Chair Gripping Algorithm

Assumptions

• A chair is in the camera’s view.
• Both colors are on the chair.
• The right side of the chair is cleared (this will be fixed, time permitting).
• The robot is within 900mm of the chair after Object Recognition module executes.

Algorithm Description

The rafsGripChair module starts once the Object Recognition module has finished execution. Two conditions can be made at this point: the chair leg is directly in front, or it is not. The very first thing that is done in this module is to center the robot with the middle of the chair (the pink area). Once this is done, if the leg is aligned along the y-axis within a given range (10 mm) of the middle of the chair, it will approach the chair until it is within a specified gripping distance. An example of an aligned chair is as follows:

At this point, it closes the gripper and sets the camera back to the original orientation, and completes. The complicated part comes in when the leg is not aligned correctly.

If the leg is not aligned within a given range (10 mm) of the middle of the chair (or pink), the robot will turn 90 degrees, and pans the camera angle to face back toward the chair. It will then drive in a turning fashion to maneuver around the chair, on the right side. Once the camera notices that the two colors are lined up along the y-axis, it stops moving around the chair, and turns to face the chair. The camera then gets reset to be facing forward. Once this condition is met, the robot can continue to approach and grab the chair. An example of a chair not aligned correctly is as follows:

Other notes about the module:

It is important to note that the camera gets the center X, Y values for the color based on the camera’s 2-dimensional view, in other words, whatever is in the camera’s view has an X, Y coordinate value. The camera’s X, Y coordinates are in no way related to the robots X, Y coordinates.