I have been doing some modifications to the front of Cherub as it has problems moving with another robot "on board."
The reason is the front of the robot is weighed down too much and the front plough digs in the arena floor and stops Cherub from moving.
If I make the front higher then I would not get under anything and if I leave it I won't be able to move to drop the robots that has been caught into the pit!

The solution to this is to have retractable front wheels.

I have fitted to the lifting shaft, a cam that engages the follower that is attached to another set of wheels under the front of the robot.
When the lift arm is horizontal the cam is disengaged and the robot is on it's castors as normal, and when the arms are vertical the cam is fully engaged lifting the front of the robot about 8-10mm off the arena floor!

This should be enough to release the front of the robot and make it possible to move with the extra weight.

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