Research Interest
In AFASL, our research interest is on the developing and combining different techniques and methodologies to design, analyze, control, and optimize the different types of unmanned aerial and aquatic systems (e.g., fixed wing, flapping wing, tilt-rotor/wing, morphing, space, and marine drones, and underwater robots.) at a reduced computational cost. The focus is on developing new conceptual design, methodologies, and bioinspiration from natural avian and aquatics, such as birds, insects, and marine organisms in order to design and enhance the performance of these robotic systems. We propose methodological, theoretical, and experimental research on bioinspiration, biomimetic, autonomous aerial and aquatic systems, and other topics relevant to the field, with improved capabilities in aerodynamics, hydrodynamics, structure, aeroelasticity, fluid-structure interaction, actuation mechanisms, stability, material and manufacturing techniques. We develop experimentally-validated reduced-order or high fidelity models for these multidisciplinary robotic systems in order to design and manufacturing some efficient prototypes which can participate in the progress of the emerging technologies.
Unmanned Aerial systems
Separation and Swarming Flight of Drones: We are interested in design, manufacturing, and control of new concepts for separation and swarming drones. We propose some new concepts of UAVs which are able to convert to several MAVs. Being in form of a UAV means having more endurance and higher altitude due to the long wingspan and high aspect ratio. The decomposition and separation ability of the UAV to five MAVs solves several problems and provide benefits in flight mission. In three conditions, the UAV can be converted to MAVs. First, when the UAV is attacked or has defect, the intact parts separate and pursue the mission. Second, when the drone is supposed to increase its video covered area, in this mode, with separation of MAVs, five micro air vehicles with five cameras can scan or map out a vaster area than one single UAV. Third, when the micro drones want to increase their stealth property, MAVs can perform a swarm flight. Similar concepts will be proposed for other drones with different configurations. These types of drones also can scarifies a part of their body in danger (like lizards) while still will be able to fly. Fore more details click on the link.
Application of Swarming Drones for Cellular Phone Network Loading and Field Tests : Cellular network operators have problems to test their network without affecting their user experience. Testing network performance in a loaded situation is a challenge for the network operator because network performance differs when it has more load on the radio access part. In this project, deploying swarming drones is proposed to load the cellular network and scan/test the network performance more realistically. Besides, manual swarming drone navigation is not efficient enough to detect problematic regions. Hence, particle swarm optimization is proposed to be deployed on swarming drone to find the regions where there are performance issues. Swarming drone communications helps to deploy the particle swarm optimization (PSO) method on them. Loading and testing swarm separation help to have almost non-stochastic received signal level as an objective function. Moreover, there are some situations that more than one network parameter should be used to find a problematic region in the cellular network. It is also proposed to apply multi-objective PSO to find more multi-parameter network optimization at the same time.
Performance Enhancement and Load Balancing of Swarming Drones Through Position Reconfiguration: There is currently a growing interest in the area of drag reduction of unmanned aerial vehicles. In this project, the swarming flight of the fixed-wing drones and a load balancing mechanism during the swarm is investigated. As an example, the swarm flight of EBee Sensfly flying wings is analyzed through the proposed methodology. The aerodynamic drag forces of each individual drone and the swarm are modeled theoretically. It is shown that drones through the swarming flight can save up to 70 % of their energy and consequently improve their performance. As swarming drones have different loads and consuming a different level of power depending on their positions, there is a need to replace them during the flight in order to enhance their efficiency. To this end, regarding the number of drones, a replacement algorithm is defined for them so that they will be able to save more power during their mission. It is shown that there is more than 21 percent improvement in flight time and distance of swarming drones after replacement. This method of replacement and formation can be considered as one of the effective factors in a drag reduction of swarming aerial vehicles.
Delivery Drones: We are interested in design and manufacturing new concepts of drones for high distances cargo delivery. Package delivery is starting to integrate drones as a cheaper alternative to conventional delivery services. The development of robust and stable aircraft capable of delivering parcels is a requirement for these missions. Recently, one of the applications which has attracted the attention of different companies is drone delivery service where different types of products can be transported by them. For example, Amazon, Google, and USPS and FedEx post service in United States have employed drones to deliver packages to customers. The rotary wings concepts, such as quadcopters have been proposed for destination with low distances and low weight cargoes. The drawbacks of the existing delivery drones include low flight range, low flight altitude, urban obstacles, depending on climate conditions, cargo size and weight limitation, and low endurance. In AFASL research group we aim to propose some new stable concepts of vertical takeoff landing drones which can be efficiently navigated in diverse situations.
