Green Energy Complementary Based on Intelligent Power Plant Cloud Control System
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摘要: 针对现代电力系统中设施庞杂、多源异构海量数据难以有效处理、“信息孤岛”长期存在以及整体优化调度管理能力不足等问题, 基于云控制系统理论, 以智能电厂为研究对象, 本文提出了智能电厂云控制系统(Intelligent power plant cloud control system, IPPCCS)解决方案. 基于智能电厂云控制系统, 针对绿色能源发电波动性强、抗扰能力差的问题, 利用机器学习算法对采集到的风电、光伏输出功率进行短时预测, 获知未来风、光机组功率输出情况. 在云端使用经济模型预测控制(Economic model predictive control, EMPC)算法, 通过实时滚动优化得到水轮机组的功率预测调度策略, 保证绿色能源互补发电的鲁棒性, 充分消纳风、光两种能源, 减少水轮机组启停和穿越振动区次数, 在为用户清洁、稳定供电的同时降低了机组寿命损耗. 最后, 一个区域云数据中心的供电算例表明了本文方法的有效性.Abstract: Based on the theory of cloud control system, an intelligent power plant cloud control system (IPPCCS) is designed to overcome problems of complex objects, multi-sources heterogenous data, “information island” and the poor ability of overall optimization scheduling in modern electric power enterprise. To solve problems of strong fluctuation and poor disturbance resistance of green power generation, a machine learning method is used to obtain the short-term prediction value of wind and solar power based on their history data. Then in the cloud, the economic model predictive control (EMPC) algorithm is applied to provide the power predictive scheduling strategy of water turbines by real-time rolling optimization, to ensure the robustness of green energy complementary power generation, consume wind and solar power fully and reduce the frequency of starting/stopping and crossing the vibration zones of the turbines, which both provides clear and stable energy support for the users and protects the devices. The simulations show the effectiveness of the proposed method in an example of regional cloud data center.
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近20年, 多智能体系统的协同控制因其在无人机编队[1]、传感器网络同步[2]、多机器人协作[3]等工程中的广泛应用, 越来越受到控制理论领域学者们的关注. 传统的协同控制算法依赖智能体间的连续信息传输, 即使信息变化很小或没有变化仍然会进行信息传输, 这会造成电能、通信带宽、网络链路的低效利用[4]. 由于事件触发通信机制可以有效地节约能源和通信带宽, 基于事件触发机制的协同控制成为多智能体系统协同控制领域的研究热点[5−6]. 文献[7]给出一些基于事件触发通信机制的多智能体系统协同控制的研究成果.
多智能体系统事件触发协同控制领域的研究成果大多要求系统模型是精确可知的, 然而实际多智能体系统不可避免地存在未知参数、模型不确定、外部噪声等不确定因素. 文献[8]对无向网络的一类不确定非线性多智能体系统的事件触发趋同问题进行了研究. 文献[9]研究无向网络拓扑下一类二阶非线性多智能体系统的自适应事件触发趋同控制问题. 针对未知二阶非线性多智能体系统, 文献[10]利用自适应事件触发控制方法研究完全分布式控制问题. 文献[11]对网络拓扑信息未知的一般线性多智能体系统的完全分布式事件触发趋同问题进行研究. 针对控制方向未知的高阶多智能体系统, 文献[12]利用虚拟控制律设计自适应事件触发跟踪控制器. 文献[13]研究具有时滞和输入饱和的异构多智能体系统, 并给出基于观测器的事件触发趋同算法. 文献[14]利用组合测量事件触发机制, 研究拓扑结构为无向图的未知非线性二阶时滞多智能体系统的自适应趋同控制. 虽然文献[8−10, 14]研究的系统模型与本文相似, 但都采用基于组合测量的事件触发机制, 这种事件触发机制需要连续不断地监测邻居智能体的状态信息用以判断下一次触发时刻, 即算法依赖智能体间连续信息传输. 文献[15−16]利用输出调节理论, 对异构线性多智能体系统的事件触发输出同步问题进行研究. 文献[17]利用分布式内模设计, 研究一类非线性多智能体系统的事件触发全局鲁棒输出调节问题.
上述文献的分布式控制器虽然采用了事件触发机制进行设计, 但是所给的事件触发趋同算法依然依赖智能体间的连续信息传输. 触发函数对邻居智能体状态信息连续监测问题引起了研究人员的注意. 文献[18]利用基于反步法的分布式自适应输出反馈控制策略研究不确定异构线性多智能体系统的事件触发输出同步问题. 针对由一类高阶不确定非线性系统构成的无领导型异构多智能体系统, 文献[19]给出基于事件触发机制的分布式自适应趋同算法. 文献[20]分别对同构和异构线性多智能体系统的事件触发平均跟踪算法进行研究. 针对异构领导−跟随者型多智能体系统, 文献[21]分别给出基于模型和基于数据的事件触发趋同算法. 文献[22]基于动态事件触发机制, 对一般线性多智能体系统的编队包含控制问题进行研究. 针对拓扑为有向网络的不确定下三角非线性多智能体系统, 文献[23]利用神经网络设计分布式自适应异步事件触发趋同算法. 基于输出调节理论, 文献[24]研究异构线性多智能体系统的自适应事件触发输出趋同控制, 文献[25]研究一类异构非线性多智能体系统的分布式事件触发输出趋同控制问题, 文献[26]研究严格反馈非线性多智能体系统的半全局周期事件触发输出调节问题.
受上述文献启发, 本文研究异构不确定二阶非线性多智能体系统的事件触发状态趋同问题, 主要贡献有如下$ 3 $点: 1)本文研究领导−跟随者型异构不确定多智能体系统的状态趋同问题, 不仅跟随智能体的动力学方程存在不确定参数, 领导智能体也存在不确定参数. 文献[10, 15−16, 24−26]中的领导智能体均为完全已知的, 并未考虑领导智能体存在不确定参数的情形. 2)本文基于邻居智能体的观测状态设计事件触发趋同算法, 由于对邻居智能体的状态进行观测, 避免了事件触发函数对邻居智能体的连续监测, 做到控制器与触发函数都不依赖智能体间的连续信息传输. 同样研究异构不确定二阶非线性多智能体系统事件触发控制的文献[9−10], 其事件触发函数需要对邻居智能体的状态进行连续监测. 3)本文不确定参数为矩阵形式而非向量形式, 不同于以往将矩阵转变为向量的处理方法, 本文直接利用矩阵迹的不等式对矩阵自适应参数估计的收敛性进行证明.
1. 问题描述
为方便表示, 本文使用如下向量与矩阵的符号: $ ||\cdot||_{\rm{F }}$和$ ||\cdot|| $分别表示向量或矩阵的Frobenius范数和2范数, $ \otimes$为矩阵的克罗内克积, $ \mathrm{diag}\{a_1,\;\cdots, a_N\} $表示对角元素为$ a_i $的对角矩阵, $ \mathrm{tr}\{A\} $表示方阵$ A $的迹, $ 1_N $表示每个元素都为$ 1 $的$ N $维常向量, I表示单位矩阵, $ \lambda_{1X} $和$ \lambda_{NX} $分别表示$ N $阶对称矩阵$ X $的最小和最大特征根, $ {\cal{A}}(t) $表示渐近收敛到$ \boldsymbol 0 $的函数集合.
本文研究领导−跟随者型异构不确定二阶非线性多智能体系统事件触发趋同控制问题. 第$ i $个跟随智能体的动力学方程为:
$$ \begin{equation} \left\{\begin{aligned} \dot{x}_i(t)& = y_i(t)\\ \dot{y}_i(t)& = \theta_i^{\mathrm{T}}\phi_i(x_i(t),\;y_i(t))+u_i(t) \end{aligned}\right. \end{equation} $$ (1) 式中, $ x_i,\;y_i,\;u_i\in {\bf{R}}^n $分别表示第$ i $个智能体的位置、速度和控制输入; $ \theta_i\in {\bf{R}}^{n_i\times n} $为不确定常矩阵; $ \phi_i: {\bf{R}}^n\times {\bf{R}}^n\rightarrow {\bf{R}}^{n_i} $为已知向量函数.
领导智能体标记为$ 0 $号智能体, 其动力学方程为含有未知输入的二阶积分器型系统:
$$ \begin{equation} \left\{\begin{aligned} \dot{x}_0(t)& = y_0(t)\\ \dot{y}_0(t)& = \theta_0^{\mathrm{T}} \phi(t) \end{aligned}\right. \end{equation} $$ (2) 式中, $ x_0,\;y_0\in {\bf{R}}^n $分别为领导智能体的位置和速度; $ \theta_0\in {\bf{R}}^{n_0\times n} $为不确定常矩阵; $ \phi(t):[0,\;\infty)\rightarrow {\bf{R}}^{n_0} $为已知向量函数.
本文的目标是设计基于事件触发机制的趋同控制算法, 使得$ \lim_{t\rightarrow\infty}x_i(t) = x_0(t),\;y_i(t) = y_0(t). $
领导−跟随者型多智能体系统(1)、(2)的网络拓扑用有向图$ {\cal{G}} = \{{\cal{V}},\;{\cal{E}}\} $描述, 其中$ {\cal{V}} = \{0,\;1,\; \cdots, N\} $为智能体集合, $ {\cal{E}} = {\cal{V}}\times{\cal{V}} $为边集. $ (i,\;j)\in{\cal{E}} $表示一条从智能体$ j $到智能体$ i $的有向边, 相应的邻接权重$ a_{ij}>0 $, 否则$ a_{ij} = 0 $. 有向边序列$ (i_l,\; i_{l-1}), l=1,\; \cdots,\; k\,\; $表示从智能体$ i_0 $到智能体$ i_k $的一条路径. 图$ {\cal{G}} $的拉普拉斯矩阵$ {\cal{L}} $定义为$ l_{ii} = \sum_{j \,\;=\,\; 0}^Na_{ij}, l_{ij} = -a_{ij},\;i\neq j $.
