Simulated real time controller using modified hill climbing algorithm on fixed wing airplane

In dynamic systems, it is very difficult to have models with good accuracy that are sufficient to predict the plant behavior in a way that an acceptably controlled performance can be produced. Sometimes even if mathematical models are sufficiently accurate in a way that a good controlled performance can be obtained, long term operation (or even short term in some cases) gradually increases the difference between the plant and its dynamical model. That, in turn, would lead to a degraded performance. It is a common task in industrial applications to recalibrate the control system periodically, as the plant parameters suffer various fluctuations from their original values that were used in designing the control system. The calibration procedure usually requires professional attendance, which adds up to more maintenance costs. Also, the experimental nature of the manual calibration often requires at least part of the plant operations to be halted. Adapted from MRAC framework using PID and fuzzy controller, a modified climbing algorithm was introduced in order to compensate the signal. This simulation was applied in fixed-wing airplane pitch angle in Simulink MATLAB. The result demonstrated that effectiveness of the proposed tuning algorithm and improvement over the initial non-tuned response of the process

Aeronautical Engineering: A special bibliography with indexes, supplement 64, December 1975

This bibliography lists 288 reports, articles, and other documents introduced into the NASA scientific and technical information system in November 1975

ON-BOARD ARTIFICIAL INTELLIGENCE FOR FAILURE DETECTION AND SAFE TRAJECTORY GENERATION

The use of autonomous flight vehicles has recently increased due to their versatility and capability of carrying out different type of missions in a wide range of flight conditions. Adequate commanded trajectory generation and modification, as well as high-performance trajectory tracking control laws have been an essential focus of researchers given that integration into the National Air Space (NAS) is becoming a primary need. However, the operational safety of these systems can be easily affected if abnormal flight conditions are present, thereby compromising the nominal bounds of design of the system\u27s flight envelop and trajectory following. This thesis focuses on investigating methodologies for modeling, prediction, and protection of autonomous vehicle trajectories under normal and abnormal flight conditions. An Artificial Immune System (AIS) framework is implemented for fault detection and identification in combination with the multi-goal Rapidly-Exploring Random Tree (RRT*) path planning algorithm to generate safe trajectories based on a reduced flight envelope. A high-fidelity model of a fixed-wing unmanned aerial vehicle is used to demonstrate the capabilities of the approach by timely generating safe trajectories as an alternative to original paths, while integrating 3D occupancy maps to simulate obstacle avoidance within an urban environment

A Biomimetic, Energy-Harvesting, Obstacle-Avoiding, Path-Planning Algorithm for UAVs

This dissertation presents two new approaches to energy harvesting for Unmanned Aerial Vehicles (UAV). One method is based on the Potential Flow Method (PFM); the other method seeds a wind-field map based on updraft peak analysis and then applies a variant of the Bellman-Ford algorithm to find the minimum-cost path. Both methods are enhanced by taking into account the performance characteristics of the aircraft using advanced performance theory. The combined approach yields five possible trajectories from which the one with the minimum energy cost is selected. The dissertation concludes by using the developed theory and modeling tools to simulate the flight paths of two small Unmanned Aerial Vehicles (sUAV) in the 500 kg and 250 kg class. The results show that, in mountainous regions, substantial energy can be recovered, depending on topography and wind characteristics. For the examples presented, as much as 50% of the energy was recovered for a complex, multi-heading, multi-altitude, 170 km mission in an average wind speed of 9 m/s. The algorithms constitute a Generic Intelligent Control Algorithm (GICA) for autonomous unmanned aerial vehicles that enables an extraction of atmospheric energy while completing a mission trajectory. At the same time, the algorithm automatically adjusts the flight path in order to avoid obstacles, in a fashion not unlike what one would expect from living organisms, such as birds and insects. This multi-disciplinary approach renders the approach biomimetic, i.e. it constitutes a synthetic system that “mimics the formation and function of biological mechanisms and processes.

