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The control of a quadrotor unmanned aerial vehicle (UAV) is a challenging problem because of its highly nonlinear dynamics, under-actuated nature and strong cross-couplings. To solve this problem, this paper aims to propose a robust control strategy, based on a concept of active disturbance rejection control (ADRC).

The altitude/attitude dynamics of a quadrotor is reformulated into the ADRC framework. Three distinct variations of the error-based ADRC algorithms, with different structures of generalized extended state observers (GESO), are derived for the altitude/attitude trajectory-following task. The convergence of the observation part is proved based on the singular perturbation theory. Through a frequency analysis and a quantitative comparison in a simulated environment, each design is shown to have certain advantages and disadvantages in terms of tracking accuracy and robustness. The digital prototypes of the proposed controllers for quadrotor altitude and attitude control channels are designed and validated through real-time hardware-in-the-loop (HIL) co-simulation, with field-programmable gate array (FPGA) hardware.

The effects of unavailable reference time-derivatives can be estimated by the ESO and rejected through the outer control loop. The higher order ESOs demonstrate better performances, but with reductions of stability margins. Time-domain simulation analysis reveals the benefits of the proposed control structure related to classical control approach. Real-time FPGA-based HIL co-simulations validated the performances of the considered digital controllers in typical quadrotor flight scenarios.

The conducted study forms a set of practical guidelines for end-users for selecting specific ADRC design for quadrotor control depending on the given control objective and work conditions. Furthermore, the paper presents detailed procedure for the design, simulation and validation of the embedded FPGA-based quadrotor control unit.

In light of the currently available literature on error-based ADRC, a comprehensive approach is applied here, which includes the design of error-based ADRC with different GESOs, its frequency-domain and time-domain analyses using different simulation of UAV flight scenarios, as well as its FPGA-based implementation and testing on the real hardware.

The purpose of this paper is to give reviews on the platform modeling and design of a controller for autonomous vertical take-off and landing (VTOL) tilt rotor hybrid unmanned aerial vehicles (UAVs). Nowadays, UAVs have experienced remarkable progress and can be classified into two main types, i.e. fixed-wing UAVs and VTOL UAVs. The mathematical model of tilt rotor UAV is time variant, multivariable and non-linear in nature. Solving and understanding these plant models is very complex. Developing a control algorithm to improve the performance and stability of a UAV is a challenging task.

This paper gives a thorough description on modeling of VTOL tilt rotor UAV from first principle theory. The review of the design of both linear and non-linear control algorithms are explained in detail. The robust flight controller for the six degrees of freedom UAV has been designed using H-infinity optimization with loop shaping under external wind and aerodynamic disturbances.

This review will act as a basis for the future work on modeling and control of VTOL tilt rotor UAV by the researchers. The development of self-guided and fully autonomous UAVs would result in reducing the risk to human life. Civil applications include inspection of rescue teams, terrain, coasts, border patrol buildings, police and pipelines. The simulation results show that the controller achieves robust stability, good adaptability and robust performance.

The review articles on quadrotors/quadcopters, hybrid UAVs can be found in many literature, but there are comparatively a lesser amount of review articles on the detailed description of VTOL Tilt rotor UAV. In this paper modeling, platform design and control algorithms for the tilt rotor are presented. A robust H-infinity loop shaping controller in the presence of disturbances is designed for VTOL UAV.

The purpose of this paper is to propose a new approach for robust control of an autonomous quadrotor unmanned aerial vehicle (UAV) in automatic take-off, hovering and landing mission and also to improve the stabilizing performance of the quadrotor with inherent time-varying disturbance.

First, the dynamic model of the aerial vehicle is mathematically formulated. Then, a combination of a nonlinear backstepping scheme with the intelligent fuzzy system as a new key idea to generate a robust controller is designed for the stabilization and altitude tracking of the vehicle. For the problem of determining the backstepping control parameters, a new heuristic algorithm, namely, Gravitational Search Algorithm has been used.

The control law design utilizes the backstepping control methodology that uses Lyapunov function which can guarantee the stability of the nominal model system, whereas the intelligent system is used as a compensator to attenuate the effects caused by external disturbances. Simulation results demonstrate that the proposed control scheme can achieve favorable control performances for automatic take-off, hovering and landing mission of quadrotor UAV even in the presence of unknown perturbations.

This paper propose a new robust control design approach which incorporates the backstepping control with fuzzy system for quadrotor UAV with inherent time-varying disturbance. The originality of this work relies on the technique to compensate the disturbances acting on the quadrotor UAV. In this new approach, the fuzzy system is introduced as an auxiliary control effort to compensate the effect of disturbances. Because the proposed control technique has the capability of robustness against disturbance, thus, it is also suitable to be applied for a broad class of uncertain nonlinear systems.

With the purpose of clearing up the risk to rotor blades, this paper develops a quad ducted‐fan helicopter using four ducted‐fans instead of four rotor blades in a quad rotor helicopter.

Auto hovering test, auto cruise test, and altitude control simulations were conducted to estimate the flight performance of the quad ducted‐fan helicopter.

