As the relevant technologies develop, energy efficient electric power systems are replacing equivalent hydraulic, pneumatic and mechanical systems. This is most apparent in the transportation sector in which energy efficiency is of primary importance, leading to increased range and reduced vehicle emissions and fuel consumption, essential if the UK is to meet EC emissions targets by 2020. Working towards these targets, the current generation of electric technologies are already providing the back-up and auxiliary systems on the newest civil aircraft and motive power on the very latest hybrid and electric vehicles. Looking to the future, the next generation of civil airliners are expected to use electric power as the primary source (except for propulsion) meaning that they will have an on-board electrical generation capacity of around 1MW. Efficient generation, distribution and consumption of this amount of energy in the face of continuously changing power demands of an aircraft during flight requires complex power conversion systems which add mass to the aircraft, reducing the overall system benefits. This has more impact on smaller aircraft such as helicopters as the mass of the extra equipment needed forms a greater proportion of the total vehicle mass. To truly viable in smaller aircraft, the power conversion systems must be lighter, occupy less space and still be capable of delivering the required power safely, operating much closer to the limit of their capabilities.Broadly, this research programme proposes in will investigate two concepts;1. A low mass power conversion system that could be used to drive electric systems in which require a supply frequency that is at a fixed ratio to that of the primary generation system is proposed and analysed in terms of its stability. The resulting converter would be extremely efficient and would increase the likelihood that large electric power technologies (e.g. for propulsion) could be used on helicopters safely.2. A testing method that will allow the critical pieces of equipment (be they software or hardware) to be dynamically loaded and tested in the lab as if they were present in the complete, real system for which they were designed.Specifically the research will take the form of an in-depth analytical study that will determine theoretically and demonstrate experimentally using real-time dynamic substructuring methods, the dynamic stability and control of the proposed power conversion topology. As the topology does not require an intermediate fully rated power electronics stage, it has many benefits including low mass, very high efficiency and little electro-magnetic interference (EMI) which also means heavy EMI filters will not be required.For validation and a reliable assessment of the true stability of the system under loading, a phase of laboratory-based testing will be conducted that will use and assess state-of-the-art control, real-time numerical modelling coupled with load and source emulation techniques (which combine to form a real-time dynamic substructured test) to accurately reproduce the controlled output of a field-wound aircraft generator, and the fan loading of a propeller, with a view to replicating the dynamic conditions observed under true operating conditions.Finally a phase of full laboratory tests will be conduction to demonstrate the accuracy and validity of the implementation of the real-time dynamically substructured test facility.

This project considers active vibration control of parametrically excited systems (PES). The problem is to develop control strategies for the suppression, or enhancement, of parametric resonances in engineering systems. Active control has the potential to control large amplitudes of vibration and modify the dynamics of the system very efficiently. It is particularly suitable for PES since the dynamics of PES are periodic-time dependent. The appearance of the periodic-time-dependent parameter in the dynamic equation results in a complex response including inherent instabilities, or combined resonances of summed or difference type. Understanding the dynamics of PES and its control is thus the main objective of this research. The control strategy that will be used for PES is based on the receptance method developed by the applicant for linear time-invariant systems. The method has significant advantages, since there is no requirement for knowledge of system matrices, no requirement for model reduction techniques and no requirement for observers to estimate the unmeasured states. The method is entirely based on the measured vibration data; therefore the dynamics of the actuators, sensors and filters are all included in the design of the controller. Other control strategies based on the Floquet theory will also be developed. The control techniques will be implemented on a cable-supported structure, representing a cable-stayed bridge, to demonstrate the practical application of the active control on PES. Many engineering structures are subjected to parametric excitation, which is produced by some external loads interacting with the structure. In civil engineering, Aratsu Bridge in Southern Japan is an example where parametric resonance was the origin of the cracks close to the anchorages. Parametric resonance occurs when the structural frequency coincides with a specific ratio of the parametric excitation frequency. For instance in the Skarnsundet Bridge in Norway, a vertical deck frequency was exactly twice the fundamental cable frequency. Vibration control can be achieved by moving the structural frequency away from that specific ratio using pole placement techniques. In aerospace, parametric resonance can cause flutter of airplane wings due to the interaction of the wing with the aerodynamic loads. Recently, a fatal accident occurred involving a prototype of a business jet due to the tail-plane flutter, and the research aims to develop methods by which such instability can be controlled. In marine engineering, parametric resonance can occur in riser systems due to the interaction of the risers with surface waves. The undesirable dynamic behaviour of these risers can be avoided using tension control. If parametric excitation is not included in the design of these risers, the wave induced vibration can result in instability and even catastrophic failure, thereby causing severe environmental and economic damage so that a more flexible method of active control would make the system safer. The research will also be beneficial in the design of the energy converters such as floaters since it can enhance the parametric resonance, which is used to extract significant amount of power from the wave energy.

