Since unmanned ground vehicles often encounter concave and convex obstacles in wild ground, a filtering algorithm using line structured light to detect these long distance obstacles is proposed. For the line structure...Since unmanned ground vehicles often encounter concave and convex obstacles in wild ground, a filtering algorithm using line structured light to detect these long distance obstacles is proposed. For the line structured light image, a ranked-order based adaptively extremum median （RAEM） filter algorithm on salt and pepper noise is presented. In the algorithm, firstly effective points and noise points in a filtering window are differentiated; then the gray values of noise points are replaced by the medium of gray values of the effective pixels, with the efficient points＇ gray values unchanged; in the end this algorithm is proved to be efficient by experiments. Experimental resuits demonstrate that the image blur, resulting into proposed algorithm can remove noise points effectively and minimize the protecting the edge information as much as possible.展开更多
分析了单相单级光伏逆变器的模型特点及其对最大功率点跟踪(maximum power point tracking,MPPT)控制的特殊要求,提出了适用于这种类型光伏逆变器的MPPT方法。该方法利用极值搜索算法实现MPPT控制,通过高通滤波器提取逆变器直流电压中...分析了单相单级光伏逆变器的模型特点及其对最大功率点跟踪(maximum power point tracking,MPPT)控制的特殊要求,提出了适用于这种类型光伏逆变器的MPPT方法。该方法利用极值搜索算法实现MPPT控制,通过高通滤波器提取逆变器直流电压中的纹波电压,以该纹波电压为极值搜索算法的扰动信号;在极值搜索算法中引入优化补偿环节,通过该环节提高算法的收敛速度,进一步优化MPPT控制的稳态和动态性能。仿真和实验结果表明该方法可以充分利用单相单级逆变器的固有纹波,在无需额外注入扰动信号的前提下,该MPPT方法能够快速准确地搜索到最大功率点。展开更多
针对极值搜索控制系统(Extremum seeking control systems,ESCSs)设计中,极值搜索算法与控制器采取单独设计时易导致系统难以发挥其最佳性能,而现有的一体化设计方法却存在需要根据被控对象和具体的极值搜索算法进行不同形式的一体化建...针对极值搜索控制系统(Extremum seeking control systems,ESCSs)设计中,极值搜索算法与控制器采取单独设计时易导致系统难以发挥其最佳性能,而现有的一体化设计方法却存在需要根据被控对象和具体的极值搜索算法进行不同形式的一体化建模的问题,以块控型的极值搜索控制系统为研究对象,提出了一套通用的极值搜索控制系统的一体化控制方法.首先针对块控型极值搜索控制系统,采用反馈线性化设计思想,构建出系统的伪虚拟控制量;然后以极值搜索算法得到的搜索变量作为其输入量,设计多层神经网络(Multilayer neural networks,MNNs)逼近由近似模型与实际模型之间的差异而导致的误差项、状态变量的极值和极值的变化率,同时运用自适应参数和鲁棒项函数抵消神经网络逼近误差的影响;最后利用反演控制方法求取出系统的虚拟控制量和实际控制量.此一体化控制方法确保系统的状态跟踪误差、输出量与其极值之间的误差、极值搜索变量的跟踪误差以及神经网络各参数的估计误差均有界且指数收敛至系统原点的一个有限邻域内,且理论分析和仿真结果都验证了此方法的有效性.展开更多
基金Supported by the National Natural Science Foundation of China(61273346)the National Defense Key Fundamental Research Program of China(A20130010)the Program for the Fundamental Research of Beijing Institute of Technology(2016CX02010)
文摘Since unmanned ground vehicles often encounter concave and convex obstacles in wild ground, a filtering algorithm using line structured light to detect these long distance obstacles is proposed. For the line structured light image, a ranked-order based adaptively extremum median （RAEM） filter algorithm on salt and pepper noise is presented. In the algorithm, firstly effective points and noise points in a filtering window are differentiated; then the gray values of noise points are replaced by the medium of gray values of the effective pixels, with the efficient points＇ gray values unchanged; in the end this algorithm is proved to be efficient by experiments. Experimental resuits demonstrate that the image blur, resulting into proposed algorithm can remove noise points effectively and minimize the protecting the edge information as much as possible.
文摘分析了单相单级光伏逆变器的模型特点及其对最大功率点跟踪(maximum power point tracking,MPPT)控制的特殊要求,提出了适用于这种类型光伏逆变器的MPPT方法。该方法利用极值搜索算法实现MPPT控制,通过高通滤波器提取逆变器直流电压中的纹波电压,以该纹波电压为极值搜索算法的扰动信号;在极值搜索算法中引入优化补偿环节,通过该环节提高算法的收敛速度,进一步优化MPPT控制的稳态和动态性能。仿真和实验结果表明该方法可以充分利用单相单级逆变器的固有纹波,在无需额外注入扰动信号的前提下,该MPPT方法能够快速准确地搜索到最大功率点。
