Automatic Landing Control Research Articles

Inertial Navigation Position and Orientation Estimation with Occasional Galileo Satellite Position Fixes and Stereo Camera Measurements

Abstract In this paper an adaptive unscented Kalman filter based mixing filter is used to integrate kinematic satellite aided inertial navigation system with vision based measurements of five representative points on a runway in a modern receiver that incorporates carrier phase smoothing and ambiguity resolution. Using high resolution multiple stereo camera based measurements of five points on the runway, in addition to a set of typical pseudo-range estimates that can be obtained from a satellite navigation system such GPS or GNSS equipped with a carrier phase receiver, the feasibility of generating high precision estimates of the typical outputs from an inertial navigation system is demonstrated. The methodology may be developed as a stand-alone system or employed in conjunction with a traditional strapped down inertial navigation systems for purposes of initial alignment. Moreover the feasibility of employing adaptive mixing was explored as it facilitates the possibility of using the system for developing a vision based automatic landing controller.

Special Section on Intelligent Unmanned Systems

There has been increased worldwide interest in the research on intelligent unmanned systems in recent decades. The unmannedsystem technologies have been implemented in the underwater, ground, aerial, and space domains within an ever-extending operational envelope. The miniaturization of the hardware footprint coupled with exponentially increased computing power has enabled more efficient application of a wide range of unmanned vehicles. The papers in this special section represent recent contributions to several aspects of intelligent unmanned systems. The papers were largely an extension of select papers presented at the ICIUS2010 held in Bali, Indonesia, in October 2010. Three papers deal with the development of intelligent algorithms for unmanned aerial vehicles, while two papers focus on the software and hardware integration. The rest of the papers cover the application of aerospace technology for unmanned-vehicle design. The paper by Manathara and Ghose addresses the problem of multiple unmanned aerial vehicle (UAV) rendezvous when the UAVs have to perform maneuvers to avoid collisions with other UAVs. The authors proposed a solution that consists of velocity control and a wandering maneuver of the UAVs based on a consensus among them on the estimated time of arrival at the point of rendezvous. This simple algorithm was shown to be useful in tracking stationary or slowly moving targets with a standoff distance. Kim et al. paper present an automatic landing control design using adaptive, integrated guidance and control (IGC) logic. The proposed IGC design uses a combination of an adaptive output feedback inversion and backstepping techniques. The authors formulated the problem as an adaptive output feedback control problem for a line-of-sight–based chasing-flight configuration. The automatic landing system using IGC logic was evaluated using a sophisticated six-degrees-of-freedom nonlinear simulation program with the approach and landing scenario. Jeong et al. focused on the design of a robust H-infinity attitude controller for an unmanned small-scale helicopter. It was demonstrated that the H-infinity controller works amiably when applied to the nonlinear model, even though it is designed using a linear model approximation. The time-domain simulation with the nonlinear model demonstrated that the proposed controller was very robust to the uncertainties as expected, overcoming large gain uncertainties and time delay in each input channel. Formal verification currently plays an important role in guaranteeing the correctness of the operation of safety-critical systems, for example, in UAVs. Lee et al. discuss formal modeling and verification of operational flight programs (OFPs) in a small-scale unmanned helicopter. Two different formal models for the OFP were developed and verified using SPIN and UPPAAL model checkers. Real-time behavior of theOFPwas specified using a timed-automata model. Their verification of the OFP found several safety-critical faults to be reported to and fixed by the development team. One of the key features of autonomous flight of UAVs is the ability to perform localization and map building of flight environments simultaneously. Park et al. present vision-based simultaneous localization and mapping (SLAM) for small UAVs in global-positioningsystem–denied environments. A method that combines onboard and on-ground localization and mapping was proposed. The paper by Thu et al. investigates the nature of vortex structure developed by a double-delta wing. Dye-flow visualization in a small-scale water tunnel was used for the study. The authors identified two types of flow interaction, which are enveloping and coiling-up modes. Characteristics of the two modes were examined for various angles of attack (AOAs) at relatively low Reynolds numbers of 10,000 and 15,000. The authors found that the wing vortex became stronger and the enveloping mode was dominant for a low AOA, while the coiling-up mode was dominant at a high AOA. They also reported that the transition of these two modes occurred at around an AOA of 20 . Another paper in the special section studied the unsteady flow field of a flapping model butterfly under the zero-advance ratio (J 5 0) condition using timeresolved stereoscopic particle image velocimetry. The effect of feathering on thrust generation because of chordwise wing flexibility was identified by focusing on the ejection of airflow from the gap between two wings. Ghosh et al. found that the wing flexibility adds a feathering effect and enhances net lift and thrust generation through ejection of vortex pairs during the downstroke-to-upstroke–motion reversal. They also reported that the thrust produced was positive all over the cycle, even at J 5 0, because of the feathering motion. The special section editors would like to express their sincerest gratitude to all the contributing authors. We hope that the readers will find the content of this section not only relevant but also stimulating and beneficial for their ongoing research endeavors.

