Showing papers by "Saab Automobile AB published in 2009"

eMaintenance-Information logistics for maintenance support

Abstract: Today's providers of maintenance and in-service support related to modern aircraft are facing major challenges. A central problem with Maintenance, Repair and Overhaul (MRO) as well as support of aircraft and other complex technical systems, is to manage the ever-increasing information flow and system complexity. Both military and commercial operators need to reduce aircraft downtime and maintenance man hours. Increased manual information management has the opposite effect, inducing unnecessary cost and affect efficiency negatively. Organizations developing and providing maintenance support products and in-service support does also need to improve the capability to efficiently exploit the increasing amount of digital product information and design data provided together with hardware (HW) and software (SW) products from aircraft manufacturers, sub-system suppliers and Original Equipment Manufacturers (OEM). One way to increase aircraft availability and improve maintenance and support efficiency, is to speed up the turnaround time for scheduled and unscheduled maintenance. The ultimate goal is risk-based utilization and support, where true Condition-Based Maintenance (CBM) is integrated with current operational requirements and available resources in real-time. This aims at the elimination of all preventive scheduled maintenance based on fixed time intervals and execution of only corrective maintenance that has been predicted and turned into scheduled maintenance facilitated by proper support. To address the challenge of information logistics of digital product data and information within maintenance in-service support, providers need to adapt new methodologies and tools that enable full utilization of the advantages of digital product data and information in processes and business models, e.g., Service-Oriented Architecture (SOA). To implement such improved support solutions in a global-support environment, eMaintenance is seen as one important building block. eMaintenance includes monitoring, collection, recording and distribution of real-time system health data, maintenance-generated data as well as other decision and performance-support information to different stakeholders independent of organization or geographical location, 24h a day, 7 days a week (24/7). eMaintenance has the potential to improve the management and performance of activities related to the whole maintenance process, and thereby improve the dependability, safety and Life Cycle Cost (LCC) of critical systems. This can be realized through a coordinated application of Information and Communication Technology (ICT) throughout the maintenance and support processes, thus integrating Built-in Test (BIT) systems, external tests at different maintenance echelons, technical information, diagnostics, prognostics and other sources of support information. The purpose of this paper is to present some results from a joint academic and aerospace industry research project, describing requirements and expectations that are important in a global-support environment, and also to propose some central components in an eMaintenance framework that integrates maintenance and ICT perspectives.

Influence of temperature and strain rate on cohesive properties of a structural epoxy adhesive

Abstract: Effects of temperature and strain rate on the cohesive relation for an engineering epoxy adhesive are studied experimentally. Two parameters of the cohesive laws are given special attention: the fracture energy and the peak stress. Temperature experiments are performed in peel mode using the double cantilever beam specimen. The temperature varies from −40 to + 80°C. The temperature experiments show monotonically decreasing peak stress with increasing temperature from about 50 MPa at −40°C to about 10 MPa at + 80°C. The fracture energy is shown to be relatively insensitive to the variation in temperature. Strain rate experiments are performed in peel mode using the double cantilever beam specimen and in shear mode, using the end notch flexure specimen. The strain rates vary; for peel loading from about 10−4 to 10 s−1 and for shear loading from 10−3 to 1 s−1. In the peel mode, the fracture energy increases slightly with increasing strain rate; in shear mode, the fracture energy decreases. The peak stresses in the peel and shear mode both increase with increasing strain rate. In peel mode, only minor effects of plasticity are expected while in shear mode, the adhesive experiences large dissipation through plasticity. Rate dependent plasticity, may explain the differences in influence of strain rate on fracture energy between the peel mode and the shear mode.

Marginalized Particle Filter for Accurate and Reliable Terrain-Aided Navigation

Abstract: This paper details an approach to the integration of INS (inertial navigation system) and TAP (terrain-aided positioning). The solution is characterized by a joint design of INS and TAP, meaning that the highly nonlinear TAP is not designed separately but jointly with the INS using one and the same filter. The applied filter extends the theory of the MPF (marginalized particle filter) given by. The key idea with MPF is to estimate the nonlinear part using the particle filter (PF), and the part which is linear, conditional upon the nonlinear part, is estimated using the Kalman filter. The extension lies in the possibility to deal with a third multimodal part, where the discrete mode variable is also estimated jointly with the linear and nonlinear parts. Conditionally upon the mode and the nonlinear part, the resulting subsystem is linear and estimated using the Kalman filter. Given the nonlinear motion equations which the INS uses to compute navigation data, the INS equations must be linearized for the MPF to work. A set of linearized equations is derived and the linearization errors are shown to be insignificant with respect to the final result. Simulations are performed and the result indicates near-optimal accuracy when compared with the Cramer-Rao lower bound.

