Path following of a stratospheric satellite by the aid of wind currents

Abstract

Path-following controller of a stratospheric satellite is designed under circumstances of wind currents utilization, parameter uncertainty, input value errors, and external disturbances. In order to reduce the energy consumption of the stratospheric satellite, the stratospheric east (west) wind currents are utilized by the stratospheric satellite to track the desired path. To utilize the wind currents, an air balloon as well as altitude control model are designed. Fuzzy disturbances observers are presented to estimate uncertainties and external disturbances. Input values are quantized by logarithmic quantizers. Rigorous stability analysis proves that path-following errors of the stratospheric satellite can be reduced to zero, and all closed-loop signals are uniformly bounded regardless of uncertainties and disturbances. Simulation results show that the stratospheric satellite can track the desired path well and the proposed control strategy can reduce the energy consumption of the stratospheric satellite effectively.

Analysis and Testing of Variable Height Operating Characteristics of Super-Pressure Balloon Airbag Fan

“…In Equation (10), 𝑄𝑃𝑇 and 𝑄𝑃𝑇 represent the unit time air inflation of fan A and fan B, respectively. In Equation ( 5), 𝑄𝑃𝑇 and 𝑄𝑃𝑇 represent the air inflation per unit power of fan A and fan B, respectively.…”

“…By fitting the performance curve data of fan A and fan B at 0 km (Figure 6 measured 9000 RPM data curve and Figure 11 flow-pressure curve) to a multistage function, the relationship between the fan flow and pressure difference can be obtained. On this basis, the fan's TR and WR under different pressure differences can be calculated by Equations ( 9) and (10).…”

“…Based on Equations ( 8) and (10), the fan's WR value was calculated as presented in Table 5. A positive WR indicates that fan A has a distinct power consumption advantage; the WR-average refers to the arithmetic average of all WR values within the common pressure range of 0-400 Pa of a super-pressure balloon at a certain altitude.…”

“…The vertical motion of a super-pressure balloon in the stratosphere is achieved by changing the buoyancy-weight balance of a super-pressure balloon through techniques such as the throwing solid ballast [9], air ballast height-adjustment technology [10], and connecting multiple balloon systems in series [11]. The horizontal motion is determined by the speed and direction of the wind at the balloon location.…”