智能增益修正改进电控柴油机调速性能的研究

很好地兼顾动、稳态调速性能是柴油机调速系统设计的重要目标,在数字调速系统中,采用非线性变增益和动态增益修正法,可使柴油机在各种工况下均具有良好的调速性能指标.文章介绍了这两种方法的基本原理、实现方法和试验结果.     

增益可调的高性能低噪声放大器的设计与实现

针对低噪声放大器实际工程中噪声、线性和匹配等性能要求,通过使用射频电路CAD软件先进设计系统(ADS)进行完整的分析,设计并实现了增益可调、噪声系数低、高线性度和可靠性高的低噪声放大器.     

不对称信息理论在船舶运动控制中的应用

本文介绍了不对称信息理论，并针对舵阻摇控制系统，通过简化鲁棒控制算法和改进舵机执行机构性能，增加信息的传递量，在提高系统鲁棒性能的基础上，使该算法成为实际工程上可用的算法。闭环增益成形算法采用闭环系统中具有工程意义的参数直接构造出鲁棒控制器，其设计过程简单，且物理意义明晰。从仿真结果可以看出：当信息传递充分时，航向保持效果大大改善，打舵的频率和幅值明显降低，同时也较为节能。     

公路货运超限治理中的利益博弈分析

通过对公路货运中政府、道路运营者、运输商及其后相关利益关系进行分析,按现有环境下管理方与运输商之间超限运输治理的博弈,提出超限治理过程中对治理策略的选择应着力降低治理成本,这有助于提高管理方的治理激励.     

Intelligent VIV control of 2DOF sprung cylinder in laminar shear-thinning and shear-thickening cross-flow based on self-tuning fuzzy PID algorithm

A self-tuning fuzzy PID (ST-FPID) control scheme is implemented within a joint interactive (Matlab/Simulink/Fluent) co-simulation framework for effective two degrees of freedom (2DOF) vortex-induced vibration (VIV) control of an elastically-mounted circular cylinder in laminar cross-flow of incompressible non-Newtonian power-law fluids based on the control action of a single transverse force actuator. The model-free controller, which systematically tunes the control parameters online in real time based on given rules, is well-known to be highly advantageous over the previously employed conventional PID controllers. It is particularly capable of handling the intricate non-linear dynamic effects inherent in the complex fluid rheology of non-Newtonian flow past the cylinder in presence of unmodeled system dynamics, high parametric uncertainties, diverse operational conditions, and time-varying external disturbances and control signals. Extensive numerical simulations reveal that the complex shear-thinning and shear-thickening behaviors of fluid viscosity can substantially influence the cylinder dynamic response, applied hydrodynamic forces, and flow structure. In particular, effectiveness and high performance of the adopted ST-FPID control strategy in substantial suppression of the high amplitude coupled 2DOF VIV of the elastically-mounted cylinder at selected critical reduced velocities in the lock-in region are established for a wide range of power-law index parameters (e.g., up to 83% reduction in RMS value of cylinder cross-flow displacement and up to 35% reduction in RMS value of cylinder in-line displacement for n=1and U* = 5 at Re = 100). Also, the vigorous action of the error-driven ST-FPID controller in forcing the high strength vortex shedding patterns of the uncontrolled cylinder out of the lock-in condition into the classical von Kármán vortex street of 2S-type mode of moderately weaker strengths is verified.     

恒增益旁瓣对消技术

在旁瓣对消系统中,当辅助天线数目大于干扰源数目时,期望信号也被当成一个干扰源而被系统对消掉。一般采用在辅助通道添加阻塞矩阵的方法来解决此问题。然而当期望信号方向与干扰信号方向接近时,采用阻塞矩阵方法会导致合成方向图有较大旁瓣抬升。提出一种新方法,对辅助天线的输出进行线性约束,使辅助天线在期望信号方向形成零陷,从而有效消除辅助通道的期望信号成分,并且具有较好的旁瓣保形能力。通过仿真可以看出,该方法能在保持期望信号方向最大增益的同时,在干扰方向形成非常理想的零陷。     

Automatic guidance control of an articulated all-wheel-steered vehicle

This paper presents automatic guidance control of a single-articulated all-wheel-steered vehicle being developed by the Korea Railroad Research Institute. The vehicle has an independent drive motor on each wheel except for the front axle. The guidance controller is designed so that the vehicle follows the given reference path within permissible lateral deviations. We use a three-input/three-output linearised model derived from the nonlinear dynamic model of the vehicle. For the purpose of simplifying the controller and making it tunable, we consider a decentralised control configuration. We first design a second-order decoupling compensator for the two-input/two-output system that is strongly coupled and then design a first-order controller for each decoupled feedback loop by using the characteristic ratio assignment method. The simulation results for the nonlinear dynamic model indicate that the proposed control configuration successfully achieves the design objectives.     

基于闭环增益成形的鲁棒PID算法及在液位控制中的应用

基于闭环增益成形算法给出鲁棒 PID算法 ,并将之应用于水箱液位的控制中。比较本文鲁棒 PID算法和文献 [1 ]模糊控制算法的仿真结果 ,得出前者的控制性能优于后者 ,同时具有良好的鲁棒稳定性。本文提出的鲁棒 PID算法简单、实用。     

Study on fast calibration of a ULA＇s gain and phase error

Array calibration is important in engineering practice. In this paper, fast calibration methods for a ULA＇s gain and phase errors both in far and near fields are proposed. In the far field, using a single sound source without exact orientation, this method horizontally rotates the array exactly once, performs eigen value decomposition for the covariance matrix of received data, then computes the gain and phase error according to the formulas. In the near field, using the same single sound source, it is necessary to rotate the array horizontally at most three times, build equations according to geometric relations, then solve them. Using the formula proposed in this paper, spherical waves are modified into plane waves. Then eigen values decomposition is performed. These two calibration methods were shown to be valid by simulation and are fast, accurate and easy to use. Finally, an analysis of factors influencing estimation precision is given.     

基于改进小波神经网络的集装箱船纵摇角度预测

为了解决船舶在海上航行时控制器舵角输出大、打舵频率高、控制速度较慢以及控制精度较低的问题,利用三阶闭环增益成形算法设计鲁棒控制器。

首先,利用三阶闭环增益成形算法设计出线性鲁棒控制器,然后,在控制策略中加入双曲正切非线性修饰以及零阶保持器,在不同海况下对该控制器的性能进行仿真实验。

仿真结果表明,相比于基于非线性修饰的传统PID控制器,在一般海况下,所提控制器在延迟时间、控制精度以及能量输出上分别改进了36%,14%和32%;在恶劣海况下,分别改进了27%,7%和16%。此外,不同海况下该控制器的仿真结果都具有稳定的舵角输出,并可以较快地稳定在临界值附近,证明了其具有较好的鲁棒性。

改进的控制器符合工程实践,对于智能船舶的控制具有较好的应用参考价值。