A computerized optimization framework for the morphological matrix applied to aircraft conceptual design

Abstract: This paper presents a formal mathematical framework for the use of the morphological matrix in a computerized conceptual design framework. Within the presented framework, the matrix is quantified so that each solution principle is associated with a set of characteristics such as weight, cost, performance, etc. Selection of individual solutions is modeled with decision variables and an optimization problem is formulated. The applications are the conceptual design of subsystems for an Unmanned Aerial Vehicle and an aircraft fuel transfer system. Both the system models and the mathematical framework are implemented in MS Excel.

Comparison of Antenna Measurement Facilities With the DTU-ESA 12 GHz Validation Standard Antenna Within the EU Antenna Centre of Excellence

Abstract: The primary objective of many antenna measurement facilities is to provide a specified high accuracy of the measured data. The validation of an antenna measurement facility is the process of proving that such a specified accuracy can be achieved. Since this constitutes a very challenging task, antenna measurement accuracy has been the subject of much research over many years and a range of useful measures have been introduced. Facility comparisons, together with antenna standards, error budgets, facility accreditations, and measurement procedure standards, constitute an effective measure towards facility validations. This paper documents the results of a comparison between 8 European antenna measurement facilities with a specially designed reference antenna, the DTU-ESA 12 GHz validation standard antenna (VAST-12). The electrical and mechanical properties of the VAST-12 antenna are presented and its three different coordinate systems are defined. The primary objective of the comparison is to obtain experience and results that can serve to develop standards for validation of antenna measurement facilities. The paper focuses on the comparison of the radiation pattern and presents not only the measurement data obtained at the facilities, but also investigates several procedures for comparing these data. This includes various definitions of pattern difference and statistical measures as well as a reference pattern. The comparison took place in 2004-2005 as part of the European Union network of excellence called ACE-Antenna Centre of Excellence.

Application of a line-implicit scheme on stretched unstructured grids

Abstract: A line-implicit Runge-Kutta time stepping scheme is derived, implemented and applied. It is applied to fluid flow problems governed by the Navier-Stokes equations on stretched unstructured grids. The flow equations are integrated implicitly in time along structured lines in regions where the grid is stretched, typically in the boundary layer, and explicitly elsewhere. The integration technique is introduced for steady state problems with the intention to speed up the rate of convergence. It is extended to unsteady problems by a dual time stepping approach. The paper focuses on the implementation of the line-implicit scheme starting from an explicit multigrid flow solver and on the application of it. Numerical results are presented for test cases in two and three dimensions for inviscid and viscous flow problems. The line-implicit time integration convergence rates are compared to pure explicit convergence rates and the gain is quantified in terms of reduction of iterations and CPU time. All presented test cases show improved convergence rates. The gain is highest for the three dimensional test cases for which reductions of up to 75% of the computing time is obtained.

Side lobe suppression

Abstract: Embodiments include a method to suppress side lobes of a main antenna by creating cancellation directions using a Side Lobe Canceller (SLC) Various embodiments also provide the Side Lobe Canceller

Photonic scanning receiver using an electrically tuned fiber Bragg grating

Abstract: A 5-cm-long electrically tuned fiber Bragg grating is used to filter a microwave signal on an optical carrier at 1.55 mum. A chirped distributed-feedback structure is employed, with a transmission bandwidth of 54 MHz and relative optical carrier rejection of >30 dB for rf frequencies >2 GHz. The rapid monotonic sweep of the Bragg wavelength is translated into a fast-frequency sweep for rf analysis.

A Single Polarized Triangular Grid Tapered-Slot Array Antenna

Abstract: A triangular grid single polarized tapered-slot array antenna for radar applications is studied. Compared with a rectangular grid an equilateral triangular grid allows a larger unit cell without any onset of grating lobes. Since single polarized tapered-slots in triangular grids support guided modes, which cause scan blindness, the increase in unit cell size is smaller than the optimal 15%. The design presented in the paper is capable of scan angles out to 60° from broadside in the E and H planes. To improve the match over the radar band a local minimum in the active reflection coefficient is positioned at the most critical scan direction, resulting in a reflection coefficient that is less than -12 dB in the X-band. To reduce the radar cross section for the cross-polarization an absorbing layer is positioned above the ground plane, which affects some of the guided modes that lead to scan blindnesses. An experimental antenna with 16 × 16 elements was built, and it was found that the H-plane performance for large scan angles for the finite antenna deviates more than expected from the infinite array approximation. Otherwise both mutual coupling measurements and embedded element patterns agrees well with the numerical results.

