The thesis is about developing a mission critical embedded system, specifically an RC plane with integrated autonomous control system. Through the development the appropriate fault tolerant design and implementation will be emphasized, because of the plane being mission critical, caused by the costs and motivations of it. The thesis makes a detailed presentation of the learned and used technologies, which contains fault tolerant design methods, development on embedded microcontroller, control, microcontroller communication. The actuators, control electronics, electronic system architecture and the communication between units of the designed modeling plane will be detailed.
The design chapter collects the fault modes of the separated units then using the fault tree analysis method I calculate a failure rate of the total system. With fault tree analysis I measured the reliability based on a possible self test and reconfiguration scenario based on the duplicated model.
For the whole system, so for the servo motor and servo controller, I have analysed the previously implemented functions and total system working mechanisms then I further developed it for supporting fault tolerant functions.
The servo controller software was upgraded with self tests for the essential units (CPU, memory, hard disk drive). Furthermore I developed a solution to receive commands from the communication bus and perform them.
By communicating with the servo controller I have taken measures for the different type of movements. Based on these measures I have created a static characteristic to implement a function that can detect mechanical failures of the servo motor.