Unmanned Aerial Vehicle Control System Research Articles

Adaptive Sliding Mode Attitude Control of Quadrotor UAVs Based on the Delta Operator Framework

In this paper, a novel adaptive sliding-mode control algorithm is proposed for the attitude control of quadrotor unmanned aerial vehicles (UAVs) under the delta operator framework. First, the delta operator technique is used to discretize the attitude control systems of a quadrotor UAV. Then, based on the linear matrix inequality technique, a linear sliding surface is designed to ensure the asymptotical stability of the quadrotor UAV attitude control system during the sliding motion process. Second, by the estimated external disturbance using a radical basis function (RBF) neural network, an adaptive sliding-mode attitude controller is designed such that the states of the quadrotor UAV attitude systems can be driven towards the desired sliding surface, and thus the attitude control objective of the qudarotor UAV is achieved. Compared with the traditional adaptive sliding-mode control algorithm, the proposed adaptive sliding-mode control algorithm can effectively realize the attitude control of a quadrotor UAV subject to strong disturbances and couplings. Finally, comparisons of the simulation results verify the effectiveness and superiority of the control algorithm proposed in this paper.

무인항공기 이동 목표물 추적 비행 및 착륙 성능 개선을 위한 입력 신호 변형 기반의 제어 보조 시스템

In this study, a novel input signal transformer is introduced to remove an overshoot and steady-state error that hinder stable tracking and landing of an unmanned aerial vehicle (UAV) based on image recognition, and the performance is verified. The Input Signal Transformer (IST) is designed in the shape of a sigmoid function to attenuate or amplify the input signal to resolve the aforementioned problems. For the verification of the UAV control system based on the IST, the UAV, target, and sensors were implemented in a virtual environment using the robot operating system (ROS). And data exchange structure and control system were built by the ROS-based message communication. A simulation was performed to confirm the elimination of the overshoot and steady-state error when the UAV to which the above control system was applied tracks and lands a fixed target and a moving target. As a result of the simulation, when the IST was not used, the UAV performed an unstable because of the overshoot and could not land on the target by the steady-state error. Conversely, in the case of using IST, it was confirmed that the flight was stable and landed successfully.

Formation of unmanned aircraft trajectory when flying around prohibited areas

Considered the problem of flying over restricted areas by an unmanned aerial vehicle (UAV), which have various shapes and restrictions, set on the basis of the international airspace classification system for aviation in accordance with the Chicago Convention and the recommended principles for the formation of forbidden zones, rules for creating a flight route along forbidden zones and actions in case of border violations of restricted areas. The problem of analytical synthesis of the control acceleration of an unmanned aerial vehicle (UAV) is solved during its flight along a route passing along the boundaries of the forbidden zone of a given shape, along a given trajectory, which consists of subsequent segments located at the same height relative to the earth’s surface, in a given coordinate system. The optimal control synthesis problem is solved as an analytical definition of the optimal control of a linear non-stationary system based on the quadratic quality functional. A mathematical model of UAV motion in the horizontal plane is proposed, in the form of a system of ordinary differential equations in the Cauchy form. A law for measuring the control acceleration of the UAV’s center of mass is obtained on the basis of specifying the minimized quality functional and the corresponding constraints, which is a feature of the considered method of solving the problem. The proposed quality functional takes into account the parameters of coordinates and speed of the UAV, which correspond to the given points in the airspace, which characterize the necessary trajectory for flying around the restricted area. The derived mathematical dependences make it possible to implement them on board a UAV and minimize energy costs when guiding a UAV moving through specified points in space. Computer modeling of the derived analytical results, mathematical dependencies representing the optimal trajectory of the UAV flight along the boundaries of the forbidden zone, as well as the corresponding processes of changing the control acceleration and speed of the UAV movement was carried out, which made it possible to draw conclusions about the efficiency of the proposed method and the feasibility of its further use as a basis. for the initial stage of the synthesis of the UAV control system.

