Applied Mechanics and Materials Vol. 735

Abstract: Microstrip ring resonator (MRR) sensor was modeled by simple equivalent lumped element circuits in free space based on simulation data obtained from Microwave Office (AWR) simulator and comparison was made with the measurements using the E5071C Network Analyzer. The calculated reflection coefficient, |G| and complex input impedance Z_in using lumped element model were compared with the measurements results. Both results showed well agreement with a little discrepancy, basically due to imperfect soldering. The MRR was designed to have operating frequencies between 0.5 GHz and 4.5 GHz. The maximum surrounding of magnetic field, H_ϕ is within 15 A/m in free space.

Abstract: This paper presents the application of model predictive controller for controlling a nonlinear 2D gantry crane system with a DC motor as an actuator. The gantry crane system (GCS) dynamics is derived using Lagrange equation method. A model predictive controller is designed based on the linearised GCS and prediction cost function to ensure accurate positioning and oscillation reduction. Simulation via MATLAB and Simulink was performed to investigate the performance of the model predictive controller on the GCS. The controller test was done under several elements altering the behaviour of the system. The closed loop system was analysed considering different cable length, payload mass and trolley position. It was found that the closed loop control meets the main goal of this work, trolley positioning as fast as possible with minimum payload swinging all within a robust input voltage.

Abstract: A review on the recent advancements made on filtennas are presented in this paper. RF fronts ends continue to generate a lot of research attention in communication systems due to the effect it has on the overall bit error rate and SNR. Issues such as compactness, interference and noise are addressed by embedding the bandpass filter into the antenna to form a filtenna. Designing a filtering antenna has its own challenges also. Various techniques (synthesis approach, T shaped resonator or slots.) are being used to design filtennas in order to achieve “weak coupling between the feed and the radiating structure” hence yielding better selectivity. The filter-antenna gain results compared to that of the conventional antennas show better rejection of the out of band gain. This helps reduce interference with adjacent frequency band. This paper presents a review of the techniques, challenges faced and potential research trend in filtering antennas.

Abstract: Hydraulic actuators are widely employed for industrial automation for its high power over weight ratio, functionality in tough operating conditions and low cost. However, the dynamics of hydraulic systems are non-linear and the system subjected to non-smooth and discontinuous non-linearities due to directional change of valve opening, friction, valve overlap and changes of hydraulic pressure acted on valve spool. Taking into account the effect of nonlinear parameter variations such as bulk modulus, compressibility of oil or viscosity of oil, fuzzy logic approach is chosen. Fuzzy control can adapt the inconstant working condition and non-linear system alongside of its robustness. For PWM controlled hydraulic component such as solenoid valve, effective approximation of the flow properties in a solenoid valve is essential. In this paper, the effect of fuzzy logic approach incorporated on pulse width modulation (PWM) controlled hydraulic system is to be investigated and experimentally verified.

Abstract: This paper explains about the controllability effect on delta temperature minimum (ΔT_min) in order to get flexible and operable heat exchanger network (HEN). There are many researches based on design and cost effect to ΔT_min contribution. However, there are lacks of study on how the ΔT_min effect to controllability of HENs. Therefore, this paper focuses on controllability analysis of different HENs design based on ΔT_min contribution. There are six HEN designs were obtained from different ΔT_min values such as 20°C, 25°C, 30°C, 35°C, 40°C and 50°C and has been analyzed. The analysis consists of three different controllability tests which are feasibility, flexibility and sensitivity. Feasibility test is used to check either the HEN design is feasible or not. Next, the feasible HEN design is then analyzed in terms of flexibility. The flexibility test is used to calculate the design flexibility in terms of how much the percentage the design can handle under uncertainties. Lastly is to test the process sensitivity with respect to disturbance changes. Throughout the controllability tests, several options for control structure were built and analyzed. A simple HEN case study was used to analyze the controllability.

