Automatic Landing Research Articles

Minimizing the number of wireless charging PAD for unmanned aerial vehicle–based wireless rechargeable sensor networks

In wireless rechargeable sensor networks, most researchers address energy scarcity by introducing one or multiple ground mobile vehicles to recharge energy-hungry sensor nodes. The charging efficiency is limited by the moving speed of ground chargers and rough environments, especially in large-scale or challenging scenarios. To address the limitations, researchers consider replacing ground mobile chargers with lightweight unmanned aerial vehicles to support large-scale scenarios because of the unmanned aerial vehicle moving at a higher speed without geographical limitation. Moreover, multiple automatic landing wireless charging PADs are deployed to recharge unmanned aerial vehicles automatically. In this work, we investigate the problem of introducing the minimal number of PADs in unmanned aerial vehicle–based wireless rechargeable sensor networks. We propose a novel PAD deployment scheme named clustering-with-double-constraints and disks-shift-combining that can adapt to arbitrary locations of the base station, arbitrary geographic distributions of sensor nodes, and arbitrary sizes of network areas. In the proposed scheme, we first obtain an initial PAD deployment solution by clustering nodes in geographic locations. Then, we propose a center shift combining algorithm to optimize this solution by shifting the location of PADs and attempting to merge the adjacent PADs. The simulation results show that compared to existing algorithms, our scheme can charge the network with fewer PADs.

Moving path following with integrated direct lift control for carrier landing

This paper addresses the three dimensional moving path following (MPF) problem, where a vehicle is required to follow a path attached to a moving target in three dimensional space. The MPF problem is divided into guidance and attitude control. For guidance, a non-singular three dimensional MPF law is proposed. For attitude control, a novel integrated direct lift control method is demonstrated to response to the guidance commands. The idea of using direct lift improves the control performance of a fixed-wing aircraft. In addition, both of the MPF law and the integrated direct lift control method are utilized to design the flight controller for automatic carrier landing, which is a typical MPF mission. Finally, the theoretical analysis and numerical simulation verify the advantages of the proposed controller.

Flight Testing Automatic Landing Control for Unmanned Aircraft Including Curved Approaches

Automatic landing of aircraft is a challenging guidance and control task that requires multiple feedback loops and a precise sequence of actions. Increasing operational flexibility and reducing the dependence on external infrastructure are key challenges for future unmanned aircraft. Usually, an aircraft performs the final approach on a straight line. This paper contributes a complete automatic landing controller capable of using three-dimensional curved approach paths all the way until touchdown. The controller consists of a nonlinear guidance law that steers the aircraft along a predefined spline path, various single-input–single-output control loops for rate and attitude control, and a robust multivariable flare controller. This flare controller ensures a three-point landing, i.e., simultaneous touchdown of all three wheels. Further, practical issues such as bumpless mode transfer and anti-windup compensation are considered. The controller is evaluated in multiple flight test experiments. Both the crabbed approach and the sideslip technique are demonstrated on several different approach paths, such as a steep curve and a helix. These paths are particularly challenging, because the flare maneuver is performed while the aircraft is in a turn. The controller is shown to reliably land the aircraft on an unpaved runway with high precision.

Virtual prototyping of the lunar module landing system to improve cosmonauts’ spatial and situational awareness

