We were tasked to design a robotic gripper capable of picking up and holding a two pound ball. The ball had a low friction surface finish and an unknown center of mass position. Once the gripper engaged and picked up the ball, the arm that the gripper was mounted to was swung. During the swing, the gripper had to hold the ball in place and once the swinging motion was stopped, the ball was to be released back to its original stand.

The final gripper shown above, utilized a pulley system to engage and grip the ball. The pulley system was designed such that it only engaged the ball when forward rotation of the motors shaft was applied. When the motors shaft was rotated in the opposite direction, a lock nut mechanism stalled the motor such that the pulley system would not engage the gripper. This was done such that when the motor was stalled using the lock nut mechanism, the gripper could return to a relaxed state and release the ball. Furthermore, to test the gripper, the following procedure was used:

1. Gripper and arm assembly was placed over the ball.
2. The pulley system was engaged.
3. Once gripper bumpers made contact with the ball, the motor stalled and gripper picked up and held the ball in place.
4. Ball stand (not shown) was then removed from the test rig.
5. The arm was swung around the test rig.
6. Once the arm came to rest, the ball stand was placed back to position.
7. Finally , the motor was driven backwards to place the ball back on the stand.

In the end, the gripper successfully engaged the ball using the test outlined above.