WAYS OF INCREASING THE RELIABILITY OF MESSAGE TRANSMISSION IN INFORMATION AND COMMUNICATION SYSTEMS USING ONE-WAY RADIO CHANNELS

Modern information and communication systems which use one-way radio channels have the main task to maximize the reliability and information transmission stealth. This task becomes more relevant in conditions of the radio-electronic warfare and growing of the cyber incidents with wireless vulnerabilities exploitation. This solution is useful for Internet of Things technologies with one-way interaction protocols and unmanned aerial vehicle control systems for organization and critical infrastructure cyber security support.The purpose of this work is the fading of possible ways for increasing of the message transmission reliability in the information and communication systems with one-way radio channels.The examples of digital modulation methods applications, interference-resistant coding which are used in modern information and communication technologies with one-way radio transmission are considered in the article. In the work were received results of digital modulation methods and interference-resistant coding analysis with minimum bit error rate criterion. The usage futures of combined random coding which is based on interference-resistant and stochastic coding combination were researched.Standard random bit generators were tested by the NIST Statistical Test Suite 2.1.2 application.This research results give us the possibility to increase the reliability of message transmission by way using binary phase-shift keying in combination with majority coding. In this case we should solve tasks to improve the phase estimation schemes of received signal and optimal choice of majority coding redundancy.In order to increase the reliability and information stealth of message transmission the using of combined random coding was proposed. At the same time, we recommend to use Blum-Blum-Shub random bit generator for the codebook creating. Blum-Blum-Shub random bit generator was chosen according to estimation results, obtained with the help of NIST Statistical Test Suite.

Instruction Sender Authentication Utilizing Touch Screen Operation Action Fingerprint for UAV Systems

Instruction sender authentication of UAV (Unmanned Aerial Vehicle) control is critical for the secure operation of UAV systems. By exploring user touch action characteristics of the user interaction with the UAV control mobile terminal, this paper proposes a novel instruction sender continuous authentication framework for UAV control systems. In particular, we first obtain the touch screen data in real time from the interaction with the mobile device screen of a user when he controls the UAV. Then we create a polynomial to fit the touch trajectory on the screen of the user, and use the least square method to obtain the optimal estimate of the polynomial coefficients. Finally, we mark the grid area covered by the polynomial to extract the user’s touch screen operation action fingerprint(OAF), and employ the fuzzy extractor method to realize the identity authentication of the sender with certain error tolerance. Extensive experiments are conducted to illustrate the authentication performance of the proposed authentication framework in terms of false acceptance rate, false rejection rate and equal-error rate.

Синтез адаптивного скользящего режима управления полетом квадрокоптера в условиях переменной нагрузки и помех

Adaptive sliding control mode of an unmanned aerial vehicle (UAV) has been synthesized using neural networks to identify unknown factors acting on UAV. The MATLAB SIMULINK software was used to simulate the operation of the UAV control system. The simulation of the operation of the UAV location tracking system and UAV movement under the influence of unknown external forces of both constant magnitude and external forces varying according to a linear law is performed. An assessment of the performance of the UAV control system under the influence of random interference is given.

Using of the SPSA method to improve the accuracy of the UAV following a given route under the action of wind loads

In the modern world, UAVs (unmanned aerial vehicles) are increasingly used in everyday life in solving civilian tasks. One of the main applications of UAVs is data collection with their reference to a given coordinate system. For example, for the task of aerial photography, it is necessary to accurately link each image to the global coordinate system. In addition to the exact location of coordinates, it is worth the exact movement of a given route, to collect data of exactly those places that are needed. Thus, it is very important to ensure the minimum deviation of the UAV from the given route under the conditions of external disturbances (wind disturbances) acting on it. The article describes a procedure for assessing wind speed and direction for a UAV control system using the SPSA method. The simulation results of the algorithm operation, confirmed during flight tests on an ultralight UAV with an ardupilot autopilot, are presented.

