128 research outputs found
Wear Measuring and Wear Modelling Based on Archard, ASTM, and Neural Network Models
No full textThe wear measuring and wear modelling are a fundamental issue in the industrial field, mainly correlated to the economy and safety. Therefore, there is a need to study the wear measurements and wear estimation. Pin-on-disc test is the most common test which is used to study the wear behaviour. In this paper, the pin-on-disc (AEROTECH UNIDEX 11) is used for the investigation of the effects of normal load and hardness of material on the wear under dry and sliding conditions. In the pin-on-disc rig, two specimens were used; one, a pin which is made of steel with a tip, is positioned perpendicular to the disc, where the disc is made of aluminum. The pin wear and disc wear were measured by using the following instruments: The Talysurf instrument, a digital microscope, and the alicona instrument; where the Talysurf profilometer was used to measure the pin/disc wear scar depth, a digital microscope was used to measure the diameter and width of wear scar, and the alicona was used to measure the pin wear and disc wear. After that, the Archard model, American Society for Testing and Materials model (ASTM), and neural network model were used for pin/disc wear modelling. Simulation results are implemented by using the Matlab program. This paper focuses on how the alicona can be considered as a powerful tool for wear measurements and how the neural network is an effective algorithm for wear estimation
Online Interactive Module for Teaching a Computer Programming Course
No full textAbstract: Teaching computing courses is a major challenge for the majority of lecturers in Libyan Higher Education institutions. These courses contain numerous abstract concepts that cannot be easily explained using traditional educational methods. The main aim of this article is to present a conceptual framework for laboratory-based learning designed to teach a computer programming module with the help of an e-learning package. The framework could be used for a single module or one of several modules with a specific aim. The framework should be useful for designers of online learning modules and teachers who are interested in the design of online courses on the Internet. The proposed framework will enable the current generation of students to be better prepared for a workplace where computers, the Internet and related technologies are becoming increasingly ubiquitous
Energy Optimisation of Sensorless Induction Motor Drives Using a Novel Robust-Adaptive Flux Simulator
No full textModern drive systems should have improved reliability and one solution is the reduction or elimination of the number of speed sensors while maximizing the efficiency of motor and drive systems. The paper presents the development of a novel robust-adaptive-flux simulator which is used for the energy optimisation of sensorless induction motor drives. The closed loop system contains a predictive current controller and an observer which is robust against parameters variation. The estimated values of the rotor magnetic flux are used to determine the motor core losses by the robust-adaptive observer. Particle Swarm Optimisation (PSO) algorithm is used for the optimization of rotor speed so the motor losses are minimized and so the motor efficiency is increased. The simulated results show that the proposed sensorless control strategy ensures that the drive system has high dynamic performance for a wide range of rotor speeds and leads to a significant energy saving under different load operating conditions
A Review on Real-Time Simulation of CNC Machine Tool Dynamics
No full textThis paper is an endeavour to critically appraise the existing methods used for real-time simulation of machine tool dynamics with the emphasis on modelling and simulation of the dynamic behaviour of CNC machine tool feed drives and mechatronic systems for machine tools. The actual approaches for linking the feed drive models with structural models for CNC machine tools are examined. Also the feasibility of using the multidisciplinary approach employing the concepts of virtual machine tools and virtual machining into the design and control processes related to manufacturing process is analysed
Five-Axis Machine Tool Condition Monitoring Using dSPACE Real-Time System
No full textThis paper presents the design, development and SIMULINK implementation of the lumped parameter model of C-axis drive from GEISS five-axis CNC machine tool. The simulated results compare well with the experimental data measured from the actual machine. Also the paper describes the steps for data acquisition using ControlDesk and hardware-in-the-loop implementation of the drive models in dSPACE real-time system. The main components of the HIL system are: the drive model simulation and input – output (I/O) modules for receiving the real controller outputs. The paper explains how the experimental data obtained from the data acquisition process using dSPACE real-time system can be used for the development of machine tool diagnosis and prognosis systems that facilitate the improvement of maintenance activities
Hybrid modelling and simulation of a computer numerical control machine tool feed drive
No full textThe paper presents a new approach to the modelling and simulation of a computer numerical control (CNC) machine tool feed drive. The hybrid model of the drive incorporates a distributed load, explicit damping factors and measured non-linear effects in order to achieve a realistic dynamic performance. In this way, the shortcomings of traditional modelling methods applied to CNC machine tool axis drives are overcome. A MATLAB/SIMULINK package was used to simulate this new model for a CNC machine tool feed drive. A novel hybrid model with a distributed load, explicit damping factors, backlash and friction was developed and shown to have a similar dynamic response to the machine tool feed drive system under the same conditions. The simulated results display resonance frequencies, while the lumped-parameter models generate only the response of a second-order elemen