Relevance. The transition to manned flights after the launches of the automatic stations of the «Luna-Globus» series will require studying issues of the crew safety in lunar missions. First of all, it will be necessary to clarify the role and capabilities of cosmonauts when landing the lunar module in complicated conditions. The subject of the study is the means of modeling and visualizing the progress of the flight operation observed by the operator. The area of study is the issues of ensuring the safety of the automatic landing of the lunar descent module with the possibility of switching to manual control mode after a decision was made by a human to change the landing site of the lunar module. The provision of spatial and situational awareness is considered in this context as a prerequisite for the timely response of the operator to the occurrence of a non-standard situation. Objective. The goal of the work is to present the virtual prototyping of the Moon landing stage for studying details of information support for cosmonauts during the conditions of visual control complication. Methodology. The analysis of ways to maintain spatial and situational awareness for a timely assessment by the operator of the suitability of the predicted site in the landing area is a key condition for deciding whether to switch from automatic mode to manual mode. At the same time, the quality of preparation and decision-making in a short time frame significantly depends on the accepted methods of visualizing the landing on the surface of the Moon. Results and Discussion. The directions of application of modeling and visualization tools for virtual prototyping of the landing of the descent lunar module are formulated. It is shown that a person's decision-making in conditions of time scarcity and possible visual interference when monitoring the external environment requires special means of information support. The issues of organizing the visual environment in accordance with the information needs of a person are studied taking into account the prototypes in the classes of manned and unmanned vertical take-off and landing vehicles, for which similar types of operator activities are described. This made it possible to formulate basic approaches to modeling the landing of vehicles in conditions of problems with visual perceptions. Taking into account the increased requirements, we consider promising approaches based on the synthesis of 2D and 3D-visual dynamic scenes, as well as precedents for the use of synthetic vision systems in the described conditions. The scope of application of the obtained results is not limited to the tasks of designing complex human-technical systems, but may have applications in the field of building computer simulators for the training of cosmonauts. This practice compares favorably with the options for human training on hardware-in-the-loop simulation models and on real helicopter-type vehicles in terms of safety and flexibility of modification. Conclusion. The use of virtual prototyping of the moon landing makes it possible to expand the search for options for improving the cosmonaut's spatial and situational awareness. The general conclusion in the context of this goal pursuing is the feasibility of using simulation methods to build a virtual environment that recreates the conditions for a cosmonaut to make a decision in an emergency situation when landing a lunar module, as one of the most critical flight operations for the safety of lunar missions. Key words Lunar exploration, lunar lander, landing simulation and visualization, virtual activity environment, unmanned and manned vertical take-off and landing vehicles, spatial and situational awareness, synthetic vision systems.

Model Predictive Control for Automatic Carrier Landing with Time Delay

This paper focuses on the problem of automatic carrier landing control with time delay, and an antidelay model predictive control (AD-MPC) scheme for carrier landing based on the symplectic pseudospectral (SP) method and a prediction error method with particle swarm optimization (PE-PSO) is designed. Firstly, the mathematical model for carrier landing control with time delay is given, and based on the Padé approximation (PA) principle, the model with time delay is transformed into an equivalent nondelay one. Furthermore, a guidance trajectory based on the predicted trajectory shape and position deviation is designed in the MPC framework to eliminate the influence of carrier deck motion and real-time error. At the same time, a rolling optimal control block is designed based on the SP algorithm, in which the steady-state carrier air wake compensation is introduced to suppress the interference of the air wake. On this basis, the PE-PSO delay estimation algorithm is proposed to estimate the unknown delay parameter in the equivalent control model. The simulation results show that the delay estimation error of the PE-PSO algorithm is smaller than 2 ms, and the AD-MPC algorithm proposed in this paper can limit the landing height error within ±0.14 m under the condition of multiple disturbances and system input delay. The control accuracy of AD-MPC is much higher than that of the traditional pole assignment algorithm, and its computational efficiency meets the requirement of real-time online tracking.

Impact of actuators backlash on the helicopter control during landing on the moving vessel deck

