冷带轧机厚控系统自适应鲁棒输出反馈动态控制器设计

冷带轧机厚控系统可被认为是一个受外界干扰的线性不确定时滞系统.本文首先设计了标称系统下的鲁棒输出反馈动态控制器,以改善闭环系统的动静态性能;其次,在系统不需要满足不确定性匹配条件的情况下,将参数和外部扰动不确定性综合考虑.应用Lyapunov稳定性理论设计了系统不确定性上界参数的自适应估计器和系统的自适应控制器,保证了闭环系统的渐近稳定性,减小了设计的保守性;两者结合实现了板带出口厚度的有效控制.最后通过一个仿真实例说明本文所提出的自适应鲁棒控制器的有效性.     

Optimal realizations of fixed-point implemented digital controllers with the smallest dynamic range

A novel approach is proposed to design optimal finite word length (FWL) realizations of digital controllers implemented in fixed-point arithmetic. A minimax-based search procedure is first formulated to obtain an optimal controller realization that optimizes an FWL closed-loop stability measure. Since this FWL closed-loop stability measure is solely linked to the fractional part or precision of fixed-point format, the resulting realization may not have the smallest dynamic range. A measure is then derived to indicate the dynamic range of fixed-point implemented realization. By choosing an appropriate orthogonal transformation of this dynamic range measure of the optimal precision controller realization, a numerical optimization method is developed to make the controller realization having the smallest dynamic range without sacrificing FWL closed-loop stability robustness. The proposed approach is more efficient than a direct optimization of some combined FWL closed-loop stability and dynamic range measure via a numerical means. The proposed approach is established within a unified framework that includes both the shift and delta operator parameterizations, which makes it possible to compare the closed-loop stability characteristics of the optimal FWL controller realizations using shift and delta operators, respectively. Through analysing the simulation results of a design example, some useful insights and understandings are obtained regarding the FWL controller realizations based on shift and delta operators.     

高空作业平台广义预测自适应控制及联合仿真*

为减少工程车辆控制系统开发周期和成本,以某型54m高空作业平台电液比例调平系统为研究对象,利用ADAMS软件建立作业机构多体动力学模型;采用AMESim软件建立电液比例调平系统模型;通过MATLAB/Simulink设计,采用改进的广义预测自适应控制的闭环控制器;以AMESim作为主仿真环境,通过软件接口将多体动力学模型和控制系统模型集成到AMESim中进行联合仿真。仿真结果表明,闭环控制器较常规PID控制器具有良好的动态特性,对模型失配和负载扰动表现出更强的适应性和鲁棒性,同时也证明了联合仿真的有效性。     

电视导引头伺服稳定平台数字控制器的研制

针对电视导引头系统对快速性要求高的特性,设计了一种基于DSP的高速数字控制器.以CCD摄像机作为位置环反馈传感器,以液浮式速率陀螺作为速度环反馈传感器,采用随动平台速率陀螺稳定方案的伺服稳定跟踪平台结构,给出了伺服控制器的软硬件设计,分析了针对该系统的双环PID控制算法的设计及调试方法.实验结果表明,该控制器动静态性能良好,可满足系统的要求.     

轧辊偏心的H∞输出反馈鲁棒重复控制

针对轧辊偏心问题,用线性矩阵不等式(LMI)方法设计了用于轧辊偏心补偿控制的H∞输出反馈鲁棒重复控制器,首先引入动态输出反馈来保证闭环系统的鲁棒稳定性,把重复控制器设计问题转化为H∞动态反馈控制器的设计问题,采用变量替换法将非线性矩阵不等式转化为线性矩阵不等式并对其求解进而得到控制器参数.另外在采用上述控制器保证系统鲁棒稳定性的同时,通过在重复控制器中引入一个前向系数进一步改善和提高系统的动态性能与稳态控制精度.理论证明与仿真研究表明当系统对象参数存在摄动时,这种控制器仍能有效地补偿轧辊偏心对产品质量的影响.     

Design of stable proportional-integral-plus controllers

There are a number of reasons why, in practical situations, implementation of an unstable dynamic controller may be undesirable. In particular, sensor failure can result in a forward path which is unstable and might severely damage the plant. As with many dynamic controller design techniques, the PIP design philosophy may produce controllers which stabilize the closed-loop system, but are themselves unstable. This paper builds upon the existing PIP design philosophy, introducing a design step which stabilizes the PIP controller. This design strategy not only stabilizes the controller, but also ensures that the equivalent closed-loop transfer function of the system remains identical (in the absence of model mismatch) to that of the original PIP closed-loop system.     

