1.2米高速风洞外挂物可控轨迹系统中的测,控,处系统

气动中心１．２米高速风洞外挂物可控轨迹系统中测，控，处系统是一个由电子计算机闭环控制以获得外挂物由其母机上分离的轨迹的大系统，已多次成功有竽测定外挂物分离轨迹的试验，表明其操作方便，控制灵活和可靠，精度高，抗干扰能力强，适用于进行各种外挂物的可控轨迹试验。     

一种提高风洞动态试验数据质量的模型姿态控制和测量技术

低速风洞动态试验装置通常采用“电机+减速器+偏心机构+线性传动机构”的方式,存在传递环节多、机械间隙大等问题,给模型运动的精确控制和模型姿态的精确测量带来较大困难。为满足大型客机等大飞机对低速风洞动态试验的要求,基于现有的静态试验通用支撑平台,采用“电子凸轮”技术,建立了一套迎角/侧滑角解耦、可进行飞机小振幅动导数和大振幅非定常气动特性研究的动态试验装置。利用该动态试验装置进行了某飞机大尺度动态试验模型动导数试验和大振幅振荡试验,获得了试验数据的重复性,并研究了动态试验数据和静态试验数据之间的相关性。试验结果表明：利用该装置获得的某飞机动态试验数据重复性较好、规律合理,能满足大型飞机动态试验要求。     

借助气动力特性计算和外挂物分离分析研究飞行试验事故

外挂物分离委员会研究的方法已用于对包括从飞机上发射改进的假目标的飞行试验事故的研究，气动力特性计算已用于评定飞机对原始和改进的外挂物的影响，以确定了飞行试验事故的原因，用假目控制系统模型和六自由度外挂分离轨迹的代码及该流场的模型一起再现试验事故，然后对导致可接受分离特性的假目标的变化进行分析检查。     

捕获轨迹系统并联机构地面标定方法

捕获轨迹系统（CTS）是一种先进的预测外挂物投放轨迹的试验系统，普遍采用六自由度（6-DoF）串联机构作为其运动机构，串联机构因惯性力大和关节累积误差大使其定位精准度不足。相比串联机构，并联机构具有惯性力小和关节误差不累积等优点。采用6-PTRT并联机构作为CTS试验系统的六自由度运动机构，在空间受限的风洞环境中对CTS并联机构进行地面标定：提出动平台位姿的测量和计算方法，建立包含直线驱动平台安装夹角修正的标定模型，并基于非线性最小二乘法辨识结构参数。辨识后CTS并联机构的位移定位准度优于0.1 mm，姿态定位准度优于0.05°，最后以CTS并联机构和常规攻角机构进行8#标模的对比风洞试验。风洞试验结果表明，CTS并联机构的风载定位准度满足测力试验精准度要求。     

基于LMI的航空发动机鲁棒H_∞控制器设计

 研究了系统矩阵均具有参数不确定性系统的非标准H_∞鲁棒控制问题。基于 LMI的H_∞控制器设计方法,给出了参数不确定性系统用 3个线性矩阵不等式表征的非标准H_∞控制问题可解的充分必要条件,采用“内点法”求解线性矩阵不等式,可得使闭环系统对于所有可能的参数不确定性均二次稳定且传递函数的H∞ 范数 γ有界的鲁棒控制解。该方法应用于非“标准”系统——某型双转子涡喷发动机稳态双变量调节控制器的设计,通过在气动热力学模型上的仿真结果表明,取得了良好的结果。     

基于摩擦补偿的空间机械臂关节高精度控制研究

空间机械臂关节具有大惯量、高精度的特点,针对空间机械臂关节低速、高精度控制要求,提出一种基于摩擦补偿的双位置闭环控制策略。建立了考虑摩擦和惯量变化等因素的一体化关节动力学模型,分析了全位置闭环系统的稳定性,在此基础上提出了一种基于双位置传感器信息的闭环伺服控制策略,并引入自适应率辨识未知摩擦和惯量变化,利用Lyapunov函数证明闭环系统的稳定性和跟踪误差的渐进收敛性。在测试平台上的试验结果表明,提出的空间机械臂一体化关节伺服控制策略能够有效地提高关节伺服控制精度和系统鲁棒性。     

1.2m高速风洞CTS装置新控制系统及其应用研究

为了满足当前目益增多的外挂物捕获轨迹试验的需要，急需提高1.2m高速风洞CTS装置原控制系统的可靠性和稳定性。采用以工控机为核心，以5650伺服控制器和PDC伺服驱动单元为主要模块的控制系统，代替了原来以单板机为核心的控制系统，并已成功地应用到多项型号分离轨迹试验中，风洞试验表明，新的控制系统有其突出的特点，其稳定性，可靠性，位置控制能力和试验效率均有较大的提高。     

捕获轨迹试验的数据三维实时图形显示技术

应用微软的DirectX8．1图形接口，编制了具备多种显示方式的捕获轨迹试验（CTS）的投放物轨迹及姿态的三维实时图形显示模块。将该模块嵌入CTS数据处理程序中，可在实验过程中实时地以任意视角观察投放物相对母机的位置及姿态，并可在实验结束后逐点重现投放过程或演示投放动画。本技术的应用，增强了试验人员分析和掌握试验进程的能力，有助于提高试验效率。     

