Antidisturbance Control for a Suspension Cable System of Helicopter Subject to Input Nonlinearities
研究了直升机悬挂缆绳的振动抑制问题，设计了非线性干扰观测器和边界控制器，使缆绳振动幅度最终有界并收敛到零附近。
In this paper, the suppressing problem of the cable's vibration is studied for a suspension cable system of helicopter with disturbances. The Hamilton's principle is applied to obtain a distributed parameter system of the suspension cable system which includes one partial differential equation and two ordinary differential equations. Two nonlinear disturbance observers are developed to compensate the effect of boundary disturbances. The auxiliary systems are designed to eliminate the effects of input nonlinearities. Based on the designed disturbance observer and auxiliary systems, two boundary controllers are designed at the top and bottom boundaries of the suspension cable. Under the proposed controllers, the amplitude of oscillation is proven to be uniformly ultimately bounded and converges to a small neighborhood of zero by selecting proper design parameters of the antidisturbance control scheme for the suspension cable system. Meanwhile, some sufficient conditions are provided to guarantee the effectiveness of the developed control law. Finally, simulation results show that the controllers developed in this paper work well in handling disturbances for the suspension cable system of helicopter.