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.
คณะสถาปัตยกรรม ศิลปะและการออกแบบ
The thesis artwork titled “The Red Mist” presents a narrative adapted from a short story of the same name by Assistant Professor Chatnarong Wisutkul in 2003. The story is set in a future world where people's greed and selfishness have led to a war, forcing them to rely on "breathing machines" to survive in the "red toxic mist." Phakin, a 15-year-old boy, embarks on a journey with a group of refugees. As they pass through abandoned cities, they encounter a boy without a breathing machine who has recently lost his father. Phakin decides to help him, despite objections from others. The boy tries to end his life by shutting off his breathing machine, and when Phakin intervenes to save him, he collapses from inhaling the toxic air. Witnessing Phakin's selfless act, the others are moved and join forces to save both of them. Phakin demonstrates that in difficult times, humans must cooperate and help each other rather than being divided and selfish.
คณะเทคโนโลยีการเกษตร
The objective of this experiment was to determine the effect of nitrogen and potassium concentration combination with photoperiod on the growth of Viola in a plant factory to increase the quality of the products, reduce the production time and increase the production cycle throughout the year. The experimental plan was 3x3 Factorial in CRD with nine treatments and three replications (six plants per replication). The factor of this study was two factors; the first factor was three different concentrations of nitrogen and potassium in ratios of 1:1, 1:2 and 2:1. The second factor was the application of different photoperiods. There were 1) 24-hours photoperiod, 2) 8-hours light/16-hours dark photoperiod (Induced flowering state: 13-hours light/11-hours dark photoperiod) and 3) 5-hours light/3-hours dark photoperiod. Controlled temperature at 25 °C, the EC=1.5-2.0 mS/cm and the pH=5.8-6.5 in all treatment. The result showed that the concentration of N: K in the ratio of 1:1 combined with 24-hour photoperiod was the most vegetative growth and also maximizes reproductive growth. The overall great sensory evaluation was an acceptable level and suitable for cooking or decorating dishes. Therefore, the concentration of N: K in the ratio of 1:1 combined with 24-hour photoperiod is the best treatment to increase the quality of the product, reduce the production time of viola flowers in each cycle from 90-100 days down to 43-45 days which is good for farmers.
วิทยาเขตชุมพรเขตรอุดมศักดิ์
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