Solar Drones: The diverse application of drones has debated to the fact that engineers do research on optimizing the performance of these flying vehicles. For the micro drones, one of the challenging issues is their high power consumption to the limited power capacity due to their weight limitation. Nowadays, applying solar panels on drones is considered as a common method to increase the flight endurance. The provided energy form solar cells can be used for motors and other systems of drones. In solar systems, usually battery is used as a backup when the solar cells cannot produce enough power flying under the cloud or in the dark. In other words, a hybrid source which is combination of the solar cells and battery is usually used for powering drones. Solar cells which are thin, flexible, low weight, and efficient are applied on the wings of different types of drones. Therefore, in AFASL research group we plan to work on design, manufacturing, and performance enhancement of solar drones with different configurations.
Amphibious and Marine Drones: There is a growing interest for the use of marine drones in military and civilian applications to eliminate the risk of human involvement in marine environment and to provide cheaper alternatives to larger flight vehicles. The proposed systems will be marine drones that blend in with nature and can fly, dive, and swim with better endurance, or the drones that can be launched from submarines to perform different type of the missions in marine environment. In other words, one of the key tasks in this effort will be the development of novel designs of marine drones that can combine the flying, skimming, and swimming of unmanned marine vehicles and design of novel launcher systems. The another goal of this research is studying the fundamental of diving avian and insects to be inspired for flying and swimming amphibious unmanned aerial systems in different configurations. This research will encompass a conceptual design process, aerodynamic and hydrodynamic analyses, navigation, control, and guidance techniques, new technologies to improve the endurance of the drones, and material and fabrication of the prototypes.
Space and Planetary Exploration
Space Drones: We also do research on new designs and concepts for space and planetary explorations. For example new concept of drones with morphing and vertical-takeoff-landing capabilities are proposed which will be able to fly in other solar bodies, including Mars, Venus, and Titan environments for planetary exploration. In this part of our research we work on design and manufacturing of solar drones for Venus exploration; mission define, design, and manufacturing of fixed wing, flapping wing, morphing, and VTOL drones for Mars exploration; research on high performance airfoils for low Reynolds numbers; swarming flight on Mars; energy harvesting in Mars for space drones, and mission define and design of soaring fixed wing drones for Titan.
Venus drones: Venus has a harsh environment that makes its exploration especially difficult. Standard rovers like on Mars would not work as the intense temperature and pressure would cause them to have a short operating time. At an altitude of about 55 km Venus has an Earth-like atmosphere where a robotic system could survey for different features. A fixed-wing drone that can fly at this altitude would be practical. To obtain better information on Venus, the UAV can fly at lower altitudes, until pressure and temperature operational limits are met. Then the drone can come back to an altitude of 55 km and alleviate until it is ready to go back into the lower altitudes. The atmospheric analysis is done to model Venus’ characteristics at lower altitudes between 0 km and 60 km. Functions made that model the atmospheric properties of Venus, temperature, pressure, density, and viscosity, were then used to investigate the wing and thrust loading of a fixed-wing UAV in Venus. The results from this wing and thrust loading investigation where that wing loading and thrust loading increase with altitude. Specifically, thrust loading increases between 35 km and 55 km, and decreases between 0 km and 30 km. There is an altitude where the minimum thrust loading is needed for a constant wing loading, and this is found at a range between 15 km and 30 km. At higher wing loading values, like 80 N/m2, the minimum thrust loading is at about 20 km. At lower wing loadings, like 10 N/m2, the minimum thrust loading is at 15 km. This study gives outlines for future steps of designing fixed-wing UAVs for Venus exploration.
