Transient Performance of Gyro in Spinning Spacecraft

Transient performance of a single-axis rate gyroscope mounted in a spacecraft which is spinning about the spin axis of the gyro is presented. Analytical expressions for various time-domain and frequency-domain specifications as functions of the spin rate of the vehicle are obtained. Numerical results are presented which are useful in selecting the gyro parameters if it is to be used for the measurements of the angular velocity in spinning space vehicles.     

Gyro Motion Boundedness under Uncertain Vehicle Spin and Acceleration

An analysis is presented of the motion of a single axis rate gyroscope mounted in a space vehicle, which is simultaneously accelerating and spinning about the output and spin axis, respectively, of the gyro. The time-varying acceleration and deceleration ?x(t) and the spin rate ?z(t) of the vehicle are unknown but bounded functions of time t. It is shown that the motion of the gyro remains bounded if the bound ?*2 on the uncertainty in ?z(t) does not exceed some threshold ?*2 and that this threshold depends on the various parameters of the gyro. Furthermore, by a proper selection of the gyro parameters, its motion can be forced to remain in a small neighborhood (called region of ultimate boundedness) of the origin in ?-? plane after a certain finite interval of time for any bounded uncertain ?x(t) and ?z(t). Analytical relations are derived for the selection of gyro parameters to keep the error caused in the measurement of the input rate due to ?x and ?z within any given limit.     

Stability of 2-Degree-of-Freedom Gyro in a Spinning Vehicle

Using the Lyapunov approach, the conditions are presented for the stability of the spin axis of a 2-degree-of-freedom gyro which is mounted in a spinning vehicle.     

Stability of Gyro in a Vehicle Spinning with Uncertain Angular Velocity

The analysis of a single-axis rate gyroscope mounted in a vehicle which is spinning with uncertain angular velocity about the spin axis of the gyro is presented. The nonlinearity in the equation of motion of the gimbal is retained. Using circle criterion, it is shown that the gimbal motion is globally asymptotically stable if Nyquist plot of the linear transfer function of the gyro lies in the interior of a certain disk. A simple analytical relation for the selection of gyro parameters for stability is derived.     

Asymptotically Stable Motions of a Gyro in a Spinning Vehicle

An analysis of the motion of a single-axis rate gyroscope mounted in a space vehicle which is spinning with uncertain constant angular velocity xz about the spin axis of the gyro is presented. The nonlinearity in the equation of motion of the gimbal is retained. Using the Lyapunov approach, regions are obtained in the k-xz plane where k is the torsional spring constant, for asymptotic stability and for global asymptotic stability, and an estimate of the region of stability in state space is presented. Analytical relations for the selection of the gyro parameters are derived.     

Stability of Gyro with Harmonic Nonlinearity in Spinning Vehicle

A stability analysis of a single-axis rate gyroscope mounted in a space vehicle which is spinning with uncertain angular velocity ?z about the spin axis of the gyro is presented. The complete nonlinear equation of motion, which includes the fundamental and second harmonic nonlinear terms, arising due to ?z, is considered. For time-varying ?z(t), using the circle criterion, it is shown that the gimbal motion is globally asymptotically stable if the Nyquist plot of the linear transfer function of the gyro lies in the interior of a certain disk. For the case of uncertain constant ?z, using the Lyapunov approach, conditions for global asymptotic stability (GAS) and asymptotic stability are derived. Stable regions in parameter space of the gyro and state space are obtained. Analytical relations for the selection of gyro parameters are derived.     

高精度陆用惯导零速修正技术研究

零速修正技术是提高陆用惯导定位精度的一项有效手段。在周期性停车过程中,惯导系统除了将速度误差清零外,还能将由陀螺漂移、平台误差角等因素引起的位置误差进行补偿。本文采用离散线性卡尔曼滤波方法,通过连续三个停车时刻的速度误差构造观测向量,对惯导速度误差、加速度误差和陀螺漂移进行估计,进而补偿位置误差。车载试验表明,该零速修正方法位置精度高,且停车时间短,能够满足地面车快速响应的要求。     

Theory of Operation of an Elastically Supported Tuned Gyroscope

Detailed derivation of the transfer function for a multigimbal, elastically supported, tuned gyro is presented and comparison made between its characteristics and those of a classical two-axis, free-rotor gyro. Knowledge of the gyro transfer function is necessary for the purpose of servo analysis of the system in which the gyro is used; also, the transfer function is a basis of evaluation of errors caused by angular inputs that occur at twice spin frequency.     