Abstract: Human Adaptive Mechatronic (HAM) is an enhance system for Human Machine System (HMS). Instead of one-way relationship between human and machine, HAM system provides two-way relationship between human and machine in order to assist human and to improve human skills in operating the machine. Driving a car is an example of applications where HAM system can be applied. One of the problems of HAM is to quantify the human skill for operating the machine. Therefore, this paper proposed a method to quantify human driving skill using Fuzzy Logic System (FLS). In order to get the best design of FLS for quantifying human driving skill, twelve designs of FLS were designed and tested using computer simulation software. The best design from all twelve designs is then been compared with other method of quantifying human skill for verification. Results show that the design of membership functions for input and output have big impact to the accuracy of the output.

Abstract: Spectrum band from 698-960 MHz has been identified for International Mobile Telecommunications (IMT) by International Telecommunication Union (ITU). This paper provides the analysis of potential scenarios on the band plans for mobile broadband using IMT systems in the 698-960 MHz band based on the published recommendations from ITU and from 3rd Generation Partnership Project (3GPP) in order to provide reference to national administrations in performing its spectrum management role. This study focuses from the perspective of maximizing spectrum utilization of this scarce national resource with consideration of the co-existence requirements, current usages and potential interference between different frequency arrangements.

Abstract: In the early design phase of automotive sector, the flow field around the vehicle is important in decision making on design changes. It would consume a lot of money and time for multiple prototypes development if adopt traditional testing method which is wind tunnel test. Thus, numerical method such as Computational Fluid Dynamics (CFD) simulation plays an important role here. It is very often simulation results been compared with wind tunnel data. However, with various mesh types, meshing methodology, discretization methods and different solver control options in CFD simulation, users may feel low confidence level with the generated simulation results. Thus, a robust modeling and simulation guideline which would help in accurate prediction should be developed due to the industry’s demand for accuracy when comparing CFD to wind tunnel results within short turnaround time. In this paper, a CFD modeling and simulation study was conducted on a simplified automotive model to validate with wind tunnel test results. The wind tunnel environment was reproduced in the simulation setup to include same boundary conditions. Meshing guidelines, turbulence model comparisons and also the best practice for solver setup with respect to accuracy will be presented. Overall, CFD modeling and simulation methods applied in this paper are able to validate the results from experiment accurately within small yaw ranges.

Abstract: It is becoming increasingly difficult to ignore that cost reduction in product system are not supporting the development of innovation. This contradiction becomes a great challenge for any type of industry, to improve the competitive level. In this research, the focuses on the mechanism of cost reduction using Design to Cost (DTC) strategy in achieving cost improvement and innovation. The contradiction is solved using Theory of Inventive Problem Solving (TRIZ) that is integrated into Design To Cost Innovation framework. There are two type of cases introduce in this research that highlight the application and the outcome of TRIZ in Design to Cost framework. From the case studies, the results show that the magnitude of cost improvement and innovation achieved is more than the application of conventional tools in Design to Cost strategy. These change the limitation of mindset in cost reduction without compromise or trade-off, and open up new possibility of research for cost reduction in processes and services for various.

Abstract: Environment deterioration, energy shortage and ever rising fuel price makes green transportation a necessity. Being an alternative to fossil fuels vehicles, Electric Vehicles (EVs) exemplify the most popular approach of electrification to a substantial portion of the transportation sector. Recently, usage of renewable energy resources (RERs) is also increased because of its economic and environmental concerns over traditional resources in the new electric power systems. Variable reliability aspects of RERs increase the complexity of safe and stable operation of grid. Therefore, EV will further increase this uncertainty and variability when being connected randomly to the grid in large scale. This paper not only highlights the EV’s related challenges/issues and presents a brief comprehensive review of recent researches. But, also demonstrates a simulation methodology for analyzing the impact of EVs under various charging scenarios on an independent distribution grid in presence of RERs. The results show the creation of new peak loads which in some cases may exceed the grid capacity and threaten the stability and reliability.