Straight-line path approximation for studying Planckian-energy scattering in quantum gravity

1997 ◽  
Vol 110 (5) ◽  
pp. 459-473 ◽  
Author(s):  
Nguyen Suan Han ◽  
Eap Ponna
Keyword(s):  
Quantum Gravity ◽  
Energy Scattering ◽  
Straight Line ◽  
Path Approximation ◽  
Line Path

Vector field path following of a full-wing solar-powered Unmanned Aerial Vehicle (UAV) landing based on Dubins path: a lesson from multiple landing failures

2021 ◽  
pp. 1-30
Author(s):  
A. Guo ◽  
Z. Zhou ◽  
R. Wang ◽  
X. Zhao ◽  
X. Zhu
Keyword(s):  
Vector Field ◽  
Path Following ◽  
Endurance Performance ◽  
Electrical Energy ◽  
Lateral Control ◽  
Special Configuration ◽  
Straight Line ◽  
Lateral Distance ◽  
Solar Powered ◽  
Line Path

Abstract The full-wing solar-powered UAV has a large aspect ratio, special configuration, and excellent aerodynamic performance. This UAV converts solar energy into electrical energy for level flight and storage to improve endurance performance. The UAV only uses a differential throttle for lateral control, and the insufficient control capability during crosswind landing results in a large lateral distance bias and leads to multiple landing failures. This paper analyzes 11 landing failures and finds that a large lateral distance bias at the beginning of the approach and the coupling of base and differential throttle control is the main reason for multiple landing failures. To improve the landing performance, a heading angle-based vector field (VF) method is applied to the straight-line and orbit paths following and two novel 3D Dubins landing paths are proposed to reduce the initial lateral control bias. The results show that the straight-line path simulation exhibits similar phenomenon with the practical failure; the single helical path has the highest lateral control accuracy; the left-arc to left-arc (L-L) path avoids the saturation of the differential throttle; and both paths effectively improve the probability of successful landing.

scholarly journals Extended Kalman Filter for Bearings-Only Tracking

2019 ◽  
Vol 8 (6) ◽  
pp. 637-640 ◽  
Keyword(s):  
Kalman Filter ◽  
Extended Kalman Filter ◽  
Constant Velocity ◽  
Target Motion ◽  
Passive Mode ◽  
Crucial Issue ◽  
Straight Line ◽  
Optimal Linear ◽  
Target Motion Analysis ◽  
Line Path

Target tracking using bearings-only measurements in passive mode operation of sonar is a crucial issue of underwater tracking. Target motion in underwater scenario is analyzed using bearings-only measurements and calculating parameters like range, course and speed of the target. This is called Target Motion Analysis (TMA). TMA process is highly non-linear as the measurements chosen are nonlinearly related to the selected target state vector and the traditional, optimal linear Kalman filter will not be appropriate to use. It is presumed that the target is moving in straight line path with constant velocity, so Extended Kalman Filter (EKF) is proposed in this paper. The algorithm is simulated for several scenarios using MATLAB. Monte-Carlo runs are performed to evaluate the capability of the algorithm.

Composite finite-time straight-line path-following control of an underactuated surface vessel

2020 ◽  
Vol 357 (16) ◽  
pp. 11496-11517 ◽  
Author(s):  
Qiankang Hou ◽  
Li Ma ◽  
Shihong Ding ◽  
Xiaofei Yang ◽  
Xiangyong Chen
Keyword(s):  
Finite Time ◽  
Path Following ◽  
Path Following Control ◽  
Straight Line ◽  
Line Path ◽  
Surface Vessel
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