148 research outputs found
A Unified Approach to Configuration-based Dynamic Analysis of Quadcopters for Optimal Stability
A special type of rotary-wing Unmanned Aerial Vehicles (UAV), called
Quadcopter have prevailed to the civilian use for the past decade. They have
gained significant amount of attention within the UAV community for their
redundancy and ease of control, despite the fact that they fall under an
under-actuated system category. They come in a variety of configurations. The
"+" and "x" configurations were introduced first. Literature pertinent to these
two configurations is vast. However, in this paper, we define 6 additional
possible configurations for a Quadcopter that can be built under either "+" or
"x" setup. These configurations can be achieved by changing the angle that the
axis of rotation for rotors make with the main body, i.e., fuselage. This would
also change the location of the COM with respect to the propellers which can
add to the overall stability. A comprehensive dynamic model for all these
configurations is developed for the first time. The overall stability for these
configurations are addressed. In particular, it is shown that one configuration
can lead to the most statically-stable platform by adopting damping motion in
Roll/Pitch/Yaw, which is described for the first time to the best of our
knowledge.Comment: 6 page, 9 figure
Nonlinear model predictive control for hexacopter with failed rotors based on quaternions —simulations and hardware experiments—
This work applies real-time nonlinear model predictive control (NMPC) to fault-tolerant control problems of an unmanned aerial vehicle (UAV) with failed rotors. In the control problem, a hexacopter with up to three failed rotors out of the six available rotors is considered. The NMPC approach includes a quaternion-based nonlinear model of the hexacopter as well as constraints in the thrusts to consider the inherent nonlinearities of UAVs. The proposed method aims to achieve real-time optimization of the NMPC in the on-board computers without any linearization. We explore all possible scenarios in up to three rotor failures and demonstrate control designs in the NMPC for these scenarios. The simulation results indicate that by using the quaternion model, the position and attitude of a hexacopter can be controlled from a large inclined initial state with a non-zero angular velocity and falling velocity. Moreover, the results reveal that the quaternion model is superior to the Euler angle model in terms of the computation time. We also conduct hardware experiments using an actual hexacopter with a failed rotor to demonstrate the real-time NMPC optimization. The results of the simulations and hardware experiments demonstrate that the NMPC can deal with various operation conditions of a hexacopter in a unified manner, with only minor modifications in the performance index
Design and control of next-generation uavs for effectively interacting with environments
In this dissertation, the design and control of a novel multirotor for aerial manipulation is studied, with the aim of endowing the aerial vehicle with more degrees of freedom of motion and stability when interacting with the environments. Firstly, it presents an energy-efficient adaptive robust tracking control method for a class of fully actuated, thrust vectoring unmanned aerial vehicles (UAVs) with parametric uncertainties including unknown moment of inertia, mass and center of mass, which would occur in aerial maneuvering and manipulation. The effectiveness of this method is demonstrated through simulation. Secondly, a humanoid robot arm is adopted to serve as a 6-degree-of-freedom (DOF) automated flight testing platform for emulating the free flight environment of UAVs while ensuring safety. Another novel multirotor in a tilt-rotor architecture is studied and tested for coping with parametric uncertainties in aerial maneuvering and manipulation. Two pairs of rotors are mounted on two independently-controlled tilting arms placed at two sides of the vehicle in a H configuration to enhance its maneuverability and stability through an adaptive robust control method. In addition, an impedance control algorithm is deployed in the out loop that modifies the trajectory to achieve a compliant behavior in the end-effector space for aerial drilling and screwing tasks
Aerial Manipulation Using a Novel Unmanned Aerial Vehicle Cyber-Physical System
Unmanned Aerial Vehicles(UAVs) are attaining more and more maneuverability
and sensory ability as a promising teleoperation platform for intelligent
interaction with the environments. This work presents a novel
5-degree-of-freedom (DoF) unmanned aerial vehicle (UAV) cyber-physical system
for aerial manipulation. This UAV's body is capable of exerting powerful
propulsion force in the longitudinal direction, decoupling the translational
dynamics and the rotational dynamics on the longitudinal plane. A high-level
impedance control law is proposed to drive the vehicle for trajectory tracking
and interaction with the environments. In addition, a vision-based real-time
target identification and tracking method integrating a YOLO v3 real-time
object detector with feature tracking, and morphological operations is proposed
to be implemented onboard the vehicle with support of model compression
techniques to eliminate latency caused by video wireless transmission and heavy
computation burden on traditional teleoperation platforms.Comment: Newsletter of IEEE Technical Committee on Cyber-Physical System
Propeller Performance In Presence Of Freestream
This paper presents mathematical modeling for thrust force and moments generated by a propeller. In particular, the effects of freestream on propeller’s performance are investigated. We introduce some of the applications of the proposed model in modeling multi-rotor UAVs which helps to increase stability or maneuverability of the vehicle. In the end, simulation results for thrust force and moments of an example propeller in presence of a uniform freestream are presented
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