查看更多>>摘要：CubeSat standards have greatly simplified the process of satellite development. Understanding the potential of these small satellites has led to their usage in numerous space missions by major space agencies like NASA, ESA, JAXA, and ISRO. In addition, private companies and universities are also entering the sector, as small satellite development is a lot cheaper. The rising number of small satellite launches has necessitated the design and development of deployment technologies for small satellites specifically. The deployment subsystem is one of the crucial subsystems that plays a major role in directing and placing these satellites into the right trajectory. This article presents a deployment system, capable of holding small satellites throughout the launch journey and deploying them into the right trajectory. The major advantage of the system is that it is modular, allowing it to deploy satellites of sizes in the range 1U-4U. The article demonstrates the mechanical design of the proposed deployment system, along with the discussion of the results of the rigorous analysis performed using the model to understand its behavioral response to the variable conditions of space. The analysis carried out includes random vibration analysis, static structural load analysis, and thermal analysis. In addition, the circuit design for the control system of the deployment model to achieve the required objectives within the specified time frame is also presented. The article also explains the process of prototype development, the control system circuit integration, and the operation of the prototype to test the functionality of the proposed deployment system.
查看更多>>摘要：Aircraft loss-of-control in the form of unfavorable aircraft–pilot coupling is a key ongoing safety problem for aviation. This study develops a new active inceptor to mitigate the loss-of-control caused by pilot-induced oscillation. The distinction from existing haptic interfaces is that the spring stiffness of this active inceptor changes with the system error between ideal linear system response and actual manual control system response, thus it can guide and inform the human pilot to change the control behavior. Furthermore, a pilot workload evaluation metric is proposed to evaluate the active inceptor from the perspective of pilot's perception. A feedback signal of the rate tracking loop is used to measure the difficulty of the flight task. The spectral peak of the feedback signal versus both frequency and time is introduced to describe the time-varying pilot workload. Combined with the scalogram-based pilot-induced oscillation metric, different configurations and parameters characteristics of the active inceptor are designed. The simulation results show that the single-gradient configuration and the stiffness k = 800 of the active inceptor can mitigate the loss-of-control effectively. The designed active inceptor can be used for improving flying qualities and alleviating the loss-of-control events in the form of adverse aircraft–pilot coupling.
查看更多>>摘要：The model for simulating the dynamic radar echo from wind turbines plays an important role in enhancing the radar antijamming capabilities of radar. However, the extensively used scattering point spacing model can hardly simulate the influence of the wind turbine's irregular blades, which makes it insufficiently accurate to simulate the radar echo from wind turbines. Therefore, the transverse arrangement is introduced to construct the irregular structure of the wind turbine's blades. Based on the waveform matching, the parameters of the transverse offset are determined, with which the improved model of the wind turbine can be constructed. The Monte Carlo algorithm is used to accelerate the process of searching for the best parameters of the transverse offset. Finally, the scaled model experiment with a GW 77/1500 wind turbine was carried out to verify the accuracy of the improved model, and the calculation times for simulating the radar echoes from 1 to 10 wind turbines were compared, which shows that the improved model can increase the accuracy of radar echo by 40% compared to the traditional model without increasing the calculation scale.
NETL
NSTL
IEEE