Phase compensation of rate limiters in unstable aircraft
Phase compensation of rate limiters in unstable aircraft
复制标题
不稳定飞机中速率限制器的相位补偿
DOI：
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复制
发表时间：
1996
期刊：
影响因子：
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通讯作者：
K. Stahl
中科院分区：
文献类型：
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作者：
L. Rundqwist;K. Stahl
对于现代的气动不稳定的战斗机，如JAS 39鹰狮，飞行控制系统通常提供45/spl度/相位裕度。因此，控制面的速率限制，这可能会导致大的相移，是一个重要的问题。软件速率限制器被放置在控制伺服命令上，以防止液压伺服速率限制。当速率限制器饱和时，相移会大大降低闭环系统的稳定裕度，并增加驾驶员诱发振荡（PIO）的风险。本文提出了一种新的速率限制器相移补偿方法。与早期的相位补偿方法相比，该方法使用反馈而不是逻辑或前馈。讨论了该方法的开环和闭环特性。该方法给出了一个急剧改善的稳定性裕度和减少PIO的趋势。
For a modern aerodynamically unstable fighter, like the JAS 39 Gripen, the flight control system typically provides 45/spl deg/ phase margin. Therefore rate limiting of control surfaces, which may cause large phase shifts, is an important issue. Software rate limiters are placed on the control servo commands in order to prevent the hydraulic servos from rate limiting. When a rate limiter is saturated, the phase shift drastically reduces the stability margins of the closed loop and increases the risk for pilot-induced oscillation (PIO). This paper describes a novel method for compensating the phase shift of a rate limiter. In contrast to earlier phase compensation methods, this method uses feedback instead of logic or feedforward. Open loop and closed loop properties of the method are discussed. The method gives a drastic improvement on stability margins and reduces PIO tendencies.