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Technical Paper

Intelligent Fault Tolerant Systems for Thermal Control in Space Applications

This paper describes two smart fault tolerant systems (EURECA TCU and Pump Package ECU) that have been studied by MICROTECNICA in the frame of European Space programs. EURECA TCU: The TCU is the electronic unit of the FURECA Thermal Control System and consists of two cold redundant sections each with the prime task of controlling the temperature of 129 points on the carrier. It does this by switching on and off the appropriate heater, according to the temperature measured by the dedicated thermistors. Each control loop (thermistor, TCU, heater) is dual redundant and con be in case of one failure. The system can tolerate one failure without the loss of the correspondent control function. PUMP PACKAGE ECU: This is a proposed system to act as the electronic unit for the control and regulation of the mass Flow of a water and/or freon pump package. It consists of two redundant electronic control channels.
Technical Paper

Vapor Cycle System for a Fighter Aircraft - The Lantirn ECU Lessons Learned

The process of designing a Vapor Cycle System (VCS) for a fighter aircraft is a difficult and continuous challenge. Besides the constant efforts to optimize size, weight and package is the need to provide a highly reliable, producible and easily maintained system. In particular is the need to make the vapor compression system highly hermetic and intensely rugged. This paper updates the 1982 SAE paper entitled “Environmental Control of an Aircraft Pod Mounted Electronics System” (820869). Specifically it details the design, production and field results of the LANTIRN Environmental Control Unit (ECU). Since 1986 over 1000 of these systems have been fielded. The ECU has proven to be reliable in spite of the difficult environment, which has included combat duty. This paper will give insight into the LANTIRN pod thermal management system, the design of the ECU subsystem, and packaging.
Technical Paper

High-Efficiency Controlled Water Pump Assembly

The developed assembly is a Water Controlled Pump Assembly (WCPA) consisting of a hydraulic pump with its mechanical (bearings, seals) and hydraulic fittings. This pump is driven with a brush-less DC motor and its Electronic Control Unit. The manufactured pump package has been made according to ESA specifications. The optimal combination of hydraulic and electro-mechanic is the key of the high overall efficiency: more than 30%.
Technical Paper

Hybrid Drivetrain Simulation for Hardware-in-the-Loop Applications

This paper describes challenges and possible solution of hybrid electrical vehicles test systems with a special focus on hardware-in-the-loop (HIL) test bench. The degree of novelty of this work can be seen in the fact that development and test of ECU for hybrid electrical powertrains can move more and more from mechanical test benches with real automotive components to HIL test systems. The challenging task in terms of electrical interface between an electric motor ECU and an HIL system and necessary real-time capable simulation models for electric machines have been investigated and partly solved. Even cell balancing strategies performed by battery management systems (BMU) can be developed and tested using HIL technology with battery simulation models and a precise cell voltage simulation on electrical level.
Journal Article

Modeling of the Soot Accumulation in DPF Under Typical Vehicle Operating Conditions

The pressure losses across the different parts of a regenerative Diesel Particulate Filter (DPF) have been modeled and compared with the measured pressure loss and with the measured changes in the instantaneous weight of the DPF of a commercial automotive diesel engine. The comparisons were made in three operating conditions selected among those included in the transient cycle established in the European Emission Directive. The first one is a low-load mode, with high soot emissions and therefore with high contribution to the DPF charge. The second one is a medium-load mode, in which the balance of soot charge versus spontaneous soot regeneration leads to a slow DPF charging, the temperature at the exhaust manifold being high enough to permit active regeneration. The third one is a high-load mode, in which the spontaneous regeneration leads to a net DPF discharge, the active regeneration becoming useless.
Technical Paper

AUTOSAR Gets on the Road - More and More

AUTOSAR (AUTomotive Open System ARchitecture) is a worldwide standard for automotive basic software in line with an architecture that eases exchange and transfer of application software components between platforms or companies. AUTOSAR provides the standardized architecture together with the specifications of the basics software along with the methodology for developing embedded control units for automotive applications. AUTOSAR matured over the last several years through intensive development, implementation and maintenance. Two main releases (R3.2 and R4.0) represent its current degree of maturity. AUTOSAR is driven by so called core partners: leading car manufacturers (BMW, Daimler, Ford, GM, PSA, Toyota, Volkswagen) together with the tier 1 suppliers Continental and Bosch. AUTOSAR in total has more than 150 companies (OEM, Tier X suppliers, SW and tool suppliers, and silicon suppliers) as members from all over the world.
Technical Paper

Windows Based Software Development Platform for AUTOSAR ECUs

As the amount of embedded software in the vehicle increases dramatically, the software design and development tasks are daunting. Over the past few years, the automotive industry has taken measures to increase software re-use and promote competition among basic software vendors. If AUTOSAR has emerged as the de-facto standard for embedded automotive software development, there are numerous challenges ahead as the standard assumes the availability of both the hardware and the associated abstraction layer among others. This can be problematic for developers. Furthermore, engineers may be interested in performing early what if tests - early functional tests - to ensure that their strategies will not cause problems later in the development process. As always, errors are less costly to fix if they can be caught early. With AUTOSAR several thousand parameters have to be configured in about 60 modules.
Technical Paper

