"The Little Things" - Helpful hints for all

[KrazyCarl92]

Originally Posted by Samwaldo

Why?

While I can't speak for Bryan, I can say that the reason our team would like to do this is that lower bumpers are advantageous for CoG reasons, pushing match reasons, and avoiding tipping.

The lower CoG is quite obvious. However, less obvious are the pushing match advantages. During a pushing match, normal force is quite often transferred between the robots. Consider 2 robots with equal weight and traction capabilities, both at 145 lbs with bumpers and battery but different bumper heights. When they engage in a pushing match, it is possible that the one with higher bumpers may transfer some of its weight to the robot with lower bumpers. Now you may have the high bumper robot with 130 lbs of normal force available to "turn into" tractive force, while the low bumper robot might have 160 lbs of normal force to "turn into" tractive force. This means the robot with lower bumpers could have more pushing force due to the increased normal force on its wheels. The ground still supports the total weight of both robots, but not necessarily equally at all points. In addition the robot with higher bumpers may tend to get up-ended in this situation.

It can also help in avoiding tipping. If the bumpers are lower, they will "catch" the robot as it tips more quickly than if they are higher up. I have also seen robots tip such that their support polygon is the frame and the bumpers, which is way less probable with lower bumpers.