Flight Path Angle Control Research Articles

Adaptive Fault-Tolerant Finite-Time Flight-Path Angle Control for Aircraft Systems With Unknown Deadzone and Actuator Faults

Adaptive Fault-Tolerant Finite-Time Flight-Path Angle Control for Aircraft Systems With Unknown Deadzone and Actuator Faults

A Novel Hybrid Robust Control Design Method for F-16 Aircraft Longitudinal Dynamics

This paper presents a hybrid robust control design method for a third-order lower-triangular model of nonlinear dynamic systems in the presence of disturbance. In this paper, a novel control design is presented systematically to synthesize a robust nonlinear feedback controller, called backstepping sliding mode control (BSMC), for the proposed system by a combined approach of backstepping design and sliding mode control. In this approach, a family of the “sliding surface” is introduced in state transformations. Then, a smooth switching function of the sliding surface is introduced and enforced to include in virtual feedbacks and a real control law from the control selection phrases of the backstepping design loop. The achieved control method proves a well-tracking command with asymptotic stability, provides a robustness in the presence of uncertainties, and eliminates completely a chattering phenomenon. The application of flight-path angle control corresponding to the longitudinal dynamics of a high-performance F-16 aircraft simulation model is implemented. Under some assumptions, full nonlinear longitudinal dynamics is reformed into a lower-triangular system for a direct application to formulate a control law. A closed-loop system is achieved for in-flight simulation with different flight profiles for a comparison of the existing methods. Also, an external disturbance on different loading/unloading conditions in flight is applied to verify and validate robustness of the proposed control method.

Performance Improvement of an Unpowered Auto-landing Guidance for UAV Under Steady Wind Conditions

The unpowered landing of an aircraft is a highly risky process because it can only use kinetic and potential energy. Especially, if a landing site is designated, the risk of unpowered landing is dramatically increased due to the limitation of available energy. For this reason, an appropriate method is required for safe landing and many studies have been conducted to accomplish this purpose. In this paper, we study a scheme to improve the performance of an unpowered auto-landing for an unmanned aerial vehicle. The method presented in this paper focuses on the performance improvement of an unpowered auto-landing under steady wind conditions. To achieve this, simple modifications of the autopilot which complement the heading controller and the flight-path angle controller are proposed. The proposed method is evaluated by numerical simulation.

Longitudinal flight control laws for high aspect ratio light utility aircraft

The development of Flight Control Laws (FCLs) for high aspect ratio light utility aircraft have been previously accomplished by considering each control module to be independent. For the longitudinal motion, the FCLs comprise mainly the airspeed control and the flight path angle control. In addition, the altitude control and the vertical speed control have been designed based on the design of flight path angle control. Further investigation is conducted to reveal possibility to design the longitudinal control, i.e. airspeed and flight path angle control by considering the coupling behavior between both controls but still utilizing the same control design strategy that is the advanced Proportional-Integral (PI) control technique. The paper shows the concept and architecture of coupled longitudinal flight control laws, the design strategy chosen, implementation to the aircraft model and investigation of control performance. The results achieved from this research are the architecture and procedure to design longitudinal FCLs. Additionally, knowledge of coupling control behavior between the airspeed and flight path angle via aircraft simulations is acquired.

Autonomous Landing Control of Fixed-wing UAVs: from Theory to Field Experiment

This paper describes our work on autonomous landing control of fixed-wing unmanned aerial vehicles (UAVs). A hierarchical control structure is developed for autonomous landing of fixed-wing UAVs. In the hierarchical control structure, active disturbance rejection controllers are designed for attitude control. A proportional guidance law is proposed for height tracking. Other controllers, such as flight path angle controller, heading angle controller and taxiing controller, are designed using proportion integration differentiation technique. A test system is developed to validate the hierarchical structure and narrow the gap between the theory and practice. The test system includes an X-Plane based hardware-in-the-loop(HIL) simulation subsystem and a flight test subsystem. The interface and protocol between the autopilot and X-plane are designed same with that of the flight test platform. Consequently, the autopilot passed the validation in the HIL simulation can be directly moved on to the flight test platform. Finally, results of the HIL simulation and field experiment are presented to demonstrate the performance of the proposed approach and the entire test system.

OPTIMAL IMPACT ANGLE CONTROL GUIDANCE LAWS AGAINST A MANEUVERING TARGET

Optimal impact angle control guidance law and its variants for intercepting a maneuvering target are introduced in this paper. The linear quadratic(LQ) optimal control theory is reviewed first to setup framework of guidance law derivation, called the sweep method. As an example, the inversely weighted time-to-go energy optimal control problem to obtain the optimal impact angle control guidance law for a fixed target is solved via the sweep method. Since this optimal guidance law is not applicable for a moving target due to the angle mismatch at the impact instant, the law is modified to three different biased proportional navigation(PN) laws: the flight path angle control law, the line-of-sight(LOS) angle control law, and the relative flight path angle control law. Effectiveness of the guidance laws are verified via numerical simulations.

Adaptive integral dynamic surface control of a hypersonic flight vehicle

In this article, non-linear adaptive dynamic surface air speed and flight path angle control designs are presented for the longitudinal dynamics of a flexible hypersonic flight vehicle. The tracking performance of the control design is enhanced by introducing a novel integral term that caters to avoiding a large initial control signal. To ensure feasibility, the design scheme incorporates magnitude and rate constraints on the actuator commands. The uncertain non-linear functions are approximated by an efficient use of the neural networks to reduce the computational load. A detailed stability analysis shows that all closed-loop signals are uniformly ultimately bounded and the tracking performance is guaranteed. The robustness of the design scheme is verified through numerical simulations of the flexible flight vehicle model.

