In my project, I've successfully analyzed the arena and have detected the obstacles using an overhead webcam. I also have computed the shortest path. The path data is transmitted to the robot via Zigbee, based on which it moves to its destination.

The problem is: My robot is not taking accurate turns which would cause error in the rest of path it follows.

Could anyone please suggest any methods/techniques for feedback from the robot so as the path is corrected and the robot follows the original path computed without any deviation? (Basically a tracking mechanism to avoid deviation from the original computed path)

  • $\begingroup$ You should describe more about your setup. for example other sensors, control methods you are using for motion of robot $\endgroup$ – nikhil Feb 9 '15 at 16:27
  • $\begingroup$ I'm using the position encoders. Though these don't work perfectly at right angled turns. I have placed two colored stickers on robot to detect its orientation from the overhead camera. It's all based on image processing, so I wont be using any sensors in that case. I'll be sending movements commands to the robot via Zigbee. $\endgroup$ – Heethesh Feb 10 '15 at 13:57

You should feedback on position and heading using the information from the webcam overhead.

So you have an list of cells that make up the path that you would like to travel in the order that you would like them visited. Give each cell a property 'traveled' with an initial value of false. Give the robot some slow constant speed with a desired heading that points it to the next untraveled cell. Once the robot gets withing some distance of the cell, mark the cell as traveled and move on to the next one. As long as the robot is moving slow enough compared to the rate you are sending commands, this should get you through the maze.

Good luck!

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  • $\begingroup$ Yes! But how to do that is what I wanted to know... $\endgroup$ – Heethesh Feb 11 '15 at 15:11
  • $\begingroup$ what are you using for path planning? Do you know the vehicle's current position and orientation? $\endgroup$ – holmeski Feb 14 '15 at 2:36
  • $\begingroup$ Yes the position and orientation is known. I'm converting my arena into a grid and using A* to find the path. Path is in the format of a sequence of coordinates. The position of the bot is also known in terms of coordinates from this grid. $\endgroup$ – Heethesh Feb 14 '15 at 16:51

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