Advanced sensors technology survey

This project assesses the state-of-the-art in advanced or 'smart' sensors technology for NASA Life Sciences research applications with an emphasis on those sensors with potential applications on the space station freedom (SSF). The objectives are: (1) to conduct literature reviews on relevant advanced sensor technology; (2) to interview various scientists and engineers in industry, academia, and government who are knowledgeable on this topic; (3) to provide viewpoints and opinions regarding the potential applications of this technology on the SSF; and (4) to provide summary charts of relevant technologies and centers where these technologies are being developed

On the Application of Mechanical Vibration in Robotics-Assisted Soft Tissue Intervention

Mechanical vibration as a way of transmitting energy has been an interesting subject to study. While cyclic oscillation is usually associated with fatigue effect, and hence a detrimental factor in failure of structures and machineries, by controlled transmission of vibration, energy can be transferred from the source to the target. In this thesis, the application of such mechanical vibration in a few surgical procedures is demonstrated. Three challenges associated with lung cancer diagnosis and treatment are chosen for this purpose, namely, Motion Compensation, tumor targeting in lung Needle Insertion and Soft Tissue Dissection: A robotic solution is proposed for compensating for the undesirable oscillatory motion of soft tissue (caused by heart beat and respiration) during needle insertion in the lung. An impedance control strategy based on a mechanical vibratory system is implemented to minimize the tissue deformation during needle insertion. A prototype was built to evaluate the proposed approach using: 1) two Mitsubishi PA10-7C robots, one for manipulating the macro part and the other for mimicking the tissue motion, 2) one motorized linear stage to handle the micro part, and 3) a Phantom Omni haptic device for remote manipulation. Experimental results are given to demonstrate the performance of the motion compensation system. A vibration-assisted needle insertion technique has been proposed in order to reduce needle–tissue friction. The LuGre friction model is employed as a basis for the study and the model is extended and analyzed to include the impact of high-frequency vibration on translational friction. Experiments are conducted to evaluate the role of insertion speed as well as vibration frequency on frictional effects. In the experiments conducted, an 18 GA brachytherapy needle was vibrated and inserted into an ex-vivo soft tissue sample using a pair of amplified piezoelectric actuators. Analysis demonstrates that the translational friction can be reduced by introducing a vibratory low-amplitude motion onto a regular insertion profile, which is usually performed at a constant rate. A robotics-assisted articulating ultrasonic surgical scalpel for minimally invasive soft tissue cutting and coagulation is designed and developed. For this purpose, the optimal design of a Langevin transducer with stepped horn profile is presented for internal-body applications. The modeling, optimization and design of the ultrasonic scalpel are performed through equivalent circuit theory and verified by finite element analysis. Moreover, a novel surgical wrist, compatible with the da Vinci® surgical system, with decoupled two degrees-of-freedom (DOFs) is developed that eliminates the strain of pulling cables and electrical wires. The developed instrument is then driven using the dVRK (da Vinci® research kit) and the Classic da Vinci® surgical system

Desktop Haptic Interface for Simulation of Hand-Tremor

This paper presents a haptic system that is conceived to support the design process of a class of products or services in order to make them more accessible to people affected by hand tremor diseases. The main aim is to foster the designer empathy allowing her/him to directly feel the effect of the impairment in first person. Specifically, a desktop haptic device is employed to induce a programmable hand-tremor, that is typically observed in people affected by some kind of neurological diseases, on healthy subjects (i.e. the designers). The developed tool is based on a wrist-attached haptic interface with a workspace that is comparable to that of the arm of the user. Such device is able to exert controlled forces on the user's wrist and induces a hand-tremor whose frequency and amplitude are correlated with those measured on impaired people. The control of the device is based on a custom trajectory-tracking algorithm that takes as input tremor signals that are acquired on patients using an optical motion tracking system. In this paper, we present the employed haptic system, the structure of the control system and the experimental validation of the controller done through the acquisition of data on six patients affected by Parkinson's disease

