User:Kcarpent7117/enes100/quadp2

These are descriptions of my work on the Quadcopter project.

Week0 Activities
Since I was transitioning into another portion of the same project, I continued what I was doing for week four of the previous section. I began work on constructing the actual balance itself, as well as making small adjustments to the design of the balance from the previous weeks.

My First Task
Now that the U joints were complete from the previous' week's work, I will work on putting all the pieces of the balance together so we can start testing with the adruino.

Week1 Activities
This week, I constructed the horizontal support for the motors, created a rudimentary stand, and broke the gimbal joint from the previous weeks' work.

Week1 Narrative
The previous design that we were planning on using for the balance consisted of a long arm with a counterbalance. Although this would be a nice design for testing a finalized quadcopter with programming to suit every axis, this balance needs to work with software that is only tuned to work for a single axis of rotation. The new design is relatively simple; Rather than hanging below a shaft, the motor beam rests on top of the gimbal joint with a vertical support underneath. The only components on the balance beam would be the two motors, escs, and the accelerometer; The arduino and any other components we might need will be attached to the vertical shaft of the balance.

The horizontal beam is a 1/2"x2"x15" piece of balsa wood. I drilled a 1" hole in the middle of the beam and slid the ball bearing inside, such that it fit snugly without any glue. For the vertical beam, I made a wooden plug for a 3/4" piece of PVC pipe with a 1/2" hole drilled in the middle, just large enough for the end of the gimbal joint to fit tightly. Unfortunately, during this process the stress put upon the gimbal joint was too much, and the method I used to reattach parts of the gimbal joint failed.

My Second Task
I need to either find a way to fix the old gimbal joint, or devise a method to create a new one.

Week2 Activities
This week, I started working on a new method to make a gimbal joint.

Week2 Narrative
The focal point of the gimbal joint I was using is the metal ball housed within the plastic shafts that hold it in place. The plastic holders used on the joint were broken beyond repair, so my goal was to find a good replacement for the brackets to hold the ball. At first, I attempted to create a wooden replica of the current plastic brackets. The wooden brackets would have a split down the central shaft, so that the ball could be inserted and removed easily. The hole for the small arms of the metal ball to go through would need to be about 0.02" in diameter, so I drilled a small hole in the wood first so I'd be able to saw around it to make the brackets. As I was sawing the wood using a jewelers saw into the basic shape of the bracket, the wood was flaking off in sheets, despite me selecting a piece of wood that didn't have a prominent grain to it. I continued to saw anyways, but in the end, I decided the wood would be too weak of a material to create a good gimbal joint.

My Third task
I need to think of a new idea for creating a new joint.

Week3 Activities
I begun to work on a new design for the gimbal joint brackets, and tested out some aspects of the current software/accelerometer on the arduino.

Week3 Narrative
I switched to using aluminum as the brackets, which provided two distinct advantages: fabrication of the joint would be much easier, and inserting and removing the metal ball at the center of the gimbal joint would be much faster than with a wooden or plastic joint. However, using aluminum for the sides of the brackets is a risk, since the aluminum is more prone to warp under the stress of the motors on the balance. Once the balance is complete, the rigidity of the joint will need to be tested. I fabricated the joint by snipping out a thin strip of aluminum, bending it about a piece of plywood about the same width of the metal ball, and then drilling a hole through the metal piece using a bit that's slightly larger than the poles on the metal ball. After filing down the sides of each bracket a little bit, we inserted the ball into the two holders and had the main piece of the gimbal joint.

My Fourth task
I need to figure out a way to attach the gimbal joint to the bearing in the motor balance and the support shaft, as well as testing the current quadcopter software.

Summary of actual work over fourth weekend
I conducted some tests using the current quadcopter software and serialchart.

Week4 Narrative
I tested the software of the quadcopter using Serialchart by Starlino. This program was made by the same coder who created the majority of the code for the PID controller of the accelerometer, and it displays data generated by the ardunio using a graph. A tutorial of how to connect the ardunio to serialchart is below. My results from the serialchart output indicated that there was a discrepancy between the input of the accelerometer and the output from the PID controller software. This was most likely due to the discrepancy between the sensitivities for the IMU; the program was tuned to use an IMU created by the coder, and I am using a sparkfun IMU with different sensitivities for the accelerometer and the gyroscope. This information can be found here for the IMU that we are using, under documentation for the ADXL335 accelerometer and the IDG500 gyroscope.

After replacing the sensitivities in the code with the figures appropriate for my IMU, there is still some fluctuations in the X-Y axis output when the accelerometer is flipped over 180 degrees. This may be from a value set for the gyroscope to switch signs when the IMU is inverted.

Complete Team Page
Fill out the Team Form (should have already copied the form, created the team page, linked to it and started filling it out).