Journal of Applied Science and Technology

COMPARISON OF SLIDING MODE CONTROLLER AND PID CONTROLLER APPLICATION IN CONTROLLING TWO-DEGREE-OF-FREEDOM ROBOT ARM

Dinh-Hanh Tran — 2024-12-23

The aim of this paper is to present a model of a robotic arm with two degrees of freedom and the application of sliding mode and PID controllers to control the robotic arm. The paper presents the modeling and design of a nonlinear controller for the robot arm. To evaluate the quality and accuracy of the system, the authors created a robot arm model and a control algorithm using MATLAB Simulink software. The simulation results show high accuracy, with the control angles retaining the originally set values. A comparison between sliding mode control and PID control in controlling the robot arm with two degrees of freedom is performed for the angular coordinates of each arm link.

RESEARCH AND DESIGN THE CONTROL SYSTEM AND STABILIZE THE TEMPERATURE OF DONG TAO CHICKEN INCUBATOR

Nguyen Viet Ngu — 2024-11-28

The application of solar energy in the models of production of a small capacity in localities is always necessary to reduce the energy costs during operation, save electricity help to minimize environmental pollution in the with the above criteria, it is suitable for poultry farms, and Hung Yen incubators, which are well-evaluated when using solar energy. The main objective of this paper is to study optimal solutions for the technology of temperature control and stabilization of incubators powered by energy with independent solar energy systems. Simulation research shows that the maximum power point system has fast and accurate speed and good thermal stability control results, reducing the transition time and low static deviations.

ERRORS REDUCTINON OF MEASUREMENT DEVICE BY USING AKIMA INTERPOLATION

Bui Thi Kim Thoa — 2024-11-28

Akima interpolation is an effective tool for signal processing in many problems such as data preprocessing for machine learning models, modeling and simulation data generation and post-processing of sensor data for measurement and control problems. In the field of measurement, most sensors are given in the form of value tables, so they have a finite number of known values and often have nonlinear characteristics, causing large measurement errors, especially in rapidly changing environments. The nature of Akima interpolation is a polynomial interpolation method, which estimates the value of a function at points between known data points, thus providing the ability to continuously characterize the measurement characteristics of the measuring device. This paper will apply the Akima interpolation method to correct errors in temperature measurement. The ability to improve measurement accuracy has been verified by Matlab simulation software and surveying the measurement results of a manufactured experimental temperature measuring device. The measurement error correction algorithm proposed in this study can also be effectively applied to other measured quantities, contributing to diversifying solutions to reduce measurement errors.

IDENTIFYING AND MONITORING INTER-AREA LOW FREQUENCY OSCILLATIONS IN POWER SYSTEMS

Doan Van Dien — 2025-04-01

During operation, the power system is subjected to a series of disturbances and excitations. These disturbances and excitations can cause the system to cause inter-area oscillations. This type of oscillation has a relatively low frequency, characterized by a group of generators in the system oscillating in opposition to another group in another area. Low-frequency oscillations limit the transmission capacity and have the potential to destabilize the system. The identification and monitoring of inter-area oscillation modes is of great significance and needs to be given due attention during the operation of the power system. This paper presents the identification and monitoring of inter-area oscillation modes in the power system using the modal analysis method.

APPLICATION OF LQG ALGORITHM IN THE PROBLEM OF PRECISE POSITION CONTROL OF TWO-DEGREE-OF-FREEDOM MANIPULATOR

Le Thi Minh Tam — 2024-12-25

Robot is the subject of extensive research by many scientists due to their significance in various fields of life and industry. Precise control of a robot’s motion and position not only enhances work efficiency but also ensures safety, quality, and broadens the potential applications in different domains. This article discusses the development of a model and simulation of the LQR and LQG control algorithms for a 2-degree-of-freedom manipulator using MATLAB/Simulink software. The primary objectives are high accuracy, simple processing techniques, and reduced manufacturing costs for the robot. The LQR algorithm provides effective control near the equilibrium point, while the LQG algorithm optimizes control and noise handling. Simulation results demonstrate that the system operates stably, accurately, and reliably, even in the presence of noise.

APPLICATION OF SENSORS IN CONTROLLING AND MONITORING THE OPERATION OF AGRICULTURAL PRODUCT DRYING OVENS

Hoang Thi Hang — 2024-12-05

The article presents the application of some sensors used in controlling and monitoring the operation process of agricultural product drying ovens by the heat drying method. Thereby, it can be seen the application of sensor technology in agricultural production activities to improve production efficiency and output quality of agricultural products. Some sensors are analyzed and used in drying ovens such as: temperature sensors, humidity sensors with measurement parameter characteristics are researched and applied to design and manufacture control circuits for small power agricultural product drying ovens according to the thermal drying method.

SB: A NOVEL DATASET FOR IMPROVING INSECT DETECTION PERFORMANCE

Nguyen Duc Tuan Anh — 2024-12-10

Stink bug are one of the major causes of Longan damage - a crop of considerable economic value that is extensively cultivated in Vietnam. Early detection of this insect pest enables growers to implement effective control measures, thereby enhancing fruit quality and yield. In recent years, convolutional neural network- -based object detection models have garnered significant attention and obtained impressive performance. Nevertheless, the accuracy of detecting stink bug has not met expectations due to the scarcity of adequate datasets for training and evaluation purposes. This study aims to address the challenges associated with stink bug detection by introducing a novel dataset named SB. The SB dataset comprises 4,579 real-world stink bug images with bounding box annotations. The SB dataset is employed to train three state-of-the-art object detection models, including SSD512, RetinaNet, and YOLOv7. Experimental findings indicate that the models achieve pothole detection performance of up to 75.62%.

