Energy Preserving Time Integration for Constrained Multibody Systems

This paper describes an energy preserving integration method for thedynamic analysis of nonlinear multibody systems in the presence ofnonlinear constraints. The aspects of finite rotation incrementation,discrete energy conservation and the most common constraint types areexamined in detail. The application is made to several rigid bodyexamples, including an intermittent contact problem.     

On the Modeling of Shells in Multibody Dynamics

Energy preserving/decaying schemes are presented for the simulation ofthe nonlinear multibody systems involving shell components. Theproposed schemes are designed to meet four specific requirements:unconditional nonlinear stability of the scheme, a rigorous treatmentof both geometric and material nonlinearities, exact satisfaction ofthe constraints, and the presence of high frequency numericaldissipation. The kinematic nonlinearities associated with arbitrarilylarge displacements and rotations of shells are treated in a rigorousmanner, and the material nonlinearities can be handled when theconstitutive laws stem from the existence of a strain energy densityfunction. The efficiency and robustness of the proposed approach isillustrated with specific numerical examples that also demonstrate theneed for integration schemes possessing high frequency numericaldissipation.     

基于切换系统理论的异步电机最优直接转矩控制

提出一种系统建模和控制策略来实现两电平异步电机最优直接转矩控制来改善传统直接转矩控制存在的磁链和转矩脉动较大的问题。首先,基于切换系统理论建立两电平异步电机传动系统模型,然后在切换模型基础上,建立一个约束条件的有限时间最优控制目标函数,并利用滚动优化策略求解目标函数来实现最优直接转矩控制。仿真结果表明,该方法能够有效减少磁链和转矩脉动,降低逆变器开关频率,具有良好的动、静态性能。     

分段线性函数应用于延时系统的最优控制

本文把分段线性函数引入到求解延时系统的最优控制中，推得延时线性系统二次型最优控制问题的分段控制解答及其状态轨线估计，算例结果表明，该算法比方块脉冲函数算法具有更高的计算精度。     

高空风电系统的优化控制研究进展与挑战

为了实现“碳达峰,碳中和”的战略目标,我国将持续推动可再生能源的高比例发展,构建以新能源为主的新型电力系统.作为可再生的清洁源,风能的开发和利用已成为研究的重要方向.研究表明远离地面的高空中风速更加强劲并且更均匀,风向也更稳定,因此,风力发电的进一步突破可以通过用风筝捕获高空风能来实现.为了确保高空风能系统安全、经济、高效地运行,对其控制系统设计的要求极高.本文阐述了国际上几种主流高空风电技术的发电原理、发展进程以及现状.通过对典型的Yo-Yo式结构进行动力学建模,分析了各类非线性控制技术的原理和特点,具体描述了非线性模型预测控制原理和轨迹跟踪控制的仿真结果.总结了未来高空风能控制技术面临的控制算法计算量大,控制系统可靠性研究缺乏以及智能化水平不高等关键问题.     

An Attempt at the Classification of Energy Decaying Schemes for Structural and Multibody Dynamics

This paper analyzes the formulation of energy preserving/decaying schemes for dynamics problems. We argue that any energy preserving/decaying scheme can always be seen as composed of an underlying temporal discretization, that is then slightly modified in order to prove a discrete energy bound within a time step. While the details of the modified scheme depend in a critical way on the governing equations, the underlying discretization can in principle be applied to a variety of models. We review some of the temporal underlying schemes recently proposed in the literature, presenting them with a common notation. We show their similarities and highlight their differences.     

基于留优遗传算法的倒立摆最优LQR控制

被控系统稳定性与LQR控制器权重矩阵Q和R的选择有关。针对选择适当的Q和R使系统在约束条件下达到稳定性最优的问题,提出了一种通过留优遗传算法实现二级倒立摆系统LQR控制器参数寻优的新方法。以被控系统的动能积分为性能指标来实现寻优,以能量为寻优性能指标,可使二级倒立摆系统各部分的稳定性以统一的量纲表示。可依据倒立摆系统的耦合性,从总体的角度考虑系统的稳定性。仿真的结果表明了该方法的有效性。     

Formation-Containment Control Using Dynamic Event-Triggering Mechanism for Multi-Agent Systems

The paper proposes a novel approach for formation-containment control based on a dynamic event-triggering mechanism for multi-agent systems. The leader-leader and follower-follower communications are reduced by utilizing the distributed dynamic event-triggered framework. We consider two separate sets of design parameters: one set comprising control and dynamic event-triggering parameters for the leaders and a second set similar to the first one with different values for the followers. The proposed algorithm includes two novel stages of co-design optimization to simultaneously compute the two sets of parameters. The design optimizations are convex and use the weighted sum approach to enable a structured trade-off between the formation-containment convergence rate and associated communications. Simulations based on non-holonomic mobile robot multi-agent systems quantify the effectiveness of the proposed approach.      

控制能量约束条件下时滞系统最优控制与仿真

文中对时滞系统在控制能量存在约束时的最优控制问题进行了探讨.由控制器Youla参数化得到控制系统的敏感度函数和控制敏感度函数用来表示一个包含跟踪误差和控制能量在内的积分平方性能指标,针对不同类型的时滞过程运用谱分解的方法最小化该性能指标,从而导出相应控制器的设计方法,可使系统在控制能量约束条件下具有最优的控制性能.仿真研究进一步说明了所给设计方法的有效性.     

