Showing papers by "Saab Automobile AB published in 2010"

Influence of Layer Thickness on Cohesive Properties of an Epoxy-Based Adhesive—An Experimental Study

Abstract: Cohesive laws are determined for different layer thicknesses of an engineering adhesive. The shape of the cohesive law depends on the adhesive layer thickness. Of the two parameters of the cohesive law—the fracture energy and the strength—the fracture energy is more sensitive to thickness variation than the strength. The fracture energy in peel mode (Mode I) increases monotonically as the thickness is increased from 0.1 to about 1.0 mm. At an adhesive thickness of 1.5 mm, the fracture energy is slightly lower than for a 1.0 mm adhesive thickness, indicating a maximum between 1.0 and 1.5 mm. In shear mode (Mode II), the thickness dependence is not as strong, but an increasing trend in fracture energy with increasing adhesive thickness is evident. A slight decrease in strength with increasing adhesive thickness is found in both loading modes.

An Impulse Response Function for Evaluation of UWB SAR Imaging

Abstract: Based on analysis of a point target imaged by different synthetic aperture radar (SAR) systems, the commonly used impulse response function in SAR Imaging (IRF-SAR)-a two-dimensional (2-D) sinc function-is shown to be inappropriate for ultrawideband-ultrawidebeam (UWB) SAR systems utilizing a large fractional signal bandwidth and a wide antenna beamwidth. As a consequence, the applications of the 2-D sinc function such as image quality measurements and spatial resolution estimations are limited to narrowband-narrowbeam (NB) SAR systems exploiting a small fractional signal bandwidth and a narrow antenna beamwidth. In this paper, a more general IRF-SAR, which aims at UWB SAR systems, is derived with an assumption of flat two-dimensional (2-D) Fourier transform (FT) of a SAR image and called IRF-USAR. However, the derived IRF-USAR is also valid for NB SAR systems.

An X-Band AlGaN/GaN MMIC Receiver Front-End

Abstract: This letter presents an integrated AlGaN/GaN X-band receiver front-end. This is to the authors knowledge the first published results of an integrated AlGaN/GaN MMIC receiver front-end. The receiver uses an integrated SPDT switch to reduce size, weight and cost compared to circulator based transceiver front-ends. The integrated front-end has more than 13 dB of gain and a noise figure of 3.5 dB at 11 GHz.

HCCI Heat Release Data for Combustion Simulation, based on Results from a Turbocharged Multi Cylinder Engine

Abstract: When simulating homogenous charge compression ignition or HCCI using one-dimensional models it is important to have the right combustion parameters. When operating in HCCI the heat release parameters will have a high influence on the simulation result due to the rapid combustion rate, especially if the engine is turbocharged. In this paper an extensive testing data base is used for showing the combustion data from a turbocharged engine operating in HCCI mode. The experimental data cover a wide range, which span from 1000 rpm to 3000 rpm and engine loads between 100 kPa up to over 600 kPa indicated mean effective pressure in this engine speed range. The combustion data presented are: used combustion timing, combustion duration and heat release rate. The combustion timing follows the load and a trend line is presented that is used for engine simulation. The combustion duration in time is fairly constant at different load and engine speeds for the chosen combustion timings here. The heat release rate is fitted to a Wiebe function where the heat release parameter m is found. It is shown that this parameter m scale to the load and the presented trend line is used for simulating the heat release. When the engine is operated with negative valve overlap the mass flow is reduced through the engine. In an engine simulation the valve timings has to be estimated for different intake temperatures and boost pressure levels. By using the intake temperature at intake valve closing as a prediction tool for the temperature at top dead center, the exhaust valve closing timing can be estimated and will then follow the real test results closely as shown in a GT-Power simulation. The turbocharged test engine is an in-line four cylinder gasoline engine with a total displacement of 2.2 l. The engine is direct injected of spray-guided type. To achieve HCCI combustion the engine is operated with low lift and short duration valve timings where the variable negative valve overlap is used for combustion control. (Less)

Structural-acoustic Design of a Multi-functional Sandwich Panel in an Automotive Context

Abstract: This article deals with the design and weight optimization of a multi-functional vehicle body panel in an automotive context. An existing vehicle design has provided functional design requirements ...

Seaeye Sabertooth A Hybrid AUV/ROV offshore system

Abstract: Increasing use and complexity of subsea installations has put focus on the costs of maintaining these systems. In addition, access to these systems is sometimes limited by adverse weather and ice conditions. Conventional methods for intervention, maintenance and repair (IMR) using surface ships and ROVs are very expensive furthermore are response and mobilization times slow. To address this Saab Underwater Systems is in the process of developing a hovering Hybrid AUV/ROV system to remotely perform IMR without or strongly reduced need for a supporting ship. This system is based on the Double Eagle SAROV, a hovering Hybrid AUV/ROV in production for the military market and proven components from Saab Seaeye ROV product range.

