舰载一维相控阵雷达波束电子稳定研究

提出了舰载一维相控阵雷达波束电子稳定的计算方法,弥补雷达波束随舰船摇摆而导致的指向偏移,取代机械稳定平台修正偏移量,满足空域覆盖.文中分析了基本的坐标变换,采用矢量旋转变换的方式研究了一维相控阵雷达的波束稳定,给出了波束稳定的计算公式,通过仿真验证了计算方法的有效性.该方法为工程实现提供理论支撑.     

舰船摇摆对舰载相控阵雷达发现目标概率的影响

文章分析了影响舰载相控阵雷达效能的诸多因素，分析了理想与实际天线波束单扫描周期发现目标的概率，对如何提高舰载相控阵雷达发现目标的概率给出了一些设计思想。     

舰船摇摆状态模拟系统

介绍了一种舰船摇摆状态模拟系统,给出了此舰船摇摆状态模拟系统的设计要点,以及此系统在雷达伺服系统中的应用效果。     

雷达伺服系统调试用虚拟摇摆平台的设计

应用多功能卡、数字-旋转变压器转换器及虚拟仪器等技术,设计了雷达伺服系统调试虚拟摇摆平台,用硬件电路及计算机软件来代替机电摇摆平台给雷达伺服系统提供等效正弦摇摆运动的实时角位置和角速度信号,具有更高的精度和性价比,为雷达伺服系统的调试带来很大的便利。     

舰载相控阵雷达跟踪波束的计算机控制

在将多功能相控阵雷达应用于舰载环境时，提出了一个重要的问题，就是在舰船摇摆环境下，相控阵雷达电子波束如何稳定而且精密地指出目标。本文提出一种实现电子跟踪波束稳定的计算机控制方法－动态补偿舰船摇摆运动与自适应卡尔曼滤波相结合，计算机仿真结果表明，该方法能够使舰载相控阵雷达电子跟踪波束稳定而且精密地指出机动目标，并易于实现。     

基于波束数字补偿方法提高导航雷达性能

针对船体摇摆使导航雷达波束偏移,影响雷达探测问题,提出了基于波束数字补偿技术,弥补雷达波束随舰船摇摆而导致方位指向偏移,消除纵横摇对方位角精度等雷达性能的影响。首先建立船体纵横摇数学模型,对目标回波特性分析,采用矢量变换、平面旋转变换结合立体几何关系得到水平波束方位角真值;同时分析了海面波束增益变化、海面指向波束宽度变化及低空目标方位补偿剩余;最后通过仿真验证了高海情及低海情下对波束的影响。该方法可以为雷达工程实现提供理论支撑。     

船摇扰动和雷达天线两轴稳定系统

本文分析了舰船摇摆对雷达天线角指向产生扰动的原因及雷达天线两轴稳定系统用速率陀螺构成稳定环路、隔离船摇干扰、提高雷达跟踪精度的方法。     

一种舰船摇摆下基于正弦空间的多波束覆盖范围计算方法

针对大地坐标系下雷达波束覆盖范围随着舰船摇摆不断变化这一现象，提出一种在正弦空间下计算该覆盖范围的方法。利用正弦空间中波束形状不变的特性，将大地坐标系映射到正弦空间中；然后进行等间隔取点计算；最后通过仿真验证了该方法的可行性，可为舰船摇摆下的波束调度提供理论依据。     

舰艇摇摆对雷达测向精度及工作方式的影响

当舰艇运动而发生摇摆时，雷达天线波束指向必然受到影响。仿真、分析了几种典型的天线座稳定平台隔离舰艇摇摆的能力，可根据系统要求，选择合适的天线稳定平台技术方案的技术指标。     

基于内模原理的舰载雷达稳定平台控制研究

舰载雷达稳定平台具有两个自由度,分别用于补偿舰体的纵横摇角度,同时还要克服摇摆运动导致的惯性力矩。此外,负载惯量随天线转动而变化。舰船的摇摆运动可以看作由若干正弦信号叠加而成。针对一类已知频率信息的摇摆运动,设计了基于内模原理的控制律。仿真结果表明,该控制律补偿舰体耦合扰动效果明显,系统稳态跟踪误差指数收敛至原点,且对摇摆运动的振幅、相位和负载转动惯量具有较强的鲁棒性。     

