Browsing by Author "Cook, M. V."
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Item Open Access Aerodynamic circulation control for flapless flight control of an unmanned air vehicle(Cranfield University, 2009-01) Buonanno, Annalisa; Cook, M. V.The supporting Flight Dynamics research contribution to the design of Demon, a flapless UAV demonstrator which is the subject of the national research programme FLAVIIR, is described in this thesis. In particular, an integrated flight control and fluidic control system which employs aerodynamic circulation control (CC) to enhance, or replace a conventional aileron is presented. The elimination, or reduction in size, of hinged flight control surfaces on an aircraft offers the possibility of reducing aircraft signature and reducing maintenance requirements; fluidic maneuver effectors provide the opportunity to produce the forces and moments required for flight vehicle maneuvering without using conventional control surfaces. A novel alternative to a conventional single slot trailing edge CC actuator that enables proportional bi-directional control was developed. The CC actuator was manufactured and tested, and experimental evaluation confirmed that bi-directional incremental lift generation comparable to that produced by a mechanical flap of similar trailing edge span is entirely feasible. Wind tunnel tests of a 50% full-span scale Demon model were carried out to establish a representative aerodynamic model of the vehicle. A high fidelity 6DoF simulation of the air vehicle was developed, based on the wind tunnel data and was used to assess vehicle trim, stability and control properties. A mathematical model of the flow control actuator, for interfacing the CC system with the flight control system, was developed and incorporated in the dynamic model of the vehicle. The model determined flapless performance and controllability of the aircraft and, in particular, specific saturation limits and their impact on different phases of flight. Also, the requirements for a secondary air supply system for the CC system and practical values of the volumetric air flow requirement have been assessed. A semi-autonomous primary Flight Control System to enable command and control by a remote pilot throughout the flight was developed. A novel re-configurable control architecture that shares control moment demand between conventional flaps and fluidic motivators was designed and demonstrated to provide a sufficient degree of safety and a flexibility to facilitate future experimental flight research. The results of the research study showed the CC actuator to be a practical solution to the problem of direct flow control at subsonic velocities and, hence, to have significant potential to act as a direct replacement for a flap type control surface. Roll control power equivalent to that of conventional ailerons can be achieved at practical trailing edge slot blowing conditions. Thus, it is concluded that the CC actuator, in combination with conventional elevator and rudder, can effectively control the Demon over its proposed flight envelope.Item Open Access Aircraft parameter estimation by estimation - before - modelling technique(Cranfield University, 1995-11) Hoff, J. C.; Cook, M. V.The use of the estímation-before-modellíng (EBM) two step identification procedure for the determination of aircraft aerodynamic derivatives from flight test data is analysed and illustrated. In the first step of the identification procedure the usual Extended Kalman Filter (EKF) associated with the Modified Bryson-Frazíer (MBF) smoother is compared with a new alterative filtering and smoothing process. The new smoother is simpler and less computationally demanding than the MBF smoother. However, its main advantage is that it enables simultaneous data smoothing with state derivative estimation, thereby avoiding the need for a separate differentiation algorithm. The new smoother differentiator has an important feature that is the determination of the noise characteristics of the measurement signal under analysis prior to the smoothing process. This is done by variance matching between the theoretical and measured autocorrelation of the innovation process generated by a Kalman filter. The new technique is compared with the old one by determining the aerodynamic models for a EMB-312 Tucano dutch roll manoeuvre. It is demonstrated that the new smoother may be used to replace the MBF. Otherwise the new technique is used in the analysis of the Handley Page Jetstream-100 aircraft low speed controls free phugoid trying to identify the contribution of the power Variation observed during the phugoid to the stability of the oscillation. Finally the models obtained from the phugoid analysis are reprocessed using the Total Least Square regression and the results are compared with those from the ordinary Least Square formulation.Item Open Access The application of a modified stepwise regression (MSR) method to the estimation of aircraft stability and control derivatives(Cranfield