Improving Working Conditions in Aircraft Productions using Human-Robot-Collaboration in a Collaborative Riveting Process

<div class="section abstract"><div class="htmlview paragraph">In large scale industries attempts are continuously being made to automate assembly processes to not only increase productivity but also alleviate non-ergonomic tasks. However this is not always technologically possible due to specific joining challenges and the high number of special-purpose parts. For the riveting process, for example, semi-automated approaches represent an alternative to optimizing aircraft assembly and to reduce the exposure of workers to non-ergonomic conditions entailed by performing repetitive tasks.</div><div class="htmlview paragraph">In [<span class="xref">1</span>], a semi-automated solution is proposed for the riveting process of assembling the section barrel of the aft section to its pressure bulkhead. The method introduced a dynamic task sharing strategy between human and robot that implements interaction possibilities to establish a communication between a human and a robot in Human-Robot-collaboration fashion. Although intuitive, interacting with the robot constantly is still not natural for the worker as in the manual process no explicit communication between both workers is needed.</div><div class="htmlview paragraph">In this work a communication-free Human-Robot-collaboration solution is presented. The method developed not only enables sharing assembly missions by dividing tasks based on skills, but also offers the possibility of decision making to the robot. In this context, off-the-shelf Artificial Intelligence planning tools are used to model the work-flow of the human as well as the task of the robot handling alongside possible uncertainties yielding while perceiving the environment or the activity of the human.</div></div>

<div class="section abstract"><div class="htmlview paragraph">The automation of assembly processes in aircraft production is, due to technological and organizational boundary conditions, very difficult and is subject to technological challenges and economical risks. The technological challenges are especially the large product dimensions as well as the high amount of variants. At the same time, aircrafts are produced in low quantities with inflexible and expensive fixtures.</div><div class="htmlview paragraph">As part of the research projects TRSE (semi-automated robot welding for single item production) and 4by3 (Modularity, Safety, Usability, Efficiency by Human-Robot-Collaboration) at ZeMA, the goal is to develop new process technologies, planning tools and adequate equipment in order to enable efficient and customized automation for various production processes.</div><div class="htmlview paragraph">The human-robot-cooperation is an approach to a required, adjusted and flexible automation. Worker and robot work together without a separating protection device in an overlapping workspace.</div><div class="htmlview paragraph">The idea is to support the worker in the production process with a sensitive robot to achieve a higher process efficiency and an improvement of quality.</div></div>

<div class="section abstract"><div class="htmlview paragraph">Developing the most advanced wing panel assembly line for very high production rates required an innovative and integrated solution, relying on the latest technologies in the industry.</div><div class="htmlview paragraph">Looking back at over five decades of commercial aircraft assembly, a clear and singular vision of a fully integrated solution was defined for the new panel production line. The execution was to be focused on co-developing the automation, tooling, material handling and facilities while limiting the number of parties involved. Using the latest technologies in all these areas also required a development plan, which included pre-qualification at all stages of the system development.</div><div class="htmlview paragraph">Planning this large scale project included goals not only for the final solution but for the development and implementation stages as well.</div><div class="htmlview paragraph">The results: <ul class="list disc"><li class="list-item"><div class="htmlview paragraph">Design/build philosophy reduced project time and the number of teams involved. This allowed for easier communication and extended development time well into the project.</div></li><li class="list-item"><div class="htmlview paragraph">All design teams (machine, tooling, automation, controls) collocated and worked together on integration during all stages of development and implementation for the highest level of integration.</div></li><li class="list-item"><div class="htmlview paragraph">Innovative integration of the tooling and the automated equipment evolved throughout project with the teams working as one group.</div></li><li class="list-item"><div class="htmlview paragraph">Latest fastening technology using all electric, ball-screw squeeze riveting was developed for high-speed and robust automated fastening.</div></li><li class="list-item"><div class="htmlview paragraph">Latest mobilization technology was used to make the automated fastening machines interchangeable to reduce MTTR and to enable more PPM activities offline without affecting production.</div></li><li class="list-item"><div class="htmlview paragraph">More automation was also introduced for tool changing and to the material handling systems for more consistent processing and to reduce operator intervention.</div></li><li class="list-item"><div class="htmlview paragraph">All systems were developed together for full integration and to enable more safety interlocks and HMI for simplified operation.</div></li><li class="list-item"><div class="htmlview paragraph">A 30 month schedule for the complete large scale assembly line was maintained to support the new aircraft launch schedule.</div></li></ul></div><div class="htmlview paragraph">The final solution was a coherent, streamlined and efficient assembly line capable of very high aircraft production rates (<span class="xref">Figure 1</span>).</div><div class="htmlview paragraph"><figure id="F1" class="figure"><div class="graphic-wrapper"><img class="article-figure figure" src="2015-01-2492_fig0001.jpg" alt="PAL, automation cell, Line 4, Position 1 (L4P1)"/></div><span class="label">Figure 1</span><figcaption class="caption"><span class="title">PAL, automation cell, Line 4, Position 1 (L4P1)</span></figcaption></figure></div></div>

