Performance Of Quadrotor Research Articles

Experimental and Computational Investigation of Aerodynamic Interactions in Quadrotor Configurations

The influence of interactional effects on quadrotor performance in forward flight was evaluated taking into account square and diamond configurations, forward and backward tilt angles, and a range of hub spacings including overlapping blades. The analysis was based on the wind-tunnel measurements and simulations from four midfidelity computational methods and the high-fidelity tool. The outcome indicates that the efficiency of a diamond configuration improves by 5% in comparison with isolated rotors for nonoverlapping rotor spacings, while the interactions in square alignments are detrimental for all analyzed test cases with the optimum at 0.04D blade overlap. The trend is more pronounced for the backward rotor tilt with intensified interactions, for which the efficiency of the diamond configuration increases by 11% at 1.2D rotor spacing. The computational results showed good agreement with the measurement data for the forward rotor plane tilt; however, for the backward tilt angle, the spread between the calculated values, especially for torque, could be observed with the general trends maintained. The study shows negligible impact of the rotor phasing on the quadrotor efficiency.

Modified Super-Twisting Sliding Mode-based Control Design for Robust Hovering of Quadrotor

In order to allow the quadrotor to perform the hover maneuver at the desired altitude, a unique controller design based on modified super-twisting sliding mode control is proposed in this research. The proposed controller can operate even for significant state deviations from their nominal values because it is constructed inside a nonlinear framework without performing linearization of quadrotor dynamics. The control designer can assign values to the gains without knowing the precise values of the disturbance or their upper bounds due to the proposed dynamic adaptation law. This makes it easier to implement the suggested controller in real-world circumstances. Numerical simulations are used to validate the robust hovering control of the quadrotor performance in the presence of disturbance. To evaluate the controller effectiveness, the performance of the modified super twisting control is compared with that of the super twisting control, and the proposed controller outperforms the existing one.

Higher Order Sliding Mode Controller for a Quadrotor UAV with a Suspended Load

This paper highlights the significance of modelling and controlling the dynamics of a load which is suspended on the quadrotor Centre of Gravity. The oscillation of the suspended load degrades the quadrotor performance. So, the analysis of the dynamically coupled model is done and a higher order sliding mode controller is developed to counteract the effect of suspended load. A super twisting control input was derived to suppress the load swing. The results were compared with that of a conventional SMC. The conventional sliding mode controller caused unwanted oscillations called chattering in the control system. The simulation results show the effectiveness of the control system.

Hybrid controller of Lyapunov-based and nonlinear fuzzy-sliding mode for a quadrotor slung load system

In this paper, a new hybrid controller for a quadrotor slung load (QSL) system is presented. The QSL model structure has a complex and nonlinear system considering the effects of the swinging load on the quadrotor performance. However, most similar studies used linear controllers for the load position and attitude control. The lack of accurate data for the swinging load's moment of inertia and mass affects the linear controller bandwidth of the system position and increases the path tracking error, and therefore, undermines the results of such studies. In this study a new method is introduced for designing a nonlinear trajectory controller for the QSL system. The proposed method, sliding mode control (SMC), is based on the Lyapunov function and is optimized via an intelligent fuzzy-genetic algorithm. The controller consists of two control loops and one optimization loop. The inner-loop employs a Lyapunov-based controller capable of stabilizing the closed-loop system. The outer-loop is based on a nonlinear SMC and is designed to use system state variables prediction from the inner-loop system outcomes to improve the transient state parameters. The optimization loop can attain the fuzzy optimized function members coupled with SMC via a genetic algorithm. The illustrated simulation results substantiate the robustness and effectiveness of the proposed method used in eliminating the pendulum load fluctuations and their effect on the quadrotor state variables with a constant cable length.

Robust adaptive recursive sliding mode attitude control for a quadrotor with unknown disturbances

Model uncertainties, unknown disturbances, and sensors measurement noises affect the attitude tracking control performance of quadrotors. In this article, a novel robust adaptive recursive sliding mode control (ARSMC) strategy is proposed for the quadrotor to improve the attitude tracking performance and disturbance rejection. Firstly, recursive sliding mode control is introduced, including a two-layer sliding surface, an integral sliding surface, and a fast nonsingular terminal sliding surface, which are recursive. Both sliding surfaces converge to zero in turn. And the initial value of the integral sliding surface is designed to eliminate the reaching phase. Besides, the adaptive gain adjustment method is presented to make an estimate of the unknown upper bound of disturbances. It is proved that the attitude control system has the finite-time convergence and the attitude tracking error will converge to zero. A quadrotor attitude test platform is built to evaluate the proposed algorithm. For comparison, twisting controller (TC), cascade PID, and active disturbance rejection control (ADRC) algorithms are introduced. Ultimately, the efficiency and feasibility of the proposed algorithm are verified by simulation and experimental results.

