Slosh Control Research Articles

Effect of the pore parameters of the perforated baffle on the control of liquid sloshing

The phenomenon of liquid sloshing inside a tank has a significant negative impact on the safety of the vessel. Installing perforated baffles is considered an effective means of mitigating liquid sloshing. This study investigated the influence of pore parameters on the anti-sloshing effectiveness of baffles. The simulations were performed using STAR-CCM+. In the numerical simulation of the tank sloshing, we have adjusted the factors in the k-ε model to obtain more approximate results compared to the experiments. By changing variables such as the porosity, degree of porosity, and pore distribution of the baffles, the results of the numerical simulations were compared to analyze their performance. Different combinations of porosity and porosity degree parameters have varying effects on sloshing factors such as the wave height, pressure, and rolling moment of the liquid tank. The perforated baffle performed well at restraining the slamming load. The findings also indicate that the effects of porosity are greater than those of the pore distribution. In most cases, an even pore distribution is more effective. These results can provide guidelines for the optimal design of vertical porous baffles.

Effect of Frequency Content of Seismic Excitation on Slosh Response of Liquid Tank with Baffle Plate

The violent dynamic behavior of liquid under horizontal excitation is a key factor that needs to be addressed in the seismic-resistant design of liquid tanks. Therefore, this study focuses on the slosh response of the liquid medium in a rectangular tank under Imperial Valley 1979, El Centro 1940 and Kobe 1995 ground motions of different frequency ranges. The ground motions records are selected based on the PGA/PGV ratio. For slosh control, a single vertical perforated baffle plate is used as an anti-slosh element with different configurations of perforations. Considering the free surface elevation as the major response parameter, the effect of percentage of perforation of the baffle plate, clear spacing of perforations and offset distance of the perforated plate are investigated by carrying out the pressure-based transient analysis using computational fluid dynamic (CFD). The optimum perforation varies from 10% to 17%, corresponding to the frequency of ground motion in the range of far-resonant to near-resonant conditions. Additionally, “rapid zone” ([Formula: see text]-zone) and “moderate zone” ([Formula: see text]-zone) are identified to pilot the positioning of the perforated baffle plate in liquid tanks. The perforated baffle plate with an optimum range of moderately spaced perforations positioned at the moderate zone of the tank effectively reduces the free surface elevation. Furthermore, the perforated baffle plate is more advantageous during violent sloshing under near-resonant conditions.

Magneto-active Slosh Control

The Magneto-active Slosh Control (MaSC) project seeks to demonstrate active slosh control in cylindrical propellant tanks by means of a thin, flexible metallic membrane that is acted on by a magnetic field in order to reposition itself to produce an optimized force on the surface of the liquid. Slosh is a destabilizing effect of engine burns and other orbital operations. The mitigation of slosh is a mission-critical effort in the aerospace industry. The overall objectives for the Magneto-active Slosh Control experiment are to demonstrate slosh control forces on liquid surfaces exerted by a high-permeability magnetic membrane in an external magnetic field, as well as develop active sensing and control of the membrane's position in microgravity environments.

Deep Reinforcement Learning based Super Twisting Controller for Liquid Slosh Control Problem

Deep Reinforcement Learning (DRL) based parameter optimization of super twisting control (STC) for the liquid slosh control problem in a moving vehicle is proposed in this paper. The slosh control problem, including the vehicle dynamics, represents an under-actuated nonlinear dynamical system. The slosh phenomenon is modeled by a simple pendulum on a cart and STC had been designed in the literature for the system when the vehicle motion is in a straight line. In this paper, a DRL framework is designed for the first time to tune the STC parameters in order to deliver near optimal performance. The effectiveness of this proposed learning-based STC for the slosh control problem is validated in a Python simulation environment and its performance compared to that of the existing STC design without the learning.

