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The solid state power controller (SSPC) is one of the most important power electronic components of the aircraft electrical power distribution (EPS) systems. This paper presents an architecture of the DC SSPC and provides the mitigation techniques for transient voltage overshoot during its turn-off. The high source side inductance carries breaking current (9xnominal current) just before turnoff and induces large voltage transient across the semiconductor devices. Therefore, the stored inductive energy needs to be dissipated in order to prevent semiconductor switches from over-voltage/thermal breakdown. Three different transient voltage suppression (TVS) devices to reduce voltage stress across switches are included in the paper for detail study. The comprehensive comparison of the TVS devices is presented. In addition, the thermal impact of the TVS devices on the semiconductor switches is also analyzed.

The paper will deal with the problem of establishing a desirable power sharing in multi-feed electric power system for future more-electric aircraft (MEA) platforms. The MEA is one of the major trends in modern aerospace engineering aiming for reduction of the overall aircraft weight, operation cost and environmental impact. Electrical systems are employed to replace existing hydraulic, pneumatic and mechanical loads. Hence the onboard installed electrical power increases significantly and this results in challenges in the design of electrical power systems (EPS). One of the key paradigms for future MEA EPS architectures assumes high-voltage dc distribution with multiple sources, possibly of different physical nature, feeding the same bus(es). In our study we investigate control approaches to guarantee that the total electric load is shared between the sources in a desirable manner. A novel communication channel based secondary control method is proposed in this paper.

The assembly and manufacture of aerospace structures, in particular legacy products, relies in many cases on the skill, or rather the craftsmanship, of a human operator. Compounded by low volume rates, the implementation of a fully automated production facility may not be cost effective. A more efficient solution may be a mixture of both manual and automated operations but herein lies an issue of human error when stepping through the build from a manual operation to an automated one. Hence the requirement for an advanced automated assembly system to contain functionality for inline structural quality checking. Machine vision, used most extensively in manufacturing, is an obvious choice, but existing solutions tend to be application specific with a closed software development architecture.

In this paper, the load sharing principles in dc-distribution electric power systems (EPS) for future more-electric aircraft (MEA) are investigated. The study is conducted using a potential MEA EPS architecture with multiple sources feeding into the main dc bus. Corresponding reduced-order EPS models are established. The influence of the cable impedance on the load sharing accuracy is analyzed and sharing error is quantized in mathematical equations. In addition, source/load impedance of the droop-controlled system has been derived leading to the discussion of the stability issues in multi-feed dc EPS under different droop control strategies. The influence of load sharing ratio on the EPS stability margins has been investigated. The theoretical findings were supported by time-domain simulations in Matlab/SimPower.

This paper presents an innovative solution of portable drilling machine, lightweight and low cost, dedicated to drilling operations on single and double curved aircraft structure. Aircraft Standard drilling process mainly uses drilling templates combined with Automated Drilling Units (ADU) which is a very efficient solution. However, the management of templates and ADUs is a time consuming and costly task in regards to the large quantity of existing references spread over every aircraft production sites. Therefore, to help reducing those costs and also workload, the concept of the Numerical Template (NCT) has been designed, using classic and robust mechanical devices, hand-held, lightweight and universal. NCT architecture concept could led to a family of NCT with different dimensions of frame parts(X,Y,Z), fitted to the targeted area geometry. The system is able to guaranty an accuracy of ± 0.5 mm and a normality of ±0.5°.

Many More-Electric Aircraft (MEA) Electric Power System (EPS) architecture paradigms are being studied in order to provide the on-board electrical loads with high-quality supply and to ensure safe operation. EPS with dc distribution appears to be more promising due to higher efficiency, higher reliability, easier integration and lower overall weight. Another advantage of dc systems is the ease of sources paralleling, together with the optimization of load power sharing, this can lead to further EPS weight reduction. The DC bus can be fed by multiple sources such as generators, batteries and other energy storage devices. Many loads in MEA EPS are tightly controlled by power electronic converters and often behave as constant power loads (CPL). These are known as main contributors to the degradation of EPS stability margins. Therefore, stability study is one of the key topics in the assessment of potential EPS architecture candidates.

