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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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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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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
No Abstract Available.
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Classification of Contact Forces in Human-Robot Collaborative Manufacturing Environments

SAE International Journal of Materials and Manufacturing

University of Nottingham-Ran Zhao, Svetan Ratchev
Université de Franche-Comté-Adrien Drouot
  • Journal Article
  • 05-11-01-0001
Published 2018-04-02 by SAE International in United States
This paper presents a machine learning application of the force/torque sensor in a human-robot collaborative manufacturing scenario. The purpose is to simplify the programming for physical interactions between the human operators and industrial robots in a hybrid manufacturing cell which combines several robotic applications, such as parts manipulation, assembly, sealing and painting, etc. A multiclass classifier using Light Gradient Boosting Machine (LightGBM) is first introduced in a robotic application for discriminating five different contact states w.r.t. the force/torque data. A systematic approach to train machine-learning based classifiers is presented, thus opens a door for enabling LightGBM with robotic data process. The total task time is reduced largely because force transitions can be detected on-the-fly. Experiments on an ABB force sensor and an industrial robot demonstrate the feasibility of the proposed method.
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Evaluation of Thermal Roll Formed Thick Composite Panels Using Surface NDT Methods

SAE International Journal of Materials and Manufacturing

Airbus UK-Harvey Brookes, Jon Wright
University of Nottingham-Patrick Land, Petros Stavroulakis, Richard Crossley, Patrick Bointon, Svetan Ratchev, David Branson
  • Journal Article
  • 05-11-01-0005
Published 2017-09-19 by SAE International in United States
Inspection of Composite panels is vital to the assessment of their ability to be fit for purpose. Conventional methods such as X-ray CT and Ultrasonic scanning can be used, however, these are often expensive and time consuming processes. In this paper we investigate the use of off-the-shelf Non-Destructive Test, NDT, equipment utilizing Fringe projection hardware and open source software to rapidly evaluate a series of composite panels. These results are then verified using destructive analysis of the panels to prove the reliability of the rapid NDT methods for use with carbon composite panels. This process allows us to quickly identify regions of geometric intolerance or formed defects without the use of expensive sub-surface scanning systems, enabling a fast and cost effective initial part evaluation system. The focus of this testing series is on 6mm thick pre-preg carbon-epoxy composite laminates that have been laid up using AFP and formed using TRF.
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Variation Aware Assembly Systems for Aircraft Wings

University of Nottingham-Dan R.W. Vaughan, Otto J. Bakker, David Branson, Svetan Ratchev
Published 2016-09-27 by SAE International in United States
Aircraft manufacturers desire to increase production to keep up with anticipated demand. To achieve this, the aerospace industry requires a significant increase in the manufacturing and assembly performance to reach required output levels. This work therefore introduces the Variation Aware Assembly (VAA) concept and identifies its suitability for implementation into aircraft wing assembly processes. The VAA system concept focuses on achieving assemblies towards the nominal dimensions, as opposed to traditional tooling methods that aim to achieve assemblies anywhere within the tolerance band. It enables control of the variation found in Key Characteristics (KC) that will allow for an increase in the assembly quality and product performance. The concept consists of utilizing metrology data from sources both before and during the assembly process, to precisely position parts using motion controllers. In this way the assembly fastening operations can be performed optimally and account for manufacturing induced dimensional variations that reduce cycle times in aircraft wing assembly processes. By alleviating the dimensional variation caused by the upstream manufacturing processes and the inaccuracies in the tooling we will…
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Evaluation of Control Methods for Thermal Roll Forming of Aerospace Composite Materials.

SAE International Journal of Aerospace

Airbus UK-Harvey Brookes, Jon Wright
University of Nottingham-Patrick Land, Luis De Sousa, Svetan Ratchev, David Branson
  • Journal Article
  • 2016-01-2118
Published 2016-09-27 by SAE International in United States
With increased demand for composite materials in the aerospace sector there is a requirement for the development of manufacturing processes that enable larger and more complex geometries, whilst ensuring that the functionality and specific properties of the component are maintained. To achieve this, methods such as thermal roll forming are being considered. This method is relatively new to composite forming in the aerospace field, and as such there are currently issues with the formation of part defects during manufacture. Previous work has shown that precise control of the force applied to the composite surface during forming has the potential to prevent the formation of wrinkle defects. In this paper the development of various control strategies that can robustly adapt to different complex geometries are presented and compared within simulated and small scale experimental environments, on varying surface profiles. Results have found that traditional PID control can be utilized, although its robustness under varying conditions reduces performance in situations that are far from the tuned scenario. This causes the PID controller to struggle with geometries containing…
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Design of a Reconfigurable Assembly Cell for Multiple Aerostructures

University of Nottingham-Thomas G. Jefferson, Richard Crossley, Anthony Smith, Svetan Ratchev
Published 2016-09-27 by SAE International in United States
This paper presents novel development of a reconfigurable assembly cell which assembles multiple aerostructure products. Most aerostructure assembly systems are designed to produce one variant only. For multiple variants, each assembly typically has a dedicated assembly cell, despite most assemblies requiring a process of drilling and fastening to similar tolerances. Assembly systems that produce more than one variant do exist but have long changeover or involve extensive retrofitting. Quick assembly of multiple products using one assembly system offers significant cost savings from reductions in capital expenditure and lead time.Recent trends advocate Reconfigurable Assembly Systems (RAS) as a solution; designed to have exactly the functionality necessary to produce a group of similar components. A state-of-the-art review finds significant benefits in deploying RAS for a group of aerostructures variants. What’s more, improvements to robot accuracy and decreasing costs of capital equipment means reconfigurable systems are becoming more economically viable. Designing the part family for commonality and robotic assembly from the outset enables the assembly system to be quickly customised to each variant using modular tooling. A novel…
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Towards Self-Adaptive Fixturing Systems for Aircraft Wing Assembly

University of Nottingham-Dan Vaughan, David Branson, Otto Jan Bakker, Svetan Ratchev
Published 2015-09-15 by SAE International in United States
The aim of this work was to develop a new assembly process in conjunction with an adaptive fixturing system to improve the assembly process capability of specific aircraft wing assembly processes. The inherently complex aerospace industry requires a step change in its capability to achieve the production ramp up required to meet the global demand. This paper evaluates the capability of adaptive fixtures to identify their suitability for implementation into aircraft wing manufacturing and assembly. To understand the potential benefits of these fixtures, an examination of the current academic practices and an evaluation of the existing industrial solutions is highlighted. The proposed adaptive assembly process was developed to account for the manufacturing induced dimensional variation that causes significant issues in aircraft wing assembly. To test the effectiveness of the adaptive assembly process, an aircraft wing assembly operation was replicated on a demonstrator test rig. The experimental case study is described and positive initial test data is presented. The demonstrator achieved assemblies that were 0.129 mm and 0.114 mm from the actual target. These initial tests…
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