Push recovery technical challenge

  1. Are the pushes going to be all in the same direction, or randomly from the front and back? Is the team allowed to choose? Does the referee force a choice or is it systematically defined?
  • Instead of adjusting the height so that the bottom of the bottle is at the CoM, wouldn’t it make more sense for the CoM of the bottle to line up with the CoM of the robot?
  • The method of scoring based on the ground projected distance D between the robot and the bottle unfairly favours smaller and lighter robots. What is important is the height H through which the bottle falls, not the ground projected distance, as the height determines how much energy the bottle has on impact. In high impact cases this can mean that a robot 2 times the size of another would have to absorb 7.5 times as much energy to have the same score, which is not appropriate. Having performed dynamics calculations for the whole robot-bottle system, we suggest that robots are ranked by the amount of momentum they were able to absorb, normalised by their mass and CoM height. This is a simple formula of D given the robot mass and CoM height. You can think of this as ranking the post-collision CoM velocity of the robot, normalised by the CoM height as larger robots can take proportionally larger steps with the same effort. (compare intuitively a 5cm/s CoM velocity on a DARwIn-OP and on a large adult size robot)
  1. The pushes are randomly from the front and from the back, the team is not allowed to choose. However, thinking about it, it would be good to make sure at least one of them is from the front and one is from the back. The last one would be random and the order would be random. That is at least my opinion, otherwise the chances are not too bad one team gets to do only from front or only from back.

I don’t have any opinions about the other points and I hope others join in the conversation as well

Regarding point 3, please refer to the following diagram, which hopefully intuitively explains the issue at hand, and why this really needs to be fixed.


(attempting to upload the image directly into this post was unsuccessful…)