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American control Conference

作者： Greg Mills Miroslav Krstic Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechatronical System Tianjin University of Technology Tianjin China College of Computer National University of Defense Technology Changsha China

ISBN: (纸本)9781467386838

We present a stochastic generalization to the scalar Newton-based extremum seeking algorithm which through measurements of an unknown map, maximizes the map's higher derivatives. The proposed method perturbs the estimate of the optimal parameter with the sinusoid of Brownian motion about the boundary of a circle. Then by properly demodulating the map output of the randomly perturbed estimate, the extremum seeking algorithm maximizes the nth derivative only through measurements of the map. The Newton-based extremum seeking approach removes the dependence of the convergence rate on the unknown Hessian of the higher derivative, an effort to improve performance over standard gradient-based extremum seeking. Our design stems from the existing multivariable Newton-based extremum seeking algorithm where a differential Riccati equation estimates the inverse Hessian of the function to be maximized. Algebraically computing a direct estimate of the inverse Hessian is susceptible to singularity, where-as employing the Riccati filter removes that potential. We prove local stability of the algorithm for general nonlinear static maps via stochastic averaging theory developed for extremum seeking.

关键词： Heuristic algorithms Convergence Stability analysis Optimization Demodulation Markov processes Demodulation Heuristic algorithms extremum seeking algorithm Markov chain extremum values Stability analysis Converge maps Riccati equations Hessian RATE DEPENDENCE optimal parameter

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Wire in the Cable-Driven system of Surgical Robot

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IOP Conference Series: Materials Science and Engineering 2017年第1期224卷

作者： X F Wang N Lv H Z Mu L J Xue Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechatronical System Tianjin University of Technology School of Mechanical Engineering Tianjin University of Technology School of Mechanical Engineering Zhonghuan Information College Tianjin University of Technology

During the evolution of the surgical robot, cable plays an important role. It translates motion and force precisely from surgeon's hand to the tool's tips. In the paper, the vertical wires, the composition of cable, are mathematically modeled from a geometric point of view. The cable structure and tension are analyzed according to the characteristics of wire screw twist. The structural equations of the wires in different positions are derived for both non-bent cable and bent cable, respectively. The bending moment formula of bent cable is also obtained. This will help researchers find suitable cable and design more matched pulley.

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Analysis of Dynamic Characteristics of Rugged Vessel in the Process of Hepatic Perfusion

Analysis of Dynamic Characteristics of Rugged Vessel in the ...

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IEEE International Conference on Mechatronics and Automation

作者： Songli Wang Jun Liu Yihe Liu Weimin Ge Tianjin key laboratory of the Design and Intelligent Control of the Advanced Mechanical System Tianjin University of Technology BinshuiXidao 391 Tianjin China Tianjin key Laboratory of Organ Transplantation Transplant surgery of Tianjin First Central Hospital Fukang Road 24 Tianjin China

ISBN: (纸本)9781509023974

The paper attempts to analyze the dynamic characteristics in the perfusion process of the hepatic vessel. A model of rugged vessel with a foreign matter was established based upon medical imaging data. The fluid flowing in the rugged vessel was simulated using the perfusion method of the symmetric pulsating flow (SPF) and the steady flow under the bidirectional fluid-structure interaction (FSI). The simulation results, on the one hand, demonstrate the feasibility of SPF within the perfusion process of the rugged vessel in liver. On the other hand, the results clearly show the dynamic behaviors which accorded with actual medical results. Comparing the perfusion results of the rugged vessel using SPF with the steady flow, the difference of vascular deformation is not obvious, while the peak of velocity in the rugged vessel used SPF is about 50% higher than that of the steady flow, that reveals SPF is more likely to take away the foreign matter. The study will be helpful to improve the quality of the donor liver and reduce the influence of subjective factors on the quality of cleaning, and it provides theoretical basis for the liver transplantation.

关键词： Hepatic Perfusion Rugged Vessel Symmetric Pulsating Flow Bidirectional Fluid-Structure Interaction Dynamics

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On Simulation for Fuzzy control on Oxygen Concentration of the Mixed Air Supplied by Breathing Adjuster 34

On Simulation for Fuzzy Control on Oxygen Concentration of t...

