Energy-efficient control of nanosatellites during distributed region formation flying

In this paper, we present an energy-efficient method for distributed region formation flying of nanosatellites. The proposed framework consists of two concurrent sub-schemes that include estimation and formation. In the estimation sub-scheme, unlike the existing methods on satellite formation flying, that assume the availability of the reference orbital elements to all followers, here, a distributed estimator is developed so that the follower nanosatellites estimate the position of the leader in its orbital slot. In the formation sub-scheme, we consider a region formation strategy which is an efficient method in dealing with the formation of a large number of nanosatellites. We propose an optimal region following formation method based on the receding horizon control (RHC) using the estimated reference orbital elements. Subsequently, an algorithm is presented to solve the proposed energy-efficient formation flying method. Finally, the simulation result is presented that illustrates the purposed method improves the power consumption for each nanosatellite with respect to the existing non-optimal region formation flying controllers.     

Path‐Tracking Control of a Riderless Bicycle Via Road Preview and Speed Adaptation

In this study, a genetic‐fuzzy control system is used to control a riderless bicycle where control parameters can adapt to the speed change of the bicycle. The equations of motion are developed for a bicycle with constraints of rolling‐without‐slipping contact condition between the wheels and ground. This controller consists of two loops: the inner is a roll‐angle‐tracking controller which generates steering torque to control the roll angle while guaranteeing the stability, and the outer is a path‐tracking controller which generates the reference roll angle for the inner loop. The inner loop is a sliding‐mode controller (SMC) designed on the basis of a linear model obtained from a system identification process. By defining a stable sliding surface of error dynamics and an appropriate Lyapunov function, the bicycle can reach the roll‐angle reference in a finite time and follow that reference without chattering. The outer loop determines the proper reference roll‐angle by using a fuzzy‐logic controller (FLC) in which previewing and tracking errors are taken into consideration. The robustness of the proposed controller against speed change and external disturbances is verified by simulations.     

电子对抗训练中通信干扰效果评估方法研究

研究电子对抗训练中通信干扰的基本原理,分析通信干扰的基本方程和评估通信干扰效果的基本准则,利用这一准则对语音模拟通信干扰效果进行评估,并得出结果。     

未知环境下基于VFH＊的机器人避障

机器人避障问题一直是机器人应用中的热点和难点问题。为此采用了路径跟踪和VFH*相结合的方法实现机器人沿着预定路径前进中的避障问题。路径跟踪算法follow the carrot用来选取局部目标点。对于VFH*算法中存在的由于超声传感器的方向误差及对障碍物的扩展导致某些可行路径被忽略的情况进行了改进,在障碍物进行扩展时根据障碍物与机器人中心点的距离大小进行不同程度的扩展。另外,在障碍物比较稀的区域,VFH*算法对每个valley最多只选取三个候选方向,导致一些更好的方向丢失,根据valley的大小及机器人当前选定方向来增加一个新的候选方向。并用仿真验证了所做的改进是有效的。     

地形跟随/地形回避实时仿真系统的设计与实现

为了验证低空突防系统中的地形跟随/地形回避关键技术,设计了一套分布式实时仿真系统。该系统由主控机、地形跟随/地形回避(TF/TA)计算机和视景演示计算机组成。TF/TA计算机采用先进的嵌入式实时操作系统VxWorks进行TF/TA飞行轨迹规划,实时地形匹配,以及模拟雷达的实时数据生成。该系统可以验证算法,模拟飞机在空中飞行的实际效果,为TF/TA系统的试飞验证提供必要准备。     

基于CMAC的无人机紧密编队飞行控制研究

针对多无人机紧密编队飞行控制系统,提出一种基于小脑模型神经网络的编队飞行队形保持控制器。该控制器以飞行控制系统横向、纵向及垂直方向通道的动态误差作为小脑模型关节控制器（CMAC）的激励信号,并与常规的PID控制器相结合构成系统的复合控制。仿真结果表明：该控制器能够控制无人机编队,在定常运动和机动过程中都可以保持期望队形,且这种控制方法具有超调量较小,鲁棒性强,响应速度快,抗干扰能力强等优点。     

State predictive model following control system for linear time delays

In this paper, we propose a new state predictive model following control system （MFCS）. The considered system has linear time delays. With the MFCS method, we obtain a simple input control law. The bounded property of the internal states for the control is given and the utility of this control design is guaranteed. Finally, an example is given to illustrate the effectiveness of the proposed method.     

一种基于行为的移动机器人目标人跟踪控制方法

针对室内复杂环境,对于智能服务移动机器人,设计一个连续稳定的目标人跟踪算法是必要的.为此提出一种室内环境下基于行为的移动机器人对运动目标人进行跟踪的控制方法,该方法综合优先级裁决方法与模糊行为融合法选取移动机器人的控制行为,较好地解决跟踪过程中存在多种行为以及行为冲突问题,在完成运动避障的同时保持对运动目标的跟踪.对避...     

雷达抗干扰性能评估指标分析与测试平台设计

复杂电磁环境下雷达抗干扰性能外场实验通常具有复杂度高、设备代价高昂的问题。通过分析雷达电磁环境组成和相关评估指标,在综合一系列雷达对抗想定的基础上,提出了雷达对抗性能测试系统设计方案。该系统利用高速DSP和ARM终端显示控制灵活实现雷达干扰样式选择和参数设置。有效地解决了雷达状态信息采集、回波信号实时模拟以及战场环境想定的显控终端控制。研究了多种性能评估指标的具体测试方法,分析了影响干扰效果的关键性因素。结合具体雷达设备进行了雷达抗干扰半实物仿真实验,实验和数据处理结果证明了测试方法的有效性和可行性。该方法为解决有限设备条件下雷达抗干扰性能评估、雷达系统改进提供了参考依据。