scholarly journals Time-varying Formation Dynamics Modeling and Constrained Trajectory Optimization of Multi-quadrotor UAVs

2021 ◽  
Author(s):  
Xi Li ◽  
Guoyuan Qi ◽  
Limin Zhang
Keyword(s):  
Rigid Body ◽  
Trajectory Optimization ◽  
Pseudospectral Method ◽  
Time Varying ◽  
Body Structure ◽  
Dynamics Modeling ◽  
Quadrotor Uav ◽  
Quadrotor Uavs ◽  
Turning Radius ◽  
Time Required

Abstract The formation of multiple quadrotor UAVs with long navigation will encounter many flight constraints, so it is necessary to change the formation to avoid these constraints. In this paper, Voronoi graph theory is used to treat UAVs formation as a rigid body. The rigid body structure can be changed by changing the formation before different constraints, after passing constraints the rigid body structure remains the formation unchanged or form into the prescribed formation. The time-varying model is established to facilitate the use of optimization. Based on Gauss pseudospectral method (GPM), the path optimization of a single quadrotor UAV is carried out. The followed UAVs in formation are treated as constraints. The constraints of maximum turning radius and formation transformation time of other UAVs are considered in the optimization process. The minimum time required for formation transformation is optimized to solve the transformation optimization, and the performance index of trajectory optimization is to minimize the energy consumed by the leader quadrotor UAV within the specified time. Finally, the simulation proves the method proposed in this paper.

Geometric PID Control for Almost-Global Stabilization of a Quadrotor With Parameter Error and Constant Disturbances

2014 ◽  
Author(s):  
D. H. S. Maithripala ◽  
Jordan M. Berg
Keyword(s):  
Rigid Body ◽  
Pid Control ◽  
Parameter Uncertainty ◽  
Body Motion ◽  
Three Dimensions ◽  
Euler Angles ◽  
Time Varying ◽  
Global Stabilization ◽  
Quadrotor Uav ◽  
Integral Action

Intrinsic controllers are invariant under the coordinates used for their representation. In the case of rigid-body motion in two and three dimensions, the intrinsic approach eliminates problems with singularity or over-parametrization that may occur in specific choices such as Euler angles or quaternions. Intrinsic PD controllers that combine almost-global stabilization with a familiar and intuitive PD design framework have been known for several years. In this paper we show how intrinsic integral action may be added to intrinsic PD control. We apply the result to stabilize the attitude of a quadrotor UAV model, and demonstrate in simulation that performance is significantly improved in the presence of parameter uncertainty and constant disturbance forces. We also consider the effect of bounded, time-varying, disturbances.

A method for autonomous collision-free navigation of a quadrotor UAV in unknown tunnel-like environments

Robotica ◽  
2021 ◽  
pp. 1-27
Author(s):  
Taha Elmokadem ◽  
Andrey V. Savkin
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Autonomous Underwater Vehicles ◽  
Three Dimensional ◽  
Underwater Vehicles ◽  
Practical Implementation ◽  
Challenging Problem ◽  
Quadrotor Uav ◽  
Navigation Algorithm ◽  
Aerial Vehicles ◽  
Quadrotor Uavs

Abstract Unmanned aerial vehicles (UAVs) have become essential tools for exploring, mapping and inspection of unknown three-dimensional (3D) tunnel-like environments which is a very challenging problem. A computationally light navigation algorithm is developed in this paper for quadrotor UAVs to autonomously guide the vehicle through such environments. It uses sensors observations to safely guide the UAV along the tunnel axis while avoiding collisions with its walls. The approach is evaluated using several computer simulations with realistic sensing models and practical implementation with a quadrotor UAV. The proposed method is also applicable to other UAV types and autonomous underwater vehicles.

scholarly journals Trajectory optimization of UAV based on Hp-adaptive Radau pseudospectral method

2021 ◽  
Vol 0 (0) ◽  
pp. 0
Author(s):  
Yi Cui ◽  
Xintong Fang ◽  
Gaoqi Liu ◽  
Bin Li
Keyword(s):  
Trajectory Planning ◽  
Trajectory Optimization ◽  
Optimization Problem ◽  
Tracking Error ◽  
Pseudospectral Method ◽  
Planning Problem ◽  
A Algorithm ◽  
Planning Scheme ◽  
Path Search ◽  
Simulation Results

<p style='text-indent:20px;'>Unmanned Aerial Vehicles (UAVs) have been extensively studied to complete the missions in recent years. The UAV trajectory planning is an important area. Different from the commonly used methods based on path search, which are difficult to consider the UAV state and dynamics constraints, so that the planned trajectory cannot be tracked completely. The UAV trajectory planning problem is considered as an optimization problem for research, considering the dynamics constraints of the UAV and the terrain obstacle constraints during flight. An hp-adaptive Radau pseudospectral method based UAV trajectory planning scheme is proposed by taking the UAV dynamics into account. Numerical experiments are carried out to show the effectiveness and superior of the proposed method. Simulation results show that the proposed method outperform the well-known RRT* and A* algorithm in terms of tracking error.</p>

scholarly journals Disc starts: the pectoral disc of stingrays promotes omnidirectional fast starts across the substrate

2019 ◽  
Vol 97 (7) ◽  
pp. 597-605 ◽  
Author(s):  
S.G. Seamone ◽  
T.M. McCaffrey ◽  
D.A. Syme
Keyword(s):  
Rigid Body ◽  
The Body ◽  
Similar Performance ◽  
Yaw Rate ◽  
Benthic Environment ◽  
Fast Start ◽  
Escape Responses ◽  
Turning Radius ◽  
Longitudinal Flexibility ◽  
Translational Speed

We explored how the flattened and rounded pectoral disc of the ocellate river stingray (Potamotrygon motoro (Müller and Henle, 1841)) enables them to use the benthic plane during fast-start escape. Escape responses were elicited via prodding different locations around the pectoral disc and were recorded using video. Modulation of pectoral-fin movements that power swimming enabled omnidirectional escape across the substrate, with similar performance in all directions of escape. Hence, translation of the body did not necessarily have to follow the orientation of the head, overcoming the constraint of a rigid body axis. An increase in prod speed was associated with an increase in initial translational speed and acceleration away from the prod. As prod location shifted towards the snout, yaw rotation increased, eventually reorienting the fish into a forward swimming position away from the prod. Furthermore, P. motoro yawed with essentially zero turning radius, allowing reorientation of the head with simultaneous rapid translation away from the prod, and yaw rate during escape was substantially greater than reported during routine swimming for stingrays. We conclude that stingrays employ a distinctive approach to escape along the substrate, which we have termed disc starts, that results in effective manoeuvrability across the benthic environment despite limited longitudinal flexibility of the body and that challenges the concept of manoeuvrability typically used for fishes.

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