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.
วิทยาเขตชุมพรเขตรอุดมศักดิ์
This project aims to design and develop an eye-tracking system to facilitate communication for paralyzed immobile patients. The system is designed to enable patients to convey their needs to caregivers or family members by detecting and tracking eye movements using the Tobii Eye Tracker 5 device. This approach serves as an alternative communication method, replacing the physical movement or speech of paralyzed patients. The system effectively detects and tracks eye movements at a distance of 55 to 85 centimeters and is designed for installation on a computer to ensure ease of use. The program interface consists of three main sections: (1) a set of emotions, (2) a set of needs, and (3) a set of additional needs. It supports input from a virtual keyboard in both Thai and English and allows users to specify additional needs through eye-tracking-enabled typing. Furthermore, the system can generate synthetic speech for text that is difficult to pronounce aloud, send notification messages via the Line application, and store usage data in a database presented in a dashboard format. System testing revealed that the optimal detection distance ranges from 65 to 75 centimeters, as this range yields an error rate of no more than 1 percent. The system accurately responds to eye movements for communication through sound within 3 seconds when interacting with various function buttons. This eye-tracking system effectively enables paralyzed immobile patients to communicate their emotions and needs, facilitating better understanding and interaction between patients and their caregivers or family members.
คณะอุตสาหกรรมอาหาร
Most rice is consumed as cooked, milled rice, but a small portion is also ground into flour or separated into a starch fraction and used by the food industry as a gluten-free ingredient. This study aims to find out if different types of rice flour and starch, such as white and colored rice, could be used in industry. This study employs green modification techniques to slow down the digestion process by combining polyphenols with starch. Our initial study found that the raw colored rice has a lower glycemic index than other types of rice, such as brown or white rice. Another study that looked at how the quality of colored rice flour was changed by different methods also discovered that out of the six green methods (annealing, heat moisture treatment, ultrasound, pregelatinization, wet-microwave, and dry-microwave). It found that ultrasound improved the polyphenol bioaccessibility in the rice flour and reduced the digestion rate. The pregelatinization process led to the flour having high solubility and an estimated glycemic index. Different techniques affected the flour/starch quality in different ways. Therefore, for further industrial application, it could also be easier to select the method for food product based on their required techno-functional quality of flour/starch. In addition to the modification techniques, this study showed that the high bioaccessible polyphenol content and high polyphenol content in rice greatly slowed down the rate of digestion. This study also open for further exploring the possibility of using high polyphenol agricultural waste to modify starch and flour in a sustainable manner.
คณะอุตสาหกรรมอาหาร
Spent hens are laying hens that are over 18 months to 2 years old and no longer productive. The texture of spent hen meat is significantly tougher compared to broiler chickens, capons, and native chickens. Therefore, to increase the value of spent hens, a study was conducted to modify the texture of the meat by restructuring it with carrageenan and tenderizing it by marinating it in bromelain solution at different concentrations. The experiment found that restructuring with carrageenan and using bromelain enzyme resulted in a newly formed product and significantly improved the tenderness of the meat compared to chicken meat that was not treated with carrageenan and bromelain enzyme.