Abstract: In order to realize high precision position control of gas rudder， a high-order nonlinear extended state observer was designed for precise closed-loop control of the steering gear position system. By combining the parameter perturbation coupling term with the external perturbation term into a new state variable， the original third-order position system was extended to a fourth-order control system. The sliding mode variable structure controller was used to control the observational results of the state observer， so that the steering angle reached the predetermined value. The traditional PID control and the designed high-order nonlinear extended state observer were used to simulate the actuator control system respectively to verify the response and stability performance of the designed controller. The results show that compared with the traditional PID controller， the designed high-order nonlinear extended state controller has higher tracking accuracy and faster response performance. Its response time is less than 0.1s， which improves about 0.7s， and the control system has no overshoot. The controller has better robustness and anti-interference. Thus it can better realize position control of the whole servo system.

Key words: Gas rudder;High-order nonlinear extended state observer;Position control;Variable structure controller;Brushless DC motor

摘要： 为了实现对燃气舵舵片的高精度位置控制，设计了高阶非线性扩张状态观测器对舵机位置系统进行精确闭环控制。通过将参数摄动耦合项和外界扰动项合并为一个新的状态量，将原有三阶位置系统扩张为四阶控制系统。采用滑模变结构控制器对状态观测器观测结果进行控制，使舵机偏转角度达到预定值。分别采用传统PID控制和所设计的高阶非线性扩张状态观测器对舵机控制系统进行仿真，来验证所设计的控制器的响应性能和稳定性能。结果表明：相比于传统的PID控制器，所设计的高阶非线性扩张状态控制器具有更高的跟踪精度和更快的响应性能，其响应时间在0.1s以内，提升了约0.7s，且该控制系统无超调量的产生。该控制器在鲁棒性、抗干扰性上体现出更好的特点，因此可以更好地实现整体伺服系统的位置控制。

关键词: 燃气舵;高阶非线性扩张状态观测器;位置控制;变结构控制器;无刷直流电机