Shared control for natural motion and safety in hands-on robotic surgery

Hands-on robotic surgery is where the surgeon controls the tool's motion by applying forces and torques to the robot holding the tool, allowing the robot-environment interaction to be felt though the tool itself. To further improve results, shared control strategies are used to combine the strengths of the surgeon with those of the robot. One such strategy is active constraints, which prevent motion into regions deemed unsafe or unnecessary. While research in active constraints on rigid anatomy has been well-established, limited work on dynamic active constraints (DACs) for deformable soft tissue has been performed, particularly on strategies which handle multiple sensing modalities. In addition, attaching the tool to the robot imposes the end effector dynamics onto the surgeon, reducing dexterity and increasing fatigue. Current control policies on these systems only compensate for gravity, ignoring other dynamic effects. This thesis presents several research contributions to shared control in hands-on robotic surgery, which create a more natural motion for the surgeon and expand the usage of DACs to point clouds. A novel null-space based optimization technique has been developed which minimizes the end effector friction, mass, and inertia of redundant robots, creating a more natural motion, one which is closer to the feeling of the tool unattached to the robot. By operating in the null-space, the surgeon is left in full control of the procedure. A novel DACs approach has also been developed, which operates on point clouds. This allows its application to various sensing technologies, such as 3D cameras or CT scans and, therefore, various surgeries. Experimental validation in point-to-point motion trials and a virtual reality ultrasound scenario demonstrate a reduction in work when maneuvering the tool and improvements in accuracy and speed when performing virtual ultrasound scans. Overall, the results suggest that these techniques could increase the ease of use for the surgeon and improve patient safety.Open Acces

Control Architectures for Robotic Assistance in Beating Heart Surgery

Tese de doutoramento em Engenharia Electrotécnica e de Computadores, no ramo de especialização em Automação e Robótica, apresentada ao Departamento de Engenharia Electrotécnica e de Computadores da Faculdade de Ciências e Tecnologia da Universidade de CoimbraDoenças cardiovasculares são a primeira causa de morte no mundo. Todos os anos mais de 17 milhões de pessoas morrem, representando 29% do número total de mortes. As doenças coronárias são as mais críticas, atingindo mais de 7.2 milhões de mortes. Para reduzir o risco de morte, o "bypass" coronário é a intervenção cirúrgica mais comum. Atualmente este procedimento envolve uma esternotomia mediana e um "bypass" cardiopulmonar, permitindo que uma máquina externa implemente as funções de oxigenação e bombeamento de sangue. Contudo, esta máquina externa é fonte de muitas complicações pós-operatórias, incluindo a morte de pacientes. Estes problemas motivam o estudo e desenvolvimento de técnicas cirúrgicas sem parar o funcionamento do coração. Nestes casos, os batimentos cardíacos e a respiração representam as principais fontes de perturbação. Foram desenvolvidos estabilizadores mecânicos para diminuir localmente o movimento cardíaco. Colocado numa região de específica (por exemplo, na artéria coronária), estes estabilizadores limitam o movimento por pressão e sucção. Apesar dos melhoramentos feitos ao longo dos anos, ainda existe um movimento residual considerável, e o cirurgião tem que os compensar manualmente. Torna-se então natural incluir dispositivos robóticos para ajudar na prática médica, melhorando a precisão, segurançae conforto de tarefas cirúrgicas. O sistema cirúrgico da Vinci é atualmente o sistema robótico mais avançado para a prática médica, com elevado desempenho em tarefas de destreza, precisão e segurança, apesar de não fornecer soluções de realimentação táctil, nem de compensação automática de movimentos fisiológicos. O trabalho desta tese é na área da robótica para cirurgias cardíacas com o coração a bater. Baseada na realimentação da força, esta tese explora novas arquiteturas de controlo com compensação automática dos movimentos cardíacos. São feitos testes experimentais em cenários muito realistas, sem utilizar seres vivos. Um robô denominado "Heartbox" equipado com um coração real reproduz movimentos cardíacos, enquanto que outro robô manipulador aplica forças cirúrgicas nesse coração com batimento artificial. As forças de interação fornecem realimentação de contacto ao cirurgião. O principal desafio científico deste trabalho é a ligação de técnicas de compensação autónoma de movimentos fisiológicos com controlo de força e realimentação haptica.Cardiovascular diseases are the first cause of mortality in the world. More than 17 million people die every year, representing 29% of all global deaths. Among these, coronary heart diseases are the most critical ones, reaching up to 7.2 million deaths. To reduce the risk of death the coronary artery bypass grafting (CABG) is the most common surgical intervention. Currently, the procedure involves a median sternotomy, an incision in the thorax allowing a direct access to the heart, and a cardiopulmonary bypass (CPB), where heart and lung functionalities are performed by an extracorporal machine. Unfortunately the heart-lung machine is the greatest source of complications and post-operatory mortality for patients. Problems involved have motivated beating heart surgery that circumvent CPB procedure. Heartbeats and respiration represent the two main sources of disturbances during off-pump surgery. Mechanical stabilizers have been conceived for locally decreasing heart motion. Placed around a region of interest (e.g., coronary artery), these stabilizers constraint the motion by suction or pressure. Despite many improvements done over the years, considerable residual motion still remains and the surgeon have to manually compensate them. Robotic assistance has the potential to offer significant improvements to the medical practice in terms of precision, safety and comfort. Theda Vinci surgical system is the most popular and sophisticated. Although it has considerably improved dexterity, precision and safety, no solution for restoring tactile feedback to the surgeon exists and physiological motion compensation still needs to be manually canceled by the surgeon. The work presented in this thesis focus on robotic assistance for beating heart surgery. Based on force feedback, we designed new control architectures providing autonomous physiological motion compensation. Experimental assessments have been performed through a realistic scenario. A Heartbox robot equipped with an \textit{ex vivo} heart reproduces heart motion and a robot arm generates desired surgical forces on the moving heart. Interaction forces provide the haptic feedback for the surgeon. Merging autonomous motion compensation techniques with force control and haptic feedback is a major scientific challenge that we tackle in this work.FCT - SFRH/BD/74278/201