UAV Flight Path Control Using Contraction-Based Back-stepping Control

In this paper, a contraction-based backstepping nonlinear control technique was proposed. The proposed controller synthesis technique utilizes both the recursive nature of backstepping control and of contraction analysis. This approach results in a contracting closed-loop dynamics, with exponential stability. The use of the hierarchical contraction form in the control problem formulation also results in the exponential convergence of controlled variables and can be easily applied to non-autonomous systems. A flight path angle controller was synthesized and simulated using the proposed technique to demonstrate the exponential convergence achieved by the backstepping controller design.

Adaptive dynamic surface control of a hypersonic flight vehicle with improved tracking

AbstractThis work presents a nonlinear adaptive dynamic surface air speed and a flight path angle control design procedure for the longitudinal dynamics of a generic hypersonic flight vehicle. The proposed design scheme takes into account the magnitude, rate, and bandwidth constraints on the actuator signals. A new approach is used to enhance tracking performance and avoid a large initial control signal. The uncertain nonlinear functions in the flight vehicle model are approximated by using radial basis function neural networks. A detailed stability analysis of the designed controllers shows that all the signals of the closed‐loop system are uniformly ultimately bounded. The robust performance of the design scheme is verified through numerical simulations of the flight vehicle model for various parameter variation test cases.Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society

Adaptive Dynamic Surface Control of a Hypersonic Flight Vehicle with Magnitude, Rate and Bandwidth Constraints

AbstractThis paper describes the design and analysis of a nonlinear adaptive dynamic surface air speed and a flight path angle controller for the longitudinal dynamics of a generic hypersonic flight vehicle with actuator constraints. The uncertain nonlinear functions in the flight vehicle model are approximated by using radial basis function neural networks. Controller design for the velocity subsystem and the purefeedback flight path angle subsystem are treated independently. The salient feature of the design is the accommodation of magnitude, rate and bandwidth constraints on the actuator signals. A detailed stability analysis of the designed controllers shows that all the signals of the closed loop system are uniformly ultimately bounded. The robustness and performance of the designed controllers is verified through numerical simulations of the flight vehicle model for various parameter variation test cases.

Mars exploration rovers navigation results

The twin Mars Exploration Rovers, Spirit and Opportunity, were launched on June 10, 20033 and July 8, 2003, from Cape Canaveral, Florida. Spirit and Opportunity were targeted for landings at Gusev Crater (arrival on January 4, 2004) and Meridiani Planum (arrival on January 25, 2004). The primary navigation challenge was to deliver each spacecraft to the desired atmospheric entry interface point with sufficient accuracy such that each lander would touch down within a specified landing ellipse (about 70 km × 5 km) determined to be safe for landing and also judged to be scientifically interesting. In order to achieve landing within the target ellipse, precise control of the inertial entry flight path angle (FPA) at atmospheric entry was required. The maximum allowable errors in FPA following TCM-5 (trajectory correction maneuver #5) at Entry (E) — 2 days were ±0.12° (3σ) for Spirit and ±0.14° (3σ) for Opportunity. Achieving these entry delivery accuracies necessitated significant improvements to the interplanetary navigation system used for MER. These improvements included new processes and software for orbit determination, propulsive maneuver design, and entry, descent, and landing (EDL) trajectory simulation. The actual achieved atmospheric entry accuracies for Spirit and Opportunity significantly exceeded the requirements. At the navigation data cutoff for the TCM-5 final design, the orbit determination FPA knowledge error was ±0.028° (3σ ) for Spirit and ±0.035° (3σ ) for Opportunity. Because of exceptionally accurate navigation performance, TCM-5 (E — 2 days) and TCM-6 (E — 4 hours) were canceled for both Spirit and Opportunity. The actual landing locations (determined from in-situ Doppler tracking between the MER rovers and the Mars Odyssey orbiter) differed from the target landing points by 10.1 km (downtrack) for Spirit and 24.6 km (downtrack) for Opportunity. The majority of the landing position offsets for both landers was primarily caused by variations in atmosphere and spacecraft aerodynamic modeling from what was predicted. The amount of the landing position offset caused by navigation-only errors was only 3.3 km (uptrack) for Spirit and 9.7 km (downtrack) for Opportunity.

Backstepping-Based Flight Control with Adaptive Function Approximation

A command filtered backstepping approach is presented that uses adaptive function approximation to control unmanned air vehicles. The controller is designed using three feedback loops. The command inputs to the airspeed and flight-path angle controller are x c , γ c , V c and the bounded first derivatives of these signals. That loop generates comand inputs μ c , α c for a wind-axis angle loop. The sideslip angle command β c is always zero. The wind-axis angle loop generates rate commands P c , Q c , R c for an inner loop that generates surface position commands. The control approach includes adaptive approximation of the aerodynamic force and moment coefficient functions. The approach maintains the stability (in the sense of Lyapunov) of the adaptive function approximation process in the presence of magnitude, rate, and bandwidth limitations on the intermediate states and the surfaces.

必要加速度ベクトルに基づいた，航空機の方位角・経路角制御の一方法

必要加速度ベクトルに基づいた，航空機の方位角・経路角制御の一方法

Analyzing the flared landing task with pitch-rate flight control systems

A closed-loop handling qualities methodology is applied to an analysis of the flared landing task with pitch-rate flight control systems. A model of pilot behavior throughout approach and flare is developed which postulates the manner in which the pilot may move from pitch attitude to flight path angle control. Twenty-five configurations flight tested on the NC-131H Total In-flight Simulator aircraft are analyzed using a structural pilot model ad a handling qualities methodology previously reported in the literature. Closed-loop simulation of the simplified landing task is undertaken using the structural model. The pilot ratings from flight test extended the data base supporting the utility of a model-based handling qualities metric. A handling qualities sensitivity function is introduced which may have potential as a design tool.