University, 1996-04) Hinds, H. A.; Cook, M. V.A programme of research has now been completed in the College of Aeronautics (CoA) at Cranfield University to investigate the use of a Modified Stepwise Regression (MSR) procedure. The technique was applied to data obtained from a small BAe Hawk aircraft model flown in a dynamic wind tunnel facility in order to try to estimate the aerodynamic stability and control derivatives of the model. A variety of preliminary experiments were performed to enable the static stability of the Hawk model to be evaluated and estimates for a limited number of aerodynamic derivatives were obtained. The initial experiments also allowed data acquisition and processing systems to be developed. Experience of flying and controlling the model in the wind tunnel was gained. The MSR technique was implemented in the form of a FORTRAN 77 software program. Computer simulations of both the full scale Hawk aircraft and scaled wind tunnel model were written. MSR was found to produce perfect derivative estimates when using noise-free data produced by the aircraft simulations. Various mathematical models were produced to represent the reduced order small perturbation equations of motion for the Hawk in the wind tunnel. Different methods for re-constructing the perturbation variables were implemented. Although the MSR procedure did not perform optimally with experimental data, some insight into both the MSR method and the practical difficulties associated with using a small dynamic rig has been gained.Item Open Access Application of robust control in unmanned vehicle flight control system design(Cranfield University, 2004-03) Al Swailem, Salah I.; Cook, M. V.The robust loop-shaping control methodology is applied in the flight control system design of the Cranfield A3 Observer unmanned, unstable, catapult launched air vehicle. Detailed linear models for the full operational flight envelope of the air vehicle are developed. The nominal and worst-case models are determined using the v-gap metric. The effect of neglecting subsystems such as actuators and/or computation delays on modelling uncertainty is determined using the v-gap metric and shown to be significant. Detailed designs for the longitudinal, lateral, and the combined full dynamics TDF controllers were carried out. The Hanus command signal conditioning technique is also implemented to overcome actuator saturation and windup. The robust control system is then successfully evaluated in the high fidelity 6DOF non-linear simulation to assess its capability of launch stabilization in extreme cross-wind conditions, control effectiveness in climb, and navigation precision through the prescribed 3D flight path in level cruise. Robust performance and stability of the single-point non-scheduled control law is also demonstrated throughout the full operational flight envelope the air vehicle is capable of and for all flight phases and beyond, to severe launch conditions, such as 33knots crosswind and exaggerated CG shifts. The robust TDF control law is finally compared with the classical PMC law where the actual number of variables to be manipulated manually in the design process are shown to be much less, due to the scheduling process elimination, although the size of the final controller was much higher. The robust control law performance superiority is demonstrated in the non-linear simulation for the full flight envelope and in extreme flight conditions.Item Open Access Application of the ecosystem functions framework to community woodlands(Cranfield University, 2007-02) Agbenyega, Olivia; Burgess, Paul J.; Cook, M. V.The UK government provides financial incentives to land owners who promote community use of newly-planted woodlands. De Groot et al. (2002) have developed a framework for classifying ecosystem functions. This research applies this framework to identify and describe perceptions of the function, use and value of community woodlands in order to inform local management and government policy. The research was an exploratory and descriptive case study with an initial flexible and final fixed stage. A poplar wood (Pegnut Wood) and two mixed-broadleaf woodlands(Clapham Park Wood and Reynolds Wood), all planted in Bedfordshire between 1993 and 1998, provided the case studies. Data collection methods included semi-structured interviews, self-administered structured questionnaires, direct observation, modelling of tree data and review of secondary documents. In total 172 out of 400 local residents, 20 on-site visitors, and 8 other stakeholders (owners, government institutions and conservation groups) gave responses. The primary motivations of the owners for establishing the woods were production, information and habitat functions. However financial cost-benefit analyses indicated negative returns to owners without government grants. In the first set of interviews 43- 58% of the local respondents at each site described the selected woods and community woods as “very important”. There was a significant