Project Context & Challenge
The development of a safety module for controlling and monitoring an automatic side door in delivery vehicles (e.g., for logistics companies like DHL) placed the highest demands on functional safety and efficiency. The goal was to optimize the daily work of mail carriers: The door should open and close fully automatically at the right time to allow unhindered “walking through” with packages without having to operate the door manually.
Since these side doors are operated with powerful motors to achieve fast cycle times, there was a massive risk of injury from crushing in the event of a malfunction. The primary challenge was to design a system that guarantees a safe state under all circumstances despite the high level of automation and speed.
The Solution / Technical Implementation (ASIL C)
The implementation was carried out consistently according to the ISO 26262 standard and met the strict requirements of Safety Integrity Level ASIL C.
- Platform: The Infineon TC234LP (32-bit AURIX) was used as the computing unit, whose lockstep architecture is predestined for such safety requirements.
- Redundancy Concept: To ensure maximum reliability, a fully redundant hardware loop was implemented. In addition, all safety-critical variables were stored redundantly in memory and checked for consistency in every calculation cycle.
- Full Automation: The control system was optimized to precisely detect movement sequences and control the door synchronously with the delivery process, while sensory monitoring (anti-pinch) was secured in real-time via the redundant path.
- Fault Tolerance: Thanks to the redundant design, single-point faults could be reliably detected to immediately transfer the system to a safe state before people are endangered.