A TD-RRT* Based Real-Time Path Planning of a Nonholonomic Mobile Robot and Path Smoothening Technique Using Catmull-Rom Interpolation

Abstract

It is inevitable for a mobile robot to competently plan an optimal path from its starting, or current, location to a desired goal location. This is an insignificant task when the environment is unvarying. However, the practicable environment for the robot is hardly static, and it often has many moving obstacles. The robot may encounter one, or many, of these unknown and unforeseeable dynamic obstacles. The robot will now opt to proceed, when one of these obstacles is obstructing its path. The objective of this paper is to find a reasonable relation between parameters used in the path planning algorithm in a platform which a robot will be able to move from the start point in a dynamic environment with map and plan an optimal path to specified goal without any collision with moving and static obstacles. For this purpose, an asymptotically optimal version of Rapidly-exploring Random Tree (RRT algorithm), named RRT* is used. The algorithm is based on an incremental sampling which covers the whole space and acts fast. Moreover, this algorithm is computationally efficient, therefore it can be used in multidimensional environments.A method of dynamic replanning using TD-RRT* is presented. The robot will rectify or modify its path when unknown random moving or static snag obstructs the path. Various experimental results show the effectiveness of the proposed method which is faster than the basic RRT*, and the smooth path with the shortest distance can be obtained which satisfies the nonholonomic constraint of mobile robots.