The limited battery capacity currently restricts the flight duration of unmanned aerial vehicles (UAVs). Additionally, tethered rotorcraft UAVs suffer from low efficiency, and deploying tethered balloons presents significant challenges. Consequently, tethered fixed-wing UAVs exhibit highly promising development prospects. This study designs and constructs both simulation and physical models of a tethered fixed-wing UAV system. With the utilization of methods such as system identification and trust region algorithms, a comprehensive simulation model was developed, and its accuracy was rigorously validated. Furthermore, the feasibility of the system was confirmed through the integration of UAV hardware with a constructed power supply system, incorporating open source flight control software. The results demonstrate that the tethered fixed-wing UAV system is both feasible and reliable, offering rapid deployment capabilities and commendable flight stability. These findings highlight the potential of tethered fixed-wing UAVs as efficient and stable platforms for various applications, laying the groundwork for future research focused on developing more robust and adaptive control systems tailored to the specific challenges posed by tethered operations.

This paper aims to investigate a new method that uses buoyant gas mixed with air to control the floating height of scientific balloons. Firstly, the static characteristics and thermophysical properties of mixed-gas balloons are analyzed. Subsequently, the inflation model and the thermal-dynamic coupled model are established. Furthermore, based on theoretical research, a GUI program is compiled to simulate the ascent of mixed-gas balloons. Finally, flight tests are conducted. As the balloon volume expands to the maximum, the vertical velocity begins to decay and eventually oscillates around 0 m/s, which is consistent with the simulation. In addition, there is a noticeable shift in which the balloon starts to float after climbing to the target altitude, and the difference values between the test and the simulation are less than 350 m. Moreover, the trajectory results are similar to the prediction, and the errors of the end position are less than 2.5 km in horizontal distance. Consequently, this paper provides guidance for balloon-designated ceiling height technology which can allow a single balloon system to be used for tests at multiple heights.

To address the altitude control requirements of high-altitude latex balloons, this paper proposes a novel lightweight electromagnetically actuated valve design. The valve employs a permanent magnet–electromagnet–spring composite structure to achieve rapid opening/closing motions through electromagnetic force control, enabling precise regulation of balloon gas venting. 3D electromagnetic field simulations were conducted to validate the magnetic flux density distribution, while computational fluid dynamics (CFD) simulations based on the Reynolds-averaged Navier–Stokes equations were employed to evaluate the valve’s aerodynamic characteristics. The CFD results confirmed stable venting performance, with near-linear flow–pressure relationships and localized jet structures that support reliable operation under stratospheric conditions. A multidisciplinary optimization framework was further applied to achieve a lightweight structural design of critical components. Experimental results demonstrate that the optimized valve achieves a total mass of 984.69 g with an actuation force of 15.263 N, maintaining stable performance across a temperature range of −60 °C to 25 °C. This study provides an innovative and systematically validated solution for micro-valve design in lighter-than-air vehicles.

Tethered aerostats serve as critical platforms for aerial observation and communication; however, research on their lateral stability under varying wind conditions remains limited. In this study, a comprehensive approach combining dynamic modeling and computational fluid dynamics (CFD) simulations is employed to systematically analyze the lateral dynamic characteristics of an inverted Y-tail tethered aerostat. A nonlinear lateral dynamic model incorporating aerodynamic effects and added inertial terms is developed, and transient CFD simulations are conducted to examine the system’s dynamic responses under different wind directions and wind speeds. The study particularly evaluates the influence of key parameters such as payload position and the main tether point configuration. The results indicate that optimizing payload distribution can significantly enhance stability, manifested by reductions in yaw peaks and roll oscillation amplitudes. Furthermore, it is found that the yaw motion is more sensitive to wind-direction variations, while the roll motion is influenced by the coupled effects of both wind speed and direction. This research provides a valuable theoretical basis and a validated simulation framework for improving the structural design and operational stability of tethered aerostat systems in realistic wind environments.