基于Matlab/xPC的直流电机参数辨识及双闭环控制研究

针对直流电机精确数学模型的获取及其双闭环控制器参数的整定问题,在Matlab/xPC目标环境使用递推最小二乘法对某型直流电机进行参数的在线辨识,获得某工作转速下的动态结构图参数.针对该结构图,在Simulink环境下对速度调节器和电流调节器的PI参数进行整定并仿真,达到满意效果后,将控制器下载到xPC目标机中,采用毫秒...     

Nonlinear dynamic modeling and control of a small-scale helicopter

A test bench for experimental testing of the attitude control of a small-scale helicopter is constructed. A nonlinear model with 10 states is developed for this experimental setup. The unknown model parameters are estimated using the extended Kalman filter with flight test data of the helicopter operating on the test bench. In this work, it is proved that the nonlinear helicopter dynamic model may be globally feedback linearized using the dynamic feedback linearization technique. In order to satisfy multiple closed-loop performance specifications simultaneously, a controller is proposed by applying the Convex Integrated Design (CID) method to the feedback linearized model. Finally, the controller is tested in simulation demonstrating the closed-loop performance of the proposed controller.     

Data-Driven Global Robust Optimal Output Regulation of Uncertain Partially Linear Systems

In this paper, a data-driven control approach is developed by reinforcement learning (RL) to solve the global robust optimal output regulation problem (GROORP) of partially linear systems with both static uncertainties and nonlinear dynamic uncertainties. By developing a proper feedforward controller, the GROORP is converted into a global robust optimal stabilization problem. A robust optimal feedback controller is designed which is able to stabilize the system in the presence of dynamic uncertainties. The closed-loop system is ensured to be input-to-output stable regarding the static uncertainty as the external input. This robust optimal controller is numerically approximated via RL. Nonlinear small-gain theory is applied to show the input-to-output stability for the closed-loop system and thus solves the original GROORP. Simulation results validates the efficacy of the proposed methodology.      

多变量极点配置自适应动态解耦控制器

本文提出了一种以多变量极点配置为基础的自适应解耦控制器,该控制器不仅可以任意配置闭环系统的极点位置而且可以直接对闭环系统实现动静态解耦控制,仿真实验结果表明该控制器比一般的极点配置控制器具有更好的控制性能。     

柔性臂协调运动系统的动态反馈镇定

研究柔性臂协调运动系统分布参数模型的镇定问题.基于系统能量关系和正实引理,提出一种构造性的设计方法.所设计的控制器由前馈和动态反馈两部分构成,其中动态反馈部分的传递函数是严格正实的.通过线性算子半群理论和LaSalle不变集原理,证明了闭环系统是渐近稳定的.     

直流调速系统中常规PI 与模糊PI 控制器的比较

转速电流双闭环直流调速系统中的PI控制器直接影响其调速性能,利用MATLAB分别建立了由常规PI与模糊PI控制器组成的转速电流双闭环控制直流调速系统的仿真模型,并进行了仿真。仿真结果表明,模糊PI控制器与常规PI控制器相比具有更好的动态稳定性和跟踪性能,对外界干扰具有较强的鲁棒性。     

非同轴两轮机器人自平衡与转向闭环控制

针对车速、车身侧倾角和前轮转角变化较大工况下的非同轴两轮机器人在基于前轮转角的自平衡控制中,因动力学模型准确性对自平衡控制带来的影响,设计了基于RBF神经网络模糊滑模控制的自平衡控制器,利用RBF神经网络的逼近特性,对动力学模型中非线性时变的不确定部分进行自适应逼近,从而提高动力学模型的准确性,并借助模糊规则削弱滑模控制中产生的系统抖振;以及因前轮转角用于自平衡控制中难以实现转向闭环控制,建立了基于纯跟踪法的轨迹跟踪控制器,并设计利用车身平衡时车身侧倾角与前轮转角的耦合关系,将转向闭环控制中的目标前轮转角替换为目标车身侧倾角,从而将自平衡控制器与轨迹跟踪控制器相结合,在保证车身平衡行驶的前提下,实现带有轨迹跟踪的转向闭环控制。实验结果表明,凭借动力学模型的较高准确性,RBF神经网络模糊滑模自平衡控制器具有鲁棒性好、超调量低和响应迅速的优点,并且利用车身平衡后车身侧倾角与前轮转角耦合关系,实现转向闭环控制是可行的,具有良好的轨迹跟踪效果。     