Experience from introducing Unified Modeling Language-Systems Modeling Language at Saab Aerosystems

Abstract: A Unified Modeling Language-Systems Modeling Language (UML-SysML) subset was the modeling notation selected for an aerospace systems engineering project at Saab Aerosystems. In this paper, the rationale for selecting UML-SysML is given, along with a description of the situation at the project planning stage regarding business conditions, method and tools support. The usage of use case, sequence, and activity diagrams are described as well as definition of functional chains with SysML. Furthermore, the connections to system implementation activities including code generation and simulation are discussed. The advantages and disadvantages of using UML-SysML from experience in an industrial context are reported. It is also described how UML-SysML is related to industrial research projects in the Model Based Systems Engineering (MBSE) methods and tools area. Introducing UML-SysML with a methodology and a supporting toolset in an operative organization require a clear strategy, including planning, just-in-time training, and mentor support. Finally, industrial needs for further development of SysML are discussed. © 2009 Wiley Periodicals, Inc.

Assessment of visual cues by tower controllers, with implications for a Remote Tower Control Centre

Abstract: Remote control of airports implies application of cameras to replace direct visual observation from airport control towers by projection of the airport and its traffic in a remote control centre. Remote airport control is an emerging technique with benefits for smaller airports mainly, because it reduces the cost of personnel. Surprisingly, hardly any literature can be found to list the required visual objects and phenomena for tower control, i.e. the visual cues that need to be seen for tower control. The composition and validation of the so-called visual cue list for tower control is the subject of this paper. Tower controller task analysis was used to compose a ‘long-list’ of visual features. The long-list has been presented to a group of operational air traffic controllers to test the need and the circumstances to observe these visual cues. Our analysis shows that most of the visual cues are useful for operational tower control but are not strictly mandatory for applying the rules of the International Civil Aviation Organization.. The requirement for visual image resolution of remote tower control is the second subject of the paper. Our analysis leads to definition of a ‘short-list’ of important safety-related visual objects and phenomena for tower control and the conclusion that state of the art media are just able to provide the required image resolution for visual detection but not for recognition.

Combined vertical farm, biofuel, biomass, and electric power generation process and facility

Abstract: Methods and associated apparatus for automatically growing agricultural crops vertically and/or in a continuous fashion throughout each year (Vertical Farm) in combination with contiguous and co-located production of biofuel, food, biomass for the purpose of carbon sequestering (carbon credits), and biomass electric power generation. A process that incorporates vast arrays of continuous-loop conveyors, towering upon vertical framework, which allow potted perennial plants to be transported throughout all stages of maturity in a manner which substantially multiplies yield per acre, allows production to proceed in both natural and artificial light, allows production and harvesting to be automated, and allows production to proceed in conditions which are highly favorable to plants but unfavorable to humans. The entire apparatus can be constructed of lightweight, cost-effective materials which afford mass-production and mass- array into vast automatic growing operations.

Stall Development in a Ported Shroud Compressor using PIV Measurements and Large Eddy Simulation

Abstract: Surge is a phenomenon that limits the operational range of the compressor at low mass flow rates. The objective of this research is to study effective operational range for a ported shroud compressor. The size of the compressor is typical for a turbocharger used on diesel engines. To be able to extend the operational range, the surge characteristics have to be assessed. This is done by performing measurement of the flow at the inlet to the compressor wheel and pressure fluctuations at the inlet and outlet of the compressor housing. Detailed numerical computations of the flow in the entire compressor section under similar operating conditions have also been carried out. The experimental work includes Particle Imaging Velocimetry (PIV) measurements of the instantaneous and mean velocity field at the inlet. At surge, low frequency pulsations are detected that seem to result from back flow already observed in stall. The numerical computations include details of the flow by having good spatial and temporal resolution and using Large Eddy Simulations (LES) to account for the turbulence. LES is most suitable for the surge flow since it resolves the large scale structures, such as flow separation and reversed flow, which characterize surge.

