Study On Laree Aircratf Touching Down Safely Using3-axis Positioners For Attitude Adjustment

In the posture adjustment accuracy aspect of the large aircraft assembly using traditional fixed-frame meets great difficulties. Using the experiences of the aviation industry by the developed countries for reference, in the wing-body docking of a large aircraft assembly project, Zhejiang University applies multiple3-axis NC positioners to collaborate motion control, achieve digital, automatic docking of the large aircraft wing-body. Based on the project as research background, this thesis conducts analysis and research aiming to the slip problem when the large aircraft slides off the frame from the3-axis positioners after the wing-body docking assembly, provides technical support for the aircraft safely sliding off the frame.Firstly, the posture adjustment object and the posture adjustment system based on four3-axis NC positioners are described in detail in the thesis, in particular, the connection structure between the posture adjustment object and the3-axis NC positioners are pointed out. And the trajectory planning method for the posture adjustment system is described, provides basis for the analysis and design of the posture adjustment system.In accordance with the process of aircraft sliding off the frame, aiming at two conditions of the nose landing gear landing first or the main landing gears landing first, the thesis conducts the stress analysis to the posture adjustment system in detail, obtain the slip conditions of the craft ball-heads in the ball-nests of the3-axis NC positioner.To ensure the aircraft sliding off the frame in safe and avoid the slippage problem, stress measuring devices are introduced to the3-axis NC positioners. A decision-maker is imported on the foundation of the original posture adjustment motion control system, and the pressure data of the four3-axis NC positioners are basis for decision, then introduce rotary motion in the foundation of vertical drop, realize the large aircraft’s safely sliding off the frame. The actual system sliding off the frame process verifies the validity of the proposed method in the thesis.