Nonlinear disturbance observers for robotic continuum manipulators

Robots are an indispensable part of modern production lines. Usually working in designated areas, they are separated from human workers in order to avoid collisions. A safe collaborative work environment is enabled by so-called soft robots, which constitute a human-friendly alternative to classical rigid industrial robots. However, modeling soft robots proves difficult and results in a lack of accuracy for control tasks. In this contribution, a disturbance observer-based control is proposed in order to improve tracking behavior. In doing so, unknown model errors are considered as disturbances and estimated by an observer. This estimate is used to actively reject the perturbation. Different disturbance observers are designed and implemented for a soft quasi-continuum manipulator, amongst them two nonlinear disturbance observers and two extended state observers. The distinction in the versions of the same observation concept lies in the disturbance dynamics assumption, which is either considered static or as a damped double integrator. All implemented concepts combined with a PD control show superior performance compared to an existing benchmark concept based on PID-like control. Thanks to the modularity of this approach, disturbance observers can be further investigated in combination with other control strategies.     

高频雷达电台干扰抑制的稳健最小二乘方法

为对抗工作环境下的非平稳短波电台干扰,本文基于对偶极化的高频地波超视距雷达接收系统提出了新的稳健最小二乘抗干扰算法,改善高频雷达目标检测的性能.该方法基于凸空间最优化的思想,修正水平极化辅助天线接收数据,设定最大的环境误差范围,保证在最差误差环境下的最优干扰抑制性能.通过转换该凸最优的约束方程为简单的一维搜索,提出了最优加权系数的有效求解方法.实验数据处理结果表明了方法的有效性.     

滑翔制导炸弹变增益鲁棒控制器设计与仿真

针对滑翔制导炸弹,提出了一种变增益鲁棒控制器设计方法.通过将作战空域划分为几个小空域,并在其中一边界点对线性化后的系统,采用双回路鲁棒设计方法,设计满足系统性能和动态性能的鲁棒控制器.然后在各个边界点,采用插值方法将控制器内回路设计成与高度和速度相关的连续变增益控制回路,使内回路控制参数随着滑翔制导炸弹的飞行状态变化而变化,从而提高系统的性能.仿真结果表明,设计的控制器具有良好的时域响应性能,可以控制滑翔制导炸弹在大范围飞行过程中稳定,获得了满意的控制效果.     

基于稳健最小二乘的鲁棒波束形成

为解决Capon波束形成器在存在导向矢量失配时的性能急剧下降问题,提出了一种结合广义旁瓣对消器和稳健最小二乘的鲁棒波束形成算法.该算法利用广义旁瓣对消器原理将Capon波束形成器转化为最小二乘问题,然后在数据协方差矩阵误差的范数约束下将其转化为二阶锥规划问题,并利用高效内点法得到最优解.所提出的算法经推导证明属于对角加载类.仿真分析表明,该算法在导向矢量失配和快拍不足时仍具有较好的性能.     

Robust Design of Virtual Topology for WDM Networks under Bandwidth Demand Uncertainties

In this paper, a novel method is proposed to address the problem of designing virtual topology over wavelength division multiplexing （WDM） networks under bandwidth demand uncertainties. And a bandwidth demand model under uncertainties is presented. The optimization goal of virtual topology design is defined as minimizing the maximum value amongp percentiles of the bandwidth demand distribution on all Hght-paths. Correspondingly, we propose a heuristic algorithm called an improved decreasing multi-hop logical topology design algorithm （ID-MLTDA） that involves with a degree of uncertainties to design virtual topology. The proposed algorithm yields better performance than previous algorithms. Additionally, the simplicity and efficiency of the proposed algorithm can be in favor of the feasibility for topology design of large networks.     

一种新的基于角度和时差的稳健定位跟踪算法

针对无源定位必须实现快速和稳定无偏定位跟踪的要求,提出了一种新的双站基于角度和时差的稳健定位跟踪算法。该算法将扩维伪线性测量方程的观测误差矩阵协方差阵引入约束条件,通过对未知状态变量含二次约束的伪线性方程进行约束最小二乘(CLS)极小化处理,最终只需要对一对矩阵束进行广义特征分解即可获得目标状态的渐进无偏估计值。仿真结果表明,与扩展卡尔曼滤波（EKF）算法及最小二乘(LS)算法相比,本文所提算法定位跟踪性能更稳定,精度更高,估计误差可以接近克拉美罗限（CRLB）。在测量误差较大或者两个观测站测量误差不一致时优势更明显,实用性强。      

基于FDO非线性预测方法的翼伞航迹跟踪控制

在翼伞系统的状态空间模型的基础上,分析了翼伞的归航轨迹,给出翼伞轨迹跟踪控制问题的数学描述.针对翼伞归航飞行过程中,受到较大的外干扰及不确定性影响,提出基于模糊干扰观测器(FDO)的非线性预测控制策略,设计了翼伞归航系统航迹跟踪控制器.通过仿真试验,表明该飞控系统具有良好鲁棒特性和抗干扰特性.     

Robust loop shaping-fuzzy gain scheduling control of a servo-pneumatic system using particle swarm optimization approach

In this paper, a new technique called robust loop shaping-fuzzy gain scheduled control (RLS-FGS) is proposed to design an effective nonlinear controller for a long stroke pneumatic servo system. In our technique, a nonlinear dynamic model of a long stroke pneumatic servo plant is identified by the fuzzy identification method and is used as the plant for our design. The structure of local controllers is selected as PID control which is proven by many research works that this type of control has many advantages such as simple structure, well understanding, and high performance. The proposed technique uses particle swarm optimization (PSO) to find the optimal local controllers which maximize the average stability margin. In addition, performance weighting function which is normally difficult to obtain is automatically determined by PSO. By the proposed technique, the RLS-FGS controller can be designed, and the structure of local controllers is still not complicated. As seen in the simulation and experimental results, our proposed technique is better than the classical gain scheduled PID controller tuned by pole placement and the conventional fuzzy PID controller tuned by ISE method in terms of robust performance.     

基于扩展滑膜控制器的PMSM无速度传感器研究

本文设计了一种基于永磁同步电机（PMSM）直接转矩控制（DTC）的扩展滑膜观测器,通过测量定子电压与电流,获得电机的转速和转子位置。MATLAB仿真结果表明,扩展的滑膜观测器在空间矢量电压直接转矩控制（SVPWM-DTC）中,所得转速更接近实际转速。     

基于集员未知输入观测器的风力机桨距执行器故障诊断

风力机一般放置在恶劣的环境中,其桨距执行器极易出现故障。文中针对一类含有未知但有界干扰和噪声的风力机系统的桨距执行器故障问题,设计了集员未知输入观测器对桨距的执行器故障进行检测并分离。采用气动机理和现代辨识原理建立风力机系统模型,通过优化未知输入观测器设计对系统中的干扰解耦,基于中心对称多胞体估计不考虑故障时残差的区间包络,并将其作为残差估计的上下动态阈值,实现状态估计。在上述基础上提出了利用一组集员未知输入观测器进行故障诊断的策略。仿真结果表明,在实验过程中,文中所设计的集员未知输入观测器准确地诊断出了风力机桨距执行器的3阶和5阶线性系统在发生突变故障和缓慢时变故障的时间和位置,证明了所提故障诊断策略的有效性。