The control problem of trajectory based path following for passenger vehicles is studied. Comprehensive nonlinear vehicle model is utilized for simulation vehicle response during various maneuvers in MATLAB/Simulink. ...The control problem of trajectory based path following for passenger vehicles is studied. Comprehensive nonlinear vehicle model is utilized for simulation vehicle response during various maneuvers in MATLAB/Simulink. In order to follow desired path, a driver model is developed to enhance closed loop driver/vehicle model. Then, linear quadratic regulator(LQR) controller is developed which regulates direct yaw moment and corrective steering angle on wheels. Particle swam optimization(PSO) method is utilized to optimize the LQR controller for various dynamic conditions. Simulation results indicate that, over various maneuvers, side slip angle and lateral acceleration can be reduced by 10% and 15%, respectively, which sustain the vehicle stable. Also, anti-lock brake system is designed for longitudinal dynamics of vehicle to achieve desired slip during braking and accelerating. Proposed comprehensive controller demonstrates that vehicle steerability can increase by about 15% during severe braking by preventing wheel from locking and reducing stopping distance.展开更多
A stochastic optimal control strategy for a slightly sagged cable using support motion in the cable axial direction is proposed. The nonlinear equation of cable motion in plane is derived and reduced to the equations ...A stochastic optimal control strategy for a slightly sagged cable using support motion in the cable axial direction is proposed. The nonlinear equation of cable motion in plane is derived and reduced to the equations for the first two modes of cable vibration by using the Galerkin method. The partially averaged Ito equation for controlled system energy is further derived by applying the stochastic averaging method for quasi-non-integrable Hamiltonian systems. The dynamical programming equation for the controlled system energy with a performance index is established by applying the stochastic dynamical programming principle and a stochastic optimal control law is obtained through solving the dynamical programming equation. A bilinear controller by using the direct method of Lyapunov is introduced. The comparison between the two controllers shows that the proposed stochastic optimal control strategy is superior to the bilinear control strategy in terms of higher control effectiveness and efficiency.展开更多
Subject Code:H16With the support by the National Natural Science Foundation of China,a study by the research groups led by Prof.Dong Chenfang(董辰方)from Zhejiang University School of Medicine demonstrates that AKR1B1...Subject Code:H16With the support by the National Natural Science Foundation of China,a study by the research groups led by Prof.Dong Chenfang(董辰方)from Zhejiang University School of Medicine demonstrates that AKR1B1promotes basal-like breast cancer progression by apositive feedback loop that activates the展开更多
The prevalence of frailty across the world in older adults is increasing dramatically and having frailty places a person at increased risk for many adverse health outcomes,including impaired mobility,falls,hospitaliza...The prevalence of frailty across the world in older adults is increasing dramatically and having frailty places a person at increased risk for many adverse health outcomes,including impaired mobility,falls,hospitalizations,and mortality.Globally,the concept of frailty is gaining attention and the scientific field has made great strides in identifying and conceptually defining frailty through consensus conferences,in advancing the overall science of frailty by drawing on basic science discoveries including concepts surrounding the hallmarks of aging,resilience,and intrinsic capacities,and in identifying the many challenges faced by professionals within diverse clinical settings.Currently,it is thought that frailty is preventable,thus the identification of a person's degree of frailty is vital.Identification of frailty is achievable through widely used frailty screening tools,which are valid,reliable,and easy to use.Following the identification of a person's degree of frailty,targeted intervention strategies,such as physical activity programs must be implemented.In this perspective,we provide a historical perspective of the frailty field since the last quarter of the 20th century to present.We identify the proposed underlying patho-physiology of multiple physiological systems,including compromised homeostasis and resilience.Next,we outline the available screening tools for frailty with a physical performance assessment and highlight specific benefits of physical activity.Lastly,we discuss current scientific evidence supporting the physical activity rec-ommendations for the aging population and for older adults with frailty.The goal is to emphasize early detection of frailty and stress the value of physical activity.展开更多
A novel kind of SC(superconducting) solenoid coil is designed to satisfy the homogencity requirement of the magnetic field.In this paper,we first calculate the current density distribution of the solenoid coil secti...A novel kind of SC(superconducting) solenoid coil is designed to satisfy the homogencity requirement of the magnetic field.In this paper,we first calculate the current density distribution of the solenoid coil section through the linear programming method.Then a traditional solenoid and a nonrectangular section solenoid are designed to produce a central field up to 7 T with a homogencity to the greatest extent.After comparision of the two solenoid coils designed in magnet field quality,fabrication cost and other aspects,the new design of the nonrectangular section of a solenoid coil can be realized through improving the techniques of framework fabrication and winding.Finally,the outlook and error analysis of this kind of SC magnet coil are also discussed briefly.展开更多
文摘The control problem of trajectory based path following for passenger vehicles is studied. Comprehensive nonlinear vehicle model is utilized for simulation vehicle response during various maneuvers in MATLAB/Simulink. In order to follow desired path, a driver model is developed to enhance closed loop driver/vehicle model. Then, linear quadratic regulator(LQR) controller is developed which regulates direct yaw moment and corrective steering angle on wheels. Particle swam optimization(PSO) method is utilized to optimize the LQR controller for various dynamic conditions. Simulation results indicate that, over various maneuvers, side slip angle and lateral acceleration can be reduced by 10% and 15%, respectively, which sustain the vehicle stable. Also, anti-lock brake system is designed for longitudinal dynamics of vehicle to achieve desired slip during braking and accelerating. Proposed comprehensive controller demonstrates that vehicle steerability can increase by about 15% during severe braking by preventing wheel from locking and reducing stopping distance.
