共查询到20条相似文献,搜索用时 15 毫秒
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针对机械手臂的非线性特点,提出了基于隶属度函数的多模型预测控制方法。该方法首先根据机械手臂的特点,选择合适的调度变量,将机械手臂的工作空间划分为若干个工作子空间,在每个子空间内的平衡点处对机械手臂进行线性化处理,得到相应的线性子模型,从而得到机械手臂的多模型表示;其次针对每个线性子模型设计局部预测控制器,使其在相应的子空间内达到控制要求;最后选择梯形隶属度函数与局部预测控制器进行加权求和,获得全局多模型预测控制器,以对机械手臂进行控制。仿真结果表明,当机械手臂的工作条件在大范围内变化时,全局多模型预测控制器的控制性能远优于常规PD控制器,达到了预期的控制目的。 相似文献
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将基于DNA双链结构的膜计算优化方法(dsDNA-MC)用于输入受限的非线性预测控制器设计,提出了基于dsDNA-MC优化的非线性系统预测控制算法。在对单输入单输出非线性系统预测控制分析的基础上,将非线性系统预测控制问题归结为具有输入约束的非线性系统优化问题,并采用dsDNA-MC算法来求解这一问题。仿真结果表明该算法可行、有效。 相似文献
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本文提出了一种针对Hammerstein模型的预测控制策略。该策略将Hammerstein模型中的无记忆非线性静态增益环节,改进成易于由中间变量求取控制量的环节,避免了求解高阶方程根的困难,又对线性环节采用线性系统的广义预测控制。由于引入了广义预测控制中多步预测的思想,抗噪声的能力显著提高。仿真结果验证了该策略的有效性。 相似文献
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本文提出了一种针对 Hammerstein模型的预测控制策略.该策略将Hammerstein模型中的无记忆非线性静态增益环节,改进成易于由中间变量求取控制量的环节,避免了求解高阶方程根的困难,又对线性环节采用线性系统的广义预测控制.由于引入了广义预测控制中多步预测的思想,抗噪声的能力显著提高.仿真结果验证了该策略的有效性. 相似文献
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用多模型的广义预测控制器对复杂的非线性液位系统进行仿真控制。通过在覆盖工况的若干个平衡点采用最小二乘法离线辨识建立多个线性模型,形成非线性系统的多模型表示,然后对各个子模型分别设计子控制器,采用基于相对残差的方法来实现控制增量的加权以获取控制增量。通过对单容液位系统的仿真,表明该方法的有效性。 相似文献
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王慧东 《自动化技术与应用》2009,28(12):131-134
本设计针对工业现场使用的双关节机器人,主要完成了硬件系统平台构建和软件系统的设计。应用单片机技术,设计一款主从操作的控制器,能够根据旋转编码器的控制指令精确的控制电机的速度、位置、正反转等物理量,从而满足机器人操作臂精确位置伺服驱动的要求。 相似文献
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In model predictive control (MPC), the input sequence is computed, minimizing a usually quadratic cost function based on the predicted evolution of the system output. In the case of nonlinear MPC (NMPC), the use of nonlinear prediction models frequently leads to non‐convex optimization problems with several minimums. This paper proposes a new NMPC strategy based on second order Volterra series models where the original performance index is approximated by quadratic functions, which represent a lower bound of the original performance index. Convexity of the approximating quadratic cost functions can be achieved easily by a suitable choice of the weighting of the control increments in the performance index. The approximating cost functions can be globally minimized by convex optimization techniques in order to compute the input sequence. The minimization of the performance index is carried out by an iterative optimization procedure, which guarantees convergence to the solution. Furthermore, for a nominal prediction model, asymptotic stability for the proposed NMPC strategy can be shown. In the case of considering an estimation error in the prediction model, input‐to‐state practical stability is assured. The control performance of the NMPC strategy is illustrated by experimental results. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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A design of adaptive model predictive control (MPC) based on adaptive control Lyapunov function (aCLF) is proposed in this article for nonlinear continuous systems with part of its dynamics being unknown at the starting time. Specifically, to guarantee the convergence of the closed-loop system with online predictive model updating, a stability constraint is designed. It limits the aCLF of the system under the MPC to be less than that under an online updated auxiliary adaptive control. The auxiliary adaptive control which implements in a sampling-hold fashion can guarantee the convergence of the controlled system. The sufficient conditions that guarantee the states to be steered to a small region near the equilibrium by the proposed MPC are provided. The calculation of the proposed algorithm does not depend on the model mismatch at the starting time. And it does not require the Lyapunov function of the state of the real system always to be reduced at each time. These provide the potential to improve the performance of the closed-loop system. The effectiveness of the proposed method is illustrated through a chemical process example. 相似文献
