As the potential of unmanned aerial vehicles rapidly increases, there is a growing interest in rotary vehicles as well as fixed wing. The quadrotor is small agile rotary vehicle controlled by variable speed prop rotors. With no need for a swash plate the vehicle is low cost as well as dynamically simple. In order to achieve autonomous flight, any potential control algorithm must include trajectory generation and trajectory following. Trajectory generation can be done using direct or indirect methods. Indirect methods provide an optimal solution but are hard to solve for anything other than the simplest of cases. Direct methods in comparison are often sub-optimal but can be applied to a wider range of problems. Trajectory optimization is typically performed within the control space, however, by posing the problem in the output space, the problem can be simplified. Differential flatness is a property of some dynamical systems which allows dynamic inversion and hence, output space optimization. Trajectory following can be achieved through any number of linear control techniques, this is demonstrated whereby a single trajectory is followed using LQR, this scheme is limited however, as the vehicle is unable to adapt to environmental changes. Model based predictive control guarantees constraint satisfaction at every time step, this however is time consuming and therefore, a combined controller is proposed benefiting from the adaptable nature of MBPC and the robustness and simplicity of LQR control. There are numerous direct methods for trajectory optimization both in the output and control space. Taranenko’s direct method has a number of benefits over other techniques, including the use of a virtual argument, which separates the optimal path and the speed problem. This enables the algorithm to solve the optimal time problem, the optimal fuel problem or a combination of the two, without a deviation from the optimal path. In order to implement such a control scheme, the issues of feedback, communication and control action computation, require consideration. This work discusses the issues with instrumentation and communication encountered when developing the control system and provides open loop test results. This work also extends the proposed control schemes to consider the problem of multiple vehicle flight rendezvous. Specifically the problem of rendezvous when there is no communication link, limited visibility and no agreed rendezvous point. Using Taranenko’s direct method multiple vehicle rendezvous is simulated.

Personal Air Vehicles (PAVs) are envisaged to be the next logical step in mobility to alleviate modern transport problems. PAVs could combine the freedom of point-to-point personal mobility with the higher speeds of air travel. Hence the principal aim of this research programme was to develop a preliminary design and optimisation methodology for an innovative vertical take-off and landing (VTOL) PAV with a ducted fan propulsion system driven by a single turboshaft engine. A feasibility study conducted at the start of the programme concluded that a ducted fan powered VTOL PAV provides a flexible, quiet and safe point-to-point mobility platform free from runway constraints and any problems associated with jet efflux or exposed rotating components. To satisfy VTOL and forward flight requirements a design and optimisation methodology for ducted fans and contra-rotating lift fans was developed from a series CFD tests. With a single engine driving all the fans, a methodology was developed for the design of a system of interconnecting gears, gearboxes and shafts. To accommodate the propulsion system and all the other internal components of the aircraft, an innovative tri-surface configuration was generated by adopting a systems packaging approach. Weight minimisation through the use of composites and appropriate prediction methods was crucial to reducing the power requirements and fuel consumption. The aerodynamic surface interaction was explored and optimised using a vortex-lattice method. The same approach was also used to estimate the stability derivatives of the aircraft. The overall performance was analysed utilising the data produced from the above methodologies and that also included an analysis of the transition from hover to forward flight. All the above methodologies were integrated to form an automated PAV design synthesis which in combination with a MATLAB global optimiser is capable of producing variants of the baseline aircraft that are capable of meeting different mission and passenger capacity requirements while maximising a specified merit function.

Handling qualities are without doubt one of the primary objectives of the design of modem rotary-wing aircraft, where improved handling qualities increase mission effectiveness and flight safety, and reduce pilot workload. This dissertation provides results of an assessment of gyroplane handling qualities using flight testing and simulation techniques. Since at the time of writing, there are no direct handling qualities requirements and criteria developed for light gyroplanes anywhere in the world, objective handling qualities of the G-UNIV research gyroplane are estimated using criteria from numerous fixed and rotary wing aircraft specifications. To obtain subjective handling qualities gyroplane test manoeuvres must be designed. In this thesis inverse simulation is proposed as a preliminary tool in designing gyroplane manoeuvres. A high fidelity, individual blade/blade element coupled rotor-fuselage mathematical model of a gyroplane, GSIM is developed and successfully coupled with a generic inverse simulation algorithm GENISA to form an inverse simulation package GENISA/GSIM. Two gyroplane manoeuvres, slalom and acceleration-deceleration, are designed based on those from the Aeronautical Design Standard ADS-33E-PRF. A flight test programme for the G-UNIV research gyroplane is conducted to demonstrate the use of the designed gyroplane manoeuvres and obtain subjective handling qualities. Preliminary recommendations are proposed regarding suitability of handling qualities criteria of fixed and rotary wing aircraft. In addition, this dissertation proposes two handling qualities criteria for a light gyroplane, roll quickness and pilot attack criteria for the slalom manoeuvre.