Planetary Exploration by Self-Cleaning Solar Rovers: A small rover has been constructed to serve as a Mars rover model on which a cleaning mechanism has been prototyped. To test the cleaning mechanism and the solar panel surveying software that identifies when to clean, a 52×32 cm solar panel has been fixed atop the model rover. The general idea behind the cleaning mechanism is two solar panel wipers made from a low-density foam driven by high torque servos. The servos interchange the cleaning motion, while one rotates across the solar panel, the other waits until the first servo is finished, then it begins its cleaning motion. A quick analysis of the Mars environment was done to have a better idea as to what cleaning methods would work best. Mars is mainly fine dust at the surface, making the porous foam wipers a good choice as finer dust gets picked up by the wiper instead of sticking to the solar panel surface. The pliable foam also allows for a better seal between the solar panel and itself as it expands into the solar panel surface. After some simple testing the solar panel cleaning mechanism worked as intended, but a better method can be established by specifically testing with dust that has similar properties to the one on Mars. Using a camera to monitor the solar panel, and act as a sensor that provides the system with information as to when to clean the solar panel worked well. Further investigations into how accurate the program’s solar panel obstruction sensing is through statistical analysis of accuracy, precision, and resolution can be performed.
Bioinspiration & Biomimetics
Bioinspired Morphing Drones: One of the interesting aspects of avian flight dynamics is how natural flyers, such as birds and insects can deform their shape to optimize their flight in different flight modes. For most of the birds, these changes take place through morphing of the wings. Therefore, the concept of a morphing drone originated from the observation of birds as they flew. Birds have a unique ability to change several aspects of their wings and body mid-flight in order to alter velocity, altitude, and maneuverability or to save energy. Some examples of these mid-flight morphing abilities include spanning and sweeping which can occur during the flight modes, such as diving, flapping, gliding, soaring, turning, and landing. Furthermore, birds are also capable of modifying their winglets, either expanding them causing decreased velocity and altitude or compressing them creating the opposite effect. Inspired from natural flyers, the evolution of unmanned aerial vehicles has advanced drastically over the past few years and due to the birds morphing capabilities; they are an ideal study subject to base the design of morphing drones upon. Based upon the research witnessed in birds, insects, and bats and their morphing capability, in AFASL we do research on developing new bioinspired concepts of morphing in different types of drones in order to improve their endurance, altitude, velocity, maneuverability, compressibility, stealth, and/or payload.
Energy Conservation of V-Shaped and Echelon Flocking Migrating Birds through Leader and Tail Switching: Migrating birds take advantage of V-shaped flocking to reduce the required energy for their flight. Studies have shown that the birds in different positions in V-shaped flight contend with different drag forces. Lead and tail birds have to overcome more drag forces than the other birds in V-shaped flock. Some kinds of flocking birds re-positioning observation have been reported. This observation is interpreted in another context rather than its aerodynamic aspects. This research presents the re-positioning aerodynamics analysis of the V-shaped flocking birds and its energy-saving consequences. This analysis proves that how the birds like Canada geese can fly very far in a single day through repositioning. Extensive analysis shows that leader and tail positions switching of fourteen Canada geese can improve the flight range and endurance of these migrating birds more than 44.5%. This study gives the guidelines for energy saving and optimization of flocking migrating birds through evolution.
Bioinspired Drag Reduction Techniques from Avian and Aquatics: With the present energy crisis around the world, there is an ever increasing need for doing research in drag reduction and performance enhancement techniques. Since the nature has developed processes, objects, materials, and the functions to increase its efficiency, it has the best answers when we seek to improve or optimize a system. Thus, the fields of biomimetics and bioinspiration allow us to mimic biology or nature to develop methods for reducing drag in all types of transportation involving land, sea, and air. In this research study, Our lab focus on examining (by theory and experiments) different mechanisms employed by biological aquatic systems and avian for performance enhancement and drag reduction of underwater and aerial robots. For example, the thermal effect of black and white color of migrating avian, such as albatrosses, shearwater, black skimmer, and sooty tern will be investigated in their skin drag through computational and experimental methods in order to be applied in painting of aerial robots’ body/wings. We will study experimentally in a water channel/wind tunnel the effects of adding riblets in drag reduction of underwater and aerial robots’ body/wing. For reduction of the shape drag of underwater/aerial robots, we will optimize and modify profiles and geometry patterned from biological aquatics and avian. We also will carry-out hydrodynamic and aerodynamic analyses of underwater and aerial robots in a water channel and wind tunnel, respectively, for laminar and turbulent flows. Moreover, drag reduction due to swarming and formation swimming of underwater robots and drones will be examined, as well.