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第三十四届中国控制会议

作者： SUN Hao WANG Shou-jun SUN Qing-lin Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechatronical System The College of Mechanical Engineering Tianjin University of Technology The College of Computer and Control Engineering Nankai University Tianjin Key Laboratory of Intelligent Robotics

ISBN: (纸本)9781467374439

The breathing adjuster is the core component of life support system of an aircraft and it is very important to control the valve to make the breathing adjuster supply the pilot the mixed air with the suitable oxygen concentration. In this paper the mathematical model, which describes the relation between the opening degree of the valve of the breathing adjuster and the flight altitude of the aircraft, is set up through analyzing requirement of aviation physiology and working principles of the breathing adjuster. Then a fuzzy controller is designed to control the opening degree of the valve in order to make the breathing adjuster supply to the pilot the mixed air with suitable oxygen concentration. Finally MATLAB Simulink is employed to verify the feasibility and validity of the fuzzy controlling approach. The results of simulating experiments show that the fuzzy control approach proposed in this paper can make the breathing adjuster supply the mixed air with suitable oxygen concentration to the pilot boarded on an aircraft.

关键词： Breathing adjuster,Oxygen concentration,the opening degree of the valve,Fuzzy control,Simulation

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Modelling and analysis of planar robotic arm dynamics based on an improved transfer matrix method for multi-body systems 14

Modelling and analysis of planar robotic arm dynamics based ...

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14th International Federation for the Promotion of Mechanism and Machine Science World Congress, IFToMM 2015

作者： Chen, W. Li, H. Zhang, X.Z. Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechatronical System Tianjin China Academy of Military Medical Sciences Tianjin China

ISBN: (纸本)9789860460988

An improved transfer matrix method for multi-rigid-body systems is presented based on the structural characteristics of the manipulator and the relations between motion transfer and force transfer. Thus, a new model applicable to serial robots is obtained by using of discrete time transfer matrix method. Based on the improved method, a unified model for a manipulator with n DOF is derived. This model contains both kinematic and dynamic characteristics of the system. According to the motion transformation relation between the joint space and the operational space of the manipulator, the solution and the procedure are developed for both forward and inverse kinematics of the unified model. The simulation results of a 2DOF planar manipulator show the rightness of the modelling method and exhibit its superiority to other methods.

关键词： Inverse kinematics

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Finite Element Analysis of Absorbable Sheath to Prevent Stress Shielding of Tibial Interlocking Intramedullary Nail

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IOP Conference Series: Materials Science and Engineering 2017年第1期224卷

作者： Yansheng Dong Yongqing Wang Limin Dong Peng Jia Fengcheng Lu Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechatronical System School of Mechanical Engineering Tianjin University of Technology Tianjin 300384 China Dept of Orthopaedics the Fourth Central Hospital of Tianjin Tianjin 300140 China Tianjin University of Traditional Chinese Medicine Tianjin 300314 China Dept of Orthopaedics Tianjin Medical University Tianjin 300314 China

The nail with absorbable sheath (AS nail) is designed to reduce the stress shielding effect of internal fixation with interlocking intramedullary nail. In order to verify its feasibility, two types of the finite element models of internal fixation of tibia with the AS nail and the common metal nail (CM nail) are established using the Softwares of Mimics, Geomagic, SolidWorks and ANSYS according to the CT scanning data of tibia. The result of the finite element analysis shows that the AS nail has great advantages compared with the CM nail in reducing the stress shielding effect in different periods of fracture healing. The conclusion is that the AS nail can realize the static fixation to the dynamic fixation from the early to the later automatically to shorten the time of fracture healing, which also provides a new technique to the interlocking intramedullary nail.

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design of dual-frequency bioreactor control system

Design of dual-frequency bioreactor control system

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IEEE International Conference on Mechatronics and Automation

作者： Hongbiao Xiang Shoujun Wang Chunqiu Zhang Xingfei Li Jun Liu Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechatronical System Tianjin University of Technology Tianjin CN Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechatronical System Tianjin University Tianjin Tianjin CN