Numerical study of liquid sloshing in 3D LNG tanks with unequal baffle height allocation schemes

Tank sloshing is a hotspot issue in the design of a vessel. The liquid in a partially filled tank sloshes along with the ship. Except the negative effects to the stability of the ship, the sloshing phenomena may damage the wall of the tank due to the attacking pressure. Therefore, the control of the tank sloshing is one of the researches emphasizes. While the baffles in tanks have positive effect on the control of the tank sloshing, so we compare influence of different baffle factors, such as the number of baffles, the liquid rate, excitation frequency. Then compare the effect by investigating the wave height, spectrum, hydrodynamic force and the velocity vector. The simulation processes are executed in STAR-CCM+. In the numerical simulation of the tank sloshing, we obtained a deformation at the peak of the wave height by adjusting the factors in the k−ε model, which is more approximate to the experimental results. Moreover, in order to obtain the wave height through the direct measurement of the liquid height, we derive the relationship between the liquid height and the wave height. Finally, we proposed an unequal baffle height (UBH) allocation scheme. Then compared the performance of UBH scheme with the equal baffle height (EBH) scheme which has the same baffle number under the condition that the total height of all baffles is the same. The performance of different baffle height allocation schemes are compared by setting different baffle height gradient. Numerical simulation results showed that the allocation of the baffle height has effect on the control of tank sloshing. The UBH scheme with the proper baffle height gradient performs better than the EBH scheme when we take no account of the baffle strength.

Liquid slosh control by implementing model-free PID controller with derivative filter based on PSO

<span>Conventionally, the control of liquid slosh system is done based on model-based techniques that challenging to implement practically because of the chaotic motion of fluid in the container. The aim of this article is to develop the tuning technique for model-free PID with derivative filter (PIDF) parameters for liquid slosh suppression system based on particle swarm optimization (PSO). PSO algorithm is responsible to find the optimal values for PIDF parameters based on fitness functions which are Sum Squared Error (SSE) and Sum Absolute Error (SAE) of the cart position and liquid slosh angle response. The modelling of liquid slosh in lateral movement is considered to justify the design of control scheme. The PSO tuning method is compared by heuristic tuning method in order to show the effectiveness of the proposed tuning approach. The performance evaluations of the proposed tuning method are based on the ability of the tank to follow the input in horizontal motion and liquid slosh level reduction in time domain. Based on the simulation results, the suggested tuning method is capable to reduce the liquid slosh level in the same time produces fast input tracking of the tank without precisely model the chaotic motion of the fluid.</span>

Hydroelastic modeling and active control of transient sloshing in a three dimensional rectangular floating roof tank

Partly filled rectangular containers are widely used for liquid transportation and storage in many industrial and civil applications. Undesirable liquid sloshing in these structures can highly degrade their reliable and safe operations. This paper presents a rigorous 3D hydro-elasto-dynamic analysis for suppression of transient liquid sloshing in a rigid-walled rectangular parallelepiped container that is equipped with a smart piezo-sandwich free-floating rectangular panel. The problem formulation is based on the linear water wave theory, the thin piezo-sandwich floating plate model, the pertinent structure/liquid compatibility condition, and the active damping control strategy. The controller gain parameters are systematically tuned using a standard MOPSO algorithm with conflicting objective functions. The key hydro-electro-elastic response parameters are calculated and discussed for three different external excitations, namely, a bidirectional seismic event, an oblique planar base acceleration, and a distributed impulsive floating roof excitation. Effectiveness of proposed active floating panel control configuration in remarkable suppression of the main hydro-elastic parameters is established, essentially regardless of liquid depth and loading configuration. Limiting cases are considered and validity of model is demonstrated against available data as well as by comparison with the results of a general finite element package.

H-infinity controller with graphical LMI region profile for liquid slosh suppression

This paper presents a H-infinity synthesis with pole clustering based on LMI region schemes for liquid slosh control. Using LMI approach, the regional pole placement known as LMI region combined with design objective in H-infinity controller guarantee a fast input tracking capability and very minimal liquid slosh. A graphical profile of the transient response of liquid slosh suppression system with respect to pole placement is very useful in giving more flexibility to the researcher in choosing a specific LMI region. With the purpose to confirm the design of control scheme, a liquid slosh model is considered to represent the lateral slosh movement. Supremacy of the proposed approach is shown by comparing the results with hybrid model-free fuzzy-PID controller with derivative filter. The performance of the control schemes is examined in terms of time response specifications of lateral tank tracking capability and level of liquid slosh reduction.