Avian and Aquatics Color effects on Drag Reduction: In this research, the thermal effects of body color of some species of aquatics like Orcas and Dusky dolphins are investigated with respect to their swimming routes and geometric and behavioral characteristics. Considering the marine and atmospheric characteristics of these aquatics’ routes, a thermal analysis has been performed during their migration. The surrounding fluxes including the water flux, sun irradiation, and body temperature are considered in an energy balance to determine the skin temperature of the top side of the animal/organism’s body. To study the effects of color on body temperature of the aquatic species, an experiment has be carried out in the water on a flat plate with black and white color. Applying a turbulent analytical solution for heated boundary layers, it has been shown that the black color on the top of the bodies of these marine organisms is very efficient in terms of skin drag reduction. In another study the thermal effects of wing color in flight has been investigated in migrating birds like albatrosses with respect to their flight routes, migration time, and geometric and behavioral characteristics. Considering the marine and atmospheric characteristics of these flight routes, a thermal analysis of the birds’ wings has been performed during their migration, theoretically and experimentally. It has been shown that the color configuration of the migrating birds, namely black on the top side of the wings and white on the bottom side of the wings (“countershading”), results in a skin drag reduction, if compared to some other configurations, when both day and night are taken into consideration.
Aerodynamics loads variations of wings with novel heating of top surface: Applications of unmanned aerial vehicles are becoming more attainable through the increase in system efficiency. As seen in nature, birds like the albatross utilize the temperature effects resulting from their wings’ color to increase their flight efficiency. In this reserch, the effects that differences in surface temperatures of birds’ black/white wings, colored flat plates, and airfoils with heating films is investigated. Such effects are applicable to the efficiency of fixed-wing drones. Experimentally, it is observed that the surface temperature of black birds’ wings is over 50% higher than white wings under solar radiation. The application of a novel heated top surface on five airfoils results in the drag coefficient decreasing up to 60% and the lift coefficient increasing up to 70% for some airfoils in specified angles of attack compared to a non-heated top surface. This method of utilizing thermal effects can be considered as a new applicable way to increase the flight efficiency in fixed-wing unmanned aerial vehicles.
Smart Cities
Drones Applications in Smart Cities: As applications of drones are proliferating more and more, it can be expected that they will take a major role in the future of smart cities. Although several different definitions exist for the definition of the smart city, the European Platform for Intelligent Cities is defining the smart cities as the use of the new technologies like internet that is closely linked to the concept of living and user generated services. The smart cities may utilize Information and Communication Technology (ICT) solutions for different applications in urban areas. Thus, the design of the smart cities requires an integration of the ICT and other physical tools, necessitating efficient infrastructures and services at reduced costs as critical elements for the smart city. Consequently, drones and flying objects as one of these physical tools can contribute to achieving given objectives and goals for future smart cities. It can be predicted that in future, drones will be the indispensable part of the smart cities. Due to diverse applications of drones, the use of them in smart cities will continue to increase at a fast pace.
Minimum cost drone-nest matching: Development of new concepts for smart cities and applications of drones in this area impose different architecture of the drones’ stations (nests) and their placement. Drones’ stations are designed to localize and maintain the drones from any types of hazards and utilize charging mechanisms such as solar cells to recharge the drones. Increasing the number of drones in smart cities makes it harder to find the optimum station for each drone after performing its mission. In classic ordered technique, each drone returns to its preassigned station, which is shown to be not very efficient. Greedy and Kuhn-Munkres (Hungarian) algorithms are used to match the drone to the best nesting station. Three different scenarios are investigated in this study; (1) drones with the same level of energy, (2) drones with different level of energy, and (3) drones and stations with different level of energy. The results show that energy consumption reduction of 25 to 80% can be achieved by applying the Kuhn-Munkres and Greedy algorithms in drone-nest matching compared to preassigned stations. A graphical user interface is also designed to demonstrate the drone-station matching through the Kuhn-Munkres and Greedy algorithms.
Drone Stations in Airports for Inspection Using Image Processing Techniques: Drones have many applications in airports including inspection of the runway, airplanes health monitoring, fog mitigation, and bird strike avoidance. To this end, the integration of unmanned aerial systems into airports can be beneficial, which will be investigated in this project. For example, monitoring the runways at an airport using drones can be a feasible operation. In this work, a drone is used to monitor an Airport runway to find cracks and potholes that need repairing. This is done using an image processing technique to single out areas of interest. In this work, a station to dock and recharge the drones is also proposed. The nesting location, design, and safety concerns for using the drones and docking stations are studied.
