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载人飞船的一种混合再入制导方法 总被引:2,自引:2,他引:2
提出了载人飞船的一种混合再入制导方法,即在制动段结束后的过渡段,利用落点预报及其制导规律在轨生成一条基准再入弹道,在再入段利用基准弹道制导规律实现再入升力控制的一种方法。该方法融合了落点预报制导方法和基准弹道制导方法的长处。相对基准弹道制导方法,该方法可对付较大的初始误差,达到较高的精度;相对落点预报制导方法,在再入段减少了计算量。数学仿真结果验证本方法是有效的。 相似文献
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Aleksashkin S. N. Bobylev A. V. Vlasenko O. V. Pichkhadze K. M. Terterashvili A. V. Yaroshevsky V. A. 《Cosmic Research》2003,41(3):280-284
The possibility of using an inflatable braking device for controlled descent in the Martian atmosphere of large-capacity cargoes is analyzed. The most complicated version of the trajectory control problem is considered, namely, the injection of a spacecraft at hyperbolic velocity into a parking orbit after braking in the atmosphere. 相似文献
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针对再入过程中标准轨迹的实际长度需要通过多次更新或迭代求解的问题,提出了一种基于机动系数的通用再入轨迹设计方法。该方法将机动系数定义为真实轨迹长度与初始纵程之比,将再入过程中的机动性进行了量化,可以快速获得到达指定目标可行的轨迹长度;采用真实轨迹长度作为设计参考阻力加速度剖面的依据,避免了轨迹长度的迭代,简化了再入轨迹的生成流程;轨迹曲率问题采用动态航向偏差走廊的方法,控制终端航向偏差、剩余航程满足设计需求。设计轨迹跟踪控制器进行参考轨迹跟踪,完成再入制导。在机动系数区间内指定机动系数进行了数值仿真。仿真结果表明,所提出的标准轨迹制导方法能够快速生成满足路径及终端约束的标准轨迹,且轨迹跟踪效果良好,有较好的应用潜力。 相似文献
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This report deals with the problems of synthesizing algorithms for controlling the attitude manoeuver of a transport spacecraft aimed at injecting the spacecraft into a closed terminal domain of “heading-range” phase coordinates which makes it possible to descend to the landing aerodrome region in accordance with a spiral trajectory tracking pattern. The descent trajectory is controlled by changing the roll angle. The principal distinguishing feature of the suggested method of transport spacecraft lateral motion control resides in guiding the spacecraft to a terminal curve and in providing an automatic transfer from roll control to interacting control of roll angle and angle of attack. The performance of the control algorithm under transient conditions are considered in detail.Algorithms controlling the longitudinal range by varing the magnitude of the roll angle and lateral range by selecting the respective sign of the roll control angle are thereafter synthesized separately. The major problem in designing the angular motion control system of transport spacecraft is the development of a high-rate roll axis turn control algorithm. To ensure high accuracy of lateral manoeuvering of the spacecraft it is expedient to accomplish the spacecraft reorientation in roll in a minimum time. It is therewith necessary to take into account with the sideslip angle limitation associated with the need of complying the design conditions of the spacecraft flowaround and with the spacecraft skin selected temperature conditions. It is expected that the total side slip angle is acceptable for measurement. Within the greater portion of the descent trajectory constant-thrust jet-reaction control engines are employed as actuators. Therefore, together with the high speed of response developed control algorithm provides an adequate efficiency of the system from the viewpoint of fuel consumption. The possibilities offered by the suggested algorithms controlling the lateral motions