Publications 2024
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PublicationMicrostructural and corrosion behavior of D3 tools steel and 440C SS for blade application( 2024-01-01)D3 tools steel and 440C stainless steel (SS) are normally being employed for application such as knife blade and cutting tools. These steels are iron alloys which have high carbon and high chromium content. In this study, lab work focused on the microstructural and corrosion behavior of D3 tools steel and 440C SS after went through heat treatment processes. Heat treatments for both steels were started with normalizing at 1020 ℃, continue with hardening at 1000 ℃ followed by oil quenching. Cryogenic treatment was carried out in liquid nitrogen for 24 hours. The addition of cryogenic heat treatment is believed to increase the hardness and corrosion resistance for steels. Both samples were then tempered at two different tempering temperatures, 160 ℃ and 426 ℃. For corrosion test, the samples were immersed in NaCl solution for 30 days to study the corrosion behavior of D3 tool steel and 440C SS after heat treatment. The mechanical properties of these steels have been investigated using Rockwell hardness machine before heat treatment, after heat treatment (before corrosion) and after corrosion test. Microstructure observation of samples was carried out by scanning electron microscopy. The corrosion rate of these steels was calculated after the corrosion test completed. From the results, the highest hardness is observed for D3 tool steel which tempered at 160 ℃ (54.1 HRC). In terms of microstructural analysis, primary carbide and pearlite in the as-received samples transform to tempered martensite and cementite after heat treatment process. From this research, for corrosion test, heat treated 440C SS sample tempered with 426 ℃ possessed the excellent corrosion resistance with corrosion rate 0.2808 mm/year.
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PublicationA Device-to-Device (D2D) Communication between Mobile Robots using Wireless Communication Protocol in Dynamic Environments( 2024-03-11)Mobile robots must have the ability to guarantee safety for operation in a dynamic environment and close to other moving objects. There are many research had been conducted to make the robot safer by utilizing sensors and big data technology to make the mobile robot able to navigate autonomously and intelligently. One of the key elements in autonomous robots is communication between robots. In this paper, device-to-device (D2D) technology has been used to develop communication between robots. To establish the algorithm for D2D communications, radio frequency (RF) used as communication protocols that can perform D2D communication in real-time applications. The performance of D2D communication was then be assessed in terms of distance and latency. RF transceiver module has been mounted on the robot with Arduino to allow communication between mobile robot to other mobile robots in order to transfer data from robot's sensors to the other mobile robots. By utilizing the gathered information and data, the robot can assess its surroundings and predict the movement of other robots to avoid collisions between robots. The results show that the RF transceiver module is capable to send and receive data between two robots with latency up to 4.865s. It is envisaged that the proposed module can be very useful for developing D2D communication between robots to operate in dynamic environments.
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PublicationReconstruction hyperbola signature of underground object using GPR images for mapping applications( 2024-02-08)Ground penetrating radar has been acknowledged as an effective and efficient technique for non-destructive investigation for near-subsurface exploration that is based on the reflection receiver-transmitter of the antenna when hitting buried objects. An accurate interpretation of GPR data is greatly important in locating and mapping underground objects. Although GPR research has achieved remarkable success, the interpretation of GPR raw data highly depends on the reliance of user experts. Further, unexperienced GPR users are subject to error since the hyperbola signatures may resemble each other. Therefore, this work focuses on the development of a 3D reconstruction of the hyperbola signature of underground objects using GPR images for mapping applications. In this study, 3D reconstruction has been developed based on the Synthetic Aperture Focusing Technique, also known as SAFT. At the first stage, the raw input of GPR images was subjected to zero-time correction and background elimination. Next is the projection of each hyperbola signature by means of B-Scan images to create a 3D image. Then, the resultant 3D images were stacked together, and further 3D interpolation techniques were employed on the images. The experimental studies have been done on GPR data using a metal sphere as a sample. The findings of the study highlight that the SAFT method was able to reconstruct the 3D model of the hyperbola signature and exhibit the ability to provide clues about the location of the underground object through the representation of the voxel point of the images. Based on these results, the SAFT technique provides good insight into the 3D reconstruction of hyperbola signatures using GPR images in mapping applications.
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PublicationSmart irrigation system based IoT for indoor housing farming( 2024-02-08)Irrigation system is widely used in agriculture sector and has significant impacts to the growth of the plantation or crops. Traditional method of irrigation system always counter problems such as time consuming, human labour cost, inefficient of water usage and monitoring challenging throughout the process. Thus to address the issues, this paper proposed the development of smart irrigation system that embedded various types of sensor and Internet of Things (IoT) platform used for monitoring plant growth. In this work, there are three module have been developed which are hardware, software and integration module of the proposed system. In hardware module, Raspberry Pi is used to calculate and process the data based on the sensors parameters. Different types of sensors have been employed such as soil moisture, humidity, temperature, ultrasonic and vision sensors. In this framework, the reading of soil moisture sensor was obtained from the base station. The Raspberry Pi will receive the information and starts to pump the water from the tank until the condition of soil moisture content is normal (i.e. reach the threshold value). In addition, the DHT22 sensor will act as the monitoring system in terms of temperature and humidity data. While, the ultrasonic sensor will send the information to the microprocessor and calculate the water level. Furthermore, the webcam vision is used for monitoring the plant growth during the day and night. While, the dripping process runs in real-time application to the plant. The microcontroller ESP8266 used to control the state of ON or OFF light bulb depending on the value of LDR sensor. Based on the results and monitoring process, the proposed smart irrigation system able to works in promising environment with real time data in which it has been monitored through the IoT platform.
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PublicationdSPACE Implementation of Motor Drives using Asymmetric Converter( 2024-02-01)This paper deals with the dSPACE DS1104 based implementation of closed-loop motor drive system using asymmetric converter. The mathematical model of the drive has been simulated in the MATLAB/Simulink environment to analyze the performance of the drive system. The simulated results are then validated with the experimental investigation. For experimental work, the pulse width modulation (PWM) has been implemented in MATLAB environment with Simulink real-time interface. Meanwhile, the hardware implementation consisting of dSPACE digital signal processor, voltage source inverter and generator-coupled motor. Variable speed test was performed on the loaded motor in open loop and closed-loop design to obtain speed tracking response parameter as well as speed ripple. Overall performance of developed system is satisfactory where in low-speed operation, experimental results show good speed tracking performance with ripple within 20%.