Mobile Robots – lab6

Introduction

The goal of the assignment is to use a grid map with obstacles from the previous assignment to find a collision-free path from the current pose of the robot to a given destination.

Before the class analyze the wavefront planning method and design its implementation (optionally you may consider implementation of another planning algorithm you are familiar with, like the A-star).

Elements to consider in the algorithm

• Proper cell size for the planning algorithm.
• Transformation of the map to be used in planning.
• Path representation.
• Tests to validate the algorithm.
• Conditions for replanning the path.

Wavefront planner

1. Initialization: set the distance value of the goal cell to 0 and obstacle cells to +∞, remaining cells are undefined
2. i=0
3. while there exist undefined cells (or starting cell is not reached)
   • increment iteration number i (current distance)
   • each cell (which is a neighbour of a cell with value i-1) set to a value of the minimum of its neigbours increase by one (i)
4. Select final path from the starting cell to the goal (a series of cells with decreasing values)

Report

1. Brief description of the algorithm if different than the wavefront.
2. Description how the map was transformed to be used in planning and other decisions made in algorithm design (see the elements to be considered).
3. Tests: results and comments.
4. Attachment with the implemented code.