结构谐振对闭环光纤陀螺振动性能的影响

振动性能是体现光纤陀螺环境适应性的一项重要指标。结构谐振是引起光纤陀螺振动误差的主要因素之一。在描述了光纤传感环圈骨架谐振对陀螺振动性能影响的试验现象的基础上,通过环圈骨架的有限元分析,以及光纤陀螺振动误差模型的推导,得出了环圈骨架谐振频率与陀螺振动输出零位漂移最大点的频率相吻合的结论。针对环圈骨架的薄弱环节进行改进设计及实验验证,结果表明消除结构谐振后的陀螺在0～2000Hz之间振动,输出不再发生明显漂移,振动过程中陀螺的零偏变化不超过0.2(o)/h。     

尾纤长度不对称导致的光纤陀螺振动误差分析

如何提高光纤陀螺在振动环境下的精度是光纤陀螺工程化过程中必须考虑的问题。当前,对于降低光纤陀螺振动误差的方法主要集中在改善光纤陀螺的机械结构和固定光纤环上。然而,Y波导与光纤环的尾纤长度不对称也是引起光纤陀螺振动误差的一个重要原因。首先根据弹光效应从理论上阐述了由振动所引起非互易相移的原理,进而分析证明了振动条件下左右两侧的波导尾纤与光纤环的尾纤长度之和不相等,即尾纤长度不对称是导致振动条件下非互易相移产生的一个重要原因。在此基础上推导出了振动条件下光纤陀螺两侧尾纤长度和之差与陀螺输出误差的理论关系式,并通过Matlab仿真了两侧尾纤长度和之差与陀螺输出漂移的关系曲线。     

基于固态振动陀螺的短期偏置稳定性研究

该文研究了固态振动陀螺的短期稳定性.从固态振动陀螺的动力学方程入手,讨论了影响固态振动陀螺短期偏置稳定性的因素,计算结果显示,暂态解误差是影响陀螺短期偏置稳定性的主要因素,针对暂态解的特点采用低通滤波器进行滤波.仿真结果表明,低通滤波器能有效抑制输出值中的误差信号,并对压电振动陀螺进行滤波实验,实验结果同仿真结果吻合很好,由此可得出该模型的正确性和滤波方案的可行性.     

舰载光电跟踪系统跟踪误差源分析

根据目标信息在舰载条件下各个环节中的传递过程,分析光电跟踪系统跟踪性能各种影响因素,给出了主要的误差源.在考虑不同误差属性的基础上,给出了脱靶量测量误差在伺服控制系统中的传递方法.同时,给出伺服系统动态滞后误差、扰动力矩产生的跟踪误差,以及由于舰船运动对跟踪性能的影响.     

光纤陀螺的角加速度误差分析与实验研究

角加速度误差是光纤陀螺的一项动态误差,该误差会引起光纤陀螺捷联惯导系统的姿态误差,制约捷联惯性导航系统在高动态应用条件下的精度。针对这种情况,在光纤陀螺闭环控制模型的基础上建立了闭环光纤陀螺的角加速度误差模型,并分析了影响角加速度误差的几项重要因素,包括控制回路总增益及控制周期等;随后给出了减小该误差的方法。基于等效输入原理,通过在反馈阶梯波上叠加斜坡信号,分别在不同条件下对闭环光纤陀螺的角加速度误差进行了测试实验。实验结果表明,不同角加速度和控制回路总增益条件下的角加速度误差测试值与理论计算值基本一致,验证了该误差模型的正确性。     

