Purdue Space Program - Active Controls
I joined the Active Controls team during their second year and worked with my peers to bring ASTRA, our team’s first lander vehicle, to life. The primary goal of ASTRA is to serve as a test platform to develop various control algorithms, as well as electrical and structural components.
I served the team as Structures Lead for a year, where I worked to convert the vision into design and designs into parts. Subsequently, I became the Avionics Lead where I worked with interfacing with the flight computer, and tested the vehicle’s hardware.
I am currently the Systems Lead on this team with a focus on Vehicle Integration and Testing.
To learn more about what we do, you can visit our website: http://purdueseds.space/active-controls/
My Contributions
Structures Leadership:
I joined the structures team during its early stages and managed a team of roughly 10 members. My primary work initially was to set up a workflow and guidelines for the team to follow through in their design process. I incorporated workflow management tools like Jira and Confluence to document and handle the design process.
On the technical end, we set up a lot of the infrastructure required for ASTRA, such as test stands, and overall frame setup. My responsibilities also extended to weekly meetings with leadership to set aside goals for the team's development. A major challenge during my tenure was to handle the adoption of a second project while concurrently developing ASTRA, this second project has now turned out to be the liquid-fueled bi-propellant lander we call TOAD, and its engine - TADPOLE.
Avionics Leadership:
As Avionics lead I primarlity oversaw the testing of ASTRA. I oversaw a team of 3 members. We developed testing scripts to control the hardware on board, integrated sensors into the vehicle, and conducted System Identification for developing our control system. We also supported the Controls team with developing flight software code, and developing the test enviroment and set up for tuning our controllers.
Our team is primarily comprised of students pursuing Aeronautical and Astronautical Engineering, as such, we all needed to learn more about electrical systems. To promote individual skills among team members, I conducted tutorial sessions where I taught the basics of Arduino and C++ to the members using TinkerCAD.
My role here saw me gain familiratiy with CAN, I2C, and SPI protocols, and I gained experience working with electronic hardware such as servos, linear acutators, throttle valves, sensors, and many other components.
Sensor Calibration:
Our test stands used 4 HX711 force transducer’s, due to all of them having the same device ID, as a quick fix, we resorted to operational amplification of the signal to get the force reading. However we had to identify the weights associated with each sensor’s digital output.
In order to solve this problem, I was able to apply topics used in my Kaman Filtering class to calibrate the sensors. By defining the digital readings for various weights as the basis of a Hilbert Space, I was then able to use the projection theorem to project the vector of the “true weights” onto the Hilbert space and find a set of calibration weights for each digital signal that minimized the error between actual weight and calculated weight.
Gimbal Design:
As a member of the structures team, I developed ASTRA’s thrust vectoring system (A gimbal with 2 degrees of freedom). I worked with my peers to establish requirements for the system. The assembly was 3D printed, with a couple of COTS parts. The end product was a 3-piece assembly capable of providing thrust vectoring of up to 13 degrees in either axis. This Gimbal is currently being used for tuning our control system.