Robust multi-H2 output-feedback approach to aerial refuelling automation of large aircraft via linear matrix inequalities

[摘要] ENGLISH ABSTRACT: In recent years the aviation industry has shown an interest in the airborne refuellingof large transport aircraft to enable increased payload mass at take-off andto extend aircraft range. Due to the large volume of fuel to be transferred, a boomand receptacle refuelling system with a larger fuel transfer rate is employed. Therefuelling operation is particularly difficult and strenuous for the pilot of the receiveraircraft, because the position of the receptacle relative to the tanker aircraft mustbe maintained within a narrow window for a relatively long period of time. Theairborne refuelling of a large aircraft is typically much more difficult than that of afighter aircraft, since the large aircraft is more sluggish, takes much longer to refuel,and has a relatively large distance between its refuelling receptacle and its centre ofmass. These difficulties provide the motivation for developing flight control laws forAutonomous In-Flight Refuelling (AIFR) to alleviate the workload on the pilot.The objective of the research is to design a flight control system that can regulatethe receptacle of a receiver aircraft to remain within the boom envelope of a tankeraircraft in light and medium turbulence. The flight control system must be robustto uncertainties in the aircraft dynamic model, and must obey actuator deflectionand slew rate limits.Literature on AIFR shows a wide range of approaches, including Linear QuadraticRegulator (LQR), μ-synthesis and neural-network based adaptive control, none ofwhich explicitly includes constraints on actuator amplitudes, actuator rates andregulation errors in the design/synthesis. A new approach to designing AIFR flightcontrol laws is proposed, based on Linear Matrix Inequality (LMI) optimisation.The relatively new LMI technique enables optimised regulation of stochastic systemssubject to time-varying uncertainties and coloured noise disturbance, while simultaneouslyconstraining transient behaviour and multiple outputs and actuators tooperate within their amplitude, saturation and slew rate limits. These constraintsare achieved by directly formulating them as inequalities.

[发布机构] Stellenbosch University