三自由度实验室直升机模型是典型的高阶多输入输出系统,具有较强的通道耦合和非线性特性,其俯仰、倾斜和旋转三轴运动方程,能够部分模拟实际直升机的飞行特性,是控制理论教学和研究的有力工具。采用基于内模原理的无静差跟踪控制方法设计能够同时实现扰动抑制和鲁棒跟踪的无静差跟踪控制器,应用LQR方法设计系统状态反馈增益,将设计的线性解耦控制器应用到原非线性耦合模型上,计算机仿真和实时实验结果表明能够很好的实现轨迹跟踪控制。
The 3 degrees of freedom (3-DOF) laboratory helicopter is a typical multi-input multi-output system with high-order. It has strong channel coupling and high nonlinearity. The motion equations of its three axes in elevation, pitch, and travel can be used to simulate the dynamics of real helicopter. Since the helicopter was always subject to uncertainties and disturbances during flight, the internal model, which was the common unstable model of the reference input and the disturbance, was embedded into the servo compensator to realize disturbance rejection and robust tracking. The method of Linear Quadratic Regulator (LQR) was applied to obtain the gain of the state feedback for the system. Computer simulation results and real-time control experiment demonstrate the validity of the proposed method in no-steady-state error tracking control of the 3-DOF helicopter system.