PurposeThe purpose of this paper is to test the performance of the control system developed for the helicopter automatic approach and landing on the moving vessel deck, when different values of backlashes are applied to the four control actuators.Design/methodology/approachThe system consists of automatic control algorithm based on the linear quadratic regulator and the vessel motion prediction algorithm based on autoregressive method with parameters calculated using Burg’s method. Necessary navigation data is provided by on-board inertial navigation system/Global Positioning System. Calculated control commands are executed by four electromechanical actuators. Performance of the mission, which is based on selected procedure of approach and landing of the helicopter on the moving vessel deck, is analyzed taking into account different values of backlashes applied to the actuators.FindingsIn this paper, a description of the control system dedicated for automatic approach and landing of the helicopter on the moving vessel deck is shown. Necessary information about helicopter dynamic model, control system and vessel motion model is included. Tests showing influence of actuator backlashes on the mission performance are presented.Practical implicationsThe developed control methodology can be adapted for selected helicopter and used in prospective development of an automatic flight control system (AFCS) or in a simulator. The system can be used to define in which conditions helicopter can perform safe and successful automatic approach and landing on a moving vessel deck.Originality/valueIn this paper, an integrated control system is presented; influence of the control actuator backlashes on the mission performance is analyzed.

Fixed Wing Aircraft Automatic Landing with the Use of a Dedicated Ground Sign System

The paper presents automatic control of an aircraft in the longitudinal channel during automatic landing. There are two crucial components of the system presented in the paper: a vision system and an automatic landing system. The vision system processes pictures of dedicated on-ground signs which appear to an on-board video camera to determine a glide path. Image processing algorithms used by the system were implemented into an embedded system and tested under laboratory conditions according to the hardware-in-the-loop method. An output from the vision system was used as one of the input signals to an automatic landing system. The major components are control algorithms based on the fuzzy logic expert system. They were created to imitate pilot actions while landing the aircraft. Both systems were connected with one another for cooperation and to control an aircraft model in a simulation environment. Selected results of tests presenting control efficiency and precision are shown in the final section of the paper.

Benefits for Greek Regional Airports Through Innovative Approach Technology Using an LPV to GLS Converter: A Case Study for Corfu and Thessaloniki

Required navigation performance procedures are a cost-effective and accurate solution for aircraft instrument approaches, especially when combined with a final approach segment utilizing satellite based augmentation. However, transport category aircraft are currently not equipped with the satellite based augmentation for precision guidance. An existing converter technology can provide this final approach segment to aircraft equipped with the GPS landing system. Then, as an added bonus, an automatic landing at pilots discretion is possible after the presented approach. Here, we study Thessaloniki and Corfu airports, both accommodating a large number of transport category aircraft, with many ground infrastructure constraints. Both were recently equipped by the Hellenic air navigation service provider with RNP approaches. We successfully flight tested the satellite based augmentation to GPS landing system converter and show that both airports could benefit from a permanent installation of such a system by having fewer diversions.

Control of Autonomous Landing of UAV of Airplane-Type on the Static and Dynamic Sites with Using of "Flexible" Kinematic Trajectories

The final and one of the most important stages of the aircraft-type unmanned aerial vehicles (UAV) flight is landing. In this regard the problem of automating the control by UAV landing in difficult meteorological conditions is becoming increasingly urgent. In some cases for refueling and recharging UAVs it is advisable to use the dynamic mobile landing site (MLS) instead of the traditional stationary landing site (SLS). In the present paper we consider the setting of and solution of the control problem by the terminal landing maneuver of a UAV. It provides its transfer from the current initial state to the target final state along " flexible" kinematic trajectories both on the SLS and on the MLS. To solve the problem of automatic landing of UAV on SLS or MLS the mathematical model of the dynamics of its movement was developed. It’s based on the concept of " flexible" kinematic trajectories with spatial synchronization of controlled movements. The control algorithm by the terminal vertical landing maneuver of UAV on SLS by the method of dynamics inverse problem using the principle of " flexible" kinematic trajectories is developed. And also the control algorithm by the terminal landing maneuver of UAV on MLS by the method of dynamics inverse problems using the principles of " flexible" kinematic trajectories and aiming into the target point was also developed. Computer approbation of the synthesized control algorithms for the landing maneuver of UAV "Aerosonde" under conditions of various wind disturbances was carried out using digital modeling in the Matlab environment.

