Classical and Intelligence Speed Control Techniques for Separately Excited DC Motor (Published)
| Most industrial process that uses DC Motor requires that DC Motor operates at a desired speed depending on the load and this speed should be sustained during the operational process however, a significant deviation from the desired speed trajectory was observed on the speed characteristic of DC Motor when acted upon by a load. This paper is aim at investigating the best controller for controlling the speed of a Separately Excited DC Motor in which four different controllers were deployed; the classical Proportional Integral (PI) Controller, Fuzzy Logic Controller (FLC), Artificial Neural Network (ANN) Based Controller and the Adaptive Neuro Fuzzy Inference System (ANFIS) Based Controller. The PI controller was designed by tuning its parameters in MATLAB Simulink in which the proportional and the integral gains were obtained for the best performance as 100.83 and 1750.45 respectively whereas the ANN and the ANFIS controllers were trained to mimic the desired plant input and output relationship. The FLC was designed to have single input which is the error signal and single output which is the speed using five membership function which give rise to five fuzzy rules based on Mamdani principle. A transient analysis was carried out on individual controllers using a speed reference of 1600 rpm to 2200 rpm in steps size of 200 rpm and it was observed that the ANFIS controller demonstrated a higher level of performance in tracking the input reference with an average percentage overshoot of 18.25%, a settling time of 1.446 seconds and a steady state error of 0.1%. |
Keywords: ANFIS, ANN, DC motor, Fuzzy Logic Controller, NARMAL-L2, PI controller, Speed
Children’s Beliefs About The Concepts Of Distance, Time And Speed (Published)
The present study was designed to further systematic cross-cultural research in the area of children’s beliefs about distance, time and speed by comparing responses of elementary level students in three different countries (Canada: 150, France: 120, Morocco: 130). A pencil and paper questionnaire was used to collect these beliefs. A striking parallel between responses of students in all three countries emerged. These results are discussed in terms of contradictory findings concerning the universality or ethnocentricity of children’s beliefs about scientific phenomena
Keywords: Belief, Distance, Elementary Children, Qualitative Stydy, Speed, Time, Universality
Service Delivery at Fuel Service Stations: An Evaluation of Consumer Satisfaction in Gaborone, Botswana (Published)
The study sought to evaluate consumer satisfaction with regard to fuelling services in Gaborone, Botswana. The importance of four of the five operations performance objectives (Quality, Speed, Dependability and Flexibility) to the motorists was determined. The performance rating of various fuel service stations (FSSs) on the four operations objectives was determined. The aim was to establish if the FSSs were excelling in those operations objectives considered important by the consumer. Results showed that the order of importance of the four operations performance objectives was: Speed (71.9%), Quality (70.2%), Flexibility (59.6%), and Dependability (56.1%). The most important objective for FSSs to excel in is speed. However, FSSs still need to perform reasonably well in the other objectives as their ratings (all over 50%) indicate that they are also important to the customers. The performance ranking for the FSSs was Quality (93.0%), Dependability (91.2%), Speed (87.7%), and Flexibility (57.9%). The FSSs performed better in the Quality and Dependability objectives yet the Speed objective was the most important to the consumers. Significance testing using the Chi Square Test indicate that the strongest relationship between importance and performance exists for the Flexibility objective (Pearsons correlation-Asymp.Sig = .025) and is weakest for the Speed objective (Pearsons correlation-Asymp.Sig = .105). This indicates that FSSs were not excelling in the objective that is most important to the consumer- Speed. FSSs in Gaborone need to improve service delivery by increasing the speed of serving customers.
Keywords: Dependability, Flexibility, Operation, Performance Objective, Product, Quality, Service, Speed