Damping Control of Sloshing in Liquid Container in Cart With Active Vibration Reducer: The Case of a Curved Path on a Horizontal Plane

This paper proposes a control system for an active vibration reducer to damp sloshing in a liquid container transferred by a cart. The active vibration reducer is installed on the cart, and has a parallel linkage mechanism with six degrees of freedom. It tilts to horizontally shift the liquid container to damp the sloshing generated as the container is moved along a path. Only (1, 1)-mode sloshing is modeled as the dominant mode in the control system. The reducer is controlled by a frequency-dependent optimal servo system adapted to prevent the control system from destabilizing due to the unmodeled sloshing mode. The control gain in the optimal servo system is determined using a genetic algorithm (GA), where the amplitude of sloshing is considered for the fitness of the GA. The cart was driven along a curved path on a horizontal plane in an experiment to test the proposed control system, and exhibited satisfactory damping performance.

Active slosh control and damping - Simulation and experiment

Future reignitable cryogenic upper stages perform long ballistic coasting phases in earth orbit. During those coasting phases, the tanks are loaded with liquid propellants and propellant sloshing occurs due to external disturbances or attitude change maneuvers. The sloshing propellant motion induces reaction forces and torques acting on the space vehicle structure, e.g. rocket upper stages. To keep the upper stage at the desired target attitude, the guidance, navigation, and control (GNC) algorithm commands thruster firings to counter the fluid forces. At ArianeGroup (AG), the Final Phase Simulator FiPS aims at simulating the coupling between fluid mechanics, GNC, and rigid body dynamics. To validate the coupling of GNC with linear lateral water sloshing, on ground experiments at the German Aerospace Center's Hexapod sloshing facility were performed. It was demonstrated that the developed control algorithm is able to damp the linear lateral sloshing within 4 s. FiPS simulations of the open and closed loop sloshing experiments showed that the experimental forces are matched with an uncertainty of less then 5% for open loop phases. For closed-loop phases the simulations match the experimental damping intervals with an accuracy of better than 5% and the force amplitude with an accuracy of about 20%.

Propellant Slosh Force and Mass Measurement

We have used electrical capacitance tomography (ECT) to instrument a demonstration tank containing kerosene and have successfully demonstrated that ECT can, in real time, (i) measure propellant mass to better than 1% of total in a range of gravity fields, (ii) image propellant distribution, and (iii) accurately track propellant centre of mass (CoM). We have shown that the ability to track CoM enables the determination of slosh forces, and we argue that this will result in disruptive changes in a propellant tank design and use in a spacecraft. Ground testing together with real-time slosh force data will allow an improved tank design to minimize and mitigate slosh forces, while at the same time keeping the tank mass to a minimum. Fully instrumented Smart Tanks will be able to provide force vector inputs to a spacecraft inertial navigation system; this in turn will (i) eliminate or reduce navigational errors, (ii) reduce wait time for uncertain slosh settling, since actual slosh forces will be known, and (iii) simplify slosh control hardware, hence reducing overall mass. ECT may be well suited to space borne liquid measurement applications. Measurements are independent of and unaffected by orientation or levels of g. The electronics and sensor arrays can be low in mass, and critically, the technique does not dissipate heat into the propellant, which makes it intrinsically safe and suitable for cryogenic liquids. Because of the limitations of operating in earth-bound gravity, it has not been possible to check the exact numerical accuracy of the slosh force acting on the vessel. We are therefore in the process of undertaking a further project to (i) build a prototype integrated “Smart Tank for Space”, (ii) undertake slosh tests in zero or microgravity, (iii) develop the system for commercial ground testing, and (iv) qualify ECT for use in space.