Automatic Landing System with Consideration of Constraints Using Dynamic Window Approach

Automatic Landing System with Consideration of Constraints Using Dynamic Window Approach

Algorithm for determining the angular position of the ship’s deck from an unmanned aircraft using digital image processing

Problem statement. An unmanned vertical take-off and landing aircraft equipped with means for analyzing parameters of a certain pattern is usually not able to land on a landing site that is not equipped with the appropriate markings. To solve this problem, it is possible to install onboard the UMA means for generating a special test image that is projected from the aircraft to the intended landing site, and means for automatically measuring and analyzing the parameters of this image.Objective. Develop an algorithm for applying digital image processing to determine the angular position of the ship’s deck or any other flat landing ground from an unmanned aircraft with vertical take-off and landing. The article presents the calculated relations that allow calculating the angular position and evaluating the general condition of the landing ground using a 3D model of its surface.Results. An algorithm has been developed according to which a particular test image is generated by a group of laser emitters on the landing site. Digital image processing methods are used to analyze the test image to assess the condition and determine the inclination angles of the landing site.Practical implications. The test results of the considered algorithm showed the possibility of its application in the system of automatic landing of an unmanned aircraft with vertical take-off and landing.

Fixed-time control for automatic carrier landing with disturbance

This paper addresses the fixed-time control problem for automatic carrier landing. By transforming a six-degrees-of-freedom fixed-wing aircraft model into the affine form with angle of attack controlled by thrust independently, backstepping technique is able to be adopted as the main control frame. Subsequently, for the purpose of improving convergent performance and success rate for carrier landing, fixed-time control method for a high-order multivariable system is proposed, and it is applied to the automatic carrier landing control system. In order to realize complete fixed-time convergence performance for the closed-loop system, fixed-time disturbance observers are employed in the control structure to efficiently estimate the external disturbances. Moreover, nonlinear fixed-time filters are incorporated to avoid tedious derivative calculation without affecting the fixed-time convergence performance of the system. Finally, the comparative simulation results with other methods demonstrate the effectiveness and superiority of proposed fixed-time control scheme.

Lidar-aided Autonomous Landing and Vision-based Taxiing for Fixed-Wing UAV

Autonomous UAV technology is limited in its ability to land safely at distinct airfields that have not been precisely surveyed and where GPS is unavailable. In this paper, we present a multi-sensor system for the automatic landing of fixed-wing UAV. The system is composed of a high precision aircraft controller, a range finder (Lidar) and a vision module used for detection and tracking of runways. The estimation of the position of the fixed-wing UAV is by using Lidar and performs gliding till flaring. Then, a federated extended Kalman filter (EKF) structure is costumed and utilizes the solutions of the IMU, GPS and Lidar as independent measurements to estimate the position of the vehicle. The framework can be used to integrate the vision solutions and enables the estimation to be smooth and robust landing. For taxiing, the neural network is used such that from live video stream from the camera trains the UAV to land precisely along the runway.

Design of an Executable ANFIS-based Control System to Improve the Attitude and Altitude Performances of a Quadcopter Drone

Nowadays, quadcopters are presented in many life applications which require the performance of automatic takeoff, trajectory tracking, and automatic landing. Thus, researchers are aiming to enhance the performance of these vehicles through low-cost sensing solutions and the design of executable and robust control techniques. Due to high nonlinearities, strong couplings and under-actuation, the control design process of a quadcopter is a rather challenging task. Therefore, the main objective of this work is demonstrated through two main aspects. The first is the design of an adaptive neuro-fuzzy inference system (ANFIS) controller to develop the attitude and altitude of a quadcopter. The second is to create a systematic framework for implementing flight controllers in embedded systems. A suitable model of the quadcopter is also developed by taking into account aerodynamics effects. To show the effectiveness of the ANFIS approach, the performance of a well-trained ANFIS controller is compared to a classical proportional-derivative (PD) controller and a properly tuned fuzzy logic controller. The controllers are compared and tested under several different flight conditions including the capability to reject external disturbances. In the first stage, performance evaluation takes place in a nonlinear simulation environment. Then, the ANFIS-based controllers alongside attitude and position estimators, and precision landing algorithms are implemented for executions in a real-time autopilot. In precision landing systems, an IR-camera is used to detect an IR-beacon on the ground for precise positioning. Several flight tests of a quadcopter are conducted for results validation. Both simulations and experiments demonstrated superior results for quadcopter stability in different flight scenarios.