红外捕获跟踪设备闭环注入式仿真试验的理论研究

提出了一种采用数字图像注入式方法进行红外捕获跟踪设备闭环仿真和性能测试。在仿真测试时,红外捕获跟踪设备的传感器被图像仿真机和图像注入设备取代,图像生成及脱靶量计算环节的延迟和误差使跟踪伺服系统的性能与实际工作情况不一致,影响了仿真试验结果精度和置信度。从设备的实际情况和注入式仿真试验下伺服控制系统的等效性考虑,利用某型实际设备的伺服控制系统模型,仿真分析了在不同脱靶量延时和脱靶量误差下,系统跟踪迎头飞行目标时的稳定性和动态跟踪精度的变化,获得了设备允许的脱靶量大小和图像仿真最大延时。结果表明:脱靶量输出延迟不大于2帧时设备能稳定跟踪目标,为保持两种情况下伺服系统性能的一致,注入式试验时脱靶量随机误差最大为25″,图像仿真的最大延迟时间为19 ms。研究成果为红外捕获跟踪设备的闭环注入式仿真试验的可行性提供了理论支撑。     

提高机械抖动激光陀螺抗振性能

通过提升谐振腔抗光路变形能力,可以有效提高机械抖动激光陀螺的抗振动性能。对机械抖动激光陀螺振动中光路扭偏的产生机理进行了理论计算与仿真分析,分析结果表明,抖动切向惯性力和振动冲击惯性力是引起振动中光路扭偏的主要原因。通过振动中光路扭偏对振动性能影响的理论分析指出,减小振动附加上去的朗缪尔零偏,提高陀螺抗振性能的两大有效措施是减小工作电流和提高光路抗失谐能力。通过物理试验验证了振动中光路扭偏机理仿真分析的正确性。不同工作电流的振动对比试验表明,降低工作电流可显著提高陀螺的振动性能,这对于机抖激光陀螺振动特性的提升具有重要指导意义和工程实用价值。     

惯性稳定平台中的加速度反馈控制技术

陀螺稳定是惯性稳定中的常见装置,由它仅仅构成一个简单的单速度稳定环。控制带宽是影响陀螺稳定的惯性控制系统的一个重要因素。高的控制带宽很难获取,主要是因为系统的非线性影响,比如机械谐振。将一种基于加速度反馈的多环控制结构引入速度控制系统中,提高稳定性能。采用两只线性加速度计测量角速度信号,而不是利用位置和速度信号计算得到。利用 Lyapunov 函数分析了多级稳定回路稳定,以及对摩擦、扰动抑制能力的效果。多级稳定控制环路的误差抑制能力是陀螺反馈系统的能力以及加速度反馈之积。实验验证了理论分析的正确性:相比经典的陀螺稳定系统,扰动抑制能力有较大的改善。     

基于传感器融合预测的改进跟踪前馈控制方法研究

针对光电跟踪系统中CCD相机反馈帧率较低，延迟较大导致跟踪高速目标能力差、响应能力差的问题，提出一种基于传感器融合预测的改进跟踪前馈控制方法。为减小融合获得目标高阶运动状态噪声大的问题，提出一种基于微分跟踪的传感器融合策略；针对图像反馈延迟问题，提出一种降阶匀加速Kalman模型，根据融合获得的运动学信息，结合Kalman滤波进行预测跟踪，补偿脱靶量的时间延迟，得到近似真实的目标位置和速度、加速度信息；针对低频输入信号引入闭环扰动问题，提出一种快速数据扩展方法，实现低频信号到高频信号的扩展；根据传感器融合预测结果，设计跟踪前馈控制器，提高系统的响应速度。仿真结果和实验结果均表明该前馈方法能够对CCD反馈延迟导致的跟踪误差进行补偿。实验结果表明：该方法能够大幅提高系统对高速目标的跟踪性能，在目标运动状态相同条件下，相比补偿前跟踪误差减小约83.67%。     

谐振式集成光学陀螺三角波调制误差分析

在基于模拟三角波相位调制技术的谐振式集成光学陀螺(IORG)调制方案中,调制三角波参数受外界环境等变化而产生波动是陀螺输出误差的主要来源之一。给出了调制三角波参数与陀螺输出的特性关系;分析了调制三角波参数波动与陀螺标度因数的变化关系;仿真计算了调制三角波参数波动与陀螺输出非线性度的关系。搭建了IORG实验系统,通过采用精密高频波形产生器产生调制三角波,得到了1h零偏稳定性为0.69(°)/s,±500(°)/s动态范围内非线性度为0.96%的陀螺输出。实验验证了理论分析计算方法的正确性以及采用模拟三角波调制方法改善集成光学陀螺检测精度的可行性。     

