8. Observer-based Feedback Linearization Control of a Quadrotor Subjected to Sensor Noise

The aim of this chapter is to propose an observer-based feedback linearization controller for nonlinear quadrotor dynamics to track the given reference when subjected to internal and external noise sources. First, the nonlinear model of the quadrotor is derived with rotational subsystems including rotational rates. Double-loop sequential controller is designed with feedback linearization control and linear quadratic regulator sub-blocks. Quadrotor is subjected to noise sources. To eliminate the noise, an observer is designed in addition to the control loops. The proposed method is tested under two scenarios that include from 0 initial point to any positive arbitrary reference and from any negative arbitrary states to 0 reference. Performance of the proposed method is evaluated with absolute error, signal-to-noise ratio, and standard deviation of error analyses for the noisy references. According to the results, the proposed method can control the nonlinear quadrotor dynamics, whereas the method reduced the absolute noise from 0.6 [rad] to 0.15 [rad] and reduced the standard deviation of the error from 0.17 [rad] to 0.05 [rad] with an increment in the signal-to-noise ratio up to 25.5. The aim of this chapter is to propose a controller for nonlinear quadrotor dynamics that can handle sensor errors with the aid of an observer scheme.