Gas metal arc welding (GMAW) processes are currently of great industrial importance, being used in the manufacture of the most varied components and metallic structures and in the recovery of a large ...number of damaged parts. In this work, a multi-objective heuristic technique namely the grasshopper optimization algorithm (MOGOA), is proposed in order to be used in a robust welding current and arc voltage control with a fractional order proportional integral-derivative (FOPID) controller with integer filter. The problem of setting the FFOPID parameters has been transformed into an optimization problem with an objective function based on time domain and solved with MOGOA. The proposed approach has been applied to a GMAW process. The performance of the newly designed FFOPID structure (GOAFFOPID) based on the proposed GOA was compared with the GA and PSO algorithms. The superiority, potential and robustness of the proposed approach were verified through nonlinear simulation study and some dynamic performance indexes.
This article introduces a robust optimal control strategy to improve the speed error-tracking and control capability of a permanent magnet DC Motor (PMDC) driven wire-feeder systems (WFSs) of gas ...metal arc welding (GMAW) process. The proposed speed controller employs an optimized fractional-order-proportional + integral + derivative (FOPID) regulator that serves to eliminate oscillations, overshoots, undershoots and steady state fluctuations of the PMDC motor and makes the wire-feeder unit (WFU) has fast and stable starting process as well as excellent dynamic characteristics. The fixed controller parameters are meta-heuristically selected via an ant colony optimization (ACO) algorithm. Numerical simulations are performed in MATLAB/SIMULINK environment and the performance of the proposed ACO-FOPID regulator is confirmed. The simulation results visibly present the considerable improvement rendered by the considered approach in the wire-feeder system's reference tracking performance, torque disturbance rejection capability, and transient recovery time.
a speed-controlled dc-motor chopper drive of wire- feed mechanism implemented by Arduino-Uno board is presented in this paper. This drive system is characterized as high static and viscous frictions ...load, even more it features a variable moment of inertia. Thus, the speed regulator with internal current loop should be carefully designed. Therefore, PI- speed and current regulators design should be fulfilled at limit values that wire-feed mechanism inertia can be taken to insure the stability. Finally, the obtained controllers are discretized and implemented. The experiment results exhibit sufficient agreement in term of transient response and stability which justifies the ability of introducing microcontroller-based Arduino in industrial applications.
Water scarcity is the first and most challenging crisis worldwide. Atmospheric water, also known as air humidity, is one of the most accessible resources and therefore could be used as a sustainable ...resource for water harvesting. There are some mechanisms for atmospheric water harvesting, including the following methods: vapor condensing, active cooling of the ambient air, and fog harvesting. The use of the Moisture Harvesting Index (MHI) for estimating water production and its energy requirements are demonstrated. Due to varying daily and seasonal meteorological conditions, the MHI shows considerable variability. There are different systems with specific functions to harvest water based on the methods and used materials in the process of atmospheric water generator (AWG) systems. AWGs are nowadays more effective as relative humidity and air temperature are increasing due to climate change.
In this study an improved control scheme for autonomous photovoltaic (PV) generator fed wire feeder unit (WFU) of arc welding machine using a brushless DC (BLDC) motor is developed. As power ...generated from PV energy systems always depends on varying weather conditions, to get maximum output power from PV generator at every insolation variation, Adaptive Neuro Fuzzy Inference System (ANFIS) based MPPT controller is combined with particle swarm optimization (PSO) algorithm to track the MPP of the PV generator. The suggested hybrid technique identifies and tracks the MPP and provides accurate and fast response of an autonomous PV wire feeder unit (PV-WFU). To maintain the welding wire speed constant under varying conditions, a fractional-order PI (FOPI) speed controller based on hysteresis current control (HCC) scheme is adopted to drive the BLDC motor of WFU. A MATLAB/SIMULINK model is developed for this purpose and results are presented. The simulations show that the proposed hybrid PSO-ANFIS based on MPPT controller has been able to control the PV output power around the maximum point at all weather condition scenarios. In addition, the proposed FOPI controller successfully tracked the welding wire speed for WFU over traditional PI controller.
The acetone extract of the roots of
Salvia jaminiana, containing the sterols campestanol, stigmasterol and sitosterol, and five known diterpenoids, ferruginol, cryptanol, 6,7-dehydroroyleanon, ...6-hydroxysalvinolone and microstegiol, remarkably inhibited the growth of
Bacillus subtilis,
Staphylococcus aureus ATCC 25923 and
Streptococcus α-hemolitic.
