Fault tolerant control using PID structured optimal technique against actuator faults in a quadrotor UAV

This paper proposes and implements a proportional-integral-derivative (PID) structured fault tolerant controller. The fault tolerant controller is designed using linear quadratic (LQ) technique against the partial loss of control effectiveness due to the actuator fault. Compared with the conventional PID controller, the PID structure optimal controller has the ability to manipulate the multiple-input and multiple-output system (MIMO), accommodate the fault, respond fast, and eliminate the steady-state error. Performance of the proposed controller is tested based on the platform of an unmanned quadroter helicopter (known as Qball-X4).