同步磁阻电机定子电流最优控制

针对磁路饱和对同步磁阻电机运行特性的影响,提出了定子电流最优控制策略。通过有限元法对电感与电流的非线性关系进行拟合,并利用拟合结果得到最优定子电流随转矩变化的运行轨迹,以实现同步磁阻电机最大转矩电流比(MTPA)控制;同时对于交直轴电流环相互耦合的问题,提出磁路饱和补偿的电流环设计,以提高其动静态性能。仿真与试验结果验证了该方案的有效性。     

基于反熔丝FPGA的纯开环星载步进电机驱动器设计

为了提高运动机构的稳定度,步进电机驱动控制通常采用电流细分的方法,从而将一个步距角分解成若干小步。实现步进电机电流细分驱动通常的方法是将电流闭环引入到驱动控制电路中,由此增加电流采样、比较等软硬件功能模块的同时也增加了单机的复杂度,削弱了步进电机本质上开环驱动的优势。为了提高宇航型号步进电机驱动控制器单机的可靠度,提出了一种基于反熔丝FPGA的纯开环驱动方案,通过预置占空比的方式,在不引入电流闭环的前提下实现步进电机电流细分。通过样机调试,验证了设计的有效性,为后续工程研制提供参考。     

Lock threshold deterioration induced by antenna vibration and signal coupling effects in hypersonic vehicle carrier tracking system of Ka band

The envelope of a hypersonic vehicle is affected by severe fluctuating pressure, which causes the airborne antenna to vibrate slightly. This vibration mixes with the transmitted signals and thus introduces additional multiplicative phase noise. Antenna vibration and signal coupling effects as well as their influence on the lock threshold of the hypersonic vehicle carrier tracking system of the Ka band are investigated in this study. A vibration model is initially established to obtain phase noise in consideration of the inherent relationship between vibration displacement and electromagnetic wavelength. An analytical model of the Phase-Locked Loop(PLL), which is widely used in carrier tracking systems, is established. The coupling effects on carrier tracking performance are investigated and quantitatively analyzed by imposing the multiplicative phase noise on the PLL model. Simulation results show that the phase noise presents a Gaussian distribution and is similar to vibration displacement variation. A large standard deviation in vibration displacement exerts a significant effect on the lock threshold. A critical standard deviation is observed in the PLL of Binary Phase Shift Keying(BPSK) and Quadrature Phase Shift Keying(QPSK) signals. The effect on QPSK signals is more severe than that on BPSK signals. The maximum tolerable standard deviations normalized by the wavelength of the carrier are 0.04 and 0.02 for BPSK and QPSK signals,respectively. With these critical standard deviations, lock thresholds are increased from à12 andà4 d B to 3 and à2 d B, respectively.     

基于光纤双环网的高精度时频同步技术研究

本文介绍了一种基于光纤双环网的时频同步技术设计方法，针对时频设备协同使用时如何获得高精度同步指标这一问题提出了一种设计思路。以系统时间源使用北斗/GPS/GLONASS，本系统同步精度优于5E-13，频率稳定度优于5E-13@1d；以UTC(BIRMM)输出的TOD+1PPS做系统时间源，本系统同步精度优于4E-13，频率稳定度优于6E-14@1d。本方案提出的方法原理简单，系统可根据使用情况进行裁剪，相比卫星双向等手段成本低廉，适合在时频同步领域推广。     

基于光星模拟器的星敏感器安装极性测试方法

针对目前星敏感器在整星上的安装极性无法被直接测试的问题，提出了基于光星模拟器的星敏感器安装极性测试方法,从物理和数学两方面阐述了该测试方法的原理，设计了星敏感器安装极性的操作方法和相应的判据。提出了可测性指标的概念，并通过对星敏感器极性和星敏感器安装极性分别进行可测性分析，证明了该方法的有效性。整星电测试结果表明，该方法操作简单，效果直观，可广泛应用。     

强实时条件下光纤通道仲裁环带宽分配方法

光纤通道是一个为适应高性能信息传输要求而提出的计算机通讯协议,仲裁环是光纤通道的基本拓扑结构之一.为解决网络消息集实时发送的问题,研究了光纤通道仲裁环拓扑在强实时条件下的通信性能.依据实时系统中的周期任务模型和光纤通道仲裁环协议规定的访问公平机制,采用负载匹配算法提出了一种适用于仲裁环网络的带宽分配方法.推导并证明了采用该方法时在最坏情况下消息集强实时的网络可达负载率不低于50％.     

Spiking-free HGO-based DSC for flexible joint manipulator

The tracking control problem for Flexible Joint Manipulator Control System(FJMCS)with unmeasurable states is addressed in this paper. Firstly, a High-Gain Observer(HGO) is constructed to estimate the unmeasurable states and the uncertainties. Then, a Dynamic Surface Control(DSC) scheme is developed by using the estimation of HGO. The newly proposed controller has two advantages over the existing methods:(A) a novel Spike Suppression Function(SSF) is developed to avoid the estimation spike proble...     

Constrained adaptive fault-tolerant attitude tracking control of rigid spacecraft

A saturated fault-tolerant attitude tracking controller for disturbed rigid spacecraft is derived using nonlinear state feedback control method. The proposed controller achieves the constraints of control inputs by directly using the bounded function instead of the traditional saturation compensator technique, and the active tolerance to the partial loss of actuator effectiveness is also achieved by directly using the known bounds of the actuator faults in the controller. Specifically, compared with the traditional saturated control methods, a continuously bounded nonlinear function in the proposed controller is used to guarantee that the actuator outputs are smoothly bounded under the prescribed constraints. Based on some properties of the attitude tracking dynamics, the proposed controller can ensure the attitude tracking errors converge to small neighborhoods of zero via stability analysis in the Lyapunov framework. Simulation results are presented to illustrate the effectiveness of the control scheme.