Identification of UAV model parameters from flight and computer experiment data

The object of research in the article is various well-known approaches and methods of structural and parametric identification of dynamic controlled objects - unmanned aerial vehicles (UAVs). The subject of the research is the parameters of linear and nonlinear mathematical models of spatial and isolated movements, describing the dynamics and aerodynamic properties of the UAV and obtained both from the results of flight experiments and using computer object-oriented programs for 3-D UAV models. The goal is to obtain mathematical models of UAV flight dynamics in the form of differential equations or transfer functions, check them for reliability and the possibility of using them in problems of synthesis of algorithms for automatic control systems of UAVs. Tasks to be solved: evaluation of the analytical (parametric), direct (transient), as well as the identification method using the 3-D model of the control object. Methods used structural and parametric identification of dynamic objects; the determination of static and dynamic characteristics of mathematical models by the type of their transient process; the System Identification Toolbox package of the MatLab environment, the Flow Simulation subsystem of the SolidWorks software and the X-Plane software environment. The experimental parameters of UAV flights, as well as the results of modeling in three-dimensional environments, are the initial data for the identification of mathematical models. The following results were obtained: the possibility of analytical and computer identification of mathematical models by highly noisy parameters of the UAV flight was shown; the mathematical models of UAVs obtained after identification is reliable and adequately reproduce the dynamics of a real object. A comparative analysis of the considered UAV identification methods is conducted, their performance and efficiency are confirmed. Conclusions. The scientific novelty of the result obtained is as follows: good convergence, reliability and the possibility of using the considered identification methods for obtaining mathematical models of dynamic objects to synthesize algorithms for automatic control systems of UAVs is shown.

FEATURES OF RISK ASSESSMENT IN THE CREATION OF UAV FOR VARIOUS PURPOSES

One of the perspective directions of the development to modern aviation is connected with designing and producing unmanned aerial vehicles (UAV) of various functionalities for applying in military and civilian spheres. The syntheses of UAV control systems, regardless of their type and purpose presumes the creation of adequate mathematical models, first of all adequate aerodynamic mathematical models. In the paper results that forms and justify the aerodynamic mathematical model and as well as the results of building a general mathematical model of the longitudinal movement of the perspective UAV are presented. In the article on the basis of the analysis of the reasons of involvement in performance of research and development works the basic risks of the indirect factors and possible negative scenarios of performance of projects of creation of samples of aviation equipment are defined. Based on the results of the analysis of risk-forming factors, the risk indicators of the projects of creation (modernization) of aircraft models are substantiated. A methodical approach to the criterion assessment of risk indicators at the stages of research and development work on the development (modernization) of aircraft is proposed

The Mathematical Model for Research of the UAV Longitudinal Moving

The paper presents one of the perspective directions of the development to modern aviation, which is connected with designing and producing unmanned aerial vehicles (UAV) of various functionalities for applying in both military and civilian spheres. The syntheses of UAV control systems, regardless of their type and purpose presumes creation of adequate mathematical models, first of all adequate aerodynamic mathematical models. In the paper results that forms and justify the aerodynamic mathematical model and as well as the results of building a general mathematical model of the longitudinal movement of the perspective UAV are presented. Also factors that forms the mathematical model on given aerodynamic, geometric, mass and inertial data for a hypothetical perspective altitude long-range UAV are submitted. Assessment of the impact of these data on the dynamic, temporal, and logarithmic frequency response UAV also has been given in this paper.

Modeling and Design of an Aircraft-Mode Controller for a Fixed-Wing VTOL UAV

Vertical takeoff and landing (VTOL) is an essential feature of unmanned aerial vehicles (UAVs). On the one hand, VTOL can expand and enhance the applications of UAVs; yet, on the other hand, it makes the design of control systems for UAVs more complicated. The most challenging demand in designing the control system is to achieve satisfactory response sharpness of fixed-wing UAVs to control commands and ensure that the aircraft mode channels are effectively decoupled. In this work, a six-degree-of-freedom (6-DoF) model with forces and moments is established based on the aerodynamic analysis, which is carried out through computational fluid dynamics (CFD) numerical simulation. The improved proportional derivative (PD) controller based on the extended state observer (ESO) is proposed to design the inner-loop attitude control, which increases the anti-interference ability for internal and external uncertainty of the UAV system. The motion equations of the UAV are established and divided into independent components of longitudinal and lateral motion to design the outer loop control law under minor disturbance conditions. A total energy control system (TECS) for the longitudinal height channel is proposed, which separates speed control and track control. L1 nonlinear path tracking guidance algorithm is used for lateral trajectory tracking so as to improve curve tracking ability and wind resistance. Effectiveness of this approach is proved by actual flight experiment data. Finally, a controller based on angular velocity control is designed to prevent the attitude and head reference system (AHRS) from malfunctioning. Its effectiveness is verified by the response test of the control system.

