Flight Test Data System for Strain Measurement

• Main Author: Wilson, Zachary David
• Format: Others
• Published: DigitalCommons@CalPoly 2019
• Subjects: Strain; Measure; BLDS; Modular; Static; Dynamic; Arduino; C; C++; Other Mechanical Engineering
• Online Access: https://digitalcommons.calpoly.edu/theses/2121; https://digitalcommons.calpoly.edu/cgi/viewcontent.cgi?article=3571&context=theses

This thesis describes the design and evaluation of two devices to be included in the next generation of the family of devices called the Boundary Layer Data System (BLDS). The first device, called the Quasi-Static Strain Data Acquisition System, is a continuation of the BLDS-M series of devices to be known as the Flight Test Data System (FTDS) that uses a modular approach to acquire non-flow, quasi-static mechanical strain measurements. Various breakout boards and development boards were used to synthesize the device, which were housed by a custom PCB board. The system is controlled by the SimbleeTM System on a Chip (SOC), and strain measurements are acquired using the HX711 analog-to-digital converter (ADC), and acceleration measurements are acquired with the ADXL345 accelerometer. The Arduino IDE was used to program and troubleshoot the device. The second device, called the Dynamic Strain Data Acquisition System, is a laboratory proof-of-concept device that evaluates various methods of acquiring dynamic strain measurements that may be used in future FTDS designs. A custom PCB board was designed that houses the microcontroller and the various passive components and ICs used to acquire and store strain measurements. The system is controlled by the Atxmega128A4U microcontroller, and measurements are acquired using the AD7708 external ADC and the on-board ADC of the microcontroller. Atmel StudioTM was used to program the microcontroller in C/C++ and to troubleshoot the device. Both devices were tested extensively under room temperature and low temperature conditions to prove the reliability and survivability of each device. The quasi-static data acquisition system was validated to acquire and store measurements to a microSD card at 10 Hz, with a peak operating current under 60 mA. The dynamic data acquisition system was proven to acquire a thousand measurements at 1 kHz and store the data to a microSD card, with a peak operating current under 60 mA.