连续搅拌反应釜过程的闭环增益成形PID控制器设计

针对连续搅拌反应釜（CSTR）系统控制问题,设计了一种基于闭环增益成形算法的PID控制器,以提高PID控制器设计的简洁性和鲁棒性。首先假设期望闭环回路传递函数有一阶形式,同时将受控对象的一阶传递函数和PID控制器构成实际闭环回路传递函数。然后,比较期望闭环回路传递函数和实际闭环回路传递函数,即可确定PID参数。最后,以某CSTR系统为例,利用该方法设计了PID控制器,并通过仿真结果比较,检验了该方法所得PID控制器的良好鲁棒稳定性和动态品质。     

Precise control of the pressure-driven flows considering the pressure fluctuations induced by the process of droplet formation

The pressure-driven device is designed to control the flow rates of the droplet microfluidic systems, which can significantly reduce the flow-rate fluctuations coming from the pump source. As monodisperse droplets are formed in the microchannel, periodic pressure fluctuations can be induced by the dynamic process of droplet formation, which can influence the stability and control precision of the pressure-driven flows. The effects of the pressure fluctuations induced by the droplet formation process on the dynamic characteristics of the open-loop and closed-loop control pressure-driven devices are comparatively studied. Particularly, a proportional–integral controller (PI controller) is integrated with the closed-loop control pressure-driven device and the effects of the PI controller parameters on the stability and control accuracy of the pressure-driven flows are tested experimentally. Particularly, by properly choosing the parameters of the PI controller, the magnitude of the periodic pressure fluctuations can be reduced drastically, which obviously increases the control precision of the pressure-driven flows.     

深海自持式智能浮标双闭环模糊PID定深控制

针对深海自持式智能浮标运动模型非线性、强耦合性的特点,提出了一种基于双闭环反馈回路的模糊比例-积分-微分（proportion-integral-derivative,PID）定深控制器.根据浮标的浮力调节机构,分析了浮标的运动过程,建立了非线性运动方程.针对外环深度反馈回路,设计了模糊控制器.基于内环速度反馈回路与模糊控制器,设计了联级模糊PID定深控制器.传统PID定深控制器超调量5.6%,最终在目标深度±30 m范围内震荡,而双闭环模糊PID定深控制器在相同的上升时间内,超调量2.0%,深度误差控制在1.0%以内.存在外界扰动的情况下,通过双闭环模糊PID定深控制器的调节,浮标仍可以稳定在目标深度内.仿真结果表明,所建立的双闭环模糊PID定深控制系统具有良好的控制效果和稳定性.     

不确定时滞系统无记忆鲁棒镇定控制

本文研究了一类状态和控制同时存在滞后的线性时变不确定时滞系统的鲁棒镇定控制问题，针对所有容许的时变未知且有界的不确定性，得到了确保闭环系统二次稳定的充分条件。文中进一步把不确定时滞系统的二次镇定控制器设计问题等价为线性时不变系统的状态反馈标准Ｈ∞控制问题，并由此得到鲁棒镇定控制器综合设计方法。     

基于模糊控制的双闭环直流可逆调速系统的设计

对于双闭环直流可逆调速系统,提出了一种将模糊控制与常规PI控制相结合应用在转速环调节器设计的方法。根据工程经验与专家知识所确定的模糊控制规则,进行模糊推理,实现转速环调节器参数的动态整定。应用Matlab软件构建了双闭环直流可逆调速系统的仿真模型,并对转速环分别采用模糊PI控制器和常规PI控制器的直流可逆调速系统分别进行仿真实验并对比结果。从仿真结果可以得出采用模糊控制可以对直流可逆调速系统的动态与静态特性、抗扰性能、恢复性能以及跟踪性能有比较明显的改善与提高。     

输出概率密度函数鲁棒弹性最优跟踪控制

研究了一类随机动态系统的鲁棒弹性最优跟踪控制问题。在采用B样条神经网络模型逼近随机动态系统的输出概率密度函数(PDF)的基础上,同时考虑系统模型和控制器增益不确定性,结合Lyapunov稳定性理论和线性矩阵不等式(LMI)技术,引入增广控制作用,设计基于广义状态反馈的鲁棒弹性最优跟踪控制器,目的是使系统的输出PDF跟踪给定PDF。通过求解LMI,所得控制器不仅能实现跟踪目的,而且能确保该随机动态系统全局稳定并满足一定的线性二次型性能指标上界。仿真结果表明该方法简单易行,且无需任何设计参数调整。     

Transmission shift controller design based on a dynamic model of transmission response

Model-based controller design gives an insight into dynamic system behavior, and eliminates excessive reliance on the trial and error adjustments of controller parameters. A closed-loop speed controller for the inertia phase of the gearshift in an automatic transmission is designed here, based on a reduced order linear model of the transmission response extracted from a complex nonlinear dynamic simulation. The controller performance is then verified using the nonlinear simulation. Modification of hardware design to improve system responsiveness is also discussed.