检索结果-南通市图书馆

Observer-based Adaptive optimal control for Unknown Singularly Perturbed Nonlinear systems With Input Constraints

在线全文

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2017年第1期4卷 48-57页

作者： Zhijun Fu Wenfang Xie Subhash Rakheja Jing Na College of Mechanical Engineering Zhejiang University of Technology Department of Mechanical & Industrial Engineering Concordia University Faculty of Mechanical & Electrical Engineering Kunming University of Science & Technology

This paper introduces an observer-based adaptive optimal control method for unknown singularly perturbed nonlinear systems with input constraints. First, a multi-Time scales dynamic neural network MTSDNN observer with a novel updating law derived from a properly designed Lyapunov function is proposed to estimate the system states. Then, an adaptive learning rule driven by the critic NN weight error is presented for the critic NN, which is used to approximate the optimal cost function. Finally, the optimal control action is calculated by online solving the Hamilton-Jacobi-Bellman HJB equation associated with the MTSDNN observer and critic NN. The stability of the overall closed-loop system consisting of the MTSDNN observer, the critic NN and the optimal control action is proved. The proposed observer-based optimal control approach has an essential advantage that the system dynamics are not needed for implementation, and only the measured input U+002F output data is needed. Moreover, the proposed optimal control design takes the input constraints into consideration and thus can overcome the restriction of actuator saturation. Simulation results are presented to confirm the validity of the investigated approach. © 2014 Chinese Association of Automation.

关键词： Closed loop systems Cost functions Lyapunov functions Neural networks Nonlinear systems optimal control systems Perturbation techniques

Neuro-optimal Guidance control for Lunar Soft Landing

在线全文

学校读者我要写书评

暂无评论

Journal of systems Engineering and Electronics 1999年第3期10卷 22-31页

作者： Wang, Dayi Li, Tieshou Yan, Hui Ma, Xingrui Harbin Inst of Technology Harbin China

Returning to moon has become a top topic recently. Many studies have shown that soft landing is a challenging problem in lunar exploration. The lunar soft landing in this paper begins from a 100 km circular lunar parking orbit. Once the landing area has been selected and it is time to deorbit for landing, a ΔV burn of 19.4 m/s is performed to establish a 100×15 km elliptical orbit. At perilune, the landing jets are ignited, and a propulsive landing is performed. A guidance and control scheme for lunar soft landing is proposed in the paper, which combines optimal theory with nonlinear neuro-control. Basically, an optimal nonlinear control law based on artificial neural network is presented, on the basis of the optimum trajectory from perilune to lunar surface in terms of Pontryagin's maximum principle according to the terminal boundary conditions and performance index. Therefore some optimal control laws can be carried out in the soft landing system due to the nonlinear mapping function of the neural network. The feasibility and validity of the control laws are verified in a simulation experiment.

关键词： Boundary conditions Computer simulation control system analysis control system synthesis Functions Lunar landing Lunar missions Maximum principle Neural networks Nonlinear control systems optimal control systems Orbits

On the Solutions of the Matrix Equations in optimal Stochastic control

在线全文

学校读者我要写书评

暂无评论

Journal of systems Engineering and Electronics 1999年第3期10卷 38-43页

作者： Deng, Feiqi Hu, Gang Liu, Yongqing Feng, Zhaoshu South China Univ of Technology Guangzhou China

In this paper, the matrix algebraic equations involved in the optimal control problem of time-invariant linear Ito stochastic systems, named Riccati- Ito equations in the paper, are investigated. The necessary and sufficient condition for the existence of positive definite solutions of the Riccati- Ito equations is obtained and an iterative solution to the Riccati- Ito equations is also given in the paper thus a complete solution to the basic problem of optimal control of time-invariant linear Ito stochastic systems is then obtained. An example is given at the end of the paper to illustrate the application of the result of the paper.

