Again in the RePlay (2021) season, another mission required gently lifting a platform, to have a small cube sitting on it fall inside a certain area, and then, dropping more cubes (which would be carried by the robot). We combined these missions, by adding a moveable hook to a small “dumpster”, all attached to the up-and-down arm (moved with the rack-and-pinion).
The dumpster flips when the robot simply drives forward into the fixed arm of the platform structure. This is an example of a partially-passive mechanism, where movement is achieved by pressing against some other existing object, without the need of action with a specific motor — the robot is only partially driving into the other object.