In this paper, an efficient approach to design and optimize a flight controller of a small-scale unmanned helicopter is proposed. Given the identified helicopter model, the Linear Quadratic Gaussian/Loop Transfer Recovery (LQG/LTR) robust control method is applied for trajectory tracking and attitude control of the helicopter with a two-loop hierarchical control architecture. Since the performance of the controller extremely depends on its weighting matrices, the Artificial Bee Colony (ABC) algorithm is introduced to automatically select the parameters of the matrices. Comparative studies between optimal algorithms are also carried out. A series of flight experiments and simulations are conducted to investigate the effectiveness and robustness of the proposed optimised controller.

The pressure oscillation and terminal shock motion in a two dimensional inlet, which was designed for tandem configuration turbine-based combined cycle propulsion systems was investigated experimentally and numerically, respectively. The inlet was characterised by a bleed cavity upstream the inlet throat, an S-shape rectangular-to-circular diffuser and flowpaths for a turbine and a ramjet engine. The terminal shock motion was calculated through a second-order unsteady Reynolds-averaged Navier-Stokes scheme. The pressure and the terminal shock were unsteady when the combined cycle inlet operated at different conditions. With the terminal shock located in the throat and at the shoulder of the third ramp of the TBCC inlet, the pressure oscillation was significant and the shock exhibited unsteady streamwise motion with an oscillatory pattern. The amplitude of shock oscillation at these two conditions was 6mm and 12mm, respectively. When the shock was located downstream of the throat and upstream of the cowl lip, it oscillated in a small range. We defined this motion as the “shake” of the shock. This unsteady behaviour of the shock was caused by flow separation in the combined cycle inlet diffuser.

This paper investigates the effects of the design variables of an aerial deployment mechanism on the robustness of the aerial deployment through a multibody dynamics simulation. The aircraft is modelled as three joined rigid bodies: a right wing, a left wing and a centre body. A spring-loaded hinge is adopted as an actuator for deployment. The design variables are the hinge torque and the deployment timing. The robustness is evaluated using a sigma level method. The margins for the safe deployment conditions are set for the evaluation functions. The dispersive input variables are the initial drop velocity, the surrounding gust velocity, the initial pitch angle and the initial height. The design point with a deployment torque scale value F of 0.7 and a right-wing deployment delay time TSR of 1.0 s can safely deploy in the low-torque deployment condition. This design point is able to accomplish both a safe deployment and a lightweight deployment mechanism.