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Low Cost Reconfigurable Jig Tooling and In-Process Metrology for High Accuracy Prototype Rotorcraft Wing Assembly

University of Nottingham-Richard J. Crossley, Svetan Ratchev
Published 2019-09-16 by SAE International in United States
Reconfigurable tooling frames consisting of steel box sections and bolted friction clamps offer an opportunity to replace traditional expensive welded steel tooling. This well publicized reconfigurable reusable jig tooling has been investigated for use in the assembly of a prototype compound helicopter wing.Due to the aircraft configuration, the wing design is pinned at both ends and therefore requires a higher degree of end to end accuracy, over the 4m length, than conventional wings. During the investigation some fundamental issues are approached, including:Potential cost savings and variables which effect the business case.Achievable Jig accuracy.Potential sources of instability that may affect accuracy over time.Repeatability of measurements with various features and methods.Typical jig stability over 24hrs including effects of small temperature fluctuations.Deflections that occur due to loading.The cost benefit of reusable tooling in a low volume prototype scenario is examined followed by the design of the jig and location features to enable the accurate build and certification documentation to be completed. A prototype 4m test jig comprising of commercially available components and bespoke machined ‘pick-ups’ is presented.Hardware and…
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Advanced Assembly Solutions for the Airbus RACER Joined-Wing Configuration

University of Nottingham-David Bainbridge, Konstantinos Bacharoudis, Andrea Cini, Alison Turner, Atanas Popov, Svetan Ratchev
Published 2019-09-16 by SAE International in United States
The Rapid And Cost Effective Rotorcraft (RACER) is being developed by Airbus Helicopters (AH) to demonstrate a new Vertical Take-Off and Landing configuration to fill the mobility gap between conventional helicopters and aeroplanes. RACER is a compound rotorcraft featuring wings and multiple rotors. The wing arrangement suggested by AH is defined as a staggered bi-plane joined configuration with an upper and a lower straight wing, either side of the fuselage, connected at their outboard extent to form a triangular structure. The ASTRAL consortium, consisting of the University of Nottingham and GE Aviation Systems, are responsible for the design, manufacture, assembly and testing of the wings. Producing an optimised strategy to assemble a joined-wing configuration for a passenger carrying rotorcraft is challenging and novel. The objective of this work concerns all aspects of assembling the joined-wing structure.The joined-wing and fuselage structures will be produced independently and mated together during the final RACER assembly. A multi-stage process will deliver the joined-wing assembly and ensure it will fit to the fuselage. Producing the individual wing structures requires a…
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Morphological Characterization of Gasoline Soot-in-Oil: Development of Semi-Automated 2D-TEM and Comparison with Novel High-Throughput 3D-TEM

University of Nottingham-Ephraim Haffner-Staton, Antonino La Rocca, Alasdair Cairns, Michael Fay
  • Technical Paper
  • 2019-24-0042
Published 2019-09-09 by SAE International in United States
Characterization of soot nanoparticle morphology can be used to develop understanding of nanoparticle interaction with engine lubricant oil and its additives. It can be used to help direct modelling of soot-induced thickening, and in a more general sense for combatting reductions in engine efficiency that occur with soot-laden oils. Traditional 2D transmission electron microscopy (TEM) characterization possesses several important shortcomings related to accuracy that have prompted development of an alternative 3D characterization technique utilizing electron tomography, known as 3D-TEM. This work details progress made towards facilitating semi-automated image acquisition and processing for location of structures of interest on the TEM grid. Samples were taken from a four cylinder 1.4 L gasoline turbocharged direct injection (GTDI) engine operated in typically extra-urban driving conditions for 20,284 km, with automatic cylinder deactivation enabled. Soot nanoparticles were extracted from the used oil drawn from the sump, and prepared on TEM support grids. From a feedstock of chosen grid locations, 30 soot nanoparticles were reconstructed and characterized in 3D and morphological characterization results compared to those derived using 2D-TEM. Results…
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Open Access

Assessing the Accuracy of Soot Nanoparticle Morphology Measurements Using Three-Dimensional Electron Tomography

University of Nottingham-Ephraim Haffner-Staton, Antonino La Rocca, Alasdair Cairns, Michael McGhee, Mike Fay
Published 2019-04-02 by SAE International in United States
Morphology plays an important role in determining behaviour and impact of soot nanoparticles, including effect on human health, atmospheric optical properties, contribution to engine wear, and role in marine ecology. However, its nanoscopic size has limited the ability to directly measure useful morphological parameters such as surface area and effective volume. Recently, 3D morphology characterization of soot nanoparticles via electron tomography has been the subject of several introductory studies. So-called ‘3D-TEM’ has been posited as an improvement over traditional 2D-TEM characterization due to the elimination of the error-inducing information gap that exists between 3-dimensional soot structures and 2-dimensional TEM projections. Little follow-up work has been performed due to difficulties with developing methodologies into robust high-throughput techniques. Recent work by the authors has exhibited significant improvements in efficiency, though as yet due consideration has not been given to assessing fidelity of the technique. This is vital to confirm significant and tangible improvements in soot-characterization accuracy that will establish 3D-TEM as a legitimate tool. Synthetic ground-truth data was developed to closely mimic real soot structures and the…
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Soot in the Lubricating Oil: An Overlooked Concern for the Gasoline Direct Injection Engine?

