The deck that is capable of sensing the location of the CG of the person standing on it
In this prototype the deck needs to be weight sensing. The loadcell mounts needs to be incorporated into the deck. In order to make the deck weight sensing two options were considered. One was to make a double layered deck where the loadcells are in between the two decks. Or the second option was to have only one deck but place the loadcells between the deck and the truck. Second option was not feasible since the truck has to be rigidly attached to the deck. Placing a loadcell in between will either loosen the attachment of the truck to the deck or the rigidly attached truck would add stray loads to the loadcell.
Double layered deck was chosen as the better solution. One major disadvantage with double layered deck was that, it increased the thickness of the deck by more than double.
Building a curved deck, or a deck with fiberglass reinforcements were not considered necessary for testing intuitive control as it was already achieved before. The top and the bottom decks were built out of a single 3⁄4 inch plywood measuring 4 feet by 1 foot.
The deck assembly involved sandwiching the loadcells between the decks. This is a press fit arrangement. Four 8mm bolt at each corner of the deck was used to keep the assembly in place. The bolt was loosely fasted so that it does not preload the loadcells. The bolt assembly
was sealed with hot glue to prevent the bolts from coming loose due to vibrations. These bolts also have another function; they also aid the dowel pins used in the loadcell assembly to ensure that the top deck can move only vertically with respect to the bottom deck. The force that is necessary for accelerating / decelerating the rider which needs to be transferred from the bottom deck to the top deck is transferred via these four bolts. The wheel mounts and the motor mounts are attached to the lower side of the bottom deck, while the circuits, motor driver and batteries are placed on the top of the top deck for easy accessibility.