Trajectory Generation for Underactuated Multirotor Vehicles with Tilted Propellers via a Flatness-based Method
This addresses trajectory planning for specialized multirotor designs, but it is incremental as it extends flatness-based methods to new vehicle configurations.
The paper tackles trajectory generation for underactuated multirotor vehicles with tilted propellers by showing that position and heading are flat outputs, enabling 3D trajectory following, and proposes a collocation-based numerical method verified on three robot types.
This paper considers a class of rotary-wing aerial robots with unaligned propellers. By studying the dynamics of these vehicles, we show that the position and heading angle remain flat outputs of the system (similar to conventional quadrotors). The implication is that they can be commanded to follow desired trajectory setpoints in 3D space. We propose a numerical strategy based on the collocation method to facilitate the trajectory generation. This enables convenient computation of the nominal robot's attitude and control inputs. The proposed methods are numerically verified for three multirotor robots with different dynamics. These include a tricopter with a tilting propeller, and a quadrotor and a hexacopter with unparalleled propellers.