Precision Stabilization Systems

This paper discusses the relationships that must be considered in analyzing the design and performance of typical precision stabilization systems. In particular, the disturbance inputs that are due to kinematic and geometrical coupling are examined in depth by considering systems implemented with either a conventional two-axis gimbal or a traditional half-angle mirror assembly. The disturbance coupling that is associated with the gimbal drive actuators and the effect of structural compliance on the stabilization control loops are also discussed in detail. Other aspects of stabilization system design that are considered include the potential improvements in performance that can be achieved by using appropriate multiaxis gimbal configurations and by utilizing the angular pointing characterisitics of beam expansion telescopes.     

控制力矩陀螺磁轴承-框架动力学耦合特性仿真研究简

框架角速率精度决定着控制力矩陀螺输出的姿态控制力矩精度,前者的精度由框架伺服电机力矩精度和框架转动惯量决定.磁悬浮控制力矩陀螺框架转动和陀螺转子的微小扭摆运动间存在动力学耦合,其框架表现出比标称值大的等效转动惯量.在柔性结构框架动力学模型和磁轴承刚度-阻尼模型基础上,研究磁轴承-框架动力学特性,推导出框架等效转动惯量和磁轴承控制参数之间的关系式,表明调整磁轴承控制参数能增大框架等效转动惯量,提高框架角速率精度.根据闭环系统稳定性和轴承承载力,确定了磁轴承控制参数取值范围,并给出了框架等效转动惯量的调节范围.通过对某小型磁悬浮控制力矩陀螺框架角速率控制系统的Simulink仿真,证明了控制力矩精度可以提高5倍,验证了模型的准确性.     

Advanced Development of ESG Strapdown Navigation Systems

The fundamental problem of inertial navigation, double integration of acceleration to obtain position, is defined and discussed. Mechanizations of both space-stable and local-vertical platform systems are exhibited. The synthesis problem for an electrically suspended gyro (ESG) strapdown system is defined and discussed: readout, readout errors due to vehicle motion, synchronization of readout with system computer, alignment, correction and calibration for mass unbalance drift, and digital mechanization. Alignment, calibration, and acceleration measurement are also discussed. Sources of error involved in the electronic gimbaling including those peculiar to strapdown configuration are discussed and compared to mechanically gimbaled systems. Advanced developments required in the component and systems areas are listed, and it is shown that such development will lead to reduced complexity, higher accuracy, and increased reliability and utility for inertial systems.     

一种补偿惯性平台基座不水平的转位算法

针对静基座平台系统调平进行了研究, 详细分析了四轴平台系统台体坐标 系、框架坐标系及基座坐标系间的空间关系,推导出了台体不同位置调平时框架角间的 关系,设计了补偿平台基座不水平的转位方法。当基座不水平角度较大时,通过该方法 可将平台直接转位至调平角度附近,不需经过粗调平便可直接进入精调平,从而可以使 平台系统的工作过程得到简化,对于提高平台的任意位置转位及自标定、自瞄准效率有 重要意义。     

基于ESO的DGVSCMG双框架伺服系统不匹配扰动抑制

针对双框架变速率控制力矩陀螺（DGVSCMG）两种工作模式下内、外框架系统存在的不匹配干扰抑制问题,提出一种基于扩张状态观测器与状态反馈的扰动抑制方法。在对飞轮工作模式和陀螺工作模式下内、外框架系统的干扰进行建模和分析的基础上,针对其不匹配干扰设计了扩张状态观测器,通过坐标变换减小框架系统扰动对不匹配通道的影响,并结合状态反馈控制设计了复合控制器,同时对全局系统稳定性进行了分析。对框架系统进行的仿真结果验证了所提复合控制方法的有效性。实验结果表明,所提出的控制方法能有效减小耦合力矩对内外框架角速率带来的影响,在飞轮模式下使得内外框架的角速率跳动量分别降低了85%和78%,且在陀螺模式下使外框架角速率跳动量降低了75%。     

基于扩张状态观测器的DGMSCMG框架伺服系统振动抑制方法

针对带有谐波减速器的双框架磁悬浮控制力矩陀螺(DGMSCMG)框架系统存在较低频率谐振点的问题,提出了一种基于扩张状态观测器(ESO)振动抑制的控制方法。在谐波减速器的输入端和输出端分别设计三阶扩张状态观测器,通过电机及负载端的角位置信号不但能够估计电机和负载的角速率,而且可以比较准确地估计到扭转刚度的非线性变化及外部扰动力矩引起的综合扰动,通过反馈及前馈补偿对综合扰动进行抑制。设计的基于扩张状态观测器的控制器抑制了框架伺服系统的振动、提高了框架的速率输出精度。仿真及实验结果表明了该控制算法是有效的并具有较强的鲁棒性。     