Solving Fixed Final Time Fractional Optimal Control Problems Using the Parametric Optimization Method

In this paper, the parametric optimization method is used to find optimal control laws for fractional systems. The proposed approach is based on the use for the fractional variational iteration method to convert the original optimal control problem into a nonlinear optimization one. The control variable is parameterized by unknown parameters to be determined, then its expression is substituted into the system state‐space model. The resulting fractional ordinary differential equations are solved by the fractional variational iteration method, which provides an approximate analytical expression of the closed‐form solution of the state equations. This solution is a function of time and the unknown parameters of the control law. By substituting this solution into the performance index, the original fractional optimal control problem reduces to a nonlinear optimization problem where the unknown parameters, introduced in the parameterization procedure, are the optimization variables. To solve the nonlinear optimization problem and find the optimal values of the control parameters, the Alienor global optimization method is used to achieve the global optimal values of the control law parameters. The proposed approach is illustrated by two application examples taken from the literature.     

直接能量平衡法协调控制系统稳定性对策研究

为了解决直接能量平衡法协调控制系统动态和稳态下的稳定性问题,通过对某大型单元机组自动控制系统的优化工作,大幅度提高了该指标.完善了直接能量平衡法协调控制系统策略.     

ITAE最优控制系统设计

研究ＩＴＡＥ最优控制系统的设计问题。针对这类性能指标中含有绝对值的最优控制问题，先将镇定控制器参数化，再用Ｌ１理论将其转化为求解线性规划和代数方程。所得的控制器是有理的、线性的，易于工程实现。     

Linear Problems of Optimal Control of Multiple-Valued Trajectories

This paper deals with rapidity and rendezvous problems and with problems with multi-valued and vector quality criteria for objects whose behavior is described by linear differential inclusions that contain controls.     

基于DSP的直接转矩控制系统研究

针对矢量控制中计算控制复杂、特性易受电动机参数变化影响的问题,用浅显易懂的语言描述了复杂繁琐的直接转矩控制理论,分析了磁链调节器和转矩调节器的构成以及它们之间协调工作,决定逆变器开关的特点。介绍了美国TI公司的电机控制专用DSP芯片TMS320LF2407A,并对基于该芯片的直接转矩控制系统的软硬件实现进行了阐述,对实验结果进行了简单分析。实际结果表明,该控制方法对电机参数依赖性小、动态性能好、鲁棒性强,是切实可行的。     

人机系统最优预见补偿跟踪控制研究

1　引　言预见控制理论是最优跟踪控制问题的新的出发点 ,其有效性在机器人、数字机床等路径控制中得到证实[1 ] .本文将预见控制应用到人机控制系统 .人具有“先前看”的能力 ,尤其是训练有素的驾驶员具有积极利用未来目标信号提高跟踪品质的预见操纵行为 .以驾驶员 -飞机目标跟踪控制系统为例 ,在人的最优控制模型( OCM)基础上 ,通过目标信息的预见显示 ,建立人的最优预见控制模型 ( OPCM) .应用数字最优预见控制理论 [2 ] ,对信号发生器产生的目标信号进行预见跟踪控制 .2　驾驶员最优预见控制模型 ( OPCM)2 .1　数字最优预见控制最…     

Bi-Objective Optimal Control Modification Adaptive Control for Systems with Input Uncertainty

This paper presents a new model-reference adaptive control method based on a bi-objective optimal control formulation for systems with input uncertainty. A parallel predictor model is constructed to relate the predictor error to the estimation error of the control effectiveness matrix. In this work, we develop an optimal control modification adaptive control approach that seeks to minimize a bi-objective linear quadratic cost function of both the tracking error norm and the predictor error norm simultaneously. The resulting adaptive laws for the parametric uncertainty and control effectiveness uncertainty are dependent on both the tracking error and the predictor error, while the adaptive laws for the feedback gain and command feedforward gain are only dependent on the tracking error. The optimal control modification term provides robustness to the adaptive laws naturally from the optimal control framework. Simulations demonstrate the effectiveness of the proposed adaptive control approach.      

非线性系统自适应最优切换控制方法

针对具有未知动态和M个平衡点的连续时间非线性系统, 将线性自适应最优切换控制器和未建模动态补偿器相结合, 基于嵌入转换技术和近似动态规划思想, 提出一种自适应最优切换控制方法. 首先在非线性系统的M个平衡点建立M个线性化模型, 当模型参数已知时, 提出由线性最优切换控制器、切换准则、未建模动态补偿器以及非线性系统组成的控制系统结构; 当模型参数未知时, 在每个平衡点附近采集输入和状态数据, 利用黎卡提方程的迭代求解公式、最小二乘方法、极小值原理以及二次规划技术得到非线性系统的自适应最优切换控制器和最优切换序列; 最后进行仿真实验, 实验结果验证了所提方法的有效性、优越性和实际可应用性.     

LQ最优控制系统加权矩阵Q的一种数值算法

利用ＬＱ最优控制逆问题的参数化解,将求解对称、非负定加权矩阵Ｑ的问题变为一类Ｆ－范数优化问题,给出一种求解ＬＱ最优控制指标函数中的加权矩阵Ｑ的简便而系统的方法。算法的优点在于任意给定一组自变量,通过解这类优化问题就可求得满足闭环特征要求的加权矩阵Ｑ,而且具有良好的收敛性。