Gust disturbance alleviation with Incremental Nonlinear Dynamic Inversion

Journal of Guidance, Control, and Dynamics

Bronz

Croon

2020

Hybrid unmanned aircraft can significantly increase the potential of micro air vehicles, because they combine hovering capability with a wing for fast and efficient forward flight. However, these vehicles are very difficult to control, because their aerodynamics are hard to model and they are susceptible to wind gusts. This often leads to composite and complex controllers, with different modes for hover, transition and forward flight. In this paper, we propose incremental nonlinear dynamic inversion control for the attitude and position control. The result is a single, continuous controller, that is able to track the desired acceleration of the vehicle across the flight envelope. The proposed controller is implemented on the Cyclone hybrid UAV. Multiple outdoor experiments are performed, showing that unmodeled forces and moments are effectively compensated by the incremental control structure. Finally, we provide a comprehensive procedure for the implementation of the controller on other types of hybrid UAVs.

Section: Velocity Controlmentioning

confidence: 79%

“…The guidance of an INDI controlled quadcopter was described in previous research [21], and as INDI acceleration control is providing an abstraction layer, the Cyclone can be controlled in the same way. It starts from a certain position error, which multiplied with a gain produces the desired velocity vector.…”

Section: Guidancementioning

confidence: 99%

Incremental Control and Guidance of Hybrid Aircraft Applied to a Tailsitter Unmanned Air Vehicle

Journal of Guidance, Control, and Dynamics

Bronz

Croon

2020

“…This paper is an extension to the work presented at the Intelligent Robots and Systems conference [17]. Differences include: (1) the use of a large open jet windtunnel as a more accurate and more powerful disturbance than the fan used previously.…”

Section: Introductionmentioning

confidence: 99%

Cascaded incremental nonlinear dynamic inversion for MAV disturbance rejection

Control Engineering Practice

Croon

Chu

2018

116

Micro Aerial Vehicles (MAVs) are limited in their operation outdoors near obstacles by their ability to withstand wind gusts. Currently widespread position control methods such as Proportional Integral Derivative control do not perform well under the influence of gusts. Incremental Nonlinear Dynamic Inversion (INDI) is a sensor-based control technique that can control nonlinear systems subject to disturbances. It was developed for the attitude control of manned aircraft or MAVs. In this paper we generalize this method to the outer loop control of MAVs under severe gust loads. Significant improvements over a traditional Proportional Integral Derivative (PID) controller are demonstrated in an experiment where the quadrotor flies in and out of a windtunnel exhaust at 10 m/s. The control method does not rely on frequent position updates, as is demonstrated in an outside experiment using a standard GPS module. Finally, we investigate the effect of using a linearization to calculate thrust vector increments, compared to a nonlinear calculation. The method requires little modeling and is computationally efficient.

“…The control of the horizontal position during the hover phase is done with an incremental nonlinear dynamic inversion (INDI) controller. A detailed description of this control method, along with experiments that show the performance, is provided in previous work (Smeur, de Croon, & Chu, ). The rationale behind this controller is that the accelerometer measurement provides the sum of forces acting on the vehicle.…”

Section: Controlmentioning

confidence: 99%

Design, control, and visual navigation of the DelftaCopter VTOL tail‐sitter UAV

Wagter

Ruijsink

Journal of Field Robotics

et al. 2018

To participate in the Outback Medical Express UAV Challenge 2016, a vehicle was designed and tested that can autonomously hover precisely, takeoff and land vertically, fly fast forward efficiently, and use computer vision to locate a person and a suitable landing location. The vehicle is a novel hybrid tail-sitter combining a delta-shaped biplane fixed-wing and a conventional helicopter rotor. The rotor and wing are mounted perpendicularly to each other,and the entire vehicle pitches down to transition from hover to fast forward flight where the rotor serves as propulsion.To deliver sufficient thrust in hover while still being efficient in fast forward flight, a custom rotor system was designed. The theoretical design was validated with energy measurements, wind tunnel tests, and application in real-world missions. A rotor-head and corresponding control algorithm were developed to allow transitioning flight with the nonconventional rotor dynamics that are caused by the fuselage rotor interaction. Dedicated electronics were designed that meet vehicle needs and comply with regulations to allow safe flight beyond visual line of sight.Vision-based search and guidance algorithms running on a stereo-vision fish-eye camera were developed and tested to locate a person in cluttered terrain never seen before. Flight tests and a competition participation illustrate the applicability of the DelftaCopter concept. K E Y W O R D Saerial robotics, control, emergency response, perception, sensors