关键词： Adaptive control   Underactuated robots   Unmodeled dynamics   Moving platforms  

摘要： This paper develops an adaptive controller for underactuated robotic systems with unmodeled dynamics. The control scheme is motivated by the applications of manipulators operating on dynamic platforms. The design decouples the system's adaptation and control loops to allow for fast estimation rates, while guaranteeing bounded deviation from a nonadaptive reference system. The proposed formulation is independent of detailed information about the system model. The control scheme is tested in different trajectory-tracking scenarios: (i) a manipulator installed on a ship operating in a high-sea state with uncertain environmental disturbances and (ii) a mobile manipulator moving across a rough terrain of unknown geometry. The simulation results illustrate the tracking performance of the proposed control algorithm, its ability to deal with unmodeled dynamics, and its robustness to measurement noise and time delay, while maintaining smooth control signals. (C) 2014 Elsevier B.V. All rights reserved.

关键词： Tethered space robot   Dynamics modelling   Coordinated control   Optimal control  

摘要： Tethered space robots use tethers to replace rigid arms and have more flexibility than a traditional space robot, which gives it wide application prospect in future on-orbit servicing missions. Before carrying out elaborate manipulations, tethered operation robots need to approach the target. In order to save fuel in the approaching phase, various coordinated control methods that employ tethers and thrusters together are investigated in the literature. However, the increasing mass of the tether and the distributed force acting on the tether will affect the position and attitude of the robot, which is neglected in previous studies and can degrade the performance of the control system. Here, in order to involve these factors, coupled dynamics and coordinated control theories are combined and applied. Firstly, a coupling dynamics model for the tethered space robot system is built based on the Hamilton principle and the linear assumption. Then, based on the dynamics model, we design an optimal coordinated controller which can minimize the fuel consumption by using the hp-adaptive pseudospectral method and the classical PD controller. Finally, the advantages of the proposed method and the performance of the designed controller are validated by the numerical simulation. (C) 2014 Elsevier Masson SAS. All rights reserved.

关键词： Vesicoscopic reimplant   Vesicoureteral reflux   Ureteral reimpantation  

摘要： Vesicoscopic ureteral reimplantation is a challenging procedure to learn but does have outcomes equivalent to standard open repair. Children objectively have less pain than after an open cross-trigonal repair. Operative times compare favorably to other forms of minimally invasive surgery.

关键词： Minimally invasive surgery   Laparoscopy   Pediatrics   Robotic surgery   Da Vinci surgery   Ureteropelvic junction obstruction  

摘要： Ureteropelvic junction (UPJ) obstruction is a common anomaly, and presents clinically in all pediatric age groups. The past 3 decades have witnessed an evolution in the surgical correction of UPJ obstruction on several fronts, with open surgical techniques yielding way to endoscopic, laparoscopic, and robotic-assisted approaches. Robotic-assisted surgery has several advantages in complex laparoscopic reconstructive procedures such as pyeloplasty. Comparative studies of laparoscopic and robot-assisted repairs have demonstrated similar success rates. Laparoscopic pyeloplasty is here to stay because of its advantages of safety, efficacy, decreased morbidity, reduced hospital stay, and, perhaps most importantly, cost-effectiveness.

关键词： Mobile robots   dynamics   adaptive control   nonholonomic   visual servoing  

摘要： The visual servoing feedback torque stabilization controller of a nonholonomic mobile robot is developed in this paper. Firstly, a camera-object visual servoing kinematic model is introduced and a kinematic stabilizing controller is designed for the kinematic model. Then, an adaptive torque stabilizing controller is proposed in the presence of parametric uncertainties associated with the mechanical dynamics and the camera system. The stability of the proposed control system is rigorously proved through the Lyapunov method. Simulation results are provided to illustrate the performance of the control law.

关键词： kinematics   Medical   robotics   Physical Education   Safes   United States  

摘要： Objective: Endovascular robotics systems, now approved for clinical use in the United States and Europe, are seeing rapid growth in interest. Determining who has sufficient expertise for safe and effective clinical use remains elusive. Our aim was to analyze performance on a robotic platform to determine what defines an expert user. Methods: During three sessions, 21 subjects with a range of endovascular expertise and endovascular robotic experience (novices < 2 hours to moderate-extensive experience with > 20 hours) performed four tasks on a training model. All participants completed a 2-hour training session on the robot by a certified instructor. Completion times, global rating scores, and motion metrics were collected to assess performance. Electromagnetic tracking was used to capture and to analyze catheter tip motion. Motion analysis was based on derivations of speed and position including spectral arc length and total number of submovements (inversely proportional to proficiency of motion) and duration of submovements (directly proportional to proficiency). Results: Ninety-eight percent of competent subjects successfully completed the tasks within the given time, whereas 91% of noncompetent subjects were successful. There was no significant difference in completion times between competent and noncompetent users except for the posterior branch (151 s: 105 s;P = .01). The competent users had more efficient motion as evidenced by statistically significant differences in the metrics of motion analysis. Users with > 20 hours of experience performed significantly better than those newer to the system, independent of prior endovascular experience. Conclusions: This study demonstrates that motion-based metrics can differentiate novice from trained users of flexible robotics systems for basic endovascular tasks. Efficiency of catheter movement, consistency of performance, and learning curves may help identify users who are sufficiently trained for safe clinical use of