注1. 由于领导智能体不能接收到跟随智能体的信息, 有向图$ {\cal{G}} $的拉普拉斯矩阵$ {\cal{L}} $可表示为:
$$ \begin{equation*} {\cal{L}} = \left[\begin{array}{cc}0&{\bf 0}_{1\times N}\\ *&L \end{array}\right],\; \; L\in {\bf{R}}^{N\times N},\; \; *\in {\bf{R}}^{N} \end{equation*} $$ 由文献[27]的引理3可知, 当假设1成立时, 矩阵$ L $是非奇异的, 并且存在矩阵$ Q = \mathrm{diag}\{1/ q_1, \cdots,\;1/ q_N\} $, $ H = (QL+L^{\mathrm{T}}Q) /{2}$为正定矩阵, 其中$ [q_1,\;\cdots,\; q_N]^{\mathrm{T}} = L^{-1}1_N $.
为证明算法的稳定性, 需要以下假设和引理.
假设1. 对于任意跟随智能体$ i,\;i = 1,\;\cdots,\;N $, 至少存在一条由领导智能体到跟随智能体$ i $的有向路径.
假设2. $ \phi(t) $, $ \phi_i(x_i(t) $, $ y_i(t)) $为不恒等于$ \bf 0 $的有界向量函数.
假设3. 在不确定输入$ \theta_0^{\mathrm{T}}\phi(t) $的作用下, 领导智能体的状态有界.
引理1[28]. 考虑如下系统:
$$ \begin{equation} \dot{x}(t) = f(t,\;x(t),\;u(t)) \end{equation} $$ (3) 式中, $ f:[0,\;\infty)\times {\bf{R}}^n\times {\bf{R}}^m\rightarrow {\bf{R}}^n $对$ t $是分段连续的, 对$ x(t) $和$ u(t) $满足局部Lipschitz条件. 输入$ u(t) $对所有$ t\geq0 $是分段连续且有界的函数. 如果系统(3)是输入状态稳定的且$ u(t)\in{\cal{A}}(t) $, 则亦有状态$ x(t) \in {\cal{A}}(t) $.
2. 事件触发趋同算法的设计
由于领导智能体的参数$ \theta_0 $不确定, 首先为领导智能体设计如下参数观测器:
$$ \begin{equation} \left\{\begin{aligned} \dot{\hat{y}}_0& =( \hat{\theta}_0^0)^{\mathrm{T}}\phi(t)-s_0(\hat{y}_0-y_0)\\ \dot{\hat{\theta}}_0^0& = -\phi(t)(\hat{y}_0-y_0)^{\mathrm{T}} \end{aligned}\right. \end{equation} $$ (4) 式中, $\hat{y}_0 $为领导智能体速度状态的观测值, $s_0>0 $为正数, $ \hat{\theta}_0^0(t) $用以估计参数$ \theta_0 $. 跟随智能体的参数$ \theta_i $同样不确定, 设计如下参数观测器:
$$ \begin{equation} \left\{\begin{aligned} \dot{\hat{y}}_i& = \hat{\theta}_i^{\mathrm{T}}\phi_i(x_i,\;y_i)+u_i-s_i(\hat{y}_i-y_i)\\ \dot{\hat{\theta}}_i& = -\phi_i(x_i,\;y_i)(\hat{y}_i-y_i)^{\mathrm{T}} \end{aligned}\right. \end{equation} $$ (5) 式中, $\hat{y}_i $为第i个智能体速度状态的观测值, $ s_i>0 $为正数, $ \hat{\theta}_i(t) $用以估计参数$ \theta_i $.
由于领导智能体含有不确定控制输入$ \theta_0^{\mathrm{T}}\phi(t) $, 为了使跟随智能体跟踪上领导智能体, 为跟随智能体$ i $设计如下$ \theta_0 $参数的观测器:
$$ \begin{equation} \dot{\hat{\theta}}_0^i(t) = -\mu\sum\limits_{j = 0}^Na_{ij}(\hat{\theta}_0^i(t_k^i)-\hat{\theta}_0^j(t_{k'}^j)) \end{equation} $$ (6) 式中, $ \mu>0 $为常数, $ t_k^i $和$ t_{k'}^j $为智能体$ i $和$ j $的事件触发时刻, 并且有$ t_0^i = t_0^j = 0 $.
在触发时刻$ t_{k'}^j $, 智能体$ j $将其采样信息$ \hat{\theta}_0^j(t_{k'}^j) $, $ x_j(t_{k'}^j) $和$ y_j(t_{k'}^j) $发送给邻居智能体$ i $. 智能体$ i $利用采样信息$ \hat{\theta}_0^j(t_{k'}^j) $, $ x_j(t_{k'}^j) $和$ y_j(t_{k'}^j) $估计智能体$ j $在下一次采样时刻$ t_{(k+1)'}^j $前的位置和速度. 用$ \hat{x}_j^i(t) $和$ \hat{y}_j^i(t) $表示时间段$ [t_{k'}^j,\;t_{(k+1)'}^j) $内智能体$ i $对智能体$ j $的状态信息估计, 状态估计方程为:
$$ \begin{equation} \left\{\begin{aligned} \dot{\hat{x}}_j^i(t)& = \hat{y}_j^i(t)\\ \dot{\hat{y}}_j^i(t)& = (\hat{\theta}_0^{j}(t_{k'}^j))^{\mathrm{T}}\phi(t) \end{aligned}\right. \end{equation} $$ (7) 式中, 初始状态分别为$ \hat{x}_j^i(t_{k'}^j) = x_j(t_{k'}^j) $, $ \hat{y}_j^i(t_{k'}^j) = y_j(t_{k'}^j) $.
同时, 智能体$ j $也将利用其事件触发采样信息估计其自身的状态信息. 如果智能体$ i $和$ l $同时接收到智能体$ j $的事件触发采样信息, 则不难验证智能体$ i $, $l $和$ j $拥有相同状态估计值, 即:
$$ \hat{x}_j^i(t) = \hat{x}_j^l(t) = \hat{x}_j^j(t),\;\hat{y}_j^i(t) = \hat{y}_j^l(t) = \hat{y}_j^j(t) $$ 记$ \hat{\xi}_{ix} = \sum_{j = 0}^N a_{ij}(\hat{x}_i^i - \hat{x}_j^i),\; \hat{\xi}_{iy} = \sum_{j = 0}^N a_{ij}(\hat{y}_i^i - \hat{y}_j^i) $, 为跟随智能体式(1)设计如下事件触发趋同控制器:
$$ \begin{equation} u_i = -\hat{\theta}_i^{\mathrm{T}}\phi_i(x_i,\;y_i)+(\hat{\theta}_0^{i})^{\mathrm{T}}\phi(t)-ck_1\hat{\xi}_{ix}-ck_2\hat{\xi}_{iy} \end{equation} $$ (8) 式中, $ k_1 $, $ k_2>0 $为耦合增益; $ c>0 $为反馈增益. $ k_1 $, $ k_2 $和$ c $可根据下文式(22)选取. 智能体$ i $的第$ k+1 $次事件触发时刻由如下条件给出:
$$ \begin{equation} t_{k+1}^i = \min\{t>t_k^i|T_{i1}(t)\geq0\; \mathrm{or}\; T_{i2}(t)\geq0\} \end{equation} $$ (9) 式中, $T_{i1}(t) = ||\epsilon_i(t)||_{\rm{F}}^2 - f_{i1}(t),\; T_{i2}(t) = ||e_i(t)||^2 \;- f_{i2}(t)$, $ \epsilon_i(t) = \hat{\theta}_0^i(t_k^i)-\hat{\theta}_0^i(t) $, $ e_i(t) = k_1e_{ix}(t)+ k_2e_{iy}(t) $,$ e_{ix}(t) =\hat{x}_i^i(t)-x_i(t) $, $ e_{iy}(t) = \hat{y}_i^i(t)-y_i(t) $, 正函数$ f_{i1}(t),\;f_{i2}(t)\in{\cal{A}}(t) $.
领导智能体$ 0 $的第$ k+1 $次事件触发时刻由如下条件确定:
$$ \begin{equation} t_{k+1}^0 = \min\{t>t_k^0|T_{01}(t)\geq0\; \mathrm{or}\; T_{02}(t)\geq0\} \end{equation} $$ (10) 式中, 各符号定义与式(9)中符号定义类似.
注2. 跟随智能体的控制输入式(8)只依赖其自身状态、邻居智能体的估计状态和估计参数$ \hat{\theta} _0^i(t), \hat{\theta}_i(t) $, 仅需要邻居智能体提供离散的信息 $ \hat{\theta}_0^j(t_{k'}^j) $, $ x_j(t_{k'}^j) $和$ y_j(t_{k'}^j) $, 不依赖邻居智能体的任何连续信息传输. 同样, 事件触发条件(9)、(10)也不依赖邻居智能体的任何连续信息传输. 因此, 本文提出的事件触发趋同算法完全不依赖智能体间的连续信息传输.
3. 事件触发控制器的稳定性分析
命题1. 如果假设2成立, 参数观测器式(4)、式(5) 中的$ \hat{\theta}_0^0(t) $和$ \hat{\theta}_i(t) $可渐近收敛到$ \theta_0 $和$ \theta_i $, 即$ \lim_{t\rightarrow\infty}\hat{\theta}_0^0(t) = \theta_0 $, $ \lim_{t\rightarrow\infty}\hat{\theta}_i(t) = \theta_i. $
证明. 记$ \tilde{y}_i(t) = \hat{y}_i(t)-y_i(t) $, $ \tilde{\theta}_i(t) = \hat{\theta}_i(t)- \theta_i $. 对于观测器式(5), 可得:
$$ \begin{equation} \left\{\begin{aligned} \dot{\tilde{y}}_i(t)& = \tilde{\theta}_i^{\mathrm{T}}(t)\phi_i(x_i(t),\;y_i(t))-s_i\tilde{y}_i(t)\\ \dot{\tilde{\theta}}_i(t)& = -\phi_i(x_i(t),\;y_i(t))\tilde{y}_i^{\mathrm{T}}(t) \end{aligned}\right. \end{equation} $$ (11) 选取如下李雅普诺夫函数:
$$ V_{i1} = \frac{1}{2}\tilde{y}_i^{\mathrm{T}}(t)\tilde{y}_i(t)+\frac{1}{2}\mathrm{tr}\{\tilde{\theta}_i^{\mathrm{T}}(t) \tilde{\theta}_i(t)\} $$ 沿式(11)的轨迹求$ V_{i1} $的导数, 可得:
$$ \dot{V}_{i1} = -s_i\tilde{y}_i^{\mathrm{T}}(t)\tilde{y}_i(t) $$ 这表明$ \lim_{t\rightarrow\infty}\tilde{y}_i(t) = \bf 0 $. 由系统 (11)可知$ \tilde{y}_i(t) {\text{恒等于}}\, \bf 0 $, 可得$ \tilde{\theta}_i^{\mathrm{T}}(t)\phi_i(x_i (t),\;y_i(t))\,{\text{恒等于}}\, \bf 0$. 由假设2可知$ \phi_i (x_i(t),\;y_i(t)) $不恒等于$ \bf 0 $且有界, 从而可得$ \lim_{t\rightarrow\infty} \hat{\theta}_i(t) = \theta_i $. 亦可证明$ \lim_{t\rightarrow\infty} \hat{\theta}_0^0(t) = \theta_0 $.