회전익 드론 접촉식 충전스테이션 도킹을 위한 딥러닝 기반 자동착륙시스템 구현

회전익 드론 접촉식 충전스테이션 도킹을 위한 딥러닝 기반 자동착륙시스템 구현

İnsansız Hava Araçları İçin Görüntü İşleme Tabanlı Otonom İniş

Günümüzde teknolojik anlamda herkes güvenli ölçümlerin hayatımızdaki etkisine oldukça aşinadır. Yani bu bağlamda araştırmacılar tarafından güvenli ölçüm çalışmaları için birçok çalışma yapıldı ve bunlardan biri İnsansız Hava Aracı. İnsansız Hava Aracının iyi bilinen bir kullanımı, belki de, bu cihazı sadece insansız hareketi için değil, aynı zamanda keyfi alanlar üzerinde uçuş sırasında benzersiz manevra için son derece pratik kılan güvenlik ve bakım ölçümlerindeki kabiliyetidir. Bu araştırmada İnsansız Hava Aracının otomatik inişi ele alınmıştır. İnsansız Hava Araçlarının (İHA) günümüzde gözetleme, keşif, askeri amaçlar, taşımacılık, zirai ilaçlama, kamera çekimi, yangın söndürme gibi birçok alanda kullanımı hızla artmıştır. İHA sistemlerinde kalkış, seyir, güdüm ve iniş kontrolü en önemli olaylardır. İHA’nın seyir halinde havadaki dengesi, çevre güvenliği ve uçuş stabilitesi açısından önem arz etmektedir. İHA’nın kalkış ve iniş manevraları güvenlik ve kararlılık açısından oldukça önemlidir. Bu çalışmada, havadaki bir İHA’nın görüntü işleme metodları kullanılarak zemin üzerindeki renkli bir alana otonom olarak inmesi sağlanmıştır. Alan üzerine dairesel biçimde bir cisim konulmuştur. Bunun için renkli dairesel cismin kamera ile koordinatları ölçülerek bu koordinatlara göre iniş yörüngesi belirlenmiştir. Kamera ile çekilen görüntü 512 piksele ayrılmıştır. Çekilen görüntünün tam orta noktası 256x256 pikseller olarak ayarlanmıştır. Kameradan gelen anlık geri kazançlar ile İHA kendi konumunu sürekli kontrol ederek sabit kalmaya çalışmıştır. Bu sayede otonom iniş için gerekli olan anlık kontrol edilen değerler kamera görüntüsü kullanılarak değerlendirilmiştir. Ayrıca çalışmada İHA için eşdeğer lineer bir transfer fonksiyonu elde edilmiştir. İHA’nın giriş sinyallerinin ve çıkış sinyallerinin değerleri incelenerek System identification ile uygun bir transfer fonksiyonu elde edilmiştir. Bu transfer fonksiyonu denetleyici tasarımında kullanılmıştır.

Adaptive fault-tolerant control for carrier-based UAV with actuator failures

An adaptive fault-tolerant control (AFTC)1 method is developed for an automatic carrier landing system (ACLS)2 with actuator failures. First, an actuator fault model is added to the linear unmanned aerial vehicle (UAV)3 model. Then, an AFTC algorithm based on the output feedback designs for output tracking is raised to solve the theoretical problem extracted through the practical automatic carrier landing process. The σ-modification based robust adaptive update law is used for both parameterized and unparameterized fault. Then the stability of the system is verified by Lyapunov function method. Finally, the ACLS simulation is conducted, which includes the guidance law designed by PID method, the flight controller designed by the proposed AFTC method and a deck motion prediction and compensation based on auto-regression (AR)4 model. The comparison result shows that the improved robust AFTC can effectively deal with both parameterized and unparameterized fault, as well as external disturbances.