positive association between nearness to the woods and level of importance. Those who visited the woods placed greatest emphasis on the use of the woods for exercise and recreation (48-64%), and as a wildlife habitat (50-52%). Using the ecosystem function framework, local respondents at Pegnut Wood and Clapham Park Wood placed greatest value on habitat (29-39%) and information functions (33-38%) and lowest value on regulation (14-19%), production (5-8%) and negative functions (7-8%). Respondents at Reynolds Wood placed the greatest relative importance on negative functions (36%). Across the three sites, local respondents placed the greatest relative value on the use of the woodlands as a habitat for wild plants and animals (14%) and to provide landscape beauty (12%). A second set of interviews, focussed on the recreational use of the woodlands, showed that the main purpose for visiting the woods was walking (median frequency of once a month and duration of between 31-60 minutes). Fifteen out of 88 respondents indicated that they were willing to contribute to support the woods. Many of those not in favour felt such support was a government responsibility. Overall, owners, local residents, government and local conservation groups showed similar relative valuations of the different functions and uses of community woodlands, indicating that there was substantial scope for working together. The research showed that it was useful to apply the ecosystem functions framework to community woodlands. It provided a structure for analysing planting objectives and it encouraged a focus on indirect uses. Stakeholders recognised potential negative functions of the woodland, and it proved useful to include these in the framework. We note the challenges in recognising and placing a high value on the regulation function amongst the range of stakeholders. The framework also helped to identify synergies and tensions between stakeholders without the need for monetising values.Item Open Access The design and analysis of a reconfigurable flight control system for advanced civil aircraft(1994-04) Oliva, A. P.; Cook, M. V.This work is concerned with the design of a pitch-rate-command-attitude-hold command and stability augmentation system in order that the augmented aircraft meets the Gibson dropback criterion, the Gibson phase-rate criterion and MIL-F-8785C requirements. The work shows two methods of design, pole-placement and optimal control, and discusses the design procedures, the advantages and disadvantages of each method. The work is also concerned with the redundancy aspect of the control law design, and so not only a sensor based design bu also an observer-based design are investigated. In order to design the observer-based control law. a Doyle-Stein observer was implemented. Two methods showing how to design the observer are discussed and presented, and the special characteristics of this kind of observer are also considered. The performance of the observer-based control law was compared with that of the sensor-based control law. The failure transients and characteristics of the control law are also studied and presented. Finally an evaluation of the control law was carried out with a non-linear model of the B-747 aircraft, and a simple altitude-hold autopilot was designed to work together with the stability augmentation control law.Item Open Access The design and analysis of a reconfigurable flight control system for advanced civil aircraft(1994-04) Oliva, A. P.; Cook, M. V.This work is concerned with the design of a pitch-rate-commandattitude-hold Command and Stability Augmentation System in order that the augmented aircraft meets the Gibson dropback criterion, the Gibson phase-rate criterion and MIL-F—8785C requirements. The work shows two methods of design, pole-placement and optimal control, and discusses the design procedures, the advantages and disadvantages of each method. The work is also concerned with the redundancy aspect of the control law design, and so not only a sensor based design but also an observer-based design are investigated. In order to design the observer-based control law, a Doyle-Stein observer was implemented. Two methods showing how to design the observer are discussed and presented, and the special characteristics of this kind of observer are also considered. The performance of the observer-based control law was compared with that of the sensor-based control law. The failure transients and characteristics of the control law are also studied and presented. Finally an evaluation of the control law was carried out with a non-linear model of the B-747 aircraft, and a simple altitude-hold autopilot was designed to work together with the stability augmentation control law.Item Open Access Design and performance analysis of an adaptive anti-skid braking system for large aircraft(Cranfield University, 2007) Shepherd, A. C.; Cook, M. V.; Papadopoulos, C.lt is the author's contention that a brake control system incorporating the following two features is suitable for high-performance, robust and adaptive anti-skid control. 