基金supported by the National Natural Science Foundation of China (11072212,10932009)the Zhejiang Natural Science Foundation of China (7080070)
文摘A stochastic optimal control strategy for a slightly sagged cable using support motion in the cable axial direction is proposed. The nonlinear equation of cable motion in plane is derived and reduced to the equations for the first two modes of cable vibration by using the Galerkin method. The partially averaged Ito equation for controlled system energy is further derived by applying the stochastic averaging method for quasi-non-integrable Hamiltonian systems. The dynamical programming equation for the controlled system energy with a performance index is established by applying the stochastic dynamical programming principle and a stochastic optimal control law is obtained through solving the dynamical programming equation. A bilinear controller by using the direct method of Lyapunov is introduced. The comparison between the two controllers shows that the proposed stochastic optimal control strategy is superior to the bilinear control strategy in terms of higher control effectiveness and efficiency.
文摘Subject Code:H16With the support by the National Natural Science Foundation of China,a study by the research groups led by Prof.Dong Chenfang(董辰方)from Zhejiang University School of Medicine demonstrates that AKR1B1promotes basal-like breast cancer progression by apositive feedback loop that activates the
基金support,in part,by National Institutes of Health Grant(R56AG067724)and the Travis M.Roy Endowed Professor in Rehabilitation Sciences to LVT.
文摘The prevalence of frailty across the world in older adults is increasing dramatically and having frailty places a person at increased risk for many adverse health outcomes,including impaired mobility,falls,hospitalizations,and mortality.Globally,the concept of frailty is gaining attention and the scientific field has made great strides in identifying and conceptually defining frailty through consensus conferences,in advancing the overall science of frailty by drawing on basic science discoveries including concepts surrounding the hallmarks of aging,resilience,and intrinsic capacities,and in identifying the many challenges faced by professionals within diverse clinical settings.Currently,it is thought that frailty is preventable,thus the identification of a person's degree of frailty is vital.Identification of frailty is achievable through widely used frailty screening tools,which are valid,reliable,and easy to use.Following the identification of a person's degree of frailty,targeted intervention strategies,such as physical activity programs must be implemented.In this perspective,we provide a historical perspective of the frailty field since the last quarter of the 20th century to present.We identify the proposed underlying patho-physiology of multiple physiological systems,including compromised homeostasis and resilience.Next,we outline the available screening tools for frailty with a physical performance assessment and highlight specific benefits of physical activity.Lastly,we discuss current scientific evidence supporting the physical activity rec-ommendations for the aging population and for older adults with frailty.The goal is to emphasize early detection of frailty and stress the value of physical activity.
基金Supported hy National Natural Science Foundation of China(91026001)High-tech Projects
文摘A novel kind of SC(superconducting) solenoid coil is designed to satisfy the homogencity requirement of the magnetic field.In this paper,we first calculate the current density distribution of the solenoid coil section through the linear programming method.Then a traditional solenoid and a nonrectangular section solenoid are designed to produce a central field up to 7 T with a homogencity to the greatest extent.After comparision of the two solenoid coils designed in magnet field quality,fabrication cost and other aspects,the new design of the nonrectangular section of a solenoid coil can be realized through improving the techniques of framework fabrication and winding.Finally,the outlook and error analysis of this kind of SC magnet coil are also discussed briefly.