Nonlinear Slosh Dynamics And Its Control In Rectangular Containers

The liquid sloshing will produce the force and action torque on the wall of the tank,which can obviously change the dynamic characteristics of the system,seriously affect the stability of the system structure and the stability of the movement,and destroy the mechanical structure;In this paper,we studied the dynamics and control of two-dimensional liquid nonlinear sloshing.Significant work has been focused on suppressing linear fluid slosh.However,little attention has been paid on vibration reduction for nonlinear slosh.Control of weakly nonlinear slosh in a moving liquid container is very challenging because of its complicated dynamics.Dynamical analysis of weakly nonlinear lateral slosh is derived.The even mode in the nonlinear slosh also has some impacts on the dynamics,which is different from the linear slosh.A new control method is presented to eliminate the weakly nonlinear slosh.The theoretic analyses show that the new method can provide robustness to large changes in sloshing frequency.Simulation over a large range of working conditions and system parameters are conducted to analyze the dynamics of weakly nonlinear lateral slosh and robustness of the presented method.Experimental results from a moving rectangular container validate the simulated sloshing dynamics behavior and the effectiveness of the method.Then we studied the dynamics and control of three-dimensional liquid nonlinear sloshing.The majority of previous works on slosh suppression have concentrated on the linear slosh.However,there are many cases when the slosh exhibits threedimensional weakly nonlinear dynamics.The coupling effect between the infinite modes along the transverse and longitudinal directions produces complex dynamic behavior,which is significant different from the linear slosh.Therefore,the manipulator task for the three-dimensional weakly nonlinear slosh can be more challenging because of the complicated nonlinear dynamics.A new method is designed for eliminating the weakly nonlinear slosh by smoothing the driving commands.Comparison between the new method and previously present method is also explored.Experimental results obtained from a moving rectangular container validate the dynamic effects and the effectiveness of the method.The thesis presented two kinds of control methods,designed based on the smoothing technique.The methods can suppress the infinite sloshing modes and they are open-loop control,low cost,simple design and easy engineering realization.The research results have important significance and the engineering realization value for the research of aircraft flight attitude control,canned production line,large-scale irrigation planning stability and safety.