Case Study
Needle Insertion Mechanism
Challenge
- Client trapped in a Design-Build-Test and iterate loop.
- “Test-to-success” mindset.
- Required a more effective and predictable approach to develop a robust actuator for needle insertion.
- Required drop-in solution, spatially constrained, limited power available, complex load profile
Approach
- Develop an empirically based analytical load profile with ±4-sigma limits
- Research available motors, identify viable gear reduction ratios
- Define key functional and testable requirements – “system curve” – and success metrics
- τ, No Load Speed, stall force
- Build dynamic model of system
- M-C simulation to predict robust performance
- Developed tester and protocols for empirical verification.
Results
- Identified most robust configurations for implementation
- Built and tested 10 units
- Expected ~2x robustness increase
Measured 2 to 3x performance increase using the same metrics – empirical and analytical model agreement
Key Takeaways
- Analytical model informed by empirical results provided practical and cost-effective down-select process
- Several viable design alternatives
- Models predicted Performance – robust by design!
