In the paper "Control Design for UAV Quadrotors via Embedded Model Control" [1], the authors designed a complete control unit for a UAV Quadrotor, based on the Embedded Model Control (EMC) methodology, in combination with the Feedback Linearization (FL); when applied to non-linear systems. Specifically, [1] proposes to use the FL as a novel way to design the internal model for the EMC state and disturbance predictor. To support the treatise in [1], in this report the feedback-linearized model of the UAV quadrotor leveraged in [1] is step-by-step derived.
It is well known that the conventional quadrotor is an under-actuated MIMO system. The number of the inputs is less than the degree of freedom. One approach in controlling this non-holonomic system is feedback linearization. In the frequently cited (305 times) application, the yaw and the position are selected as the controlled variables. It is reported that no singularity is found in their delta matrix, making it possible to apply the inversion within a wide range. However, we find the ignored singular zone within the range of interest. The unreported singular area can cause the failure in th…
This paper presents a mathematic dynamic model of a quadrotor unmanned aerial vehicle (QUAV) by using the symbolic regression approach and then proposes a hierarchical control scheme for trajectory tracking. The symbolic regression approach is capable of constructing analytical quadrotor dynamic equations only through the collected data, which relieves the burden of first principle modeling. To facilitate position tracking control of a QUAV, the design of controller can be decomposed into two parts: a proportional-integral controller for the position subsystem is first designed to obtain the d…
Unmanned aerial vehicles (UAVs) are finding their way into offshore applications. In this work, we postulate an original system that entails a marine locomotive quadrotor UAV that manipulates the velocity of a floating buoy by means of a cable. By leveraging the advantages of UAVs relative to high speed, maneuverability, ease of deployment, and wide field of vision, the proposed UAV$-$buoy system paves the way in front of a variety of novel applications. The dynamic model that couples the buoy, UAV, cable, and water environment is presented using the Euler-Lagrange method. A stable control sys…
Leader-Follower Formation Tracking Control of Quadrotor UAVs Using Bearing Measurements
TU/e, Eindhoven University of Technology（埃因霍温理工大学）；KTH Royal Institute of Technology（瑞典皇家理工学院）；Instituto Superior Técnico, University of Lisbon（里斯本大学高等技术学院）；University of Macau（澳门大学）
The Robotics Institute, Carnegie Mellon University（卡内基梅隆大学机器人研究所）
This paper enhances the feedback linearization controller for multirotors with a learned acceleration error model and a thrust input delay mitigation model. Feedback linearization controllers are theoretically appealing but their performance suffers on real systems, where the true system does not match the known system model. We take a step in reducing these robustness issues by learning an acceleration error model, applying this model in the position controller, and further propagating it forward to the attitude controller. We show how this approach improves performance over the standard feed…
Safety-Critical Control for Quadrotor UAVs via Decentralized Navigation Functions
Universidad Politécnica de Madrid（马德里理工大学）；School of Science and Technology, IE University（IE大学科学与技术学院）；Centre for Automation and Robotics (CSIC-UPM)（自动化与机器人中心（西班牙国家科学研究委员会-马德里理工大学））
Aggressiveness-Aware Learning-based Control of Quadrotor UAVs with Safety Guarantees
Centre for Automation and Robotics (CSIC-UPM)（自动化与机器人中心（CSIC-UPM））；Vanderbilt University（范德堡大学）；Universidad de San Andrés (UdeSA)（圣安德烈斯大学）；CONICET（阿根廷国家科学研究委员会）
Groups of unmanned aerial vehicles (UAVs) are increasingly utilized in transportation task as the combined strength allows to increase the maximum payload. However, the resulting mechanical coupling of the UAVs impose new challenges in terms of the tracking control. Thus, we design a geometric trajectory tracking controller for the cooperative task of four quadrotor UAVs carrying and transporting a rigid body, which is attached to the quadrotors via inflexible elastic cables. The elasticity of the cables together with techniques of singular perturbation allows a reduction in the model to that …
