基于离散采样模型的三自由度双旋翼直升机的控制器设计

Controller Design of a 3-DOF Tandem-Rotor Model Helicopter Based on Discretized Sampling Plant

三自由度纵列式双旋翼直升机模型是动力学系统研究中的一类重要实验对象,也是研究直升机飞行控制技术的平台.文章首先针对非线性三自由度纵列式直升机模型的系统描述,在其标准形描述和一般采样保持条件下,导出了比经典的Euler模型更精确的非线性近似离散时间模型,并进一步计算可得出,它们的近似离散模型的局部截断误差和全局截断误差分别为T5和T2,其中T为采样周期.其次,文章对非线性三自由度双旋翼直升机进行了系统辨识及其相应的简单讨论.最后,在导出的近似直升机离散采样模型的基础上,对非线性三自由度双旋翼直升机,文章给出了连续时间输入控制设计和李雅普诺夫再设计两种方法来开展对比研究,并通过实例表明李雅普诺夫再设计可增强系统的控制性能.

The paper derives an approximate discrete-time model for a nonlinear 3-DOF tandem-rotor model helicopter in the case of the ordinary input and hold,such as zero-order hold,which is accurate to some order in the sampling periods.More importantly,the proposed model is more accurate than the classic Euler approximation.We also show how a particular strategy can be used to approximate the system output and its derivatives in such a way to obtain a local truncation error and a global truncation error,between the output of the resulting sampled-data model and the true continuous-time system output,of order and,respectively,where is the sampling period.Furthermore,we also explore the implications of these results in nonlinear system identification,which the corresponding discussion has been obtained.Finally,these two design methods,such as emulation input and Lyapunov redesign,have been considered for a nonlinear 3-DOF tandem-rotor model helicopter.It is shown that the Lyapunov redesign implementation model can achieve a better control performance.