Robot motion planning among obstacles (Xydias, 2008)


Developing autonomous robots (either mobile or articulated robots) is a fundamental goal in modern industrial production systems and has attracted the attention of many researchers from the robotics fields. The robots must be able to accept high-level instructions of their missions and carry out these missions (at the lowest cost) by making their own decisions while moving safely in the shop floor. Such vehicles will be capable to accept high level descriptions of desired tasks and execute them without any human intervention. The theme of this thesis is the study and the solution of the motion planning problem either for one robot or for a set of robots (mobile or articulated robots). Most of the industrial applications such as pickup and delivery of products, spot-welding, multiple drilling, laser cutting and car-painting, they demand the smooth motion of the robot (or the robots) in the workspace. Each robot should be able to avoid the obstacles (static or moving) or the other robots. The complexity of the problem is depended by the geometry of the environment, the dimension of the robots’ workspace and by the robots’ kinematical constraints. Firstly, the generalization of the Bump-Surface concept for the solution of the motion planning problem in multidimensional workspaces is presented. Using the generalized Bump-Surface concept, the properties of the workspace are transferred into the surface which is constructed by B-Spline Surfaces. The robot’s path is represented by a B-Spline curve in the initial environment. The main target was the development of a methodology which is able to solve the basic motion planning problem and its generalizations. Secondly, is presented the computational time study required to construct the generalized Bump-surface depends only on the geometry and on the dimension of the environment. Furthermore, is presented the computational time required to solve the motion planning problem with constant workspace and varying number of robots. In contract with previous methods which are solved the motion planning problem for non-holonomic robots in two phases, in the present thesis is presented a solution of the problem under a global way with the capacity to handle either holonomic or non-holonomic robot (or a set of robots) moving in a dynamic 2D environment. Furthermore, is presented for a first time the solution of the combinatorial problem of motion planning and task scheduling for a set of robots.