An Anti-wind Modeling Method of Quadrotor Aircraft and Cascade Controller Design Based on Improved Extended State Observer

Wind disturbance may significantly reduce the flight control performance of quadrotors when flying. In order to meet high performance flight control requirements, this paper presents a quadrotor anti-wind model (QAWM) and a flight control scheme for quadrotors. The QAWM takes the influence of aerodynamic effects on the propeller, gyroscopic effect and wind disturbance into account. The model can represent more flight states including not only hovering but also flight in windy conditions even maneuver flight. A cascade control scheme with an improved extended state observer (IESO) is adopted to decompose the quadrotor flight control problem into position control loop and attitude control loop. In the attitude control loop, the IESO is used to estimate the unmodeled dynamics, parameter uncertainties and external disturbances, as well as compensate the angular velocity control. In addition, the stability of IESO and the closed loop system are proved. Simulation and experimental results show the effectiveness of the nonlinear quadrotor model and control scheme, and the control scheme can effectively improve the flight performance of quadrotors under wind disturbance even maneuver flight.

Adaptive fractional order sliding mode control for a quadrotor with a varying load

Due to their high maneuverability, quadrotors are very suitable vehicles for displacement of loads. Even so, loads can cause overweight that acts as a disturbance in momentums of inertia of quadrotor. As a result, the performance of quadrotor in path tracking will be negatively affected. In this paper, a fractional order sliding mode controller based on back-stepping method is designed to attenuate wind disturbance and effects of variations in load and momentums of inertia. The amount of load is estimated by considering an adaptive correcting coefficient in mass parameter of quadrotor, to allow the quadrotor to track the ideal path in the presence of such disturbances. Then, by using numerical simulation, the robustness of the proposed controller is shown in face of the disturbances.

Altitude Control for Variable Load Quadrotor via Learning Rate Based Robust Sliding Mode Controller

This paper aims to solve the problem of altitude control of the variable load quadrotor unmanned aerial vehicle. Generally, the controller parameters of the quadrotor are adjusted for constant load and external disturbance factors. However, whether in military fields or civilian fields, the quadrotor will encounter variable load situations, such as throwing weapons or delivering express. Variable load as a large internal disturbance factor results in control instability. Toward this end, a novel robust sliding mode controller SMC) is designed to track the desired trajectory promptly under variable load condition while restraining the chattering problem. This novel controller consists of learning rate-based sliding mode surface and inverse hyperbolic function-based adaptive sliding mode reaching law. It is worth mentioning that a mass estimation algorithm is added to the proposed novel SMC to estimate the real-time mass of the quadrotor in the air, which improves the quadrotor's performance in restraining the large variable load disturbance impact. In addition, the altitude control law is derived on the basis of the Lyapunov stability theory. Finally, the simulation and experimental results are carried out to show the effectiveness and robustness of the proposed controller in terms of altitude tracking, mass estimation, and disturbance resistance.

Design of rules for in-flight non-parametric tuning of PID controllers for unmanned aerial vehicles

Designing high performance controllers for multirotors is a rigorous task that is often solved by trial and error approach. Trial and error tuning usually results in non-optimal controller parameters. Tuning controllers based on the existing quadrotor models would result in poor performance of quadrotors due to simplifications and inaccuracies in the underlying models. In this paper optimal tuning rules for quadrotor attitude dynamics are designed, which guarantees near-optimal performance and robustness. A single in-flight run of the Modified Relay Feedback Test that takes only few seconds with guaranteed stability is enough to have near-optimal tuning of the controller. The designed tuning rule is tested experimentally in-flight on a custom-built quadrotor. The results showed significant advantages in performance and robustness due to the proposed approach.

