Hi,
I am currently experimenting with and validating different 3D printing materials for the 3D Printed Motor Mounts. I was wondering if you could share what tests you conducted to validate your design using the Onyx filament.
I am specifically focusing on the hip ad/abduction block (both the hip and leg sides), as well as the motor-to-leg shell interface. What mechanical tests would you recommend for these components? Additionally, based on your testing and experience with OpenExo, what are the primary load cases acting on these parts?
Thanks,
Lauren
Hi Lauren,
The tests conducted consisted of a handful of 20min walk tests at a 6Nm torque setpoint for the Franks Collins controller, which is considered a fairly high setpoint. The Ad/Abduction Block (Leg Side) is most vulnerable to shear- which was the most common failure mode when inadequate carbon fiber infill was used. The Ad/Abduction Block (Leg Side) did not fail during any tests, though it does display some flex at higher setpoints, making the torque transmission slightly less effective and possibly introducing a long-term failure mode that was not encountered during testing.
One thing to note is that 9Nm (the max motor output) was considered to be excessive for the Franks Collins controller, which was the only actively used hip controller at the time. As such, testing at 9Nm was limited. Reviewing the documentation, this fact isn't clear so I'll update it now to be more accurate.
Hope that's helpful,
Noah
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