operated on. The main advantage of using this is to allow the operating surgeon to feel and control the amount of force applied to different tissues during surgery thus minimising the risk of tissue damage due to both the direct and indirect effects of excessive tissue force or tension being applied during RS. We performed a two-rater systematic review to identify the latest developments and potential avenues of improving technology in the application and implementation of haptic feedback technology to the operating surgeon on the console during RS. This review provides a summary of technological enhancements in RS, considering different stages of work, from proof of concept to cadaver tissue testing, surgery in animals, and finally real implementation in surgical practice. We identify that at the time of this review, while there is a unanimous agreement regarding need for haptic and tactile feedback, there are no solutions or products available that address this need. There is a scope and need for new developments in haptic augmentation for robot-mediated surgery with the aim of improving patient care and robotic surgical technology further.Peer reviewe

OpenMPD: A Low-Level Presentation Engine for Multimodal Particle-Based Displays

Phased arrays of transducers have been quickly evolving in terms of software and hardware with applications in haptics (acoustic vibrations), display (levitation), and audio. Most recently, Multimodal Particle-based Displays (MPDs) have even demonstrated volumetric content that can be seen, heard, and felt simultaneously, without additional instrumentation. However, current software tools only support individual modalities and they do not address the integration and exploitation of the multi-modal potential of MPDs. This is because there is no standardized presentation pipeline tackling the challenges related to presenting such kind of multi-modal content (e.g., multi-modal support, multi-rate synchronization at 10 KHz, visual rendering or synchronization and continuity). This article presents OpenMPD, a low-level presentation engine that deals with these challenges and allows structured exploitation of any type of MPD content (i.e., visual, tactile, audio). We characterize OpenMPD’s performance and illustrate how it can be integrated into higher-level development tools (i.e., Unity game engine). We then illustrate its ability to enable novel presentation capabilities, such as support of multiple MPD contents, dexterous manipulations of fast-moving particles, or novel swept-volume MPD content

Design of Novel Sensors and Instruments for Minimally Invasive Lung Tumour Localization via Palpation

Minimally Invasive Thoracoscopic Surgery (MITS) has become the treatment of choice for lung cancer. However, MITS prevents the surgeons from using manual palpation, thereby often making it challenging to reliably locate the tumours for resection. This thesis presents the design, analysis and validation of novel tactile sensors, a novel miniature force sensor, a robotic instrument, and a wireless hand-held instrument to address this limitation. The low-cost, disposable tactile sensors have been shown to easily detect a 5 mm tumour located 10 mm deep in soft tissue. The force sensor can measure six degrees of freedom forces and torques with temperature compensation using a single optical fiber. The robotic instrument is compatible with the da Vinci surgical robot and allows the use of tactile sensing, force sensing and ultrasound to localize the tumours. The wireless hand-held instrument allows the use of tactile sensing in procedures where a robot is not available

Sensory augmentation with distal touch: The tactile helmet project

The Tactile Helmet is designed to augment a wearer's senses with a long range sense of touch. Tactile specialist animals such as rats and mice are capable of rapidly acquiring detailed information about their environment from their whiskers by using task-sensitive strategies. Providing similar information about the nearby environment, in tactile form, to a human operator could prove invaluable for search and rescue operations, or for partially-sighted people. Two key aspects of the Tactile Helmet are sensory augmentation, and active sensing. A haptic display is used to provide the user with ultrasonic range information. This can be interpreted in addition to, rather than instead of, visual or auditory information. Active sensing systems "are purposive and information-seeking sensory systems, involving task specific control of the sensory apparatus" [1]. The integration of an accelerometer allows the device to actively gate the delivery of sensory information to the user, depending on their movement. Here we describe the hardware, sensory transduction and characterisation of the Tactile Helmet device, before outlining potential use cases and benefits of the system. © 2013 Springer-Verlag Berlin Heidelberg

A volumetric display for visual, tactile and audio presentation using acoustic trapping

Science-fiction movies such as Star Wars portray volumetric systems that not only provide visual but also tactile and audible 3D content. Displays, based on swept volume surfaces, holography, optophoretics, plasmonics, or lenticular lenslets, can create 3D visual content without the need for glasses or additional instrumentation. However, they are slow, have limited persistence of vision (POV) capabilities, and, most critically, rely on operating principles that cannot also produce tactile and auditive content. Here, we present for the first time a Multimodal Acoustic Trap Display (MATD): a mid-air volumetric display that can simultaneously deliver visual, auditory, and tactile content, using acoustophoresis as the single operating principle. Our system acoustically traps a particle and illuminates it with red, green, and blue light to control its colour as it quickly scans through our display volume. Using time multiplexing with a secondary trap, amplitude modulation and phase minimization, the MATD delivers simultaneous auditive and tactile content. The system demonstrates particle speeds of up to 8.75m/s and 3.75m/s in the vertical and horizontal directions respectively, offering particle manipulation capabilities superior to other optical or acoustic approaches demonstrated to date. Beyond enabling simultaneous visual, tactile and auditive content, our approach and techniques offer opportunities for non-contact, high-speed manipulation of matter, with applications in computational fabrication and biomedicine

Design of an acoustically transparent pressure sensor for breast elastography

Breast cancer is the most commonly occurring cancer in women. Only in 2018 there were over 2 million new cases all over the world. The MURAB project, pursued at the University of Twente, has the aim to improving the breast biopsy procedure by reducing costs, patient discomfort and false negative rates. A 7-DOF KUKA robot arm steers an ultrasound transducer along a precise scanning trajectory to gather 3D volume image and stiffness values of the breast. Elasticity is the property of a body to be deformed and differs between tumors tissue and soft tissue. Elastography is a non-invasive technique in which the elasticity of a tissue is determined. The aim of this study is to design an acoustically transparent pressure sensor, mounted on the tip of the ultrasound probe, that can measure pressure differences across its surface during the scan, and assess elastographic measurements. The main idea is to use a pad of a characterized material and sequentially ultrasound images able to visualize the section of the pad and evaluate its deformation during time. The transmission of ultrasound waves into a solid depends on the mechanical characteristics of the material and on its physic state. In this work the relations between the acoustic properties and the mechanical behavior of an acoustically transparent pad are studied and evaluated

The Importance of Medical Images in Medicine

The place of medical images in medicine is of great importance. The accuracy of the medical images and the high quality of the descriptions are very important for the treating physician in the thematic diagnosis of the patient. Processing, storage, reshaping, converting medical images from analog to digital form. Keywords: Medical images, analog form, digital form, pixel, matrix form, their main advantages in the transition to the system, the accuracy of images and high quality