带有应变反馈的柔性机械臂开关变结构控制的实验研究

为实时,有效地抑制柔性机械臂的残余振动,提高春定位精度,提出了柔性机械臂的开关变结构控制,并进行了实验研究,将柔性机械臂的运动分成两个阶段：第一阶段使其在控制力矩作用下做大角度刚体运动;第二阶段当柔性机械臂的运动临近终止状态时,通过逻辑开关,将柔性梁应变反馈量接通,以产生控制力矩,实现残余振动抑制,与传统的PID控制和带有应变反馈的全闭环反馈控制的比较结果显示,开关变结构控制能够有效,实时地抑制柔性残余振动。     

测试转台的状态反馈变结构控制

本文提出了一种融合了经典状态反馈控制和变结构控制的方法,该法同时具有状态反馈设计闭环动态的灵活性和变结构优良的鲁棒性。并将其应用于高精度测试转台,取得了良好的仿真效果。     

带有加速度反馈的柔性机械臂开关变结构控制的实验研究

为有效地抑制柔性机械臂的残余振动 ,提高其定位精度 ,本文提出了带有加速度反馈的柔性机械臂开关变结构控制 ,并进行了一系列系统的实验研究。首先将柔性机械臂的运动分成两个阶段 :第一阶段使其在控制力矩作用下做大角度刚体运动 ;第二阶段当柔性机械臂的运动临近终止状态时 ,通过逻辑开关 ,将柔性机械臂末端加速度反馈量接通 ,以产生抑制弹性振动的控制力矩 τ′0 ,实现终点定位的残余振动控制。然后进行了一系列的实验研究包括与传统的 PID控制和带有加速度反馈的全闭环反馈控制的比较 ,结果显示带有加速度反馈的柔性机械臂开关变结构控制能够实时、有效地抑制柔性臂的残余振动     

基于同位加速度负反馈的振动主动控制研究

基于同位加速度传感/压电驱动的反馈方法,对用扬声器进行声激励的四面固支铝板开展多模态振动主动控制研究。根据实验模态分析的结果,确定了传感和驱动的位置。经过压电片传感/压电片驱动和加速度传感/压电片驱动两种方案的对比,选择了能观性和能控性较好的加速度传感方式。在正位置反馈控制律（positive position feedback,简称PPF）的基础上,以加速度信号进行反馈控制律的设计,提出基于加速度负反馈控制方案 (negative acceleration feedback,简称NAF),并对其进行稳定性和控制机理分析。控制时以加速度信号作为评价指标,对64和158 Hz两个模态分别进行单模态和多模态控制。结果表明,基于加速度的反馈控制可以大幅度降低铝板的振动,最大控制效果可达11 dB,远大于PPF的控制效果,对单模态和多模态均能实现有效的振动控制。     

反馈信号的滞后对混沌控制的影响

针对Pyragas延时反馈控制方法和自适应延时反馈控制方法，研究反馈信号滞后对混沌控制效果的影响。以信号滞后时间τ0作为分岔参数，得到控制系统状态变量对τ0的分岔图，该图表明信号滞后对两种混沌控制方法的控制效果均有不同程度的影响。与Pyragas延时反馈控制方法相比，自适应延时反馈控制方法具有较强的鲁棒性。另外，该方法能够在较短的时间内将混沌系统稳定在期望的周期轨道上。     

板形自动控制在热连轧中的应用

莱钢1500热连轧生产线的板形自动控制系统是国内自主研发的板形控制系统,它包括板预设定形、板形的PID调节、弯辊力的前馈控制、凸度仪的反馈控制、窜辊的闭环调节、平坦度的反馈控制、板形与板厚的解耦控制等多种控制于一体。主要介绍弯辊力前馈、凸度反馈和平坦度反馈3个模型在实际轧钢过程中的应用。     