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This paper presents a Nonlinear Model Predictive Control (NMPC) algorithm utilizing a deterministic global optimization method. Utilizing local techniques on nonlinear nonconvex problems leaves one susceptible to suboptimal solutions at each iteration. In complex problems, local solver reliability is difficult to predict and dependent upon the choice of initial guess. This paper demonstrates the application of a deterministic global solution technique to an example NMPC problem. A terminal state constraint is used in the example case study. In some cases the local solution method becomes infeasible, while the global solution correctly finds the feasible global solution. Increased computational burden is the most significant limitation for global optimization based online control techniques. This paper provides methods for improving the global optimization rates of convergence. This paper also shows that globally optimal NMPC methods can provide benefits over local techniques and can successfully be used for online control. 相似文献
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任林 《计算机测量与控制》2012,20(1):81-84
针对单容液位系统紊流时的非线性特征,研究了基于RBF-ARX模型预测控制策略控制单容液位系统;讨论RBF-ARX模型结构的选取,模型参数辨识,RBF参数优化,基于RBF-ARX模型的预测控制策略等问题;模型的仿真结果,证实了RBF-ARX模型在非线性系统建模和辨识中的有效性;同基于全局线性ARX模型的预测控制器和PID控制器相比较,基于此模型的预测控制取得了优异的控制效果。 相似文献
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历经20多年的发展, 迭代学习模型预测控制在理论和应用方面都取得了长足的进步. 但由于批次工业过程复杂多样、结构各异、精细化程度较高, 现有的迭代学习模型预测控制理论仍面临着巨大挑战. 本文简要回顾了迭代学习模型预测控制理论的产生及发展, 阐述了二维预测模型、控制律迭代优化及二维稳定性等基本理论问题; 分析了现有方法在理论及应用方面的局限性, 说明了迭代学习模型预测控制在迭代建模、高效优化、变工况适应等方面面临的难点问题, 提出了可行的解决方案. 简要综述了近年来迭代学习模型预测控制理论和应用层面的发展动态, 指出了研究复杂非线性系统、快速系统、变工况系统对进一步完善其理论体系和拓宽其应用前景的意义, 展望了成品质量控制和动态经济控制等重要的未来研究方向. 相似文献
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针对步行双足机器人实时步态规划问题,提出了一种改进的非线性模型预测控制(NMPC)方法.采用扩展的关节坐标,将单腿支撑相(SSP)和双腿支撑相(DSP)统一表示为一个非线性动力学模型.通过对SSP和DSP的3个阶段设定运动学和动力学虚拟约束,将复杂实时步态规划问题转化为4个以预测时域内控制量二次型为代价函数的NMPC问题.采用直接法将连续优化问题参数化为有限维优化问题,并采用惩罚函数法将状态变量约束转化为代价函数中的惩罚项,从而得到能够用渐进二次规划(SQP)求解的有限维静态优化问题.仿真结果表明,应用该方法对BIP机器人模型进行实时步态规划,实现了包含足部转动的动态步行,且机器人满足稳定性条件,不发生侧滑,从而证明了该方法的有效性和可实现性. 相似文献
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地铁站台空调系统回路众多且具有强耦合和非线性特性,PID控制方法参数整定困难,无法兼顾乘客舒适性和能效最优,由于系统建模困难,非线性优化算法计算量大,智能控制方法难以实现工程应用.对此,提出一种地铁站台空调系统预测控制策略.首先,根据热湿负荷平衡和能量守恒定律建立地铁站台热动态特性预测模型;然后,将满足乘客舒适性并节省能耗作为系统优化目标,使用神经网络作为优化反馈控制器,将系统优化目标函数作为控制器优化性能指标,结合变分法和随机梯度下降法,对神经网络控制器的权值和阈值进行在线滚动优化,算法计算量小,占用存储空间适中.仿真实验结果表明,所提出的预测控制策略与传统PID控制方法相比,在满足乘客舒适性要求的前提下,系统响应时间可缩短约39.6%,末端风机能耗降低约73.39%. 相似文献
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A Nonlinear Robust Control Using a Fuzzy Reasoning and Its Application to a Robot Manipulator 总被引:1,自引:0,他引:1
Keigo Watanabe Kiyotaka Izumi Takaaki Otsubo 《Journal of Intelligent and Robotic Systems》1997,20(2-4):275-294
A simplified adaptive nonlinear robust controller (SANROC) has beenstudied in the literature. However, this is based on using the so-calledmatching condition. The present controller is not based on using such acondition. The estimate of an upper bound for uncertainties is usuallyincreased by using the adaptive mechanism, e.g., by consisting of amonotonically increased function. In this paper, instead of using such ananalytically adaptive mechanism, a fuzzy reasoning technique is alsoincorporated with the adaptive mechanism of SANROC. The proposed method isapplied to a pantagraph type robot manipulator. The effectiveness of thepresent method is illustrated by some experiments. 相似文献
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This article studies a data-driven predictive control for a class of control-affine systems which is subject to uncertainty. With the accessibility to finite sample measurements of the uncertain variables, we aim to find controls which are feasible and provide superior performance guarantees with high probability. This results into the formulation of a stochastic optimization problem (P), which is intractable due to the unknown distribution of the uncertainty variables. By developing a distributionally robust optimization framework, we present an equivalent and yet tractable reformulation of (P). Further, we propose an efficient algorithm that provides online suboptimal data-driven solutions and guarantees performance with high probability. To illustrate the effectiveness of the proposed approach, we consider a highway speed-limit control problem. We then develop a set of data-driven speed controls that allow us to prevent traffic congestion with high probability. Finally, we employ the resulting control method on a traffic simulator to illustrate the effectiveness of this approach numerically. 相似文献