三自由度直升机基于无模型自适应的姿态控制

In this paper, an improvement to model free adaptive control (MFAC) method is proposed for attitude control system of a 3-DOF helicopter. MFAC is a data-driven control method and generates the control signals based on the input and output data, not relying on the system mathematical model. The existing MFAC methods based on the compact form dynamic linearized data model require the system to satisfy four assumptions, however, this paper demonstrates that the 3-DOF helicopter attitude control system satisfies all other assumptions except for Assumption 4 (the corresponding controlled system output should be non-decreasing when the control input increases). Hence for the attitude control system of a 3-DOF helicopter, following improvements are made to the existing MFAC methods: i) A new output is defined as a linear combination of angle and angular velocity, and it has been proved that the redefined output satisfies Assumption 4; ii) It is proved that the linear parameter in the redefined output influences the performance of closed-loop system; iii) The input differentiation term is added to change the eigenvalue distribution of the closed-loop system and then improve the system performance. Finally, simulations as well as experiments are conducted to verify the effectiveness of the proposed scheme, respectively.