Introduction      Mechanical System      Electrical System      Strategies
 

Our strategy of collecting the most balls while maintaining a good defensive position led us to design Kiff, a simple ball collector that would also act as a blockade to opponents attempting to score. The path of Brannigan and Kiff protected both lanes to the goal. By programming different ROMs, we were able to create several different variations of the paths shown. Below, we investigate the building of a dumb agent, our method of ball collection, and the issues encountered with both.

The main design criterion for Kiff was that he had to be small enough that Brannigan could carry him without exceeding size and weight restrictions. This limited what we could do with him. Kiff was essentially designed as a box with two compartments: space for ball collection and a space for drive mechanism. Due to the nature of the path Kiff would be running, the ball collection area was chosen to be on the right side. The drive mechanism was a salvaged gearbox (10:1 ratio) with a foam padded wheel and an RC motor (Monster Horsepower Jr.). We went with this system because we could build it quickly and spend more time on the main robot. However, the single wheel mechanism presented some difficulty in control. But since Kiff would be a "dummy agent" we were not to concerned about this. The robot veered to the right which was acceptable because the wall would be able to guide Kiff as the robot bumps into it. If we wanted more accurate motion we could have created a system in which there are two driving wheels.

Our original plan for ball collection involved initially collecting balls in an open area in the front of the robot. Naturally these balls would congregate to the rear of the bin since the robot continuously moves forward. With the balls against the rear wall, two parallel plates rigidly connected would come down from above, grab the balls, and go back up. This process is shown in the above illustration. On the way up the balls would be forced out of the plates by a bar acting as a stopper and fall into a bin. The path to the bin would be set by a sprung lever which would be pushed open when the plates are going down and close after the plates have reached a certain height. The holding bin would be sloped so that all the golf balls would be against a doorway that would remain closed until the robot got to the goal. Once there, a solenoid would be able to open the door and all the balls would be able to fall into the goal. This is a rather complicated design that had many challenges. In order to make sure that the plates would be able to grab the balls we attached brillo pads to the bottom edges. This surface had enough surface roughness so that the balls were easily held as they were going up. Another problem that arose was that we need a way to drive the motion of the plates. A rack and pinion method was considered to be too complicated and time-consuming to pursue. A cable/pulley system was considered to be to unreliable in giving us the motion we wanted. We finally decided that a crankshaft system would provide us with the most reliable motion with the least amount of control issues. Unfortunately, we did not have enough time to implement these ideas. Instead we concentrated on capturing balls. The main concern with capture was to make sure that the balls stayed under the robot when the robot stopped. To do this we used a brass rod suspended by string that could only swing one way due to well placed tabs. The bar would be light enough that the golf ball could swing it out of the way on the way in. The bar would also be rigid enough that when the a ball tried to get out the tabs could prevent the bar from swinging out. With this design it was important that nothing (such as nuts or bolt heads) impeded the free swing of the bar when the ball went in. The bar worked best when it was at a height at about the middle of the golf ball. That way the golf ball could not go under the bar and yet it could still get in easily.

Introduction      Mechanical System      Electrical System      Strategies