Impact of Redundant Inputs on Octorotor Using Linear Quadratic Regulator

Distinct from a standard quadrotor, an octorotor features eight rotors, which introduces input redundancy into such unmanned aerial vehicle (UAV) systems. It is easy to know that redundant rotors can boost system reliability and improve payload capacity. Nonetheless, evaluating the impact of each additional rotor remains an unresolved issue. In this paper, focusing on the linear quadratic regulator (LQR) problem, we show that redundant rotors add more columns to the input matrix. Given that the system matrix is unaltered and the original columns of the input matrix remain incorporated into the new one, these additional columns do not affect the controllability of an already controllable system. Our paper goes beyond controllability, showing that a greater number of rotors improves performance for the LQR problem. To illustrate this point, numerical experiments are conducted to highlight the contributions of these redundant rotors.