Engine and body selection for Random Positioning Machine(RPM)

Support Finding Parts
1

I am developing a Random Positioning Machine (RPM) to simulate and test microgravity environments. I previously followed a 3D-printed design that utilized FS90R continuous rotation servos, but my requirements are much more demanding. I need to run this experiment continuously for 72 hours (3 days).

I have already tried using MG90S and MG996R servos, but they were neither effective nor durable enough for long-term continuous operation. They suffer from overheating and jitter issues over time. I am now considering switching to Stepper Motors (NEMA 17) for better torque and reliability, but I have a few concerns:

  1. Weight & Structural Integrity: Stepper motors are significantly heavier than servos. I am unsure if a 3D-printed frame can handle the weight and vibration of two NEMA 17 motors over 72 hours. Should I transition to a metal/aluminum frame, or would a belt-driven system (keeping the motors stationary or off-axis) be a better approach to reduce the load on the moving parts?

  2. Mechanical Design: How should I approach the design to ensure the inner frame can rotate freely without putting excessive stress on the motor shafts?

  3. Measuring Microgravity: Can I accurately measure or verify the simulated microgravity using an accelerometer (like the MPU6050)? Is a standard IMU sufficient for this purpose, or are there more specialized sensors I should consider?

  4. Simulation: Is there a way to simulate the RPM’s motion profile or the resulting gravity vectors before building the physical prototype?

  5. For better understanding : https://www.youtube.com/watch?v=Wz8sjB6MxHA&lc=UgwBTe0DjozxPRrxCD14AaABAg.AVGwxJA2XgjAVHA9UJ054o

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Hey there, @Pnar316931, and welcome to the forum. Glad to have you here.

I think moving away from hobby servos is the right call. From the technical data on the parts we stock, the stronger NEMA 17 option here is this Pololu stepper, and it sits in the usual NEMA 17 class with a 42 mm face, 5 mm shaft, about 285 g weight, and 3.7 kg·cm holding torque. That’s enough to be worth considering, but I’d still avoid using the motor shaft as the main structural support for the rotating frame.

On the control side, a TB6600 stepper driver is a reasonable match for NEMA 17 motors in this range. The technical data shows it supports 9–42 V supply, adjustable current, microstepping, and it’s commonly used with NEMA 17s, so it’s a sensible starting point for continuous operation.