The bridge model attached tread to the PVC pipe. They first drilled two holes in each tread. They drilled corresponding holes in the PVC pipe. Then, they attached the tread to the pipe using a riveter. The purpose of this was to build the roller to ease the totes in the bridge model.
The second group investigated the possibility of having a two-pronged arm where one prong adjusts to the width of the bin. They used a spring-loaded pneumatic actuator. For the rest of the time, they did calculations.
The third group explored the grabber from one side of the bin or tote possibility. They had a one-sided hook but decided to have two prongs with rubber treads attached to them so that they could create more friction and have more contact points.