Autonomous landing of a quadrotor on a moving platform using vision-based FOFPID control

AbstractThis research deals with the autonomous landing maneuver of a quadrotor unmanned aerial vehicle (UAV) on an unmanned ground vehicle (UGV). It is assumed that the UGV moves independently, and there is no communication and collaboration between the two vehicles. This paper aims at the design of a closed-loop vision-based control system for quadrotor UAV to perform autonomous landing maneuvers in the possible minimum time despite the wind-induced disturbance force. In this way, a fractional-order fuzzy proportional-integral-derivative controller is introduced for the nonlinear under-actuated system of a quadrotor. Also, a feedback linearization term is included in the control law to compensate model nonlinearities. A supervisory control algorithm is proposed as an autonomous landing path generator to perform fast, smooth, and accurate landings. On the other hand, a compound AprilTag fiducial marker is employed as the target of a vision positioning system, enabling high precision relative positioning in the range between 10 and 350 cm height. A software-in-the-loop simulation testbed is realized on the windows platform. Numerical simulations with the proposed control system are carried out, while the quadrotor system is exposed to different disturbance conditions and actuator dynamics with saturated thrust output are considered.

Analytical Synthesis of Control Acceleration of Unmanned Aerial Vehicle

. The problem of analytical synthesis of the control acceleration for an unmanned aerial vehicle (UAV) during its flight along a complex trajectory, consisting of sequentially located horizontal flight sections, located at different heights relative to the earth's surface has been solved in the paper. The problem has been solved as an analytical definition of the optimal control of a linear non-stationary system for a specified minimized quality functional. The mathematical model of the system is presented in the form of differential equations of UAV motion in the vertical plane of a fixed coordinate system related to the earth's surface. A feature of the proposed methodology for solving the problem is the substantiation of the original form of the minimized functional and parameters included in the law of variation of the control acceleration obtained by known methods. As the components of the quality functional, the values of coordinates and velocity of the UAV are considered and they are specified at the corresponding points in space through which the UAV path must pass, in order to obtain the optimal curvature of the trajectory. The derived mathematical dependences make it possible to implement them on board of an aircraft and, ultimately, solve the problem of ensuring the minimum energy consumption when controlling an object (UAV). Computer simulation of the analytically obtained results in the form of the UAV flight trajectory and the processes of changing its acceleration and speed have shown the efficiency of the proposed technique and the prospects of its use at the initial stage of the synthesis of the UAV control system.