As future commercial aircraft incorporates more EMAs, the aircraft electrical power system architecture will become a complex electrical distribution system with increased numbers of power electronic converters (PEC) and electrical loads. The overall system performance and the power management for on-board electrical loads are therefore key issues that need to be addressed. In order to understand these issues and identify high pay-off technologies that would enable a major improvement of the overall system performance, it is necessary to study the aircraft EPS at the system level. Due to the switching behaviour of power electronic devices, it is very time-consuming and even impractical to simulate a large-scale EPS with some non-linear and time-varying models. The dynamic phasor (DP) technique is one way to solve that problem.

In recent years, a number of key influences are contributing to accelerate technological innovation in the automotive industrial sector. Concerns about renewable energy resource, fossil-fuels crises and higher gasoline prices, global warming awareness and environmental impacts, scarcity of minerals/metals and electronics demands rising are some of the major challenges for vehicle automakers and their suppliers. The interest in alternative fuel vehicles, especially hybrid-electrical vehicles (HEV) or renewable energy power concepts for road vehicles has become intensified and represents a significant area of research and development in order to meet nowadays global demands. However because of Hybrid Vehicles unique Power Supply System the electrical/electronic architecture (E/E) is sophisticated, requesting more robust sealing and a particular wiring harness components, such as connector, terminals and cables.

The complexity of automotive software and the needs for shorter development time and software portability require the development of new approaches and standards for software architectures. The AUTOSAR project is one of the most comprehensive and promising solutions for defining a methodology supporting a function-driven development process. Furthermore, it manifests itself as a standard for expressing compatible software interfaces at the Application Layer. This paper discusses the implementation of AUTOSAR requirements for the component structure, as well as interfaces to the Application Layer in a model-based development environment. The paper outlines the major AUTOSAR requirements for software components, provides examples of their implementation in a Simulink/Stateflow model, and describes the modelbased implementation of an operating system for running AUTOSAR software executables (“runnables”).

In recent years, the desire for improved vehicle performance, reliability and safety have increased the electrical content and its complexity in vehicles. Advanced automotive systems integrate sensors, controllers, actuators and communication networks. To maintain safety and reliability, a comprehensive system of diagnostics and physical and analytic redundancy are used. In some cases, diagnostic strategies based on analytical redundancy can provide detection, as well as fault-tolerance, and may provide benefits in cost, packaging, flexibility and reusability. This paper discusses a range of diagnostic methods and their applicability to advanced automotive systems such as X-by-Wire. It will also show the reduction to practice of an advanced analytical technique for an automotive application.

The increasing features and complexity of today's automotive architectures are becoming increasingly difficult to manage. Each new innovation typically requires additional mechanical actuators and associated electrical controllers. The sheer number of black boxes and wiring are being limited not by features or cost but by the inability to physically assemble them into a vehicle. A new architecture is required which will support the ability to add new features but also enable the Vehicle Assembly Plants to easily assemble and test each subsystem. One such architecture is a distributed multiplex arrangement that reduces the number of wires while enabling flexibility and expandability. Previous versions have had to deal with issues such as noise immunity at high switching currents. The LIN Bus with its low cost and rail-to-rail capability may be the key enabling technology to make the multiplexed architecture a reality.

Automotive occupant safety continues to evolve. At present this area has gathered a strong consumer interest which the vehicle manufacturers are tapping into with the introduction of many new safety technologies. Initially, individual passive devices and features such as seatbelts, knee- bolsters, structural crush zones, airbags etc., were developed for to help save lives and minimize injuries in accidents. Over the years, preventive measures such as improving visibility, headlights, windshield wipers, tire traction etc., were deployed to help reduce the probability of getting into an accident. With tremendous new research and improvements in electronics, we are at the stage of helping to actively avoid accidents in certain situations as well as providing increased protection to vehicle occupants and pedestrians.

