Testing Model Based Control Systems: My Experiences and Lessons Learnt

Control systems are designed in a model-based manner using computer aided control system design tools. These are then autocoded or hand coded for implementation on board the embedded computer. In safety critical control systems it is very essential to ensure that the designer’s mental model and his design is faithfully captured in the code. Today the control system is complicated with logic, threshold comparisons and system states. In aerospace systems the code has to meet the RTCA DO 178C and DO 331 standards and this calls for additional tests. How does one ensure that the code is doing what it is supposed to do? How do you say that the testing is complete? How do you ensure that the states are correct. The DL addresses these issues with mistakes made in control system implementations, the testing method used, the automation carried out and the use of formal methods to validate the statecharts.