汽车发动机的变结构控制和智能控制方法研究

燃油控制和转速在汽车发动机控制中时十分重要的项目。发动机的工作性能受到发动机燃油控制质量的直接影响。为了使发动机排气清洁性、安全性、行驶性、输出功率、热效率等处于最佳状态,就应以更高的标准来提高发动机控制。     

横摆角速度反馈汽车转向控制的理论研究

从理论上研究了具有横摆角速度反馈特性的汽车转向控制系统,对横摆角速度反馈控制、一增益形式横摆角速度反馈控制进行了系统研究和综合比较,横摆角速度反馈不但使横摆角速度响应的带宽增大,而且同时使横摆角速度阻尼增大,产闰中车辆重心侧偏角的稳态增益和侧向加速度超调量,使得转向运动更加平稳、方向性得到一定程度的改善。另外,研究表明两种前轮转向控制方法对高速工况处的车辆和过度转向珠作用非常明显可以显著地提高车辆     

压电微夹钳的位移自感知反馈复合控制*

采用自感知方法获取压电微夹钳钳指位移,构成自感知反馈复合控制系统。根据反映钳指位移、表面电荷、夹持力、驱动电压之间关系的压电悬臂梁Smits方程,提出了基于电流积分的钳指位移自感知方法;引入死区算子对传统PI模型进行改进,建立了压电微夹钳钳指位移的迟滞模型;以对偏差的抛物线积分、对输出的先行微分分别代替常规PID控制器中的积分项和微分项,设计出了压电微夹钳的改进PID反馈控制器;将前馈控制器与PID反馈控制器相结合,并采用自感知反馈方式,设计出了压电微夹钳的闭环控制系统。实验结果表明:在自感知反馈复合控制作用下,压电微夹钳对5μm阶跃参考位移的响应时间为0.24 s,若不考虑噪声影响,稳态误差几乎为零;在最大位移为14.7μm的变幅值三角波参考位移以及最大位移为14.1μm的任意波形参考位移作用下,压电微夹钳的自感知反馈复合控制亦可取得良好的控制效果,其稳态误差中线在-0.02~0.04μm之间变化。自感知反馈控制的实验结果与传感器反馈控制基本相同,从而表明压电微夹钳的自感知反馈控制是有效的。     

Smith预估控制在冷带轧机液压AGC前馈-反馈控制系统中的应用

作为消除成品厚差的重要手段，液压AGC前馈．反馈控制系统对于提高板带材的成品精度起着至关重要的作用，但是采用机架后测厚仪进行反馈滞后大，系统稳定性变差，导致控制精度降低。因此，引入Smith预估控制与前馈．反馈控制系统相结合的办法来进行控制，并以某四辊可逆冷带轧机为对象进行仿真研究，取得了良好的效果，系统的控制精度和稳定性都有所提高。     

Non-singular terminal dynamic surface control based integrated guidance and control design and simulation

In this paper, a novel cascade type design model is transformed from the simulation model, which has a broader scope of application, for integrated guidance and control (IGC). A novel non-singular terminal dynamic surface control based IGC method is proposed. It can guarantee the missile with multiple disturbances fast hits the target with high accuracy, while considering the terminal impact angular constraint commendably. And the stability of the closed-loop system is strictly proved. The essence of integrated guidance and control design philosophy is reached that establishing a direct relation between guidance and attitude equations by “intermediate states” and then designing an IGC law for the obtained integrated cascade design model. Finally, a series of simulations and comparisons with a 6-DOF nonlinear missile that includes all aerodynamic effects are demonstrated to illustrate the effectiveness and advantage of the proposed IGC method.     

Sliding mode based fault detection,reconstruction and fault tolerant control scheme for motor systems

The fault-tolerant control problem belongs to the domain of complex control systems in which inter-control-disciplinary information and expertise are required. This paper proposes an improved faults detection, reconstruction and fault-tolerant control (FTC) scheme for motor systems (MS) with typical faults. For this purpose, a sliding mode controller (SMC) with an integral sliding surface is adopted. This controller can make the output of system to track the desired position reference signal in finite-time and obtain a better dynamic response and anti-disturbance performance. But this controller cannot deal directly with total system failures. However an appropriate combination of the adopted SMC and sliding mode observer (SMO), later it is designed to on-line detect and reconstruct the faults and also to give a sensorless control strategy which can achieve tolerance to a wide class of total additive failures. The closed-loop stability is proved, using the Lyapunov stability theory. Simulation results in healthy and faulty conditions confirm the reliability of the suggested framework.     

