Open Access Original Research Article

Robust Control for a 3DOF Articulated Robotic Manipulator Joint Torque under Uncertainties

Chukwudi Emmanuel Agbaraji, Uchenna Henrietta Udeani, Hyacinth Chibueze Inyiama, Christiana Chikodi Okezie

Journal of Engineering Research and Reports, Page 1-13
DOI: 10.9734/jerr/2019/v9i417022

This research work emphasizes on design of a robust control for a 3DOF robotic manipulator under uncertainties. The plant model was achieved using the independent joint method and the uncertainty problem was addressed by designing a robust controller using H-Infinity synthesis which was compared with PID. This was achieved with algorithms implemented in MATLAB. The H-Infinity controller recorded 0dB, while PID controller recorded 0.117dB and 0.061dB for joints I and II respectively in Complementary Sensitivity (T) graph at low frequencies. H-Infinity controller achieved better disturbance rejection characteristics with sensitivity (S) graph recording peak sensitivity of 0.817dB and 1.79dB at joints I and II respectively than PID controller which achieved 3dB and 1.86dB at joints I and II respectively. H-Infinity controller achieved better noise rejection characteristics with T graph recording lower gains at joints I and II respectively at high frequencies than PID controller which recorded higher gains at joints I and II respectively. Thus, it was concluded that the H-Infinity controller achieved better performance and stability robustness characteristics for the joint torque control than the PID.

Open Access Original Research Article

Development of a Sawdust Fluidized Bed Gasifier: Design and Fabrication

O. R. Akinyemi, N. G. Olaiya

Journal of Engineering Research and Reports, Page 1-11
DOI: 10.9734/jerr/2019/v9i417023

Aims: This research involves the development of a sawdust fired fluidized bed reactor for the production of synthetic gas for domestic cooking.

Study Design: A sawdust fired fluidized bed reactor using AutoCAD inventor.

Place and Duration of Study: Department of Mechanical Engineering, Federal University of Technology, Akure Ondo state Nigeria.

Methodology: The reactor consists of a hopper, rolled mild steel plate frame lined with clay which forms the frame, air distributor plate and five radially spaced tuyeres. The reactor is fed with pelletized sawdust, retain heat within it and maintain a temperature of 50⁰C at the external surface to minimize burns.

Results: Air was forced into the plenum, after which the air distributor plate evenly distributed jets of air in the bed resulting in complete and incomplete combustion. Combustible gas was produced after 30 minutes and used to boil water.

Conclusion: The sawdust fired fluidized bed reactor is recommended for domestic household use.

Open Access Original Research Article

Application of Cationic Tapioca to Unmodified Pearl Corn Starch – A Papermaking Handsheet Study

Klaus Dölle, Emily Parsons, Jacob Konecny

Journal of Engineering Research and Reports, Page 1-7
DOI: 10.9734/jerr/2019/v9i417024

An handsheet study was performed to compare the application of unmodified pearl corn starch and cationic tapioca starch on 100% recycled paperboard. To analyze the benefits tensile index, Canadian Standard Freeness, and starch retention was measured. The results found that cationic tapioca starch had the highest tensile index at 61.36 N*m/g for a dosage rate of 16 lbs./ton at a comparable dosage for unmodified pearl corn starch at 48 lbs./ton the tensile index was 56.11 N*m/g. Tests of the Canadian Standard Freeness showed that the unmodified pearl corn starch had the lowest freeness at 34.3 ml. The cationic tapioca starch had a freeness of 53.5 ml. For starch retention, more starch was retained in the sheet with cationic tapioca starch, with only 0.0065 grams ending up in the filtrate, compared to 0.015 grams of filtrate for the sheet containing unmodified pearl corn starch.

Open Access Original Research Article

Performance Evaluation of a Refrigeration System for Fresh Maize Storage

O. O. Caleb, N. G. Olaiya, M. A. Akintunde

Journal of Engineering Research and Reports, Page 1-9
DOI: 10.9734/jerr/2019/v9i417025

Aims: In this research project, a refrigeration system that will preserve the quality of fresh maize was developed.

Study Design:  Design of refrigeration system.

Place and Duration of Study: Department of Industrial and Production Engineering, Federal University of Technology, Akure, Ondo State, Nigeria, between August 2017 and February 2018.

Methodology: The designed system consists of a cooling cabinet, compressor, condenser and an evaporator. The cabinet was designed to store up to 15 kg of maize and a compressor of 1/6 hp was used. The equivalent condenser and evaporator were selected with an equivalent expansion valve. R134a was used as the refrigerant. The cabinet walls were fabricated from mild steel (outside wall), stainless steel (inner wall) and glass wool (insulator).

Results: The fabricated system stores fresh maize above its freezing temperature of -1ºC. The system operating temperature ranges from -4 to 2.5ºC with a relative humidity of 90 to 95% for eight hours.

Conclusion: The fresh maize was stored for ten days without noticeable changes in the physical appearance and taste of the maize.

Open Access Original Research Article

Package and Process Design Augmentation of QFN Leadframe Device

Rennier S. Rodriguez, Maiden Grace R. Maming, Frederick Ray I. Gomez

Journal of Engineering Research and Reports, Page 1-6
DOI: 10.9734/jerr/2019/v9i417026

Innovations and breakthroughs either through process, equipment or material is known in semiconductor industries as a positive option in overcoming the existing limitations and assembly handicaps. This presentation discusses the assembly methodology and packaging design of a quad-flat no-leads (QFN) devices using grid design molding tool and leadframe with exposed copper tie bar. Realization of this improved package design proposed the removal of mechanical blade as the primary cutting technique of separating the molded leadframes likewise assembly rejection and defect related to the mechanical blade material together with the processing limitations is mitigated as well. Furthermore, the improved design is realized to be a better alternative for manufacturing tighter clearances and unit-unit pitching requirement thus supports densified and critical package design.