1. Switching on wheel acceleration with hysteresis, 2. Fixed brake pressure rate control. Furthermore, the author contends that such a system can be developed in the context of large commercial aircraft development and with regard to; Minimal a-priori knowledge of system dynamics, I No requirement for on-line system identification. This thesis documents a programme of research conducted to examine this hypothesis in the context of large commercial aircraft, and in conjunction with Airbus UK at Filton in Bristol. The physical basis for this method of control is examined from first principles, explored in detail through a simulation based experimental process and is subsequently confirmed as a viable means of control. This is further developed into a prototype anti-skid braking control algorithm which in turn is incorporated into a nominal brake control system model. A detailed analysis of the systems performance is then conducted and reported upon. Finally, conclusions are drawn with respect to the aims and objectives documented herein and recommendations for further research are made. The novel aspects of this hypothesis and subsequent algorithm development are as follows, and are to be considered with respect to the current state-of-the-art in the field: 1. The use of a fixed brake pressure rate control to isolate the friction dependent aspects of the system dynamics, 2. The use of a simple switching element which incorporates hysteresis such that when combined with l, allows robust -slip gradient control* to be effected, and 3. The use of brake system response characteristics to drive an optimal wheel acceleration demand signal. The author believes that these three aspects of the anti-skid braking algorithm documented within this thesis combine to provide an effective and pragmatic solution to the problem, and represent a step forward in the state of- the-art as is befitting a research programme of EngD character. 'The gradient of the -slip (friction coefficient vs. wheel slip ratio) curve is controlled.Item Open Access The design development and evaluation of an active control aircraft model wind tunnel facility.(1982-09) Malik, I.A.; Cook, M. V.Recent progress in the field of Active Controls Technology(ACT) has resulted in increased interest in dynamic wind tunnel testing for basic research. The present work reports the findings of a three year research and development programme to build a dynamic wind tunnel testing facility. The task included the design and construction of a controllable dynamically scaled aircraft model, a suspension system to give the model four degrees of freedom, and an electronic control unit to interface with the model for operating the primary controls, for stability augmentation and for providing output signals for measurement purposes. The dynamic characteristics of the model have been recorded for some simulated representative flight conditions and are compared with theoretical predictions and the expected characteristics derived from full size aircraft data. The use of various stability augmentation functions has also been investigated to assess the usefulness of the electronic control unit as a means for providing stability augmentation. The results show the system to have considerable potential as an ACT Simulator. Modifications are suggested for further development of the facility to achieve a higher degree of accuracy and versatility.Item Open Access An experimental study of the longitudinal aerodynamic and static stability characteristics of hang gliders(Cranfield University, 1986-09) Kilkenny, E. A.; Cook, M. V.A mobile experimental test facility has been developed to carry out the aerodynamic evaluation of hang glider wings normally performed in a wind tunnel. Longitudinal aerodynamic data obtained using this facility is presented for three modern hang glider wings, a Silhouette, Demon 175 and Magic 166, together with surface flow patterns for the latter two wings. The longitudinal stability criterion are studied and alternatives established, equivalent to the stick fixed and stick free criterion for conventional aircraft, relevant to weight shift controlled wings. These are based on the pilot's position and control force to trim. The aerodynamic data obtained from the mobile facility is used to calculate these parameters and the longitudinal static stability of each wing is examined. The influence of several rigging parameters, variable by the pilot before flight, on the longitudinal static stability and control of the hang glider are also investigated.Item Open Access Flight control for advanced supersonic transport aircraft handling quality design(Cranfield University, 2001-11) Steer, A. J.; Cook, M. V.Concorde's unique low-speed handling qualities are acceptable when flown in a rigidly procedural manner by experienced pilots. However, to be commercially viable and environmentally acceptable more numerous second generation supersonic transport (SST) aircraft would