About the Customer:
Our customer is an Indian Automotive Tier-1 Supplier, a pioneer in brake system development and manufacturing. Taking a lead in safety critical automotive components development, they are developing an ASIL-D compliant brake system ECU.
The Electronic parking brake ECU intended to be developed, exhibits several features that are achieved by multiple applications or algorithms. Some of these applications are dedicated to ensuring safety while others manage the comfort, system, and even certain legal aspects.
The EPB ECU has been assigned ASIL-D which is the highest level of safety criticality as per the ISO 26262 standard. The customer planned to partner with a technology provider with extensive experience in automotive embedded system development along with ISO 26262 standard proficiency. Expertise in model-based development using MATLAB was an added advantage.The top challenges were:
- High level of complexity involved in development of ASIL D solutions
- A number of safety analyses to be performed including FMEA, FMEDA, FTA and DFA in a stringent time frame
- Multiple applications to be developed, each with unique features
- MATLAB powered model-based development of applications required MATLAB expertise
Since we were providing end-to-end development of the electronic brake ECU, we followed the V-lifecycle starting with deriving the software safety requirements and functional requirements.
In the next step, our FuSa team identified the safety activities required for the execution of an ASIL D project. The activities included devising a safety plan, preparing the Development Interface Agreement (DIA) and Data Management Plan (DMP). Since it was an end-to-end project, a cross-functional team comprising hardware and software engineers along with ISO 26262 experts was set up.
After a few joint workshops with the customer’s team, we were clear with the requirements. Documentation of the system-level requirements were performed while we kick-started the concept and system phase of the safety lifecycle. Here is a snapshot of the steps included:
- Item definition: Based on the information provided by the customer we derived the item definition of the brake system. It paved the way for HARA and helped in the development of functional and technical safety requirements.
- Hazard Assessment and Risk Analysis (HARA): We assessed the malfunctions that could possibly lead to E/E system hazards and analyzed the risk associated with them.
- Safety Goals derivation: Safety goals were derived as the output of HARA analysis.
- Development of Functional Safety Requirements (FSR) and Technical Safety Requirements (TSR): We derived the FSR from the safety goals and TSR from functional safety requirements.
Based on the safety goals, TSR and FSR, system architecture was prepared which followed the software and hardware architecture along with BOM creation.Overview of the solutions and services provided:
Electronic parking brake software development
- Software & system FMEA and DFA
- Base software development including HAL & COM layer, device drivers, low level drivers & safety and diagnostics layer
- ASIL D compliant Firmware development to control motors for electronic brake ECU
- MATLAB powered development of software modules for application layer.
- Unit, integration and functional testing with reports
Electronic parking brake hardware development
- Hardware FMEDA and FIT calculation
- Hardware schematic design
- Board bring-up
- PCB layout and Gerber file generation
- Compliance, simulation, and functional testing
A Snapshot of Technical Approach for Electronic Brake ECU Development
We provided the customer with complete software and hardware development support as per ASIL D requirements. Being a one-stop destination for both software and hardware development and ISO 26262 compliance activities, we were able to provide an end-to-end solution to our customer.
The following ready-to-integrate components aided in reduced turn-around time:
- UDS protocol software stack with configuration and integration support
- Readily available board support package for Infineon Aurix family of microcontrollers
Tools and Techniques:
Codebramer ALM Tool: We used Codebeamer for application lifecycle management
MATLAB from Mathworks: MATLAB was used for software modelling
ENCO SOX: Used for safety analyses like FMEDA, DFA etc.
Tessy tool: An ISO 26262 qualified tool for unit and component testing
Polyspace: Static code analysis tool
Cadence: Tool for PCB layout