□ 命题2. 如果假设1和假设2成立, 在事件触发条件(9)、(10) 作用下, 估计参数$ \hat{\theta}_0^i(t) $渐近收敛至$ \theta_0 $.
证明. 记$ \zeta_i(t) = \sum_{j = 0}^Na_{ij}(\tilde{\theta}_0^i(t)-\tilde{\theta}_0^j(t)) $, $ \sigma_i(t) = \sum_{j = 0}^Na_{ij}(\epsilon_i(t)-\epsilon_j(t)) $, $ \tilde{\theta}_0^i(t) = \hat{\theta}_0^i(t)-\theta_0 $. 由式(6)可得:
$$ \begin{equation} \dot{\tilde{\theta}}_0^i(t) = -\mu\zeta_i(t)-\mu\sigma_i(t) \end{equation} $$ (12) 选取如下李雅普诺夫函数:
$$ \begin{equation} V_2 = \sum\limits_{i = 1}^N\frac{1}{2q_i}\mathrm{tr}\{\zeta_i^{\mathrm{T}}(t)\zeta_i(t)\} \end{equation} $$ (13) 由式(12)可得$ V_2 $的导数:
$$ \begin{equation*} \begin{aligned} \dot{V}_2 = \;&-\mu\mathrm{tr}\{\zeta^{\mathrm{T}}((QL)\otimes I_{n_0})\zeta\}\;-\\ &\mu\mathrm{tr}\{\zeta^{\mathrm{T}}((QL)\otimes I_{n_0})\sigma\}\;+\\ &\sum_{i = 1}^N\frac{a_{i0}}{q_i}\mathrm{tr}\{\zeta_i^{\mathrm{T}}\phi(t)\tilde{y}_0^{\mathrm{T}}\} \end{aligned} \end{equation*} $$ 式中, $ \zeta = [\zeta_1^{\mathrm{T}},\;\cdots,\;\zeta_N^{\mathrm{T}}]^{\mathrm{T}} $, $ \sigma = [\sigma_1^{\mathrm{T}},\;\cdots,\;\sigma_N^{\mathrm{T}}]^{\mathrm{T}} $.
对于$ \dot{V}_2 $的第1项, 由附录的引理2可得:
$$ \begin{equation} \begin{split} \mathrm{tr}\{\zeta^{\mathrm{T}}((QL)\otimes I_{n_0})\zeta\} = \;&\mathrm{tr}\{\zeta^{\mathrm{T}}(H\otimes I_{n_0})\zeta\}\;\geq\\ & \lambda_{1H}\sum_{i = 1}^N\mathrm{tr}\{\zeta_i^{\mathrm{T}}\zeta_i\} \end{split} \end{equation} $$ (14) 记$ L_e $为$ L $的增广矩阵, 即$ L_e = [-a_0|L] $, $ a_0 \;= [a_{01},\;\cdots,\; a_{0N}]^{\mathrm{T}} $. 令$ \epsilon(t) = [\epsilon_0^{\mathrm{T}}(t),\;\epsilon_1^{\mathrm{T}}(t),\;\cdots,\; \epsilon_N^{\mathrm{T}}(t)]^{\mathrm{T}} $, $ \Xi = QLL^{\mathrm{T}}Q $, $ \Delta = L_e^{\mathrm{T}}L_e $. 易证$ \sigma(t) = (L_e\otimes I_{n0})\epsilon(t) $. 对于$ \dot{V}_2 $的后2项, 由附录A的引理2和引理3可得:
$$ \begin{split} &-\mathrm{tr}\{\zeta^{\mathrm{T}}((QL)\otimes I_{n_0})\sigma\}\leq\frac{\eta_1}{2}\mathrm{tr}\{\zeta^{\mathrm{T}}(\Xi\otimes I_{n_0})\zeta\}\; +\\ &\qquad\frac{1}{2\eta_1}\mathrm{tr}\{\epsilon^{\mathrm{T}}(\Delta\otimes I_{n_0})\epsilon\}\leq \frac{\eta_1\lambda_{N\Xi}}{2}\sum_{i = 1}^N\mathrm{tr}\{\zeta_i^{\mathrm{T}}\zeta_i\} \;+\\ &\qquad\frac{\lambda_{N\Delta}}{2\eta_1}\sum_{i = 0}^N\mathrm{tr}\{\epsilon_i^{\mathrm{T}}\epsilon_i\}\\[-1pt] \end{split} $$ (15) $$ \begin{equation} \begin{split} & \sum_{i = 1}^N\frac{a_{i0}}{q_i}\mathrm{tr}\{\zeta_i^{\mathrm{T}}\phi(t)\tilde{y}_0^{\mathrm{T}}\}\leq \frac{\eta_2}{2}\sum_{i = 1}^N\mathrm{tr}\{\zeta_i^{\mathrm{T}}\zeta_i\}\;+\\ &\;\;\;\sum_{i = 1}^N\frac{a_{i0}^2}{2\eta_2q_i^2}\mathrm{tr}\{\tilde{y}_0\phi^{\mathrm{T}}(t)\phi(t)\tilde{y}_0^{\mathrm{T}}\} \end{split} \end{equation} $$ (16) 式中, $ \eta_1\in(0,\;\lambda_{1H}/ \lambda_{N\Xi}) $, $ \eta_2\in(0,\;\mu\lambda_{1H}) $.
将式(14) ~ 式(16)代入$ \dot{V}_2 $, 有:
$$ \begin{equation*} \begin{aligned} \dot{V}_2\leq\;&-\left(\mu\left(\lambda_{1H}-\frac{\eta_1\lambda_{N\Xi}}{2}\right)-\frac{\eta_2}{2}\right) \sum_{i = 1}^N\mathrm{tr}\{\zeta_i^{\mathrm{T}}\zeta_i\}\;+\\ &\frac{\mu\lambda_{N\Delta}}{2\eta_1}\sum_{i = 0}^N\mathrm{tr}\{\epsilon_i^{\mathrm{T}}\epsilon_i\} +\sum_{i = 1}^N\frac{a_{i0}^2}{2\eta_2q_i^2}\mathrm{tr}\{\tilde{y}_0\phi^{\mathrm{T}}\phi\tilde{y}_0^{\mathrm{T}}\} \end{aligned} \end{equation*} $$ 令$ \kappa = \min\{q_i(\mu(2\lambda_{1H}-\eta_1\lambda_{N\Xi})-\eta_2)\} $. 由事件触发条件(9)、(10)和命题1易知存在一个函数$ b(t)\in{\cal{A}}(t) $, 使得:
$$ \frac{\mu\lambda_{N\Delta}}{2\eta_1}\sum\limits_{i = 0}^N\mathrm{tr}\{\epsilon_i^{\mathrm{T}}\epsilon_i\} +\sum\limits_{i = 1}^N\frac{a_{i0}^2}{2\eta_2q_i^2}\mathrm{tr}\{\tilde{y}_0\phi^{\mathrm{T}}\phi\tilde{y}_0^{\mathrm{T}}\}\leq b(t) $$ 即
$$ \begin{equation*} \dot{V}_2\leq -\kappa V_2+b(t) \end{equation*} $$ 由引理1可得$ V_2(t)\in{\cal{A}}(t) $, 即$ \lim_{t\rightarrow\infty}\zeta(t) = \bf 0 $. 记$ \tilde{\Theta}_0(t) = [(\tilde{\theta}_0^{1})^{\mathrm{T}},\;\cdots,\;(\tilde{\theta}_0^{N})^{\mathrm{T}}]^{\mathrm{T}} $, 易得:
$$ \zeta(t) = (L\otimes I_{n_0})\tilde{\Theta}_0(t)+a_0\otimes \tilde{\theta}_0^0(t) $$ 由命题1可知$ \lim_{t\rightarrow\infty}\tilde{\theta}_0^0(t) = \bf 0 $, 又因$L $为非奇异矩阵, 可得$ \lim_{t\rightarrow\infty}\tilde{\Theta}_0(t) = \bf 0 $, 即$ \hat{\theta}_0^i(t) $渐近收敛至$ \theta_0 $.
□ 注3. 由命题1和命题2可知, 观测器式(4)和式(5)可实现对参数$ \theta_0 $和$ \theta_i $的渐近估计, 分布式观测器式(6)在观测器式(4)基础上, 可渐近收敛到$ \theta_0 $. 只有观测器渐近收敛时, 所设计的事件触发趋同算法才可达到渐近趋同, 否则只能达到一致渐近有界趋同. 此外, 不确定参数$ \theta_0 $和$ \theta_i $均为矩阵而非向量, 命题1和命题2直接采用矩阵迹的不等式进行收敛性证明. 相比转化为扩维向量, 本文算法更简单明了.
定理1. 如果假设1 ~ 3成立, 则事件触发算法式(8)、式(9)可使领导−跟随者型多智能体系统达到状态趋同.
