Shipboard Landing Control Enabled by an Uncertainty and Disturbance Estimator

Abstract

This paper presents an autonomous landing control approach for a quadrotor unmanned aerial vehicle subject to wind disturbance and three-dimensional movements of the landing platform. To achieve an accurate relative position estimation of the quadrotor to the landing platform, a camera, a distance sensor, and a single-board computer are integrated to the quadrotor. The coordinate transformation is introduced to deal with the constraint that only the relative position information is available. The impacts of unknown ship motions are treated as part of the lumped uncertainty terms. Then, the uncertainty and disturbance estimator-based controllers are developed to achieve the accurate relative position control of the quadrotor while dealing with unknown ship motions, ground effect, state couplings, and external disturbances. The uncertainty and disturbance estimator filter is designed based on the internal model principle to enhance the performance of the developed controller. The reference model of the relative altitude controller is modified to ensure the accurate tracking of descending commands. To maximize the capability of the developed controller, a parameter selection guideline based on the derived ship heave acceleration spectrum is provided. Both numerical simulations and flight experiments are carried out to demonstrate the effectiveness of the developed approach.

Computationally Efficient Force and Moment Models for Propellers in UAV Forward Flight Applications

“…In the context of control of multirotor vehicles, the typical modelling approach has been to use a hover or 'static' model, that is, the thrust and rotor torque are proportional to the square of the propeller rotation rate, and to neglect H-force, pitching and rolling moments [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33]. As shown in [15], this model breaks down when a quadrotor flies at moderate speeds.…”

Autonomous Landing of a Quadrotor on a Moving Platform via Model Predictive Control

“…The latter produces unnecessary consumption of both energy and time. The work in [14] regards the unknown motion of the ship and winds as external disturbances to the process of controlling the quadrotor landing a shipboard. The authors use an uncertainty and disturbance estimator to guess the disturbances and compensate them to the control commands.…”

Autonomous Quadcopter Precision Landing Onto a Heaving Platform: New Method and Experiment

“…Compared with other mobile landing platforms, a ship deck environment makes the landing task more challenging due to the influences of the sea waves and strong disturbances such as the wind. Dealing with such an issue, the authors of [25]- [28] proposed different methods using different control techniques, including PID [25], sliding mode control [26], robust linear feedback control [27]. However, these studies only stopped at verifying the proposed algorithm through numerical simulations.…”