Safety Validation Using AADL System Architecture Models

Most of the embedded systems used in avionics and automotive industries are safety critical in nature. Safety validation of these systems are challenging inspite of significant advances in the field of system and software engineering. In our previous work, real time monitoring of system level parameters at hardware-software integration test environment could capture safety critical errors, which could have led to hazardous system behaviour. However, parameters to be monitored were captured from design and coding phase, resulted in lot of rework. The situation could have been avoided if model based software engineering was followed, wherein system engineer and safety analyst could base their work on a common model. Hence, architecture Analysis and Design Language (AADL) along with its error annex were selected for modelling and a systematic method for modelling a system from safety point of view was arrived at and reported in [7]. But translation of these into test cases which could be used for system safety validation is still in infancy. This paper focuses on automatic generation of safety validation test cases from AADL model enriched with error behaviour. The method is presented with Isolette, a well-known AADL model case study.