Electronic Control Unit (ISO 26262, ASIL D)
In the example explored on this page, we consider the development of a Steering-Column Lock Controller (SCLC) that is to be used in a high-volume passenger car.
The design is to be developed in compliance with ISO 26262 (‘ASIL D’).
The SCLC is intended to secure the vehicle when it is not in use. It is required to operate as follows. To secure the vehicle, a locking bolt is inserted into the steering column: when the vehicle is being used, the bolt must be fully removed.
In our design, the locking bolt is to be positioned by means of a reversible DC motor. Turning the motor in one direction locks the steering column; turning the motor in the other direction unlocks the column.
The motor is to be controlled by means of an ‘H Bridge’ arrangement.
There are various possible design options for this system. One possible design is illustrated in the figure below: this is based on a ‘DecomposiTTor’ software platform.
[This page was last updated: 2018-03-05]
[This is Video 25 (out of 28 videos) from the ‘online’ version of our popular TTb course.]
Read the complete case study in ‘ERES2’
The Second Edition of ‘The Engineering of Reliable Embedded Systems’ (ERES2), documents an industry-proven approach to the development of software for reliable, real-time embedded systems, based on the use of ‘Time Triggered’ (TT) architectures.
What distinguishes TT approaches is that it is possible to model the expected system behaviour precisely. This means that: [i] during the development process, we can demonstrate that all of the requirements have been met; and [ii] at run time, we can detect problems very quickly.
The end result is that we can have a high level of confidence that a TT system will either: [i] operate precisely as required; or [ii] move into an appropriate state if a problem occurs.
The above characteristics mean that appropriately-implemented TT systems provide a particularly effective means of meeting the requirements of various international safety standards.
In order to illustrate how the TT techniques presented in ERES2 can be employed in practical designs, five detailed case studies are included. These studies describe the development of embedded control and monitoring systems for the following products:
- an industrial alarm sounder unit (IEC 61508, SIL 2);
- a domestic washing machine (IEC 60730, Class B);
- a hospital radiotherapy machine (IEC 62304, Class C);
- a steering-column lock for a passenger car (ISO 26262, ASIL D);
- an aircraft jet engine (DO-178C, Level A).
Complete your cost-effective ISO 26262 design successfully using a SafeTTy Solutions™ package
Our SafeTTy Solutions™ packages are designed to help your development team produce a safety-related embedded system quickly and cost-effectively, in compliance with one or more international safety standards (ISO 26262, IEC 61508, DO-178C, IEC 62304, IEC 60730 …).
SafeTTy Solutions packages are based on TT designs and include carefully-selected combinations of our various products and services.
SafeTTy Solutions packages include an appropriate ReliabiliTTy® Technology Licence.
Learn more about SafeTTy Solutions packages …