证明. 记$ \xi_{ix} = \sum_{j = 0}^Na_{ij}(x_i - x_j),\; \xi_{iy} = \sum_{j = 0}^N a_{ij} \times\;(y_i-y_j) $为第$ i $个跟随智能体的相对状态信息, 易证:
$$ \begin{equation} \left\{\begin{aligned} \dot{\xi}_{ix} = \;&\xi_{iy}\\ \dot{\xi}_{iy} = \;&\sum_{j = 1}^Na_{ij}(\tilde{\theta}_j^{\mathrm{T}}\phi_j-\tilde{\theta}_i^{\mathrm{T}}\phi_i) -a_{i0}\tilde{\theta}_i^{\mathrm{T}}\phi_i\;+\\ &\sum_{j = 1}^Na_{ij}((\tilde{\theta}_0^{i})^{\mathrm{T}}-(\tilde{\theta}_0^{j})^{\mathrm{T}})\phi(t)+a_{i0}(\tilde{\theta}_0^{i})^{\mathrm{T}}\phi(t)\;-\\ &ck_1\sum_{j = 1}^Na_{ij}(\hat{\xi}_{ix}-\hat{\xi}_{jx})-ck_1a_{i0}\hat{\xi}_{ix}\;-\\ &ck_2\sum_{j = 1}^Na_{ij}(\hat{\xi}_{iy}-\hat{\xi}_{jy})-ck_2a_{i0}\hat{\xi}_{iy} \end{aligned}\right. \end{equation} $$ (17) 记$ \xi_i = k_1\xi_{ix}+k_2\xi_{iy} $. 选取如下李雅普诺夫函数:
$$ \begin{equation} V_3 = \sum\limits_{i = 1}^N\frac{\rho_i}{2}\xi_{ix}^{\mathrm{T}}\xi_{ix}+\sum\limits_{i = 1}^N\frac{1}{2q_i}\xi_i^{\mathrm{T}}\xi_i \end{equation} $$ (18) 式中, $ \rho_i = k_1^2/q_i $.
沿式(17)的轨迹可得$ V_3 $的导数:
$$ \begin{equation*} \begin{aligned} \dot{V}_3 =\; &\sum_{i = 1}^N\left(-\frac{\rho_ik_1}{k_2}\xi_{ix}^{\mathrm{T}}\xi_{ix}+\frac{k_1}{q_ik_2}\xi_i^{\mathrm{T}}\xi_i\right)\;+\\ &k_2\xi^{\mathrm{T}}((QL)\otimes I_n)\tilde{\theta}_{\phi}+k_2\xi^{\mathrm{T}}((QL)\otimes I_n)\tilde{\theta}_{\phi}^{0}\;-\\ &ck_2\xi^{\mathrm{T}}((QL)\otimes I_n)\hat{\xi} \end{aligned} \end{equation*} $$ 式中, $ \xi = [\xi_1^{\mathrm{T}},\;\cdots,\;\xi_N^{\mathrm{T}}]^{\mathrm{T}} $, $ \hat{\xi} = [\hat{\xi}_1^{\mathrm{T}},\;\cdots,\;\hat{\xi}_N^{\mathrm{T}}]^{\mathrm{T}} $, $ \tilde{\theta}_{\phi} = [\phi_1^{\mathrm{T}}\tilde{\theta}_1,\;\cdots,\;\phi_N^{\mathrm{T}}\tilde{\theta}_N]^{\mathrm{T}} $, $ \tilde{\theta}_{\phi}^0 = [\phi^{\mathrm{T}}(t)\tilde{\theta}_0^{1},\;\cdots,\;\phi^{\mathrm{T}}(t)\tilde{\theta}_0^{N}]^{\mathrm{T}} $, $ \hat{\xi}_i = k_1\hat{\xi}_{ix}+k_2\hat{\xi}_{iy} $.
根据Young不等式, 存在$ \gamma_1,\;\gamma_2\in(0,\;1) $, 使得$ \dot{V}_3 $的第2项和第3项满足如下不等式:
$$ \begin{equation} \begin{split} & \xi^{\mathrm{T}}((QL)\otimes I_n)\tilde{\theta}_{\phi} = \frac{\gamma_1}{2}\xi^{\mathrm{T}}(\Xi\otimes I_n)\xi+\frac{1}{2\gamma_1} \tilde{\theta}_{\phi}^{\mathrm{T}}\tilde{\theta}_{\phi}\;\leq\\ &\;\;\;\frac{\gamma_1\lambda_{N\Xi}}{2}\sum_{i = 1}^N\xi_i^{\mathrm{T}}\xi_i+\frac{1}{2\gamma_1}\sum_{i = 1}^N \phi_i^{\mathrm{T}}\tilde{\theta}_i\tilde{\theta}_i^{\mathrm{T}}\phi_i\\[-1pt] \end{split} \end{equation} $$ (19) $$ \begin{equation} \begin{split} \xi^{\mathrm{T}}&((QL)\otimes I_n)\tilde{\theta}_{\phi}^0 = \frac{\gamma_2}{2}\xi^{\mathrm{T}}(\Xi\otimes I_n)\xi+\frac{1}{2\gamma_2} (\tilde{\theta}_{\phi}^{0})^{\mathrm{T}}\tilde{\theta}_{\phi}^0\;\leq\\ &\frac{\gamma_2\lambda_{N\Xi}}{2}\sum_{i = 1}^N\xi_i^{\mathrm{T}}\xi_i+\frac{1}{2\gamma_2}\sum_{i = 1}^N \phi^{\mathrm{T}}\tilde{\theta}_0^{i}(\tilde{\theta}_0^{i})^{\mathrm{T}}\phi \\[-1pt]\end{split} \end{equation} $$ (20) 对于$ \dot{V}_3 $的最后1项, 有如下不等式:
$$ \begin{equation} \begin{split} -\xi^{\mathrm{T}}&((QL)\otimes I_n)\hat{\xi} = -\xi^{\mathrm{T}}((QL)\otimes I_n)\xi\;-\\ &\xi^{\mathrm{T}}((QL^2)\otimes I_n)e\leq-(\lambda_{1H}\;-\\ &\frac{\gamma_3\lambda_{N\Pi}}{2})\sum_{i = 1}^N\xi_i^{\mathrm{T}}\xi_i +\frac{1}{2\gamma_3}\sum_{i = 1}^Ne_i^{\mathrm{T}}e_i \end{split} \end{equation} $$ (21) 式中, $e=[e_1^{\mathrm{T}},\;\cdots,\;e_N^{\mathrm{T}}]^{\mathrm{T}} $, $ \Pi = QL^2(L^{2})^{\mathrm{T}}Q $, $ \gamma_3\in (0, \;2\lambda_{1H}/\lambda_{N\Pi}) $.
将式(19) ~ 式(21)代入$ \dot{V}_3 $, 可得:
$$ \begin{equation*} \begin{aligned} \dot{V}_3\leq&-\sum_{i = 1}^N\frac{\rho_ik_1}{k_2}\xi_{ix}^{\mathrm{T}}\xi_{ix}-\sum_{i = 1}^N\left( \frac{ck_2(2\lambda_{1H}-\gamma_3\lambda_{N\Pi})}{2}\;-\right.\\ &\left.\frac{k_1}{q_ik_2}-\frac{(\gamma_1+\gamma_2)k_2\lambda_{N\Xi}}{2}\right)\xi_i^{\mathrm{T}}\xi_i +\frac{ck_2}{2\gamma_3}\sum_{i = 1}^Ne_i^{\mathrm{T}}e_i\;+\\ &\frac{k_2}{2\gamma_1}\sum_{i = 1}^N\phi_i^{\mathrm{T}}\tilde{\theta}_i\tilde{\theta}_i^{\mathrm{T}}\phi_i +\frac{k_2}{2\gamma_2}\sum_{i = 1}^N\phi^{\mathrm{T}}\tilde{\theta}_0^{i}(\tilde{\theta}_0^{i})^{\mathrm{T}}\phi \end{aligned} \end{equation*} $$ 记$ q_{\min} = \min_{i\in\{1,\;\cdots,\;N\}}q_i $. 选取合适的参数$ k_1,\; k_2,\;\gamma_1,\;\gamma_2>0 $, $ \gamma_3\in(0,\;2\lambda_{1H}/\lambda_{N\Pi}) $, $ c>\bar{c} $, 其中:
$$ \begin{equation} \bar{c} = \frac{(\gamma_1+\gamma_2)k_2^2\lambda_{N\Xi}+\frac{2k_1}{q_{\min}}} {(2\lambda_{1H}-\gamma_3\lambda_{N\Pi})k_2^2} \end{equation} $$ (22) 记$ \alpha = k_2(2\lambda_{1H}-\gamma_3\lambda_{N\Pi})(c-\bar{c})/2 $, 可得:
$$ \begin{equation*} \begin{aligned} \dot{V}_3\leq&-\sum_{i = 1}^N\frac{\rho_ik_1}{k_2}\xi_{ix}^{\mathrm{T}}\xi_{ix}-\sum_{i = 1}^N\alpha\xi_i^{\mathrm{T}}\xi_i +\frac{ck_2}{2\gamma_3}\sum_{i = 1}^Ne_i^{\mathrm{T}}e_i\;+\\ &\frac{k_2}{2\gamma_1}\sum_{i = 1}^N\phi_i^{\mathrm{T}}\tilde{\theta}_i\tilde{\theta}_i^{\mathrm{T}}\phi_i +\frac{k_2}{2\gamma_2}\sum_{i = 1}^N\phi^{\mathrm{T}}\tilde{\theta}_0^{i}(\tilde{\theta}_0^{i})^{\mathrm{T}}\phi \end{aligned} \end{equation*} $$ 由于$ \lim_{t\rightarrow\infty}\tilde{\theta}_i(t) = \bf 0,\;\lim_{t\rightarrow\infty}\tilde{\theta}_0^i (t) = \bf 0 $, $\phi_i(x_i (t), \; y_i (t)) $, $ \phi(t) $有界, 结合触发函数可知存在函数$ \beta(t) \in {\cal{A}}(t) $, 使得:
$$ \begin{aligned} \beta(t)\geq\;&\frac{ck_2}{2\gamma_3}\sum_{i = 1}^Ne_i^{\mathrm{T}}e_i +\frac{k_2}{2\gamma_1}\sum_{i = 1}^N\phi_i^{\mathrm{T}}\tilde{\theta}_i\tilde{\theta}_i^{\mathrm{T}}\phi_i\;+\\ &\frac{k_2}{2\gamma_2}\sum_{i = 1}^N\phi^{\mathrm{T}}\tilde{\theta}_0^{i}(\tilde{\theta}_0^{i})^{\mathrm{T}}\phi \end{aligned} $$ 即
$$ \begin{equation} \dot{V}_3\leq-h V_3+\beta(t) \end{equation} $$ (23) 式中, $ h = \min\{2k_1/k_2,\;2\alpha q_{\min}\} $. 由引理1可知, $ V_3(t) $渐近趋向$ \bf 0 $, 即对任意$ i\in\{1,\;\cdots,\;N\} $, 都有
$$ \lim_{t\rightarrow\infty} \xi_{ix}(t) = \xi_{iy}(t) = \bf 0 $$ 记:
$$ \begin{equation*} \begin{aligned} &\xi_x = [\xi_{1x}^{\mathrm{T}},\;\cdots,\;\xi_{Nx}^{\mathrm{T}}]^{\mathrm{T}},\;\delta_x = [\delta_{1x}^{\mathrm{T}},\;\cdots,\;\delta_{Nx}^{\mathrm{T}}]^{\mathrm{T}}\\ &\xi_y = [\xi_{1y}^{\mathrm{T}},\;\cdots,\;\xi_{Ny}^{\mathrm{T}}]^{\mathrm{T}},\;\delta_y = [\delta_{1y}^{\mathrm{T}},\;\cdots,\;\delta_{Ny}^{\mathrm{T}}]^{\mathrm{T}}\\ &\delta_{ix} = x_i-x_0,\;\delta_{iy} = y_i-y_0,\;i = 1,\;\cdots,\;N \end{aligned} \end{equation*} $$ 由$ \xi_{ix} $ 和$\; \xi_{iy} $的定义易证 $\xi_x = (L\otimes I_n)\delta_x,\;\xi_y = (L\otimes I_n)\delta_y$. 当假设1成立时, 则$ L $非奇异. 由式(23)可得, 对任意$i $有$ \lim_{t\rightarrow\infty} x_i(t) = x_0(t),\; y_i(t) = y_0(t) $.