According to tissue engineering and basic principle of bionic, the low-frequency high-amplitude loading on articular cartilage is to simulate human walking or other activities, and the high-frequency low-amplitude loading is to maintain the cartilage framework structure from muscles, ligaments and other tissue. In order to build appropriate mechanical environment for cartilage tissue engineering, this paper design a dual-frequency bioreactor, and the control precision and performance is improved by a method of friction compensation. The control system is full closed loop composed of liner motor and grating scale, based on PC+PMAC opened control platform. Firstly, a dynamic equation of an open servo system is given and the friction characteristics are described based on Stribeck model. Secondly, Considering the parameters of friction model changed with the system, the controller of adaptive sliding friction compensation is designed by backstepping method, and the corresponding adaptive laws and switching functions are given. Besides, this method give analysis of its global asymptotic stability, proved by Lyapunov theorem. Finally, the adaptive sliding friction compensation control strategy is realized by Programmable Multi-Axis controller (PMAC), and the effectiveness of the method is verified by experiments. Results show that the steady state error of sinusoidal motion is decreased from the ± 22μm to ± 4μm compared with the velocity and acceleration forward feed-compensation. The dual-frequency bioreactor can simulate the mechanical environment of artificial cartilage tissue engineering on micrometer level, furthermore, it laid a foundation for the research of mechanobiology of cartilage.

关键词： Friction Mathematical model Tissue engineering Loading Adaptation models Servomotors

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Compensation of friction and elastic deformation for ball screw drive system

Compensation of friction and elastic deformation for ball sc...

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IEEE International Conference on Mechatronics and Automation

Nonlinear friction and elastic deformation seriously affect both static and dynamic performance of mechanical serve system, especially in the high-speed and high-precision systems. This paper focuses on modeling, identification, and compensation of non-linear friction and elastic deformation for ball screw drive system. Firstly, the parameters of the stribeck model are identified by the method of extended kalman filter. And then the parameters of stiffness model of the ball screw are identified by the method of the least square based on force analysis of system. Finally, the feed-forward compensation of friction and elastic deformation is performed. The experimental results show that: after the compensation, the steady state error of low-speed motion decreases from 42μm to ±3μm, and that of high-speed motion decreases from 95μm to ±5μm. Therefore, the method proposed can effectively compensate the disturbance of friction and elastic deformation, and improve the tracking accuracy of the ball screw drive system.

关键词： Friction Fasteners Mathematical model Servomotors Deformable models Tracking Force

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Study on Tool Path Optimization in Multi-axis NC Machining

Study on Tool Path Optimization in Multi-axis NC Machining

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2015年第二届机电一体化与机械工程国际学术会议

作者： Xinghua Niu Tianding Wang Bofei Shen Tiemin Zhao Qianyou Huang Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechatronical System Tianjin University of Technology

This paper presents a new generation algorithm for tool path based on the optimization of traditional ***,the tool path on an impeller is generated with UG software,and it is used to make contrasts and verifications for the effect of ***,VERICUT software with the function of the simulating on the whole manufacturing process is utilized to verify the feasibility of the optimized algorithm.

关键词： NC machining path optimization UG VERICUT

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Dynamic analysis of a 3-DOF 3-PUU parallel manipulator based on the principle of virtual work

Dynamic analysis of a 3-DOF 3-PUU parallel manipulator based...

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IEEE/ASME (AIM) International Conference on advanced intelligent Mechatronics

作者： Song Lu Yangmin Li Department of Electromechanical Engineering University of Macau Macao Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control Tianjin University of Technology Tianjin China

ISBN: (纸本)9781467391085

This paper presents a straightforward and systematical methodology for conducting the inverse dynamic analysis of a 3-prismatic-universal-universal (PUU) parallel kinematic manipulator (PKM) through employing the principle of virtual work. The proposed 3-PUU PKM possesses three translational degree-of-freedom (DOF). The position, velocity and acceleration of joints are solved via the inverse kinematic analysis, the link Jacobian matrices which map the velocity of the moving platform into the velocity and angular velocity of struts are derived in the fixed coordinate system. Based on the d'Alembert's form of the principle of virtual work, the applied generalized forces of the whole mechanical system are divided into the applied forces of moving platform, struts, sliders, and motor-coupling-leadscrew, respectively. The joint actuated torques are obtained through eliminating the virtual displacement in the dynamic equations. Furthermore, the inertial term, centrifugal and Coriolis term, and gravitational term of the total joint torque are determined. Simulation for a conical spiral trajectory demonstrates that the total torque is dominated by the inertial term.

关键词： Manipulator dynamics Joints Acceleration Dynamics Kinematics Mathematical model

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