Introduction to FASTBot operations – Maze solving.

Introduction to FASTBot operations – Maze solving.

A maze is an arena with multiple pathways or tracks in which the robot has to reach a pre-defined destination from a starting point. Usually, the maze is built with walls on either side of the pathways. You can also build the maze with walls only on one side of the pathway. 

Maze solving is also used by many mobile robots. Simple maze solving is nothing but an extension of wall hugging. An advanced version of the simple maze solving is the Micromouse, which has the honour of being the most popular event in almost all the robotic competitions. 

All the applications listed in wall following are also applicable here. Maze solving robots are used to transport materials and parts in factories, warehouses and mines. They can also be used by security robots to patrol around prisons, embassies, military installations and other important buildings. In addition to all the these applications listed above, maze solving forms an integral part of indoor navigation.

Mazes can be broad classified into two types – simple and complex. The simple maze contains no closed loops. That means, a robot following the left or right walls will eventually arrive at the destination, although this may not be the quickest way. However, complex mazes contain many closed loops and the robot cannot arrive at the destination just by following a wall. A good example is the maze used in the Micromouse competitions.

Here, the FASTBot solves the simple maze by using the Keep Left strategy. The robot follows the left wall until it reaches the destination. The maze solving algorithms in FASTBot are classified based on the number of walls in the maze (i.e. whether the maze is single-walled or double-walled).

The algorithm used for single walled maze is nothing but an extension of the wall hugging algorithm. Here, the front sensor is used in addition to the left sensor. When the front sensor detects the wall, the robot is rotated clockwise. But the maze solving algorithm for double walls is a little bit different.

Maze solving for double walls.

The FASTBot is placed in between the walls, which are separated by a distance of 27 cm. If the robot is in the centre, both left and right object sensors detect the wall. If the robot is placed little closer to the left, the left object sensor will detect the wall but the right sensor will not detect the wall. Similarly, if the robot is placed little closer to the right, the right object sensor will detect the wall but the left sensor will not detect the wall. 

All the three object sensors are checked continuously. If the front object sensor detects the wall, then the robot is rotated clockwise. If both left ad right object sensors detect the wall, then the robot is moved forward. If the left sensor does not detect the wall, the robot is turned left smoothly. Otherwise, the robot is turned right smoothly.