含ESO的QTR无人机垂直起降模态分数阶滑模姿态控制

摘要

针对四倾转旋翼飞行器姿态控制系统复杂非线性、强耦合、多输入多输出、存在复合干扰等特点，提出了一种分数阶滑模控制的设计方法。利用分数阶微积分算子的积分权重随时间的推移逐渐减小的特性，柔化作用在被控系统上的能量，减小整数阶微积分滑模面的超调现象，设计了分数阶微积分滑模面。并针对传统幂次趋近律收敛时间长、速度慢、抖震严重等不足，提出了一种具有二阶滑模特性的新型快速趋近律。在此基础上采用扩张状态观测器在线对复合干扰进行估计和补偿。仿真结果表明，相比传统整数阶滑模控制，所提控制方案具有良好的控制性能。%For the attitude control of quad tilt rotor ( QTR) aircraft with complex nonlinear, strong coupling, multi⁃ple input and multiple output, unknown external disturbances, the method of fractional order sliding mode control is proposed. Using the characteristics of the gradually decrease over time of fractional calculus operator integral weight, reduced the overshoot phenomenon of the sliding mode surface of integer order calculus. In order to solve the problem of long convergence time and shake out serious of the traditional reaching law, put forward a new fast reaching law model with characteristics of second order sliding mode. Considering the existence of complex disturb⁃ances, the extended state observer is used to estimate and compensate the composite disturbance on line. By compa⁃ring with the traditional integer order sliding mode control, simulation experiment results show that the proposed control scheme has good control performance.