6,223 research outputs found
Towards Robotic Transseptal Puncture: A Preliminary Study Investigating the Influence of Puncture Velocity in Minimally Invasive Cardiovascular Surgery
No full textMinimally invasive cardiac surgery (MI CS) has revolutionized cardiovascular interventions. A crucial step during many MI CS targeting the left side of the heart is the transeptal puncture (TP) performed in the fossa ovalis (FO). Performing a manual TP poses challenges, requiring a high level of expertise and a steep learning curve. This has motivated interest in the exploration of robotic transseptal puncture, aiming to improve the accuracy of execution. This study conducts a comprehensive analysis of the impact of puncture speed on TP safety using a robotic implementation system and a specially designed FO simulator. Specifically, a 7 Degree of Freedoms (DoFs). manipulator was used to perform the puncture using the standard transseptal kit commonly used in manual TP. Moreovere, to measure the interaction forces between the needle and the tissue, a load cell was attached to the base of the end effector of the manipulator. The simulator was built and validated against existing models proposed in the literature, successfully replicating the anatomical features and mechanical properties of the fossa ovalis tissue. Experimental results demonstrate that higher puncture velocities are associ-ated with reduced needle shear forces, improving the overall safety of the procedure
Teleoperation Control of an Underactuated Bionic Hand: Comparison between Wearable and Vision-Tracking-Based Methods
No full textBionic hands have been employed in a wide range of applications, including prosthetics, robotic grasping, and human–robot interaction. However, considering the underactuated and nonlin-ear characteristics, as well as the mechanical structure’s backlash, achieving natural and intuitive teleoperation control of an underactuated bionic hand remains a critical issue. In this paper, the teleoperation control of an underactuated bionic hand using wearable and vision-tracking system-based methods is investigated. Firstly, the nonlinear behaviour of the bionic hand is observed and the kinematics model is formulated. Then, the wearable-glove-based and the vision-tracking-based teleoperation control frameworks are implemented, respectively. Furthermore, experiments are conducted to demonstrate the feasibility and performance of these two methods in terms of accuracy in both static and dynamic scenarios. Finally, a user study and demonstration experiments are conducted to verify the performance of these two approaches in grasp tasks. Both developed systems proved to be exploitable in both powered and precise grasp tasks using the underactuated bionic hand, with a success rate of 98.6% and 96.5%, respectively. The glove-based method turned out to be more accurate and better performing than the vision-based one, but also less comfortable, requiring greater effort by the user. By further incorporating a robot manipulator, the system can be utilised to perform grasp, delivery, or handover tasks in daily, risky, and infectious scenarios
Human-Inspired Active Compliant and Passive Shared Control Framework for Robotic Contact-Rich Tasks in Medical Applications
No full textThis work presents a compliant and passive shared control framework for teleoperated robot-assisted tasks. Inspired by the human operator's capability of continuously regulating the arm impedance to perform contact-rich tasks, a novel control schema, exploiting the variable impedance control framework for force tracking is proposed. Moreover, bilateral teleoperation and shared control strategies are implemented to alleviate the human operator's workload. Furthermore, a global energy tank-based approach is integrated to enforce the system's passivity. The proposed framework is first evaluated to assess the force-tracking capability when the robot autonomously performs contact-rich tasks, e.g., in an ultrasound scanning scenario. Then, a validation experiment is conducted utilizing the proposed shared control framework. Finally, the system's usability is investigated with 12 users. The experiment results in system assessment revealed a maximum median error of 0.25 N across all the force-tracking experiment setups, i.e., constant and time-varying ones. Then, the validation experiment demonstrated significant improvements regarding the force tracking tasks compared to conventional control methods, and the system passivity was preserved during the task execution. Finally, the usability experiment shows that the human operator workload is significantly reduced by 54.6% compared to the other two control modalities. The proposed framework holds significant potential for the execution of remote robot-assisted medical procedures, such as palpation and ultrasound scanning, particularly in addressing deformation challenges while ensuring safety, compliance, and system passivity
Optimization-Based Variable Impedance Control of Robotic Manipulator for Medical Contact Tasks
No full textThis work presents an optimization-based variable impedance control strategy for controlling a robotic manipulator in medical contact tasks. Specifically, the optimal robot stiffness for performing the medical contact task is obtained using online Quadratic programming (QP). In the meantime, an energy tank approach is incorporated into the control loop to regulate the system's passivity. To verify the performance of the proposed strategy, experiments are conducted on both 'static' and 'scanning' medical contact tasks, utilizing materials with different properties, different magnitudes of contact forces, as well as uneven conditions with a human torso phantom model and slope surface. The maximum Root Mean Square Error (RMSE) of force tracking with the proposed method in the 'static' and 'scanning' tasks, across all setups, is 0.88 and 0.5 N, respectively. The experiment results demonstrate the superiority of the proposed control strategy compared with traditional manual contact and constant stiffness (CS) impedance control-based ones. The proposed control framework is promising to be integrated into robot-assisted medical contact tasks, for example, the palpation and Ultrasound (US) imaging scenarios
