RATHCA
The below explanation(approx 3-5 minutes reading time) details my project for which I was responsible for every aspect of the design. With this I intend to show that I have experience finding holistic and complete solutions for problems.
The Robotically Automated Thermometer and Hygrometer Calibration Apparatus(RATHCA) enables calibration technicians to interface with test instruments that are sealed in a test chamber. I am the sole engineer and author on the patent application(ongoing).
Thermometers such as those below(bottom left) are calibrated via a test chamber(bottom right) that can be set to varying temperatures and humidities.
Until my invention came along, the state of the art method for interfacing with these instruments when under test was to insert a broomstick(pictured below) and interact with the instrument as needed. As ridiculous as that process is, it is currently standard practice across the USAF calibration laboratories.
Since the moment I was trained on that method, I knew it needed to be improved.
I decided to create a Cartesian robot to hold the instrument under test and to interact with it via a Z axis linear actuator. The robot is controlled via a joystick-based control system.
Care was required in selecting the components, especially the motors and structural materials since operating conditions were expected to be as high as 80°C.
After the motors and other components were selected, I drafted a prototype. The first draft is pictured below.
In my preparation to request funding, I performed a simple cost analysis by parsing calibration data per base and normalizing by several variables to find the actual workload of items per base, and identified that the five top producing bases shouldered 60% of the total Air Force workload. This was important to know when requesting funding because it meant that I could have a huge impact on my organization with only five constructions, as opposed to the dozens it would require to supply every lab in the Air Force. I would show the details of how I parsed the data, but that information is too sensitive for a personal website such as this one.
In March '22 I pitched my invention to Colonel Simmons, the then Base Commander of Travis AFB. He granted me all the funding I requested, and awarded me a winner of the competition.
Now armed with funding to continue development, I decided that it would be simpler to construct a frame from 80/20 extrusions and make custom 3D printed adapters for my various hardware, yielding the draft below.
The first functional prototype(pictured left) came online in September '22, after some budget delays.
Testing showed the need for an aiming device as well as the need for lighting inside the chamber. I revised the designs to accommodate these needs.
I installed a laser pointer for aiming the device and a clear LED for illuminating the work area. Those modifications are highlighted below in the detailed views, where the blue arrow points out the laser pointer and the red arrow points out the clear LED.
Below are some closeups of the custom made 3D printed attachment fixtures.
As for the circuitry, I made a reference schematic for all of my wiring and setup a prototype. In retrospect, this was a very crude schematic, but it served its purpose at the time. After checking functionality on the prototype, I designed and constructed a more permanent fixture to include a fan, on/off LED, SPST on/off toggle switch, and custom JST port connectors for the motors.
It was at this point that my period of service in the Air Force started to conclude, so I passed off my project to an engineer at the Air Force Research Laboratory. While I would prefer to see my project through to maturity, the nature of government funded projects means that I just didn't have enough time.
I'm quite happy with where I got this project to, and the lessons(i.e. mistakes) I learned along the way will be immensely valuable moving forward. I am eager to apply those lessons in my future robotics projects.
To learn about what I'm working on now, feel free to reach out to me via the email listed on my home page.