The New School-Based Learning (SBL) to Work-Based Learning (WBL) Transition Module: A Practical Implementation in the Technical and Vocational Education (TVE) System in Bahrain
No full textThis paper diagnoses the implementation of a new engineering course entitled „school-based learning (SBL) to work-based learning (WBL) transition module‟ in the Bahrain Technical and Vocational Education (TVE) learning environment. The module was designed to incorporate an innovative education and training approach with a variety of learning activities that are included in various learning case studies. Each case study was based on with learning objectives coupled with desired learning outcomes. The TVE students should meet the desired outcomes after the completion of the learning activities and assessments. To help with the implementation phase of the new module, the authors developed guidelines for each case study. The guidelines incorporated learning activities to be delivered in an integrated learning environment. The skills to be transferred were related to cognitive, affective, and technical proficiencies. The guidelines included structured instructions to help students during the learning process. In addition, technology was introduced to improve learning effectiveness and flexibility. The guidelines include learning indicators for each learning activity and were based on their interrelation with competencies to be achieved with respect to modern industrial requirements. Each learning indicator was then correlated against the type of learning environment, teaching and learning styles, examples of mode of delivery, and assessment strategy. Also, the learning activities were supported by technological features such as discussion forums for social perception and engagement and immediate feedback exercises for self-motivation. Through the developed module, TVE teachers can effectively manage the teaching and learning process as well as the assessment strategy to satisfy students‟ individual requirements and enable them to meet workplace requirements
Trends and policy issues for the e-learning implementation in Libyan universities
No full textThis paper provides an overview the current trends and the policy issues for e-learning implementation in Libyan universities LUs.; where is present a sample model to comparative between two questionnaires in 2009& 2013; as a technique to evolution the e-learning policy implementation process in LUs. The paper emphasizes that in spite of the drawbacks faced by most HE institutions, some have managed to successfully introduce e-learning into their strategies.
This paper concludes brief considerations of issues of the implementation policy; difficulties in the process and other challenges.
Finally the paper aims into: Provision of a study on overall difficulties of the followed policy initiatives of e-learning implementation into the decision-makers in LUs; provision of conception to the developers to consider the strength and the weakness points when new strategies mode. And provision a set of suggestions for improving the effectiveness of the e-learning systems usage in Libyan HE based on the results of these SWOT analyses
Improving the Dynamic Performance of Five-Axis CNC Machine Tool by using the Software-in-the-Loop (SIL) Platform
No full textThe paper presents the development and implementation of a Software-in-the-loop (SIL) platform allowing the real-time simulation of the hybrid model of five-axis CNC machine tool which is implemented in SIMULINK. The interfacing between dSPACE software and the feed drives models in SIMULINK is explined. The values for the simulated positioning errors between the position demand and simulated position of orthogonal trimming head for the gantry axis are in the order of microns so proposed SIL model is validated. The accurate SIL platform could be used to build and optimise the machining process models including CNC machine tools under cutting conditions and improve machines’ dynamic performance
An Improved Lab Skills Model and its Application to the Computer Science Course at Omar Al-Mukhtar University, Libya
No full textAbstract
This paper provides an identification of the existing skills gap between school-based learning (SBL) and laboratory-based learning (LBL) in the Computing Department within the Faculty of Science at Omar Al- Mukhtar University in Libya. The authors developed a questionnaire which was completed by lecturers, laboratory demonstrators and stu- dents. The aim was to discover these stakeholders’ perceptions about the gap between the students’ skills during SBL activities and those required by LBL sessions. The questions referred to skills related to three learn- ing domains: cognitive, psychomotor and affective. The findings show there are two most significant IT skills gap and group work skills, and others are lack of materials, lack of understanding of theoretical issues necessary to perform exercises, limited access to IT, a lack of develop- ment processes, poor curriculum review and limited links between prac- tical tasks and theoretical content. The results of quantitative and quali- tative analysis of the responses were used to develop an LBL skills model comprising the hard and soft skills required for lab sessions. This pro- posed model will be used to design and develop supplementary teaching and learning activities and materials which will increase the quality of stu- dent learning and satisfaction
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