Relative kinematics for a jerk-level trajectory generation system

Using electric vertical takeoff and landing (eVTOL) aircraft for urban air mobility requires a high level of maneuverability and tracking accuracy from the flight guidance systems. This can be achieved by constructing a high-order desired trajectory, in order to provide jerk-level feedforward commands and acceleration-level relative kinematics. In this paper, we perform a noise analysis on a trajectory system where relative kinematics are computed numerically, and we show the resulting noise effects. We then present an analytical alternative which improves the noise sensitivity. Additionally, we develop a smoothing strategy for obtaining a high-order parametrization of a trajectory designed with low-order clothoid curves. The methods presented in the paper are tested and validated in closed-loop simulations and through flight tests on a 700 kg medical-evacuation eVTOL aircraft. The results of these tests are presented and discussed.