This is network proposal that gathers all the national expertise in rotary wing systems: The Vertical Lift Network (VLN). The network addresses technical problems for a special class of vehicles powered by direct lift: conventional helicopters, compound helicopters, tilt-rotors, fan-in-wing vehicles, unmanned air vehicles powered by rotors. It is recognised that no single academic institution has expertise and test facilities to take on these new challenges. Several initiatives in Europe (CleanSky, Horizon 2020, national research programmes in Germany, France, Italy, The Netherlands), the USA (NASA, Boeing, Sikorsky), Russia (TSAGI, MAI, KAI) and possibly also China (CARDC) could undermine the competiveness of the UK. Countries such as Japan (JAXA), Korea (KARI) are also gaining momentum. The proposal brings together expertise across the full spectrum of aerospace engineering, including aerodynamics, computational fluid dynamics, wind tunnel testing, aeroelasticity, aeroacoustics, materials, control systems, power systems, flight dynamics, handling qualities, and systems engineering. Due to this multi-disciplinarity, leading-edge research initiatives can only be addressed by pooling resources together to create critical mass. No single organisation has the know-how to address the upcoming technology challenges. The academic network is to work closely with the industry and government stakeholders to identify the strategic directions of research in the next decade. Other key objectives include the promotion of scientific collaboration, the identification of the funding sources, training of students and scientific dissemination via an annual workshop.

Severe weather can cause cereal and oilseed rape crops to become uprooted or their stems to break, a process called lodging. This means that the crops do not grow to their full potential, the quantity of seed they produce (the yield) is substantially reduced and the quality of the grain decreases meaning that it cannot be used for certain purposes such as bread making. Lodging makes crops more susceptible to infection by fungi which can produce toxic chemicals which render the grain unusable. These impacts of lodging can substantially reduce the value of a crop and there can be additional costs of drying the grain harvested from lodged crops. Hence, it is estimated that lodging can cost UK farmers £170M in a severe lodging year. High winds can also cause oilseed rape pods to shatter which releases the seeds and they cannot be harvested. This costs UK farmers in excess of £7M per year. By taking appropriate action (e.g. choice of crop variety and how it is managed) it is possible for farmers to reduce the likelihood of lodging and pod shatter. However, farmers need information to guide their decisions and currently this is largely absent. This project will develop a computerised system for predicting the risks of lodging and pod shatter. It will be based on a model of how crops behave under conditions of high wind speed and soil moisture that will be developed from field experiments. The system will calculate the distribution of lodging and pod shatter across a farm that is likely to occur under severe weather conditions. This information is useful to farmers for developing plans in advance of a growing season. It will show farmers how weather damage can be reduced by selecting particular crop varieties to plant in particular fields and by adjusting the timing and density of seed planting. The system will also support farmers to make decisions within a growing season. To do this it will use satellite images to monitor the growth of crops early in the growing season and use this information together with scenarios of different weather conditions during the season to predict which fields or parts of fields are likely to be damaged by weather. This will allow farmers to take action to avoid weather damage in vulnerable fields or parts of fields by controlling the growth of crops (by altering the timing or amount of fertiliser and chemical growth regulators) and by applying chemical pod sealants. Later in the growing season the computerised system will download short-range weather forecast information and use this to predict the risks of lodging in the forthcoming weather conditions. If certain fields are predicted to be vulnerable to lodging then the farmer can arrange to harvest those fields before lodging occurs. Overall, the decision-support tool produced by this project will enable farmers to reduce the risks of weather damage to crops. This will increase farmer's capacity to produce food and reduce unnecessary use of chemicals and energy on farms which will be beneficial for the environment.

Adaptive Aerostructures for Power and Transportation Sustainability (AdAPTS) is an Early Career Fellowship research project which will advance an ambitious new approach to the design of aerostructures by harnessing the adaptability of compliance-based morphing to continuously optimise aerodynamic performance. This will allow for greener and more sustainable fixed and rotary wing transportation and wind turbine power generation through reduced aerodynamic drag, increased efficiency and improved resilience to changing operating conditions. Compliance-based adaptive aerostructures are designed to exhibit structural and material flexibility that allows them to change their shape in a smooth and continuous manner. These changes in shape are isolated to certain desired motions in specific areas of an aerodynamic surface, for example the amount of curvature at the rear of an aerofoil, to allow for targeted changes in shape while retaining overall strength. These changes in shape improve the ability of the wing or blade to produce lift, minimise the amount of drag generated, and allow for continuous adaptation to changing operating conditions. Initial work has shown that the family of compliance-based morphing devices developed by the PI can provide significant improvements in performance of 5-25%. While the potential benefits are promising, much work remains to make compliance-based morphing a viable solution. These types of structures are poorly understood, and the underlying technologies need significant development. The poor understanding of the performance and behaviour of these structures is due to their compliant nature, which means that the structural, aerodynamic, and actuation characteristics are all highly coupled - with the aerodynamic loading affecting the actuated shape, which in turn affects the aerodynamics. This coupling requires simulation of all of the physics involved in a cohesive, coupled manner. Furthermore, the structural, material, and actuation technologies used to achieve these smooth and continuous deformed shapes are novel, and therefore significant effort is needed to mature them to the point where they can be used in real-world applications. Finally, industry partners in the fixed wing, rotary wing, and wind turbine fields see the potential in these technologies, but because they are so novel and different from current approaches, work needs to be done to show the specific, quantitative improvements in performance that these technologies can achieve for their applications. To address the three sides of this problem, AdAPTS will undertake an ambitious research programme with three parallel streams of work that will: 1.) create a fully comprehensive analysis framework to better understand the hierarchical, coupled performance of compliance-based morphing structures from the bottom up, 2.) rapidly mature the proposed morphing technologies, and 3.) work directly with industry to analyse and design adaptive structures for their products, and to predict the achievable improvements in performance.