ДОСЛІДЖЕННЯ АЛГОРИТМІВ НАВІГАЦІЇ ТА КАРТОГРАФІЇ ДЛЯ БЕЗПІЛОТНОГО ЛІТАЛЬНОГО АПАРАТУ

The methods of navigation of an unmanned aerial vehicle (UAV) are considered. The main focus is on navigation methods that reduce the operator's activities to setting the current task and monitoring the operation of the UAV. The UAV must independently assess the environment and plan its path, including in the presence of other moving objects. The solution of control and navigation tasks for UAVs without a remote control significantly facilitates the operator's task, but requires the development of a UAV control system. These tasks include the task of automatically returning the UAV in case of loss of communication with the operator, the solution of which increases the reliability of the navigation system. The change in the nature of the operator's activity, who now does not directly control the movements of the UAV, leads to a change in the nature of the control system. One of the ways to solve this problem is to use an optical navigation system. The analysis of methods and algorithms for optical navigation of an unmanned aerial vehicle: algorithms for local navigation and cartography, correlation-extreme navigation methods and methods of visual odometry. The advantages and disadvantages of optical navigation methods are considered. The use of visual odometry methods has advantages over other methods, but it also has disadvantages associated with the accumulation of errors in the course of the method. Variations of algorithms for simultaneous localization and mapping (SLAM) based on the use of cameras are called visual SLAM. The visual SLAM and visual odometry methods are analyzed. Hybrid SLAM methods solve the problem of error accumulation.The use of UAVs for studying geological processes of the coastline of reservoirs and seas is analyzed. The advantages of using SLAM algorithms for monitoring the state of the coastline are considered. It is concluded that the use of SLAM algorithms for assessing the density of the erosion network of the coastline of reservoirs and seas makes it possible to obtain images without geometric distortions, an optical navigation system based on these algorithms greatly facilitates the operator's task, and will allow the UAV to be returned in case of loss of communication with the operator.

A method for controlling groups of unmanned aerial vehicles in a virtual environment using haptic gloves

The development of control of unmanned aerial vehicles (UAVs) is caused by the lack of developments that allow you to perform a fully autonomous flight to the target position with automatic bypass of static and dynamic obstacles. To ensure the correct execution of the flight task, many methods and algorithms have been developed, however, almost all of them are designed only for performing the UAV flight task in manual or semi-automatic mode. However, there are no widely available developments that allow you to perform a fully autonomous flight. Also, existing UAV control systems have low interactivity, due to the fact that the operator uses a two-dimensional map to control the UAV and also most often one joystick to control one UAV. Based on this, the purpose of this work is to increase interactivity and visibility in the management of UAV groups by developing a system for forming a flight task and control in a virtual environment using haptic gloves. The creation of a system for forming a flight task and managing groups of UAVs will allow the use of UAVs in various areas of human activity, including in conditions that are dangerous to human health and life. The description is presented, both mathematical and software. The advantages, disadvantages and limitations of the proposed method are analyzed.

Simulation of platform-free inertial navigation system of unmanned aerial vehicles based on neural network algorithms

The object of research is the process of controlling the trajectory of unmanned aerial vehicles (UAVs) in autonomous flight mode based on neural network algorithms. The study is based on the application of numerical-analytical approach to the selection of modern technical solutions for the construction of standard models of platformless inertial navigation systems (BINS) for micro and small UAVs, followed by support for assumptions. The results of simulation in the Matlab environment allowed to simulate the operation of the UAV control system based on MEMS technology (using microelectromechanical systems) and Arduino microcomputers. It was also possible to experimentally determine the nature of the influence of the structure of the selected neural network on the process of formation of navigation data during the disappearance of the GPS signal. Thus, to evaluate the effectiveness of the proposed solutions for the construction of BINS, a comparative analysis of the application of two algorithms ELM (Extreme Learning Machine)-Kalman and WANN (Wavelet Artificial Neural Network)-RNN (Recurrent Neural Network)-Madgwick in the form of two experiments. The purpose of the experiments was to determine: the study of the influence of the number of neurons of the latent level of the neural network on the accuracy of approximation of navigation data; determining the speed of the process of adaptive learning of neural network algorithms BINS UAV. The results of the experiments showed that the application of the algorithm based on ELM-Kalman provides better accuracy of learning the BINS neural network compared to the WANN-RNN-Madgwick algorithm. However, it should be noted that the accuracy of learning improved with the number of neurons in the structure of the latent level <500, which iincreases computational complexity and increases the learning process time. This can complicate the practical implementation using micro- and small UAV equipment. In addition, thanks to the simulation, the result of the study of the application of the proposed neural network algorithms to replace the input data instead of GPS signals to the input BINS, allowed to estimate the positioning error during the disappearance of GPS signals. Also, the application of the WANN-RNN-Madgwick algorithm allows to approximate and extrapolate the input signals of navigation parameters in a dynamic environment, while the process of adaptive learning in real time.