考虑避免碰撞的编队卫星自适应协同控制

基于势函数法研究具有模型不确定性的编队飞行卫星避免碰撞的自适应协同控制.势函数法的思想为设计碰撞区域势函数值较大,所设计的控制律使得系统势函数具有减小的趋势,从而实现避免碰撞的编队飞行任务.首先,在无外部参考轨迹的情况下,通过引入避免碰撞势函数,提出一种自适应协同控制器,编队卫星最终实现速度一致和避免碰撞.进一步,考虑已知外部参考轨迹的情形,基于新的势函数方法,设计新的自适应协同控制器,能够同时实现避免碰撞、速度一致、卫星跟踪参考轨迹的目的.对于所提出的两种控制方法,均通过合理地应用Lyapunov稳定性理论分析了闭环系统的稳定性.仿真结果表明了所设计控制方法的有效性.     

捕获轨迹法在××无人机投放试验中的应用

介绍一种投放外挂物脱离母机状态的风洞测力试验和飞行轨迹分析融于一体的“捕获轨迹”方法。该方法能较精确地获得外挂物在复杂干扰流场中所受的空气动力和力矩，实时地提供离机后的轨迹和姿态，预测了无人机和母机之间飞行是否相容的问题。全尺寸的飞机投放试验表明，“捕获轨迹”技术是一种精确预测外挂物分离特性的方法，解决了大展弦比无人机安全离机的关键问题。     

Trajectory and attitude deviations for internal store separation due to unsteady and quasi-steady test method

The deviations of trajectory and attitude angle for internal store separation are evaluated by two wind tunnel test methods. One is the Freedrop Test(FDT), which is known as unsteady and time-dependent method of scaled model. The other is the Captive Trajectory System(CTS) test,which is usually regarded as a quasi-steady and time-averaged test technology. The result shows that there is a streamwise adverse pressure gradient on the cavity resulting in a nose-up pitching moment coefficient(>0) ...     

Adaptive vector field based accurate homing control of aerial delivery systems

This paper investigates the homing control problem of a flexible aerial delivery system with external wind, at-mospheric turbulence, and aerodynamic uncertainties. An accurate homing control strategy is presented, consisting of a trajectory generation algorithm and a lateral tracking controller. A high-altitude trajectory generation is de-veloped with system characteristics explicitly considered to generate the desired trajectory for the aerial delivery control system design. It significantly compensates for the altitude deviation of the existing multiphase theory based trajectory generation methodologies. A novel adaptive vector field control law is then designed to accom-plish the lateral tracking maneuvers. The key feature of the proposed method is that the complete lateral closed-loop control, including position and heading angle loops, is achieved in the presence of disturbances and dynamic uncertainties. The homing control with high landing accuracy is therefore achieved. Simulation and hardware-in-loop testing results are finally presented to validate the proposed method’s effectiveness compared to a conventional homing control scheme.     

一种IRST双机协同被动探测机动目标定位新方法

针对红外搜索跟踪系统（IRST）双机协同被动探测定位作战使用中，机动目标建模与实际运动失配造成定位误差偏大的问题，研究了一种基于曲线模型的自适应滤波新方法。该方法改进了传统方法根据方向角估计转弯率以及基于帧间插分线加速度估计切向加速度的思路，将转弯率及线加速度联合作为状态变量进行了状态扩维，并推导了扩维后的过程噪声协方差表达式，在缓解传统两层滤波结构带来的计算量大问题外，也提高了切向加速度的估计精度。另外基于反正切函数的值域，结合方向角在四象限间的转移关系，优化了方向角的设计。通过IRST双机协同仿真实例，验证了所提方法对机动目标的适应性更强、目标定位精度更高。     

Experience in the use of computational aerodynamics to predict store release characteristics

In the early days, store separation tests were conducted in a hit or miss fashion—the stores would be dropped from the aircraft at gradually increasing speeds until the store came close to or sometimes actually hit the aircraft. In some cases, this led to loss of the aircraft, and made some test pilots reluctant to participate in store separation flight test programs.During the 1960's, the Captive Trajectory System (CTS) method for store separation wind tunnel testing was developed. The CTS provided a considerable improvement over the hit or miss method, and became widely used in aircraft/store integration programs prior to flight-testing. However, since fairly small-scale models had to be used in the wind tunnel tests, in many cases the wind tunnel predictions did not match the flight test results. No mechanism was then in place to resolve the wind tunnel/flight test discrepancies.During this same time frame Computational Fluid Dynamics (CFD) had finally matured to the point of providing a trajectory solution for a store in an aircraft flowfield. However, since the computational tools were necessarily (due to computer resource limitations) limited to linear techniques, and since most store separation problems occur at transonic speeds, these tools had limited application.Recent advances in computer resources have greatly improved the capability of CFD to predict store release characteristics. Instead of using linear or approximate schemes, time dependent Euler and Navier Stokes trajectories could be computed in a reasonable time frame.Three international CFD Challenges, held during the last decade of the 20th century, have shown that CFD can not only match wind tunnel test data, but also predict flight test trajectories for complex stores at transonic speeds. It appears that CFD has matured to the point that it can be usefully integrated into aircraft/store compatibility programs.     