铝基复合材料在平台环架的应用研究

惯性平台环架对零件的刚度、强度的要求很高,传统铝合金材料已经很难满 足新型平台的要求。对铝基复合材料早期性能和改良后的性能进行了研究,通过仿真分析 及力学试验,验证了铝基复合材料通过二次变形加工的方法,有效提高了强度和延伸率, 应用复合材料后,在大过载情况下能够有效抵抗变形,从而提高平台系统精度。     

双框架MSCMG框架伺服系统的动力学解耦及扰动补偿

双框架磁悬浮控制力矩陀螺(MSCMG)框架伺服系统是一个多变量、强耦合、非线性的复杂系统,针对耦合力矩对框架系统速率伺服性能的影响,以及框架系统动力学解耦之后存在残余耦合、卫星运动引起的牵连力矩和非线性摩擦的问题,提出了微分几何法与扩张状态观测器(ESO)相结合的高精度控制方法,在线性化解耦的基础上对残余耦合、牵连力矩及非线性摩擦进行观测补偿以提高框架伺服系统解耦及速率跟踪性能。仿真结果表明、由耦合力矩引起的内、外框架速率波动最大值分别从0.18(°)/s和0.12(°)/s减小到5×10^-3(°)/s和4×10^-3(°)/s,内、外框架正弦角速度跟踪误差分别从0.18(°)/s和0.19(°)/s减小到0.005(°)/s和0.004(°)/s。所提出的方法实现了框架伺服系统的动力学解耦以及非线性摩擦和牵连力矩的补偿,提高了框架系统的解耦性能和速率伺服精度。     

Leveling of Analytic Platforms

Use of an analytic platform or strapdown system requires that the system em be initially leveled just as a conventional multigimbaled platform must be leveled. The process of leveling involves the determination of the orientation between the local vertical and an instrumented reference nce frame. With a conventional platform it is quite common to use a pair of servo loops to precess the inner gimbal until gravity signals are nulled on two orthogonally mounted accelerometers. The input axes of these two accelerometers thus define the horizontal plane and the platform is said to be leveled. A strapdown system, however, lacks the physical entity of the inner gimbal and consequently cannot be physically precessed into verticality. The method of leveling is nonetheless analogous if we consider the computational reference frame of the analytic platform to be the "alter ego" or counterpart of a physical inner gimbal. In general, strapdown leveling techniques can be divided into two categories: closed-loop leveling and open-loop leveling. These two techniques are quantitatively developed and discussed in this paper.     

采用框架角受限控制力矩陀螺的航天器姿态机动控制

以框架角受限的金字塔构型控制力矩陀螺(CMG)为执行机构,研究了航天器欧拉姿态机动控制问题.考虑控制力矩及航天器角速度约束等因素,对已有的姿态机动控制律进行了改进,使其能实现绕欧拉轴的大角度姿态机动.同时考虑力矩陀螺框架角受限情况,通过适当加入空转指令对框架角进行重构,设计了复合控制形式的控制力矩陀螺操纵律,并通过过渡...     

滚转弹两框架导引头的前馈补偿技术

针对弹体滚转情况下两框架平台式导引头的伺服控制问题,基于导引头运动学和动力学,建立了导引头稳定回路模型。结合弹体滚转条件下的导引头输入指令和输出视线角速率关系,构建了视线闭环回路。针对偏航、俯仰通道间的解耦控制问题,推导出解耦条件,要求两通道由失调角到光轴转动角速度的传递函数相同。仿真分析了该模型在视线角输入以及弹体姿态扰动输入时,弹体滚转对导引头跟踪精度产生的影响,并由此提出了滚转角速度前馈补偿控制方案。结果表明,采用结合滚转角前馈补偿控制的两框架平台式导引头方案可以满足滚转弹的制导精度要求。     

某型转台内框热力耦合分析

转台内框是决定转台测试精度的重要部件。本文采用有限元方法,计算了内框在同时受到负载热和重力耦合作用下的应力和变形。结果表明,内框在热力耦合的影响下产生的变形量,比单独受热和受力线性叠加后产生的形变量要大。热力耦合分析综合考虑了各误差源对转台精度的影响,可用于指导结构优化设计。     

基于实时预测轨迹修正的共轴跟踪观测方法

针对光电设备跟踪观测轨迹可预测目标，提出并实现了基于实时预测轨迹修正的新型跟踪算法。从电视观测信息中实时解算出轨迹偏差的位置分量与速度分量并修正预测轨迹，引导仪器运动。应用该方法，在被观测目标电视探测不理想时有效提高了跟踪可靠性，降低了光电跟踪设备对电视探测能力的苛刻要求。即使电视探测短时出现困难，也能保证一定精度。本文给出了实时轨迹修正跟踪方法的构成原理与试验结果，并与一般电视跟踪方法进行了对比。     

