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The field of parallel kinematics was viewed as being potentially transformational in manufacturing, having multiple potential advantages over conventional serial machine tools and robots. However, the technology never quite achieved market penetration or broad success envisaged. Yet, many of the inherent advantages still exist in terms of stiffness, force capability, and flexibility when compared to more conventional machine structures. Deployment of Parallel Kinematic Machines in Manufacturing examines why parallel kinematic machines have not lived up to original excitement and market interest and what needs to be done to rekindle that interest. A number of key questions and issues need to be explored to advance the technology further. Click here to access the full SAE EDGETM Research Report portfolio.

The aerospace manufacturing industry is, in many ways, one of the most sophisticated commercial manufacturing systems in existence. It uses cutting-edge materials to build highly complex, safety-critical structures and parts. However, it still relies largely upon human skill and dexterity during assembly. There are increasing efforts to introduce automation, but uptake is still relatively low. Why is this and what needs to be done? Some may point to part size or the need for accuracy. However, as with any complex issue, the problems are multifactorial. There are no right or wrong answers to the automation conundrum and indeed there are many contradictions and unsettled aspects still to be resolved. Unsettled Issues on the Viability and Cost-Effectiveness of Automation in Aerospace Manufacturing builds a comprehensive picture of industry views and attitudes backed by technical analysis to answer some of the most pressing questions facing robotic aerospace manufacturing.

This SAE EDGE™ Research Report builds a comprehensive picture of the current state-of-the-art of human-robot applications, identifying key issues to unlock the technology’s potential. It brings together views of recognized thought leaders to understand and deconstruct the myths and realities of human- robot collaboration, and how it could eventually have the impact envisaged by many. Current thinking suggests that the emerging technology of human-robot collaboration provides an ideal solution, combining the flexibility and skill of human operators with the precision, repeatability, and reliability of robots. Yet, the topic tends to generate intense reactions ranging from a “brave new future” for aircraft manufacturing and assembly, to workers living in fear of a robot invasion and lost jobs. It is widely acknowledged that the application of robotics and automation in aerospace manufacturing is significantly lower than might be expected.

In the civil aircraft industry there is a continuous drive to increase the aircraft production rate, particularly for single aisle aircraft where there is a large backlog of orders. One of the bottlenecks is the wing assembly process which is largely manual due to the complexity of the task and the limited accessibility. The presented work describes a general wing build approach for both structure and systems equipping operations. A modified build philosophy is then proposed, concerned with large component pre-equipping, such as skins, spars or ribs. The approach benefits from an offloading of the systems equipping phase and allowing for higher flexibility to organize the pre-equipping stations as separate entities from the overall production line. Its application is presented in the context of an industrial project focused on selecting feasible system candidates for a fixed wing design, based on assembly consideration risks for tooling, interference and access.

Significant effort has been applied to the introduction of automation for the structural assembly of aircraft. However, the equipping of the aircraft with internal services such as hydraulics, fuel, bleed-air and electrics and the attachment of movables such as ailerons and flaps remains almost exclusively manual and little research has been directed towards it. The problem is that the process requires lengthy assembly methods and there are many complex tasks which require high levels of dexterity and judgement from human operators. The parts used are prone to tolerance stack-ups, the tolerance for mating parts is extremely tight (sub-millimetre) and access is very poor. All of these make the application of conventional automation almost impossible. A possible solution is flexible metrology assisted collaborative assembly. This aims to optimise the assembly processes by using a robot to position the parts whilst an operator performs the fixing process.

A modern aircraft wing contains many complex pipes and ducts which, amongst other functions, form the fuel management and bleed air systems. These parts are often fabricated from thin sheet material using a combination of forming and welding and the manufacturing process is predominantly manual requiring highly skilled labor. Since each wing may only contain one or two of each part type the product volumes are very low, typically a few hundred per year. This means that conventional mass production approaches used in, for example the automotive industry, are not economically viable and the parts are thus disproportionately expensive. The current fabrication process involves splitting the component into parts that can be press formed from sheet, laser trimmed and then manually welded together in a fixture. This process requires a perfect fit between the parts whose quality is reliant on the initial forming process.

Measurement assisted assembly is one of the key emerging technologies in airframe manufacture. The use of metrology to assist with the assembly process can significantly reduce the cost and complexity of the required fixtures as well as reducing manual labor input and assembly time. Most of the existing systems use a single metrology system but this paper describes the development and deployment of a network based system that allows the deployment of multiple metrology systems to support either a single task or multiple tasks simultaneously.