Dynamics and Control of Three-Dimensional Slosh in a Moving Rectangular Liquid Container Undergoing Planar Excitations

While significant work has been directed at suppressing the 2-D slosh, less success has been achieved with reducing the 3-D slosh in a moving rectangular container. Control of the 3-D slosh in a moving rectangular liquid container is very challenging because there are two fundamental modes and an infinite number of high modes. The dynamics of the 3-D slosh in a moving rectangular container are derived. The theoretic analysis shows that both the two fundamental and high modes have large impacts on the sloshing dynamics. A command smoothing technique is designed to suppress slosh for the two fundamental and high modes. Comparing with the combined input shaper and the low-pass filter scheme, the presented smoother provides more robustness to variations in the sloshing frequency. Simulations over a large range of various working conditions and system parameters are conducted to analyze the liquid sloshing dynamics and the robustness of the method. Experimental results obtained from a moving rectangular liquid container validate the simulated sloshing dynamics behavior and the effectiveness of the method.

A robust control approach for suppression of container-slosh using output-feedback based on super-twisting algorithm

Slosh phenomena are being encountered in various fields leading to performance deterioration. The major challenges in slosh control are due to underactuated nature. Moreover, it is very difficult to measure the slosh angle, which poses additional challenge. In this paper, a control approach for container-slosh system is discussed using output-feedback. To make the controller robust and practically implementable higher order sliding mode (HOSM) scheme is used. Surface is a linear combination of displacement and velocity of the container. Control is developed using second-order sliding modes (SOSM) based on super-twisting algorithm. Closed-loop stability has been verified mathematically using Lyapunov approach. Finally, the performance of the controller is validated in simulations.

604 6自由度パラレルリンク型アクティブ吸振器付き搬送台車による液体タンクの制振搬送制御 : 規範モデル追従制御と最適サーボの併用

604 6自由度パラレルリンク型アクティブ吸振器付き搬送台車による液体タンクの制振搬送制御 : 規範モデル追従制御と最適サーボの併用

Estimation of Natural Frequency and Suppression Control of Sloshing during Ladle Transfer and Tilt Motion by Automatic Pouring Machine

Estimation of Natural Frequency and Suppression Control of Sloshing during Ladle Transfer and Tilt Motion by Automatic Pouring Machine

Design of the Flexible Container for Control of Sloshing

The inherent flexibility of a liquid container is usually treated as a problem since achieving a perfectly rigid container is practical impossibility. On the other hand container flexibility may be used as design parameter in control of free surface oscillations. Intentional container flexibility has been employed in this research to suppress excessive levels of liquid sloshing. This paper outlines numerical predictions for simulation of liquid sloshing in a flexible container and its design alternatives while maintaining effective control.

G101034 6自由度パラレルリンク型アクティブ吸振器付き搬送台車による液体タンクの制振搬送制御 : 高次モードスロッシングを励起させない制振制御([G101-03]機械力学・計測制御部門,一般セッション(3))

G101034 6自由度パラレルリンク型アクティブ吸振器付き搬送台車による液体タンクの制振搬送制御 : 高次モードスロッシングを励起させない制振制御([G101-03]機械力学・計測制御部門,一般セッション(3))

614 6自由度パラレルリンク型アクティブ吸振器付き搬送台車による液体タンクの制振搬送制御 : 高次モードスロッシングを対象とした曲線路走行

614 6自由度パラレルリンク型アクティブ吸振器付き搬送台車による液体タンクの制振搬送制御 : 高次モードスロッシングを対象とした曲線路走行

Nonlinear modeling and control of slosh in liquid container transfer via a PPR robot

This paper studies the point-to-point liquid container transfer control problem for a PPR robot. The robot manipulator is represented as three rigid links, and the liquid slosh dynamics are included using a multi-mass-spring model. It is assumed that two forces and a torque applied to the prismatic joints and the revolute joint, respectively, are available as control inputs. The objective is to control the robot end-effector movement while suppressing the sloshing modes. A nonlinear mathematical model that reflects all of these assumptions is first introduced. Then, Lyapunov-based feedback controllers are designed to achieve the control objective. Two cases are considered: partial-state feedback that does not use slosh state information and full-state feedback that uses both robot state and slosh state measurements or estimations. Computer simulations are included to illustrate the effectiveness of the proposed control laws.

Suppression Control of Sloshing in Ladle by Two-degree-of-freedom Control

Suppression Control of Sloshing in Ladle by Two-degree-of-freedom Control