Sensors integration in embedded systems

Sensors/actuators are critical components of several Complex Embedded Systems (CES). In these CES a fault in the sensors or actuators can trigger the incidence of catastrophic events. Sensor / actuator faults detection is difficult and impacts critically the system performance. Subsystem or Embedded Processing Component (EPC), integration testing with sensor or actuator is required to assure that the ‘Subsystem under test (SUT)’ meets the specifications. Several researchers have addressed software integration issues only; however sensors /actuators integration issues were not addressed adequately. This paper focuses on the integration testing of sensors / actuators in ES. The sensor integration with EPC is viewed as identification of faulty communication channel within SUT. The Sensor and EPC models are developed based on and are modified for incorporating faults in the communication channel between them. A faulty communication channel is modelled by a “faulty process Ψ” that changes the operations or possibly modifies events between the fault-free processes, while the components are assumed to be fault free. The functional tests are important in verifying system and their reuse in integration testing correctly identifies the known and tested system requirements. Comparing the observed output in the communication channel with expected response identifies the fault(s) in the channel and provides integration test verdict: pass or fail. An example illustrates the application of functional testing for integration of sensor.