Lateral/Directional RCS Attitude Control for Lift Reentry Vehicle in Large Dynamic Pressure Regime

For the existence of aerodynamic coupling and big turbulence of reentry vehicle in large aerodynamic flight status, Conventional method for RCS controller designing is difficult to track the bank angle command quickly and accurately. To solve the problem, according to the feature that the lateral/directional coupling is significant and the yaw channel is more effective and stronger to turbulence when tracking the bank angle, a strategy is proposed by using the roll and yaw channel simultaneously to control the bank angle dynamic. Double loop dynamic inversion controller is designed in which the bank angle loop conduct as outer loop and the roll and yaw angle rate loop as inner loop. The convergence of sideslip angle is guaranteed by improving the design of roll angle rate controller and the influence of the controller parameters to converge mode is analyzed. PWPF modulator is applied to convert command moment into pulse signals. Numerical simulation is carried out to verify the benefits of the proposed control method, the results shows that the present method solved the problem that RCS controller designed in conventional manner, and improve control ability of RCS in large aerodynamic condition.

Experimental pressure evaluation near a sail leading edge under real conditions

The aerodynamic condition corresponding to the optimum sail trim has been long debated; in the present note this aerodynamic aspect of the sails is studied by means of pressure measurements near the sail leading-edge. By analysing the pressure acting on the leading edge zone it can be evidenced that, when the sail is “optimally” trimmed, it is actually in the aerodynamic condition corresponding to the ideal angle of attack.