Mitigating ground effect on mini quadcopters with model reference adaptive control

Mitigating ground effect becomes a big challenge for autonomous aerial vehicles when they are flying in close proximity to the ground. This paper aims to develop a precise model of ground effect on mini quadcopters, provide an advanced control algorithm to counter the model uncertainty and, as a result, improves the command tracking performance when the vehicle is in the ground effect region. The mathematical model of ground effect has been established through a series of experiments and validated by a flight test. The experiments show that the total thrust generated by rotors increases linearly as the vehicle gets closer to the ground, which is different from the commonly-used ground effect model for a single rotor vehicle. In addition, the model switches from a piecewise linear to a quadratic function when the rotor to rotor distance is increased. A control architecture that utilizes the model reference adaptive controller (MRAC) has also been designed, where MRAC is added to the altitude loop. The performance of the proposed control algorithm has been evaluated through a set of flight tests on a mini quadcopter platform and compared with a traditional proportional–integral–derivative (PID) controller. The results demonstrate that MRAC dramatically improves the tracking performance of altitude command and can reduce the rise time by 80 % under the ground effect

A survey on fractional order control techniques for unmanned aerial and ground vehicles

In recent years, numerous applications of science and engineering for modeling and control of unmanned aerial vehicles (UAVs) and unmanned ground vehicles (UGVs) systems based on fractional calculus have been realized. The extra fractional order derivative terms allow to optimizing the performance of the systems. The review presented in this paper focuses on the control problems of the UAVs and UGVs that have been addressed by the fractional order techniques over the last decade

Passive Compliance Control of Aerial Manipulators

This paper presents a passive compliance control for aerial manipulators to achieve stable environmental interactions. The main challenge is the absence of actuation along body-planar directions of the aerial vehicle which might be required during the interaction to preserve passivity. The controller proposed in this paper guarantees passivity of the manipulator through a proper choice of end-effector coordinates, and that of vehicle fuselage is guaranteed by exploiting time domain passivity technique. Simulation studies validate the proposed approach.Comment: IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) 201

Solar UAV for long endurance flights

The project have been done during the four months stay in Lithuania by Marc Olmo and LLibert Chamizo. The aim of the project was to obtain an Unmanned Aerial Vehicle powered by solar energy that was able to flight for as long as possible it within the limitations which are the budget, the time and the technological limitations. During the limited time, the team have been working in all the necessary phases to build a real scale and fully functional Solar UAV. This phases were the following; Theoretical Calculations, Design, Simulation, Building, Tests of the Airframe, Solar Energy Circuit Design and Building 2nd phase tests and Conclusion Obtaining. Through all the process several technical and engineering decisions have been made leading the team to obtain a fully functional 4,4m wingspan fixed wing UAV with a TOW of 5,5 Kg which is perfectly pilotable The final achievements have been a UAV capable of long endurance flight within daytime. The model achieved was able to maintain level, climb and turn perfectly using just the power gathered by the solar cells in its wing. During the development of the project the possibility of the multiday flight have been discussed leading to the conclusion that it's viable but not within the frame of this project. There have been done several tests under actual mission parameters loading the plane with the weight it would be carried during the missions that are most likely solar uav related such as mapping or surveillance. The final result have been correct and lead to an optimistic opinion about the whole Solar UAV paradigm and about the prototype modification and improvement in the near future to achieve even better results (which have been overviewed and planned in the actual report). A fatal error drove the airplane to a nosedive fall with disastrous consequences, the whole project feels and success though it's undoubtable

Three-dimensional formation flying using bifurcating potential fields

This paper describes the design of a three-dimensional formation flying guidance and control algorithm for a swarm of autonomous Unmanned Aerial Vehicles (UAVs), using the new approach of bifurcating artificial potential fields. We consider a decentralized control methodology that can create verifiable swarming patterns, which guarantee obstacle and vehicle collision avoidance. Based on a steering and repulsive potential field the algorithm supports flight that can transition between different formation patterns by way of a simple parameter change. The algorithm is applied to linear longitudinal and lateral models of a UAV. An experimental system to demonstrate formation flying is also developed to verify the validity of the proposed control system