The past 2 months have been rough for our team. We have been trying our best to create a successful robot; however, we have been running into several issues. The above picture is a picture at the Hedrick Middle School scrimage in Lewisville, Texas, an event made for FTC teams to allow them to test out their robots and determine what needs to improved with the robot. By the time of this scrimmage, we had made great progress on the robot. We had completed the base as well as mounted a carwash mechanism led into with a ramp. Pieces of the ramp were 3-D printed using PTC Creo as shown below.
Before the start of competition, our team realized that we forgot our catapult launcher at our workstations at home. Therefore, we frantically attempted to build another launcher with the limited number of tools we could find. We then mounted this to the robot and attempted to create a way for the ball to lead into the catapult.
We entered our first round which was a great learning experience as the controls on the robot were inverted, making the robot incredibly hard to drive. We fixed this for the second round; however, we ran into another problem in the following rounds. One of the main issues we had was that the catapult consistently fell apart after a few launches. Also, our car wash was not strong enough to push the ball up the carboard ramp.
We took the learning experiences from the scrimmage and the past few meeting to end with the following at the end of today's practice.
We realized that the problem with the carwash was not the speed at which it turned but rather the amount of traction it had. Because the carwash was made of zip-ties, there is a very low frictional force between the carwash and the ball as the ball is plactic as well. We fixed this issue by duck-taping small pieces of rubber bands to the ends of each ziptie. This helped in ensure that the ball would move in properly through the carwash. We decided to strip the carboard ramp idea and to develop a polycarbonte ramp down the line. We were also successful in attaching a servo to the robot, something we are planning on using to hit the beacons during autonomous using the color sensor on the android phone. Finally, the team had a debate on whether we should continue using the catapult or use a flywheel design, an idea proposed by our team captian(Austin). The flywheel could potentially be more beneficial as it allows for faster shooting and more acuracy. The idea is that because the wheels are on a polycarbonate ramp, the distance between the wheels would be less than the diameter of the ball. By doing this, when the ball travels through the wheels, the wheels will provide more force onto the ball therfore propelling it further. Also, rubber bands were placed on the wheels to provide extra traction to the ball, adding to the velocity of the ball. This is demonstrated in the video below.
Ultimately, our team has made great progress during the past two months. We hope we can complete a successful robot by the time of our next scrimmage on 12/18/16.
Written by: Abhijit Bhattaru