Automotive Electric System Level Design Methodologies with SystemC

ESL (Electric System Level) Design Methodologies enable us to design and verify various electrical behaviors of automotive electronics including automotive semiconductors on a simulator before hardware prototyping. It could facilitate the optimization of hardware structures, and shorten the total development period by reducing rework process. We propose the “ESL Design Methodologies for Automotive” to renovate conventional development scheme. ESL technology began to be used from the domain of digital consumer electronics. Regarding automotive electronics domain, however, we would not be able to adapt the same methodologies to automotive systems, which consist of many mixed-signal components. Also, another approach is required for the rising demand of safety design sort of functional safety.
Technical Paper

Software Function Allocation and Configuration of an AUTOSAR-Compliant System

The software part of an automotive embedded system continues to increase significantly. It enables the development of new functionalities and it may improve the quality and comfort of driver assistance functions. However, the design of such functions becomes a complex task involving networked ECUs (Electronic Control Unit), several sensors/actuators and a set of embedded networks. The introduction of Model-Based Development (MBD) in the automotive field promised to improve the development process by allowing continuity between requirements definition, system design and the distributed system implementation. Further, the definition of AUTOSAR consortium standardized the design of such automotive embedded system by allowing the portability of software functions on the hardware architecture and their reuse. It defines a set of rules and interfaces to design, interconnect, deploy and configure a set of application software components (SWCs).
Technical Paper

Selection of a Brushless DC Motor Employed to Propel an Electric Car

This work presents the results of the development of a small electric car and the study of a Brushless DC Motor, employed to propel the electric car. The aim was selecting a motor with characteristics of operation suited to propel the electric car at a speed from 12 to 20 km/h. The propulsion system has a brushless DC motor and an electronic control unit. The electronic control unit was designed and constructed based on the characteristics of the selected brushless motor. Tests were carried out on the electric car, with the purpose of determining the behavior of the mechanical power required by it, as a function of speed. The results allowed selecting a brushless motor with the following characteristics: 12 V, 5.9 A and 13600 rpm. A theoretical study was developed to determine the suited gear ratio between the speed of the motor and the speed of the wheels of the car.
Technical Paper

A Discussion on the Use of an Integrated Modular Avionics (IMA) Architecture to Simulate an Aerospace Control System

The use of control architectures with the Integrated Modular Avionics (IMA) concept (“IMA architectures”) in aerospace and the Integrated Modular Electronics (IME) concept (“IME architectures”) in automotive applications is growing due to its reduced number of hardware such as processors, Line Replaceable Units (LRUs) and Electronic Control Units (ECUs), thereby reducing weight and costs. Furthermore, IMA architectures can perform complex reconfigurations in the case of failures and adapt themselves to changes in network functioning or operating modes, which make a control system very robust. The objective of this work is to discuss the use of an IMA architecture to simulate an aerospace control system responsible for maintaining a vehicle in a predetermined trajectory. To do that, we review the current literature related to IMA architectures and give an overview of their characteristics. Then, we choose an aerospace control system and discuss its simulation using an IMA platform.
Journal Article

Research on Measurement Method of Road Gradient and Altitude by On-Road Driving

Exhaust emissions from a vehicle under road driving condition is affected by the control state of ECU (Engine Control Unit). This control state highly depends on the driving force of the vehicle. The driving force is nearly equal to the driving resistance, which is the sum of the acceleration resistance, the air resistance, the rolling resistance and the gradient resistance. Although it is essential to take an accurate measurement of the road gradient, it is quite difficult to evaluate the gradient resistance in testing on-road driving. In this study, the measurement methods of the road gradient and the altitude with GPS, gyro sensor and height sensor are reported. The road gradient under the on-road driving condition is evaluated by the combination of measuring the pitch angle with the gyro sensor and measuring the vehicle gradient with the two height sensors. Verifying of this method, the altitude of the driving test route is also evaluated.
Technical Paper

The Tri-Core Fault-Tolerant Control for Electronic Control Unit of Steer-By-Wire System

In order to solve the reliability and security problems which are caused by the structural alteration of the traditional steering system, the fault-tolerant control method for the Electronic Control Unit of Steer-By-Wire system is studied in this paper. A hardware structure of SBW, with triple cores and dual motors is present. And one triple-loop control system and a triple-core control mechanism which is coordinated by distributed processing mechanism and voting mechanism are proposed too. The communication among steering feeling motor, steering motor and cores is achieved through FlexRay bus. The Hardware-in-loop Simulations test result shows that the reliability and safely of the Electronic Control Unit of Steer-By-Wire system is effectively improved.
Technical Paper

Simulation and Test Systems for Validation of Electric Drive and Battery Management Systems