陀螺动力学系统计算机仿真

推导出了适于计算机仿真的陀螺完整运动方程式并给出了仿真曲线,可看出在外力矩作用下陀螺仪从起动到稳定这一段时间内的转动角速度和转角的变化规律。通过降低陀螺转速并减小外力矩,使无锁紧机构的陀螺仪消除起动时的剧烈抖动而达到平稳起动的目的。     

弹性飞行器纵向稳定性问题

 本文研究考虑气动弹性时飞行器的纵向稳定性问题。首先由弹性飞行器的纵向扰动运动方程出发,导出了便于计算采用的弹性飞行器纵向扰动方程的标准矩阵形式,作出作为控制对象的弹性飞行器在考虑一阶、二阶及三阶振型时的传递函数;其次分析气动弹性对整个飞行器系统的稳定性的影响,并提出对飞行器自动驾驶仪敏感元件的可能合适位置选择的要求。最后还建立了计算气动弹性对飞行器气动导数值影响的理论式。     

Accurate INS Transfer Alignment Using a Monitor Gyro and External Navigation Measurements

A particular alignment mechanization for a nonmaneuvering vehicle is described which uses a monitor gyro to estimate the slave inertial navigation system (INS) equivalent east gyro drift rate and thus improves azimuth alignment. A state-space model of the dynamic system with measurements is developed. Results of covariance simulations employing Kalman filter estimation are presented for two master INS position update scenarios, one involving frequent and very accurate updates and the other including infrequent and coarse updates. The ef fects of position updates and the monitor gyro on the quality of transfer alignment are demonstrated and analyzed.     

Gyro Motion Boundedness under Uncertain Angular Acceleration about Vehicle Output Axis

An analysis of the motion of a single-axis rate gyroscope mounted in a space vehicle which has uncertain time-varying acceleration and deceleration ?x(t) about the output axis of the gyro is presented. Using a Lyapunov function, a condition for boundedness of the gyro motion is derived. It is shown that by a proper selection of the parameters of the gyro, its motion can be forced to remain in a small neighborhood (called region of ultimate boundedness) of the origin in ? - ? plane after a certain finite interval of time for any bounded uncertain ?x(t). Analytical relations for the selection of gyro parameters to keep the error caused in the measurement of the input rate due to ?x within desirable limits are derived.     

微小型无人机用微磁数字罗盘集成系统的设计

 针对现有微磁数字罗盘成本高、输出频率低、动态定姿时易发散等问题,结合微小型无人机(MUAV)导航与控制系统的组成特点,设计了一种利用MUAV机载微惯性测量单元(MIMU)中的天向陀螺输出判断无人机的运动状态,采用MIMU中的3轴加速度计组件测量的地球重力矢量,配合3轴磁阻传感器测量的地球磁场矢量,共同进行姿态确定的微磁数字罗盘集成系统。对传统的环境干扰磁场校正方法进行了完善与验证,使之适合于空间三维定姿。试验结果表明：系统总体性能良好,航向精度可达0.5°,成本为同类产品的1/5,输出响应可达50 Hz,满足应用于MUAV导航控制系统的微磁数字罗盘的高精度、低成本和实时性的要求。     

一种新型机载对地观测用三轴稳定平台陀螺安装方式

陀螺安装方式及相应的算法编排是稳定平台设计中的一项关键技术。针对机载对地观测用三轴稳定平台特点,提出了将方位陀螺安装在方位环上,俯仰陀螺和横滚陀螺安装在俯仰环上的陀螺安装方式。利用空间矢量分解理论分析了陀螺输出角速度信号的投影关系及电机控制信号的分配;基于稳定平台系统模型,对理想正交情况和考虑陀螺安装误差情况进行了仿真分析,验证了此种安装方式的可行性和优越性。分析表明,在同等条件下,所提出的安装方式减小了稳定平台的机械尺寸,降低了稳定平台的重量和功耗,实现了三维角速度的正交测量,简化了三轴解耦控制算法。研究结论可为其他三轴稳定平台结构设计和陀螺安装方式设计提供参考。     

