一类自适应预测控制方法及在电液比例控制中的应用

为电液比例系统提供了一个输入输出增量式线性时变模型，采用加权限定记忆回归法来估计模型参数，在此基础上进而提出了一种自适应预测控制方法，并给出了最优控制律，仿真结果表明了该线性时变模型和参数估计算法的可行性，表明该自适应预测控制方法具有优良的控制品质。     

基于ESO的电液位置伺服系统自适应反步滑模控制

针对阀控电液位置伺服系统具有的不确定参数、外部干扰、系统状态不可测问题,在反步控制的基础上,同时引入滑模控制理论,提出一种带有ESO(扩展状态观测器)的自适应反步滑模控制策略。建立系统的非线性状态空间方程,基于系统模型设计出一种ESO,对速度值以及外干扰进行有效估计,同时引入自适应算法对系统不确定参数进行在线估计,设计出不确定参数的自适应律,通过Lyapunov稳定性定理证明所设计的控制器的稳定性。最后,仿真研究表明所设计的控制器能够对速度以及外干扰进行有效估计,并且具有较高品质的位置跟踪能力。     

含死区输入电液系统的模型参考滑模控制

针对含死区输入非线性电液速度伺服系统的跟踪控制问题,结合模型参考与滑模变结构控制理论,提出一种自适应模型参考滑模控制方案.用模型参考方法来保证系统的稳态品质,用滑模控制方法来改变系统的动态品质,利用对称型Sigmoid连续函数以平滑不连续控制.仿真结果显示,该方案可以减小跟踪误差、增强系统的鲁棒性和削弱控制信号中的高频抖振.     

弹丸协调器电液系统的参数自适应反演控制

针对存在参数不确定性和非线性的弹丸协调器电液伺服系统模型,结合反演控制设计方法和自适应控制方法,提出一种参数自适应反演控制算法。采用反演控制设计方法推导非线性系统的控制律,结合Lyapunov定理保证闭环系统全局稳定。针对模型的不确定参数,通过构建不连续映射自适应律进行精确估计,解决系统模型不确定性问题,简化控制算法的设计。引入鲁棒项,提高系统稳定性。仿真结果表明:所设计算法是有效的,与PID算法相比有更好的控制效果。     

并联坐标测量机神经网络滑模控制

研究了6-TPS型并联坐标测量机的基于RBF神经网络的直接自适应滑模控制方法.根据测量机的系统动力学模型特点,基于Lyapunov函数的综合设计方法和滑模控制理论,利用RBF神经网络与自适应技术相结合,设计了一种控制律,然后利用MATLAB进行了系统控制仿真.结果表明,测量机在有周期干扰的情况下,采用这种直接自适应神经网络滑模控制方法达到了较高的控制精度,其闭环系统具有较强的自适应性和鲁棒稳定性.     

动压缸电液伺服压力系统自适应反步双滑模控制

给出了轨道路基测试装置液压原理图、动压缸电液伺服压力系统数学模型和AMESim模型。将动压缸电液伺服压力系统拆分为动压缸位移子系统和动压缸输出压力子系统两部分,在此基础上,设计了一种自适应反步滑模控制方法:采用双滑模结构,分别构造动压缸位移子系统滑模自适应控制和动压缸输出压力子系统反步滑模自适应控制,给出了不确定参数的自适应律,并对该方法的稳定性进行了证明。最后将该方法作用于动压缸电液伺服压力系统AMESim模型上,仿真结果表明:该方法不仅可以有效地估计系统中参数,实现对目标期望变量精确地跟踪,具有比积分滑模自适应控制(ISAC)更好的控制性能和跟踪性能;而且可以有效地减小参数不确定性对跟踪性能的影响,具有较好的鲁棒性能。     

电液力伺服系统的模型参考自适应控制

本文基于李亚普诺夫稳定性理论,提出了一种参数补偿的模型参考自适应控制系统。这种自适应控制算法无需辨识系统的全部状态变量,只需系统的输入和输出就可综合出自适应律,使系统自动地按照参考模型的性能进行控制,并在板簧试验电液力伺服系统中得到成功的应用。     

基于MRAS技术在永磁同步电机控制中的应用

论文对基于无传感器MRAS技术在永磁同步电机控制系统中的应用进行阐述.以永磁同步电机的数学模型作为出发点,电机的转速为可调参数,通过电机的电流模型建立参考模型与可调模型.通过两个模型输出量的差值设计合适的自适应律来实时调节可调模型的待估参数,达到可调模型跟踪参考模型的目的.并根据超稳定性理论来保证系统和速度的渐进收敛性.在MATLAB/Simulink环境下实现基于MRAS技术永磁同步电机直接转矩控制系统的仿真.仿真结果表明,能够准确估计转子的速度和位置,系统具有较好的鲁棒性.     