Dynamic testing and simulation of hybrid joined bi-material beam

Abstract: A specimen is developed for real-like low velocity impact testing of bi-material joint configurations. Six different joint configurations are analysed. Two engineering adhesives are evaluated with and without discrete mechanical fasteners, i.e. adhesive and hybrid joints. Experiments and simulations are performed. The simulations are performed using adhesive cohesive finite elements. Simulations show good agreement with experiments in impact energy and overall deformation mode. The histories of applied load vs. load-point deflection show reasonably good correlation. The results show that the impact energy consumption depends on the joint integrity. A threshold value for the fracture energy of the adhesive seems to exist. Beneath this value, adhesive and discrete fastener work together increasing the impact energy capacity. Above this value the discrete fastener has a negative effect, and may be regarded as a stress concentration.

Categorization of real-time software components for code size estimation

Abstract: Background: To estimate Software Code Size early in the development process is important both for Cost/Effort estimation and electronic hardware design reasons. The COSMIC FSM (Functional Size Measurement) method treats the intended software to be measured as a black box, and measures CFP (COSMIC Function Points) based only on data movement in and out of the software. Therefore, CFP can be measured on requirements defined early, and be used to estimate Code Size if there exists a strong correlation between CFP and Code Size. We have conducted four experiments in the automotive industry showing strong correlation between CFP and implemented Code Size in Bytes. All four experiments, of which two have not been published before, show equally strong correlation but the linear relationship is different between the experiments.Goal: This paper aims to identify the factors affecting the linear relationship. With these factors, we can categorize new requirements to be measured and select the proper linear relationship to convert CFP into Bytes, i.e. estimate Code Size.Method: We replicate our earlier experiments with software components of new types, and review the results from all our experiments. Potential factors affecting implemented Code Size are identified by performing open-ended interviews with domain experts.Results: We have in the automotive industry identified a set of factors that can be used to categorize the software components we want to measure; functionality type, quality constraints, and development methods and tools.Conclusions: COSMIC can produce accurate Code Size Estimates provided that sub-sets of cohesive and uniform requirements can be identified. Moreover, similar requirements must have been measured before to establish the linear relationship between CFP and Bytes. Finally, the sub-sets of requirements need to be able to categorize based on factors that affect the linear relationship. With this approach, even complex calculations can be measured, provided that they are proportional to the number of data movements.

On the relationship between functional size and software code size

Abstract: SLOC (Source Lines-Of-Code) has been used extensively as a Code Size Measure, and as input to parametric software cost and effort estimation tools. SLOC is obtained by measuring FP (Function Points) on the requirements and multiplying by the SLOC/FP ratio from similar projects. This is done even though several studies show large variations in this ratio, due to weak correlation between FP and SLOC. However, in our previous experiments we have obtained strong correlation between CFP (COSMIC Function Points) and Bytes compiled code as Code Size Measure. The experiments were conducted in the automotive industry using software components developed by GM (General Motors). In this paper we explain the reasons behind the strong correlation. The main reasons are that we apply the COSMIC method on software components of similar type, with a 1-to-1 mapping to COSMIC. A strong correlation between the Functional Size Measure and the Code Size Measure is required to obtain accurate Code Size estimation results. To estimate the Code Size before the software is available, is important both for Cost/Effort estimation and design of electronic hardware.

Physical bounds on the all-spectrum transmission through periodic arrays: oblique incidence

Abstract: The performance of a low-pass screen designed to block electromagnetic waves in a stop band is shown to have an upper bound defined by the static electric and magnetic polarizability per unit area of the screen. The bound is easy to calculate for all angles of incidence and polarizations, and applies regardless of how complicated the screen's microstructure is. For a homogeneous dielectric sheet the bound for TM polarization is more restrictive than the bound for TE, but this is not generally true for a screen with microstructure. The results are verified by measurements and simulations of oblique transmission through an array of split ring resonators, printed on a dielectric substrate.

Effortless Data Capture for Ambient E-Services with Digital Pen and Paper Technology

Abstract: In order to counteract the digital divide and to enable the society to reach all its citizens with various kinds of e-services, there is a need to develop access methods and terminal technologies suited also for groups with weak access to the Internet, not the least elderly and people needing care in their homes. In this chapter, the authors will describe technologies for using digital pen and paper as data input media for e-services and computing applications, refer a number of applications together with studies and evaluations of their usability, and finally comment upon future prospects for integrating digital pen and paper as an effortless technique for data capture, especially in order to counteract and diminish the digital divide. The use of digital pen and paper technologies is exemplified with applications demonstrating its appropriateness in home care for elderly, for free-form recording of data on paper such as maps, and as a remote control for a TV set or other electronic appliances with rich functionality in the home.