Transport is a significant contributor to global Carbon Dioxide and Nitrogen Oxide emissions. The VITAL (Environmentally Friendly Aero Engine) project is an integrated project funded under the European Union Sixth Framework programme that aims to design, manufacture and test the critical technologies required to produce cleaner low noise aero-engines. In particular, it should develop innovative technical solutions to reduce the engine's weight, thereby reducing fuel consumption and hence Carbon Dioxide emission. Prime candidates for weight reduction are the engine casings and structures. One way of achieving this is to move from a casting based manufacturing method to a fabrication method. The use of fabrications for these types of structures is not new and was indeed the standard methodology for older engine types. It was however abandoned in favour of castings due to the high costs associated with the complex fixtures required and the significant manual labour input needed.

The traditional use of simulation software in aerospace manufacturing applications has been as a pre-production tool for the validation of tool paths and the generation of robot programs. Once the process has been proven via simulation, the data is then transferred to the machine or robot and the production process executed. This is a linear approach in which the virtual and real systems are operated independently and in a serial manner. The current capabilities of offline programming (OLP) and simulation systems when combined with appropriate hardware in a flexible manufacturing environment now allow them to be used right at the heart of a manufacturing process, as an integral part of the manufacturing route. In a flexible manufacturing cell such as that developed at the University of Nottingham for the automated assembly and riveting of large aerostructures, a key driver is the need to reduce or eliminate complex and costly jigs and fixtures for part positioning.

This paper describes the final development and testing of a combined riveting and assembly cell for the manufacture of Regional Jet Fuselage panels. The cell consists of three industrial robots, two are used for riveting whilst the third is used for stringer placement. The cell has been tested using both simplified test parts and real airframe components. The paper describes the development and testing of the cell along with the enabling technologies that have been implemented to realise the cell.

As part of an ongoing collaborative research project between The University of Nottingham and Bombardier Aerospace a pair of end-effectors have been developed that allow solid riveting of aircraft fuselage panels to be performed using conventional robots. This paper describes the development and performance testing of a compact process monitoring system and its integration into the riveting end-effector and testing. The developed process monitoring system is based around a miniature CCD camera combined with a novel structured lighting system. The combination of the structured lighting system with image processing techniques means that good quality images of the drilled and countersunk holes and rivets can be obtained despite the confined environment and highly reflective materials involved. The impact of the system on the overall cycle time is also minimised.

This paper describes the current state of development of a highly flexible assembly and auto-riveting system based around multiple robots and compact and innovative riveting and assembly end-effectors. The riveting end-effectors are capable of drilling, countersinking, sealing and upsetting operations. The assembly end-effectors are re-configurable and can handle ant stringer or frame on a Bombardier Aerospace CRJ700 fuselage panel. The cell is also equipped with non-contact metrology systems that are used to compensate for compliance and remove the requirement for large and complex fixtures. The riveting system has been fully evaluated and a number of test coupons submitted for testing. Detailed analysis of these has proved that the resulting riveted joints are of production quality. The final system will be non-product specific allowing a single cell to produce a number of different aircraft components.

The use of simulation is a recognised part of the design process for automated systems and this has been particularly so in the development of the very large machines used in aero-structure manufacture. As part of an ongoing research project at the University of Nottingham a flexible rapid assembly cell is currently being developed that will be capable of manufacturing a number of different aero-structure sub-assemblies. The individual technologies required such as riveting, drilling and assembly have been developed and the complete cell is now being realised. A key enabler for the realisation of the cell has been the use of simulation, both in the development stage and as a central component of the operating and programming systems. This paper will describe the application of simulation techniques within the cell and during its design.

This paper describes the development of highly flexible auto-riveting system based around multiple Tricept robots and compact and innovative end-effectors. The end-effectors are capable of performing drilling, countersinking, sealing and riveting operations. The key to the success of the system is the high repeatability and stiffness of the Tricept robot allied with a very compact end-effector. The compact end-effector allows riveting to be performed in confined areas thus increasing the number of rivets that can be inserted automatically. The end-effectors also contain a significant amount of process monitoring sensors to enable automated in-process checks and quality measurement.

Traditionally, the role of the tooling designer has been to identify the optimum tooling configuration for a given product design and its assembly. This frequently leads to complex dedicated tooling with extremely high build costs and long lead times. Current efforts within the aerospace industry are focussed towards a philosophy of minimising or eliminating dedicated tooling, known as “Jigless Manufacture”. To facilitate this, it is advantageous for product designers to have support from a product modelling environment, which enables components to be designed to take full advantage of jigless principles and enabling technologies. The purpose of this paper is to outline an assembly modelling and analysis framework as part of an product modelling environment to support the jigless manufacture philosophy.