6-Foot Falling-Up Robot with Steppers

[E-V-L]

Had a heck of a time dealing with stepper induced vibration. It confuses the tilt sensors making it difficult to balance the 6-foot tall robot. Aside from microstepping and using sinusoidal current control, not sure what more can be done aside from filtering the accel & gyro measurements. I think it worked out okay, but if there's more that can be done, I can use the tip.



I used the ST-M5045 stepper drivers found at Sainsmart. Stepper are KL23H276-28-4B dual-shaft 2.8A motors.

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[James Newton]

1. The linistepper provides a much smoother signal. Not perfect, but closer to a sine wave.
2. A hocky puck on the shaft can absorb vibration.
3. A quick running average on the sensors can extract the trend from noise.

[E-V-L]

Okay, I got the XBEE communication working with the Teensy 3.6 mcu, and able to send motion commands to the Falling-Up Robot. Able to yaw and translate the 6-foot robot while maintaining tilt stability. It's no longer tethered to the USB port and the power supply unit. See latest video below. Recommend headphones.

[James Newton]

So? How did you resolve the vibration problem?

[E-V-L]

So? How did you resolve the vibration problem?

I installed rubber vibration isolators from McMaster-carr between the stepper motors and mounting brackets, and I use ST-5045 stepper drivers with sinusoidal current control and microstepping. These attenuate the vibration to tolerable levels. Originally the robot had $20 drivers without sinusoidal current control, and it shook the whole robot frame in a noisy manner. Still, even with the fixes, some panels still vibrated at certain RPMs, so I put aluminum tape over those as a damper.