Agile architecture framework for model driven development of C 2 systems

Abstract: Command and Control (C2) systems are complex systems composed of personnel, technical equipment, organizational structures, and work procedures. This complexity increases the difficulties involved in developing such systems, which in turn leads to a need for supportive development measures. This paper presents and explores an agile, lightweight, architecture framework for the development of C2 systems. The architecture framework prescribes a model-driven process for structuring the developed models into various levels and views. This facilitates the developers' ability to consider the C2 system from a holistic and concurrent perspective. By applying the architecture framework, both the C2 system and its context are modeled in order to study how the C2 system should be used to support the performance of operational activities, and what support the technical system should provide to the commanders, who are a part of the C2 system. The architecture framework provides traceability from the operational level to the technical systems via the C2 systems. The architecture framework was iteratively developed and evaluated in three sequential case studies. The outcome shows that the framework supports the initial steps in the development of complex systems, such as C2 systems. However, further development and evaluations of the architecture framework are necessary. © 2009 Wiley Periodicals, Inc. Syst Eng

Advanced remote tower project validation results

Abstract: The Advanced Remote Tower project (ART) studies enhancements to an existing LFV prototype facility for a remotely operated tower: projection on a 360 degrees panorama screen, adding synthesized geographic information and meteorological information, video tracking, fusion of video and radar tracks, labelling, visibility enhancement and surveillance operations with a remotely controlled Pan Tilt Zoom camera. The ART functions have been embedded in the existing Swedish test facility for remote tower operations in Malmo airport Sturup observing Angelholm traffic about 100 km to the North. They were tuned and validated by 15 tower controllers. Emphasis was on the traffic and situation awareness of tower controllers using remote cameras and projection system for safe operational tower control, replacing direct view on the airport and its traffic. The validation results give valuable information for further development and operational application even outside the Remote Tower application area.

CFD assisted design evaluation and experimental verification of a logic controlled local PCB heater for humidity management in electronics enclosure

Abstract: Humidity management of commercial-of-the-shelf electronic components in non-controlled climatic environments can be realized e.g. by introducing a local printed circuit board heater. By choosing appropriate size and location of the heater plate in the vicinity of the critical electronic packages, and utilizing logic control function, it is possible to improve the quality of local humidity management and reduce power consumption of the heater, which is important especially in case of battery driven portable or vehicle mounted devices. A computational fluid dynamics assisted methodology has been developed to determine the best feasible design of the heater, followed by experimental verification of the constructed logic controlled heater. The experiment has been performed in a harsh climatic environment including temperature variation from +33 °C to +40 °C, and relative humidity variation from 54% to 80%. Analysis of the experimental %RH and temperature curves as well as power profile of the heater has confirmed the feasibility of the chosen approach to maintain greater than 9°C difference between the electronics package surface temperature and the local dew point temperature, by applying discrete power pulses with the amplitude less than 6 W.

Navigation in vehicle crash test using MEMS-based IMU

Abstract: Results from our experiments on inertial navigation in crash testing of vehicles are presented. A custom designed inertial measurement unit (IMU) has been developed, and several tests in dummy calibration rigs including full-scale Euro NCAP collisions have been performed at our partners' crash test laboratories. For reference, the IMU data is compared to camera data and traditional single-axis inertial sensors.

4.5.3 Experience from Introducing SysML into a Large Project Organisation

Abstract: Introducing a model centric way of working in large organisations is difficult. At SAAB Aerosystems it has been tried over multiple years in many projects. Success has been limited. In our latest attempt to introducing SysML as a tool for system design it was decided to change focus. Instead of trying to promote models as the new way of documentation it was decided to setup the tools with the objective to create consistent and readable document centric deliverables. Instead of giving the modellers the freedom to use the language at its extreme, it was decided to limit language use to an absolute minimum. As a result there have been some quite drastic initial complaints from our some experienced modellers, but surprisingly strong acceptance of the new approach to modelling from the stakeholders responsible for quality control, but not directly involved in the core development team.

Realization of an active inductance for a low power high bandwidth DC power line communication network transceiver

Abstract: An active inductor based on an improved gyrator circuit is proposed. The active inductor is developed to be implemented in a high impedance transceiver for a wearable DC power line communication network where requirements such as low power consumption, high bandwidth and numerous nodes support are prioritized. A load isolation step is introduced to ensure the stability of the active inductance's size on different load currents. The proposed gyrator circuit is analyzed and optimized by means of theoretical calculations. The theoretical results are then verified by simulations and experiments in the frequency range up to 10 MHz.