风洞模型投放试验轻模型法重力效应影响

风洞模型投放试验是研究超声速机弹分离问题的一种有效手段，相似参数的选取是影响试验准度的关键因素。有初始弹射速度的超声速机弹分离研究中，通常采用"轻模型法"得到模型的运动学及动力学相似参数，但该相似参数中模型重力模拟不足。为了研究重力效应对投放试验结果的影响，采用CTS试验技术对全尺寸真实参数与缩比尺寸轻模型法相似参数条件下得到的结果进行了对比研究。研究结果表明：在载弹与载机分离过程中，载弹位姿相互耦合，垂直下落位移的快慢会影响载弹姿态角的变化；轻模型法相似参数条件下，载弹垂直下落位移较慢，虚拟重力的修正方法只能近似修正下落位移，不能对导弹姿态角进行修正，而姿态角会影响下落的位移；机弹分离安全性方面，轻模型法相似参数条件下的试验结果较真实参数偏危险。     

Optimization and verification of free flight separation similarity law in high-speed wind tunnel

Based on the similarity of separation time, a similarity law optimization method for high-speed weapon delivery test is derived. The typical separation state under wind load is simulated by the numerical method. The real separation data of aircraft, separation data of previous test methods, separation data of ideal wind tunnel test of previous methods, and simulation data of the proposed optimization method are obtained. A comparison of the data shows that the method proposed can improve the performance of tracking. Similarity law optimization starts with the development of motion equations and dynamic equations in the windless state to address the problems of mismatching between vertical and horizontal displacement, and to address the problems of separation trajectory distortion caused by insufficient gravity acceleration of the scaling model of existing light model. The ejection velocity of the model is taken as a factor/vector, and is adjusted reasonably to compensate the linear displacement insufficiency caused by the insufficient vertical acceleration of the light model method, so as to ensure the matching of the vertical and horizontal displacement of the projectile, and to improve the consistency between the test results of high-speed projection and the actual separation trajectory. The optimized similarity law is applicable to many existing free-throwing modes of high-speed wind tunnels. The optimized similarity law is not affected by the ejection velocity and hanging mode of the projectile. The optimized similarity law is suitable not only for the launching of the buried ammunition compartment and external stores, but also for the test design of projectile launching and gravity separation.     

Sliding mode tracking control for miniature unmanned helicopters

A sliding mode control design for a miniature unmanned helicopter is presented. The control objective is to let the helicopter track some predefined velocity and yaw trajectories. A new sliding mode control design method is developed based on a linearized dynamic model. In order to facilitate the control design, the helicopter’s dynamic model is divided into two subsystems,such as the longitudinal-lateral and the heading-heave subsystem. The proposed controller employs sliding mode control technique to compensate for the immeasurable flapping angles’ dynamic effects and external disturbances. The global asymptotic stability(GAS) of the closed-loop system is proved by the Lyapunov based stability analysis. Numerical simulations demonstrate that the proposed controller can achieve superior tracking performance compared with the proportionalintegral-derivative(PID) and linear-quadratic regulator(LQR) cascaded controller in the presence of wind gust disturbances.     

Trajectory control strategy of cathodes in blisk electrochemical machining

A turbine blisk, which combines blades and a disk together, is one of the most important components of an aero engine. In the process of blisk electrochemical machining (ECM), the sheet cathode, which is usually used as a tool electrode, has a complicated structure. In addition to that, the channel between the adjacent blades is narrow and twisted, so interference is apt to happen when the sheet cathode feeds into the channel. Therefore, it is important to choose suitable trajectory control strategy. In this paper, a new trajectory control strategy of the sheet cathode is presented and corresponding simulation analysis is conducted on the basis of an actual blisk model. The simulation results demonstrate that the sheet cathode can feed into the channel by a spatial line trajectory without interference. Moreover, the verification experiments are carried out according to the simulation. The experimental results show that the cathode can move into the channel without interference. It is verified that the new trajectory control strategy is correct and can be used in the blisk ECM process successfully.     

对失控航天器在轨服务的自适应滑模控制器设计

为实现对自由翻滚的失控目标航天器进行在轨服务,基于二阶滑模控制算法设计了相对位置与姿态耦合的自适应控制器。考虑相对转动对相对平动的耦合作用,建立了两航天器对接端口间相对位置与姿态耦合的动力学模型,并在此基础上设计了自适应Super twisting控制器,以减弱已知界限的有界干扰所产生的震颤效应,使闭环系统在有限时间内收敛到平衡点。利用李雅普诺夫方法证明了有界干扰下的闭环系统稳定性,并对收敛时间的上界进行了估计。仿真结果表明,与Super twisting算法相比,所设计的自适应二阶滑模控制器对参数不确定性及线性增长有界干扰具有较强的鲁棒性,且控制精度满足在轨服务的任务需求。