Two-Phase Path Planning for Robots With Six or More Joints

1990 ◽  
Vol 112 (1) ◽  
pp. 50-58 ◽  
Author(s):  
P. E. Dupont ◽  
S. Derby
Keyword(s):  
Optimal Path ◽  
Minimal Amount ◽  
World Model ◽  
Two Phase ◽  
Worst Case ◽  
Redundant Robots ◽  
Straight Line ◽  
Phase Path ◽  
Line Path ◽  
Path Modification

This paper presents a new method for planning collision-free paths for robots with any number of joints. It is particularly well suited for use with kinematically redundant robots. The algorithm is general in that it does not impose restrictions on the geometry, motion, or payload of the robot. It does not try to locate an optimal path. Instead, it attempts to locate a reasonable path while mapping a minimal amount of configuration space (c-space). The method involves iteratively modifying a connected path between the initial and goal configurations to avoid all intervening obstacles. Information from the world model is used to guide path modification. This approach is of particular value in high-dimensional cases for which exhaustive searches are impractical. In the worst case, the algorithm maps a straight-line path in c-space to the goal and the surfaces of the interfering obstacles along this path. An example for a seven-degree-of-freedom robot is included.

scholarly journals Optimal Short-Range Routing of Vessels in a Seaway

2009 ◽  
Vol 53 (03) ◽  
pp. 121-129
Author(s):  
I. S. Dolinskaya ◽  
M. Kotinis ◽  
Michael G. Parsons ◽  
R. L. Smith
Keyword(s):  
Short Range ◽  
Optimal Path ◽  
Longitudinal Direction ◽  
Wave Force ◽  
Underlying Structure ◽  
Straight Line ◽  
Calm Water ◽  
Line Path ◽  
Operational Constraints ◽  
Random Seaway

An investigation of the optimal short-range routing of a vessel in a stationary random seaway is presented. The calculations are performed not only in head seas but also in oblique waves. The evaluation of the added drag is performed by computing the time average wave force acting on the vessel in the longitudinal direction. Subsequently, the added drag is superimposed on the steady drag experienced by the ship as it advances in calm water. In this manner, the fastest path between the origin point A and the destination point B can be evaluated, taking into account operational constraints. To obtain the fastest path between two points, the underlying structure and properties of the maximum mean attainable speed are analyzed. This detailed analysis allows us to demonstrate the fastest path for the problem without any operational constraints to be a straight line. Subsequently, the solution is reevaluated for scenarios where the original optimal path violates at least one of the operability criteria considered. For that case, a fastest path is found to be a path consisting of one waypoint, that is, a two line segment path. In addition to providing a closed-form fastest-path solution for the case of no operational constraints, a bound is provided for travel time error for more general speed functions in the case where a straight line path is followed.

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.

Planning the Shortest Path in Cluttered Environments: A Review and a Planar Convex Hull-Based Approach

2019 ◽  
Vol 19 (4) ◽  
Author(s):  
Nafiseh Masoudi ◽  
Georges M. Fadel ◽  
Margaret M. Wiecek
Keyword(s):  
Path Planning ◽  
Shortest Path ◽  
Time Complexity ◽  
Optimal Path ◽  
Optimal Solution ◽  
Free Graph ◽  
Worst Case ◽  
Cluttered Environments ◽  
Planar Convex ◽  
Polyhedral Obstacles

Abstract Routing or path-planning is the problem of finding a collision-free and preferably shortest path in an environment usually scattered with polygonal or polyhedral obstacles. The geometric algorithms oftentimes tackle the problem by modeling the environment as a collision-free graph. Search algorithms such as Dijkstra’s can then be applied to find an optimal path on the created graph. Previously developed methods to construct the collision-free graph, without loss of generality, explore the entire workspace of the problem. For the single-source single-destination planning problems, this results in generating some unnecessary information that has little value and could increase the time complexity of the algorithm. In this paper, first a comprehensive review of the previous studies on the path-planning subject is presented. Next, an approach to address the planar problem based on the notion of convex hulls is introduced and its efficiency is tested on sample planar problems. The proposed algorithm focuses only on a portion of the workspace interacting with the straight line connecting the start and goal points. Hence, we are able to reduce the size of the roadmap while generating the exact globally optimal solution. Considering the worst case that all the obstacles in a planar workspace are intersecting, the algorithm yields a time complexity of O(n log(n/f)), with n being the total number of vertices and f being the number of obstacles. The computational complexity of the algorithm outperforms the previous attempts in reducing the size of the graph yet generates the exact solution.

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

scholarly journals Research and Application of Mathematical Model of Transmission Grating Signal Lissajous Figure

2018 ◽  
Vol 232 ◽  
pp. 03046
Author(s):  
Luqing Hu ◽  
Xianqing Lei ◽  
Xiaoyi Wang ◽  
Yadong Zhang ◽  
Xiaolin Zuo
Keyword(s):  
Mathematical Model ◽  
Measurement System ◽  
Electrical Signal ◽  
Two Phase ◽  
Lissajous Figure ◽  
Transmission Grating ◽  
Straight Line ◽  
Voltage Signal ◽  
Working Principle ◽  
Grating Pair

In this paper, the working principle of the grating measurement system is combined with the Fourier analysis method of Moiré fringe to establish the mathematical model of the grating signal Lissajous figure to know the quality of the grating signal intuitively. The Mathematica numerical analysis software is used to obtain the graphics of the model, and the correctness of the relationship between the parameters of the grating measurement system and the Lissajous figure equation of the grating signal is verified. The influence of the grating pair angle α on the output voltage signal and Lissajous figure of the grating measurement system is studied. The results show that the intensity of the two-phase output electrical signal decreases gradually with the increase of the deviation of the angle α of the grating pair, but the equal-amplitude of the two-phase output electrical signal does not change; Meanwhile, the shape of the grating signal Lissajous figure gradually changes from the ideal circle to the non-ideal ellipse, until a straight line with a strip slope of 135° is formed.

scholarly journals Partitioning Techniques for Built-In Self-Test Design

VLSI Design ◽  
1994 ◽  
Vol 2 (3) ◽  
pp. 185-198
Author(s):  
Chien-In Henry Chen
Keyword(s):  
Optimal Design ◽  
Design Procedure ◽  
Computationally Efficient ◽  
Two Phase ◽  
Worst Case ◽  
Hardware Overhead ◽  
Phase Cluster ◽  
Unified Algorithm ◽  
Self Test ◽  
Built In Self Test

An efficient, unified algorithm, Advanced Two-Phase Cluster Partitioning, is proposed for automated synthesis of pseudo-exhaustive test generator for Built-In Self-Test (BIST) design. A prototype of the algorithm, Two-Phase Cluster Partitioning, has been proposed and the hierarchical design procedure is computationally efficient and produces test generation circuitry with low hardware overhead. However, in certain worst case, the algorithm may generate a sub-optimal design which requires more test patterns and/or hardware overhead. In order to generate a globally optimal design, further improvement of two-phase algorithm can be achieved by expanding the design space for the formation of linear sum so that the number of test signals required for pseudo-exhaustive testing can be reduced. We demonstrate the effectiveness of our approach by presenting detailed comparisons of our results against those that would be obtained by existing techniques.

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