Farkhad Ihsan Hariadi

Development of SBC based machine-vision system for PCB board assembly Automatic Optical Inspection

Visual Inspection is an essential part in the quality control in electronic manufacturing industry, especially in PCB assembly processes. With the advance of surface mount technology as a means to increase automation level in electronic assembly line, with production volume achieving thousands of board per day, manual visual inspection becomes increasingly prohitive. For this purpose, Automatic Optical Inspection (AOI) based on machine vision can be used. This method, however requires considerable amount of investment that is not affordable by small companies. In this research work, a low-cost machine vision based on an SBC (Single Board Computer) is developed. Raspberry-Pi™ as a populer SBC offers capability of being interfaced with camera and of running Linux-based operating system such as Ubuntu™. These capabilities enable this board to be used to run sophisticated image-processing programs for machine vision.

Controls of BLDC motors in electric vehicle Testing Simulator

Brushless direct current (BLDC) motor is one of the popular motors in theindustry and automotive. In automotive, this motor is often used in anelectric vehicle (EV) due to its high efficiency. As part of the EV testing phase, EV Testing Simulator is built here by employing two BLDC motors that are mechanically coupled through their axis. One motor simulates an electric motor that drivesthe EV and the other simulatesthe mechanical loads on the driving motor such as frictional, drag, and gravitational forces in the downhill and uphill conditions. A control module of BLDC motor is devised and consists of two sub-modules, namely test-motor control sub-moduleand load-motor control sub-module. Thefirstsub-modulecontrols the speed of the test-motor (i.e. the driving motor of the EV)to simulate a prescribed EV driving cycle. Meanwhile, the second sub-module controls the torque or current of the load-motorto simulate the loading effects on the test-motor. Both sub-moduleshaveBLDC driverswith fixed Direct Torque Control (DTC) and closed loop schemes are therefore required especially for speed control of test-motor control sub-module. When simulating uphill road in which load-motor acts as a generator,load-motor sub-module performs closed loop torque control with a feedback obtained froma simple steady-state estimation of electric torque of the load-motor. Experiment results show thatthe test-motor sub-moduleproduces relatively small speed oscillation around the reference value with a maximum speed of 1800 RPM.The load-motor sub-modulecan simulate load disturbance which generates10-18 A load current for uphill mode and about 9A for downhill mode.

Development FPGA-based Phasor Measurement Unit (PMU) for smartgrid applications

We develop an Electrical instrument of Phasor Measurement Unit (PMU) based on FPGA. This Instrument will use FPGA as main control of measurement and some addition of devices, they are Global Positioning System (GPS), and external Analog to Digital Converter (ADC). GPS is used as time matching and External ADC used as Converter Analog to Digital to measure the value of current and voltage. Overall system is divided into several parts, they are Voltage - Current measurement and GPS data reader. All data will be distributed and transmitted in parallel mode with UART communication. Parallel measurement is needed in order to get a real-time data of current and voltage. Part of Voltage - Current measurement system will need a buffer which transfer the Data from ADC and register file to store the conversion data. GPS data measurement needs UART data receiver since the GPS module using UART to communicate with another device, a Data Parser and UART Transmitter to transfer the parsed data. All of part will be combined into one group and made an instrument for PMU.

Human-Machine Interface for water quality monitoring system of white-legged shrimp pond

In general, this paper proposes the water quality monitoring system in white-legged shrimp ponds with the aim to improve production and cut the cost of maintenance. In particular, it addresses one of the main parts of the system, the HMI. HMI functions to receive data from the RPM measurement. Then, display the values on LCD and status of values whether normal or not by the color of LED. Also, display the status of value with and minus-sign for abnormal condition and plus-sign for the normal condition on LCD. The component condition of HMI represented by LED color. Besides, HMI also stores the measurement results to SD card, and give feedback an alarm signal and SMS if there is a condition that value passes the normal limit. In this paper, the discussion focus lies in the specification, design, implementation, and testing of HMI system. Based on the results of implementation and testing, obtained throughout the components contained in the HMI worked well. They work based on their specifications and design. At the end of the explanation, there is some suggestion for next developments, namely, add more LED on the LED-sensor-board and LED-component-board, improve the received SMS, and provide keypad. Develop algorithms that can adjust date and time manually, handle storing some phone numbers, and manage the SMS sending to those numbers.