Automatic landing control plane based on the predictive model algorithm

Automatic landing control plane based on the predictive model algorithm

Automatic Landing Control Using Adaptive Self-Organizing Cerebellar Model Articulation Controller

Automatic Landing Control Using Adaptive Self-Organizing Cerebellar Model Articulation Controller

Non-linear position control for hover and automatic landing of unmanned aerial vehicles

This study presents a disturbance attenuation controller for horizontal position stabilisation for hover and automatic landings of a rotary-wing unmanned aerial vehicle (RUAV) operating close to the landing deck in rough seas. Based on a helicopter model representing aerodynamics during the landing phase, a non-linear state feedback ℋ∞ controller is designed to achieve rapid horizontal position tracking in a gusty environment. Practical constraints including flapping dynamics, servo dynamics and time lag effect are considered. A high-fidelity closed-loop simulation using parameters of the Vario XLC gas-turbine helicopter verifies performance of the proposed horizontal position controller. The proposed controller not only increases the disturbance attenuation capability of the RUAV, but also enables rapid position response when gusts occur. Comparative studies show that the ℋ∞ controller exhibits performance improvement and can be applied to ship/RUAV landing systems.

CAT III Autoland Control Laws Design Based on Multi-Objective Optimization

The CAT III longitudinal automatic landing control laws based on multi-objective optimization is discussed. Firstly summarized the CAT III airworthiness criteria and transformed into the specifications of control system. The configuration of the longitudinal automatic landing controllers is proposed secondly and multi-objective optimization is used to tradeoff free parameters of the controllers. The Monte Carlo simulation results show the designed control laws fulfill the CAT III requirements, when there are uncertainties of structure, measurement error and disturbances.

Adaptive Integrated Guidance and Control Design for Automatic Landing of a Fixed Wing Unmanned Aerial Vehicle

This paper presents an automatic landing control design using adaptive, integrated guidance and control (IGC) logic. The proposed IGC design uses a combination of an adaptive output feedback inversion and backstepping techniques. The problem is formulated as an adaptive output feedback control problem for a line-of-sight-based chasing flight configuration. The design objective is to regulate the relative distance between the aircraft and the moving reference point on a landing pattern and two bearing angles maintaining turn coordination. Adaptive neural networks are trained online with available measurements to compensate for inversion error as a result of unmodeled dynamics and modeling errors of the aircraft in the design process. In addition, a reference command trajectory for the automatic landing control is designed in a way that the aircraft follows the landing pattern regardless of its initial position. The automatic landing system using IGC logic is evaluated using a sophisticated six-degrees-of-freedom nonlinear simulation program with the approach and landing scenario.

Automatic Landing Control System Design Using Adaptive Neural Network and Its Hardware Realization

This paper presents an adaptive neural network, designed to improve the performance of conventional automatic landing systems (ALS). Real-time learning was applied to train the neural network using the gradient-descent of an error function to adaptively update weights. Adaptive learning rates were obtained through the analysis of Lyapunov stability to guarantee the convergence of learning. In addition, we applied a DSP controller using the VisSim/TI C2000 Rapid Prototyper to develop an embedded control system and establish on-line real-time control. Simulations show that the proposed control scheme has superior performance to conventional ALS under conditions of wind disturbance of up to 75 ft/s.

Automatic Landing Control of Outdoor Blimp Robots

A surveillance system is required to gather the suffering information in the stricken area safely after large-scale disasters. An autonomous blimp is the best option for this purpose. This paper proposes a control design method for automatic landing of outdoor blimp robots. The landing method consists of stabilizing control in horizontal plane and longitudinal control for letdown-velocity and pitching motion of the blimp. The states of the kinematic model are transformed to design a time-varying stabilizing controller in horizontal plane to constrain the blimp motion. Some simulations and experiments are performed to confirm the usefulness of the proposed method by using an outdoor blimp whose length is 12m.