Optimization-Based Variable Impedance Control of Robotic Manipulator for Medical Scanning Task
No full textFu Describing About the Author Himself: A Focus on Ban Gu "You tong fu"
No full textFrom Later Han dynasty onwards, the number of fu describing about the author himself has increased. There are several possible reasons for this, but the most important reason is probably that there was no other genre through which one could express oneself except for fu in this period. For instance, the fiveword poetry was still in the middle way of establishing its own style at that moment. Moreover, in Former Han, there were few opportunities for authors to talk about themselves in detail in fu, because the main readers were emperors and kings of countries. In Later Han, the readers had become more diverse. That is probably the reason why more fu began to mention about the authors themselves in this period. Ban Gu (32-92), who is a representative scholar of Later Han and also a man of letters, expressed his aim by writing "You tong fu". Its main content is that though one's encounter with a disaster or felicity is not always derived from our behavior, we have to have a strong will and take action to overcome disasters. This idea is supported by Ban Gu's experiences of not attaining his aim. Such experiences are common in Chinese authors. One of the earliest examples is Chu Ci. Also, Chu Ci is the one of the origins of fu. It is surprising that authors expressed things about themselves mostly in fu describing journeys. It may be easier to understand this tendency if we think they substituted the heaven wander in Chu Ci with a ground journey. Chu Ci was a model for authors to express their aim which could not come true, even if the journey on the ground and the wander in heaven are different
Online Iterative Adaptive Dynamic Programming Approach for Solving the Zero-Sum Game for Nonlinear Continuous-Time Systems with Partially Unknown Dynamics
No full textThe current study presents an online iterative adaptive dynamic programming approach to resolve the zero-sum game (ZSG) for nonlinear continuous-time (CT) systems containing a partially unknown dynamic. The Hamilton-Jacobian-Issacs (HJI) equation is solved along the state trajectory according to the value function approximation and the policy improvement online. Relaxed dynamic programming is utilized to ensure the algorithm’s convergence. Model and costate networks were established to conduct the method. Computational simulations are performed to present the efficiency of the algorithm.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Control & Simulatio
Sensor Fusion-based Anthropomorphic Control of Under-Actuated Bionic Hand in Dynamic Environment
No full textUnder-actuated bionic hands have achieved tremendous popularity in many fields because of their advantages of lightweight, budget-friendly, satisfactory flexibility, and adaptability. Except for the bionic mechanical design, various anthropomorphic control strategies have been proposed and investigated in the last decades. However, due to its under-actuated characteristic, there are still many challenges for anthropomorphic control of all the degrees of freedom (DOFs) using less input. It is challenging to map the human hand kinematic synergies on robotic hands, particularly for a dynamic environment. Therefore, it is worth studying how to control the under-actuated bionic hand effectively in a dynamic environment. In this paper, an anthropomorphic control method is proposed using sensor fusion of hand kinematic inputs to control the under-actuated bionic hand. In order to map the kinematics of human fingers to the bionic hand, a novel finger bending angle is defined to represent the posture of human fingers. Multiple Leap Motion Controllers (LMC) are fused to estimate the stable and accurate finger bending angles to avoid the occlusion problem. Finally, experiments with real-time control of the under-actuated bionic hand are implemented to demonstrate the proposed approach's effectiveness
Note of congratulations from Jack Huang to Dr. Frank Fu, January 1, 1983
No full textA note of congratulations to Dr. Frank H. Fu (Fu Haojian) from Springfield College Alum, Jack Huang, Class of 1936, dated January 1, 1983. The card has country lane scene on the front, with a tree with pink leaves, a buttfly, and a tree with its leaves still green. There is the roof of a house just visible over the hill. It also says Congratulations. Inside is short message.Mr. Huang wrote a short personal note congratulating him for his efforts and the recent recognition by then President Ronald Reagan, or the actor as he refers to him, and saying how proud the Chinese are of him. An author of 17 textbooks and more than 100 journal articles, Frank H. Fu, G’73, DPE’75, has worked across the world in China, Canada, and the United States. Throughout his career, he has received many distinguished honors, including the Medal of Honor in 2009 by the SAR Government of Hong Kong.
Fu has held positions at institutions such as the Chinese University of Hong Kong and Springfield College, where he served as director of the International Center starting in 1978. Five years later, Fu returned to Hong Kong, but has since remained actively involved with Springfield College, participating in talks on the campus and even hosting a gathering of nearly 60 alumni in Hong Kong.
Currently, Fu is the associate vice president of Hong Kong Baptist University, where he also works as the director of the Dr. Stephen Hui Research Centre of Physical Recreation and Wellness. In addition, Fu is president of the Society of Chinese Scholars on Exercise Physiology and Fitness, chairperson of Hong Kong Coach Education Committee, a research fellow of the Research Consortium of SHAPE America, and an international fellow of the National Academy of Kinesiology
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