<div class="section abstract"><div class="htmlview paragraph">Avcorp Industries Inc. recognized the need to reduce assembly labor costs in order to stay competitive with global competition. After two years of research and investigation it was determined that a joint project with Dassault Aviation provided the most viable solution.</div><div class="htmlview paragraph">The key elements of the technology developed by Dassault were its high flexibility and rapid payback of capital investment.</div><div class="htmlview paragraph">This paper describes the system and the application. The structure’s design and robotic system design were performed in parallel. A number of design challenges had to be overcome. Many of these issues encountered were common to any automated assembly application. By covering these challenges Avcorp was able to introduce automated assembly at a level that had typically been previously attained exclusively by much larger enterprises.</div><div class="htmlview paragraph">The robotic system consists of two anthropomorphic robots, which work both individually and in tandem. The operations performed include drilling, countersinking, sealant application, cleco insertion, as well as the installation of blind fasteners, solid fasteners and hi-lites. This system is currently performing integration tests and will enter production in fourth quarter 1999. Development testing has substantiated our estimates concerning cost reduction and quality enhancement.</div></div>

<div class="htmlview paragraph">The performance of a parking system is dependent on many factors. One is the placement of the sensors. In this paper a system which uses ultrasonic ranging sensors is considered. The mounting of a ultrasonic sensor on a passenger vehicle is restricted by, among other factors, design, assembly process, enclosure cost and reliability. All of which must be considered when choosing optimal mounting locations.</div> <div class="htmlview paragraph">The basis of this work includes a ray-trace based simulation environment which is used to capture the physical properties of sound traveling through air. The simulation environment together with sensor models, is used to evaluate the effect of different mounting positions on the accuracy of the detection of the parking space. The Hough transform is used here, as well as in the real system, in order to extract the confining lines of the parking space from the sensor measurements. The strength of these lines are then used to compare different sensor mounting locations.</div> <div class="htmlview paragraph">The created simulation environment differs from other work in this area since it tries to capture the <i>physical</i> properties of the sound waves as opposed to the geometric-only approach. The emitted sound pulse is divided into a large number of rays, each with sound properties tied to them. These rays are then traced through a model of the parking space environment, reflections are calculated and finally the summarized echo into the listening sensor is calculated.</div> <div class="htmlview paragraph">The simulation is implemented in 3D Studio MAX which make it relatively easy to create various realistic parking scenarios. An important factor for choosing 3D Studio MAX as the basis of the simulation environment was that it allowed for a new way of modeling ultrasonics using ray-tracing, and at the same time - using the same ray-tracing technology - excellent visualization capabilities.</div> <div class="htmlview paragraph"> <figure id="F1" class="figure"> <div class="graphic-wrapper"><img class="article-figure figure" src="2007-01-1103_fig0001.jpg" alt="No Caption Available"/></div> </figure> </div>

Riveting is the most common method of assembling sheet metal parts which are widely used in the assembly of aircraft and other areas. The rivet can be divided into two types: manual and automatic. There are many parameters associated with a riveting process that directly affect the quality of rivets including squeeze force, rivet length, rivet diameter, and hole diameter tolerance. So its very important that each component of a rivet has high reliability and precision to ensure the stability during the riveting process. This paper reviews various recent patents in the key components of both types of rivets and various applications. The patents reviewed concern a period extending from the years 2000 up to date. The applications concern mainly both types of integrated rivets covering the area connected with the production of aircraft, auto and other industrial mechanism using modernization that has reached by material replacing, geometry, and embedding additional units into main design The list of patents reviewed is by no means complete or extensive it shows however the extent of the subjects covered in patents in this area during the last five years. The paper concludes with a description of the future developments expected in the subjects covered. Keywords: Rivet, riveting process, electromagnetic riveting, self piecing riveting, creep

<div class="htmlview paragraph">The new elastohydrodynamic (EHD) code developed by FEV Motorentechnik GmbH, Aachen, is designed to improve the predictability of journal bearing designs and thereby increase the reliability of safety factors in the development of highly loaded internal combustion engines. Using this tool design targets can be achieved with higher confidence levels.</div> <div class="htmlview paragraph">The developed code may be linked to commercial multibody system (MBS) codes such as ADAMS<sup>®</sup> while simultaneously representing the important characteristics occurring in transiently loaded journal bearings including elastic deformation, cavitation, and non-constant speed. Static deviations from ideal journal and bearing shell shapes caused by manufacturing and assembly processes can be considered and are substantially important in the evaluation of journal bearings.</div> <div class="htmlview paragraph">Presented is an economic bearing model approach which includes elastic bearing deformations. Only a few hours of calculation time are needed to reach steady state conditions on a standard workstation.</div>

