The capture of a target spacecraft by a chaser is an on-orbit docking operation that requires an accurate, reliable, and robust object recognition algorithm. Vision-based guided spacecraft relative motion during close-proximity maneuvers has been consecutively applied using dynamic modeling as a spacecraft on-orbit service system. This research constructs a vision-based pose estimation model that performs image processing via a deep convolutional neural network. The pose estimation model was constructed by repurposing a modified pretrained GoogLeNet model with the available Unreal Engine 4 rendered dataset of the Soyuz spacecraft. In the implementation, the convolutional neural network learns from the data samples to create correlations between the images and the spacecraft’s six degrees-of-freedom parameters. The experiment has compared an exponential-based loss function and a weighted Euclidean-based loss function. Using the weighted Euclidean-based loss function, the implemented pose estimation model achieved moderately high performance with a position accuracy of 92.53 percent and an error of 1.2 m. The in-attitude prediction accuracy can reach 87.93 percent, and the errors in the three Euler angles do not exceed 7.6 degrees. This research can contribute to spacecraft detection and tracking problems. Although the finished vision-based model is specific to the environment of synthetic dataset, the model could be trained further to address actual docking operations in the future.
In one, docking is defined as “when one incoming spacecraft rendezvous with another spacecraft and flies a controlled collision trajectory in such a manner to align and mesh the interface mechanisms”, and defined docking as an on-orbital service to connect two free-flying man-made space objects. The service should be supported by an accurate, reliable, and robust positioning and orientation (pose) estimation system. Therefore, pose estimation is an essential process in an on-orbit spacecraft docking operation. The position estimation can be obtained by the most well-known cooperative measurement, a Global Positioning System (GPS), while the spacecraft attitude can be measured by an installed Inertial Measurement Unit (IMU). However, these methods are not applicable to non-cooperative targets. Many studies and missions have been performed by focusing on mutually cooperative satellites. However, the demand for non-cooperative satellites may increase in the future. Therefore, determining the attitude of non-cooperative spacecrafts is a challenging technological research problem that can improve spacecraft docking operations. One traditional method, which is based on spacecraft control principles, is to estimate the position and attitude of a spacecraft using the equations of motion, which are a function of time. However, the prediction using a spacecraft equation of motion needs support from the sensor fusion to achieve the highest accuracy of the state estimation algorithm. For non-cooperative spacecraft, a vision-based pose estimator is currently developing for space application with a faster and more powerful computational resource.
คณะวิทยาศาสตร์
This study aimed to investigate the effectiveness of extracts from moringa seeds, roselle seeds, and tamarind seeds as coagulants to improve water quality in surface water sources. Extracts from these seeds serve as environmentally friendly coagulants and provide alternative options for enhancing surface water quality. The turbidity of surface water sources ranged between 14 and 24 NTU. The coagulation process used the Jar Test method, where the moringa seed, roselle seed, and tamarind seed extracts functioned as both primary coagulants and coagulant aids. In the preparation process, the seeds were finely ground and extracted using a 0.5-M sodium chloride (NaCl) solution. These extracts were then applied as coagulants to reduce turbidity and enhance water quality, with each concentration tested in 300 ml of water. The results indicated that the most effective way to remove turbidity using 2,000 mg/L of moringa seed extract, achieving a turbidity reduction of approximately 73.19% at a cost of 0.0309 baht per 300 ml of water. Followed by Tamarind seed extract, with a concentration of 4,000 mg/L, followed with a turbidity reduction of approximately 56.75% at a cost of 0.0933 baht per 300 ml. Lastly, roselle seed extract at 6,000 mg/L achieved a turbidity reduction of approximately 32.67% at a cost of 0.0567 baht per 300 ml of water.
คณะบริหารธุรกิจ
JALA is a brand that established a business around jasmine rice wax scented candles with the aim of addressing the stress people face in everyday life. The brand utilizes "Aromatherapy" to help relax the mind and alleviate stress. The scented candles made from jasmine rice wax are an innovative product, distinguished by their clean burn, safety for users and the environment, and high vitamin E content that nourishes the skin. They also retain a unique fragrance that provides true relaxation. JALA aims to offer products that blend traditional Thai elements with modern design, making their scented candles not only therapeutic but also a reflection of Thai culture and modern identity. The brand caters to health-conscious and environmentally aware consumers.
คณะวิศวกรรมศาสตร์
A small hydroponic vegetable growing system simulation kit with water flow system that monitors, maintains and controls the amount of fertilizer in the system.