A Crawling Portable Robot for Drilling Operations in Large Air Frame Components

<div class="htmlview paragraph">High Speed Machining, or better yet High Velocity Machining is often chosen especially for new investments in manufacturing, at least when machining non-ferrous metals. This makes sense given the progress in machine spindle technology and the velocity with which the machine axes can travel.</div> <div class="htmlview paragraph">This in conjunction with advanced cutting material, particularly polycrystalline diamonds, substantially reduces main machining and non-production time.</div> <div class="htmlview paragraph">Different is the situation when machining ferrous metal. Cast iron, Carbon and allow steels as well as super alloys; all have their specific characteristics making it difficult to apply real high cutting speeds.</div> <div class="htmlview paragraph">Since it is either technologically not feasible and/or impractical because of an unfavorable price/performance ratio to apply cutting speeds close to those applicable for non-ferrous metals, other avenues have to be taken.</div> <div class="htmlview paragraph">Besides the cutting speed, attention has to be paid to minimizing machining time and optimizing the entire machining process. This is what is called “High Performance Machining (HPM)”.</div> <div class="htmlview paragraph">HPM does not necessarily require the acquisition of new machinery; the efforts go toward improving upon existing processes. The most promising and intriguing part of the process is the cutting tools systems, for they can easiest be adapted to specific applications. Furthermore, when the application drives the process it is the new cutting tool system that mostly determines the level of machining and manufacturing performance.</div>

<div class="section abstract"><div class="htmlview paragraph">The mountainous roads are rugged and complex, so that the driver can not make accurate judgments on dangerous road conditions. In addition, most heavy vehicles have characteristics of large weight and high center of gravity. The two factors above have caused most of the car accidents in mountain areas. A research shows that 90% of car accidents can be avoided if drivers can respond within 2-3 seconds before the accidents happen.</div><div class="htmlview paragraph">This paper proposes a speed warning scheme for heavy-duty vehicle over the horizon in mountainous area, which can give the drivers enough time to respond to the danger. In the early warning aspect, this system combines the front road information, the vehicle characteristics and real-time information obtained from the vehicle, calculates and forecasts the danger that may happen over the horizon ahead of time, and prompts the driver to control the vehicle speed. Compared to the road standard speed limit, the combination of the road information and characteristics of heavy vehicle itself can provide a more accurate and more useful safety warning speed limit. Results of hardware-in-the-loop simulation show that this system can effectively reduce the brake temperature in the downhill, prevent rollover in the curve, and improve the heavy vehicle driving safety.</div></div>

<div class="section abstract"><div class="htmlview paragraph">Industrial robots have been around since the 1960s and their introduction into the manufacturing industry has helped in automating otherwise repetitive and unsafe tasks, while also increasing the performance and productivity for the companies that adopted the technology. As the majority of industrial robotic arms are deployed in repetitive tasks, the pose accuracy is much less of a key driver for the majority of consumers (e.g. the automotive industry) than speed, payload, energy efficiency and unit cost. Consequently, manufacturers of industrial robots often quote repeatability as an indication of performance whilst the pose accuracy remains comparatively poor. Due to their lack in accuracy, robotic arms have seen slower adoption in the aerospace industry where high accuracy is of utmost importance. However if their accuracy could be improved, robots offer significant advantages, being comparatively inexpensive and more flexible than bespoke automation. Extensive research has been conducted in the area of improving robotic accuracy through re-calibration of the kinematic model. This approach is often highly complex, and seeks to optimise performance over the whole working volume or a portion thereof, rather than optimising performance of a particular task. In this paper, a method for iteratively teaching poses on a standard industrial robot is presented, and an investigation into the limits on the achievable pose accuracy and the required recalibration period is conducted. Through experimental work on a KUKA KR 240 R2900 ultra robot equipped with a drilling end-effector and measured in 3DoF using a laser tracker, it is demonstrated that the achievable accuracy approaches the stated repeatability of the robot. Finally, investigation results into the accuracy of the robot over short distances to allow small corrections to be applied from these taught poses to compensate for work-piece alignment or thermal effects are presented.</div></div>

