Thanate Khaorapapong

Effect of substrate temperature dependence on six-port reflectometer performance

This paper first investigates the effect of substrate temperature dependence on performances of six-port reflectometer (SPR) designed for measuring complexity permittivity. The temperature-dependent effect on the substrate is described by the variation of dielectric constant (έr) and dissipation factor (tanδ). Here, two printed circuit boards (RO3003® and RO3010®) with two different substrate materials are used for designing the SPRs operating at 4 GHz. The accuracy of these SPRs to predict moisture content in rubber latex over a certain temperature range will be studied. The obtained results indicate that the temperature dependent of the substrate has an impact on the SPR performances.

Classification of Fresh Aromatic Coconuts by Using Polynomial Regression

This paper present the classification of fresh aromatic coconuts into 3 types: single layer, double layer and one and a half layer by inspecting colors at the bottom of coconuts. We take the photos the bottom of coconuts in RGB mode, change the colors into the HSV mode, and then place 4 circles into the image. The 20 photos of each type are used to generate the relation of the rings for each type by using polynomial regression. Finally, we use the polynomial equations to test new 100 fresh aromatic coconuts, the result is 11.76% errors for single layer, 18.6% for one and a half layer and 18.18% error for double layers.

An automatic and rapid system for grading palm bunch using a Kinect camera

Abstract In a trading market, price of oil palm ( Elaeis guineensis ) is negotiated depending some key parameters of the fresh fruit bunch (FFB). Inspectors have been hired by a buyer to grade FFB to accept or reject. The classification results made by human inspection are skeptical and not very reliable if workload is high. We have developed a system to grade FFB depending on its quality. Several palm features are extracted from RGB, near infrared, and depth images, captured with a Microsoft Kinect camera version 2.0 installed in a light-controlled environment on the conveyor line. Two main algorithms for classification have been developed. The first algorithm is called a volume integration scheme (SVIS), which measures the relative volume of palm bunch. The second developed algorithm classifies palm bunch into three grades (L-Grade, M-Grade and H-Grade) based on oil content from Soxhlet extraction. The system achieves 83% accuracy for grading palm bunch within 6 s per one sample, which shows the possibility of using the system in a trading market.

The modeling of screw pump dispenser using DC motor

Recently, the dispenser system has been widely used for holding the electronic manufacture of many devices. It also need an accurate control of the amount of fluid and volume from the semi-conductor. This paper represents the modeling of screw pump dispenser using dc motor used Simulink™ from MATLAB. In the screw pump dispenser there is a very important motor which depends upon the volume, is used in industry liquid droplets. The purpose of this paper is to make model from screw pump dispenser which used as a simulation volume of screw pump dispenser. This paper also includes the description and estimation parameters from dc motor, parameter from motor plug-in modeling of screw pump dispenser, various testing of speed, number of rotation, environment factors, depend volume of screw pump dispenser. Finally this paper compares the results, the different volume between modeling and experiment.

Time-independent human gait modeling using accelerometry data

Human gait analysis has been widely used in many fields of work. Numerous sensor types are applied in gait analysis. Accelerometer is a sensor that is famous to use. Gait was previously analyzed based on time-dependent data from an accelerometer. This will face some problems when a test subject is walking at different speeds. To correct such problem, a time-independent mathematical model for human gait is proposed. A three-axis accelerometer is installed at each foot to collect all three-axis data in Cartesian coordinate. These data are subsequently transformed to spherical coordinate to form a 3-D gait trajectory. Polynomial surface fitting technique is applied to the measured trajectory. In the experimental, about 194 gait cycles are tested and compare with simulation data. From the experimental results, accuracy of the proposed gait model is more than 85%.

A low-cost solution of motor control system for Robocup robots

This paper describes a motor control system for Robocup (small-size league) robot. Our aim was to build high performance robots at a minimal cost. We achieved a low-cost design with the use of cheap motors and use of small DC motors for speed feedback. All controls were completed by a single microcontroller. We also established predictive controllers in software to improve the systempsilas performance.