Citation: Psotka, M.; Duchoˇn, F.;
Roman, M.; Michal, T.; Michal, D.
Global Path Planning Method Based
on a Modification of the Wavefront
Algorithm for Ground Mobile Robots.
Robotics 2023, 12, 25. https://
doi.org/10.3390/robotics12010025
Academic Editors: Luis Payá, Oscar
Reinoso García and Helder
Jesus Araújo
Received: 20 January 2023
Revised: 2 February 2023
Accepted: 6 February 2023
Published: 8 February 2023
Copyright: © 2023 by the authors.
Licensee MDPI, Basel, Switzerland.
This article is an open access article
distributed under the terms and
conditions of the Creative Commons
Attribution (CC BY) license (https://
creativecommons.org/licenses/by/
4.0/).
Article
Global Path Planning Method Based on a Modification of the
Wavefront Algorithm for Ground Mobile Robots
Martin Psotka
1
, František Ducho ˇn
1,
* , Mykhailyshyn Roman
2,3
, Tölgyessy Michal
1
and Dobiš Michal
1
1
Institute of Robotics and Cybernetics, Faculty of Electrical Engineering and Information Technology,
Slovak University of Technology, 811 07 Bratislava, Slovakia
2
Texas Robotics, College of Natural Sciences and the Cockrell School of Engineering, The University of Texas at
Austin, Austin, TX 78712, USA
3
Department of Automation of Technological Processes and Manufacturing, Ternopil Ivan Puluj National
Technical University, 46001 Ternopil, Ukraine
* Correspondence: frantisek.duchon@stuba.sk; Tel.: +421-915-719-462
Abstract:
This article is focused on the problematics of path planning, which means finding the
optimal path between two points in a known environment with obstacles. The proposed path-
planning method uses the wavefront algorithm, and two modifications are implemented and verified.
The first modification is the removal of redundant waypoints. The first modification is applied because
the wavefront algorithm generates redundant waypoints. These waypoints cause unnecessary
changes in the direction of movement. The second one is smoothing the generated trajectory using
B-spline curves. The reason for applying the second modification is that trajectory generated by the
wavefront algorithm is in the form of the polyline, which is inadequate in terms of the smoothness
of the robot’s motion. The verification of the proposed method is performed in environments with
different densities of obstacles compared with standard Dijkstra’s and A* algorithms.
Keywords: global path planning; wavefront algorithm; B-spline curves; ROS; ground mobile robot
1. Introduction
For the safe movement of a mobile robot in the environment, it is necessary to perform
two basic activities—localization and navigation. Localization is performed using an
environment map and suitable sensors, and SLAM [
1
,
2
] is primarily concerned with this
issue. The localization, therefore, determines the robot’s position in the environment.
For the collision-free movement of the robot, the so-called reactive navigation is used.
This navigation must react fast enough concerning objects in the environment and the
robot’s activity. Reactive navigation usually uses only current measurements from sensors
and is also called local navigation [
3
]. The robot’s path planning (i.e., global navigation) is
implemented in a known or partially known environment with a predetermined goal. This
article focuses on the issue of path planning.
The optimality of the planned path cannot be determined in general [
4
]. The type of
robot chassis used, dimensions, dynamic limitations, etc., are essential. It is also because
mobile robots occur in various applications and environments. It depends on these facts
and application requirements which path characteristics are crucial and to what extent. The
following features are often considered essential in path-planning algorithms:
1.
The computational complexity also depends on the computational power available to
the robot. Currently, some mobile devices are already performing such computing
power that in smaller environments and with slower motion, the need for both levels
of navigation (global and local) disappear.
2.
In some cases, the shortest possible path may be preferred, while in other cases, a
slightly longer path may be suitable because it has better properties according to
another criterion.
Robotics 2023, 12, 25. https://doi.org/10.3390/robotics12010025 https://www.mdpi.com/journal/robotics