Adaptive coupling control for overhead crane systems

Due to the requirements of high positioning accuracy, small swing angle, short transportation time, and high safety, both motion and stabilization control for an overhead crane system becomes an interesting issue in the field of control technology development. Since the overhead crane system is subject to underactuation with respect to the load sway dynamics, it is very hard to manipulate the crane system in a desired manner, namely, gantry position tracking and sway angle stabilization. Hence, in this paper, a nonlinear control scheme incorporating parameter adaptive mechanism is devised to ensure the overall closed-loop system stability. By applying the designed controller, the position error will be driven to zero while the sway angle is rapidly damped to achieve swing stabilization. Stability proof of the overall system is given in terms of Lyapunov concept. To demonstrate the effectiveness of the proposed controller, results for both computer simulation and experiments are also shown.     

Tilting‐Sensitive Triboelectric Nanogenerators for Energy Harvesting from Unstable/Fluctuating Surfaces

The invention of triboelectric nanogenerators provides an opportunity to utilize previously wasted mechanical energy. The sway energy of ships that affects navigation and comfort on board has been considered negative in the past. Here, a tilting‐sensitive triboelectric nanogenerator (TS‐TENG) that can effectively harvest energy from unstable/fluctuating surfaces is demonstrated by using the sway energy of ships. The device adopts integrated blade structures on sliders, which make it sensitive to tilts and guarantee its power output. The response of the device to tilt agitations of different slopes and frequencies is systematically investigated. Rotational symmetry configuration is used to improve the motion stability of the device by excluding extra torque on the sliders. The peak power density and average power density of the TS‐TENG can reach 1.41 and 0.1 W m^?3, respectively, in low‐frequency and low‐amplitude fluctuating conditions. By the excellent performance of harvesting energy from unstable/fluctuating surfaces, the TS‐TENG is considered promising for powering various distributed sensor devices on the ship for smart ships.     

船载角跟踪系统船摇模拟器设计

舰船等航海设备在大海中航行会受到海洋气象环境的影响发生摇荡,其角跟踪性能会受船摇影响,可能难以跟踪目标,需要预先进行模拟分析以减小危害.角跟踪系统模拟船摇时,根据船摇信息,通过对无船摇影响的位置矢量进行欧拉角旋转,得到受船摇影响的位置矢量;利用矩阵变换解算出受船摇影响的轨道参数,进而推导出受船摇影响的和差支路信号功率及相位变化数据,实现船载角跟踪系统模拟器对船摇的模拟.试验表明,模拟船摇并采取相应隔离措施,角跟踪系统能够快速收敛.     

Antisway Tracking Control of Overhead Cranes With System Uncertainty and Actuator Nonlinearity Using an Adaptive Fuzzy Sliding-Mode Control

An adaptive fuzzy sliding-mode control (AFSMC) is presented for the robust antisway trajectory tracking of overhead cranes subject to both system uncertainty and actuator nonlinearity. First, a fuzzy sliding-mode control (FSMC) law is designed for the antisway trajectory tracking of the nominal plant. In association with a conventional trajectory tracking control law, this FSMC law guarantees asymptotic stability as well as improved transient response of the load sway dynamics while the trolley tracking error dynamics is rendered uniformly asymptotically stable. Second, a fuzzy uncertainty observer is designed to cope with system uncertainty as well as actuator nonlinearity present in an actual plant, and it is incorporated with the FSMC law for the development of the AFSMC law. In addition to stability analysis, the robust performance of the proposed AFSMC law is verified via numerical simulations and experiments.      

数字X光影像仪光机结构设计

设计了数字X光影像仪的光机结构.针对数字X光影像仪的特点和指标要求,确定了光机结构总体布局.介绍了数字X光影像仪的关键部分片盒、输片机构、激光扫描系统、荧光读取系统和消光系统的具体结构,并对输片传动机构进行了输片精度分析.检测结果表明,扫瞄轴晃动1.2″,输片精度0.015 mm.     

