Slosh Suppression For Infinite Modes By Using Smoothing Technique

Slosh in a container may have significant influence on the whole system. Theinteraction of the sloshing dynamics with the container may lead to the instabilities anddestroy the mechanical structure in many cases. The control of the sloshing is verychallenging because the sloshing dynamics is very complicated and the states variablesare difficult to measure. Therefore, it is critical to develop a control scheme which caneffectively suppress slosh to maintain safe operations. This thesis studies the sloshingdynamics and control of2D linear sloshing,3D linear sloshing and2D nonlinear sloshingrespectively. The main contributions can be divided into three parts:This thesis presents two new methods which can suppress slosh for infinite modes.Previous study ignored the effects of the high sloshing modes. This study investigates theimpacts of the high sloshing modes to the whole system dynamics and develops two newmethods which can effectively suppress infinite sloshing modes. The first method iscommand smoothing to eliminate slosh by using the first-mode frequency. The secondone is a combined input-shaping and command-smoothing architecture. The input shaperreduces slosh for the first mode, while the command smoother suppress slosh for the thirdand higher modes. Simulated and experimental results validated the effectiveness of themethods.This thesis firstly studies the dynamics and control of3D sloshing in a movingrectangular container undergoing planar excitations. There are two fundamental modesand infinite high modes. A command smoothing technique is designed to suppress sloshfor the two fundamental and high modes. The technique suppresses the vibration at themodel frequency to a tolerable level and limits the vibration at the two amendingfrequencies to zero. Simulations and experimental results validated the sloshing dynamicsbehavior and the robustness of the method.This thesis addresses the nonlinear two dimensional slosh in a rectangular container.Control of the large amplitude sloshing become more challenging because both the evenand odd modes have effects on the whole sloshing dynamics. A controller is designedinvolving the effects of the even sloshing modes and the control of the transient slosh.Experimental results obtained from a moving liquid container demonstrated that themethod could effectively control the transient and residual slosh. The thesis presents four control schemes for the control of sloshing based on thesmoothing technique. All the methods can suppress infinite sloshing modes underopen-loop control. The controllers are easy to design, implement. The controller caneffective suppress both the transient and residual sloshing. The results of the study havegreat meaning on the research of the driving stability of the large tank truck and thecontrol of spacecraft.