Sharif Digital Repository

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... 

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. ... 

A cooperative aerial system to defense a Ground Station (GS), against an Incoming aerial Targets (IT) is presented. GS is surrounded by given terrains and a group of homogenous Unmanned Aerial Vehicles (UAVs) are employed using a novel online guidance algorithm in a decentralized manner. The proposed algorithm includes loiter, midcourse and terminal phases. During loiter; UAVs follow an optimal circular path. IT is supposed to approach GS along an optimal low altitude trajectory with respect to the terrains. UAVs are informed the initial position and velocity of IT and they are unaware of IT trajectory. Each UAV decides on whether to engage with IT or not, and shares its decision with other... 

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... 

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... 

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 project, process of conceptual design and design optimization is presented for a cloud seeding UAV. Inefficiency of classical and statical design approaches is more obvious in new designed missions restricted to different and numerous Dynamic and performance constraints with no similar design target aircraft. So in this project we used conceptual design optimization approach with respect to aerodynamic, weight and balance, performance and stability discipline to overcome those restrictions and to design a cloud seeding UAV. In order to reduce the computational time, we used low fidelity method (analectic equation) in performance and stability, medium fidelity method (empherical... 

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... 

Using unmanned aerial vehicles in aerial payload carrying leads many changes requiring significant study and research. In recent years, there has been considerable maturation in Micro Aerial Vehicles (MAV) developement especially quadcopters. In addition to the endurance restriction, considerations on volume and weight that can be carried, and safety issues are also obstacles to the development of unmanned aerial payload carrying in urban environments. One of the ways to make a quadcopter more agile while carrying a load is to hang the cargo from the quadcopter via a cable. In this way, it is possible that quadcopters carry the cargo in a cooperative way, which if properly arranged,... 

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... 

In this study, integrated navigation systems that utilize velocity-matching algorithm and are used in automatic landing of Unmanned Aerial Vehicles (UAV) are investigated. At first, the accuracy of the navigation system in the landing phase is analyzed and the relationship between the accuracy of inertial sensors, flight parameters and the accuracy of the navigation system is derived analytically. Then, by integrating the dynamic model of the UAV and the inertial measurement unit, a new algorithm for navigation of fixed-wing UAVs is presented. The integration mechanism of the proposed algorithm is tightly coupled; hence, it is capable to eliminate the errors of UAV model and inertial system.... 

In this project, the final goal is to create a team consisting of a UGV and a quadrotor capable of relative tracking and coordinated landing, with focus on quadrotor control. What we mean by cooperative control in this project is control of quadrotor for the purpose of cooperation with a UGV; This should not be mistaken with another sense of cooperative control in which the control algorithms are developed for both of the robots or are based on the interactive dynamics of the robots.In order to accomplish this goal, an experimental testbed consisting of a quadrotor and a UGV capable of communication and data exchange was developed as a first step. The quadrotor was constructed using... 

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 this project, a method for cooperative search and localization of RF ground moving targets by a group of UAVs is developed. It should be noted that UAVs are just equipped with GPS and directional sensors. Since there is fuel constraint for UAVs, they take fuel from a tanker whenever they require. Moreover, searching method enables the UAVs to see different parts of the desired area with almost uniform distribution. In addition, the proposed approach enables the UAVs to perform a local search with the aim of finding the targets having lost their signal during localization mode. Finally, based upon a fueling decision function the UAVs take turn, approach to the fuel tanker, and start... 

The aim of this study is to develop a new algorithm to perform high performance and precise maneuvers for variety of fixed-wing UAVs. Iterative learning in conjunction with an adaptive control technique is developed here for this purpose. In this research, the guidance and control laws are initially developed by classic algorithms that exist in most of commercial autopilot systems. Then, the learning algorithm is combined with the classic autopilot system to improve trajectory tracking performance. The algorithms have been tested by simulation in the loop technique, utilizing Simulink and X-Plane software. So, the navigation data was provided by the X-Plane, solving dynamic equations, and... 

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... 

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.... 

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...