关键词： Computational methods control system analysis control system synthesis Iterative methods Linear control systems Matrix algebra optimal control systems Riccati equations

optimal control and Output Feedback Considerations for Missile with Blended Aero-fin and Lateral Impulsive Thrust

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2010年第4期23卷 401-408页

作者：邢立旦张科南陈万春殷兴良北京航空航天大学宇航学院航天飞行器技术系中国航天科工集团

For the missile with blended aero-fin and lateral impulsive thrust, a blended control autopilot is designed, which comprises an optimal controller and a control allocation module. The combined optimal/classical approach is applied to designing the optimal controller to determine the virtual controls, and the control allocation module is used to distribute the desired vitlual controls onto the redundant control effectors. The autopilot holds some attractive characteristics, such as simple structure, good tracking performance and robustness; moreover the actual constraints of the control effectors can be taken into account. Based on this blended control autopilot, it is found that the conflict between stability and fast tracking performance is serious when using the total acceleration as feedback. In order to avoid this problem, the transient factors in total acceleration are eliminated, so the acceleration caused only by angle of attack is used as feedback, and obvious improvement is shown. Finally, how to get reasonable acceleration feedback is discussed, and conclusion is presented that after passing the low-pass filter, the total acceleration can also be used as feedback, and satisfied tracking performance can be obtained.

关键词： missiles optimal control systems feedback control blending control lateral thrust

Optimization of projectile state and trajectory of reentry body considering attainment of carrying aircraft

在线全文

学校读者我要写书评

暂无评论

Journal of systems Engineering and Electronics 2017年第1期28卷 137-144页

作者： Changsheng Gao Chunwang Jiang Wuxing Jing School of Astronautics Harbin Institute of TechnologyHarbin 150001China

As an improvement of traditional maximum range trajectory optimization, both the projectile state and control sequence of reentry body are optimized to achieve the maximum range. To ensure the optimal projectile state is in the reachable domain of the carrying aircraft, the climb of the carrying aircraft and the flight of reentry body are optimized as a whole based on the hp-adaptive pseudospectral method. Meanwhile, the path constraints, control constraints and initial/terminal states constraints are considered in the optimization as well. In face of the fact that the range of the optimal control solution resulted from the pseudospectral method may be unsmooth, virtual control variables (second derivatives of the angle of attack and bank angle) are proposed in the optimization, while the angle of attack and bank angle are treated as the virtual state variables to guarantee the smoothness of the optimal control solution. The validity of the virtual control variables in smoothing the optimal control solution is verified by simulation, and the optimality of the resulting projectile state and control sequence for reaching the maximum range is confirmed using the indirect approach. © 1990-2011 Beijing Institute of Aerospace Information.

关键词： Aerodynamics Angle of attack optimal control systems Projectiles

STUDY OF optimal SLIDING-MODE GUIDANCE LAW

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 1999年第4期12卷 236-241页

作者：周荻慕春棣凌强徐文立哈尔滨工业大学控制工程系黑龙江哈尔滨清华大学自动化系北京

An optimal guidance law based on missile-target line-of-sight (LOS) angular rate is presented for intercepting a nonmaneuvering target. It is then integrated with sliding-mode control theory by using reaching-law of sliding-mode, in order to derive an optimal sliding-mode guidance law for intercepting a maneuvering target. The new guidance method's robustness against target maneuvers and good miss distance performance are proved by the second method of Lyapunov and simulation results. The presented guidance law is simple to implement in practical applications.

关键词： Computer simulation Electronic guidance systems Lyapunov methods optimal control systems Robustness (control systems)

RESEARCH OF THE SWITCHED RELUCTANCE STARTER/GENERATOR systems

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 1999年第4期12卷 222-226页

作者：李磊朱学忠曹志亮南京航空航天大学303实验室江苏南京

This paper focuses on the simulation and test of the switched reluctance starter/generator systems. Through the emulational analysis of the initial starting torque, the optimal turn-on section of the power switches is discovered. The fundamental theory of the generating operation is analyzed with the linearity model, and a new method is presented based on voltage pulse width modulation for the generating mode control. Through the steady-state and optimized emulation of the output power and system efficiency, the optimizational control approach for the generating mode over a wide speed range is introduced. At last, the test of the 3KW prototype system shows that the dynamic and static performance of this system is fine.

关键词： Electric generators Linearization Mathematical models optimal control systems Pulse width modulation Reluctance motors Starters

NUMERICAL MODEL FOR DYNAMIC SIMULATION OF TRAFFIC FLOW

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 1994年第1期6卷 1-11页

作者： Wu, Zheng Zeng, Linong Fudan Univ Shanghai China

For the purpose of practical application in traffic engineering, especially in automatic control of traffic systems, in this paper a numerical model for the dynamic simulation of traffic flow was presented, involving difference schemes, boundary conditions and their discrete forms, expressions of traffic behavior parameters and technique of modelling parameter identification. The analysis of numerical simulation for several realistic examples shows the usefulness and advantages of the model.

关键词： Computer simulation Finite difference method Mathematical models optimal control systems Traffic control Traffic surveys