Development of ICT‐based maintenance support services

Abstract: Purpose – The purpose of this paper is to describe a taxonomy for an eMaintenance management framework (eMMF) based on a service‐oriented approach, in order to facilitate the development of information and communication technology (ICT)‐based maintenance support services aimed at actors within the maintenance process related to complex technical industrial systems.Design/methodology/approach – To fulfil this purpose, a case study of a modern multi‐role combat aircraft is selected as an appropriate research strategy and supported by a literature study. Empirical data are collected through interviews, workshops, document studies, and observations. A framework is developed and evaluated using a prototype within the studied case. The study is performed in close cooperation with the aircraft's type certificate holder and the customer representative and operator in one country.Findings – The proposed eMMF aids in the identification and development of ICT‐based maintenance support services tailored for specific ...

VISAD: an interactive and visual analytical tool for the detection of behavioral anomalies in maritime traffic data

Abstract: Monitoring the surveillance of large sea areas normally involves the analysis of huge quantities of heterogeneous data from multiple sources (radars, cameras, automatic identification systems, reports, etc.). The rapid identification of anomalous behavior or any threat activity in the data is an important objective for enabling homeland security. While it is worth acknowledging that many existing mining applications support identification of anomalous behavior, autonomous anomaly detection systems are rarely used in the real world. There are two main reasons: (1) the detection of anomalous behavior is normally not a well-defined and structured problem and therefore, automatic data mining approaches do not work well and (2) the difficulties that these systems have regarding the representation and employment of the prior knowledge that the users bring to their tasks. In order to overcome these limitations, we believe that human involvement in the entire discovery process is crucial. Using a visual analytics process model as a framework, we present VISAD: an interactive, visual knowledge discovery tool for supporting the detection and identification of anomalous behavior in maritime traffic data. VISAD supports the insertion of human expert knowledge in (1) the preparation of the system, (2) the establishment of the normal picture and (3) in the actual detection of rare events. For each of these three modules, VISAD implements different layers of data mining, visualization and interaction techniques. Thus, the detection procedure becomes transparent to the user, which increases his/her confidence and trust in the system and overall, in the whole discovery process.

Integration of RCM and PHM for the next generation of aircraft

Abstract: With global cuts in defense budgets, air forces have to sustain the same level of readiness with a reduced number of aircraft. To succeed with this challenge, it is not sufficient to improve current maintenance concepts, but also new ones have to be introduced.

Poster abstract: Exploiting the LQI variance for rapid channel quality assessment

Abstract: Communicating over a reliable radio channel is vital for an efficient resource usage in sensor networks: a bad radio channel can lead to poor application performance and higher energy consumption. Previous research has shown that the LQI mean value is a good estimator of the link quality. Nevertheless, due to its high variance, many packets are needed to obtain a reliable estimation. Based on experimental results, we show instead that the LQI variance is not a limitation. We show that the variance of the LQI can be used as a metric for a rapid channel quality assessment. Our initial results indicate that identifying good channels using the LQI variance requires an order of magnitude fewer packets than when using the mean LQI.

Signature-based activity detection based on Bayesian networks acquired from expert knowledge

Abstract: The maritime industry is experiencing one of its longest and fastest periods of growth. Hence, the global maritime surveillance capacity is in a great need of growth as well. The detection of vessel activity is an important objective of the civil security domain. Detecting vessel activity may become problematic if audit data is uncertain. This paper aims to investigate if Bayesian networks acquired from expert knowledge can detect activities with a signature-based detection approach. For this, a maritime pilot-boat scenario has been identified with a domain expert. Each of the scenario's activities has been divided up into signatures where each signature relates to a specific Bayesian network information node. The signatures were implemented to find evidences for the Bayesian network information nodes. AIS-data with real world observations have been used for testing, which have shown that it is possible to detect the maritime pilot-boat scenario based on the taken approach.