The interdependence of consumer features, new electronic and electrical architectures and hybrid propulsion systems are examined. There are two major forces driving future vehicle electronic and electrical systems, one is consumer demand for comfort and safety, and two is the demand for reduced fuel consumption and emissions. These forces are linked by the use of electronics to control vehicle energy generation and usage while providing managed solutions to these demands. Automobile consumer features are discussed and the case is made that these features will require more electric power to be installed on the vehicle. The presence of this increased electric power will then enable the hybrid vehicle functions that will benefit fuel economy and emissions performance.

The electric power required in automotive systems is quickly reaching a level that significantly impacts costs and fuel consumption. This drives the need to reconsider an electric energy management function. Fast evolving factors such as increasing power usage, and stricter engine management and reliability requirements necessitate a global vehicle approach to energy management. Innovations such as new powernet concepts (42 volt or dual voltage systems), new component technologies (high-performance energy storage, high efficiency and controllable generators), and global electronic and software architecture concepts will enable this new energy management concept. This paper describes key issues to maximize energy availability with reasonable components.

The automotive industry is moving to a higher voltage for the electrical system. This change will occur because the total electrical power required by the vehicles will increase to a level where the current requirements at 14 volts will be impractical. Some of the new loads will change the duty cycle of the battery. The most notable change is the proposed start/stop mode of vehicle operation where the engine is stopped and restarted frequently to avoid prolonged operation at idle. An additional feature would be to use an electric motor to assist in acceleration and/or to actually launch the vehicle. This paper addresses the changes in battery requirements brought on by these new features. A means of analysis for choosing the appropriate battery technology is presented. We also propose a life test to establish a benchmark for current battery technology when it is used in a new duty cycle.

The industry strategy for automotive safety systems has been evolving over the last 20 years. Initially, individual passive devices and features such as seatbelts, airbags, knee bolsters, crush zones, etc. were developed for saving lives and minimizing injuries when an accident occurs. Later, preventive measures such as improving visibility, headlights, windshield wipers, tire traction, etc. were deployed to reduce the probability of getting into an accident. Now we are at the stage of actively avoiding accidents as well as providing maximum protection to the vehicle occupants and even pedestrians. Systems that are on the threshold of being deployed or under intense development include collision detection / warning / intervention systems, lane departure warning, drowsy driver detection, and advanced safety interiors.

Adaptive Cruise Control (ACC) technology is presently on the horizon as a convenience function intended to reduce driver workload. This paper presents an implementation of a brake algorithm, which extends the production cruise control feature. A brief overview of the system architecture and subsystem interfaces to the forward-obstacle detection system, throttle and engine management controls are described. Considerations of moding ACC with ABS and Traction Control are presented at the vehicle level. This development activity is presented in two major phases. Both phases of this development project utilize CAN controllers and transceivers to implement requirements for limited access highway driving. The initial phase of development requires the brake control to follow a deceleration command and operate “open-loop” to the vehicle controller. Vehicle test data capturing smooth stops on high coefficient surfaces is presented as insight to the braking performance of the vehicle.

When comparing vehicle communication architectures, the passive star network has been shown to be the highest fault tolerant system. Despite this trait, the passive star architecture has not been widely implemented due to its potential application limitations: insufficient node count and relatively short node lengths. These constraints arise from the basic function of the star, i.e. to evenly distribute a given amount of optical power to all nodes connected to the star without amplification or retransmission. This paper provides a solution to overcome the limitations of the passive star through the introduction of a new communication component, the Active Distribution Node (ADN). The ADN enables a passive star network to support larger node counts and significantly longer node lengths, without sacrificing fault tolerance or the low cost nature of the basic passive star architecture.

Intense competition in the automotive industry requires continuous reduction in innovation cycle time, even as corporations are downsizing and system complexity is increasing. Subsequently, the application of recently introduced Rapid Algorithm Development (RAD) tools has facilitated significant advances in the development of embedded control systems. The RAD steps include system modeling, control algorithm design, simulation analysis, automated calibration design, and vehicle implementation through automatic code generation. The application of RAD tools and the associated benefits are described, specifically in the context of Engine Management Systems (EMS). Such benefits include significant reductions in development cycle time, open architecture, automated calibration, and information reuse.