Design of adaptive flight control law for center of gravity and mass variation and HIL real-time simulation verification

面向重心、质量变化的自适应飞行控制律设计与半物理实时仿真验证

¹ School of Automation, Northwestern Polytechnical University, Xi'an 710129, China
² Shaanxi Province Key Laboratory of Flight Control and Simulation Technology, Xi'an 710129, China

Received: 22 December 2021

Abstract

Considering the influence of the center of gravity (CG) and mass variations on flight dynamics, a nonlinear L1 adaptive control approach is presented in this paper and applied to design a flight controller to achieve the aim of improving the robustness of the flight system against sudden changes in the CG. Based on L1 adaptive control, this approach introduces a feedback linearization strategy to eliminate the known nonlinear dynamics of the aircraft and realize the rapid decoupling of the aircraft states. The nonlinear L1 adaptive control also addresses the problem of insufficient robustness in conventional L1 adaptive control due to overcoming its own known nonlinearities, and then improves the robustness to external disturbances. Additionally, the modified piecewise constant is employed to design the adaptive law to improve the estimation accuracy. Finally, the control performance and robustness of the designed flight control law are verified in the hardware in the loop (HIL) flight control semi-physical experimental platform. Experimental results indicate that the nonlinear L1 adaptive flight control law has strong robustness, which can effectively overcome the disturbance of the CG and mass sudden variations. Moreover, the designed controller takes into account the transient performance while ensuring the steady-state performance of the aircraft with CG change.

摘要

考虑到重心、质量变化对飞行器动态的影响, 提出一种非线性L1自适应控制方法, 并应用此方法设计飞行控制器, 达到提高飞控系统对重心、质量变化扰动鲁棒性的目标。该方法在L1自适应控制的基础上引入反馈线性化策略, 用于消除飞行器已知非线性动态, 并实现飞行器状态的快速解耦。提出的非线性L1自适应控制解决了常规L1自适应控制因克服自身已知非线性而导致鲁棒性不足的问题, 进而提高控制器对外部扰动的鲁棒性。此外, 应用改进的分段常数设计自适应律提高扰动的估计精度。在硬件在环的飞行控制半物理实验平台下验证所设计的飞行控制律的控制性能与鲁棒性。实验结果表明, 基于非线性L1自适应设计的飞行控制律具有强大的鲁棒性, 能够有效克服飞行过程中重心、质量突变对飞机的影响, 在保证飞机稳态性能的同时, 兼顾了飞机的瞬态性能。