A vehicle powertrain arrangement

Abstract: The present invention relates to a vehicle powertrain arrangement, comprising a first vehicle propelling machine (101) having a first input shaft (112) and a second vehicle propelling machine (102) having a second input shaft (116), both of said vehicle propelling machines (101, 102) being coupled to a first output shaft (114). Said first vehicle propelling machine (101) is coupled to said first output shaft (114) via a first input gear set (180) and said second vehicle propelling machine (102) is coupled to said first output shaft (114) via a second input gear set (188), and said first (112) and second (116) input shafts are located in parallel with and each one at a respective distance from said first output shaft (114).

Transmission control arrangement, transmission, vehicle and method for transmission control

Abstract: There is provided an automatic or semiautomatic transmission for a motorized vehicle, comprising a guide (106;206) which is arranged to receive and control the position of at least two guided members (110,120;220,230), wherein the position of a guided member controls the mode of operation of a predetermined actuation device (260,250;260,350) e.g. gear selector, clutch plate or park brake etc. By moving said guide relative said guided members, the guided members are synchronously arranged at sequential pairs of positions (P1-P8), wherein said pairs of positions correspond to predetermined combinations of modes of operations of said actuation devices. In this way a synchronized and sequential series of movements of at least two actuation devices is provided, which may synchronize the movement of e.g. a gear selector and a clutch such that a change from a first gear via a neutral gear to a second gear is provided.

Predictions of the Performance of a Radial Turbine with Different Modeling Approaches: Comparison of the Results from 1-D and 3-D CFD

Abstract: In this paper, the performance of a radial turbine working under pulsatile flow conditions is computed with two different modeling approaches, time resolved 1-dimensional (1-D) and 3-dimensional (3-D) CFD. The 1-D modeling approach is based on measured turbine maps which are used to compute the mass flow rate and work output from the turbine for a given expansion ratio and temperature at the inlet. The map is measured under non-pulsatile flow conditions, and in the 1-D method the turbine is treated as being a quasi-stationary flow device. In the 3-D CFD approach, a Large Eddy Simulation (LES) turbulence approach is used. The objective of LES is to explicitly compute the large scales of the turbulence while modeling the effects of the unresolved scales. Three different cases are considered, where the simplest case only consist of the turbine and the most complex case consist of an exhaust manifold and the turbine. Both time resolved data, such as pressure ratio, temperature and shaft torque and time mean data from the two different modeling approaches are compared. The results show that the computed time mean shaft power differs between the two different modeling approaches with as much as 100%. Since the considered operation point for the engine in this study is 1500 rpm with wide open throttle, the turbine operates in an area where the turbine map is extrapolated. Only by using a few operation points from CFD to extend the map, an improvement is achieved for the 1-D results, but still the deviation is large. Also, the pressure ratio and temperature drop over the turbine differs for the used modeling approaches. The causes for the deviations are assessed and discussed to get a better understanding of eventually limitations of the 1-D modeling approach.

Evaluation of tyre to road friction estimators, test methods and metrics

Abstract: The tyre to road contact friction is one of the most important properties when it comes to manoeuvrability of ground vehicles and information, to driver and vehicle, is of vital importance in critical situations. Different characteristics of different friction estimation methods make it hard to determine and compare performance of estimators. This article is an attempt to define and evaluate the performance of tyre to road friction estimators. The objective of the performance evaluation is to define and grade the performance of estimators based on all sorts of approaches and combinations of these. The result may be used in the context of benchmarking as well as a tool in the development process of the estimator. The test methods and metrics presented are illustrated with a comparative study of three different estimation approaches.

Medical device with adjustable tissue ingrowth cuff

Abstract: Methods and apparatus are disclosed for making and using adjustable epidermal tissue ingrowth cuff and catheter assemblies for transcutaneous placement to provide periodic or continuous external access for medical purposes to an interior body region of a patent who requires such medical treatment over an extended period of time.

Optimal repair for repairable components during phaseout an aircraft fleet

Abstract: The successive removal of units from a group of systems during phasing out leads to a variable requirement for stock level of spare parts. Repairable units from phased out systems can be reused for the remaining functional systems in the group. Hence, the stock level of spare parts increases and the demand for spare parts decreases. This can lead to excessive stocking of spare parts and high maintenance costs for spare parts. This paper proposes a methodology to determine the optimum time to stop repair of repairable units to minimize the maintenance cost. It uses a Poisson Distribution based on NHPP (Non-Homogenous Poisson Process) to predict the available number of units, while fulfilling the demand for spare parts for the remaining systems. A concept, called Minimal Margin is introduced to formulate the problem and nonlinear programming is proposed to obtain the optimum solution. Finally, a numerical example is presented to demonstrate the approach.