Abstract: A static output feedback sliding mode controller is designed for helicopter based on linear perturbation model.A reference model is employed to guarentee satisfactory dynamic responses.The problem of designing sliding mode surface is resolved by solving a set of BLMIs using iterative LMI approach，which is equivalent to the existing conditions of sliding mode surface.The variable structure control law based on unit vector method is used for synthesizing the system.The linear feedback is introduced to the control law in order to guarentee that the linear control accords with the nominal system after the practical system settles in the sliding mode.

Key words: helicopter, variable structure control law, output feedback, Iterative Linear Matrix Inequality（ILMI）

摘要： 针对直升机的小扰动模型，设计了静态输出反馈滑模控制器（SOFSMC）。利用参考模型，实现了直升机的相关动态指标。针对滑模面的设计问题，将其等价地转化为一组双线性矩阵不等式（BLMI），并采用迭代线性矩阵不等式（ILMI）技术来求解。针对控制律的综合问题，给出了一种基于单位向量法的控制律，并通过引入线性反馈来保证系统进入滑动模态后线性控制部分与标称系统的线性控制部分的一致性。仿真结果验证了该方法的有效性。

关键词: 直升机, 变结构控制律, 输出反馈, 迭代线性矩阵不等式