Position Sensing
An ultrasonic sensor was installed on the front of the robot to relay the robots distance from surrounding walls and objects to the micro-controller.
Two phototransistors were utilized to receive signals from the dispenser and hoop beacons. Both phototransistors were recessed to reduce their cones of visibility and provide a more accurate signal. The robot used the phototransistors to align with the beacons - if the left or right signal disappeared, a bang-bang control law would turn the robot in the appropriate direction to stay on course.
Crucial to the design was the ability to track the location of the drive wheels, i.e. the centroid of our robot. In order to accomplish this, two tape sensors were mounted to the bot one at the centroid of the robot and the other in the front along the major axis. Initially, the design utilized the front and middle for alignment, but it was found that the beacon alignment was more robust - thus the front tape sensor was unused.
Two phototransistors were utilized to receive signals from the dispenser and hoop beacons. Both phototransistors were recessed to reduce their cones of visibility and provide a more accurate signal. The robot used the phototransistors to align with the beacons - if the left or right signal disappeared, a bang-bang control law would turn the robot in the appropriate direction to stay on course.
Crucial to the design was the ability to track the location of the drive wheels, i.e. the centroid of our robot. In order to accomplish this, two tape sensors were mounted to the bot one at the centroid of the robot and the other in the front along the major axis. Initially, the design utilized the front and middle for alignment, but it was found that the beacon alignment was more robust - thus the front tape sensor was unused.