基于飞行品质评估的无人直升机鲁棒控制器设计

Unmanned Helicopter Robust Controller Design Based on Aircraft Flying Qualities Evaluation

提出了一种改进的无人直升机H∞回路成形鲁棒控制器设计方法。首先将系统辨识技术引入到无人直升机高带宽控制器设计,根据飞行扫频数据,得到包含直升机动力学模型耦合特性的非参数频率响应,依据频率响应拟合待辨识模型得到无人直升机高精度的飞行动力学模型。然后根据该模型,采用改进的H∞回路成形方法设计了无人直升机内回路控制器,针对H∞回路成形方法中权值矩阵选取困难的问题,利用了最大右约数(GCRD)方法以实现实际系统和期望系统的传递函数矩阵之间的转换。与传统的对角型权值矩阵相比,使用此方法成形后的系统具有更宽的鲁棒稳定裕度,系统的解耦性和频带也显著提高,而且可以大大降低设计人员选取权值矩阵的复杂性和盲目性。通过仿真验证,所设计的无人直升机系统的飞行品质满足军用标准ADS-33E中一级区域的要求。

A robust automatic flight control system is designed for a small scale unmanned helicopter in this paper. We first apply system identification to the design of a high-bandwidth controller for robotic helicopters. The overall concept is to ex- tract a complete set of non-parametric input-to-output frequency responses that fully characterize the coupled helicopter dy- namics, and then apply a nonlinear search algorithm for a linear high-fidelity simulation model that matches the frequency re- sponse data set. The H~ loop-shaping method is used to design the inner loop of the unmanned helicopter based on the iden- tified model. The greatest common right divisors （GCRD） method is employed to move the transfer function matrix from the real system to the target system, which is a very useful way to solve the difficulties in choosing a proper weighting matrix in H~ loop-shaping. Compared with the traditional method, the system using the new method exhibits a larger robust stability margin, and the decoupling and the bandwidth of the system are also improved considerably. Furthermore, it reduces the complexity and blindness for the designer to find the proper weighting matrix. The simulation results prove that the unmanned helicopter system achieves a top level control performance that conforms relevant requirements in military standards ADS-33E.