输入受限线性系统鲁棒抗饱和控制

针对抗饱和控制的鲁棒性问题,将研究扩展到对输入饱和非线性、时变参数和动态不确定性具有结构摄动的鲁棒性框架内,给出了一种线性时不变系统鲁棒抗饱和控制算法.鉴于积分二次型约束具有刻画结构不确定性的能力,选择在积分二次型约束框架下解决问题.以定标的线性矩阵不等式形式给出了系统分析和控制综合条件.飞行控制仿真结果说明此算法不仅可以成功克服饱和非线性,且对时变参数和动态不确定性具有良好的鲁棒性.     

Recurrent Neural Network based Soft Sensor for flow estimation in Liquid Rocket Engine Injector calibration

Injector is the critical element in the Liquid Rocket Engine (LRE), to ensure proper mixing of propellants (fuel and oxidizer) in the thrust chamber for achieving the optimum thrust. LRE injector is calibrated in order to deliver required flow rates of propellants by sizing the orifices through simple injector water calibration (IWC) techniques. In LRE-IWC process, a huge 6” turbine flow meter (TFM) is employed for the flow-rate measurement. In order to achieve and maintain the required accuracy and precision in the LRE-IWC process, periodical calibration of TFM is mandatory. It involves tremendous time, cost and human effort. Soft sensors can provide an economical and effective alternative solution for TFM flow-rate measurement. The objective of the proposed work is to develop and implement a recurrent neural network based soft sensor (RNN-SS) for TFM flow-rate measurement. In the LRE-IWC process, experimental flow trials were carried out for different flow patterns, and the necessary measurement data were generated for the soft sensor design. The designed RNN-SS was trained by tuning various hyper parameters to replace the TFM, using three related measurement parameters acquired during the experimental trials. The precise TFM flow-rate estimation was achieved by the designed RNN-SS, with a worst-case mean absolute percentage error (MAPE) of 1.91% for the experimental flow patterns considered, with good repeat-ability. The proposed RNN-SS model for TFM flow-rate estimation gives a MAPE of 0.58%, for the required flow-pattern which is well suited for practical use.     

Particle Swarm Optimization Applied to Some Anti-Windup Problems

The particle swarm optimization (PSO) algorithm is introduced to deal with some open anti-windup problems, i.e., determining the initial condition when applying the iterative algorithm to enlarge the estimate of the domain of attraction, determining the design point in the delayed anti-windup scheme, and determining the design point and the weighting factors in the multi-stage anti-windup scheme. Therefore, the corresponding PSO-based algorithms are proposed. Unlike the traditional methods in which the free design parameters can only be selected by trial and error with the available computational results, the PSO-based algorithms provide a systematic way to determine these parameters. In addition, the algorithms are easy to be implemented and are very likely to find the desirable parameters that further improve the anti-windup closed-loop performances. Simulation results are presented to validate the effectiveness and advantages of the proposed method.     

高阶非线性系统状态反馈抗饱和跟踪控制

针对参数未知的高阶非线性系统,提出了一种简单有效的反馈抗饱和控制方法,并进行了状态反馈抗饱和控制吸引域估计.利用反馈控制思想,借助于李亚普诺夫稳定性理论,设计出了相应的状态抗饱和反馈控制器,并借助于Matlab进一步求出了控制器的参数.将所设计的抗饱和控制应用于Duffing混沌系统,仿真结果验证了该控制方法的有效性.     

具有不确定雅可比矩阵机器人的鲁棒非线性PID控制器的抗饱和失效设计

对于雅克比阵不确定的操作机器人笛卡尔空间操作任务, 提出一种鲁棒非线性PID控制器的抗饱和设计方案, 解决了PID控制中的积分饱和问题. 该控制器通过引入有界递增分段连续函数于PID控制器中的积分环节, 限制了积分器的积分作用, 从而克服了积分环节对闭环系统的不利影响: 一方面使得闭环系统是渐进稳定的, 另一方面又保证了其鲁棒性; 特别是, 相比于其它的抗饱和设计方法, 显得更加简单有效.     

On the phase-plane analysis of relay control system with dead time†

An exact method of analysis of non-linear systems containing a two-position relay element and a dead-time element is given using the phase-plane concept. Equations of the switching lines for both unsymmetrical and symmetrical relay characteristics are obtained under consideration of the dead time. Expressions to evaluate the period and amplitude of the self-oscillation of the system are derived from the stable limit cycle in the phase plane.

This method is developed for a second-order system with a zero in its transfer function. For such a system it is indicated with a help of an example that approximation methods as the describing function yield large errors because the low-pass condition is not satisfied. The phase-plane method will be developed for other relay characteristics.     

Anti-windup strategies for discrete-time switched systems subject to input saturation

This paper deals with the design of anti-windup compensator for discrete-time switched systems subject to input saturation. The cases of static and dynamic anti-windup controllers are addressed aiming at maximising the estimate of the basin of attraction of the origin for the closed-loop system. Two aspects of the switching law are taken into account during the design: either it is arbitrary or it is a part of the complete control law. Theoretical conditions allowing to synthesise the anti-windup compensator are mainly described through linear matrix inequalities. Computational oriented conditions are then provided to solve convex optimisation problems that are able to give a constructive solution.     

基于抗积分饱和速度调节器的TSMC-PMSM矢量控制

研究了双级矩阵变换器驱动的永磁同步电机(TSMC-PMSM)矢量控制系统。针对传统的PID速度调节器会产生积分windup现象,使系统产生超调和振荡问题,提出了基于抗积分饱和(anti-windup)速度调节器的TSMC-PMSM矢量控制方法。anti-windup控制策略能使速度调节器出现饱和时,快速退出饱和区。仿真结果表明,抗积分饱和速度调节器能有效抑制windup现象,减小系统的超调量,提高整个控制系统的稳定性。     

Stabilization of Large Power Systems Using VSC–HVDC and Fuzzy Anti-Windup Subject to Input Constraints

Abstract

This paper considers the robust stabilization problem for Takagi-Sugeno (TS) fuzzy systems subject to input saturation. The purpose is the design of fuzzy controllers based on fuzzy anti-windup ensuring convergence of all admissible initial states within the domain of attraction. The effectiveness of the proposed controller is demonstrated through two closed-connected High Voltage Direct Current (HVDC) lines studies using MATLAB/SIMULINK software package. The simulation results show that the proposed controller contribute significantly toward improving the damping behavior of the Voltage Source Converter (VSC)-HVDC system with regard to parameter variations and external load disturbances compared with alternative frameworks existing in the literature under a wide range of operating conditions.     

电动舵机伺服控制器的设计与研究

以TMS320F2812 DSP为核心,永磁同步电动机+滚珠丝杠为作动执行机构,采用id=0控制策略,结合空间矢量脉宽调制(SVPWM)技术,完成对舵机系统的矢量控制.针对机械谐振、力矩耦合及电气参数波动等非线性因素的影响,采用结合模糊控制规则的抗积分饱和PID控制器.实验结果表明,该系统具有控制精度高、响应速度快和跟踪能力强等特点.