Nonlinear 3D Guidance and Control Strategy for Quadrotor Path Following

This work delves into designing a guidance and control strategy for a quadrotor to follow an arbitrarily smooth, prespecified path in three-dimensional space. Motivated by the interceptor guidance literature, this work develops a three-dimensional guidance law that accounts for varying speed, thereby distinguishing it from conventional interceptor guidance laws. A virtual reference point moving along the desired path acts as a dynamic target, pursuing which results in a path-following behaviour. The guidance law first aligns the quadrotor's velocity vector with the line-of-sight and then steers to nullify the relative distance to the virtual reference point. The proposed controller is based on the nonlinear kinematics engagement and the nonlinear quadrotor dynamics. The stability of the controller is mathematically guaranteed. Numerical simulations have been performed for different specified paths to validate the working of the proposed guidance and control strategy.