Image-Based Robotic System for Enhanced Minimally Invasive Intra-Articular Fracture Surgeries

Abstract: Robotic assistance can bring significant improvements to orthopedic fracture surgery: facilitate more accurate fracture fragment repositioning without open access and obviate problems related to the current minimally invasive fracture surgery techniques by providing a better clinical outcome, reduced recovery time, and health-related costs. This paper presents a new design of the robot-assisted fracture surgery (RAFS) system developed at Bristol Robotics Laboratory, featuring a new robotic architecture, and real-time 3D imaging of the fractured anatomy. The technology presented in this paper focuses on distal femur fractures, but can be adapted to the larger domain of fracture surgeries, improving the state-of-the-art in robot assistance in orthopedics. To demonstrate the enhanced performance of the RAFS system, 10 reductions of a distal femur fracture are performed using the system on a bone model. The experimental results clearly demonstrate the accuracy, effectiveness, and safety of the new RAFS system. The system allows the surgeon to precisely reduce the fractures with a reduction accuracy of 1.15 mm and 1.3°, meeting the clinical requirements for this procedure

Multi-Camera Sensor System for 3D Segmentation and Localization of Multiple Mobile Robots

This paper presents a method for obtaining the motion segmentation and 3D localization of multiple mobile robots in an intelligent space using a multi-camera sensor system. The set of calibrated and synchronized cameras are placed in fixed positions within the environment (intelligent space). The proposed algorithm for motion segmentation and 3D localization is based on the minimization of an objective function. This function includes information from all the cameras, and it does not rely on previous knowledge or invasive landmarks on board the robots. The proposed objective function depends on three groups of variables: the segmentation boundaries, the motion parameters and the depth. For the objective function minimization, we use a greedy iterative algorithm with three steps that, after initialization of segmentation boundaries and depth, are repeated until convergence

FEEDBACK LINEARIZATION FOR DECOUPLED POSITION/STIFFNESS CONTROL OF BIDIRECTIONAL ANTAGONISTIC DRIVES

To ensure safe human-robot interaction impedance robot control has arisen as one of the key challenges in robotics. This paper elaborates control of bidirectional antagonistic drives – qbmove maker pro. Due to its mechanical structure, both position and stiffness of bidirectional antagonistic drives could be controlled independently. To that end, we applied feedback linearization. Feedback linearization based approach initially decouples systems in two linear single-input-single-output subsystems: position subsystem and stiffness subsystem. The paper elaborates preconditions for feedback linearization and its implementation. The paper presents simulation results that prove the concept but points out application issues due to the complex mechanical structure of the bidirectional antagonistic drives

Passive Gravity Balancing with a Self-Regulating Mechanism for Variable Payload

Gravity balancing techniques allow for the reduction of energy consumptions in robotic systems. With the appropriate arrangements, often including springs, the overall potential energy of a manipulator can be made configuration-independent, achieving an indifferent equilibrium for any position. On the other hand, such arrangements lose their effectiveness when some of the system parameters change, including the mass. This paper proposes a method to accommodate different payloads for a mechanism with a single degree-of-freedom (DOF). By means of an auxiliary mechanism including a slider, pulleys and a counterweight, the attachment point of a spring is automatically regulated so as to maintain the system in indifferent equilibrium regardless of the position, even when the overall mass of the system varies. Practical implications for the design of the mechanism are also discussed. Simulation results confirm the effectiveness of the proposed approach

A Virtual Reality Platform for Modeling Cognitive Development

We present a virtual reality platform for developing and evaluating embodied models of cognitive development. The platform facilitates structuring of the learning agent, of its visual environment, and of other virtual characters that interact with the learning agent. It allows us to systematically study the role of the visual and social environment for the development of particular cognitive skills in a controlled fashion. We describe how it is currently being used for constructing an embodied model of the emergence of gaze following in infant-caregiver interactions and discuss the relative benefits of virtual vs. robotic modeling approaches.(1

Visual grasp point localization, classification and state recognition in robotic manipulation of cloth: an overview

© . This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/Cloth manipulation by robots is gaining popularity among researchers because of its relevance, mainly (but not only) in domestic and assistive robotics. The required science and technologies begin to be ripe for the challenges posed by the manipulation of soft materials, and many contributions have appeared in the last years. This survey provides a systematic review of existing techniques for the basic perceptual tasks of grasp point localization, state estimation and classification of cloth items, from the perspective of their manipulation by robots. This choice is grounded on the fact that any manipulative action requires to instruct the robot where to grasp, and most garment handling activities depend on the correct recognition of the type to which the particular cloth item belongs and its state. The high inter- and intraclass variability of garments, the continuous nature of the possible deformations of cloth and the evident difficulties in predicting their localization and extension on the garment piece are challenges that have encouraged the researchers to provide a plethora of methods to confront such problems, with some promising results. The present review constitutes for the first time an effort in furnishing a structured framework of these works, with the aim of helping future contributors to gain both insight and perspective on the subjectPeer ReviewedPostprint (author's final draft

Калібрування інерціально-вимірювальних модулей у польових умовах

Обсяг роботи: магістерська дисертація складає 101 сторінку, в ній міститься 34 ілюстрацій, 33 таблиці, 2 додатки та 66 використаних джерел. Калібрування інерціально-вимірювального модуля (ІВМ) є важливим етапом підготовки до роботи інерціальних навігаційних систем (ІНС), як платформних, так і безплатформних. Традиційне калібрування ІВМ з мінімум трьома гіроскопами і трьома акселерометрами проводиться в спеціалізованих лабораторіях. Однак, ІВМ з датчиками, побудованими з технологією мікроелектромеханічних систем (МЕМС), мають нестабільність параметрів, що призводить до необхідності проведення докалібрування ІВМ безпосередньо перед роботою ІНС у критичних або польових умовах. У дисертації досліджено можливість використання методу послідовних поворотів для докалібрування ІВМ в польових умовах. Для цього необхідно повернути ІВМ на незначні кути. Розрахункові співвідношення для визначення масштабних коефіцієнтів та нульових сигналів блоку акселерометрів отримано для двох положень ІВМ. Проведений експеримент підтвердив справедливість отриманих розрахункових співвідношень. Результати дослідження показують, що метод послідовних поворотів є ефективним способом докалібрування ІВМ в польових умовах. Він є більш зручним і простим у використанні, в порівнянні з традиційним калібруванням, яке вимагає спеціалізованих лабораторних умов.Calibration of the inertial measurement module (IMM) is an important stage of preparation for the operation of inertial navigation systems (INS), both platform and platformless. Traditionally, IMUs with at least three gyroscopes and three accelerometers are calibrated in specialised laboratories. However, IMUs with sensors built using microelectromechanical systems (MEMS) technology have parameter instability, which leads to the need to recalibrate the IMUs immediately before the operation of the IMS in critical or field conditions. This thesis investigates the possibility of using the method of sequential rotations for calibration of IMS in the field. To do this, it is necessary to rotate the IMS by small angles. The calculation relations for determining the scaling factors and zero signals of the accelerometer unit were obtained for two positions of the IMU. The experiment confirmed the validity of the obtained calculation relations. The results of the study show that the method of consecutive rotations is an effective way to calibrate the IMU in the field. It is more convenient and easy to use compared to traditional calibration, which requires specialised laboratory conditions