Remote Navigation and Contact-Force Control of Radiofrequency Ablation Catheters

Atrial fibrillation (AF), the most common and clinically significant heart rhythm disorder, is characterized by rapid and irregular electrical activity in the upper chambers resulting in abnormal contractions. Radiofrequency (RF) cardiac catheter ablation is a minimally invasive curative treatment that aims to electrically correct signal pathways inside the atria to restore normal sinus rhythm. Successful catheter ablation requires the complete and permanent elimination of arrhythmogenic signals by delivering transmural RF ablation lesions contiguously near and around key cardiac structures. These procedures are complex and technically challenging and, even when performed by the most skilled physician, nearly half of patients undergo repeat procedures due to incomplete elimination of the arrhythmogenic pathways. This thesis aims to incorporate innovative design to improve catheter stability and maneuverability through the development of robotic platforms that enable precise placement of reproducibly durable ablation lesions. The first part of this thesis deals with the challenges to lesion delivery imposed by cardiorespiratory motion. One of the main determinants of the delivery of durable and transmural RF lesions is the ability to define and maintain a constant contact force between the catheter tip electrode and cardiac tissue, which is hampered by the presence of cardiorespiratory motion. To address this need, I developed and evaluated a novel catheter contact-force control device. The compact electromechanical add-on tool monitors catheter-tissue contact force in real-time and simultaneously adjusts the position of a force-sensing ablation catheter within a steerable sheath to compensate for the change in contact force. In a series of in vitro and in vivo experiments, the contact-force control device demonstrated an ability to: a) maintain an average force to within 1 gram of a set level; b) reduce contact-force variation to below 5 grams (2-8-fold improvement over manual catheter intervention); c) ensure the catheter tip never lost contact with the tissue and never approached dangerous force levels; and importantly, d) deliver reproducible RF ablation lesions regardless of cardiac tissue motion, which were of the same depth and volume as lesions delivered in the absence of tissue motion. In the second part of the thesis, I describe a novel steerable sheath and catheter robotic navigation system, which incorporates the catheter contact-force controller. The robotic platform enables precise and accurate manipulation of a remote conventional steerable sheath and permits catheter-tissue contact-force control. The robotic navigation system was evaluated in vitro using a phantom that combines stationary and moving targets within an in vitro model representing a beating heart. An electrophysiologist used the robotic system to remotely navigate the sheath and catheter tip to select targets and compared the accuracy of reaching these targets performing the same tasks manually. Robotic intervention resulted in significantly higher accuracy and significantly improved the contact-force profile between the catheter tip and moving tissue-mimicking material. Our studies demonstrate that using available contact-force information within a robotic system can ensure precise and accurate placement of reliably transmural RF ablation lesions. These robotic systems can be valuable tools used to optimize RF lesion delivery techniques and ultimately improve clinical outcomes for AF ablation therapy

Feedback error learning at the muscle level: A unified model of human motor adaptation to stable and unstable dynamics

Master'sMASTER OF ENGINEERIN