The steered covariance matrix(STCM) and its inverse matrix should be calculated in each beam for steered minimum variance(STMV) . The inverse matrix needs complex computation and restricts its application in engineeri...The steered covariance matrix(STCM) and its inverse matrix should be calculated in each beam for steered minimum variance(STMV) . The inverse matrix needs complex computation and restricts its application in engineering. Combining the integration character of one-phase regressive filter with the iterative formula of inverse matrix,an STMV iterative algorithm is proposed. The computational cost of the iterative algorithm is reduced approximately to be 2/M times of the original one when there are M sensors,and is more advantaged for the realization of the algorithm in real time. Simulation results show that the STMV iterative algorithm can preserve the characters of STMV on high azimuth resolution and weak target detection while the computational cost reduced sharply. The analysis on sea trial data proves that the proposed algorithm can estimate each target's azimuth even when the source powers differ in large scales or their bearings are very approximate.展开更多
In this paper, the application of modified genetic algorithms (MGA) in the optimization of the ARX Model-based observer of the Pneumatic Artificial Muscle (PAM) manipulator is investigated. The new MGA algorithm is pr...In this paper, the application of modified genetic algorithms (MGA) in the optimization of the ARX Model-based observer of the Pneumatic Artificial Muscle (PAM) manipulator is investigated. The new MGA algorithm is proposed from the genetic algorithm with important additional strategies, and consequently yields a faster convergence and a more accurate search. Firstly, MGA-based identification method is used to identify the parameters of the nonlinear PAM manipulator described by an ARX model in the presence of white noise and this result will be validated by MGA and compared with the simple genetic algorithm (GA) and LMS (Least mean-squares) method. Secondly, the intrinsic features of the hysteresis as well as other nonlinear disturbances existing intuitively in the PAM system are estimated online by a Modified Recursive Least Square (MRLS) method in identification experiment. Finally, a highly efficient self-tuning control algorithm Minimum Variance Control (MVC) is taken for tracking the joint angle position trajectory of this PAM manipulator. Experiment results are included to demonstrate the excellent performance of the MGA algorithm in the NARX model-based MVC control system of the PAM system. These results can be applied to model, identify and control other highly nonlinear systems as well.展开更多
为了降低波束的旁瓣和主瓣宽度并提高抗干扰能力,本文提出了一种基于相关函数的低维度宽带波束形成算法。首先,对宽带信号进行FFT变换以将其转化为多个子带的窄带信号;其次,基于最小方差(MV)准则并利用相关函数将子带信号的干扰-噪声协...为了降低波束的旁瓣和主瓣宽度并提高抗干扰能力,本文提出了一种基于相关函数的低维度宽带波束形成算法。首先,对宽带信号进行FFT变换以将其转化为多个子带的窄带信号;其次,基于最小方差(MV)准则并利用相关函数将子带信号的干扰-噪声协方差矩阵重构为相关矩阵,以达到有效抑制噪声和干扰的目的;然后,利用降维算法以降低相关矩阵的复杂度,并利用拉格朗日乘数法来求解最优权矢量;最后,利用切比雪夫滤波器对最优权矢量进行静态加权调整,以期获得更高的阵列增益和更低的旁瓣电平。仿真结果表明:该算法的计算复杂度较小,主瓣宽度变窄1度左右,最佳输出信干噪比提高了约-1.3 d B,同时旁瓣幅度有效降低。展开更多
对同步发电机励磁系统性能评价一般通过阶跃响应方法,但该方法无法在线进行,为此提出了最小方差控制基准的性能评估方法。对系统设计最小方差控制器并作为系统控制性能上限,与系统实际性能进行比较而得到性能指标,并对该方法进行系统滤...对同步发电机励磁系统性能评价一般通过阶跃响应方法,但该方法无法在线进行,为此提出了最小方差控制基准的性能评估方法。对系统设计最小方差控制器并作为系统控制性能上限,与系统实际性能进行比较而得到性能指标,并对该方法进行系统滤波和相关性分析FCOR(Filtering and Correlation Analysis)算法的改进,避免了Diophantine方程的展开运算。分析表明该评估方法只需利用同步发电机输出端电压数据,结合系统时滞d就可以得到励磁系统的性能指标。仿真结果表明该方法简化了计算过程,能够及时准确地在线评估励磁系统的控制性能。展开更多
文摘The steered covariance matrix(STCM) and its inverse matrix should be calculated in each beam for steered minimum variance(STMV) . The inverse matrix needs complex computation and restricts its application in engineering. Combining the integration character of one-phase regressive filter with the iterative formula of inverse matrix,an STMV iterative algorithm is proposed. The computational cost of the iterative algorithm is reduced approximately to be 2/M times of the original one when there are M sensors,and is more advantaged for the realization of the algorithm in real time. Simulation results show that the STMV iterative algorithm can preserve the characters of STMV on high azimuth resolution and weak target detection while the computational cost reduced sharply. The analysis on sea trial data proves that the proposed algorithm can estimate each target's azimuth even when the source powers differ in large scales or their bearings are very approximate.
文摘In this paper, the application of modified genetic algorithms (MGA) in the optimization of the ARX Model-based observer of the Pneumatic Artificial Muscle (PAM) manipulator is investigated. The new MGA algorithm is proposed from the genetic algorithm with important additional strategies, and consequently yields a faster convergence and a more accurate search. Firstly, MGA-based identification method is used to identify the parameters of the nonlinear PAM manipulator described by an ARX model in the presence of white noise and this result will be validated by MGA and compared with the simple genetic algorithm (GA) and LMS (Least mean-squares) method. Secondly, the intrinsic features of the hysteresis as well as other nonlinear disturbances existing intuitively in the PAM system are estimated online by a Modified Recursive Least Square (MRLS) method in identification experiment. Finally, a highly efficient self-tuning control algorithm Minimum Variance Control (MVC) is taken for tracking the joint angle position trajectory of this PAM manipulator. Experiment results are included to demonstrate the excellent performance of the MGA algorithm in the NARX model-based MVC control system of the PAM system. These results can be applied to model, identify and control other highly nonlinear systems as well.
文摘为了降低波束的旁瓣和主瓣宽度并提高抗干扰能力,本文提出了一种基于相关函数的低维度宽带波束形成算法。首先,对宽带信号进行FFT变换以将其转化为多个子带的窄带信号;其次,基于最小方差(MV)准则并利用相关函数将子带信号的干扰-噪声协方差矩阵重构为相关矩阵,以达到有效抑制噪声和干扰的目的;然后,利用降维算法以降低相关矩阵的复杂度,并利用拉格朗日乘数法来求解最优权矢量;最后,利用切比雪夫滤波器对最优权矢量进行静态加权调整,以期获得更高的阵列增益和更低的旁瓣电平。仿真结果表明:该算法的计算复杂度较小,主瓣宽度变窄1度左右,最佳输出信干噪比提高了约-1.3 d B,同时旁瓣幅度有效降低。
文摘对同步发电机励磁系统性能评价一般通过阶跃响应方法,但该方法无法在线进行,为此提出了最小方差控制基准的性能评估方法。对系统设计最小方差控制器并作为系统控制性能上限,与系统实际性能进行比较而得到性能指标,并对该方法进行系统滤波和相关性分析FCOR(Filtering and Correlation Analysis)算法的改进,避免了Diophantine方程的展开运算。分析表明该评估方法只需利用同步发电机输出端电压数据,结合系统时滞d就可以得到励磁系统的性能指标。仿真结果表明该方法简化了计算过程,能够及时准确地在线评估励磁系统的控制性能。