Fuzzy Feedback Linearization Control for MIMO Nonlinear System and Its Application to Full-Vehicle Suspension System

The paper presents a novel fuzzy feedback linearization control of nonlinear multi-input multi-output (MIMO) systems for the tracking and almost disturbance decoupling (ADD) performances based on the fuzzy logic control (FLC). The main contribution of this study is to construct a controller, under appropriate conditions, such that the resulting closed-loop system is valid for any initial condition and bounded tracking signal with the following characteristics: input-to-state stability with respect to disturbance inputs and almost disturbance decoupling. The feedback linearization control guarantees the almost disturbance decoupling performance and the uniform ultimate bounded stability of the tracking error system. As soon as the tracking errors are driven to touch the global final attractor with the desired radius, the fuzzy logic control immediately is applied via a human expert’s knowledge to improve the convergence rate. One example, which cannot be solved by the previous paper on the almost disturbance decoupling problem, is proposed in this paper to exploit the fact that the tracking and the almost disturbance decoupling performances are easily achieved by the proposed approach. In order to demonstrate the applicability, this paper has investigated a full-vehicle suspension system.     

Distributed power allocation algorithm in wireless networks under SNR constraints

In this work, the distributed power allocation problem in wireless networks is studied under signal-to-noise ratio (SNR) constraints. The sources of uncertainty are assumed to come from the quantization process and measurement noise in the feedback system. The power allocation is formulated as a reference tracking problem of a pre-defined signal to noise-interference ratio. First, the synthesis problem with SNR constraints is studied as a 2-norm minimization process, which is equivalent to a linear-quadratic-regulator (LQR) problem. The solution of the associated Riccati equation in the LQR formulation is completely characterized, resulting in a feedback law with a recurrent structure. This control law is re-written in a transfer function format, where a simple control strategy is obtained which is dependant on the round-trip delay in the feedback system. In addition, the corresponding 2-norm closed-loop performance is also studied. Thus, the selection of the weight in the LQR problem establishes a compromise between robustness to quantization errors and measurement noise, and tracking performance. A comprehensive simulation evaluation validates the analytical derivations described in the paper.     

Stabilization for Stochastic Nonlinear Differential Inclusion Systems with Time Delay

In this paper, the stabilization problem for stochastic non-linear differential inclusion systems with time delay is discussed. First, the definition of the exponential stability in mean square for stochastic differential inclusion is presented. Second, under the framework of the convex hull Lyapunov function, a continuous feedback law is designed to make the closed-loop system exponentially stable in mean square. Finally, two numerical examples are presented to demonstrate the effectiveness of the proposed controller for the stabilization problem discussed in this paper.     

Time delay control with state feedback for azimuth motion of thefrictionless positioning device

A time delay controller with state feedback is proposed for azimuth motion control of the frictionless positioning device which is subject to the variations of inertia in the presence of measurement noise. The time delay controller, which is combined with a low-pass filter to attenuate the effect of measurement noise, ensures the asymptotic stability of the closed-loop system. It is found that the low-pass filter tends to increase the robustness in the design of the time delay controller, as well as the gain and phase margins of the closed-loop system. Numerical and experimental results support that the proposed controller guarantees a good tracking performance, irrespective of the variation of inertia and the presence of measurement noise     

一种新的连续值反馈闭环拥塞控制方案的设计及性能分析

本文提出并分析了一种连续值反馈闭环拥塞控制方案。证明了它的无振荡稳定性,推导出使得系统性能达到最佳的参数设置。所谓最佳是指：系统达到稳定的速度很快;稳态下,系统的带宽利用率最大,并且延迟最小。文中的仿真结果表明,该方案在各种情况下运行正常,且性能优于其它的一些连续反馈控制方案。     

Networked Predictive Control of Systems With Random Network Delays in Both Forward and Feedback Channels