<div class="section abstract"><div class="htmlview paragraph">This paper summarizes the outcome of an evaluation by capstone design teams from the Department of Mechanical and Materials Engineering at the University of Nebraska-Lincoln, of the Ecosystem for Design Assessment and Verification. The Ecosystem is a design decision support tool whose main goal is to identify design oversights, defined in terms of deviations from the design process or unfulfilled design requirements, early in the design process, guide designers through the design process, and teach proper design techniques. It is capable of automatically assessing students’ design work against ABET compliant learning outcomes. The Ecosystem offers many additional features found useful by capstone design teams, such as automatic generation of formatted project reports as well as interfaces to tools for team communications (Google Drive, Dropbox or OneDrive) or development (e.g., SolidWorks, CATIA, NX Unigraphics or AutoCAD).</div><div class="htmlview paragraph">The Ecosystem was recently evaluated by a capstone team working on an automated straw flattening machine and again during a following semester by a team designing a dynamometer used for measuring the engine power of a BAJA race car.</div><div class="htmlview paragraph">The paper draws upon the improvements of the Ecosystem software completed during the aforementioned time period, identifies the features the capstone teams found most useful, and compares the design experience (productivity) of the BAJA Dynamometer team to that of the a team not using the Ecosystem, but with the same faculty adviser. Through comparison of two such teams, it was found that the team using the Ecosystem managed to stay on schedule a little better.</div></div>

<div class="htmlview paragraph">Automobiles from all parts of the world are now being built with plastic fuel tanks made from high density polyethylene (HPDE). The most difficult aspect of the current manufacturing process for meeting environmental regulations is the need to work with hazardous chemicals such as fluorine and sulfur trioxide to reduce hydrocarbon permeation.</div> <div class="htmlview paragraph">Laminar barrier technology is a barrier process under development which meets EPA requirements, reduces costs and eliminates environmental and employee safety concerns. Laminar technology is a patented, one-step barrier process where 4-5% of a barrier resin is dry blended with HDPE and processed using standard blow molding equipment. The finished fuel tank will contain an integral barrier composed of overlapping barrier resin platelets within the HDPE matrix. Regrind can be effectively utilized and there are no restrictions for secondary assembly techniques such as hot plate welding.</div> <div class="htmlview paragraph">Barrier properties of a lamellar fuel tank can be instantaneously quantified using a non-destructive quality control test. This is a new Q.C. test for fuel tanks that will allow the barrier effectiveness of every tank produced to be verified.</div> <div class="htmlview paragraph">It is anticipated that laminar barrier technology will provide a more flexible process to further accelerate the trend toward plastic fuel tanks including tanks with better barrier to alcohol fuel blends. All processing and performance requirements have been met worldwide.</div>

<div class="section abstract"><div class="htmlview paragraph">The lithium ion battery is one of the key technologies of electric and hybrid vehicles. Though the electric vehicles pose a promising solution to conventional vehicles, the high cost and weight of the battery package makes the electric vehicle less competitive in the market. As the current researchers focus on making the battery pack more affordable, an approach can also be made in modularizing and speeding up the assembly process of these battery packs. Therefore, this paper focuses on achieving a smaller, lighter and less expensive battery pack suitable for global production using Design for Assembly (DFA) principle. The approach includes considering a battery pack of Audi Q5 as a case study and studying its assembly sequences. DFA principles would be applied to the assembly design, to simplify/reduce its components through part integration, and making recommendations to modularize the design so that similar assembly processes can be used for variety of battery requirements. The manufacturing cost of the proposed suggestions are not included in the paper due to lack of data available which therefore defined the scope of the study to introduce ideas that could be implemented to improve only assembly process using Boothroyd Dewhurst DFA method.</div></div>