Decentralized sampled-data fuzzy controller design for a VTOL UAV

This study focuses on a sampled-data fuzzy decentralized tracking control problem for a quadrotor unmanned aerial vehicle (UAV) under the variable sampling rate condition. To this end, the overall dynamics of the quadrotor is expressed as a decentralized Takagi–Sugeno (T–S) fuzzy model interconnected with each other. Although the proposed decentralized control technique divides the overall UAV control system into attitude and position subsystems, the stability of the entire control system is guaranteed. Besides, in this paper, the model uncertainty, interconnection, and reference trajectory are considered as disturbances acting on the tracking error. To attenuate these disturbances, a novel sampled-data tracking control design technique is derived based on a linear reference model to be tracked and the time-dependent Lyapunov–Krasovskii functional (LKF). By doing so, both the stability of the tracking error dynamics and the minimization of tracking performance are guaranteed. Also, the proposed tracking control design method is derived as a linear matrix inequality (LMI)-based optimal problem. Finally, a simulation example is provided to demonstrate the effectiveness and feasibility of the proposed design methodology.

UAV Path Planning Based on Multi-Layer Reinforcement Learning Technique

Unmanned aerial vehicles (UAVs) have been widely used in many applications due to its small size, swift mobility and low cost. Therefore, the study of guidance, navigation and control (GNC) system of UAV has becoming a popular research direction. Path planning plays an important role in the GNC system. In this paper, a multi-layer path planning algorithm based on reinforcement learning (RL) technique is proposed. Compared to the classic Q-learning, the proposed multi-layer algorithm has a distinct advantage that it collects both global and local information which greatly improves overall performance. The proposed RL algorithm has two layers, the higher layer deals with the local information, which could be considered as a short-term strategy. The lower layer deals with the global information, which could be considered as a long-term strategy. Both the higher layer and lower layer are working in harmony to plan a collision-free path. B-spline curve approach is applied for on-line path smoothing. Simulation results in different scenarios prove the effectiveness of multi-layer Q-learning algorithm.

The Design of Optimal Lateral Motion Control of an UAV Using the Linear-Quadratic Optimization Method in the Complex Domain

The purpose of the paper is to investigate the approach to the Unmanned Aerial Vehicle (UAV) control system synthesis, based on linear-quadratic optimization methods. The paper considers the challenges of developing an optimal control system for UAV “dry” landing (without landing on a sea surface) on a non-aircraft carrier vessel. The purpose of the control system is to guide the UAV to the centerline of the landing strip. To achieve it, lateral movement commands are sent separately through the yaw control loop. In this case, the decoupling of the roll and yaw control loops is obtained as a result of structuring the control system. In this paper the structuring is carried out by transforming the structural diagrams of the UAV control system where the initial motion model of the UAV is non-linear. As a result, the linearization of this non-linear model is performed first. Then, the linearized model is represented in the complex domain in the form of a structural diagram with the corresponding transfer functions. The design of optimal lateral motion control of the UAV is carried out by using the linear-quadratic optimization method in the complex domain. Optimization is carried out separately for the yaw control loop (inner loop) and the lateral movement control loop (outer loop). A quadratic criterion in the form of restrictions on the control energy is used as an optimization criterion. The authors provide examples of system modeling in the article.

Measuring angular coordinates in Unmanned Aerial Vehicles (UAVs) positioning systems and developing a new phase-metric method for goniometric control of UAVs

For the safe operation of Unmanned Aerial Vehicles (UAVs), an effective Automatic Control System (ACS) is necessary, which for successful operation requires high accuracy of the initial information about the UAV’s position in space. Based on the analysis of the shortcomings of the known orientation systems, a phase-metric method of goniometric (angular) control based on accelerometric and gyroscopic transducers for positioning the UAV is proposed, which has a higher accuracy and a wider range of measurement angles. The conducted study showed that in a wide range of rotation angles from 10 to 90 degrees, the root mean square error (RMS) of the results of calculating the rotation angle using the phase-metric method is 8,78 times less than the RMS of the results of calculating the rotation angle using the arctangent function. Reducing the error determines the effectiveness of the proposed method in UAV control systems.