Fast Model Predictive Control of the Nadir Singularity in Electro-Optic Systems
Fast Model Predictive Control of the Nadir Singularity in Electro-Optic Systems
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DOI：
10.2514/1.30762
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发表时间：
2009-04
影响因子：
2.6
通讯作者：
David Anderson;Meghan McGookin;N. Brignall
中科院分区：
文献类型：
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作者：
David Anderson;Meghan McGookin;N. Brignall
瞄准瞄准和视线稳定是所有机载光电设备的重要性能指标。在传统的控制理论术语中，定点任务是跟踪要求、eitherofadynamictargetorsomeotherspecialpointof兴趣和稳定性，指的是视线控制器的干扰抑制能力；典型的干扰是自身运动和承受摩擦的组合。指向和稳定任务之间的相对重要性取决于环境系统的密集操作；例如，long-rangetargetingrequiresprecisestabilization，瞄准线对于定向红外对抗系统来说是必不可少的[1]，尽管指向和稳定回路都应该针对所有系统进行优化。当主机平台受到地对空导弹(通常是肩射便携式防空导弹)的攻击时，就会发生DIRCM交战，当DIRCM系统将干扰信号定位到导弹导引头上时，DIRCM会被击败。显然，在整个超半球视场中，精确的目标跟踪是至关重要的，因为任何跟踪缺陷都肯定会被未来的导弹制导系统和战术所利用。考虑到全球恐怖主义对航空业的特殊威胁，未来的DIRCM系统应该是小巧、轻便、经济实惠的，用于商用飞机，这总是限制了可用于视线控制的轴的数量。至少需要两个轴才能达到完全的超半球形状。外框(OG)轴通常被约束为相对于平台z轴(通过方位角�)旋转，内框(IG)相对于OG y轴(通过仰角“)旋转。这如图1所示。当内外轴垂直时，视线可以定位到空间中的任何方向，因为IG和OG轴形成了理想的正交基。然而，当内框角度接近最低点(定义为”��90°“)时(即，视线变得与外框的旋转轴对齐)，指向系统经历了被称为框的自由度的损失
RECISION pointing and stabilization of the sightline are vital capabilities in all airborne electro-optic (EO) equipment. In traditional control theoryterminology,the pointingtask isatracking requirement,eitherofadynamictargetorsomeotherspecialpointof interest, and stabilization refers to the disturbance rejection capability of the sightline controller; typical disturbances are a combinationofownshipmotionandbearingfriction. Therelativeimportance between the pointing and stabilization tasks is a function of the intendedoperationoftheEOsystem;forexample,long-rangetargetingrequiresprecisestabilization,butanagilesightlineisessentialfor directed infrared countermeasures (DIRCM) systems [1], although both pointing and stabilization loops should be optimized for all systems. A DIRCM engagement occurs when the host platform is attacked by a surface-to-air missile, usually a shoulder-launched Man-Portable Air Defence missile, which is defeated when the DIRCM system positions a jamming signal onto the missile seeker. Obviously, accurate target tracking is essential over a full hyperhemispherical field of regard (FOR), as any tracking deficiencies are sure to be exploited by future missile guidance systems and tactics. Given the particular threat of global terrorism to the airline industry, future DIRCM systems should be small, lightweight, and costeffective for inclusion on commercial aircraft, which invariably limits the number of available axes for sightline control. A minimum of two axes are necessary to attain full hyperhemispherical FOR. The outer gimbal (OG) axis is usually constrained to rotate with respect to the platform z axis (through azimuth angle � ) and the inner gimbal (IG) with respect to the OG y axis (through elevation angle "). This is shown in Fig. 1. When the outerandinneraxesareorthogonal,thesightlinecanbepositionedto any orientation in space, as the IG and OG axes form an ideal orthogonal basis. However,whenthe innergimbal angleapproaches the nadir (defined as " �� 90 deg) (i.e., the sightline becomes aligned with the axis of rotation of the outer gimbal), the pointing system experiences the loss of a degree of freedom known as gimbal