Flight performance of the test quad ducted‐fan helicopter is almost same as a commercial quad rotor helicopter, and it succeeds to decrease the risk to the rotor blade. However, endurance is shorter than that of the quad rotor helicopter, because of the ducted‐fan characteristics.

The test quad ducted‐fan helicopter can fly for about four minutes with two packs of fourcell (16.8 V)‐2200 mAh Lipo batteries, and it needs about 3.3 times as much energy as quad rotor helicopter. The authors will improve the performance of quad ducted‐fan helicopter by aerodynamics analysis and design of ducted‐fan system

This is expected to reduce the risk of rotor blade mounted on multi rotor helicopter.

The research will facilitate the development of safety autonomous multi‐copters in various civilian applications.

The research purpose is to realize safety multi‐copter flight using ducted‐fan instead of rotor blade.

Dowty Boulton Paul have been involved in the electrical signalling of aircraft control surface actuators since 1956 and would claim responsibility for the first aircraft to fly with such control in 1957. Figure 1 shows that Dowty have been continuously working on fly‐by‐wire projects since that time.

FOREMOST among designers and manufacturers of ejection seats is the Martin‐Baker company which had an impressive display at Farnborough showing how their expertise had, over the years, saved close on 5,500 aircrew lives and with the incorporation of even more advanced equipment, will given flying personnel the confidence in systems fitted to aircraft of the future. A wide variety of aircraft now uses this company's equipment, perhaps the most significant of recent contracts having been the award from the US Navy to develop and produce the Navy Aircrew Common Ejection Seat (NACES). This new seat employs an on‐seat sensory system and microprocessor controlled electronic sequencer to enable it to respond to the flight conditions at the time of ejection and to control the operation of the seat to achieve the maximum aircrew recovery capability. It will be installed in the McDonnell Douglas F/A 18 Hornet and T‐45 Hawk and in the Grumman F‐14D Tomcat and A‐6E (Upgrade) Intruder.

The latest expertise in escape systems was shown on the Martin‐Baker stand at the Paris Show, highlighted by the company's Mk 14 which is the world's first microprocessor controlled electronic ejection seat. Currently undergoing testing is the variant for the United States Navy Aircrew Common Ejection Seat (NACES) programme, which will be standard equipment for the F/A Hornet, F‐14 Tomcat, T‐45 Goshawk and A6F Intruder. Versions are also being proposed for the European Figh‐ter Aircraft, French Rafale B and the USAF Advanced tactical Fighter.

Despite of the numerous characteristics of the multirotor unmanned aircraft systems (UASs), they have been termed as less energy-efficient compared to fixed-wing and helicopter counterparts. The purpose of this paper is to explore a more efficient multirotor configuration and to provide the robust and stable control system for it.

A heterogeneous multirotor configuration is explored in this paper, which employs a large rotor at the centre to provide majority of lift and three small tilted booms rotors to provide the control. Design provides the combined characteristics of both quadcopters and helicopters in a single UAS configuration, providing endurance of helicopters keeping the manoeuvrability, simplicity and control of quadcopters. In this paper, rotational as well as translational dynamics of the multirotor are explored. Cascade control system is designed to provide an effective solution to control the attitude, altitude and position of the rotorcraft.

One of the challenging tasks towards successful flight of such a configuration is to design a stable and robust control system as it is an underactuated system possessing complex non-linearities and coupled dynamics. Cascaded proportional integral (PI) control approach has provided an efficient solution with stable control performance. A novel motor control loop is implemented to ensure enhanced disturbance rejection, which is also validated through Dryden turbulence model and 1-cosine gust model.

Robustness and stability of the proposed control structure for such a dynamically complex UAS configuration is demonstrated with stable attitude and position performance, reference tracking and enhanced disturbance rejection.

Up until the 1970s the number of instruments on an aircraft's flight deck had been increasing over many years as technical developments made it possible to present more information about the aircraft and its systems. Particularly on large transport aircraft, the multiplicity of displays and their associated controls kept a sizeable flight crew fully occupied controlling and monitoring all the functions.

Unmanned aerial vehicles (UAVs) have a wide variety of applications such as surveillance and search. Many of these tasks are better executed by multiple UAVs acting as a group. One of the main problems to be tackled in a high‐density UAV traffic scenario is that of collision avoidance among UAVs. The purpose of this paper is to give a collision avoidance algorithm to detect and resolve the conflicts of projected path among UAVs.

The collision avoidance algorithm developed in the paper handles multiple UAV conflicts by considering only the most imminent predicted collision and doing a maneuver to increase the line‐of‐sight rate to avoid that conflict. After the collision avoidance maneuver, the UAVs fly to their destinations via Dubins shortest path to minimize time to reach destination. The algorithm is tested on realistic six degree of freedom UAV models augmented with proportional‐integral controllers to hold altitude, velocity, and commanded bank angles.

The paper shows, through extensive simulations, that the proposed collision avoidance algorithm gives a good performance in high‐density UAV traffic scenarios. The proposed collision avoidance algorithm is simple to implement and is computationally efficient.

The algorithm developed in this paper can be easily implemented on actual UAVs.

There are only a few works in the literature that address multiple UAV collision avoidance in very high‐density traffic situations. This paper addresses very high‐density multiple UAV conflict resolution with realistic UAV models.