增益调度自动驾驶仪结构特点与变轨迹飞行控制

Structural characteristics of gain scheduling autopilot for transfer trajectory control

构建了增益调度三回路自动驾驶仪系统来实现导弹实时变轨迹飞行,并对其结构原理、反馈量获取、控制性能及变轨飞行能力进行了研究。应用状态反馈原理和极点配置法建立了导弹纵向通道飞行控制数学模型;分析了弹体速度、动压和舵效率等状态参量对经典三回路自动驾驶仪控制指令的影响;根据增益调度理论,在自动驾驶仪中引入速度比、动压比及舵效率比等参数修正系统非线性,提出实际飞行过程中反馈量的获取方法。最后,分析了速率、复合稳定回路及过载回路的鲁棒稳定性。飞行试验表明:对大气密度、温度等数据的获取精度分别优于1.7%与3.0%;半物理实验表明:变轨弹道速度变化达到20.6%时,截止频率、加速度稳定增益和相角裕度分别由41.78rad/s、0.87、78.19°变为41.71rad/s、0.88和72.5°,相角裕度仍高于基准弹道最小值71.46°;动压变化77.6%时,自动驾驶仪仍保持了较好控制特性。实验结果表明,构建的增益调度三回路自动驾驶仪系统基本满足导弹实时变轨飞行的要求。

A gain scheduling three-loop autopilot was set up to realize the real-time change flight trajectory of a missile, and its structure characteristics, feedback parameter acquiring, control performance and the transfer flight ability were researched. With.the principle of state feedback and the pole assignment, a missile longitudinal flight control mathematical model was established, then the influence of the missile velocity, dynamic pressure and the elevator efficiency on the control instruction were analyzed in a typical three-loop autopilot. Combing with gain scheduling theory, the variables of velocity ratio, dynamic pressure ratio and elevator efficiency ratio were induced to correct the system nonlinearity, and the method to get feedback parameters was derived. In the end, three-loop robust stability was also analyzed. The comparison of the calculation results and the flight test data shows that the measuring accuracy of atmospheric density and atmospheric temperature is better than 1.7% and 3.0%, respectively, and the semi-physical simulation experiments prove that when the velocity changes to 20.6% in the variable trajectory, the cut-off frequency, overload steady-state gain and the phase margin are changed from 41.78 rad/s, 0.87, 78.19% to 41.71 rad/s, 0.88 and 72.5%, respectively. Moreover, the phase margin is also larger 71.46% than the minimum of basic trajectory, and the autopilot still keeps a good control characteristic when the dynamic pressure changes 77. 6%. These results prove that the gain scheduling three-loop autopilot meets the requirement of missiles for real-time transfer trajectory flight control.