关键词： Artificial intelligence   Robotics   Philosophy   Ethics   Humanitarian   Human rights  

摘要： The enduring progression of artificial intelligence and cybernetics offers an ever-closer possibility of rational and sentient robots. The ethics and morals deriving from this technological prospect have been considered in the philosophy of artificial intelligence, the design of automatons with roboethics and the contemplation of machine ethics through the concept of artificial moral agents. Across these categories, the robotics laws first proposed by Isaac Asimov in the twentieth century remain well-recognised and esteemed due to their specification of preventing human harm, stipulating obedience to humans and incorporating robotic self-protection. However the overwhelming predominance in the study of this field has focussed on human-robot interactions without fully considering the ethical inevitability of future artificial intelligences communicating together and has not addressed the moral nature of robot-robot interactions. A new robotic law is proposed and termed AIonAI or artificial intelligence-on-artificial intelligence. This law tackles the overlooked area where future artificial intelligences will likely interact amongst themselves, potentially leading to exploitation. As such, they would benefit from adopting a universal law of rights to recognise inherent dignity and the inalienable rights of artificial intelligences. Such a consideration can help prevent exploitation and abuse of rational and sentient beings, but would also importantly reflect on our moral code of ethics and the humanity of our civilisation.

关键词： Robotics   Bladder augmentation   Neurogenic bladder   Continent   Mitrofanoff   Minimally-invasive  

摘要： There is growing interest in applying robotic-assisted laparoscopic techniques to complex reconstructive pelvic surgery owing to inherent benefits of precision, tissue handling, and articulating instruments for suturing. This review examines preliminary experiences with robotic-assisted laparoscopic augmentation ileocystoplasty and Mitrofanoff appendicovesicostomy (RALIMA) as either an isolated or combined procedure. These series suggest RALIMA is feasible, with the benefit of early recovery and improved cosmetic results in selected patients. The robotic approach incurs functional outcomes and complication rates similar to those of open techniques. Given the steep learning curve, only surgeons with extensive robotic experience are currently adopting this technique.

关键词： hydrogels   tough   LCST   actuator   robotics  

摘要： Tough Al-alginate/poly(N-isopropylacrylamide) (PNIPAM) hydrogel has been synthesized by introducing an interpenetrating network with hybrid physically cross-linked alginate and chemically cross-linked PNIPAM. Varying the concentration of AlCl3 regulates the mechanical properties of the tough hydrogel and tunes its lower critical solution temperature (LCST) as well. The tough Al-alginate/PNIPAM exhibits 6.3 +/- 0.3 MPa of compressive stress and 9.95 of uniaxial stretch. Tunability of LCST is also achieved in a wide range within 22.5-32 degrees C. A bending beam actuator and a four-arm gripper made of bilayer (Na-alginate/PNIPAM)/(Al-alginate/PNIPAM) hydrogel as prototype of all-hydrogel soft robotics are demonstrated. A finite element (FE) simulation model is developed to simulate the deformation of the soft robotics. The FE simulation not only reproduces the deformation process of performed experiments but also predicts more complicated devices that can be explored in the future. This work broadens the application of temperature-responsive PNIPAM-based hydrogels.

关键词： 青蛙   机器人   动力学分析   MATLAB   ADAMS  

摘要： 仿青蛙游动机器人的动力学分析,是研制仿青蛙水下机器人的基础。通过对所研制的仿青蛙游动机器人机构进行简化,建立机器人系统运动学模型。在此基础上,利用拉格朗日法建立机器人系统的动力学方程,通过逆动力学分析将前期生物青蛙观测实验获取的各关节运动轨迹转化为各关节驱动力矩,最后通过对比分析分别利用MATLAB和ADAMS得到的各关节驱动力矩在一个运动周期内的变化曲线,不仅验证了动力学方程的正确性,也为后期机器人控制系统的设计提供了理论依据。