have increased passenger carrying capacity, range and the flexibility to integrate with sub-sonic air traffic. Their much larger size, weight and inertia compared to Concorde's, combined with increasing levels of relaxed longitudinal stability to improve aerodynamic efficiency, results in unstable dynamics and degraded handling qualities on the final approach, where precise manual flightpath control is required. Modern fly-by-wire command and stability augmentation systems can restore stability, provide task tailored command laws and an associated level of handling qualities. Nonlinear Dynamic Inversion (NDI) enables control law prototyping and analysis for the rapid assessment, of conceptual designs to identify control power and command response requirements using both off-line and real-time simulation. This study has developed and applied NDI, and its realisable form (RNDI), in a novel way to design flight control laws specifically addressing handling quality requirements using selected criteria. Piloted validation has demonstrated that NDI pitch rate command will consistently provide Level 1 low-speed handling qualities in both steady and turbulent conditions. However, the best handling qualities can be achieved through a second order pitch rate response, generated by pre-filters, designed to author-suggested constraints on control anticipation parameter (CAP). The SST pitch rate criterion envelope, modified to ensure positive pitch attitude dropback, can then be applied to verify the time response. The resulting pre-filters are easily applied to RNDI inner loop controllers and would be straightforward to implement with simple and proven sensor requirements. Carefully designed NDI normal acceleration command laws are also capable of generating Level 1 low-speed handling qualities in steady conditions. However, their degraded performance in turbulence was exacerbated, relative to the pitch rate command laws, by the use of a fixed base simulator for pilot evaluation. Further motion based simulation studies would provide, in addition to pitching motion, the normal acceleration response cues necessary for a fair command law comparison to be made.Item Open Access Flight control system design for autonomous UAV carrier landing(Cranfield University, 2004-10) Fitzgerald, Pio; Cook, M. V.The challenge of integrating the UAV fleet into the carrier landing operational structure with respect to navigation and control strategies is addressed. A simulation model was developed which includes an aircraft model, an atmosphere model and an aircraft carrier motion model. The six degree of freedom non-linear aircraft model is based on the aerodynamic characteristics of the Mk 4a Jindivik extended to include rudder, spoiler and thrust vectoring controls, and an undercarriage model. The atmosphere model includes a carrier landing atmospheric disturbance model. The six degree of freedom aircraft carrier motion model is based on the ship motion simulation program SEAWAY. A Navigation System was developed which conforms to current operational procedures and future military navigation goals. This Navigation System continuously predicts the position in space where touchdown on the carrier deck will take place, based on aircraft position, the relative velocity between the aircraft and carrier, and the motion time history of the carrier. A reference flight path to the predicted touchdown point is continuously defined. The aircraft deviation from this flight path is determined and input to the autoland control system. For the purposes of this study perfection prediction is assumed. Automatic flight control systems were developed to assess three control strategies for suitability to the carrier landing task. The focus of this assessment was on vertical glide path deviation control. Direct Lift Control was compared to conventional control and was found to have superior performance, especially in turbulence. As UAV planforms tend to be tailless, and therefore lateral and pitch control are generated by a common aerodynamic surface, thrust vectoring was investigated as a means of alleviating aerodynamic pitch control requirements in the carrier landing task. An Adaptive Approach Speed Controller was developed as an extension of the Navigation System. This system synchronises the time that the aircraft passes over the stern, or ramp, of the carrier with the minimum absolute carrier pitch attitude attainable for a given range of approach speeds. This system was shown to be an effective method of minimising the negative effect that carrier motion has on the clearance between the aircraft and the carrier’s ramp.Item Open Access Flying and handling qualities of a fly-by-wire blended-wing-body civil transport aircraft(Cranfield University, 2003-12) de Castro, Helena V.; Cook, M. V.The blended-wing-body (BWB) configuration appears as a promising contender for the next generation of large transport aircraft. The idea of blending the wing with the fuselage and eliminating the tail is not new, it has long