Implementation of hash function on embedded-system platform using chaotic tent map algorithm

Hash function has important usage in the cryptography for information security. In this work, we used a chaotic hash function which is based on chaotic tent map with changeable parameter for bitcoin application. The values of the parameters are determined by the position index of messages block character. The chaotic 128-bit hash value was generated by iterating the one dimensional and piecewise tent map followed by applying XOR operation. The final hash value which was translated into hexadecimal format shows that no information of the original message left after processing. This algorithm has large sensitivity to the message itself and the initial value which was determined by the sender of the messages. The algorithm was first implemented in MATLAB and subsequently on STM32F4, an ARM-based Microcontroller board as the embedded platform being used.

Development of ARM Microcontroller-based Quasi-Resonant inverter Induction Heater

This paper presents the results of developing an ARM Microcontroller-based Quasi-Resonant Induction Heater. The induction heater consists of three modules: power circuit, temperature control, and data acquisition system. Power circuit module is used to generate a high frequency electromagnetic field and current to generate heat at the workpiece. Temperature control module is used to control the temperature of the workpiece. It is done by variating the frequency of the switching signal delivered to MOSFET. Data acquisition system module is used to acquire the actual temperature of the workpiece as feedback for the temperature control module and measure the DC current to calculate the power used by the system. The result of the test is the overall induction heater system works well. It can be used to join metals through brazing method at a controlled temperature. The actual temperature of the workpiece and the system performance can be monitored through the GUI.

Development of interface and coordination for control module CNC PCB milling machine

Control module CNC PCB milling machine consist of three sub-modules, first sub-module interfaces and coordination, second sub-module speed control spindle motor and the last sub module position control stepper motor. This paper focuses on implementation and testing of sub-module interfaces and coordination that receive and process 1 to 4 different PCB design input from user and coordinate others two sub-modules. Gerber file as the input converted into G-code which is translate by interpreter data into signal that ready sent from PC to FPGA via serial communication RS232. Then, data that received by FPGA used to integrate spindle motor and stepper motors in PCB milling process. In addition, this submodule can monitor PCB milling process and also monitor the current of motor spindle. Sub-module interface and coordination is implemented on PC via Visual Studio 2013 using Visual Basic.NET programming language and implemented on FPGA DE2-70 via Quartus II 9.0 using Verilog HDL language. As the result, this sub-module interface and coordination generate command signal which has been interpreted to integrate CNC PCB milling machine.

Development of an FPGA-based sub-module as three-phase spindle motor speed controller for CNC PCB milling machine

Spindle motor (three-phase asynchronous AC motor) is an important part of Computer Numerical Control (CNC) Printed Circuit Board (PCB) milling machine, which plays role to engrave the copper layer based on the PCB pattern design. To perform the engraving processes, it is necessary to adjust the spindle motor speed in accordance with the PCB material used. This paper presents the results of implementing a three-phase spindle-motor speed controller based on Field Programmable Gate Array (FPGA). The control method used is fixed Voltage/Frequency (V/F) with Sinusoidal Pulse Width Modulation (SPWM) technique, so that the maximum torque of the motor can be maintained and the harmonic signals can be minimized. This sub-module consists of two main components, namely FPGA and three-phase inverter, which consists of opto-isolation circuit, logic inverter, MOSFET driver, and three-phase full-bridge inverter circuit. The FPGA unit generates digital SPWM signal as input to the inverter to convert DC voltage into three-phase AC voltage according to the given input frequency. Results show that the sub-module can control the speed in the range of 14000-28000 RPM with the corresponding frequency range of 250-500 Hz. The Sub-module also has constant V/F and Speed/Frequency (ω/F) characteristics. In addition, a ramp speed profile used during acceleration and deceleration has also been successfully implemented to address the problem of low starting torque due to the increase of supply frequency.