Introduction:
Our inspiration for this project was the toy desktop basketball catapults, similar to Figure 1 below. We wanted to improve upon this idea where we could create a robot that is able to shoot consistently from various angles and locations; as well as automatically reload the shooter. This is an interesting problem to solve because we will have to design the system in a way where we are able to get an accurate trajectory and snap of the ball so that it will be able to make it into the basket. Due to having it shoot from more than one specified location it will consist of multiple iterations and design of linkages to be able to get all the desired shooting points.
Figure 1
Description of the problem:
For our project, we have decided to build a basketball shooting toy that would be able to shoot from different distances and angles. We plan to use linkage bar mechanisms that would propel the basketball from a stationary position. The base would be able to rotate fully in order to shoot the ball from different angles. The base will also move forward or backward relative to how far we want our mechanism to be from the hoop. The ball would also reload automatically after each shot. In essence, our mechanism would be able to shoot from anywhere on the court and reload balls after each shot.
Description of Proposed Mechanism:
The proposed mechanism that could solve this problem is a four-bar mechanism that has a fully rotating input linkage. The output link would slowly rotate backwards and have a ball loaded in and then release forward in a much quicker motion propelling the ball forward. Ideally the input is a constant rotational velocity allowing us to quickly shoot repetitive balls. In addition to the base mechanism, we propose the idea of one of the links being of variable length allowing us to control the exit trajectory of the ball.
Proposed Scope of Work:
For this project, we are aiming to make the whole mechanism around the size of the desktop toys that inspired us. Its minimum functionality will be the shooting motion mechanism, that will launch a ball consistently into the hoop. We would like to be able to control the speed of the mechanism to also allow it to shoot from multiple distances. Another functionality that we want to implement is an auto ball return and load, so that the machine could shoot indefinitely with no human interference.
Preliminary Design Ideas:
Our preliminary design idea is to use a 4 bar mechanism to launch the ball. We sketched an example shot trajectory that mimics the smooth motion of a jump shot. This preliminary design does not include a flick at the end of the motion to create a realistic finish to the shot, but we hope to include that in our final mechanism.
Figure 2
