Sharif Digital Repository

The purpose of this thesis is to control the attitude of a tail-sitter UAV in transition phase (from hover to cruise and vice versa). This UAV has a pusher shrouded fan propulsive. Due to the fact that in transition phase the dynamic model of the UAV is associated with a significant uncertainties and the stability is more important than the performance, robust controller has been used. The propulsion part of the tail-sitter UAV can be assumed as a separate ducted fan UAV. In the first step both UAVs have been designed. then, in order to have an accurate model of UAV, the dynamics of actuators, including the engine and servo motor, has been identified. Then, modeling and verification for both... 

The problem that we will solve in this thesis is the automatic landing using model predictive control. Due to the large growth in the use of fixed wing UAVs and the challenges faced by these type of UAVs with respect to other types of UAVs, in this project, the automatic landing of a UAV will be studied in the presence of variable uncertainties with time that will be considered in the modeling. The airplan is assumed to have inertial sensors, gps, speedometer and altimeter. The innovation of the thesis is that until now, Adaptive Model Predictive Control has not been used to control the fixed wing UAV landing. One of the weaknesses in Model Predictive Control is the loss of performance in... 

Hand-launched UAVs are type of unmanned aerial vehicles that due to transportability and geometric specification, are operationally valuable and worthy. reconnaissance & surveillance (aerial mapping, aerial filming, inspection, border protection); health care (blood transport, body organ transport, medicine delivery); agriculture (farm monitoring, fertilization, cloud seeding); payload delivery (envelopes posting); network covering (internet supply, telecommunication relay); crisis management (remote area medical) are some of typical applications and missions of this type of aircrafts. These UAVs have almost low altitude short endurance (below 5000 ft. and less than 2 hrs.). To extend their... 

Cost Estimation plays an essential and role in UAV (Unmanned Aerial Vehicles) Projects. By increasing the complexity of new unmanned systems, the importance of this task augments. Additionally, up to now, a comprehensive approach has not been adopted internationally. But in parallel a number of international companies and organizations has developed specific methods by themselves; confined to their corporate.
This project pursues developing a complexity-based model for cost estimation of unmanned aerial vehicles, especially Jet UAVs. However, it’s anticipated that this model may be utilized for all kind of systems, but it seems that jet UAVs use it with a better and more reliable... 

Topic that is investigated in this article include identify and localization a number of aerial target penetrating into a protected by area by a swarm of UAVs is fixed wing. UAVs do not have any prior notice of positioning targets. In addition, it is assumed that lacks any radiation exploitable targets and thus use UAVs for Targets Detection from an active radar system. Obviously this article focus on developing a guidance algorithm UAVs to this particular issue and also as the targets participatory is localization algorithm. In addition, extraction type and performance characteristics radar system required and also performance characteristics of the class of UAVs, which is suitable to... 

The use of drones in various fields is increasing. One of the applications that can be mentioned for drones is humanitarian areas can include drug supply chains, blood supply chains, relief chains, and the like. The use of these unmanned vehicles in humanitarian areas poses legal challenges compared to other areas. This study aimed to investigate drones following a disaster, the essential role of UAVs, and a vehicle to carry out relief operations. Following a disaster, infrastructure can be severely damaged, and the destruction of infrastructure can reduce the efficiency of land vehicles. In this research, “drone and vehicle routing problem” have been done to provide relief and minimize the... 

In the present study, an attempt has been made to design and develop a nano drone using the dynamics of single-wing drones. To reduce the noise associated with nano-drone motors, a unique magnetic system has been developed for the drone's propulsion system, which has technology similar to magnetic trains and uses the theory of magnetic suspension, which is one of the main innovations of this dissertation. The drone designed in this research will have a blade with a radius of 15 cm and its total weight will be 170 grams, which according to the thrust of the blade will be able to carry a load of 50 grams for 14 minutes. In this research, after the initial design of the drone and related... 

Identification of an Unmanned Aerial Vehicle(UAV) helicopter dynamics using artificial Neural Networks and Frequency-Response methods is implemented in this project. An 8Degree Of Freedom (DOF) helicopter simulator based on X-Cell 60 helicopter is developed in order to obtain simulation data for identification. CIFER techniques, as a reliable and powerful tool in frequency-domain identification, are utilized. For time-domain identification, Nonlinear Auto Regressive Exogenous (NARX) as well as Recurrent Modified Elman Neural Networks are examined. Two neural models are presented to be usedas a predictor in flight control systems and to perform as a helicopter simulator independently.... 

The purpose of this thesis is to control altitude and attitude of a Tilt Tri-Rotor UAV in rotorcraft mode and control of altitude, attitude and forward velocity in transition mode (from rotorcraft mode to cruise) by using model predictive control. First, the detailed mathematical model is obtained by the Newton-Euler equations of motion, in both rotorcraft and transition modes. In the next step, a MIMO model predictive controller has been designed, considering input constraints. Then, since, robustness of the model-based control approach is an important challenge, the performance of the controller is presented in the presence of model uncertainties and wind disturbances. The results indicate... 

