WARNING: New servos may be dangerous!

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RDoherty's picture
Title: NooBot+
Joined: 05/18/2011
BotPoints: 9
User offline. Last seen 6 years 29 weeks ago.

While developing a horizontal grabber to pick up blocks we had the mechanism jam sliding horizontally. A gear on a new, high-torque servo was on an axle shaft and drove two racks in opposite directions. Here's the dangerous part: The servo had enough torque in the jammed mechanism state to twist the axle shaft 90 degrees over a distance of maybe 12 mm. The gear slipped off the end of the staff and flew 5 meters at high velocity across the room and hit the wall with a substantial thwack.

I am recovering from a detached retina and two eye surgeries caused by being hit in the eye over a year ago, so I am sensitive to the concept of eye safety. PLEASE CHECK ANY MECHANISM YOU BUILD USING THE NEW SERVOS! Make sure parts can't fly off if the servo moves and the parts don't. In advanced engineering circles this is called Failure Energy Management.

If a robot is misbehaving, it's doing EXACTLY what you told it to do.

Jeremy Rand
Jeremy Rand's picture
Title: Botball Youth Advisory Council
Joined: 04/03/2009
BotPoints: 1168
User offline. Last seen 2 years 29 weeks ago.

Scary stuff, thanks for sharing.

-Jeremy Rand
Senior Programmer, Team SNARC (2012-2013), Norman Advanced (2010-2011), Norman HS (2008-2009), Norman North (2005-2007), Whittier MS (2003-2004)
2012-2013 VP of Tech, 2011 President, Botball YAC (2009-2013)
Mentor, Alcott and Whittier MS