Analysis and comparison of aircraft landing control using recurrent neural networks and genetic algorithms approaches

This paper presents an intelligent aircraft automatic landing controller that uses recurrent neural networks (RNN) with genetic algorithms (GAs) to improve the performance of conventional automatic landing system (ALS) and guide the aircraft to a safe landing. Real-time recurrent learning (RTRL) is applied to train the RNN that uses gradient-descent of the error function with respect to the weights to perform the weights updates. Convergence analysis of system error is provided. The control scheme utilizes five crossover methods of GAs to search optimal control parameters. Simulations show that the proposed intelligent controller has better performance than the conventional controller.

Aircraft Landing Control Based on CMAC and GA Techniques

This paper presents an intelligent control scheme that uses a cerebellar model articulation controller (CMAC) and genetic algorithms (GA) in aircraft automatic landing control and to make automatic landing systems (ALS) more intelligent. The proposed intelligent controller can act as an experienced pilot and guide the aircraft to a safe landing in severe turbulence environment. Current flight control law is adopted in the intelligent design. Tracking performance and adaptive capability are demonstrated through software simulation.

Digital Autoland Control Laws Using Quantitative Feedback Theory and Direct Digital Design

of several aircraft problems, but not for outer-loop control or for automatic landing. This paper describes the synthesis and development of an automatic landing controller for medium-sized unmanned aerial vehicles, using discrete quantitative feedback theory. Controllers for the localizer, glideslope tracker, and automatic flare are developed, with a focus on outer-loop synthesis and robustness with respect to model uncertainty. Linear, nonreal-time, six-degree-of-freedom Monte Carlo simulation is used to compare the quantitative feedback theory controller with a baseline proportional–integral controller in several still-air and turbulent-air landing scenarios. Results presented in the paper show that the quantitative feedback theory controller provides superior performance robustness to the proportional–integral controller in turbulent-air conditions when model uncertainties are present. It is therefore concluded to be a promising candidate for an autoland controller for unmanned air vehicles.

Application of Neural Networks to Disturbances Encountered Landing Control

Neural network applications to aircraft automatic landing control are presented. Conventional automatic landing systems (ALSs) can provide a smooth landing, which is essential to the comfort of passengers. However, these systems work only within a specified operational safety envelope. When the conditions are beyond the envelope, such as turbulence or wind shear, they often cannot be used. The objective of this paper is to investigate the use of neural networks in ALSs and to make these systems more intelligent. Current flight control law is adopted in the intelligent controller design. Tracking performance and robustness are demonstrated through software simulations. This paper presents five different neural network controllers to improve the performance of conventional ALSs based on a modified learning-through-time process. Simulation results show that the neural network controllers can successfully expand the safety envelope to include more hostile environments such as severe turbulence

Fault-Tolerant Robust Automatic Landing Control Design

A new approach is presented for developing reliable automatic landing controllers that can tolerate actuator stuck faults. The approach is based on the solvability of linear matrix inequalities and polytopic fault models. The H 2 control technique is used to guarantee tracking performance with respect to a given glide slope trajectory. A high-fidelity fighter aircraft model is studied to illustrate the proposed approach. The six-degree-of-freedom nonlinear aircraft model with independent left and right control surfaces is established using the appropriate aerodynamic data from wind-tunnel test and computational fluid dynamics. A single fixed reliable automatic landing controller is designed for the whole landing process. It achieves optimized tracking performance in normal operation and maintains an acceptable level of tracking performance in the case of single contingency actuator stuck fault among the left and right ailerons and horizontal stabilators. Nonlinear simulation under various faults, measurement noises, and wind disturbances such as deterministic wind, wind turbulence, and wind shear are included in this study. Simulation results show that such a reliable controller design approach can achieve zero steady-state tracking error, good tracking response, robustness against wind disturbances, and reliability against actuator stuck faults.

Longitudinal Automatic Landing in AdaptivePID Control Law Under Wind Shear Turbulence

This paper deals with a problem of automatic landing guidance and control ofthe longitudinal airplane motion under the wind shear turbulence. Adaptive gainscheduled PID control law is proposed in this paper. Fuzzy logic is the main part ofthe adaptive PID controller as gain scheduler. To illustrate the successful applicationof the proposed control law to the automatic landing control problem, numericalsimulation is carried out based on the longitudinal nonlinear airplane model excited bythe wind shear turbulence. The simulation results show that the automatic landingmaneuver is successfully achieved with the satisfactory performance and the gainadaptation of the control law is made adequately within the limited gains.