<div class="htmlview paragraph">The paper details two phases of work completed by Airbus UK to create a standard deployment platform for robotic processes.</div> <div class="htmlview paragraph">The initial part of the paper focuses on an aerospace capability study developed to benchmark a number of robot models. The tests define absolute accuracies within full and restricted work envelopes, static and dynamic flexure, and temperature effects on the robot manipulator.</div> <div class="htmlview paragraph">The second part of the paper describes the development of an adaptive control process to accurately position singular or co-operating robots within a large working envelope. The solution is not dependent on complex software algorithms within the robot controller or restrictive laser metrology interfaces. The paper illustrates how a number of standard industrial products can be ‘fused together’ to provide a robust industrial solution.</div>

<div class="htmlview paragraph">Computer aided systems for performance evaluation of functional devices for passenger cars, such as engines or transmissions, have been applied for ten years. These systems generally consist of a large main frame computer or minicomputers for conducting a large number of complicated analyses. In the past, these computer aided systems were used for vehicle research and development since they were too expensive and sophisticated for use on the production line.</div> <div class="htmlview paragraph">Today, microcomputers with mass memory or personal computers are available at very low cost in comparison to conventional minicomputers. With many distributed microcomputers, we have developed a new test and control system for the engine production line. This system consists of (1) a microcomputer with a disk system for test data storage, (2) five personal computers for the man-machine system and data processing, and (3) microcomputers for real time control and data acquistion. These distributed micro and personal computers have been connected with standard interfaces. With this system we have achieved higher efficiency of inspection such as performance testing, quality control, and higher levels of the test analyses.</div>

<div class="htmlview paragraph">To maintain our position as metallic powder suppliers, it is necessary to implement a never-ending commitment of increased product quality and productivity. To achieve this goal, we must redirect our philosophy of quality control to one of quality assurance. Only then can quality be built into, and not merely tested into, the products we market.</div> <div class="htmlview paragraph">To achieve this result, a technique of statistical process and quality assurance ‘SQA’ must be introduced into the production environment. The rewards are significant so, let's do it right the first time!</div> <div class="htmlview paragraph">While many shy away from the use of statistical methods, these techniques can be simplified and easily understood at the shop floor level. Employees will have a new sense of quality and pride as they become part of a total proactive quality assurance program.</div>

<div class="htmlview paragraph">A Breadboard-Scale Aerobic Bioreactor (B-SAB) has been designed and integrated with the Kennedy Space Center's Biomass Production Chamber (BPC). The bioreactor utilizes a mixed microbial community to biodegrade inedible plant residues, a component of a Controlled Ecological Life Support System (CELSS) waste-stream. The continuously stirred tank reactor (120 L working volume) supports nutrient recycling and secondary food production experiments, and can process an influent with a solids loading as high as 50 g L<sup>-1</sup>. The volumetric oxygen mass transfer coefficient, k<sub>L</sub>a, is 0.013 s<sup>-1</sup>. Nutrient solution for BPC lettuce and wheat crops has been produced. Currently, B-SAB is supplying 80% of the nutrients for 10 m<sup>2</sup> of potato plants in a continuous production experiment.</div>

<div class="section abstract"><div class="htmlview paragraph">Vacuum suction cups are used as transforming handles in stamping lines, which are essential in developing automation and mechanization. However, the vacuum suction cup will crack due to fatigue or long-term operation or installation angle, which directly affects production productivity and safety. The better design will help increase the cups' service life. If the location of stress concentration can be predicted, this can prevent the occurrence of cracks in advance and effectively increase the service life. However, the traditional strain measurement technology cannot meet the requirements of tracking large-field stains and precise point tracking simultaneously in the same area, especially for stacking or narrow parts of the suction cups. The application must allow multiple measurements of hidden component strain information in different fields of view, which would add cost. In this study, a unique multi-camera three-dimensional digital image correlation (3D-DIC) system was designed and applied to measure the strain concentration of the suction cups while the cups were running the pulling progress. In this technique, a multiplexed quad-cameras DIC system which contains two sets of 3D-DIC system (4 cameras) with different field of view or different measurement directions enables simultaneous measurement of full-filed and hidden parts under the same calibration progress. The first two cameras built a sub-group of the 3D-DIC system, which was used to measure the local strain of the narrow or stacked prats. The other system was used to acquire the strain fields of the entire suction cup. In addition to the experimental test, the fatigue test to see the cracks appeared location. The results of DIC were compared to the fatigue data, and the DIC experimental data validated the crack location. This project aims to help designers and operators thoroughly understand the performance of vacuum cups by investigating the strain concentration and crack location.</div></div>