Simple rotary crane dynamics modeling and open-loop control for residual load sway suppression by only horizontal boom motion

To suppress two-dimensional load sway caused by the horizontal boom motion of a rotary crane, both horizontal and vertical boom motions are generally used. However, it would be more energy efficient and safer if a control scheme using only horizontal boom motion could be developed, eliminating the need for any boom vertical motion. In addition, if we can suppress load sway without the need to measure it, cost reduction of sensors can be achieved. Furthermore, the use of simple velocity trajectory patterns such as a trapezoidal velocity pattern and an S-curve acceleration/deceleration pattern, which are widely used in industrial automation systems, may provide cost-effective implementation of controllers. This paper presents a simple model of rotary crane dynamics that includes only significant centrifugal and Coriolis force terms. This simple model allows analytical solutions of the differential equations of the model to be derived. Thus, S-curve trajectory that considers residual vibration suppression without sensing it, using only horizontal boom motion, can be generated by solving only algebraic equations numerically. The effectiveness of the proposed method is demonstrated by numerical simulations and experimental results.     

Payload trajectory tracking of a 5-DOF tower crane with a varying-length hoist cable: A passivity-based adaptive control approach

This paper presents a passivity-based adaptive control method for a 5 degree-of-freedom (DOF) tower crane that guarantees robust payload trajectory tracking. The 5-DOF tower crane system considered in this work features three actuated degrees of freedom (including a varying-length hoist cable) and two unactuated degrees of freedom in the hoist cable sway. The proposed controller includes an adaptive feedforward-like control input that is used to ensure that the tower crane features an output strictly passive input–output mapping. The Passivity Theorem is invoked to guarantee closed-loop input–output stability for any output strictly passive negative feedback controller. A novel approach is developed to bound the time derivative of the system’s mass matrix, which is a critical aspect of the proof of passivity. Experimental tests are performed, which demonstrate the effectiveness of the control law on a small-scale three-dimensional tower crane.     

A Quiet Standing Index for Testing the Postural Sway of Healthy and Diabetic Adults Across a Range of Ages

A quiet standing index is developed for tracking the postural sway of healthy and diabetic adults over a range of ages. Several postural sway features are combined into a single composite feature C that increases with age a. Sway features are ranked based on the r ²-values of their linear regression models, and the composite feature is a weighted sum of selected sway features with optimal weighting coefficients determined using principal component analysis. A performance index based on both reliability and sensitivity is used to determine the optimal number of features. The features used to form C include power and distance metrics. The quiet standing index is a scalar that compares the composite feature C to a linear regression model f(a) using C ^'(a) = C/f(a). For a motionless subject, C ^' = 0, and when the composite feature exactly matches the healthy control (HC) model, C ^' = 1. Values of C ^' >> 1 represent excessive postural sway and may indicate impaired postural control. Diabetic neurologically intact subjects, nondiabetic peripheral neuropathy subjects (PN), and diabetic PN subjects (DPN) were evaluated. The quiet standing indexes of the PN and DPN groups showed statistically significant increases over the HC group. Changes in the quiet standing index over time may be useful in identifying people with impaired balance who may be at an increased risk of falling.     

Research on mobile phone swaying and receiving position in optical camera communication

Optical camera communication (OCC) is gaining increasing attention in researches. However, applying it to a real-world scenario may encounter many practical problems, such as the communication device may sway or there may be a position offset between the camera and the light source, which may distort the stripes and make the message unreceivable. To this end, we propose pilot-based stripe area estimation (P-SAE) decoding algorithm, and design a pixels rearrangement (PR) scheme and stripes separation logic decision method (SSLD) to improve the decoding performance under sway or receiving position offset. Finally, we build a practical OCC system and carry out experiments to verify the effectiveness of the decoding algorithm. Experimental results show that the lightweight decoding algorithm can resist the impact of smartphone sway and receiving position offset on decoding accuracy.     

星载光电跟踪系统跟踪精度分析

根据星载环境的特殊性及跟踪系统设计要求,对星载光电跟踪系统的跟踪精度做了较全面的定性分析和阐述。在理论分析的基础上,对工程实例的跟踪精度做了定量分析且提出了切实可行的提高系统跟踪精度的方法。最后试验证明提出的稳定跟踪技术满足了系统跟踪精度指标的要求。