□ 定理2. 分布式事件触发趋同算法式(8)和式(9)不存在芝诺现象.
证明. 当$ t\in[t_k^i,\;t_{k+1}^i) $时, $ \epsilon_i(t) $的Frobenius范数和$ e_i(t) $的2范数的Dini导数满足如下不等式:
$$ \begin{equation*} {\rm D}^+||\epsilon_i(t)||_{\rm{F}}\leq||\dot{\epsilon}_i(t)||_{\rm{F}},\; {\rm D}^+||e_i(t)||\leq||\dot{e}_i(t)|| \end{equation*} $$ 由式(6)和式(7)可得:
$$ \begin{aligned} \dot{\epsilon}_i(t) =\; &\mu\sum_{j = 0}^Na_{ij}(\hat{\theta}_0^i(t_k^i)-\hat{\theta}_0^j(t_{k'}^j))\\ \dot{e}_i(t) =\; &k_2((\hat{\theta}_0^{i})^{\mathrm{T}}\phi(t)-\theta_i^{\mathrm{T}}\phi_i-u_i)\;+\\ &k_1(\hat{y}_i^i(t)-y_i) \end{aligned} $$ 由假设2、命题1、命题2和定理1可知, 存在有界实数$ \psi_k^i>0,\;\chi_k^i $和$ c>0 $, 使得:
$$ \begin{aligned} &{\mathrm{D}}^+||\epsilon_i(t)||_{\rm{F}}\leq\psi_k^i\\ &{\mathrm{D}}^+||e_i(t)||\leq c||e_i(t)||+\chi_k^i \end{aligned} $$ 在事件触发时刻$ t_k^i $, $ \epsilon_i(t) $和$ e_i(t) $被重置为$ \bf 0 $. 对于$ t\in[t_k^i,\;t_{k+1}^i) $, 由比较原理可得:
$$ \begin{equation} \left\{\begin{aligned} &||\epsilon_i(t)||_{\rm{F}}\leq\psi_k^i(t-t_k^i)\\ &||e_i(t)||\leq\frac{\chi_k^i}{c}(\mathrm{e}^{c(t-t_k^i)}-1) \end{aligned}\right. \end{equation} $$ (24) $ \forall t \in [t_k^i,\;t_{k+1}^i) $, 有$ ||\epsilon_i(t)||_{\rm{F}} < \sqrt{f_{i1}(t)},\;||e_i (t)|| < \sqrt{f_{i2}(t)} $.
当$ {t \rightarrow t_{k+1}^i} $时, 则有$ \lim_{t\rightarrow t_{k+1}^i}||e_i(t)||\geq\sqrt{f_{i2}(t)} $, 或$\lim_{t\rightarrow t_{k+1}^i}||\epsilon_i(t)||_{\rm{F}}\geq\sqrt{f_{i1}(t)}$. 结合式(24), 可得$ t_{k+1}^i - t_k^i \geq \ln\left({c}\sqrt{f_{i2}(t)}/{\chi_k^i} + 1\right)/{c} $ 或 $ t_{k+1}^i - t_k^i \; \geq {\sqrt{f_{i1}(t)}}/ {\psi_k^i} $. 对任意有限时间$ t $, $ f_{i1}(t)>0, \;f_{i2}(t)> 0 $, 即连续2次触发时刻的时间差$ t_{k+1}^i-t_k^i $是严格大于$ 0 $的, 从而证明, 对任意有限时间$ t $, 事件触发趋同算法式(8)和式(9)不存在芝诺现象.
□ 推论1. 事件触发条件(10)所给出的领导智能体的事件触发算法不存在芝诺现象. 证明过程与定理 2 证明类似.
4. 数值仿真
本节通过仿真模型验证事件触发控制器式(8)和式(9)的有效性. 考虑包含$ 5 $个智能体的异构不确定二阶非线性多智能体系统, 其中跟随智能体1 ~ 4为无阻尼单摆系统, 其动力学方程为:
$$ \begin{equation} \left\{\begin{aligned} \dot{x}_i& = y_i\\ \dot{y}_i& = -\frac{g}{l_i}\sin(x_i)+u_i \end{aligned}\right. \end{equation} $$ (25) 式中, $ x_i $为单摆的角位移, $ y_i $为角速度, $ g $为重力加速度, $ l_i $为摆长, $ u_i $为控制输入. 由于测量误差原因, 重力加速度$ g $和摆长$\; l_i $的精确值不确定. 领导智能体的动力学方程为:
$$ \begin{equation} \left\{\begin{aligned} \dot{x}_0& = y_0\\ \dot{y}_0& = \theta_0^{\mathrm{T}}\phi(t) \end{aligned}\right. \end{equation} $$ (26) 式中, $ \phi(t) = [\sin(t),\;\cos(2t)]^{\mathrm{T}} $为已知时间向量函数, $ \theta_0\in {\bf{R}}^2 $为未知常向量. 多智能体系统式(25)和式(26)的网络拓扑由如下拉普拉斯矩阵描述:
$$ \begin{equation*} {\cal{L}} =\left[ \begin{array}{*{20}{r}} 0\;\;\;\;\,\,&0\;\;\;\;\,\,&0\;\;\;\;\,\,&0\;\;\;\;\,\,&0\;\;\;\;\,\,\\ 0\;\;\;\;\,\,&0.60&-0.55&0\;\;\;\;\,\,&-0.05\\ -0.50&0\;\;\;\;\,\,&0.55&-0.05&0\;\;\;\;\,\,\\ -0.50&-0.05&0\;\;\;\;\,\,&0.55&0\;\;\;\;\,\,\\ 0\;\;\;\;\,\,&0\;\;\;\;\,\,&0\;\;\;\;\,\,&-0.55&0.55 \end{array}\right] \end{equation*} $$ 根据参数观测器式(4)和式(6), 为每个智能体设计未知向量$ \theta_0 $的观测值$ \hat{\theta}_0^i $; 根据参数观测器式(5), 为跟随智能体设计不确定系数$ -g/l_i $的观测值$ \hat{\theta}_i $, 其中参数$ \mu = 2,\;\rho_i = 1 $; 根据状态估计器式(7), 为每个智能体设计邻居状态估计器. 通过计算, 可求得参数$ q_{\min} \,= \,2.015\ 3,\;\lambda_{1H} = 0.099\ 3,\; \lambda_{N\Xi} \,= 0.103\ 5,\;\lambda_{N\Pi} = 0.056\ 7 $. 通过选取参数$ \gamma_1 = \gamma_2 = \gamma_3 = 0.5 $, $ k_1 = 0.5,\;k_2 = 2 $, 可求得$ c' = 1.336\ 6 $. 因此, 选取事件触发控制器的参数为$ k_1 = 0.5,\; k_2 = 2, \;c \,= 2 $. 对于触发函数式(9)和式(10), 选取函数$ f_{i1}(t) \,= f_{i2}(t) = 0.1/(1+0.5t) $.
仿真结果如图1 ~ 图3所示. 由图1可知, 跟随智能体的角度和角速度渐近跟踪上领导智能体的状态; 由图2可知, $ \hat{\theta}_0^i $和$ \hat{\theta}_i $分别可以渐近收敛到$ \theta_0 $和$ -g/l_i $; 图3给出了各智能体的事件触发时刻. 表1为在时间段$ [0,\;40] $ s内, 本文算法的事件触发次数. 作为对比, 利用文献[8−10, 14] 所给出的组合测量事件触发算法对系统式(25)和式(26) 进行仿真, 表2为在时间段$ [0,\;40] $ s内, 组合测量事件触发算法的各智能体事件触发次数. 可以看出, 本文基于参数和状态观测器的事件触发控制算法可有效减少事件触发次数.
