Joseph G. D'Ambrosio

Configuration-level hardware/software partitioning for real-time embedded systems

We present an approach to hardware/software partitioning for real-time embedded systems. The abstraction level we have adopted is referred to as the configuration level, where hardware is modeled as resources with no detailed functionality and software is modeled as tasks utilizing the resources. Through configuration-level analysis, cost and performance tradeoffs can be studied early in the design process and a large design space can be explored. Feasibility factor is introduced to measure the possibility of a real-time system being feasible, and is used as both a constraint and an attribute during the optimization process. Optimal partitioning is achieved through the use of an existing computer-aided design tool.<<ETX>>

A System-Safety Process For By-Wire Automotive Systems

Steer-by-wire and other “by-wire” systems (as defined in this article) offer many passive and active safety advantages. To help ensure these advantages are achieved, a comprehensive system-safety process should be followed. Here we review standard elements of system safety processes that are widely applied in several industries and describe the main elements of our proposed analysis process for by-wire systems. The process steps include: 1) creating a program plan to act as a blueprint for the process, 2) performing a variety of hazard analysis and risk assessment tasks as specified in the program plan, 3) designing and verifying a set of hazard controls that help mitigate risk, and 4) summarizing the findings. Vehicle manufacturers and suppliers need to work together to create and follow such a process. A distinguishing feature of the process is the explicit linking of hazard controls to the hazards they cover, permitting coveragebased risk assessment.

Codesign of architectures for automotive powertrain modules

To guide design decisions in developing an optimized architecture for automotive powertrain modules, we relied upon analysis, a key to hardware-software codesign. Complicating such efforts are ongoing refinements to the underlying algorithms, ever stricter government standards, reusability demands, and late-arriving specifications for the controlled components. In our approach, configuration-level analysis lets us quickly and efficiently explore a large design space. Behavioral-level analysis validates decisions and optimizes hardware and software. Our codesign methodology extends to similar real-time embedded systems.<<ETX>>

Survey of Software Failsafe Techniques for Safety-Critical Automotive Applications

A requirement of many modern safety-critical automotive applications is to provide failsafe operation. Several analysis methods are available to help confirm that automotive safety-critical systems are designed properly and operate as intended to prevent potential hazards from occurring in the event of system failures. One element of safety-critical system design is to help verify that the software and microcontroller are operating correctly. The task of incorporating failsafe capability within an embedded microcontroller design may be achieved via hardware or software techniques. This paper surveys software failsafe techniques that are available for application within a microcontroller design suitable for use with safety-critical automotive systems. Safety analysis techniques are discussed in terms of how to identify adequate failsafe coverage. Software failsafe techniques are surveyed relative to their targeted failure detection, architecture dependencies, and implementation tradeoffs. Lastly, certain failsafe strategies for a Delphi Brake Controls application are presented as examples.

Co-Simulation Platform for Diagnostic Development of a Controlled Chassis System

This paper discusses the development and application of a closed-loop co-simulation platform for a controlled chassis system. The platform is comprised of several software packages, including CarSim(MSC Corporation), AmeSim(ImaGine Software Corporation), MATLAB/SIMULINK(Mathworks Corporation). The platform provides the ability to quickly evaluate enhancements to existing algorithms and to evaluate new control or diagnostic concepts, making it a rapid medium for development, testing and validation. The cosimulation platform was configured with real vehicle calibration data and used to test the validity/limitations of a simple model-based sensor diagnostics strategy. Using this approach, it was possible to quickly check for performance issues and consider needed corrections or enhancements without incurring the time and cost burden associated with in-vehicle testing.

A Comprehensive Hazard Analysis Technique for Safety-Critical Automotive Systems

Hazard analysis plays an important role in the development of safety-critical systems. Hazard analysis techniques have been used in the development of automotive systems become more sophisticated in functionality, design, and applied technology, the need for a more comprehensive hazard analysis approach has arisen. In this paper, we describe a comprehensive hazard analysis approach for system safety programs. This comprehensive approach involves applying a number of hazard analysis techniques and then integrating their results. This comprehensive approach attempts to overcome the narrower scope of individual techniques while obtaining the benefits of all of them.

Effective Application of Software Safety Techniques for Automotive Embedded Control Systems

Execution of a software safety program is an accepted best practice to help verify that potential software hazards are identified and their associated risks are mitigated. Successful execution of a software safety program involves selecting and applying effective analysis methods and tasks that are appropriate for the specific needs of the development project and that satisfy software safety program requirements. This paper describes the effective application of a set of software safety methods and tasks that satisfy software safety program requirements for many applications. A key element of this approach is a tightly coupled fault tree analysis and failure modes and effects analysis. The approach has been successfully applied to several automotive embedded control systems with positive results.

Hardware-Software Partitioning for Real-Time Embedded Systems

In this paper, we present an approach to hardware-software partitioning for real-time embedded systems. Hardware and software components are modeled at the system level, so that cost and performance tradeoffs can be studied early in the design process and a large design space can be explored. Feasibility factor is introduced to measure the possibility of a real-time system being feasible, and is used as both a constraint and an attribute during the optimization process. An imprecise value function is employed to model the tradeoffs among multiple performance attributes. Optimal partitioning is achieved through the use of an existing computer-aided design tool. We demonstrate the application of our approach through the design of an example embedded system.

An Evolutionary Approach to Hardware/ Software Partitioning

In this paper, we present an approach to hardware/software codesign of real-time embedded systems. Two of the difficulties associated with codesign are handling tradeoffs among multiple attributes and exploring a large design space. We use a combination of techniques from the evolutionary computation and utility theory fields to address these problem areas. A real-time microcontroller-based design example is presented to illustrate our approach.

An Efficient Wire Routing and Wire Sizing Algorithm for Weight Minimization of Automotive Systems

As the complexities of automotive systems increase, designing a system is a difficult task that cannot be done manually. In this paper, we propose an algorithm for weight minimization of wires used for connecting electronic devices in a system. The wire routing problem is formulated as a Steiner tree problem with capacity constraints, and the location of a Steiner vertex is selected for adding a splice connecting more than two wires. Besides wire routing, wire sizing is also done to satisfy resistance constraints and minimize the total wiring weight. Experimental results show the effectiveness and efficiency of our algorithm.