基于EMD-SVR的光纤陀螺随机误差预测

为了提升光纤陀螺随机误差建模的准确性及补偿结果,提出了一种基于经验模态分解与支持向量机结合的随机误差预测方法。鉴于随机误差的非线性及不稳定性,直接进行预测时精度不高,采用经验模态分解对原始数据进行分解以降低时间序列的复杂程度;然后根据经验模态分解得到的各本征模态函数及趋势序列,构建基于支持向量机的预测模型;再将所得的各分量的预测结果综合以得到光纤陀螺随机误差的预测结果。以光纤陀螺随机误差数据作为验证,结果表明,相较于传统的预测方法,均方根误差与平均绝对误差分别降低了78.4%和75.5%,有效提高了回归精度。     

激光陀螺机械抖动偏频对等效转动矢量姿态计算的影响

研究了激光陀螺机械抖动偏频影响等效转动矢量姿态计算精度的机理。用双子样N次迭代算法推导了载体实际姿态角运动与机械抖动发生谐振时产生的姿态计算误差项,指出其误差作用机理与惯性导航比力方程计算中划摇误差的相似性。针对三轴激光陀螺共一个机械抖动轴和3个单轴激光陀螺构成惯性组合两种情况进行了讨论。根据对静态条件下惯性组合中激光陀螺采样信号的功率谱密度分析,指出当采样频率较低时,会产生与抖动有关的低频周期分量,与低频的载体姿态运动谐振将产生姿态计算误差,应尽量提高采样频率及等效转动矢量计算频率。     

Magnetically suspended MEMS spinning wheel gyro

A concept of a magnetically suspended spinning wheel gyro is described. The gyro is based on a patented, planar magnetic actuator and position sensor configuration with a gyro wheel that is rotated by a multi-phase electromagnetic spin motor. The motor and actuator/sensor configurations, in addition to providing the necessary forces to suspend the spinning wheel, are amenable to fabrication using some of the developing MEMS fabrication technologies, making batch fabrication of the gyro possible. This provide the capability for high production yield in high volume through the use of batch processing, without the need for skilled hand labor, resulting in high yields, high reliability, and low cost of ownership. The gyro concept is described in detail. The high-speed rotation of the wheel, somewhat smaller than a dime, can produce an angular momentum much larger than that of the Coriolis force based MEMS gyros now receiving intensive development, and is expected to provide considerably higher performance than currently available from this class of instrument. Two axes of angular rate information and three axes of acceleration information are provided by the control loops that center the wheel within the case. Thus, two such magnetically suspended spinning wheel gyros can be used to implement a complete IMU, and can also provide redundancy in three of the five degrees of freedom     

有缺陷圆柱壳振型进动的研究

谐振陀螺是一种不存在高速转子和活动支承的新型陀螺仪。其敏感部件是一个轴对称壳谐振子,圆柱壳便是其中一种。本文建立了圆柱壳在旋转情况下的动力学方程。研究了有缺陷的圆柱壳谐振子振型的进动情况;分析了其环向振型进动因子的相对扰动和绝对扰动;给出了圆柱壳谐振子环向缺陷对其振型进动特性的影响规律及实际加工,选择谐振子的准则。这些对于设计谐振陀螺有指导意义。     

Inertial System Platform Rotation

Differential error equations are derived for the navigation errors of a local level undamped pure inertial platform that continuously rotates in azimuth. From these, the time response equations for the vector position error produced by a constant level gyro drift error, as a function of platform rotation rate, are computed and evaluated. It is shown that platform rotation attenuates the system position error due to level gyro bias and that this attenuation is a nonlinear function of rotation rate.     

FUTABA陀螺仪的辨识及在无人机中的应用

通过对FUTABA陀螺仪GYA351各参量之间静态关系的分析和动态特性的辨识,得到了该模块在NORMAL工作模式下的数学模型,并给出了该陀螺仪在摄像无人机滚转控制通道中的应用实例。