The Matrix Balun—A Transistor-Based Module for Broadband Applications

Abstract: In this paper the analysis and design of a new active balun with very broadband performance, the matrix balun, are reported. Measured results show a common mode rejection ratio, CMRR, larger than 15 dB between 4 and 42 GHz while exhibiting 2 dB single-ended gain with a ripple of 1 dB. The balun was realized in a 0.15 mum GaAs mHEMT process. It occupies a chip area of 0.63 mm2 and consumes a dc power of 20 mW. The same matrix balun circuit may also be biased for amplification and used as a matrix amplifier. The circuit then exhibits 10.5 dB gain up to 63 GHz with 1 dB ripple above 5.5 GHz and a power consumption of 67 mW.

Reasoning about anomalies: a study of the analytical process of detecting and identifying anomalous behavior in maritime traffic data

Abstract: The goal of visual analytical tools is to support the analytical reasoning process, maximizing human perceptual, understanding and reasoning capabilities in complex and dynamic situations. Visual a ...

Estimation of Real-Time Software Code Size using COSMIC FSM

Abstract: For distributed networks which will be mass produced, such as computer systems in modern vehicles, it is crucial to find cost efficient hardware. A distributed network in a vehicle consists of several ECUs (Electronic Control Unit). In this paper we consider the amount of memory needed for these ECUs. They should contain enough memory to survive several software generations, without inducing unnecessary cost of too much memory. Our earlier work shows that UML Component Diagrams can be used to collect enough information for estimating memory size using a Functional Size Measurement method. This paper replicates our earlier experiment with more software components of a different type. We compare the results from the two experiments.

SMARTracIn: a concept for spoof resistant tracking of vessels and detection of adverse intentions

Abstract: The aim of maritime surveillance systems is to detect threats early enough to take appropriate actions. We present the results of a study on maritime domain awareness performed during the fall of 2008. We analyze an identified capability gap of worldwide surveillance in the maritime domain, and report from a user workshop addressing the identified gap. We describe a SMARTracIn concept system that integrates information from surveillance systems with background knowledge on normal conditions to help users detect and visualize anomalies in vessel traffic. Land-based systems that cover the coastal waters as well as airborne, space-borne and ships covering open sea are considered. Sensor data are combined with intelligence information from ship reporting systems and databases. We describe how information fusion, anomaly detection and semantic technology can be used to help users achieve more detailed maritime domain awareness. Human operators are a vital part of this system and should be active components in the fusion process. We focus on the problem of detecting anomalous behavior in ocean-going traffic, and a room and door segmentation concept to achieve this. This requires the ability to identify vessels that enter into areas covered by sensors as well as the use of information management systems that allow us to quickly find all relevant information.

Enhanced situational awareness in the maritime domain: an agent-based approach for situation management

Abstract: Maritime Domain Awareness is important for both civilian and military applications. An important part of MDA is detection of unusual vessel activities such as piracy, smuggling, poaching, collisions, etc. Today's interconnected sensorsystems provide us with huge amounts of information over large geographical areas which can make the operators reach their cognitive capacity and start to miss important events. We propose and agent-based situation management system that automatically analyse sensor information to detect unusual activity and anomalies. The system combines knowledge-based detection with data-driven anomaly detection. The system is evaluated using information from both radar and AIS sensors.

Modeling and simulation of Saab Gripen’s vehicle systems

Abstract: This paper gives an overview of the modeling and simulation work for the military aircraft JAS 39 Gripens vehicle systems. The vehicle systems comprise fuel, ECS, hydraulic, and auxiliary power systems and also landing gear. Vehicle systems have several modeling challenges such as both compressible air and less compressible fluids that give stiff differential equations, g-force effects, nonlinear cavitation and saturation. It is also a complex system of integrated systems that requires models with integrated system software. Dynamic models based on physical differential equations have generally been used. The physical systems were previously modeled in Easy5 and the software in MATRIXx. Changes in tools where the physical systems are modeled in Dymola and the control algorithms are modeled in Simulink have opened up for new possibilities for more advanced and more complete system simulations. Simulations have been performed during the whole development cycle of the aircraft from concept evaluation to qualification tests. The paper gives some examples from the simulations where system performance and the internal states of the system are calculated.