直线电机进给系统摩擦自适应补偿控制北大核心

为消除非线性摩擦干扰对直线电机进给系统定位精度的不利影响,提出一种基于LuGre摩擦模型的自适应补偿控制方法。建立直线电机进给系统的动力学方程,并在系统建模中引入基于自适应因子的改进LuGre模型;采用反步设计法的思想,利用李雅普诺夫第二法推导了自适应控制律;最后进行了半物理仿真实验。仿真结果表明:该自适应控制器应用于直线电机进给系统的摩擦补偿是可行的,有效提高了系统的位移定位精度和速度跟踪精度。     

具有深度自适应估计的视觉伺服变结构控制

主要从控制的角度出发,考虑视觉伺服的具体问题, 利用变结构控制理论设计了摄像机的平移和旋转速度控制器,用自适应估计的方法对深度进行估计,给出深度变化趋势,基于图像误差实现定位控制,能够确保系统全局渐近可稳定性.该方法不需要物体的几何模型及深度的精确值,仅需要物体初始及期望位置的深度估计值.仿真结果表明该方法是有效的.     

一种用于永磁同步电机无速度传感器控制系统的转速辨识复合算法

本文针对永磁同步电机控制系统,提出了一种将模型参考自适应(MARS)转速辨识算法与直接估算转速算法相结合的转速辨识复合算法,并构建了复合仿真模型。结果表明,采用复合算法的系统性能优于只采用单一的MARS转速辨识算法的系统性能。     

PMSM分数阶滑模变结构MRAS仿真

针对永磁同步电机(PMSM)模型参考自适应控制系统(MRAS)中存在的抖振及转速估计精度低的问题,提出了一种分数阶滑模变结构MRAS转速辨识方法。首先建立了PMSM的参考模型和可调模型,利用参考模型和可调模型的电流输出误差来构造分数阶滑模面,其次设计了电机速度观测器,用Lyapunov稳定性理论证明了其可行性。最后利用MATLAB/SIMULINK软件搭建仿真模型进行仿真。仿真结果验证了PMSM分数阶滑模变结构速度观测器的有效性,具有更加精确地对转速进行跟踪的能力,有较好的鲁棒性。     

Virtual CNC system. Part I. System architecture

The paper presents a comprehensive virtual simulation model of a realistic and modular CNC system. The Virtual CNC architecture represents an actual CNC, but with modular feed drives, sensors, motors, and amplifiers. The CNC software library includes a variety of trajectory interpolation and axis control laws. Constant, trapezoidal and cubic acceleration profiles can be selected as a trajectory generation module. The control laws can be selected ranging from a simple PID to complex Pole Placement, Generalized Predictive Control or Sliding Mode Controller with friction compensation. When the Virtual CNC is assembled, its performance can be tested using frequency and time domain response analyses, which are automated. The Virtual CNC includes both analytical tuning methods for linear controllers, as well as Fuzzy Logic based expert auto-tuning system for Adaptive Sliding Mode Control. The paper includes detailed experimental verification of the Virtual CNC.     

基于MATLAB的并联机器人ISMVSC轨迹跟踪控制研究

主要介绍了积分滑模变结构控制（ISMVSC）在并联机器人控制系统中的应用。在传统变结构理论的基础上。提出一种以趋近率设计的ISMVSC模型跟踪控制策略，并将此理论应用于两自由度并联机器人轨迹跟踪控制系统。基于MATLAB／SIMULINK进行动态仿真，仿真结果表明：ISMVSC控制策略对外部干扰及参数变化具有较强的鲁棒性，其良好的跟踪性能可实现并联机器人的高精度控制。     

基于混合编程和结合特征提取方法的转辙机故障诊断系统开发

针对基于EMD、WPT的特征提取方法各自存在的问题,采用将EMD与WPT结合的信号分解方法用于包络特征的提取,保证信号的分解不仅具有较高的分辨率,并且能够避免虚假IMF分量带来的错误信息。在包络特征的提取及结合之后,采用了基于PCA的特征选择方法对缺陷信号的特征数据集进行最有效特征的分类识别。根据以上特征提取及识别方法,使用Matlab以及Labview的混合编程进行了面向S700K-C型电动转辙机的故障诊断系统操作,并通过应用试验证明了该系统能够准确、快速地提取出故障信号。     