Avionics for the Small Remotely Piloted Vehicle

The Lockheed developmental remotely piloted vehicle (RPV) is a highly sophisticated miniature airplane which represents the current state of the art in RPVs. The avionics, which include flight controls, inertial attitude reference, recovery guidance, payload and data link, represent more than 80 percent of the cost of the vehicle. The key cost drivers are the payload and data link which must accommodate long stand-off range and rapid AV jinking for good survivability, day and night operation, high radio jamming conditions, and high-precision laser pointing accuracy. However, there are many RPV applications which are less demanding and can therefore take advantage of substantial cost reductions. Lockheed Research & Development Division is addressing this need by defining flexible, adaptive, avionics concepts which emphasize the nondevelopmental philosophy. One such system is the Lockheed Adaptive Modular Payload (LAMP). This system promotes use of a standard universal two-axis gimbal platform into which many different forms of imaging sensors can be installed. This concept is aimed at reconnaissance and surveillance. It is now being integrated into the future RPV programs at the Lockheed Austin Division.     

应用SGCMG的卫星姿态快速机动控制

针对存在外界干扰的情况下使用单框架控制力矩陀螺(SGCMG)作为执行机构的卫星姿态大角度快速机动控制问题,设计了以Legendre伪光谱算法和滑模控制方法相结合的控制策略.采用能量与时间相结合的最优性能指标,应用Legendre伪光谱算法将最优控制问题转化成非线性规划问题,求解出能量和时间综合最优姿态机动轨迹.以该规划...     

多个MEMS惯性姿态模块同时标定方法研究

针对MEMS 惯性姿态模块的应用需求, 根据已有的MEMS 三轴加速度计和 三轴陀螺仪的零偏、标度因子和非正交等误差及其随温度的变化模型, 设计了多个 MEMS 惯性姿态模块误差同时标定的方法,该方法可实现多个模块传感器数据的同步采 集,在常温下可对多个MEMS 惯性姿态模块的非正交误差进行批量标定,在全温度范围 内同时标定多个模块的温度漂移误差。试验表明,该方法校正了MEMS 惯性传感器的非 正交误差和温度漂移误差,提高了MEMS 惯性传感器的精度,同时提高了标定的效率, 减少了标定成本,有利于工程实现。     

An Algorithm Providing All-Attitude Capability for Three-Gimballed Inertial Systems

This paper describes an algorithm which protects a three-gimballed inertial system against gimbal lock while preserving the inertial reference. One sample of the gimbal angles and gimbal angle rates for a torque-free dynamic vehicle provides the information needed to determine whether or not gimbal lock will occur at some later time. When gimbal lock is imminent, the inertial platform is commanded to a new "safe" orientation, and knowledge of the inertial reference is updated accordingly. By iterating this process gimbal lock protection is extended to a vehicle subjected to torques. The results of digital simulations using the Apollo Primary Guidance, Navigation and Control System as a model are presented for various dynamic situations.     

光学铅垂对点锥面理论与垂准仪室内检校法

提出基于空间解析几何与立体几何的光学铅锤对点锥面理论并由此给出了普通型垂准仪的一种室内简便检校法.     

速率方位惯性导航系统

本文提出一种把平台式和捷联式惯导系统结合在一起的新的惯性导航系统。在该系统中使用的速率方位平台没有方位稳定回路、方位坐标分解器及同步器。平台和运载器的方位角是根据由水平环架支承的方位速率陀螺讯号借助积分运算得到的。这种惯导系统适用于运输机、飞航式及弹道式导弹等不作大角度俯仰机动的运载器。文中叙述了方位速率平台的工作原理、力学编排方程、初始对准的特点以及陀螺漂移的标定和补偿;同时对各主要误差源所引起的姿态、速度和导航定位误差的传播特性进行了模拟计算。在结论中指出:平台的结构简单、体积小、重量轻、可靠性好、可对方位陀螺的漂移进行标定和补偿是其独特优点。另外,如果利用专门的光学系统,配合已知地标的方位角和纬度,不仅能够实现快速对准,而且还可进行水平陀螺的标定和补偿。     

Gyro Misalignment and Encoder Quantization Effects During Multi-Axis Evaluation of Strapdown Gyros

This paper presents a quantitative discussion of two error sources which affect the accuracy of data comparison between instrument outputs and reference angle computations during multi-axis evaluation of strapdown gyros. The error due to misalignment of gyro input axes is formulated in terms of closed-form solutions for typical relationships between the three table gimbal rotation histories. If the angular positions of the table gimbal axes are measured by shaft encoders, then any measurement has an uncertainty in the range from plus to minus one-half of the quantization level. It is shown that the effect of encoder quantization error on the computer transformed angles in the bodyfixed coordinate system can be divided into two parts: the initial uncertainty of the zero positions of the gimbals before table motion is begun, and all subsequent error contributions during table test. Typical data for gyro misalignment and encoder quantization error effects are presented.