122 自律型小型無人ヘリコプターの高度制御と自動離着陸制御

122 自律型小型無人ヘリコプターの高度制御と自動離着陸制御

1304 自動運転トランスファクレーン

This paper describes a new automatic operation system suitable for RTG (Rubber Tired Gantry Crane) used in container yards. It has been very difficult to realize automated RTG, because RTG is mounted on rubber tires that rigidity is low. We developed new technologies to realize automated RTG. (1) Image sensors installed at corners of spreader to detect accurate container position directly (2) Automatic landing control (3) Automatic gantry travel and positioning control

Automatic Landing System Design Using Fuzzy Logic

A fuzzy logic system is developed for automatic landing control of a transport aircraft. A linear longitudinal aircraft model, with landing gear and flaps deployed at the sea level, is employed for fuzzy logic controller design of automatic landing system including the two landing phases - the glide-path capture and the flare maneuver. In addition, the fuzzy control system is tested using different values of fuzzy controller scaling factors on a six degree of. freedom nonlinear aircraft model. It is shown that the simple tuning fuzzy controller with altered scaling factors is well suited for controlling the trajectory of the aircraft in the landing phase which requires simultaneous control of engine thrust for the velocity and elevator for the pitch attitude in order to change altitude with a constant airspeed.

Design of Automatic Landing Systems Using Mixed H/H Control

Mixed H2/HX control technique is employed to develop controllers for auto-landing systems for a commercial airplane. A linear model of the aircraft in longitudinal motion is established using the appropriate aerodynamic coefficients. With the control actuator, tracking errors, and altitude motion, the aircraft is shown to be governed by an augmentation system along with its filter model. Two kinds of optimal and robust control requirements are designed, which need to be satisfied simultaneously. One of requirements is with respect to an optimal trajectory selection for landing routes. The H2 method is used to minimize a cost function such that the optimal gain for trajectory optimization can be obtained. The other requirement is with respect to the disturbance attenuation. The Hm technique is employed to obtain the necessary formulation for the robust control gain to minimize the affection of the disturbance to the performance output. An algorithm is developed based on the convex theory for the mixed H2I Hn control and filter gains, which provides a suboptimal solution. A large commercial aircraft (Boeing 747-200) is employed to illustrate the potential of the proposed method. It is shown that the glide slope capture motion and flare maneuver of the aircraft are accomplished quite well, and the amplitudes of all maneuver are within FAA requirements. L INTRODUCTION Control of aircraft under difficult maneuvers is a problem of both theoretical and practical interest. Control under one of these difficult maneuvers, that of landing, is discussed and addressed in this paper. Design of automatic landing systems has been achieved using both robust and optimal control methods [1-3]. Reference [1] employed the #„ synthesis to design an automatic landing controller for an F-14 aircraft. Design of landing systems encountering windshear is given in

Wind Modeling and Lateral Control for Automatic Landing

For the purposes of aircraft control system design and analysis, the wind can be characterized by a mean com- ponent which varies with height and by turbulent components which are described by the von Karman correlation model. The aircraft aerodynamic forces and moments depend linearly on uniform and gradient gust components obtained by averaging over the aircraft's length and span. The correlations of the averaged com- ponents are then approximated by the outputs of linear shaping filters forced by white noise. The resulting model of the crosswind shear and turbulence effects is used in the design of a lateral control system for the automatic landing of a DC-8 aircraft. NE of the more challenging problems facing an autopilot designer is the synthesis of feedback logic which will achieve the desired attitude and position of an aircraft at touchdown in the presence of turbulent crosswinds. During the approach phase of an automatic landing, the desired flight path is maintained by heading slightly into the prevailing crosswind (crabbing). However, at touchdown, the aircraft centerline must be aligned with the runway to prevent lateral skidding of the wheels on the landing gear. The transition from the approach attitude to the touchdown attitude, termed the maneuver, is usually carried out by the pilot, using the rudder to reduce the heading deviation, and ailerons to dip the windward wing tip sightly so as to maintain the lateral position in the presence of the resulting aerodynamic sideslip. When visibility is reduced to the point where the pilot cannot maintain the required visual reference, it is desirable to perform the decrab maneuver automatically. In order to carry out an effective automatic landing, ac- curate information on the aircraft's attitude and position is required. In the last several years, accurate and reliable navigation systems have been developed to provide this in- formation. Such systems include inertially augmented ILS systems,1'2 microwave landing systems, MLS,3 and various attitude reference systems.4 It is anticipated that further im- provements in system accuracy and reliability will be made in the future. Touchdown errors in automatic landing are also caused by turbulent winds. In contrast with the navigation errors, there is little hope of reducing these disturbances. In fact, as lan- ding speeds are lowered, as in STOL aircraft applications, the wind effects become more pronounced.