Society of Robots - Robot Forum
Mechanics and Construction => Mechanics and Construction => Topic started by: VegaObscura on October 20, 2010, 10:50:07 PM
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In my opinion, one of the most important parts of a robot is the ability to reach out and do something. Sure, that could be done with a robotic arm, but I think that would seriously over complicate an otherwise fairly simple task. I want to learn how to cheaply make a pole that extends straight out. All the linear actuators I see online cost around $100 and are capable of much more powerful feats than most people need. I want to find a way to create an extending pole (I wouldn't call it an arm) with a stroke of about 1 foot and material cost of about $15. Does anyone have any idea how to get started? Am I being too optimistic with my goals?
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I'd guess a gear rack + gearmotor would do the trick, with feedback from an encoder?
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Gear rack + motor was what I was going to suggest too. Here's a servo-mount gear (http://www.servocity.com/html/gears___sprockets.html) and a gear rack from servo city.
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A lead-screw is another good way to do a linear actuator. This does have excellent holding without applying power to the motor and can be slow/hi-torque or fast/low-torque depending on the lead pitch.
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Yes, plus one for screwing ;)
For simple apps. a length of cheap threaded rod can be used with regular nuts, however, the thread is not shaped for load bearing, so for powering up, the screw from a scissor car jack is a much better choice - Just look around and you'll find usable screws in different sizes.
An alternative could be a folded arm swinging open by a servo or similar.