University of Nottingham-Sebastian A. Pfau, Antonino La Rocca, Ephraim Haffner-Staton, Graham A. Rance, Michael W. Fay, Michael McGhee
Published 2019-04-02 by SAE International in United States
Formation of soot is a known phenomenon for diesel engines, however, only recently emerged for gasoline engines with the introduction of direct injection systems. Soot-in-oil samples from a three-cylinder turbocharged gasoline direct injection (GDI) engine have been analysed. The samples were collected from the oil sump after periods of use in predominantly urban driving conditions with start-stop mode activated. Thermogravimetric analysis (TGA) was performed to measure the soot content in the drained oils. Soot deposition rates were similar to previously reported rates for diesel engines, i.e. 1 wt% per 15,000 km, thus indicating a similar importance. Morphology was assessed by transmission electron microscopy (TEM). Images showed fractal agglomerates comprising multiple primary particles with characteristic core-shell nanostructure. Furthermore, large amorphous structures were observed. Primary particle sizes ranged from 12 to 55 nm, with a mean diameter of 30 nm and mode at 31 nm. Particle agglomerates were measured by nanoparticle tracking analysis (NTA). The agglomerates were found to range between 42 and 475 nm, with a mean size of 132 nm and mode at 100 nm.…
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Demonstration of Transformable Manufacturing Systems through the Evolvable Assembly Systems Project

University of Nottingham-David Sanderson, Alison Turner, Emma Shires, Jack Chaplin, Svetan Ratchev
Published 2019-03-19 by SAE International in United States
Evolvable Assembly Systems is a five year UK research council funded project into flexible and reconfigurable manufacturing systems. The principal goal of the research programme has been to define and validate the vision and support architecture, theoretical models, methods and algorithms for Evolvable Assembly Systems as a new platform for open, adaptable, context-aware and cost effective production. The project is now coming to a close; the concepts developed during the project have been implemented on a variety of demonstrators across a number of manufacturing domains including automotive and aerospace assembly. This paper will show the progression of demonstrators and applications as they increase in complexity, specifically focussing on the Future Automated Aerospace Assembly Phase 1 technology demonstrator (FA3D). The FA3D Phase 1 demonstrated automated assembly of aerospace products using precision robotic processes in conjunction with low-cost reconfigurable fixturing supported by large volume metrology. This was underpinned by novel agent-based control for transformable batch-size-of-one production. The paper will conclude by introducing Phase 2 of the Future Automated Aerospace Assembly Demonstrator - currently in development - that…
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Potential Improvements in Turbofan’s Performance by Electric Power Transfer

Hossein Balaghi Enalou
University of Nottingham-Mohamed Rashed, Serhiy Bozhko
Published 2018-10-30 by SAE International in United States
Bleeding in engines is essential to mitigate the unmatched air massflow between low and High Pressure (HP) compressors at low speed settings, thus avoiding unstable operation due to surge and phenomena. However, by emerging the More Electric Aircraft (MEA) the engine is equipped with electrical machines on both high and Low Pressure (LP) spools which enables transfer of power electrically from one spool to another and hence provides the opportunity to operate engine core components closer to their optimum design point at off-design conditions. At lower power setting of the engine, HPC speed can be increased by taking power from LP shaft and feeding it to HP shaft which can lead to the removal of the bleeding system which in turn reduces weight and fuel consumption and help to overcome engine instability issues. Fuel consumption can be decreased by decreasing inconsistent thrust with the aircraft mission for flight and ground idle settings. This paper investigates the idea of power circulation between shafts using a turbofan model developed using Intermediate Control Volume (ICV) method. Results show…
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Transient Stability Analysis of DC Solid State Power Controller (SSPC) for More Electric Aircraft

JiaWei Zhang
University of Nottingham-Jeevan Adhikari, Tao Yang, Mohamed Rashed, Serhiy Bozhko, Patrick W. Wheeler
Published 2018-10-30 by SAE International in United States
The solid state power controller (SSPC) is one of the most important power electronic components of the aircraft electrical power distribution (EPS) systems. This paper presents an architecture of the DC SSPC and provides the mitigation techniques for transient voltage overshoot during its turn-off. The high source side inductance carries breaking current (9xnominal current) just before turnoff and induces large voltage transient across the semiconductor devices. Therefore, the stored inductive energy needs to be dissipated in order to prevent semiconductor switches from over-voltage/thermal breakdown. Three different transient voltage suppression (TVS) devices to reduce voltage stress across switches are included in the paper for detail study. The comprehensive comparison of the TVS devices is presented. In addition, the thermal impact of the TVS devices on the semiconductor switches is also analyzed. Later, the transient simulation model of the SSPC is built in LT-Spice and the effectiveness of the proposed protection mechanisms is verified.
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Modulation Limit Based Control Strategy for More Electric Aircraft Generator System

University of Nottingham-Seang Shen Yeoh, Mohamed Rashed, Serhiy Bozhko
Published 2018-10-30 by SAE International in United States
Vector based control strategies have been extensively employed for drive systems, and in recent times to the More Electric Aircraft (MEA) generator based systems. The control schemes should maintain the bus voltage and adhere to the generator system voltage and current limits throughout a wide speed range. Typically, the current limit is prioritised first due to ease of implementation and simple control structure. As a result, the voltage limit can be exceeded due to change in operating conditions or disturbance factors. In flux weakening regions, this may affect the controllability of the power converter and lead to generator system instability. In this paper, an alternative control strategy has been investigated to address this drawback. The proposed control scheme refers to the modulation index limit which is the ratio between the power converter input and output voltages as the voltage limit. The control scheme uses a dynamic limit for the generator reference voltages such that the modulation index limit is adhered. Furthermore, a controller is introduced to address the lack of current limit of the proposed…
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ERRATUM: Classification of Contact Forces in Human-Robot Collaborative Manufacturing Environments

SAE International Journal of Materials and Manufacturing

University of Nottingham-Ran Zhao, Adrien Drouot, Svetan Ratchev
  • Journal Article
  • 05-11-01-0001.1
Published 2018-06-07 by SAE International in United States
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