Roll motion control of a dissymmetrical wingspan aircraft

The present study focuses on the design of a controller for an unmanned aircraft using a variable-span dissymmetric system. This is primarily intended to stabilize roll, although it was designed as a robust system for total control. The system in use is new in its application, being studied similar aircraft built to date. The aircraft for which the system has been designed is an experimental UAV built entirely at the University of Beira Interior. The stability derivatives and other data were obtained with the help of XFLR software. The development and simulation were done using MATLAB, where were tested two different control methods, LQR and Batz-Kleinman controller. A review of the flight dynamics equations for a standard aircraft was originally done, being then adapted this new concept. The interaction between the control surfaces and the response of a general aircraft was studied. An implementation of predetermined flying qualities in order to scale the state weight matrix in the LQR controller for optimal levels was also performed. At the end three separate simulations were performed to confirm the validity of the theoretical system in control and stabilization, for leveled flight when suffering disturbances, and for various equilibrium states described by a sinusoidal equation and a random variation.O presente estudo concentra-se no projecto de um controlador para uma aeronave não tripulada usando um sistema de asa de envergadura dissimétrica e variável. Este visa primeiramente estabilizar o rolamento, embora tenha sido projectado um sistema robusto de controlo total. O sistema em uso é pioneiro na sua aplicação, tendo sido estudadas semelhantes aeronaves construídas até à data. A aeronave para qual o sistema foi dimensionado é um UAV experimental construído totalmente na Universidade da Beira Interior. As derivadas de estabilidade e restantes dados aerodinâmicos foram obtidos com a ajuda do software XFLR. O desenvolvimento e simulação foram realizados em software MATLAB, para o qual são testados dois métodos de controlo distintos, com LQR e controlador Batz-Kleinman. Foi inicialmente feita uma revisão das equações da dinâmica de voo para uma aeronave generalizada, sendo depois adaptado o novo conceito em estudo. A interacção entre as superfícies de controlo gerais e a resposta de uma aeronave foi estudada. Uma implementação de qualidades de voo pré-determinadas com vista a dimensionar a matriz de pesos de estado no controlador LQR para níveis óptimos foi também realizada. No final foram feitas três simulações distintas para confirmar teoricamente a validade do sistema no controlo e estabilização, em voo nivelado sofrendo perturbações, e consoante pontos de equilíbrio pré-determinados segundo uma equação sinusoidal e para uma variação aleatória

Aeronautical Engineering: A special bibliography, supplement 60

This bibliography lists 284 reports, articles, and other documents introduced into the NASA scientific and technical information system in July 1975

Aeronautical engineering: A continuing bibliography, supplement 122

This bibliography lists 303 reports, articles, and other documents introduced into the NASA scientific and technical information system in April 1980

Trajectory optimization and guidance law development for national aerospace plane applications

The work completed to date is comprised of the following: a simple vehicle model representative of the aerospace plane concept in the hypersonic flight regime, fuel-optimal climb profiles for the unconstrained and dynamic pressure constrained cases generated using a reduced order dynamic model, an analytic switching condition for transition to rocket powered flight as orbital velocity is approached, simple feedback guidance laws for both the unconstrained and dynamic pressure constrained cases derived via singular perturbation theory and a nonlinear transformation technique, and numerical simulation results for ascent to orbit in the dynamic pressure constrained case

Longitudinal flying qualities criteria for single-pilot instrument flight operations

Modern estimation and control theory, flight testing, and statistical analysis were used to deduce flying qualities criteria for General Aviation Single Pilot Instrument Flight Rule (SPIFR) operations. The principal concern is that unsatisfactory aircraft dynamic response combined with high navigation/communication workload can produce problems of safety and efficiency. To alleviate these problems. The relative importance of these factors must be determined. This objective was achieved by flying SPIFR tasks with different aircraft dynamic configurations and assessing the effects of such variations under these conditions. The experimental results yielded quantitative indicators of pilot's performance and workload, and for each of them, multivariate regression was applied to evaluate several candidate flying qualities criteria

Trajectory Control for Very Flexible Aircraft

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76453/1/AIAA-29335-906.pd