Decoupled control design for robust performance of quadrotor

The model of (6 DOF) quadrotor is typically multivariable, nonlinear and unstable. Complex control methods have been developed by considering complete model. This paper presents a simple approach of decoupling the model into four single-input single-output subsystems i.e. longitudinal, lateral, yaw and altitude subsystems. Further, a decoupled robust control scheme is proposed for each subsystem of quadrotor, which consists of nominal control and robust compensator. The nominal control is designed by pole-placement method to achieve the desired tracking performance and robust compensator is used to handle the influence of coupling, nonlinear dynamics, external disturbance and parametric uncertainties. The robustness and convergence issues of proposed control have been investigated. The performance of proposed control method is evaluated by comparing the performance with classical centralized control, existing decentralized and decoupled control from the literature. The comparative performance results demonstrate the superiority and effectiveness of the proposed control strategy for a quadrotor UAV, while maintaining the stability even in the presence of external disturbance and parameter uncertainties.

Theoretical and Experimental Investigations on the Effect of Overlap and Offset on the Design of a Novel Quadrotor Configuration, VOOPS

The theoretical and experimental investigations of a novel configuration for a Vertical Take Off and Landing (VTOL) quadrotor system with a Vertically Offset Overlapped Propulsion System (VOOPS) is presented in this paper. The objective of the VOOPS concept is to improve the load carrying capability of the VTOL system without any increase in the footprint or reduction in endurance. This has been accomplished by overlapping the propeller blades with a vertical offset such that they don’t intersect. This way VOOPS can accommodate a larger propeller size without increase in footprint. The aerodynamics of the overlap and offset on the quadrotor performance has been analyzed using Blade Element and Momentum Theory (BEMT) and a methodology has been proposed to find their effects on thrust, drag, and power. The important design constraints for VOOPS are offset and overlap of the propellers, whose limits are evaluated using the blade-bending profile and the geometry of the propeller, respectively. The mathematical model and the design of a VOOPS quadrotor system is also presented. A quadrotor with VOOPS configuration has been designed and experimental studies have shown that the theoretical results obtained are in good agreement with the experiments. The practical implementation of VOOPS configuration and the consequences of the design changes are also presented.

Improved Quadrotor Altitude Control Design Using Second-Order Sliding Mode

AbstractIn this paper, a second-order sliding mode control (SMC) is proposed to improve the performance of quadrotor. The sliding surface of the proposed controller is based on the proportional int...

Attitude and position controller design and implementation for a quadrotor

The performance of quadrotors can be significantly disturbed in the presence of wind. In this article, a simple-to-implement attitude controller is proposed to render a robust and accurate trajecto...

Tracking Control of Quadrotor Using Static Output Feedback with Modified Command-Generator Tracker

The aim of this paper is to design a quadrotor tracking control with guaranteed performance using output feedback with modified command-generator tracker. This paper presents an approach for designing command-generator tracker control structure for position control (outer loop) and attitude control (inner loop) of quadrotor using robust performance design techniques. Modified command-generator tracker (CGT) control structure based on LQR output feedback is applied to provide zero tracking error at the outer loop. Robust performance with output feedback method is designed to guarantee stability in the presence of disturbance at the inner loop. The necessary and sufficient conditions for robust performance of quadrotor are formulated by an iterative linear matrix inequalities (LMIs) algorithm. Several simulations are performed to verify the effectiveness the proposed control method. Simulation results show that the quadrotor can track the reference signal asymptotically and maintain its stability despite the presence of disturbance.

Autonomous ship deck landing of a quadrotor using invariant ellipsoid method

This paper proposes an invariant ellipsoid-based method for the controller design and gain synthesis of a low-cost quadrotor autonomous ship deck landing system subjected to wind disturbance and measurement noise. This method optimizes the quadrotor performance, hence achieving soft landing. A complete control architecture for the quadrotor is also presented. Simulations are performed using a realistic ship deck model in the presence of measurement noise and wind disturbance with a quadrotor.

Modelling and control of a large quadrotor robot

Typical quadrotor aerial robots used in research weigh < 3 kg and carry payloads measured in hundreds of grams. Several obstacles in design and control must be overcome to cater for expected industry demands that push the boundaries of existing quadrotor performance. The X-4 Flyer, a 4 kg quadrotor with a 1 kg payload, is intended to be prototypical of useful commercial quadrotors. The custom-built craft uses tuned plant dynamics with an onboard embedded attitude controller to stabilise flight. Independent linear SISO controllers were designed to regulate flyer attitude. The performance of the system is demonstrated in indoor and outdoor flight.