Development and flight test for reconfiguration of fault tolerant algorithm when actuator failure of a pixhawk based quad-copter

This paper deals with designing and verifying the performance of fault tolerant algorithm for actuator failure in Quad-copter model of small multi-copter type UAV. The fault tolerance algorithm was constructed in such a way as to control remaining state components such as posture and position while abandoning yaw axis control in case of actuator failure. Here, we derived periodic solutions by making a specific assumption and obtained controllable components, except yaw axis control. Then we configured the LQR controller as a controller to maintain the state. We apply the developed fault tolerance algorithm to the widely used open source flight control computer, Pixhawk and modify the code to check its performance. Pixhawk maintains the attitude of the airframe through a script called mc_att_control. Therefore, it is necessary to understand the mc_att_control script when applying the fault tolerance algorithm. The algorithm was designed by adding the LQR controller, derived from the periodic solution to the mc_att_control script. We used an iron bird to test the designed fault tolerance algorithm similar to the actual flight environment. Ironbird was constructed a 4-degree-of-freedom flying environment using an LM guide and a ball bearing, and we installed a balance weight to compensate for the friction generated during altitude exercise and the weight of the Ironbird structure. This paper deals with the process of applying fault tolerance algorithm to open source by understanding and modifying the attitude controller code. Through this research, it is possible to minimize the physical and human damage by ensuring the reliability of the flight and preventing the accident, which is the limitation of the open source controller.