表 1 本文算法的事件触发次数Table 1 Event-triggered number of the proposed algorithm智能体 0 1 2 3 4 触发次数 49 84 75 73 72 表 2 组合测量算法的事件触发次数Table 2 Event-triggered number of the combined measurement algorithm智能体 0 1 2 3 4 触发次数 139 258 266 255 249 5. 结束语
本文基于参数估计与事件触发机制, 研究了异构不确定二阶非线性多智能体系统的状态趋同问题, 给出完全不依赖智能体间连续信息传输的事件触发趋同算法. 因为每个智能体均存在不确定参数, 在设计控制器前, 先设计观测器, 估计其不确定参数. 为使跟随智能体跟踪上领导智能体, 设计分布式参数观测器, 使每个跟随智能体可以渐近估计领导智能体不确定参数. 为使算法达到完全不依赖智能体间连续信息传输的目的, 每个智能体利用其邻居智能体发送的事件触发时刻采样信息, 对邻居智能体状态进行重构, 利用重构的状态信息设计控制器和事件触发函数. 进一步证明了所提事件触发趋同算法不存在芝诺现象. 最后, 通过一个多单摆系统验证了所提事件触发趋同算法的有效性, 同时对比组合测量事件触发算法, 本文所提算法可有效减少事件触发次数. 为简化反馈增益参数对拓扑网络全局信息的依赖, 未来可将现有工作推广到完全分布式事件触发状态趋同控制.
附录 A. 矩阵迹的2个引理
引理 2. 对于空间$ {\bf{R}}^{m\times n} $中的矩阵$ X $, 以及空间$ {\bf{R}}^{m\times m} $中的正定矩阵$ A $, 有:
$$ \lambda_{1A}\mathrm{tr}\{X^{\mathrm{T}}X\}\leq\mathrm{tr}\{X^{\mathrm{T}}AX\}\leq\lambda_{mA}\mathrm{tr}\{X^{\mathrm{T}}X\} $$ 证明. 矩阵$ X $可用 $ n $个列向量 $ x_i\in {\bf{R}}^m, \;i = 1,\;\cdots,\; n $表示, 即$ X = [x_1,\;\cdots,\;x_n] $. 因此, 可得:
$$ \begin{equation*} X^{\mathrm{T}}X = \begin{bmatrix} x_1^{\mathrm{T}}x_1 & x_1^{\mathrm{T}}x_2 & \cdots & x_1^{\mathrm{T}}x_n \\ x_2^{\mathrm{T}}x_1 & x_2^{\mathrm{T}}x_2 & \cdots & x_2^{\mathrm{T}}x_n \\ \vdots & \vdots & \ddots & \vdots \\ x_n^{\mathrm{T}}x_1 & x_n^{\mathrm{T}}x_2 & \cdots & x_n^{\mathrm{T}}x_n \\ \end{bmatrix} \end{equation*} $$ 即, $ \mathrm{tr}\{X^{\mathrm{T}}X\} = \sum_{i = 1}^nx_i^{\mathrm{T}}x_i $.
记$ \Lambda = \mathrm{diag}\{\lambda_{1A},\;\cdots,\;\lambda_{mA}\} $. 由于$ A $为正定矩阵, 所以存在单位正交矩阵$ P\in {\bf{R}}^{m\times m} $使$ P^{\mathrm{T}}AP \;= \Lambda $. 矩阵$ P $可用$ m $个列向量$ p_i\in {\bf{R}}^m, \;i = 1,\;\cdots,\;n $表示, 即$ P = [p_1,\;\cdots,\;p_m] $. 对于$ X^{\mathrm{T}}AX $, 有:
$$ X^{\mathrm{T}}AX = X^{\mathrm{T}}PP^{\mathrm{T}}APP^{\mathrm{T}}X = X^{\mathrm{T}}P\Lambda P^{\mathrm{T}}X $$ 通过计算, 可得:
$$ X^{\mathrm{T}}P\Lambda = \begin{bmatrix} \lambda_{1A}x_1^{\mathrm{T}}p_1 & \lambda_{2A}x_1^{\mathrm{T}}p_2 & \cdots & \lambda_{mA}x_1^{\mathrm{T}}p_m \\ \lambda_{1A}x_2^{\mathrm{T}}p_1 & \lambda_{2A}x_2^{\mathrm{T}}p_2 & \cdots & \lambda_{mA}x_2^{\mathrm{T}}p_m \\ \vdots & \vdots & \ddots & \vdots \\ \lambda_{1A}x_n^{\mathrm{T}}p_1 & \lambda_{2A}x_n^{\mathrm{T}}p_2 & \cdots & \lambda_{mA}x_n^{\mathrm{T}}p_m \\ \end{bmatrix} $$ $$ P^{\mathrm{T}}X = \begin{bmatrix} p_1^{\mathrm{T}}x_1 & p_1^{\mathrm{T}}x_2 & \cdots & p_1^{\mathrm{T}}x_n \\ p_2^{\mathrm{T}}x_1 & p_2^{\mathrm{T}}x_2 & \cdots & p_2^{\mathrm{T}}x_n \\ \vdots & \vdots & \ddots & \vdots \\ p_m^{\mathrm{T}}x_1 & p_m^{\mathrm{T}}x_2 & \cdots & p_m^{\mathrm{T}}x_n \\ \end{bmatrix} $$ 通过计算, 可得:
$$ \mathrm{tr}\{X^{\mathrm{T}}AX\} = \sum\limits_{i = 1}^n\sum\limits_{j = 1}^m\lambda_{jA}x_i^{\mathrm{T}}p_jp_j^{\mathrm{T}}x_i $$ 由于向量组 $ \{p_1,\;\cdots,\;p_m\} $ 为空间 $ {\bf{R}}^m $ 中的一组标准正交基, 所以对数量积$ x_i^{\mathrm{T}}p_j $有 $ x_i^{\mathrm{T}}p_j = ||x_i||\cos\theta_{ij} $, 其中$ \theta_{ij} $为向量 $ x_i $与基向量$ p_j $的夹角. 因此有:
$$ \sum\limits_{j = 1}^m\lambda_{jA}x_i^{\mathrm{T}}p_jp_j^{\mathrm{T}}x_i = \sum\limits_{j = 1}^m\lambda_{jA}(\cos^2\theta_{ij})x_i^{\mathrm{T}}x_i $$ 又由于$ \lambda_{1A}\leq\cdots\leq\lambda_{mA} $和$ \sum_{j = 1}^m\cos^2\theta_{ij} = 1 $, 可得$ \lambda_{1A}\mathrm{tr}\{X^{\mathrm{T}}X\}\leq\mathrm{tr}\{X^{\mathrm{T}}AX\}\leq\lambda_{mA}\mathrm{tr}\{X^{\mathrm{T}}X\}. $
□ 引理 3. 对矩阵$ X\in {\bf{R}}^{m\times n} $, $ Y\in {\bf{R}}^{s\times n} $, $ A\in {\bf{R}}^{m\times s} $和正实数$ \eta $, 有:
$$ \mathrm{tr}\{X^{\mathrm{T}}AY\}\leq\frac{\eta}{2}\mathrm{tr}\{X^{\mathrm{T}}AA^{\mathrm{T}}X\}+\frac{1}{2\eta} \mathrm{tr}\{Y^{\mathrm{T}}Y\} $$ 证明. $ X $, $ Y $, $ A $可表示为:
$$ \begin{aligned} X& = [x_1,\;\cdots,\;x_n],\;x_i\in {\bf{R}}^m,\;i\in\{1,\;\cdots,\;n\}\\ Y& = [y_1,\;\cdots,\;y_n],\;y_i\in {\bf{R}}^s,\;i\in\{1,\;\cdots,\;n\}\\ A& = [a_1,\;\cdots,\;a_s],\;a_i\in {\bf{R}}^m,\;i\in\{1,\;\cdots,\;s\}\\ \end{aligned} $$ 记$ y_i = [y_{i1},\;\cdots,\;y_{is}]^{\mathrm{T}} $, 通过计算可得:
$$ \mathrm{tr}\{X^{\mathrm{T}}AY\} = \sum\limits_{i = 1}^n\sum\limits_{j = 1}^sx_ia_jy_{ij} $$ 根据Young不等式, 可知$ x_ia_jy_{ij}\leq {\eta}(x_ia_j)^2/{2}+ y_{ij}^2/ {2\eta} $, 可得:
$$ \mathrm{tr}\{X^{\mathrm{T}}AY\}\leq\frac{\eta}{2}\sum\limits_{i = 1}^n\sum\limits_{j = 1}^s(x_ia_j)^2+\frac{1}{2\eta} \sum\limits_{i = 1}^n\sum\limits_{j = 1}^sy_{ij}^2 $$ 容易验证$ \sum_{i = 1}^n\sum_{j = 1}^s(x_ia_j)^2 \,=\, \mathrm{tr}\{X^{\mathrm{T}}AA^{\mathrm{T}}X\} ,$ $ \sum_{i = 1}^n \sum_{j = 1}^sy_{ij}^2 = \mathrm{tr}\{Y^{\mathrm{T}}Y\} $.