Tuning Proportional-Integral controllers to approximate simplified predictive control performance

An exact equivalence between PI (Proportional-Integral) and two-parameter SPC (Simplified Predictive Control) is developed to provide identical control of first order linear plants. A relationship between the PI control parameters and the SPC control parameters is described. This relationship that allows the same control in the case of first order linear plants is also found to provide tuning formulas that yield PI control which approximates SPC performance in the case of second order linear plants with widely separated Eigenvalues. Finally, an extension of the PI control algorithm to include future errors provides another exact PI–SPC equivalence for networked control of first order plants.     

APPLICATION OF IMPROVED PRODUCTION ACTIVITY CONTROL ARCHITECTURE FOR SHOP FLOOR INFORMATION SYSTEM IN DIGITAL MANUFACTURING

Shop floor control (SFC) is responsible for the coordination and control of the manufacturing physical and information flow within the shop floor in the manufacturing system. Weaknesses of the production activity control (PAC) architecture of the shop floor are addressed by the Maglica's new system architecture. This architecture gives rise to unlimited number of movers and producers thus evolving more complex but decentralized architecture. Beijing Institute of Technology - production activity control (BIT-PAC) architecture introduces an idea of sub-producers and sub-movers thus reducing the complexity of the architecture. All the equipments including sub-producers and sub-movers are considered to be passive in the proposed shop floor information system. The dissemination of information from sub-producers and sub-movers is done manually through a PC. Proposed BIT-PAC SFC architecture facilitates the information flow from shop floor to the other area of the organization. Effective use of internet information services (IIS) and SQL2000 is done along with the ASP.NET technology to implement the application logic. Applicability of the software based on BIT-PAC architecture is checked by running application software on a network PC that supports the dynamic flow of information from sub-producers and sub-movers to the other parts of the organization. Use of software is also shown at the end for BIT training workshop thus supporting the use of SFC architecture for similar kind of environments.     

基于滑模观测器的永磁同步电机模型预测电流控制研究

针对永磁同步电机无位置传感器高动态性能控制问题,对传统矢量控制存在电流内环PI控制器对系统性能的影响以及传统滑模观测器中动态转子位置角估计不准、稳态转速估计不精确等观测器性能进行了改进,提出了一种基于改进滑模观测器的永磁同步电机模型预测电流控制方法。根据永磁同步电机在同步旋转坐标系下的数学模型,选择了电机d、q电流作为状态变量,利用前向欧拉法推导出永磁同步电机d、q轴电流的预测模型。通过实时评估价值函数选出使得下一时刻电流跟踪效果最好的电压矢量,将其对应的开关状态作用于逆变器。同时,推导表贴式永磁同步电机的滑模观测器模型并对其观测出的转子位置角和转速进行补偿,得到较为精确的估算值。最后将算法在Matlab/Simulink进行了仿真试验。研究结果表明:所提出的控制方法动态性能好、稳态精度高。     

双馈风力发电机交流励磁及其幅度频率控制

叙述了双馈发电机变速恒频原理及电网侧和转子侧变频器矢量控制策略.与传统的同步发电机直流励磁不同,提出了一种无需转子位置编码器信号的幅度频率控制策略,仿真验证了幅度频率控制策略的有效性.     