of the center of masses and around the center of masses during the descent stage and in the course of landing approach manoeuvering are illustrated by an example considering a hypothetical transport spacecraft featuring variable aerodynamics and a low frequency of natural oscillations of the angular motion loop. The suggested algorithms make it possible to fully employ the transport spacecraft maneuverability and to meet the terminal heading and velocity requirements within a wide class of disturbances. 相似文献
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载人飞船全系数自适应再入升力控制 总被引:7,自引:0,他引:7
本文从控制角度分析载人飞船再入升力控制的特点,将全系数自适应控制方法应用于载人飞船的升力控制研究中,并就落点精度、最大过载、燃料消耗、姿态平稳性等几方面,同制导理论中经典的标准弹道升力控制、落点预报算法中的PID算法进行了仿真比较,证明了本文方法的优越性。 相似文献
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针对以飞轮为执行机构的空间飞行器进行姿态大角度机动递阶饱和控制。在初始状念任意,反作用轮输出力矩受限、速率饱和约束条件下,提出递阶饱和的变结构机动策略,即针对飞行器的运动学模型,利用飞行器的误差四元数和角速度,通过绕瞬时欧拉轴旋转,引入误差凹元数限幅器,对姿态偏差进行逐次消除,提出了不需事先规划轨迹的绕欧拉轴逐次逼近控制算法。并且引入模糊推理规则来改进递阶饱和变结构控制设计,使得系统轨迹既能快速趋近滑动面又能降低抖振,有效减弱了一般变结构控制律中抖振问题,从而提高了变结构控制律的品质。 相似文献
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飞船返回地球时再入速度很大,过大的过载和气动加热率尤其对载人飞船带来安全性问题。如果利用航天器在大气层外及其边缘处多次再入运动,可降低速度、耗散热量。文章主要分析了载人飞船在大气层外多次再入飞行时的各主要参数对飞船轨道和轨道终点的影响。在分析过程中,首先建立了飞船在大气层外飞行的数学模型,进而通过大量的数值仿真得到一条基准轨道,在此基础上分别改变轨道起始点参数(倾角、偏航角和飞行速度)的初始值,分析轨道的特性及轨道的终点误差。最后根据起始点参数值和对应的轨道终点误差值的关系,得到了飞船在大气层外飞行时的起始参数对飞行轨道及轨道终点影响的敏感度,从而为工程上轨道的设计提供一个有效的参考依据。 相似文献
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提出一种升力式再入航天器进入稠密大气后的轨迹规划方法。在预先设定攻角剖面的前提下,利用路径约束(驻点热流、动压和过载)在高度-速度(H-V)剖面内直接获得轨迹下边界;利用终端约束确定以轨迹下边界为基准的高度增量,进而通过下边界与高度增量的加和形成满足要求的再入轨迹。其中,增量的形式选取为分段二次型函数,其大小可通过割线法快速获得。倾斜角大小可根据纵向动力学方程反解得到,其方向依据航向误差角走廊确定。通过对典型工况的仿真,结果表明所提方法能够快速规划出再入轨迹,且适应性好。 相似文献
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着陆小天体的自主GNC技术 总被引:4,自引:1,他引:4
由于目标小天体和地面站之间存在较长的通讯延迟,加之小天体的动力学环境复杂多变,传统的基于深空网的导航、制导与控制(GNC)模式已不再适合探测着器着陆小天体。为了实现安全着陆小天体,探测器必须具有自主导航、制导和控制的能力。本文提出了一种着陆小天体极区的自主GNC方案:首先,基于对自然特征点的自动提取、跟踪,给出了一种着陆小天体的自主光学导航方案;接着,为了安全垂直着陆小天体的极区,设计了比例-微分控制器跟踪理想的下降轨迹、消除侧向位置和速度偏差;最后,通过数值仿真对本文所提方案的可行性进行了验证。 相似文献
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弹道式再入飞行器一般为轴对称旋成体,但其质心可以偏离对称轴。我们称通过飞行器质心和对称轴的平面为飞行器的对称面。这种飞行器以配平攻角状态返回时,不仅要求其相对于地球的飞行速度矢量平行于飞行器的对称面、飞行攻角恰等于配平攻角,而且要求其相对于质心的转动角速度矢量垂直于飞行器的对称面,能使飞行器的姿态跟随飞行速度矢量的改变。基于上述考虑,本文给出了这种飞行器以配平攻角状态返回的轨道计算原理及相应的控制要求。 相似文献
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基于气动辅助变轨的变气动外形飞行器概念研究--最优控制律问题 总被引:3,自引:0,他引:3
从一个天地往返飞行器的上升轨道和再入返回轨道的优化,以及适用不同飞行任务的变轨要求的气动外形问题,提出一项基于气动力辅助变轨的变气动外形飞行器的新概念研究。对于一个固定气动外形飞行器要同时满足上升轨道有效载荷最大和再入轨道热流峰值、过载峰值及机动性能约束下的成本最低往往是困难的。若同时满足不同飞行任务:飞往太空站的运输任务,空间拦截和交会机动巡航任务及星际探测任务,则更为困难,实际上是不可能的。文章研究基于气动力辅助变轨,在热流约束下,气动外形参数变化对最优控制的影响。其结论为:热流约束下的最优控制解,包括考虑推力协同变轨,除了在非约束弧的滚转角不直接受气动外形影响外,其余的控制律,升力系数和滚转角都是气动外形参数和攻角的函数。因而变气动外形可作为一项新技术,即通过气动外形参数变化和相应的变轨策略而获得性能和成本都最佳的用途很广的一种新型飞行器。 相似文献