□ -
表 1 1号风机与1号光机未来时段预测结果
Table 1 Prediction results of No.1 wind generator and No.1 solar generator
预测时段 1号风机 1号光机 时段1 时段2 时段3 时段1 时段2 时段3 RMSE 17.383 25.569 32.469 10.703 12.787 13.645 平均误差 12.2974 19.3473 26.2758 6.2836 9.2977 11.2038 平均误差率 0.0416 0.0649 0.0878 0.0197 0.0292 0.0354 表 2 2 ~ 5 号风机未来时段预测结果
Table 2 Prediction results of No. 2 ~ 5 wind generators
预测时段 2号风机 3号风机 时段1 时段2 时段3 时段1 时段2 时段3 RMSE 22.869 30.357 34.298 22.842 31.128 34.999 平均误差 16.4035 23.7910 27.1607 16.4035 23.7910 27.1607 平均误差率 0.0870 0.1290 0.1489 0.0813 0.1209 0.1291 预测时段 4号风机 5号风机 时段1 时段2 时段3 时段1 时段2 时段3 RMSE 25.314 37.057 41.635 28.273 37.187 44.354 平均误差 22.0610 27.7490 33.7304 20.1751 28.2186 33.6929 平均误差率 0.0770 0.0954 0.1169 0.0696 0.0974 0.1138 表 3 2 ~ 5 号光机未来时段预测结果
Table 3 Prediction results of No. 2 ~ 5 solar generators
预测时段 2号光机 3号光机 时段1 时段2 时段3 时段1 时段2 时段3 RMSE 6.778 14.388 19.350 9.624 11.194 14.049 平均误差 5.5040 13.3298 16.5947 10.3386 11.2576 13.0231 平均误差率 0.0187 0.0454 0.0566 0.0333 0.0365 0.0424 预测时段 4号光机 5号光机 时段1 时段2 时段3 时段1 时段2 时段3 RMSE 9.467 9.549 14.924 7.149 8.264 17.235 平均误差 7.6231 12.4947 15.6101 8.6143 7.6891 9.6818 平均误差率 0.0242 0.0398 0.0500 0.0301 0.0272 0.0344 表 4 风机与光机未来时段预测平均结果
Table 4 Average results of wind and solar generators
预测时段 $1\sim 5 $ 号风机$1\sim 5 $ 号光机时段1 时段2 时段3 时段1 时段2 时段3 平均RMSE 23.336 32.260 37.551 8.744 11.236 15.841 平均误差 17.5651 24.8910 29.6411 7.6727 10.8138 13.2227 平均误差率 0.0713 0.1015 0.1193 0.0252 0.0356 0.0438 表 5 开停机和穿越振动区次数对比
Table 5 Comparison of times of on/off and crossing vibration areas
调度方式 开停机次数 穿越振动区次数 平均分配调度 6 30 AGC模拟调度 3 4 -
[1] Xia Y Q, Gao Y L, Yan L P, Fu M Y. Recent progress in networked control systems—a survey. International Journal of Automation and Computing, 2015, 12(4): 343−367 doi: 10.1007/s11633-015-0894-x [2] Zhang X M, Han Q L, Yu X H. Survey on recent advances in networked control systems. IEEE Transactions on Industrial Informatics, 2016, 12(5): 1740−1752 doi: 10.1109/TII.2015.2506545 [3] Wang S Y, Wan J F, Zhang D Q, Li D, Zhang C H. Towards smart factory for industry 4.0: A self-organized multi-agent system with big data based feedback and coordination. Computer Networks, 2016, 101: 158−168 doi: 10.1016/j.comnet.2015.12.017 [4] Hegazy T, Hefeeda M. Industrial automation as a cloud service. IEEE Transactions on Parallel and Distributed Systems, 2015, 26(10): 2750−2763 doi: 10.1109/TPDS.2014.2359894 [5] Xia Y Q. From networked control systems to cloud control systems. In: Proceedings of the 31st Chinese Control Conference. Hefei, China: IEEE, 2012. 5878−5883 [6] Xia Y Q. Cloud control systems. IEEE/CAA Journal of Automatica Sinica, 2015, 2(2): 134−142 doi: 10.1109/JAS.2015.7081652 [7] Xia Y Q, Qin Y M, Zhai D H, Chai S C. Further results on cloud control systems. Science China Information Sciences, 2016, 59(7): 1−5 [8] 夏元清. 云控制系统及其面临的挑战. 自动化学报, 2016, 42(1): 1−12Xia Yuan-Qing. Cloud control systems and their challenges. Acta Automatica Sinica, 2016, 42(1): 1−12 [9] 夏元清, Mahmoud M S, 李慧芳, 张金会. 控制与计算理论的交互: 云控制. 指挥与控制学报, 2017, 3(2): 99−118 doi: 10.3969/j.issn.2096-0204.2017.02.0099Xia Yuan-Qing, Mahmoud M S, Li Hui-Fang, Zhang Jin-Hui. The interaction between control and computing theories: Cloud control system. Journal of Command and Control, 2017, 3(2): 99−118 doi: 10.3969/j.issn.2096-0204.2017.02.0099 [10] Gao R Z, Xia Y Q, Ma L. A new approach of cloud control systems: CCSs based on data-driven predictive control. In: Proceedings of the 5th Chinese Automation Congress (CAC). Jinan, China: IEEE, 2017. 3419−3422 [11] Ali Y, Xia Y Q, Ma L, Hammad A. Secure design for cloud control system against distributed denial of service attack. Control Theory and Technology, 2018, 16(1): 14−24 doi: 10.1007/s11768-018-8002-8 [12] 夏元清, 闫策, 王笑京, 宋向辉. 智能交通信息物理融合云控制系统. 自动化学报, 2019, 45(1): 132−142Xia Yuan-Qing, Yan Ce, Wang Xiao-Jing, Song Xiang-Hui. Intelligent transportation cyber-physical cloud control systems. Acta Automatica Sinica, 2019, 45(1): 132−142 [13] Botta A, De Donato W, Persico V, Pescapé A. Integration of cloud computing and internet of things: A survey. Future Generation Computer Systems, 2016, 56: 684−700 doi: 10.1016/j.future.2015.09.021 [14] Shi W S, Cao J, Zhang Q, Li Y, Xu L Y. Edge computing: Vision and challenges. IEEE Internet of Things Journal, 2016, 3(5): 637−646 doi: 10.1109/JIOT.2016.2579198 [15] Thounthong P, Luksanasakul A, Koseeyaporn P, Davat B. Intelligent model-based control of a standalone photovoltaic/fuel cell power plant with supercapacitor energy storage. IEEE Transactions on Sustainable Energy, 2013, 4(1): 240−249 doi: 10.1109/TSTE.2012.2214794 [16] 刘吉臻, 胡勇, 曾德良, 夏明, 崔青汝. 智能发电厂的架构及特征. 中国电机工程学报, 2017, 37(22): 6463−6470Liu Ji-Zhen, Hu Yong, Zeng De-Liang, Xia Ming, Cui Qing-Ru. Architecture and feature of smart power generation. Proceedings of the CSEE, 2017, 37(22): 6463−6470 [17] Adhya S, Saha D, Das A, Jana J, Saha H. An IoT based smart solar photovoltaic remote monitoring and control unit. In: Proceedings of the 2nd International Conference on Control, Instrumentation, Energy and Communication (CIEC). Kolkata, India: IEEE, 2016. 432−436 [18] Zhan Z H, Liu X F, Gong Y J, Zhang J, Chung H S H, Li Y. Cloud computing resource scheduling and a survey of its evolutionary approaches. ACM Computing Surveys, 2015, 47(4): Article No. 63 [19] Qin Q F, Poularakis K, Iosifidis G, Tassulas L. SDN controller placement at the edge: Optimizing delay and overheads. In: Proceedings of the 37th Conference on Computer Communications. Honolulu, USA: IEEE, 2018. 684−692 [20] Hu L, Miao Y M, Wu G X, Hassan M, Humar I. iRobot-Factory: An intelligent robot factory based on cognitive manufacturing and edge computing. Future Generation Computer Systems, 2019, 90: 569−577 doi: 10.1016/j.future.2018.08.006 [21] 任延明. 新能源集控中心网络设计及云控制实现 [硕士学位论文], 北京理工大学, 中国, 2018.Ren Yan-Ming. Network Design and Cloud Control Implementation of New Energy Centralized Control Center [Master thesis], Beijing Institute of Technology, China, 2018. [22] 马岩岩. 大数据一体化平台在电厂中的研究与应用. 世界电信, 2017, 30(4): 64−71 doi: 10.3969/j.issn.1001-4802.2017.04.013Ma Yan-Yan. Research and application of big data integration platform in power plant. World Telecommunications, 2017, 30(4): 64−71 doi: 10.3969/j.issn.1001-4802.2017.04.013 [23] 耿清华. 浅谈基于大数据的智慧水电厂建设. 水电与新能源, 2018, 32(10): 33−35Geng Qing-Hua. Construction of the intelligent hydropower plant based on big data technology. Hydropower and New Energy, 2018, 32(10): 33−35 [24] 喻敏华. 智慧全析电厂信息平台研究与设计. 电力与能源, 2018, 39(3): 392−396, 408Yu Min-Hua. Research and design of intelligent comprehensive analysis power plant information platform. Power and Energy, 2018, 39(3): 392−396, 408 [25] Khan F A, Pal N, Saeed S H. Review of solar photovoltaic and wind hybrid energy systems for sizing strategies optimization techniques and cost analysis methodologies. Renewable and Sustainable Energy Reviews, 2018, 92: 937−947 doi: 10.1016/j.rser.2018.04.107 [26] 艾芊, 郝然. 多能互补、集成优化能源系统关键技术及挑战. 电力系统自动化, 2018, 42(4): 2−10, 46 doi: 10.7500/AEPS20170927008Ai Qian, Hao Ran. Key technologies and challenges for multi-energy complementarity and optimization of integrated energy system. Automation of Electric Power Systems, 2018, 42(4): 2−10, 46 doi: 10.7500/AEPS20170927008 [27] 赵泽. 风光水互补发电系统有功控制问题研究 [硕士学位论文]. 中国水利水电科学研究院, 中国, 2018.Zhao Ze. Research on the AGC of Complementary Power Generation Pattern of Wind Power, Solar Power and Hydropower [Master thesis], China Institute of Water Resources and Hydropower Research, China, 2018. [28] 陈丽媛, 陈俊文, 李知艺, 庄晓丹. “风光水”互补发电系统的调度策略. 电力建设, 2013, 34(12): 1−6 doi: 10.3969/j.issn.1000-7229.2013.12.001Chen Li-Yuan, Chen Jun-Wen, Li Zhi-Yi, Zhuang Xiao-Dan. Scheduling strategy of wind-photovoltaic-hydro hybrid generation system. Electric Power Construction, 2013, 34(12): 1−6 doi: 10.3969/j.issn.1000-7229.2013.12.001 [29] Taleb T, Samdanis K, Mada B, Flinck H, Dutta S, Sabella D. On multi-access edge computing: A survey of the emerging 5G network edge cloud architecture and orchestration. IEEE Communications Surveys and Tutorials, 2017, 19(3): 1657−1681 doi: 10.1109/COMST.2017.2705720 [30] Xavier M G, Neves M V, Rossi F D, Ferreto T C, Lange T, De Rose C A F. Performance evaluation of container-based virtualization for high performance computing environments. In: Proceedings of the 21st Euromicro International Conference on Parallel, Distributed, and Network-Based Processing. Belfast, United Kingdom: IEEE, 2013. 