共查询到20条相似文献，搜索用时 171 毫秒
1.
Designing reliable flight control for an autonomous helicopter requires a high performance dynamics model.In this paper,a nonlinear autoregressive with exogenous inputs （NLARX） model is selected as the mathematical structure for identifying and controlling the flight of a small-scale helicopter.A neural network learning algorithm is combined with the NLARX model to identify the dynamic component of the rotorcraft unmanned aerial vehicle （RUAV）.This identification process is based on the well-known gradient descent learning algorithm.As a case study,the multiple-input multiple-output （MIMO） model predictive control （MPC） is applied to control the pitch motion of the helicopter.Results of the neural network output model are closely match with the real flight data.The MPC also shows good performance under various conditions. 相似文献
2.
A channel estimation approach for orthogonal frequency division multiplexing with multiple-input and multipleoutput （MIMO-OFDM） in rapid fading channels is proposed. This approach combines the advantages of an optimal training sequence based least-square （OLS） algorithm and an expectation-maximization （EM） algorithm. The channels at the training blocks are estimated using an estimator based on the OLS algorithm. To compensate for the fast Rayleigh fading at the data blocks, a time domain based Gaussian interpolation filter is presented. Furthermore, an EM algorithm is introduced to improve the performance of channel estimation by a few iterations. Simulations show that this channel estimation approach can effectively track rapid channel variation. 相似文献
3.
In order to improve parts accuracy, a method of adding heat balance support （HBS） was proposed, and the detailed algorithm for generating HBS was developed. A number of experiments and a comparison between similar softwares, showed that the algorithm is efficient and feasible. Moreover, different features of riBS were studied for different kinds of materials, such as PS and nylon. The research findings indicate that automatically adding HBS can significantly improve the accuracy of the parts, and that the algorithm for generating HBS is efficient and precise. 相似文献
4.
In this paper, a new primal-dual interior-point algorithm for convex quadratic optimization (CQO) based on a kernel function is presented. The proposed function has some properties that are easy for checking. These properties enable us to improve the polynomial complexity bound of a large-update interior-point method (IPM) to O (√nlognlogn/ε), which is the currently best known polynomial complexity bound for the algorithm with the large-update method. Numerical tests were conducted to investigate the behavior of the algorithm with different parameters p, q and θ, where p is the growth degree parameter, q is the barrier degree of the kernel function and θ is the barrier update parameter. 相似文献
5.
Satellite attitude information is essential for pico-satellite applications requiring light-weight, low-power, and fast-computation characteristics. The objective of this study is to provide a magnetometer-only attitude estimation method for a low-altitude Earth orbit, bias momentum pico-satellite. Based on two assumptions, the spacecraft spherical symmetry and damping of body rates, a linear kinematics model of a bias momentum satellite＇s pitch axis is derived, and the linear estimation algorithm is developed. The algorithm combines the linear Kalman filter （KF） with the classic three-axis attitude determination method （TRIAD）. KF is used to estimate satellite＇s pitch axis orientation, while TRIAD is used to obtain information concerning the satellite＇s three-axis attitude. Simulation tests confirmed that the algorithm is suited to the time-varying model errors resulting from both assumptions. The estimate result keeps tracking satellite attitude motion during all damping, stable, and free rotating control stages. Compared with nonlinear algorithms, such as extended Kalman filer （EKF） and square root unscented Kalman filer （SRUKF）, the algorithm presented here has an almost equal performance in terms of convergence time and estimation accuracy, while the consumption of computing resources is much lower. 相似文献
6.
Acoustic Doppler current profiler （ADCP） uses acoustic energy directed along narrow beams for current measurement. In conventional method, the quantity of sampling affects the precision of fast Fourier transform （FFT） algorithm, and the algorithm needs a large amount of data to process. A novel frequency estimator.enhanced least mean square （ELMS） algorithm for a single complex sinusoid in complex white Gaussian noise, is proposed in ADCP system. As sampling frequency equals 120 krad/s and the sampling number equals 240. the minimum resolving is 0. 5 krad/s. All variances keep 11.11%. ELMS algorithm needs less data than FFT. And the robust algorithm can estimate the spectrum true value to 99.9% when the signal to noise ratio （SNR） is equal to 0 dB. Experiments prove that the estimation values will diverge much from the ideal when SNR is less than -6 dB. 相似文献
7.
An immune-tabu hybrid algorithm for thermal unit commitment of electric power systems 总被引：1，自引：0，他引：1
This paper presents a new method based on an immune-tabu hybrid algorithm to solve the thermal unit commitment （TUC） problem in power plant optimization. The mathematical model of the TUC problem is established by analyzing the generating units in modem power plants. A novel immune-tabu hybrid algorithm is proposed to solve this complex problem. In the algorithm, the objective function of the TUC problem is considered as an antigen and the solutions are considered as antibodies, which are determined by the affinity computation. The code length of an antibody is shortened by encoding the continuous operating time, and the optimum searching speed is improved. Each feasible individual in the immune algorithm （IA） is used as the initial solution of the tabu search （TS） algorithm after certain generations of IA iteration. As examples, the proposed method has been applied to several thermal unit systems for a period of 24 h. The computation results demonstrate the good global optimum searching performance of the proposed immune-tabu hybrid algorithm. The presented algorithm can also be used to solve other optimization problems in fields such as the chemical industry and the power industry. 相似文献
8.
