基于滑模自抗扰的永磁同步电机控制

针对基于自抗扰原理的永磁同步电机控制存在待整参数多和参数物理意义不明显等问题,提出一种改进滑模自抗扰控制算法。首先,利用滑模趋近律构建出最优控制函数,将扩张状态观测器及非线性误差反馈控制律中的fal函数用最优控制函数代替,从而减少待整参数,完成对非线性自抗扰控制器结构的优化。其次,使用李雅普诺夫函数对改进滑模自抗扰控制器的稳定性进行分析。最后,采用Matlab仿真验证该算法的可行性。仿真结果表明:永磁同步电机调速系统采用改进滑模自抗扰控制器后,既能保留非线性自抗扰法无超调起动和抗负载扰动能力强的优点,又能提高永磁同步电机调速系统的动态稳态性能。

Experimental study on the pressure control of soil chamber in shield tunneling

A mathematical model of the soil pressure system in shield tunneling was proposed to optimize soil pressure control in the soil chamber, based on the constitutive relationship between strain and stress. The desired pressure is determined by using the finite element method. A linear quadratic constant state tracking problem was considered over an infinite time interval. The optimal control law was derived by differentiating the Hamilton function with respect to system input. In order to verify the effectiveness of the proposed mathematical model and optimal control law, an experimental study on the pressure control of the soil chamber in shield tunneling was conducted in a laboratory. The experiment results show that soil pressure in the soil chamber in shield tunneling can be accurately controlled.

A New Optimal Control System Design for Chemical Processes

Based on frequency response and convex optimization,a novel optimal control system was developed for chemical processes.The feedforward control is designed to improve the tracking performance of closed loop chemical systems.The parametric model is not required because the system directly utilizes the frequency response of the loop transfer function,which can be measured accurately.In particular,the extremal values of magnitude and phase can be solved according to constrained quadratic programming optimizer and convex optimization.Simulation examples show the effectiveness of the method.The design method is simple and easily adopted in chemical industry.

Constitution of Hamiltonian Function and Solution of Optimal Control of a Sort of Performance Index

Hamiltonian function is firstly constituted for solving optimal control. When character of controlled object is known,Hamiltonian function is determined by performance index. In this paper,by constituting Hamiltonian function and solving optimal control of a sort of performance index,we can understand optimal control theory and apply optimal control method better.

Robust Adaptive Control of PVTOL System via Minimum Projection Method

＂Dynamic extension＂ is commonly used for stabilization of the planar vertical take off and landing （PVTOL） system. Most controllers designed by the method are based on ＂dynamic＂ control Lyapunov functions （CLFs）. We design a C^∞ differentiable ＂static＂ CLF for the PVTOL system by dynamic extension and minimum projection method. Then we propose an inverse optimal controller based on the static CLF that attains a gain margin. We design an adaptive control input and show the robustness of the controller by computer simulation.

Bellman Equation for Optimal Processes with Nonlinear Multi-Parametric Binary Dynamic System

A process represented by nonlinear multi-parametric binary dynamic system is investigated in this work. This process is characterized by the pseudo Boolean objective functional. Since the transfer functions on the process are Boolean functions, the optimal control problem related to the process can be solved by relating between the transfer functions and the objective functional. An analogue of Bellman function for the optimal control problem mentioned is defined and consequently suitable Bellman equation is constructed.

智能化建筑室内外照明设备的节能与优化

传统节能与优化方法无法实现对灯具光照度的调节控制,为了解决这一问题,提出智能化建筑室内外照明设备的节能与优化。先分析智能化建筑室内外照明需求,再运用系数法求得对应系数。为求出优化控制目标函数,运用哈密顿函数求得三项系数在控制约束条件下最优控制率。在完成上述计算后,利用逐点计算法,得到灯具不同安装形式照度总和。在外部条件单一变量基础上,完成节能与优化流程设计。由此,完成智能化建筑室内外照明设备的节能与优化方法设计。实验选择在某建筑中完成,分别测试两种方法灯具光照度调节控制情况,实验结果表明,采用所提方法对建筑改造后的节能耗量一直维持在5700°左右,相比改造前节耗量少100多度。由此,证明所提方法更符合设计需求。

A Markov decision problem in a risk model with interest rate and Markovian environment

We consider the compound binomial model in a Markovian environment presented by Cossette et al.(2004). We modify the model via assuming that the company receives interest on the surplus and a positive real-valued premium per unit time, and introducing a control strategy of periodic dividend payments. A Markov decision problem arises and the control objective is to maximize the cumulative expected discounted dividends paid to the shareholders until ruin minus a discounted penalty for ruin. We show that under the absence of a ceiling of dividend rates the optimal strategy is a conditional band strategy given the current state of the environment process. Under the presence of a ceiling for dividend rates, the character of the optimal control strategy is given. In addition, we offer an algorithm for the optimal strategy and the optimal value function.Numerical results are provided to illustrate the algorithm and the impact of the penalty.

FINITE ELEMENT APPROXIMATION FOR A CLASS OF PARAMETER ESTIMATION PROBLEMS

This paper investigates the finite element approximation of a class of parameter estimation problems which is the form of performance as the optimal control problems governed by bilinear parabolic equations,where the state and co-state are discretized by piecewise linear functions and control is approximated by piecewise constant functions.The authors derive some a priori error estimates for both the control and state approximations.Finally,the numerical experiments verify the theoretical results.