USLI Team National Instruments Finalist
The awards of the USLI senior design team continue to come. This team was just named a top 3 finalist by National Instrument in their nationwide student competition. The project included a dynamic thrust modulation system, ground hazard identification system, atmospheric sensor package, as well as a dynamic analysis of structural elements.
The largest portion of the project involved dynamically controlling the thrust from a solid fuel rocket motor during motor burn to achieve a desired altitude, as well as conducting a dynamic analysis of propulsion during boost and protuberances during flight. To date, NASA has not successfully implemented a thrust modulation system on a solid fuel rocket. Modulating thrust in a liquid fuel motor is achieved by altering the air-fuel mixture in the motor, which is not possible in a solid fuel motor. Experimentation was required to determine a method to modulate thrust during motor burn of a solid fuel motor. A variable nozzle extension, activated by a high torque servo motor and controlled via a closed-loop system with feedback from an onboard accelerometer served to modulate thrust during the motor burn, which only lasted 3.69 seconds. This modulation decreased the efficiency of the thrust and allowed the team to decrease acceleration, and limit the final altitude to near the desired 3100 feet. This system operated on a NI myRIO DAQ/microcontroller, which also record the data received from the strain gauges mounted at strategic locations on the vehicle and in the modulation system. Based on the launch vehicle size, mass and engine thrust the vehicle should have attained an altitude of 4,900 feet, 1,800 feet higher than the team mandated 3,100 feet.
The second payload module incorporated a ground scanning hazard detection camera which ran independently of the thrust modulation system, and employed a high-definition 5MP digital camera to scan the landing area to locate any landing hazards. The camera deployed and activated at 800 feet above the landing area, and scanned the area processing the data to determine if any pre-specified hazards were visible in the camera’s field of vision. All data was processed onboard via a separate myRIO unit, along with data from various atmospheric sensors to determine ambient conditions during descent.
The launch vehicle flight plan with key tasks identified is shown below.