An Embedded Platform for Positioning and Obstacle Detection for Small Unmanned Aerial Vehicles

Unmanned Aerial Vehicles (UAV) with on-board augmentation systems (UAS, Unmanned Aircraft System) have penetrated into civil and general-purpose applications, due to advances in battery technology, control components, avionics and rapidly falling prices. This paper describes the conceptual design and the validation campaigns performed for an embedded precision Positioning, field mapping, Obstacle Detection and Avoiding (PODA) platform, which uses commercial-off-the-shelf sensors, i.e., a 10-Degrees-of-Freedom Inertial Measurement Unit (10-DoF IMU) and a Light Detection and Ranging (LiDAR), managed by an Arduino Mega 2560 microcontroller with Wi-Fi capabilities. The PODA system, designed and tested for a commercial small quadcopter (Parrot Drones SAS Ar.Drone 2.0, Paris, France), estimates position, attitude and distance of the rotorcraft from an obstacle or a landing area, sending data to a PC-based ground station. The main design issues are presented, such as the necessary corrections of the IMU data (i.e., biases and measurement noise), and Kalman filtering techniques for attitude estimation, data fusion and position estimation from accelerometer data. The real-time multiple-sensor optimal state estimation algorithm, developed for the PODA platform and implemented on the Arduino, has been tested in typical aerospace application scenarios, such as General Visual Inspection (GVI), automatic landing and obstacle detection. Experimental results and simulations of various missions show the effectiveness of the approach.

Bistatic-Range-Doppler-Aperture Wavenumber Algorithm for Forward-Looking Spotlight SAR With Stationary Transmitter and Maneuvering Receiver

Bistatic forward-looking spotlight synthetic aperture radar with stationary transmitter and maneuvering receiver (STMR-BFSSAR) is a promising sensor for various applications, such as the automatic navigation and landing of maneuvering vehicles. Because of the bistatic forward-looking configuration and the receiver’s maneuvers, conventional image formation algorithms suffer from high computational complexity or small size of a well-focused scene if applied to STMR-BFSSAR. In this article, we propose a wavenumber-domain algorithm for STMR-BFSSAR image formation, which is termed the bistatic-range-Doppler-aperture wavenumber algorithm (BDWA). First, a novel range model in bistatic-range and Doppler-aperture coordinate space instead of conventional Cartesian coordinate space is established by employing the elliptic polar coordinate system and the method of series reversion. The novel range model not only makes the echo’s samples to be regular along the direction of the bistatic-range wavenumber axis but also constructs a curved wavefront close to the true wavefront. Second, an operation termed wavenumber-domain gridding is conceived to regularize the echo’s samples along the Doppler-aperture wavenumber axis, which can be implemented by 1-D interpolation. The proposed algorithm significantly outperforms the conventional algorithms in terms of computational complexity and scene size limits. Both point and distributed targets are simulated for two STMR-BFSSAR systems with different parameters. The simulation results verify the validity and superiority of the proposed BDWA.

UAV Positioning Mechanisms in Landing Stations: Classification and Engineering Design Review.

Landing platforms’ automation is aimed at servicing vertical take-off and landing UAVs between flights and maintaining their airworthiness. Over the last few years, different designs for the landing platforms have been proposed. This shows a strong development and establishment of automatic landing platforms with UAV positioning devices on the landing site. Positioning and safe fixation of the UAV are some of the main features of the landing platform, especially if it is mounted on a movable vehicle. This article focuses exclusively on the landing platform and its elements that provide the positioning of the UAV by affecting it during and after the landing. Both active devices and mechanisms and passive elements used for positioning are considered. This article, based on the review of recent patents and publications, gives the classification of positioning approaches used in landing stations with the analysis of the required landing precision, as well as the pros and cons of each type of approach.