[danshaffer]

Originally Posted by skimoose

The corners are the issue I'm raising. Try sketching out the trackball and the robot's frame and bumpers. Even after accounting for the frame under the balls arc, the back of the robot frame barely stays within an 80" cylinder at the frames corners. So if you're planning to grasp the ball you may exceed this cylinder as you reach around the ball.

my quickie CAD shows that if the ball is tangent to the front plane of your 38"x28" robot, then the front end of the ball will not fit within the 80" cylinder. there are some easy ways to get around this problem, however.