OPTIMAL CLUSTING ALGORITHM FOR VANET NETWORKS

Dao Manh Linh — 2024-12-20

Clustering plays a crucial role in stabilizing the structure of Vehicular Ad Hoc Networks (VANETs) and supporting Intelligent Transportation Systems (ITS). This paper proposes a novel clustering optimization algorithm, referred to as Cluster Harris Hawks Optimization (C-HHO), which incorporates distance, velocity, and cluster density as key criteria. The C-HHO algorithm models the predatory behavior of Harris hawks to optimize clustering in VANETs. Simulation results using OMNET++, SUMO, VEINS, and INET show that C-HHO outperforms CAMONET, RPSO, and HHOCNET in terms of cluster stability.

RESEARCH ON POWDER METAL PRESSING METHOD IN MANUFACTURING TWO-STAGE GEARS

Nguyen Hong Phong — 2024-12-27

This study will present the study of the powder metal pressing process using numerical simulation method for a 2-stage gear model. First, the powder height will be calculated based on the basic theory of powder metal pressing. The mold model will be designed based on the size of the part and the calculated powder height. Comsol Multiphysics software helps to establish a finite element analysis model to analyze the characteristics of the pressing process. The results of stress, plastic deformation and density have been found. This result provides useful information to help design a suitable mold to press out products that meet the requirements.

STUDY ON THE INFLUENCE OF HYDRAULIC PRESSURE AND WALL ANGLE ON THE FORMING HEIGHT OF FRUSTUM-SHAPED PARTS MADE FROM AA1050 SHEET MATERIAL IN SINGLE-POINT INCREMENTAL FORMING

Luyen The Thanh — 2024-12-20

This paper studies the effects of hydraulic pressure and wall tilt angle on the forming height of a quadrilateral pyramid part from AA1050 aluminum alloy plate, using the hydraulic-assisted single-point incremental forming (HS-SPIF) method. First, to evaluate the effects of hydraulic pressure (P) on the forming height, experiments were carried out with three pressure levels: 0 bar, 0.1 bar and 0.2 bar, while keeping other parameters fixed: sheet thickness (t0) = 1 mm, tool diameter (D) = 6 mm, forming depth (t) = 0.5 mm, spindle speed (S) = 2400 rpm, tool feed rate (F) = 1000 mm/min, and wall tilt angle (α) = 80°. The results show that without using hydraulic pressure, the forming height only reaches 15.85 mm. However, with 0.1 bar oil pressure, the forming height increased significantly by 28.20 % compared to the case without pressure. When the oil pressure was increased to 0.2 bar, the increase was only 9.65 % compared to the case without pressure. Next, with a fixed hydraulic pressure of 0.1 bar, the influence of the wall tilt angle on the forming height was evaluated. The experimental results showed that the forming height tended to increase as the wall tilt angle decreased. These findings not only provide insight into the design limits but also provide important recommendations for the machining of AA1050 plate parts in HS-SPIF technology.

DISSIMILAR WELDING BETWEEN 304 STAINLESS STEEL AND 201 STAINLESS STEEL BY GAS TUNGSTEN ARC WELDING

Quoc Manh Nguyen — 2024-12-23

Stainless steel is widely utilized across several sectors due to its mechanical features and advantages. The non-melting electrode welding technique in a safe, inert gas atmosphere is consistently preferred for welding various materials due to its superior weld quality and versatility. This study used Gas Tungsten Arc Welding (GTAW) to make a joint between SUS-304 stainless steel and SUS-201 stainless steel with an ER-308L welding rod. A universal tensile-compression apparatus assesses the tensile strength of the welded connection, while an electronic optical instrument examines the microstructure (OM) of the welded joint. The test results demonstrated the compatibility of the welding technique with the chosen materials and settings; the highest tensile strength of the weld attained was 655 MPa.

MODELING AND ANALYSIS OF ROTOR VIBRATION REDUCTION EFFICIENCY USING A NOVEL DYNAMIC VIBRATION ABSORBER

Do Huy Tung — 2024-12-10

This study proposed a novel dynamic vibration absorber with a passive wheel immersed in the viscous liquid box to reduce the torsional vibration of a damped rotor. It focuses on establishing the dynamic model of the rotor equipped with the novel dynamic vibration absorber (NDVA) and analyzing the torsional vibration reduction effect of the NDVA. Numerical investigations confirm that the NDVA provides superior performance for reducing the rotor torsional vibration compared to the conventional dynamic vibration absorber (CDVA).

EFFECT OF INTAKE TEMPERATURE ON THE COMBUSTION CHARACTERISTICS OF GASOLINE FUEL WITH COMPRESSION COMBUSTION MODE OF GASOLINE FUEL

Le Vinh Son — 2024-12-25

The intake air temperature is an important factor that determines the combustion characteristics of the GPPC combustion model, controls the formation of diffuse combustion, and has a direct consequence on the formation of toxic emissions of HC, CO, NOx and soot in the GPPC type. In this study, the author investigates that the injection time changes with the operating conditions being kept constant: keeping the injection mass ratio fixed at 50-50, the pilot start of injection -35 CAD ATDC and the main start of injection time at the point of injection. top dead, engine rotational speed 1500 rpm, intake air temperature varies from 165 oC to 205 oC, intake pressure 1 bar and injection pressure 400 bar. Through the experimental results, the simultaneous effects of the combustion process with the cold flame and the jet of the penetrating main injection are evaluated to affect the combustion rate of the main combustion process. In addition, the maximum combustion temperature, the rate of increase of pressure in the cylinder and the combustion efficiency and indicator efficiency of the engine are also evaluated to find the impact of intake temperature on operating mode of the engine.