Overview
I was a member of the UW Robomasters robotics team, and I was tasked with designing and developing a mechanism that would attach to the bottom of a drone and pick up / drop golf balls on various targets. I had a size and weight constraint, limiting my design to only one servo motor and 3D printable parts. The largest challenge throughout the process was the fact that the specifications and rules kept changing. I developed various models and designs due to the constant rule changing. I learned how to adapt and change my designs to best fit the given criteria.
Version 1
My first version was based on a 5-ball limit per flight. The idea was that the internal motor would rotate the arms away from under the golf balls, and they would simultaneously fall out and evenly hit a target on the ground - giving good coverage of the area. This design was very light and sturdy.
Version 2
My next design is based on a 10-ball limit (the rules kept changing during development). This design has two baskets which swing outwards to drop the golf balls. This design worked well, but after a week, the specifications were changed again, so a new model had to be developed. This model is based on the assumption that balls could be fed into the holder rather than having to pick them up from the ground.
Version 3
By the third version, the specifications had been finalized. This design was inspired by a trip I took to the driving range, where I saw tractors driving around picking up all of the golf balls on the field. I immediately took notes on the design and adapted it to my drone design. I noticed that the ball tractor used a mechanism which simply wedged the balls in between adjacent plates to picke them up. I then designed a system based on the same principle. This system then pushed the balls back out to drop them.
We tested this design, and it was only able to consistently pick up 4-5 balls which wasn't enough for our taste, so I started improving on the design.
We tested this design, and it was only able to consistently pick up 4-5 balls which wasn't enough for our taste, so I started improving on the design.
Version 4
My final design took the same mounting brackets as the previous iteration, as well as the successive blades, but instead of wedging the golf balls in, it activated flaps which kept the balls in place. The flaps pivot in order to let them in during collection, and release them during flight. The lobes on the timing mechanism can be adjusted so that each row gets dropped simultaneously or at various times. The design was able to pick up 10 balls, making it much more effective than the previous design.
An image of the final working model can be seen below.
An image of the final working model can be seen below.