Collaborative Command and Control Practice: Adaptation, Self-Regulation and Supporting Behavior

Abstract: This thesis concerns command and control (C2) work at the tactical level in emergency and crisis response operations. The presented research addresses two main research questions. The first question is whether it is feasible to simulate and study C2 work in the initial stages of response operations by means of role-playing simulations. If so, the second question is how to develop and execute role-playing simulations in order to explore this type of C2 work in a methodologically sound way. The presented research is based on simulations as methodological means for qualitative research. The utilized simulation approach is scenario-based real-time role-playing simulations grounded in models of C2 work and response operations. Three simulations have been conducted based on this methodology and are reported in this thesis. Simulation I focused on the work practice of cooperating commanders whose activities may be enhanced by the use of artifacts. Simulation II concerned the issues of operationalizing advanced technological artifacts in rapid response expert teams. Simulation III gave attention to the role improvisation in C2 teams designated for international operations. The results from the simulations and from the work conducted and presented in this thesis contribute with knowledge and experience from using role-playing simulations to study C2 work. This includes the methodological aspects of designing and conducting role-playing simulations such as scenarios, realism, evaluation and simulation format and control. It also includes the identification of the main application and problem areas for which the methodology is suitable, that is explorative qualitative inquiries and evaluation studies. The thesis provides new insights in C2 work with respect to adaptive behavior and improvisation. The thesis also identifies areas that need to be considered in order to further develop the role-playing simulation approach and its applicability.

Modelling manufacturing tolerances in 1–18 GHz double-ridged horn antennas

Abstract: The effect of small gaps in the feeding section of a 1–18 GHz broadband double-ridged horn antenna is investigated. It is shown how poor design, assembly or manufacturing tolerances can lead to a dramatic loss in the performance of this type of horn antenna. The gaps are implemented in a highly accurate broadband simulation model of the antenna that includes the coaxial feeding section as well as the N-type connector. The model is implemented in the electromagnetic simulation software package FEKO, which uses the method of moments technique to calculate the electromagnetic fields. Excellent agreement between measured and simulated data is obtained. This study shows the extreme sensitivity of the traditional 1–18 GHz horn's feeding structure.

Trainee Evaluation Through After-action Review by Comparison

Abstract: We describe an investigation into how to automate after-action review (AAR) to provide non-trivial, individual feedback to trainees in a military training context. On a high-level basis, our approach is to monitor the actions of the trainee(s) and compare them with those of software agents (called expert agents) whose behavior represents that of an expert-level performer. By identifying and logging discrepancies between the trainee and the expert agent, a measure of valuable feedback can be given to the trainee to whom the expert agent was assigned to ‘shadow’. The comparisons are made in two dimensions concurrently: the physical dimension and the tactical dimension. In a physical comparison, the trainee is compared with the physical location of the expert agent. In the tactical comparison, the context of the agent is compared with that of the trainee. If the latter comparison agrees, then it can be said that the trainee is employing the same tactics as the agent. The context of the trainee is un-intrusiv...

An appearance-based measure of surface defects

Abstract: Surface defects on sheet metal panels such as local out-of-plane geometric deviations, cause unwanted deviations from the intended visual appearance. In the automobile industry, these defects are commonly graded for visual acceptability through reflection analysis on the hardware. This widely used method is unfortunately subjective and thus has low repeatability. The same method can be applied on simulated sheet metal panels by the use of ray-tracing. In this paper we present an objective, appearance-based, measure by formalising the approach of subjective reflection analysis. Hence, a natural connection between an objective measure and the appearance is obtained making it easy to establish acceptable levels. The performance of this measure and three other objective measures is discussed and demonstrated for a real panel and a panel geometry obtained through sheet forming simulations. These examples illustrate that different measures yield different information about the geometry, and the proposed measure gives a useful quantification of the visual appearance deviation.

No fault found events during the operational life of military aircraft items

Abstract: No Fault Found (NFF) events are critical and well-known problems for certain aircraft items. This paper presents a study of these events for repairable items with on-condition maintenance, based on operational data from a military aircraft. Some findings are that: the number of NFF events is influenced by item type and number of repairs; most NFF events are initiated by faults recognized during operation; and different inspections contribute to NFF events. Hence, item design and tests at different operational modes and maintenance echelons should be better aligned to reduce the number of NFF events.

Snag free reversible camouflage netting

Abstract: A camouflage construction comprises a first base layer having a top side defining a first camouflage motif and an opposite bottom side defining a second camouflage motif. A second garnish layer, formed from a plurality of elongated strips each having a central longitudinal axis extending between opposite ends of each strip, and a plurality of slits formed transverse to each strip longitudinal axis so that a plurality of fingers are formed on each side of the longitudinal axis so that each finger has a first end that is attached to a continuous central portion of the strip and a second end that is free to move with respect to the first end and adjacent fingers, are bonded to the first base layer top side along the central longitudinal axes to form a three-dimensional motif on the first base layer top side.