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Navigation, control and guidance of the propulsive phase of planetary landing, e.g. on Mars (or the Moon), with a soft landing being the only target, are driven by Inertial Measurement Units and a radar altimeter/velocimeter. Their measurements are affected by bias and scale errors. The latter ones are aggravated by the attitude navigation error as it accumulates during the ballistic (and aerodynamic) flight after orbiter separation and couples for most of the descent trajectory with the vehicle axis inclination from the local vertical direction. By complementing the center-of-mass dynamics with appropriate disturbance state equations driven by noise vectors and estimating the noise from the model error (plant measurements minus model output), scale errors and bias can be retrieved in real time in the form of disturbance state variables. Although a similar complement is adopted in the standard navigation algorithms, it takes the form of an output disturbance, which may lead to unobservability. In this paper instead, the disturbance complement is designed to be fully observable, which may require that the derivatives of smooth systematic errors be pushed up to the command channel (a form of back-stepping). It is then viable, unlike standard navigation, to eliminate them from position and velocity tracking errors through disturbance rejection, under appropriate convergence conditions and sensor layout. It will, however, be demonstrated in this paper that the same result cannot be achieved under pure feedback control. Since constant errors (bias) become zero through back-stepping, a well known fact derives: bias can only be eliminated by disposing of supplementary sensors.To further enlighten and solve the question of bias rejection, a further case study is treated. The attitude control of drag-free satellites is considered, where fine accelerometers allow for the rejection of wide-band aerodynamic torques (think of low-Earth orbit spacecrafts) at the price of attitude divergence because of accelerometer bias and drift. The spacecraft attitude can be made bounded and accurate, if bias and drift are modeled as angular accelerations, affecting the attitude. They are estimated by attitude sensors like star trackers and then are rejected by the attitude control. The results in the soft landing and drag free case studies are illustrated by simulated runs and Monte Carlo trials. 相似文献
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基于雷达跟踪仿真的滑翔式再入弹道突防性能分析 总被引:2,自引:0,他引:2
从防御雷达对再入弹道跟踪效果的角度,对滑翔式再入飞行器的突防性能进行了初步分析。基于Unscented卡尔曼滤波和考虑气动模型的目标跟踪模型,加入雷达测量噪声,计算目标跟踪误差,比较弹道式与滑翔式再入弹道的跟踪效果。仿真结果表明:(1) 滑翔式再入弹道有横向机动且飞行高度较低,雷达的发现时间较晚,可观测时间比较短;(2) 由于雷达的跟踪动力学模型中很难对气动力准确建模,滑翔式弹道借助气动力产生机动,雷达对其跟踪的误差要大于弹道式再入弹道; (3) 在相近的雷达观测条件下,弹道机动性越强,雷达跟踪精度越差;(4) 尽量使防御方所假设的目标动力学模型失配是增加突防能力的有效措施。 相似文献
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针对弹道再入目标轨迹跟踪问题,提出基于混合建议分布的平方根容积求积采样粒子滤波(HPD-SRCQSPF)算法,该算法以混合建议分布为框架,由两个基本建议分布组成。其中一个基本建议分布为先验分布,另一个基本建议分布为平方根容积求积卡尔曼滤波估计后的值。该混合建议分布与真实的后验分布很接近,因此有着高效性、高精度等特点。仿真结果表明,对于弹道再入目标轨迹跟踪模型,相比于标准粒子滤波(SPF)算法和平方根容积求积粒子滤波(SRCQPF)算法,HPD-SRCQSPF算法可以在较低运算负载的情况下获得更好的跟踪性能。特别是在弹道目标变轨机动的情况时,所提出算法的性能增益更为显著。 相似文献
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遗传算法在载人飞船返回轨道一体化设计中的应用 总被引:1,自引:0,他引:1
载人飞船返回再入轨道设计的主要任务是确定出标准返回轨道和再入制导规律。遗传算法具有全局寻优的特点,适合于工程设计的要求。文章探讨采用遗传算法实现飞船返回轨道的一体化设计,并给出飞船返回轨道设计步骤。 相似文献
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文章对弹道-升力式载人飞船返回舱再入着陆力学环境及其乘员和舱载仪器设备的防护措施进行了理论分析和试验研究。适当的返回舱座椅安装角度有利于乘员承受再入过载。座椅缓冲系统是吸收着陆冲击能量、保护乘员最重要的环节,发挥返回舱结构缓冲吸能作用也是改善着陆冲击环境的有效措施。合理设计返回舱设备布局和安装形式可保护舱载设备免受着陆冲击损坏。防护措施的改进可有效保护乘员免受伤害,保证舱载仪器设备正常工作。 相似文献