Flight Control System Design And Engineering Implementation Of An Unmanned Helicopter

Due to the unique flight capabilities, unmanned helicopters(UHs) are widely used in military and civilian fields. However, UHs are multi-variable, highly nonlinear, strong coupling and complex systems, which exacerbates the problem of a high-performance flight control system design. This paper presents a new adaptive attitude tracking control method with a reference model and a tracking model. A novel flight control hardware platform with double CPUs(DSP and XE167) is designed, based on which the conventional control method and the adaptive control method are comparatively tested. The superiority of the proposed adaptive control method is then verified.First of all, according to the principles of aerodynamics and kinematics, the nonlinear mathematical model of the chosen UH is developed by using the independent-component modeling method. The linear mathematical model is then obtained by using a small perturbation method. The coupling characteristics among axes are analyzed and demonstrated finally.Secondly, the decoupling flight control system is developed by using the invariance dynamic decoupling method. The attitude and position control of the UH is then designed based on the conventional control method, which is verified by a series of hardware-in-loop(HIL) tests.Thirdly, considering the adverse effect of measurement noises, the coupling among axes, trim errors and the uncertainties of aerodynamic parameters on the control quality, a new adaptive attitude tracking control method with double models is proposed. The convergence of the adjustable parameters is analyzed. Moreover, a modified controller with variable gain elements is designed to further reduce the adverse effect of measurement noises on the adjustable system output in the later stage of the adaptive learning process. A series of HIL tests have verified the proposed adaptive control schemes.Finally, A novel flight control hardware platform with good portability and high compatibility is designed based on DSP and XE167, thus realizing the separation of the data process and the calculation of flight control laws. Based on the hardware platform, the conventional control method and the proposed adaptive control method are comparatively tested. The test results have demonstrated that the proposed adaptive control method has superior control.