基于系统非线性因素的阵风载荷减缓技术研究

Approach of Gust Load Alleviation Based on System Nonlinearity

摘要:

随着大型客机电传飞控的引入,系统非线性问题逐渐突显。对于阵风载荷减缓系统而言,非线性因素往往会严重影响阵风减缓效果。采用有限元和偶极子网格方法建立气动弹性模型,并分析其实际工程中主要的系统非线性因素,包括饱和、速率限制与延迟。其次,根据机载设备探测的阵风信息,以翼尖加速度、翼根剪力和弯矩作为阵风减缓指标,设计了阵风预测以及自适应前馈控制方案,从而弥补传统反馈控制中的不足性。最后,针对三种系统要求指标,分别与传统反馈控制进行减缓效率的对比分析。研究结果表明,系统的非线性因素对阵风减缓效果具有重大影响,且利用前方阵风探测信息设计的自适应前馈控制方案具备更好的阵风减缓效果。

Abstract:

With the introduction of fly by wire flight control for the large passenger aircraft, the nonlinear problem of the system becomes more and more prominent. For the gust load alleviation system (GLAS), nonlinear factors affect seriously the effect of gust alleviation. In this paper, the aeroelastic model is established by finite element method and dipole grid method. In addition, the paper analyzes the main nonlinear factors in practical engineering, including saturation, rate limitation and delay. Secondly, according to the gust information detected by airborne equipment, the gust prediction and adaptive feedforward control scheme are designed with the acceleration of wingtip, the shear and bending moment of wingroot response as the gust alleviation index, so as to make up for the shortcomings of traditional feedback control. Finally, aiming at the three kinds of system requirements, the paper compares and analyzes the alleviation efficiency with the traditional feedback control. The results show that the nonlinear factors of the system have a significant impact on the effect of gust alleviation. Moreover, the adaptive feedforward control scheme designed by using the front gust detection information has better gust alleviation effect.