been known that tailless aircraft can suffer from stability and control problems that must be addressed early in the design. This thesis is concerned with identifying and then evaluating the flight dynamics, stability, flight controls and handling qualities of a generic BWB large transport aircraft concept. Longitudinal and lateral-directional static and dynamic stability analysis using aerodynamic data representative of different BWB configurations enabled a better understanding of the BWB aircraft characteristics and identification of the mechanisms that influence its behaviour. The static stability studies revealed that there is limited control power both for the longitudinal and lateral-directional motion. The solution for the longitudinal problem is to limit the static margins to small values around the neutral point, and even to use negative static margins. However, for the directional control problem the solution is to investigate alternative ways of generating directional control power. Additional investigation uncovered dynamic instability due to the low and negative longitudinal and directional static stability. Furthermore, adverse roll and yaw responses were found to aileron inputs. The implementation of a pitch rate command/attitude hold flight control system (FCS) improved the longitudinal basic BWB characteristics to satisfactory levels, or Level 1, flying and handling qualities (FHQ). Although the lateral-directional command and stability FCS also improved the BWB flying and handling qualities it was demonstrated that Level 1 was not achieved for all flight conditions due to limited directional control power. The possibility to use the conventional FHQs criteria and requirements for FCS design and FHQs assessment on BWB configurations was also investigated. Hence, a limited set of simulation trials were undertaken using an augmented BWB configuration. The longitudinal Bandwidth/Phase delay/Gibson dropback criteria, as suggested by the military standards, together with the Generic Control Anticipation Parameter (GCAP) proved possible to use to assess flying and handling qualities of BWB aircraft. For the lateral-directional motion the MIL-F-8785C criteria were used. Although it is possible to assess the FHQ of BWB configuartions using these criteria, more research is recommended specifically on the lateral-directional FHQs criteria and requirements of highly augmented large transport aircraft.Item Open Access Flying qualities and flight control system design for a fly-by-wire transport aircraft(Cranfield University, 1998-09) Gautrey, Jim; Cook, M. V.Fly-by-wire flight control systems are becoming more common in both civil and military aircraft. These systems give many benefits, but also present a new set of problems due to their increased complexity compared to conventional systems and the larger choice of options that they provide. The work presented here considers the application of fly-by-wire to a generic regional transport aircraft. The flying qualities criteria used for typical flying qualities evaluations are described briefly followed by analysis of several past transport aircraft flying qualities programmes against these criteria. From these results, some control law independent design requirements are formulated for a civil aircraft for the approach and landing task. These control law independent flying qualities criteria are intended to be used with any generic rate-like control law for a transport aircraft and enabled a number of different control laws to be designed. The results of a number of flying qualities evaluations are presented. Both an ILS approach task and a formation flying task were used. The effects of windshear were also considered. It was found that control laws which maintain flight path are suitable for the ILS approach task, while most rate-like response characteristics give good flying qualities for the formation flying task. Finally, the conclusions drawn from these evaluations are presented, and both the Civil and Military current airworthiness requirements are assessed. In addition to the flying qualities work, a study is made of the management issues associated with fly-by-wire design. A fly-by-wire aircraft design programme was proposed and the project management issues associated with this were considered. A timescale was proposed for the design process for a generic regional aircraft, and the critical path for this process is presented.Item Open Access Flying qualities of transport aircraft : precognitive or compensatory?