<div class="section abstract"><div class="htmlview paragraph">As aircraft programs currently ramp up, productivity of assembly processes needs to be improved while keeping quality, reliability and manufacturing cost requirements. Efficiency of the drilling process still remains an issue particularly in the case of CFRP/metal stacks: hot and long metallic chips are difficult to remove and often damage the surface of CFRP holes.</div><div class="htmlview paragraph">Low frequency axial vibration drilling has been proposed to solve this issue. This innovative drilling process allows breaking up the metallic chips in such a way that jamming is avoided.</div><div class="htmlview paragraph">This paper presents a case of CFRP/Ti6Al4V drilling on a CNC machine where productivity must be increased. A comparison is made between the current regular process and the MITIS drilling process. First the analysis and comparison method is presented. The current process is analyzed and its limits are highlighted. Then the vibration process is implemented and its performances are studied. Both processes are compared according to the following criteria: chip morphology, thrust force, power consumption, tool life, cycle time, holes quality and manufacturing costs.</div><div class="htmlview paragraph">Results show that the vibration drilling process is more productive and reliable, while maintaining the quality as well as reducing manufacturing costs. The paper also shows that the vibration drilling allows simplifying cutting tool design and reducing lubrication.</div></div>

<div class="htmlview paragraph">This paper describes work being conducted by OC Robotics and Airbus to develop snake-arm robots to conduct assembly tasks within wing boxes - an area currently inaccessible for automation.</div> <div class="htmlview paragraph">The composite, single skin construction of aircraft structures presents new assembly challenges. Currently during box close-out it is necessary for aircraft fitters to climb into the wing box through small access panels and use manual or power tools to perform a variety of tasks. In future wing designs it may be that certain parts of the wing do not provide adequate access for manual assembly methods. It is also known that these manual interventions introduce health and safety concerns with their associated costs.</div> <div class="htmlview paragraph">Snake-arm robots provide a means to replace manual procedures by delivering the required tools to all areas of the wing box.</div> <div class="htmlview paragraph">Such a development has broader implications for aircraft design and assembly. There is potential for considerable cost savings for the aerospace industry through reduced weight, improved aerodynamics, standardisation of assembly processes, increased rate and reduced health and safety costs.</div> <div class="htmlview paragraph">This paper presents early results of the demonstration snake-arm robot and outlines expectations for future development. It also identifies critical design parameters for the snake-arm and considers the tools and processes delivered by the snake-arm.</div>

<div class="htmlview paragraph">Boeing's wholly owned subsidiary in Australia, Hawker de Havilland produces all ailerons for the Boeing 737 family of aircraft. Increasing production rates required to meet market demand drove the requirements for a new updated approach to assembly of these parts. Using lean principals, a pulsed flow line approach was developed. A component of this new line is the integration of a flexible robotic drilling/trimming system. The new robotic system is required to meet aggressive tack time targets with high levels of reliability.</div> <div class="htmlview paragraph">The selected system was built on a Kuka KR360-2 conventional articulated arm robot. A significant challenge of this project was the requirement for the process head to work efficiently on an aileron in an existing jig. As a result a new side-mounted drill and trim end effector was developed. Automated tool changers for both cutters and pressure foot assemblies eliminated the requirement for in- process manual intervention. The robot was also configured to allow safe operation in two opposing work zones. This permitted the robot to continue working while parts are loaded and unloaded from an adjacent cell, improving the overall cell efficiency.</div>

<div class="section abstract"><div class="htmlview paragraph">Due to rising emissions, electric aircraft may indeed become inevitable. With the increase in production of hybrid aircraft, due to such needs for reduced energy sources and increased storage systems, the importance of batteries will also increase in the near future. When selecting batteries, consideration must be given to their energy density, non-toxicity, weight and optimum operating temperature. The density of lithium in the liquid state is only half that of water and in the solid state it is the lightest metal. Furthermore, lithium has a tendency to give electrons and charge, thus making it an important choice for use in batteries and the focus of this study. In this study, a sum of 20 batteries in the form of 2 parallel, 10 series were investigated. The thermal performance of the batteries was studied under natural conditions. It was concluded that forced convection should be done instead of natural convection for C ratios 2 and 2.5, because natural convection proved inadequate.</div></div>

<div class="section abstract"> <div class="htmlview paragraph">This specification prescribes process requirements for batch processing of used, metal powder originating from an existing additive manufacturing process workflow for reuse in subsequent additive manufacturing of aerospace parts in non-closed loop additive manufacturing machines. Such powders may be pre-alloyed or commercially pure. This specification is not limited to a specific additive manufacturing process workflow as the originating source of material to be reused. It is intended to define those procedures and requirements necessary to achieve required cleanliness and performance of metal powder feedstock to be reintroduced into the same additive manufacturing process from which such powder originated. This specification is intended to be used in conjunction with relevant AMS powder specifications and AMS process specifications for additive manufacturing.</div> <div class="htmlview paragraph">Unless otherwise specified, powder prepared for reuse following this specification is intended to be conforming in physical and chemical attributes as defined by the originating virgin powder specification for the purposes of producing aerospace parts, providing equivalent characteristics and properties as specified by the corresponding AMS material specification.</div></div>