233−240 [31] Liu G P. Predictive control of networked multiagent systems via cloud computing. IEEE Transactions on Cybernetics, 2017, 47(8): 1852−1859 doi: 10.1109/TCYB.2017.2647820 [32] He X, Ju Y M, Liu Y, Zhang B C. Cloud-based fault tolerant control for a DC motor system. Journal of Control Science and Engineering, 2017, 2017(3): Article ID 5670849 [33] Li L, Wang X J, Xia Y Q, Yang H J. Predictive cloud control for multiagent systems with stochastic event-triggered schedule. ISA Transactions, 2019, 94: 70−79 doi: 10.1016/j.isatra.2019.04.011 [34] Peinl R, Holzschuher F, Pfitzer F. Docker cluster management for the cloud-survey results and own solution. Journal of Grid Computing, 2016, 14(2): 265−282 doi: 10.1007/s10723-016-9366-y [35] 罗军舟, 金嘉晖, 宋爱波, 东方. 云计算: 体系架构与关键技术. 通信学报, 2011, 32(7): 3−21 doi: 10.3969/j.issn.1000-436X.2011.07.002Luo Jun-Zhou, Jin Jia-Hui, Song Ai-Bo, Dong Fang. Cloud computing: Architecture and key technologies. Journal on Communications, 2011, 32(7): 3−21 doi: 10.3969/j.issn.1000-436X.2011.07.002 [36] Xiong Y, Sun Y L, Xing L, Huang Y. Extend cloud to edge with KubeEdge. In: Proceedings of the 2018 IEEE/ACM Symposium on Edge Computing (SEC). Seattle, WA, USA: IEEE, 2018. 373−377 [37] Haja D, Szalay M, Sonkoly B, Pongracz G, Toka L. Sharpening Kubernetes for the edge. In: Proceedings of the ACM SIGCOMM 2019 Conference Posters and Demos. Beijing, China: ACM, 2019. 136−137 [38] Majeed A A, Kilpatrick P, Spence I. Varghese B. Performance estimation of container-based cloud-to-fog offloading. arXiv: 1909.04945, 2019. [39] Tao F, Cheng J F, Qi Q L, Zhang M, Zhang H, Sui F Y. Digital twin-driven product design, manufacturing and service with big data. The International Journal of Advanced Manufacturing Technology, 2018, 94(9-12): 3563−3576 doi: 10.1007/s00170-017-0233-1 [40] Wan J F, Tang S L, Shu Z G, Li D, Wang S Y, Imran M, et al. Software-defined industrial internet of things in the context of industry 4.0. IEEE Sensors Journal, 2016, 16(20): 7373−7380 [41] Wu D, Arkhipov D I, Asmare E, Qin Z J, McCann J A. UbiFlow: Mobility management in urban-scale software defined IoT. In: Proceedings of the 34th IEEE Conference on Computer Communications. Hong Kong, China: IEEE, 2015. 208−216 [42] Chung A, Park J W, Ganger G R. Stratus: Cost-aware container scheduling in the public cloud. In: Proceedings of the 9th ACM Symposium on Cloud Computing. Carlsbad, USA: ACM, 2018. 121−134 [43] Zhang Q, Zhani M F, Boutaba R, Hellerstein J L. Dynamic heterogeneity-aware resource provisioning in the cloud. IEEE Transactions on Cloud Computing, 2014, 2(1): 14−28 doi: 10.1109/TCC.2014.2306427 [44] Bernstein D. Containers and cloud: From LXC to docker to kubernetes. IEEE Cloud Computing, 2014, 1(3): 81−84 doi: 10.1109/MCC.2014.51 [45] Zhu J, Li X P, Ruiz R, Xu X L. Scheduling stochastic multi-stage jobs to elastic hybrid cloud resources. IEEE Transactions on Parallel and Distributed Systems, 2018, 29(6): 1401−1415 doi: 10.1109/TPDS.2018.2793254 [46] Malawski M, Juve G, Deelman E, Nabrzyski J. Algorithms for cost- and deadline-constrained provisioning for scientific workflow ensembles in IaaS clouds. Future Generation Computer Systems, 2015, 48: 1−18 doi: 10.1016/j.future.2015.01.004 [47] Mao H Z, Alizadeh M, Menache I, Kandula S. Resource management with deep reinforcement learning. In: Proceedings of the 15th ACM Workshop on Hot Topics in Networks. Atlanta, USA: ACM, 2016. 50−56 [48] Yuan H H, Xia Y Q, Zhang J H, Yang H J, Mahmoud M S. Stackelberg-game-based defense analysis against advanced persistent threats on cloud control system. IEEE Transactions on Industrial Informatics, 2020, 16(3): 1571−1580 doi: 10.1109/TII.2019.2925035 [49] Zhou J, Cao Z F, Dong X L, Vasilakos A V. Security and privacy for cloud-based IoT: Challenges. IEEE Communications Magazine, 2017, 55(1): 26−33 doi: 10.1109/MCOM.2017.1600363CM [50] Manuel P. A trust model of cloud computing based on quality of service. Annals of Operations Research, 2015, 233(1): 281−292 doi: 10.1007/s10479-013-1380-x [51] Li P, Li J, Huang Z G, Li T, Gao C Z, Yiu S M, et al. Multi-key privacy-preserving deep learning in cloud computing. Future Generation Computer Systems, 2017, 74: 76−85 doi: 10.1016/j.future.2017.02.006 [52] Habib M A, Ahmad M, Jabbar S, Ahmed S H, Rodrigues J J P C. Speeding up the internet of things: LEAIoT: A lightweight encryption algorithm toward low-latency communication for the internet of things. IEEE Consumer Electronics Magazine, 2018, 7(6): 31−37 doi: 10.1109/MCE.2018.2851722 [53] Dragomir D, Gheorghe L, Costea S, Radovici A. A survey on secure communication protocols for IoT systems. In: Proceedings of the 5th International Workshop on Secure Internet of Things (SIoT). Heraklion, Greece: IEEE, 2016. 47−62 [54] Kumari S, Karuppiah M, Das A K, Li X, Wu F, Kumar N. A secure authentication scheme based on elliptic curve cryptography for IoT and cloud servers. The Journal of Supercomputing, 2018, 74(12): 6428−6453 doi: 10.1007/s11227-017-2048-0 [55] 韩璇, 袁勇, 王飞跃. 区块链安全问题: 研究现状与展望. 自动化学报, 2019, 45(1): 206−225Han Xuan, Yuan Yong, Wang Fei-Yue. Security problems on blockchain: The state of the art and future trends. Acta Automatica Sinica, 2019, 45(1): 206−225 [56] Park J, Park J. Blockchain security in cloud computing: Use cases, challenges, and solutions. Symmetry, 2017, 9(8): 164 doi: 10.3390/sym9080164 [57] Khan M A, Salah K. IoT security: Review, blockchain solutions, and open challenges. Future Generation Computer Systems, 2018, 82: 395−411 doi: 10.1016/j.future.2017.11.022 [58] Bahga A, Madisetti V K. Blockchain platform for industrial internet of things. Journal of Software Engineering and Applications, 2016, 9(10): 533−546 doi: 10.4236/jsea.2016.910036 [59] Ahmad I, Kumar T, Liyanage M, Okwuibe J, Ylianttila M, Gurtov A. Overview of 5G security challenges and solutions. IEEE Communications Standards Magazine, 2018, 2(1): 36−43 doi: 10.1109/MCOMSTD.2018.1700063 [60] 金芬兰, 王昊, 范广民, 余建明, 米为民. 智能电网调度控制系统的变电站集中监控功能设计. 电力系统自动化, 2015, 39(1): 241−247 doi: 10.7500/AEPS20141009023Jin Fen-Lan, Wang Hao, Fan Guang-Min, Yu Jian-Ming, Mi Wei-Min. Design of centralized substation monitoring functions for smart grid dispatching and control systems. Automation of Electric Power Systems, 2015, 39(1): 241−247 doi: 10.7500/AEPS20141009023 [61] Zaytar M A, El Amrani C. Sequence to sequence weather forecasting with long short-term memory recurrent neural networks. International Journal of Computer Applications, 2016, 143(11): 7−11 doi: 10.5120/ijca2016910497 [62] Rossiter J. Model-Based Predictive Control: A Practical Approach. Boca Raton: CRC Press, 2017. 52−74 [63] Müller M, Grüne L. Economic model predictive control without terminal constraints for optimal periodic behavior. Automatica, 2016, 70: 128−139 doi: 10.1016/j.automatica.2016.03.024 [64] Zong Y, Böning G M, Santos R M, You S, Hu J J, Han X. Challenges of implementing economic model predictive control strategy for buildings interacting with smart energy systems. Applied Thermal Engineering, 2017, 114: 1476−1486 doi: 10.1016/j.applthermaleng.2016.11.141 [65] 乔亮亮, 李晨坤, 付亮, 唐卫平. 某250MW水电机组振动区划分及AGC避振方法应用. 水电能源科学, 2018, 36(9): 152−154Qiao Liang-Liang, Li Chen-Kun, Fu Liang, Tang Wei-Ping. Vibration zone division of a 250MW hydropower unit and application of AGC vibration avoidance method. Water Resources and Power, 2018, 36(9): 152−154 [66] 邓维, 刘方明, 金海, 李丹. 云计算数据中心的新能源应用: 研究现状与趋势. 计算机学报, 2013, 36(3): 582−598Deng Wei, Liu Fang-Ming, Jin Hai, Li Dan. Leveraging renewable energy in cloud computing datacenters: State of the art and future research. Chinese Journal of Computers, 2013, 36(3): 582−598 [67] 温正楠, 刘继春. 风光水互补发电系统与需求侧数据中心联动的优化调度方法. 电网技术, 2019, 43(7): 2449−2459Wen Zheng-Nan, Liu Ji-Chun. A optimal scheduling method for hybrid wind-solar-hydro power generation system with data center in demand side. Power System Technology, 2019, 43(7): 2449−2459 -