The design problem of networked control systems (NCS) with constant and random network delay in the forward and feedback channels, respectively, is considered in this paper. A novel networked predictive control (NPC) scheme is proposed to overcome the effects of network delay and data dropout. Stability criteria of closed-loop NPC systems are presented. The necessary and sufficient conditions for the stability of closed-loop NCS with constant time delay are given. Furthermore, it is shown that a closed-loop NPC system with bounded random network delay is stable if its corresponding switched system is stable. Both simulation study and practical experiments show the effectiveness of the control scheme     

Analysis of the feedback envelope tracking linear class E power amplifier

Feedback envelope tracking amplifier is one technology to realize linear amplification for nonlinear class E power amplifier. In this paper, the basic architecture and frequency response of the feedback envelope tracking amplifier are analyzed in detail. And the analysis shows that the feedback envelope tracking loop can be implemented to satisfy the system’s specifications of linearity and stability, if the bandwidth and the other design parameters are properly selected. The limited bandwidth and different time delay between the envelope path and the phase path can cause intermodulation distortions which deteriorate the linearity of the feedback envelope tracking amplifier, the model for the intermodulation distortions of the feedback envelope tracking class E power amplifier is analyzed compared to the envelope elimination and restoration transmitter. In order to evaluate the broadband performance of the feedback envelope tracking class E power amplifier, the error vector magnitude (EVM) specification is also analyzed, and the simulation results on EVM for WCDMA signal is given.     

Discrete sliding-mode control of a PWM inverter for sinusoidaloutput waveform synthesis with optimal sliding curve

This paper presents a discrete sliding-mode control scheme with feedforward compensation for the closed-loop regulation of the pulse-width modulated (PWM) inverter used in an uninterruptible power supply (UPS). The proposed feedforward controller can effectively improve the tracking performance of the PWM inverter. In designing the sliding-mode controller, we have taken load disturbance into consideration to enhance the robustness of the PWM inverter. Moreover, the upper bound of the load disturbance under which the sliding condition can be maintained has also been derived. The sliding curve of the sliding-mode controller is designed such that the behavior of the controlled PWM inverter is optimal subject to the selected cost function. Due to the coordinate transformation proposed in this paper, only the output voltage needs to be measured as feedback for the purpose of closed-loop regulation. Simulation and experimental results are given to show the effectiveness of the proposed control scheme     

闭环光纤陀螺方波调制失真的影响与消除

数字闭环光纤陀螺仪测量角速度时,采用方波调制引起的各种失真会对输出结果产生影响。基于傅里叶级数建立包含失真噪声的闭环光纤陀螺方波调制、解调信号模型,对各种调制失真引起的输出误差进行了仿真分析,并提出一种双极型归零脉冲方波解调方法,用于消除方波调制闭环光纤陀螺仪的输出信号误差。仿真结果表明:采用常规方波解调时,调制信号的相位失真、方波脉宽失真、谐波失真以及梳状噪声脉冲对光纤陀螺仪输出有很大影响,测量角速度相对误差可达1%量级。采用双极型归零脉冲方波解调时,上述调制失真的影响都得到有效的减小,陀螺仪测量角速度相对误差只有0.1%量级,降低了一个数量级,说明文中提出的双极型归零脉冲方波解调方法对提高闭环陀螺的测量精度和稳定性有重要意义。     

Random vibration test control of inverter-fed electrodynamic shaker

The random vibration control of an inverter-fed electrodynamic shaker is presented in this paper. First, the dynamic model of the shaker is found and a current-controlled pulsewidth modulation inverter is designed and implemented. The feedback controller is augmented with a command feedforward controller and a disturbance feedforward controller to let the armature exciting current have low harmonic content and possess excellent waveform tracking performance. Then, an acceleration controller and its random vibration command are arranged. In the proposed acceleration control scheme, a command feedforward controller and a robust disturbance feedforward controller are also employed to let the shaker have close random acceleration command waveform tracking control performance, and the performance be insensitive to the system parameter variations. It follows that the acceleration control with desired frequency response in a vibration test could be achieved through properly setting the command signal. The effectiveness of the proposed control scheme is verified by simulation and measured results