Tripp and Connor's Drone
Step 1: Understanding the Problem and the Constraints
Our project was to design something electronic, using the engineering design process. We had heard of quad copters as a potential project and took interest in it. Once we had established that we wanted to make a quad copter, we began researching to understand the constraints. Below are some constraints we came up with:
- Weight of the quad copter
- Size of the motors
- Length of the wires
- Size of the circuit board/battery
- Length of propellers
Step 2: Initial Sketch
We first brainstormed some ideas of what our drone could look like. We wanted to create unique design that wouldn't resemble previous designs that our class had made. Upon further research we determined that some of our ideas were not practical. We settled on an oblong X shape because the propellers had to be a certain distance away and needed to be symmetrical in some fashion.
Step 3: Initial Design
Using SolidWorks we made our oblong X shape.
Constraints we had to address in Solidworks:
- Battery Size: We measured the length and width of the battery and made the inside dimensions slightly larger so that the battery pack would fit snugly.
- Motor Size: We built each arm to have a hollow cylinder (each with a slight break in it so it can stretch) to fit the motors in.
- Physics: To improve stability and overall strength of our design, we added fillets to the arms. To decrease weight we also hollowed out the arms.
Step 4: Problems With Initial Design
Our design for the motor mounts worked because they could stretch. But it was tighter than it needed to be. To fix this so the motors fit more snug we will increase the motor mounts radius. The motor mounts were also to thin and upon first crash several broke.
When flying we realized it wasn't stable and would wobble around. We discovered that we had the propellers and motors mismatched.
Step 5: Prototype 1
For the next update to the design, we decided to focus on improving the areas around the motor. We made the areas more thick, to prevent the arms from breaking during crashes. However, during our test run, the arms broke. We attribute this to the poor printing from the 3-D printer.
During our last two flights, the propellers weren't working synchronously. To fix this we matched up our propellers and motors correctly. Having done this we thought the drone would fly properly. However, now it only had one set of propellers working at a time. This caused the drone to get some initial air and then flip out of control, and as a result broke the motor mounts. We consulted our teacher, who pointed out to us that our circuit board has a sensor that allows the motors to know what angle the drone is at. Since the sensor in the circuit board wasn't level the sensor would only power two motors, thus causing the drone to flip.
Step 6: Prototype 2
Circuit Board Issues:
This trial we hoped that by using foam tape we could keep the circuit board level, and the drone would no longer flip. We decided to reprint the same design of prototype one because we felt like the previous print didn't come out correctly. Once we were able to test it, we found that the foam tape was able to solve our main issue. However, the drone would still flip itself. (This trial the motor mounts did not break, this was because our model was printed with a higher grade plastic. Instead the motors circuits came loose from the circuit board.)
The next part of this issue was that the motors would start full throttle once we gave the drone power. We finally realized that starting the left analog stick in the center was not the correct starting position for the analog stick. Starting it in the middle was actually the position to give the motors power, and starting the analog stick pointing downwards would give the motors zero power.
Step 7: Final Product
Finally, after some re-soldering we were ready to try a third time. Our motors fit in the motor mounts snug. The plastic was thick enough and of high enough quality that if a crash happened nothing would break. Now that all of our problems were addressed we were finally able to fly our drone with success!