Improving Lateral Safety Distance-Based on Feature Detection and Probabilistic Roadmaps for Unmanned Vehicle Path Planning

Most of the existing path-planning algorithms do not consider lateral safe distance requirements in practical applications. Hence, in this study, a new path point selection algorithm is proposed for path planning. The algorithm first used the Harris and Line Segment Detector(LSD) algorithms to detect and obtain the corner and edge information of obstacles. A vertical line was provided to the edge of the surrounding obstacles along each corner successively. In this process, the narrow impassable area in the map was filtered and removed by setting a safety threshold, and the foot of the vertical coordinates were simultaneously obtained. The corresponding midpoint coordinates were solved by using the corner coordinates and the foot of the corresponding perpendicular coordinates. The midpoint coordinates were used as candidate points to generate path points. These candidate points are screened and relaxed using the Probabilistic Roadmaps(PRM) algorithm to obtain the series of path points required. Finally, the path was planned according to these path points and smoothed using the Quadratic polynomial interpolation method(QPMI). Through simulation experiments, the method proposed in this study can solve a unique path without randomness under given conditions, and the probability of a collision in practical applications was reduced.

Exergy analysis of a three-spool turboprop engine during the flight of a cargo aircraft

Purpose This study aims to introduce exergy analysis of a three-spool turboprop engine during the complete flight. Design/methodology/approach In this study, a flight scenario of the aircraft is assumed. Operating parameters of the aircraft and its engine are modelled based on the assumed flight scenario with the aid of a genuine code. And then performance analysis of the engine is performed for each flight path point with the aid of exergy. Findings At the end of the study, major exergy parameters of the engine are calculated during the complete flight of a cargo aircraft three-spool turboprop engine. Practical implications Findings of the study may be beneficial for industry and practitioners to improve performance of the evaluated engine. Originality/value To the best of authors’ knowledge, this paper presented the exergy analysis of a three-spool turboprop engine during the complete flight for the first time. It was shown how the exergy destruction rate depends on the altitude and manoeuvre.

Development of Scanning Line Tool Path Generation Algorithm Using Boundary Position Information of Approximate Polyhedron of Complex Molds

In the manufacturing industry, molds are required for mass production operations, and the industry’s recent small lot, multi-product production systems call for such molds to be made by NC machine tools in short periods of time. The tool path point coordinates of NC machine tools are derived by geometric computations, which are used in turn to derive the polyhedron-approximated mold surface and the contact positions of the tool. In the conventional method, however, placing surplus tool path points on the planar section makes it difficult to acquire the boundary position coordinate values in the vicinity of the boundaries of the polyhedrons that constitute the curved surface, resulting in errors in the path point coordinates for the polyhedron-approximated shape of the mold surface. In this study, therefore, we have developed CAM algorithms that can reduce the tool path errors and suppress the number of tool path points by not deriving the path point coordinates in the linearly approximated section. This is done by using the boundary information of the approximate polyhedrons that constitute the concave section of the mold model.

Path planning method based on discontinuous grid partition algorithm of point cloud for in situ printing

Purpose Path planning is an important part of three-dimensional (3D) printing data processing technology. This study aims to propose a new path planning method based on a discontinuous grid partition algorithm of point cloud for in situ printing. Design/methodology/approach Three types of parameters (i.e. structural, process and path interruption parameters) were designed to establish the algorithm model with the path error and the computation amount as the dependent variables. The path error (i.e. boundary error and internal error) was further studied and the influence of each parameter on the path point density was analyzed quantitatively. The feasibility of this method was verified by skin in situ printing experiments. Findings Path point density was positively correlated with Grid_size and negatively related to other parameters. Point_space, Sparsity and Line_space had greater influence on path point density than Indentation and Grid_size. In skin in situ printing experiment, two layers of orthogonal printing path were generated, and the material was printed accurately in the defect, which proved the feasibility of this method. Originality/value This study proposed a new path planning method that converted 3D point cloud data to a printing path directly, providing a new path planning solution for in situ printing. The discontinuous grid partition algorithm achieved controllability of the path planning accuracy and computation amount that could be applied to different processes.

Position deceptive tracking controller and parameters analysis via error characteristics for unmanned aerial vehicle

Covert Global Navigation Satellite System spoofer, called position deceptive tracking controller for unmanned aerial vehicle, is studied via analyzing the error characteristics in this article. Specifically, the following topics are discussed: (1) design the position deceptive tracking controller to make unmanned aerial vehicle deviate from the original path and follow up the spoofed new path point by point, and (2) analyze the related parameters by exploring the characteristics of the initial estimated state errors. Simulation results show the designed controller can realize the position offset of unmanned aerial vehicle unknowingly. What’s more, it can eliminate the initial state errors by selecting appropriate parameters.

Simplified Path Programming for Industrial Robots on the Basis of Path Point Projection by a Laser Source

This paper describes the concept and implementation of a hybrid programming method for robots, which absolves working people from the specific expertise that is required for the conventional programming of robots. The method is based on a provided path point, which is presented by laser projection. The projected path points are detected and approached by the robot. By linking the path points and entering the path and transfer parameters on a tablet computer the path is programmed in a simple and easy understandable way. Afterwards the path can be executed and the produced robot program can get exported. In this way, not only the circle of people who can program a robot will be extended, but also the safety of the people improves because nobody has to stay in the immediate vicinity of the robot, while programming it.