Research Of Stability For Tractor-airplane System On Ship

The movement of airplane on deck is similar with it is on ground,they are both finishied by the airplane-tractor.On variable sea states the dynamic characteristic and stability of traction system driving on deck affect the deck operational security and operational condition directly.At first,a time-varying nonlinear dynamic model on deck is built on the base of multi-body dynamics theory and automobile dynamics theory.In the model the coupling relationship between the swaying ship and traction system is described,the influences of deck motion on traction system longitudinal force,lateral force,and tire force are considered,and the nonlinear relation at articulated point is analyzed.The established system dynamics model provides a basis for the investigation on driving stability of traction system.The straight line moving stability is studied.Based on the Floquet theory coped with periodic coefficient motion equations,the perturbation equation of system motion stability is evolved,and the straight line moving stability criterion is advanced.The critical velocity on different sea states is obtained,and the impact of tire cornering stiffness,airplane type and other structure parameters on system stability are discussed.The turning moving and turning braking stability of the traction system on swaying deck are studied.On different sea states and different turning angle,steady state response and transient state response characteristics of traction system on deck are investigated by simulation test and the boundary value of stable turning is obtained.By proposing the tractor braking force and optimal braking force allocation,the test strategy of the traction system curve line braking stability is devised.On various sea states the criticual braking force at different moments is revealed,by considering ship motion,braking force,movement time and adhesion coefficient as test parameters.A new control strategy for traction system stability is proposed in this work,by taking the tractor yaw angular velocity and relative yaw angular velocity feedback as the basic control logic.The control model of traction system is developed,by introducing the second order steering subsystem.Considering the effect of uncertain factors,the stability control alogtithm of traction system is exploited founded on backstepping variable structure control method which deals with nonlinear system.A control mode of the rear wheel active steering and front wheel compensatory steering is proposed to improve the handling stability of traction system and enhance the control sence of the tractor driver.The virtural experiment platform of tractor-airplane system on deck is carried out.On the base of establishing the vivid tractor system virtual model and virtual environment,the traction system and the ship can be real-time drived by the mathematic model and make the researcher have better immersion feeling.By the graphical user interface development environment,the test data and system parameters are initialized,and the experimental result curves are outputted.