压电驱动快速反射镜的自适应反演滑模控制

由压电驱动器驱动的快速反射镜(FSM)广泛应用于各种精密稳定跟踪系统,FSM的控制精度决定了系统的跟踪精度。但压电驱动器具有严重的迟滞非线性干扰,针对这一缺点,应用自适应径向基RBF神经网络对迟滞干扰进行非线性逼近,并在此基础上结合滑模控制和反演法,设计了自适应反演滑模(ABSM)控制器。仿真实验表明,相对于滑模控制器,ABSM控制器的最大跟踪误差和均方根误差为分别降低了57.26%和52.53%,提高了FSM的控制精度。     

基于径向基函数网络的区域物流能力投资结构优化

针对如何有效地提高区域物流能力,以推动区域经济增长的问题,构建了区域物流能力的投资结构优化模型.首先详细分析了优化区域产业投资结构能增强区域物流能力的原因,从产业结构的角度揭示了区域物流能力与产业投资分配之间复杂的非线性关系;然后采用径向基函数神经网络实现了它们之间的非线性映射,进而建立了有约束条件限制的非线性规划投资结构优化模型;最后以四川省2005年的产业投资实际数据为基础,采用改进遗传算法对该模型进行求解,获得了优化问题的近似最优解以及投资结构的优化方向.优化结果表明:建立的模型对产业投资结构的优化是合理、有效的,从而提供了一个能提高区域物流能力的实用且切实可行的新方法.     

基于提升小波与灰色神经网络的光纤陀螺振动误差建模

光纤陀螺在振动环境下的输出具有噪声大、漂移强的特性,必须建立合理的振动误差模型,以便使用精确的算法进行补偿,从而提高光纤陀螺的输出精度。文中首先使用Allan方差分析法分析了某型号的数字闭环光纤陀螺在振动环境下的输出信号,随后利用提升小波分离出了光纤陀螺误差模型中的白噪声及漂移误差,并提出了基于灰色理论和RBF神经网络的漂移误差建模方法。仿真结果表明,相较于传统的RBF神经网络模型,基于提升小波的灰色RBF神经网络的漂移误差建模方法能有效滤除白噪声,并将漂移误差模型的建模精度提高了一倍左右。该方法能够有效提高光纤陀螺在振动环境下的输出精度,对光纤陀螺在振动环境下的误差研究具有重要指导意义。     

高斯核正则化学习算法的泛化误差

对广义凸损失函数和变高斯核情形下正则化学习算法的泛化性能展开研究.其目标是给出学习算法泛化误差的一个较为满意上界.泛化误差可以利用正则误差和样本误差来测定.基于高斯核的特性,通过构构建一个径向基函数(简记为RBF)神经网络,给出了正则误差的上界估计,通过投影算子和再生高斯核希尔伯特空间的覆盖数给出样本误差的上界估计.所获结果表明,通过适当选取参数σ和λ,可以提高学习算法的泛化性能.     

A spintronic memristive circuit on the optimized RBF-MLP neural network

A radial basis function network (RBF) has excellent generalization ability and approximation accuracy when its parameters are set appropriately. However, when relying only on traditional methods, it is difficult to obtain optimal network parameters and construct a stable model as well. In view of this, a novel radial basis neural network (RBF-MLP) is proposed in this article. By connecting two networks to work cooperatively, the RBF's parameters can be adjusted adaptively by the structure of the multi-layer perceptron (MLP) to realize the effect of the backpropagation updating error. Furthermore, a genetic algorithm is used to optimize the network's hidden layer to confirm the optimal neurons (basis function) number automatically. In addition, a memristive circuit model is proposed to realize the neural network's operation based on the characteristics of spin memristors. It is verified that the network can adaptively construct a network model with outstanding robustness and can stably achieve 98.33% accuracy in the processing of the Modified National Institute of Standards and Technology (MNIST) dataset classification task. The experimental results show that the method has considerable application value.     

Research on Temperature Field Reconstruction Based on RBF Approximation with Polynomial Reproduction Considering the Refraction Effect of Sound Wave Paths

The temperature field distribution directly reflects the combustion condition in a furnace．In this paper, acoustic thermometry to reconstruct temperature distribution is investigated. A method based on radial basis function approximation with polynomial reproduction (RBF-PR) is proposed in order to improve the accuracy and stability of the method based on RBF approximation. In addition, the refraction effect of sound wave paths is considered in the process of reconstruction. The curved lines with refraction effect are numerically calculated by solving differential equations, which show that sonic waves curve towards the zones of higher temperature. The reconstructed performance is validated via numerical simulation using four temperature distribution models. Results and analysis show that the proposed method has much greater accuracy than the method based on RBF approximation, and when considering the effect of refraction, our method can reconstruct more excellent reconstruction performance than others, which do not take into account the refraction effect of sound wave paths.     

Random vibration of hysteretic systems under Poisson white noise excitations

Hysteresis widely exists in civil structures, and dissipates the mechanical energy of systems. Research on the random vibration of hysteretic systems, however,is still insufficient, particularly when the excitation is non-Gaussian. In this paper, the radial basis function(RBF) neural network(RBF-NN) method is adopted as a numerical method to investigate the random vibration of the Bouc-Wen hysteretic system under the Poisson white noise excitations. The solution to the reduced generalized Fokker...