Model predictive controller-based multi-model control system for longitudinal stability of distributed drive electric vehicle

Distributed drive electric vehicle(DDEV) has been widely researched recently, its longitudinal stability is a very important research topic. Conventional wheel slip ratio control strategies are usually designed for one special operating mode and the optimal performance cannot be obtained as DDEV works under various operating modes. In this paper, a novel model predictive controller-based multi-model control system (MPC-MMCS) is proposed to solve the longitudinal stability problem of DDEV. Firstly, the operation state of DDEV is summarized as three kinds of typical operating modes. A submodel set is established to accurately represent the state value of the corresponding operating mode. Secondly, the matching degree between the state of actual DDEV and each submodel is analyzed. The matching degree is expressed as the weight coefficient and calculated by a modified recursive Bayes theorem. Thirdly, a nonlinear MPC is designed to achieve the optimal wheel slip ratio for each submodel. The optimal design of MPC is realized by parallel chaos optimization algorithm(PCOA)with computational accuracy and efficiency. Finally, the control output of MPC-MMCS is computed by the weighted output of each MPC to achieve smooth switching between operating modes. The proposed MPC-MMCS is evaluated on eight degrees of freedom(8DOF)DDEV model simulation platform and simulation results of different condition show the benefits of the proposed control system.     

Robust internal model control of servo motor based on sliding mode control approach

This paper proposes a robust internal model control (IMC) based on sliding mode control (SMC) approach for high-performance motion control of a servo motor subject to uncertainties and/or disturbances. The proposed control strategy considers not only the simplicity and intuition of the IMC-based controller for a prescribed tracking performance but also the effectiveness of the SMC scheme to guarantee the robustness of the servo system. Since the performance of the IMC-based controller can be analyzed via a SMC structure, a robust control law based on the SMC technique is introduced into the IMC scheme to decrease the sensitivity to uncertainties and enhance the resistance to disturbances. Moreover, the 2-degree-of-freedom IMC integrating the robust SMC scheme is developed to further improve the control performance. The stability is analyzed based on Lyapunov theory, and the theoretical results show that a prescribed transient tracking performance and a final tracking accuracy of the servo system can be guaranteed. Comparative simulations and experiments are investigated to verify the high performance nature of the proposed control strategy.     

SRM的直接瞬时转矩控制及其改进型的仿真研究

针对开关磁阻电动机的转矩脉动较大的问题,对直接瞬时转矩控制方法进行了研究,并将其与PWM控制方法相结合,进一步介绍了一种改进型的控制方法。对两种控制方法的工作原理展开分析,重点介绍了转矩差值控制环节,它是依据转子角度位置的不同,将电动机的相绕组电感分为三个区间,并通过编程实现各个区间内电动机的控制。通过Matlab/Simulink软件分别搭建了四相8/6极开关磁阻电动机的直接瞬时转矩控制和改进型直接瞬时转矩控制的仿真模型,其中,瞬时反馈转矩是由相电流、转子位置和转矩三者之间的关系表查表得到。研究结果表明,两种方法都能够对转矩脉动起到抑制作用,但相比较而言,改进型直接瞬时转矩控制方法的抑制效果更加明显。     

A geometrical approach to computer-aided process planning for computer-controlled machine tools

This paper documents part of a research program which has been under way at the CIM Centre at Swinburne University of Technology since 1989. The purpose of the research program was to develop an open-architecture machine tool control system and then to see how that system could be used to change the distribution of traditional manufacturing design, planning and control functions. This paper examines one part of that research program and focuses on a methodology which could prove to be useful in the machine tool selection, cutter selection and cutter path generation phases of process planning for cutting operations on workpieces in computer-controlled machine tools.It is suggested that a configuration space transform be used for each cutter/machine tool combination to find the volume that the combination could remove from the uncut workpiece without removing any of the material that will form the final workpiece. A method of comparing these volumes from different combinations is then outlined. The output of this method is a reasonable sequence of machine tools and cutters. Path planning can then be carried out for each of the chosen combinations using a method similar to the one used to find the possible volume to be removed.Possible implementation techniques, and their limitations on existing computer hardware, are discussed and the most promising of these are identified, based upon some properties of configuration space transforms.