Optimal Command Shaping Design for a Liquid Slosh Suppression in Overhead Crane Systems

In many industries, liquid container transport is carried out by an overhead traveling crane. The operation of crane transferring liquid slosh containers required both operator experience and an automated control system. The goal of this research is to move the liquid inside a container in a short time and less spill for process effectiveness and safety. For controller design, a nonlinear mathematical model is developed to represent the actual system. A cost-effective, smooth continuous command shaper is presented to suppress sloshing vibration. The designed shaper is a multisine-wave function with adjustable and independent time maneuvering used to design the acceleration profile. The coefficients that control the shaper profile are obtained by solving a nonlinear constrained optimization problem using particle swarm algorithm. Simulation and experimental comparative results proved that the proposed command shaper can reduce transient peak slosh amplitudes. Moreover, it can simultaneously cancel both residual sloshing vibrations and container oscillations at the end of the transportation process which cannot be achieved using conventional zero-vibration (ZV), zero-vibration derivative (ZVD), and jerk-limited shaper. Furthermore, sensitivity analysis demonstrates that the proposed command shaper is robust to model parameters variation such as liquid depth, suspension length, or moving distance of the trolley.

Modeling and adaptive robust wavelet control for a liquid container system under slosh and uncertainty

Liquid sloshing in moving or stationary containers and flexible uncertainty caused by the slosh are considered to be the most probable causing unexpected coupling effects on the dynamics of many systems such as aerospace, ground vehicles, and high speed industries arms. The coupling of dynamic liquid slosh in a container system with the uncertainty caused by the sensors or dampers is rare documented and this coupling can be considered as a highly nonlinear system. In this paper, an investigation is presented to demonstrate a new approach for enabling the reduction of the liquid slosh and uncertainty by implementing adaptive robust wavelet control technique. Starting by creating the mathematical dynamic model for the nonlinear slosh coupled by uncertainty, adaptive robust control based wavelet transform is applied for calculating optimal motion that minimize residual slosh and uncertainty. Subsequently the adaptive robust control based wavelet network approximation and the appropriate parameter algorithms for the container system with slosh and uncertainty are derived to achieve the feedback linearization, adaptive control, and H∞ tracking performance. The simulation results show that the effects of slosh errors and external uncertainty can be successfully attenuated within a desired attenuation level.

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>