Space Dynamic Laboratory Stiffness Tester Upgrade
Team: Spencer Stuart, Josh Sorenson, Cody White, and Shane Boyce
Sponsor: Space Dynamics Lab
Objective: Automate a thermal strap stiffness test apparatus at Space Dynamic Laboratory to improve accuracy, consistency, and efficiency in multi-axis positioning and force measurement of Thermal Straps.
The Problem to Fix
Thermal straps at SDL must be tested for stiffness by displacing one end and measuring the resulting force. The previous test setup required manual displacement, which introduced variability, increased test time, and risked damaging the strap due to over-displacement.
The Solution
We designed and built a semi-automated test system to improve repeatability, accuracy, and safety.
Automated x-axis with LabVIEW control and a precision motor
Manual override crank for flexible operation
Linear rail y-axis for precise, easy alignment
Upgraded load cell for improved force resolution
Hard stops to prevent over-displacement and protect the strap
Retained z-axis system due to its existing reliability
Upgraded Stiffness Tester Setup
Y Axis Linear Displacement Rail
The y-axis features a linear rail system that replaces the previous screw-based adjustment, allowing for smoother, more precise manual alignment during setup.
Z Axis Precision Scissor Lift
The scissor lift, mounted behind the vertical attachment plate, provides adjustable height control, allowing for fine z-axis positioning during strap setup and alignment
Simulator Strap
A simulator strap was used in place of a real thermal strap to safely test the system’s movement, accuracy, and reliability without risking damage to actual hardware
Raised Mounting Plate and Digital Read Out
The digital force readout displays real-time strap force measurements from the load cell, mounted on a raised plate to improve visibility and accessibility during testing.
Improved GUI LabView Interface
The updated LabVIEW GUI provides intuitive control of the x-axis motor and real-time force monitoring, streamlining the testing process and improving user interaction.
Load Cell
The upgraded high-accuracy load cell enhances force measurement precision, ensuring more reliable stiffness data during thermal strap testing.
Failsafe Hard Stops
The fail-safe hard stops are integrated into the x-axis rail to prevent over-displacement, protecting the thermal straps from potential damage due to user error or motor malfunction
Computer Controlled Linear Motor
The motorized x-axis linear rail enables precise, controlled displacement of the thermal strap through LabVIEW automation, reducing human error and improving test repeatability.
Completed Stiffness Tester
Customer Requirements
| Requirement/Constraint | Target | Threshold |
|---|---|---|
| X-Axis Motor That Displaces Within .001" | Increase speed and consistency of data collection | .001" adjustment increments |
| Y-Axis Linear Rail Adjustable to .001" | Accurately position strap while reducing set up time | .001" adjustment increments |
| GUI Accurate to .001" | N/A | Records data within .001" if required displacement |
| Updated Load Cell | Load cell that collects data within 20–80% of instrument range | .005lb data collection intervals |
| Test Limit Hard Stops | N/A | Limits movement within .001" increments |
Results
The updated test system enhances efficiency, accuracy, and strap protection, offering a more reliable and user-friendly solution. This project provided valuable experience in mechanical design, motion control integration, and system validation.
Next Steps
Future steps may include automating the y- and z-axes and implementing a programmable 3D coordinate system for more efficient setup and enhanced automation.