We set our robot to recognize an object: it's doing this by taking a snapshot of the environment and finding an object of a specified color. After finding it, it estimates how many degrees to turn in order to center the object. After it turns, it checks whether the object is in the center of image or not, then if necessary it turns again to adjust the position of the object in the image. When the object is centered, the robot drives forward to it.
Our first idea involved that the boxes should be placed on a table, in order to be lifted. However, most often, in practical circumstances the boxes should be lifted from the floor and not from a shelf, or table. Thereby, we decided to rebuild the fork to meet this requirement.
Eximius is a robot that moves boxes (wares) from one place to another and organizes them in a user-defined manner. The boxes will be placed on pallets. In order to solve this task, Eximius does the following steps:
- Detects the wares zone.
- Drives to the wares zone.
- Identifies which box to lift (using bar-codes placed on boxes)
- Lifts the fork at the height where the box is placed.
- Enters fork in the space below the pallet on which the box is placed.
- Takes the box from the wares zone (without dropping it)
- Drives to the zone where the box has to be placed (destination zone)
- Places the box in the zone chosen by user.
Eximius is built on an iRobot platform. It uses a fork made from an aluminum rod, 2 bumpers (one for
box detection, the other for detecting the fork's zero level), 2 distance sensors for measuring distances to the wares zone / destination zone, a web-cam for box identification and a NXT Brick to communicate with the sensors, the web-cam and the fork lifting gear.
The part that supports the fork, as well as the parts that holds the two axis in place (colored in purple) were created using a 3D printer.
Lifting the box...
When the robot arrives in wares zone (after identifying the box to lift), the fork lifting gear rotates the fork lifting axis. When the fork arrives at the same level with the box, the robot drives slowly forward until the box detection bumper is triggered. At the same time, the robot lifts the box and drives backwards a little bit, then it turns 180 degrees, with the fork facing towards the destination zone.
In the destination zone, these steps are resumed, but in reverse order (this time identifying the place where the box has to be put).