Currently, hybrid and electric drive control systems are being developed for many types of platforms in the aerospace, automotive, and commercial vehicle industries. These systems also entail the use of Battery Management Systems (BMS) to handle their demanding power needs. However, the development of these technologies brings increased system complexity, evident in the platform variants and even more so in the control algorithms of various electronic control units (ECUs). There is also a greater need to handle system-level control strategies, via communication networks and command software. This increased system complexity poses new challenges for software design and ECU system validation, mandating the need for simulation tools that can easily handle the inherent system complexity, while providing cost-effective, industry-proven verification tools and processes.
Technical Paper

Robustness Modelling of Complex Systems - Application to the Initialisation of a Hybrid Electric Vehicle Propulsion System

Robustness is particularly important in complex systems of systems due to emergent behaviour. This paper presents two novel, techniques developed as part of a framework for design for robustness of complex automotive electronic systems, but in principle could be applied to a broad range of distributed electronic systems. The overall framework is described to give the context of use for the techniques. The first technique is a “robustness case” which is a structured argument for the robustness of a system analogous to a safety case. The second is a model based approach to early robustness verification of complex systems. The approaches are demonstrated by their application to the system initialisation of the propulsion control system of a hybrid electric vehicle. The hybrid system initialisation process is discussed in terms of the key objectives and the technical implementation, illustrating the level of complexity underlying a simple high level requirement.
Technical Paper

Manufacturing Support Design for Low-Cost Instrument Clusters

All automotive ECUs are required to be designed for manufacturability. Sufficient support in the ECU product design needs to be incorporated early in the product life cycle for the product to be successfully and efficiently manufactured, necessitating serial communication capability in the design. However, in low-cost automotive Instrument Clusters the customer requirements for the product typically do not encapsulate serial communication, and the ECU is not required to support repair/rework out of field rejection. This paper delineates the said need, examines the challenges for manufacturability of low-cost Instrument Clusters and proposes a plausible design strategy to help the issue with a use-case instance.
Technical Paper

Fundamental Investigations on the Boost Pressure Control System of Charged Aircraft Engines in the Aviation Class ELA1 / Approved Systems Versus New Solutions

Aircraft engines in the (ELA1) category, with a maximum power of up to 100kW, are characterized by a verified state of the art technology. New developments of engine technologies and control methods are very slowly being introduced into this engine segment. This trend is based on the fact that new technologies implemented in aircraft engines must be thoroughly certified and validated in a very complex and documented procedure. For this reason, most of the engines in this class are equipped with a carburetor as an air/fuel mixture preparation system. Moreover, naturally aspirated spark ignited engines are widely used in the aircraft category, with a take-off weight of up to 1000kg.
Technical Paper

From Virtual Testing to HIL Testing - Towards Seamless Testing

To make the development of complex aircraft systems manageable and economical, tests must be performed as early as possible in the development process. The test goals are already set in advance before the first hardware for the ECUs exists, to be able to make statements about the system functions or possible malfunctions. This paper describes the requirements on and solutions for test systems for ECUs that arise from these goals. It especially focuses on how a seamless workflow and consistent use of test systems and necessary software tools can be achieved, from the virtual test of ECUs, which exist only as models, up to the test of real hardware. This will be shown in connection with a scalable, fully software-configurable hardware-in-the-loop (HIL) technology. The paper also covers the seamless use of software tools that are required for HIL testing throughout the different test phases, enabling the reuse of work products throughout the test phases.
Technical Paper

Flexible Avionics Testing - From Virtual ECU Testing to HIL Testing

Hardware-in-the-loop (HIL) testing is an indispensable tool in the software development process for electronic control units (ECUs) and Logical Replaceable Units (LRUs) and is an integral part of the software validation process for many organizations. HIL simulation is regarded as the tried-and-tested method for function, component, integration and network tests for the entire system. Using the Model based design approach has further enabled improved and faster HIL implementations in recent years. This paper describes the changing requirements for HIL simulation, and how they need to be addressed by HIL technology. It also addresses the challenges faced while setting up a successful HIL system: namely the division of tasks, the total cost of ownership, budget constraints and tough competition and the adaptability of a HIL simulator to new demands. These requirements are discussed using a dSPACE HIL system architecture that was designed from the ground-up to address these needs.
Technical Paper

Diagnostic Method for a Landing Gear and Doors Actuation System Based on a State Machine Control Algorithm

A Landing Gear Control and Actuation System (LGCAS) is one of the most complex aircraft systems. Due to the large landing gear masses and high performance requirements, aircraft hydraulic power with multiple hydraulic actuators and valves is used to provide system dynamic. LGCAS also requires a electrical source of energy for the electro-mechanical components, sensors and electronic control unit. For many years, correct fault isolation in a complex kinematic system, such as an aircraft landing gear actuation system, has been a great challenge with limited success. The fault isolation design challenge rests on the fact that landing gear control and actuation system has many so called “passive” components, whose basic function cannot be continuously monitored without additional sensors, transducers, and designated health monitoring equipment.