Predictions on surface finish in electrical discharge machining based upon neural network models

Predictions on the surface finish of work-pieces in electrical discharge machining (EDM) based upon physical or empirical models have been reported in the past years. However, when the change of electrode polarity has been considered, very few models have given reliable predictions. In this study, the comparisons on predictions of surface finish for various work materials with the change of electrode polarity based upon six different neural-networks models and a neuro-fuzzy network model have been illustrated. The neural-network models are the Logistic Sigmoid Multi-layered Perceptron (LOGMLP), the Hyperbolic Tangent Sigmoid Multi-layered Perceptron (TANMLP), the Fast Error Back-propagation Hyperbolic Tangent Multi-layered Perceptron (Error TANMLP), the Radial Basis Function Networks (RBFN), the Adaptive Hyperbolic Tangent Sigmoid Multi-layered Perceptron, and the Adaptive Radial Basis Function Networks. The neuro-fuzzy network is the Adaptive Neuro-Fuzzy Inference System (ANFIS). Being trained by experimental data initially screened by the Design of Experiment (DOE) method, the parameters of the above models have been optimally determined for predictions. Based upon the conclusive results from the comparisons on checking errors among these prediction models, the TANMLP, RBFN, Adaptive RBFN, and ANFIS model have shown consistent results. Also, it is concluded that the further experimental results have agreed to the predictions based upon the above four models.     

数控永磁同步电动机自适应模糊滑模PI控制策略研究

永磁同步电动机是一个多变量、非线性、强耦合对象.在综合比较自适应控制、模糊控制、滑模变结构控制的优点的基础上,提出了一种自适应模糊滑模PI控制策略.滑模变结构控制具有强大的对系统参数变化和外部扰动良好的鲁棒性的能力,自适应模糊PI控制逼近非连续控制,削弱抖振,同时保证系统渐进稳定.仿真结果验证了所提出的控制策略的有效性.     

Rapid identification technique for virtual CNC drives

This paper presents a technique for rapid identification of machine tool drives by conducting a short G-code test. The proposed strategy uses commanded and measured axis profiles and requires minimal intervention to the servo control loop. The drive system is identified as a whole, including the feed mechanism, motor, amplifier, and the control law. The methodology is fairly general and applicable to linear or ball screw drives, controlled with commonly used controllers like P, PI, PID, P–PI Cascade or Adaptive Sliding Mode Control; with or without feedforward dynamic or friction compensation. In order to guarantee the stability of identified dynamics, bounds are imposed on the pole locations. The identified models can be used in a Virtual CNC system for predicting the contouring and tracking errors to different part programs. Simulation and experimental case studies are presented, where tracking and contour errors are successfully predicted using drive models identified with the proposed strategy.     

Interacting mechanism and initiation prediction of multiple cracks

The maximum Mode I and Mode II stress intensity factors (SIFs), K_I,kmax(θ) and K_II,kmax(θ) (0°<θ<360°), of inclined parallel multi-crack varying with relative positions (including horizontal and vertical spacings) are calculated by the complex function and integration method to analyze their interacting mechanism and determine the strengthening and weakening zone of SIFs. The multi-crack initiation criterion is established based on the ratio of maximum tension?shear SIF to predict crack initiation angle, load, and mechanism. The results show that multi-crack always initiates in Mode I and the vertical spacing is better not to be times of half crack-length for crack-arrest, which is in good agreement with test results of the red-sandstone cube specimens with three parallel cracks under uniaxial compression. This can prove the validity of the multi-crack initiation criterion.     

The VSS controller design and implementation for the constant turning force adaptive control system

Although the Constant Turning Force Adaptive Control (CTF AC) system has been developed for many years, the control stability during cutting a workpiece at varied cutting depth is still a reliability problem. In this paper, we propose a new variable structure system (VSS) approach to adjust controller gain according to the sliding mode with high robustness in order to stabilize the CTF AC system against the nonlinear time-varying gain perturbation in the cutting process. A simple control algorithm of the VSS controller will be presented and several illustrative simulation results given. According to the practical experimental results of a converted lathe with the CTF AC system, this VSS controller is capable of good performance and good reliability.