(Cranfield University, 1995-06) Field, Edmund; Cook, M. V.The introduction of fly-by-wire electronic flight control systems into transport aircraft has given the flying qualities engineer the opportunity to optimise the flying qualities of these aircraft for their specific tasks. With this technology has come the opportunity to introduce new technologies into the cockpit, such as non-linked or backfed sidesticks and non-backfed throttle levers. A comparative survey of airline pilots flying such a very high technology unconventional aircraft and a high technology but conventional aircraft suggests that these technologies may reduce the available channels of communication to the pilot in the very high technology aircraft, resulting in the possibility of reduced situational awareness. A closed loop piloted simulation survey of ten transport aircraft in current operation was undertaken which demonstrated that they all suffered from flying qualities deficiencies, limiting the performance that the pilot could achieve. In particular poor dynamics precluded the pilot adopting tight closed loop, or compensatory, control. Instead it was necessary to adopt a more open loop, precognitive, technique with medium frequency modulation, resulting in a degradation in landing performance. Through appropriate flight control system design it should be possible to produce aircraft that can be flown using the full range of control inputs from open to closed loop. The major study of this thesis assessed, through piloted simulation evaluations, the suitability of a wide range of longitudinal commanded response types for the approach and landing tasks. It was concluded that a response type that closely resembles that of angle of attack is optimum for these tasks due to its conventional characteristics of speed stability on the approach and monotonic stick forces in the flare. Such a system, appropriately implemented, should allow the transport aircraft pilot the full range of piloted control inputs, from open loop, precognitive, to closed loop, compensatory, resulting in improved landing performance.Item Open Access Initial review of research into the application of modified stepwise regression for the estimation of aircraft stability and control parameters(Cranfield Institute of Technology, College of Aeronautics, 1989) Cook, M. V.; Hinds, H. A.Item Open Access An investigation into the flight dynamics of airships with application to the YEZ-2A(Cranfield University, 1990-10) Gomes, S. B. V.; Cook, M. V.In order to construct a flight dynamics computer simulation model of airship flight with a high degree of fidelity in the aerodynamic modelling, extensive wind tunnel testing was carried out. This was aimed at, first developing some specific airship wind tunnel testing techniques and then to obtain aerodynamic data for the YEZ-2A project airship being designed and built by Airship Industries for the US Navy. The wind tunnel testing techniques so developed insured a good matching between wind tunnel results and flight test data from existing airships. The next step consisted in the construction of the flight dynamics computer simulation model. This was a full six-degree-of-freedom (6 DOF) non-linear model written in the simulation language ACSL, and the wind tunnel generated data for the YEZ-2A airship provided the aerodynamic data base. The computer simulation model was then used to study the YEZ-2A aerodynamic stability modes, to obtain a catalogue of vehicle responses to both aerodynamic and power control inputs and finally to predict some of its longitudinal handling qualities characteristics.Item Open Access Investigation into the hovering flight dynamics and control of a flapping wing micro air vehicle(Cranfield University, 2003-02) Loh, K.; Cook, M. V.The hovering flight of a micro air vehicle was investigated. Various flight control concepts, inspired by observation of insect and bird flight, were investigated in some detail. The concepts make use of flap frequency or phase between the flap and pitch attitudes of the wing to control the force magnitude. Tilt of the stroke plane or fuselage was used to vector the force. A flight control system was designed for each concept investigated. The investigation has revealed that the preferred control concept is one in which force vectoring is achieved by the fuselage tilt through a shift in the centre of gravity location while the force magnitude is controlled by the phase between pitch and flap attitudes. This has the advantage of reducing the vehicle weight while at the same time relaxing the demand of extremely high frequency actuators. The equations of motion based on a multi-body representation of a flapping wing micro air vehicle were derived and these form the basis for the SIMULINK flight simulation program used to carry out the above investigation. The aerodynamic model used for the simulation was obtained from force measurements with a flapping mechanism that allows the model wing to oscillate with two degrees of freedom (flap and pitch). During these measurements, the phase angle between the flap and pitch angles of the model wing was varied to determine the effects on the force magnitude and direction.Item Open Access The Linearised small perturbation equations of motion for an airship(1990-01) Cook, M. V.Item Open Access Measurement of the longitudinal static stability and the moments of inertia of a 1/12th scale model of a B.Ae Hawk(Cranfield Institute of Technology; College of Aeronautics, 1990) Hinds, H. A.; Cook, M. V.