LIU Guang-hui CHEN Chuan-bo 《浙江大学学报(A卷英文版)》2007,8(8):1210-1217
When the edges of a convex polygon are traversed along one direction,the interior of the convex polygon is always on the same side of the edges. Based on this characteristic of convex polygons,a new algorithm for computing the convex hull of a simple polygon is proposed in this paper,which is then extended to a new algorithm for computing the convex hull of a planar point set. First,the extreme points of the planar point set are found,and the subsets of point candidate for vertex of the convex hull between extreme points are obtained. Then,the ordered convex hull point sequences between extreme points are constructed separately and concatenated by removing redundant extreme points to get the convex hull. The time complexity of the new planar convex hull algorithm is O(nlogh) ,which is equal to the time complexity of the best output-sensitive planar convex hull algorithms. Compared with the algorithm having the same complexity,the new algorithm is much faster. 相似文献
9.
Parameters optimization and nonlinearity analysis of grating eddy current displacement sensor using neural network and genetic algorithm 总被引：1，自引：0，他引：1
A grating eddy current displacement sensor （GECDS） can be used in a watertight electronic transducer to realize long range displacement or position measurement with high accuracy in difficult industry conditions. The parameters optimization of the sensor is essential for economic and efficient production. This paper proposes a method to combine an artificial neural network （ANN） and a genetic algorithm （GA） for the sensor parameters optimization. A neural network model is developed to map the complex relationship between design parameters and the nonlinearity error of the GECDS, and then a GA is used in the optimization process to determine the design parameter values, resulting in a desired minimal nonlinearity error of about 0.11%. The calculated nonlinearity error is 0.25%. These results show that the proposed method performs well for the parameters optimization of the GECDS. 相似文献
10.
This paper presents the forward displacement analysis of an 8-PSS （prismatic-spherical-spherical） redundant parallel manipulator whose moving platform is linked to the base platform by eight kinemtic chains consisting of a PSS joint and a strut with fixed length. A general approximation algorithm is used to solve the problem. To avoid the extraction of root in the approximation process, the forward displacement analysis of the 8-PSS redundant parallel manipulator is transformed into another equivalent problem on the assumption that the strut is extensible while the slider is fixed. The problem is solved by a modified approximation algorithm which predicates that the manipulator will move along a pose vector to reduce the difference between the desired configuration and an instantaneous one, and the best movement should be with minimum norm and least quadratic sum. The characteristic of this modified algorithm is that its convergence domain is larger than that of the general approximation algorithm. Simulation results show that the modelified algorithm is general and can be used for the forward displacement analysis of the redundant parallel manipulator actuated by a revolute joint. 相似文献
11.
g-r循环矩阵求逆的快速算法和并行算法 总被引：1，自引：0，他引：1
袁中扬 《咸阳师范学院学报》2007,22(6):1-3
借助于快速付立叶变换(FFT),给出了n阶g-r循环矩阵求逆的快速算法,该算法的计算复杂性为O(nlogn) (g 1)n,且具有很好的并行性,若使用n台处理机并行处理该算法,则只需要O(nlogn) (g 1)n步。 相似文献
12.
互联网络RCP(Ringed Crossed cube Petersen)拓扑结构被提出后并没有给出组播算法.本文利用RCP(n)网络的正则性、良好的可扩展性,以及比Qn,HP(n),RHP(n)网络直径更短和构造开销更小这些特性,按照构造组播树的方法,给出了RCP(n)网络的组播路由算法,并对该算法作了性能分析. 相似文献
13.
This paper presents an efficient parallel algorithm for the shortest-path problem in interval graph for computing shortest-paths in a weighted interval graph that runs in O(n) time with n intervals in a graph. A linear processor CRCW algorithm for determining the shortest-paths in an interval graphs is given. 相似文献
14.
This paper presents an efficient parallel algorithm for the shortest-path problem in interval graph for computing shortest-paths in a weighted interval graph that runs in O(n) time with n intervals in a graph. A linear processor CRCW algorithm for determining the shortest-paths in an interval graphs is given. 相似文献
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16.
M序列是非常重要的伪随机序列．给出了2元n级M序列的一个新的递归算法，该算法所需存储空间约为4n比特．而且只要经过一些修改便可生成大量的M序列． 相似文献
17.
讨论在模n=2k剩余类环上求逆元的算法.文中引入阶的概念.利用元素的阶,文中给出求逆元的左位移算法,该算法时间复杂度为O(log2n)=O(k). 相似文献
18.
唐自立 《南通职业大学学报》2014,(4):93-98
提出一种新的由一棵严格二叉树的后序序列和结点的双亲情况构造该严格二叉树的非递归算法。通过实例说明该算法的执行过程,假设n是严格二叉树的结点的个数,该算法的时间复杂度和最差情况空间复杂度都是O（n）。 相似文献
19.
在对传统的深度包过滤算法研究的基础上,提出了一种新的基于标示预处理的模式匹配算法,并予以实现。算法的时间复杂度小于O(n)(其中n为进行匹配的文本串长度)。 相似文献
20.
本文主要研究基因无方向的基因组重排的反转排序问题.本文算法基于断点图的概念,给出一个时间复杂性为O(maxb3(π),nb(π)),空间复杂性为O(n)的求解近似最优解的算法,其中n为基因组中基因个数,π=(π1,π2,...πn)表示n个基因的一种排列,b(π)表示排列π中的断点数.数据试验的结果表明,该近似算法可以求得较好的结果. 相似文献