<div class="htmlview paragraph">Radio frequency identification (RFID) is an emerging and evolving technology that has great potential to significantly improve the flow of our factory floor, facilitate lean manufacturing, and reduce our overhead costs. A multi-disciplined team in Boeing is currently developing and testing an RFID-based system for the control and management of time-and-temperature sensitive (TATS) materials on the shop floor. The team has designed a system employing RFID tags on material packaging and readers at material storage units to automate the tracking of these materials into inventory and their consumption. This system will enable Boeing to optimize the supply chain and in-house inventory levels as well as automate the identification of expired materials. Additional benefits include the ability to automate material re-ordering with our vendors, reduce shortages, quickly locate recalled lots of materials, and warn of improperly located materials. In summary, RFID will provide total asset visibility to this process.</div>

<div class="htmlview paragraph">To solve the problem of pores in the weld bead of automotive axles, a study was made of the influence of various factors leading to the occurrence of porosity in steel joints welded by the robotic MIG/MAG process. Basically, the study focused on the influence the presence of a nitride-rich layer at the joint, the cleanliness of the surfaces to be welded, and the flow rate of the shielding gas. The results indicated that the presence of the nitride-rich layer generated by the plasma cutting process at the end of the tube corresponding to the base metal 1 significantly affected the resulting porosity in the weld bead. In addition to the experimental tests, practical tests were carried out on the shop floor in the axle production sector.</div>

<div class="section abstract"><div class="htmlview paragraph">This article characterises the special features of drilling of CFRP/Titanium and -Aluminium stacks. Simplified theoretic models will show how CFRP/Titanium stacks should be machined without scratches and burn marks contacting carbon. Low axial forces and smart chip removal technology are the main characteristics of the drilling tool technology, optimised to reach H8 quality in one shot operation.</div></div>

<div class="htmlview paragraph">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.</div>

<div class="htmlview paragraph">A semi-automatic fire protection system has been developed to reduce operator hazards, the cost of repair, and lost production time as a result of fires on large mobile machines. Research of military and industrial fire protection systems for mobile equipment has resulted in a hybrid prototype system that combines optical and thermal fire sensors, logic controls, self-monitoring circuits and an extinguishing system to meet rigorous demands imposed by off-road equipment. The amount and type of fire protection needed for a variety of equipment is explained and a decision analysis matrix provides guidelines and rating scales of fire protection necessary for large haulage trucks and other off-road equipment.</div>

<div class="htmlview paragraph">Existing laboratory facilities were inadequate to accomplish the test requirements of the wide-bodied transports. Expansion was required by the size of the structure and the advanced technology of the flight guidance and control system. The Douglas Aircraft Company's test laboratories have been relocated to a new Engineering Development Center providing a large, high-bay test hangar and ready access to an extensive digital and analog computer facility for data reduction and simulation. Additionally, Douglas has designed and built four large test machines with a fatigue loading capability of 1-1/2 million pounds and is applying advanced servo loading techniques to both the airplane structural proof test and fatigue test programs.</div>

<div class="htmlview paragraph">Many manufacturing business practices and information systems are still designed around paper documents. These systems create and track paper documents that travel through the course of manufacturing, ending in the archive cabinets. Technology advancement and affordability enable the delivery of the paperless shop promised over twenty years ago. However, reengineering of business practices is required to take full advantage of the technology and eliminate the barriers created by paper. The reengineering effort should challenge traditional doctrines and encompass processes that extend beyond the boundaries of the shop floor, such as Quality Assurance and Process Planning. Besides eliminating paperwork, such process reengineering may include improvements to the user interface, streamlining of processes for natural and continual flows, elimination of non-value added steps, empowerment of the workforce, consolidation of processes, and improvement of quality. Companies do not re-implement their business systems often, and should not miss the opportunity for quantum leaps in performance from eliminating the paper on the shop.</div>