Aerodynamic shape optimization has been always of great importance in aerospace design. Recent advancements in computational algorithms and hardware, has made it feasible to have advanced optimization as a standard part of desing procedure. Here we have promoted aerodynamic optimization in three different applications, i. e., wing-body configuration, hydro propellers, and air propellers. First we have reviewed fluidic theoretical aspects, and have selected appropriate physical models or existing softwares. Accuracy of physical analysis or software is validated. Then different optimization algorithms are reviewed, and schemes used in this thesis are described and the softwares are validated. ... 

In recent years, the area of research on micro flying robots has been developed, because of the development in micro manufacturing technologies. These flying robots can be used in military and Civilian missions such as identifying, espionage, aerial relays, traffic surveillance rescue, help and…because of their advantages. Ability to fly in finite areas, no human injuries, low manufacturing and power cost, easy and fast Application, Easy Maintenance and … are some advantages of these robots. We can control these robots manually by RC remote controllers or by Auto guidance system. On the other hand, these robots are used in research laboratories for testing new control algorithms such as ... 

In recent years, the area of research on micro flying robots has been developed due to the development in micro manufacturing technologies. Due to extra advantages of these flying robots, they are implemented in military and civilian missions such as identifying, espionage, aerial relays, traffic surveillance, rescue, aid, etc. Ability to fly in specified areas, without human injuries, low manufacturing and energy costs, easy and fast implementation, Easy Maintenance, etc, which are some advantages of these robots. We can control these robots manually by remote controllers (RC) or by Auto guidance systems. On the other hand, these robots are used in research laboratories for testing new... 

In the past few decades, regarding the advancement of science and technology, the application of Unmanned Aerial Vehicles (UAVs) are increasingly on the rise. One of these applications is to search and localize ground targets. Among the advantages of drones, removing the manpower to carry out exploration and positioning is one of the most important benefits. This feature can reduce the risk of mission, reduce the burden of the plane and increase the height and range of operations. On the other hand, using a group of intelligent robots to increase speed and accuracy in the mission, is one of the topics that have been discussed in recent years. By merging these two topics and utilizing a... 

In this thesis, an identified dynamic model of a fixed wing UAV, known as WAYO, is presented. To do so, frequency domain system identification technique is utilized. Due to physical and environmental constraints, it was impossible to carry out precise flight tests of the aircraft in all flight phases. Instead, a small-sized UAV, called Twin Star-BL was selected to carry out the tests and to validate the simulation model. In both cases (WAYO and Twin Star-BL) transfer functions were obtained using frequency responses and employing extensive identification process. Identified models were then assessed using time domain data for different test records. Finally, handling qualities of both aerial... 

Today, for construction of UAV, designers are interested in and trying for substitution of composite material instead of metal. They would rather use composite structures due to lower costs of construction, availability, along with high ratio of strength to weight of this material, while metal structures are mainly rare and too expensive for construction of UAV. For instance, unavailability of aluminum metal and complicated methods of construction of aluminum wings with using of special tools, justifies using of composite with easier construction, abundant, and cheaper materials. The main goal of this project is redesign of aluminum wing of a jet engine UAV, In fact, by doing some structural... 

In recent years, autonomous unmanned aerial vehicles (UAVs) have attracted considerable amount of interest because of a wide area of applications and a lot of advantages. UAVs have been extensively used for military operations that include tracking, surveillance, active engagement with weapons and airborne data acquisition. UAVs are also in demand commercially due to their advantages in comparison to manned vehicles. These advantages include lower manufacturing and operating costs, flexibility in configuration depending on customer request and not risking the pilot on demanding missions. Quadrotor, which is a kind of rotary wing UAVs, has many advantages such as the vertical take-off and... 

In this study, the cooperative inertial navigation systems are used to prevent the error growth of the inertial navigation system in unmanned aerial vehicles that fly in group. Here, the navigation problem is defined for a group of unmanned vehicles, flying with full six degrees of freedom and the objective is to estimate the navigation information of all cooperators. Due to the nonlinear equations, the decentralized extended Kalman filter is used to estimate the states of the system. This means that there is a Kalman filter in each vehicle. The inputs of this filter are the range and the bearing angles between the vehicle and the cooperators, the estimated position of the cooperators and... 

Over the past two decades, the production of ultra-light drones has increased dramatically. These aircraft are used in applications such as filming, surveying, etc. One of the most important goals is to fly them for a long time. From time immemorial, a lot of work has been done to get such birds to fly, but nothing has ever been done on their engines and propellers, and they have always been considered ideal models (in other words, their efficiency is a bit ideal). In this dissertation, the main purpose is to study some of these sets and to obtain the flight time of a particular drone. First, a low-velocity wind tunnel was built to examine these complexes, then we tested these complexes... 

In this study, a multiple model wind estimator is proposed to detect the wind type and to estimate the wind components as well as the states of a fixed-wing UAV without any direct measurement of the air data. Then, the identified wind model and the estimated states are compensated in the heuristic nonlinear model predictive controller during landing phase. For this purpose, a static multiple model approach is taken, comprised of four independent extended Kalman filters, each one is estimating the wind based on one of the four wind models including a constant wind, a “1-cosine” model, a wind shear and a microburst.Moreover, a new heuristic multiple model filter, called Multiple Model Extended...