基于干扰观测器的三自由度模型直升机控制技术

发布时间：2018-08-29 10:59

【摘要】：直升机的飞行控制系统属于典型的多输入多输出(Multi-input and Multi-output,MIMO)系统,具有较强的通道耦合和非线性特性,是控制工程领域较为复杂的被控对象。三自由度(Three Degree Of Freedom,3DOF)模型直升机作为一个构造简单且成本低廉的实验装置,可用于验证各种线性和非线性控制方法,为直升机飞行控制方法的研究与开发提供指导作用。论文以固高科技有限公司研制的三自由度模型直升机为实验平台,针对存在外界未知干扰、建模不确定、输入饱和以及输出受限的三自由度模型直升机控制问题,研究了基于观测器的鲁棒控制方法。主要研究内容如下:首先,根据3DOF模型直升机的运动特点,研究了3DOF模型直升机的非线性数学模型,并在平衡状态进行线性化,给出了线性运动方程。然后,针对存在外界干扰的3DOF模型直升机线性模型,设计了基于干扰观测器的广义比例积分(Generalized Proportional Integral,GPI)控制器。所设计的干扰观测器能有效估计外界干扰;控制器的设计简单易行,控制参数可直接通过极点配置的方法获得。数值仿真结果表明,所设计的控制器在系统存在外界干扰情况下具有良好的跟踪性和鲁棒性。实验结果验证了所设计的GPI控制器比传统的比例积分微分(Proportion-Integral-Derivative,PID)控制器具有更好的跟踪性能,并能有效解决传统PID控制器中由微分项引入的噪声问题。其次,研究了一类具有外界未知干扰和建模不确定非线性系统的反演控制方法,并应用于3DOF模型直升机的运动控制。设计干扰观测器估计系统的外界未知干扰和建模不确定,设计反演控制律实现姿态的跟踪控制。利用Lyapunov方法证明了闭环系统的稳定性,并将该方法应用于俯仰通道的运动控制,仿真结果表明,在系统存在外界未知干扰和建模不确定情况下,所设计的控制器仍能保证俯仰通道具有良好的跟踪性能。实验结果验证了所设计的控制器使俯仰通道具有良好的跟踪性能。接着,考虑存在外界未知干扰和建模不确定的3DOF模型直升机非线性模型的三轴运动控制问题,研究了一种基于增广状态观测器的反演控制方法。将整个系统分成两个子系统,设计增广状态观测器有效估计未知状态、外界未知干扰和建模不确定;将滚转角作为偏航通道的虚拟控制输入,设计辅助系统,有效补偿偏航通道输入饱和的影响,并利用Lyapunov方法证明了闭环系统的稳定性。仿真结果表明,在系统存在外界未知干扰及建模不确定的情况下,整个闭环控制系统可以得到满意的跟踪性能。最后,针对3DOF模型直升机存在外界未知干扰、建模不确定、输入饱和和输出受限综合影响下的运动控制问题,设计了基于观测器的反演控制器。采用增广状态观测器处理系统的外界未知干扰、建模不确定和未知状态量;构造辅助系统解决电机饱和受限的影响;利用界限Lyapunov函数(Barrier Lyapunov Function,BLF)处理系统的输出受限问题,用Lyapunov方法证明了闭环系统的稳定性。仿真结果表明,在外界未知干扰、建模不确定、输入饱和及输出受限的综合影响下,所设计的控制器能保证整个闭环控制系统得到满意的控制效果。
[Abstract]:The helicopter flight control system is a typical multi-input and multi-output (MIMO) system. It has strong channel coupling and nonlinear characteristics. It is a more complex controlled object in the control engineering field. The experimental device can be used to verify all kinds of linear and nonlinear control methods and provide guidance for the research and development of helicopter flight control methods.In this paper, a three-degree-of-freedom model helicopter developed by Gu Hi-tech Co., Ltd. is used as the experimental platform, aiming at unknown external disturbances, modeling uncertainty, input saturation and output constraints. The main research contents are as follows: Firstly, according to the motion characteristics of the 3DOF model helicopter, the nonlinear mathematical model of the 3DOF model helicopter is studied, and the linear motion equation is obtained by linearization in the equilibrium state. A generalized proportional integral (GPI) controller based on disturbance observer is designed for a 3 DOF model helicopter with disturbance. The disturbance observer can effectively estimate the external disturbance. The design of the controller is simple and feasible, and the control parameters can be obtained directly by pole assignment. The results show that the designed controller has good tracking performance and robustness in the presence of external disturbances. The experimental results show that the designed GPI controller has better tracking performance than the traditional Proportion-Integral-Derivative (PID) controller and can effectively solve the problem of derivative in the traditional PID controller. Secondly, the inverse control method for a class of nonlinear systems with unknown disturbances and model uncertainties is studied and applied to the motion control of a 3D OF model helicopter. The Lyapunov method is used to prove the stability of the closed-loop system and the method is applied to the motion control of the pitch channel. The simulation results show that the controller can still guarantee the good tracking performance of the pitch channel in the presence of unknown disturbances and uncertainties. Secondly, considering the three-axis motion control problem of a nonlinear model helicopter with unknown disturbances and uncertainties, an augmented state observer based inverse control method is proposed. The whole system is divided into two subsystems and the augmented state observer is designed. The roll angle is used as the virtual control input of the yaw channel, and the auxiliary system is designed to compensate effectively the influence of input saturation of the yaw channel. The stability of the closed-loop system is proved by Lyapunov method. The simulation results show that the system has unknown external disturbances and the modeling is not correct. Finally, an observer-based inverse controller is designed for the motion control problem of a 3D OF model helicopter with unknown disturbances, uncertain modeling, input saturation and output constraints. The augmented state observer is used to process the system. The stability of the closed-loop system is proved by Lyapunov method. The simulation results show that the model is not established in the presence of unknown disturbances. It is determined that under the combined influence of input saturation and output constraints, the designed controller can ensure the satisfactory control effect of the whole closed-loop control system.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：V275.1;V249.1

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