We present a trajectory tracking controller for a quadrotor unmanned aerial vehicle (UAV) configured on $SU(2)\times R^3$, and relate this result to a family of geometric tracking controllers on $SO(3)\times R^3$. The theoretical results are complemented by simulation examples, and the controller is subsequently implemented in practice and integrated with a simultaneous localization and mapping (SLAM) system through an extended Kalman filter (EKF). This facilitates the operation of the UAV without external motion capture systems, and we demonstrate that the proposed control system can be used …
Virtual Constraint for a Quadrotor UAV Enforcing a Body-Axis Pointing Direction
School of Science and Technology, IE University（IE大学科学与技术学院）；Centre for Automation and Robotics (CSIC-UPM)（自动化与机器人中心（CSIC-UPM））；Universidad de San Andrés (UdeSA)（圣安德烈斯大学）；CONICET（阿根廷国家科学研究委员会）；American College of Thessaloniki (ACT)（塞萨洛尼基美国学院）
Experimental flight tests are reported about quadrotors UAVs via a recent model-free control (MFC) strategy, which is easily implementable. We show that it is possible to achieve acrobatic rate control of the UAV, which is beyond the previous standard. The same remote controller is tested on two physical vehicles without any re-tuning. It produces in both cases low tracking error. We show that MFC is robust even when the quadrotor is highly damaged. A video footage can be found at: https://youtu.be/wtSLalA4szc
We propose a control protocol based on the prescribed performance control (PPC) methodology for a quadrotor unmanned aerial vehicle (UAV). Quadrotor systems belong to the class of underactuated systems for which the original PPC methodology cannot be directly applied. We introduce the necessary design modifications to stabilize the considered system with prescribed performance. The proposed control protocol does not use any information of dynamic model parameters or exogenous disturbances. Furthermore, the stability analysis guarantees that the tracking errors remain inside of designer-specifi…
This paper proposes a solution to the attitude tracking problem for a novel quadrotor tailsitter unmanned aerial vehicle called swiveling biplane quadrotor. The proposed vehicle design addresses the lack of yaw control authority in conventional biplane quadrotor tailsitters by proposing a new design wherein two wings with two attached propellers are joined together with a rod through a swivel mechanism. The yaw torque is generated by relative rotation of the thrust vector of each wing. The unique design of this configuration having two rigid bodies interconnected through a rod with zero torsio…
This paper gives a novel formula (Copenhagen Limit) to calculate/estimate the dynamic state error of a system without a feedforward signal. Copenhagen Limit is in the form of a limit and finds the dynamic error in an analytical solution. It can be used to design the controller in a tracking control problem. A numerical example is displayed to illustrate the accuracy of the Copenhagen Limit. Besides, the controller of a UAV (quadrotor) is designed using the Copenhagen Limit in a trajectory-tracking problem. The result of it is also demonstrated and analyzed.
To stabilize a conventional quadrotor, simplified equivalent vehicles, e.g., autonomous car, are developed to test the designed controller. Based on that, various controllers based on feedback linearization have been developed. With the recently developed concept of tilt-rotor, there lacks the simplified or equivalent model, however. Indeed, the tilt structure is relatively unusual in vehicles. In this research, we put forward a unique fictional vehicle with tilt structure, which is to help evaluate the property of the tilt-structure-aimed controllers. One phenomenon, state drift, in controlli…
In this paper, a distributed formation flight control topology for Leader-Follower formation structure is presented. Such topology depends in the first place on online generation of the trajectories that should be followed by the agents in the formation. The trajectory of each agent is planned during execution depending on its neighbors and considering that the desired reference trajectory is only given to the leader. Simulation using MATLAB/SIMULINK is done on a formation of quadrotor UAVs to illustrate the proposed method. The topology shows very good results in achieving the formation and f…
Over the past several decades there has been a constant increase in the use of Unmanned Aerial Systems (UAS). Hence, there has also been a growth in the number of control algorithms to service the many applications embodied by these vehicles. Initially UAS were made popular by the military for Reconnaissance, Intelligence, Surveillance, and Target Acquisition (RISTA) applications. Now-a-days UAS are used for everything from crop surveys to tourism. Nowhere is this more evident than with multi-rotor Unmanned Aerial Vehicle (UAV). This paper presents a survey of control methods for multi-rotor s…
