Author Topic: Rotate MastCam 90 degrees  (Read 744 times)

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Offline ron2020Topic starter

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Rotate MastCam 90 degrees
« on: August 01, 2012, 10:05:32 AM »
Hi everyone,

I think many of us have seem the simulation video of the Mars Curiosity rover as it rotates its mastCam by 90 degrees from a horozontal level to vertical, here's the video (starts at 2:16):
Next Mars Rover in Action-Animation


I'm trying to figure out the best way to do exactly this with my camera and mast. 
What is the best way to rotate my mastcam from the horozontal to the vertical?  A wormgear? A linear actuator?  After it rotates to the vertical, I would prefer not to use any power to keep it up (or to keep it in the horotonal resting position).

Can anyone offer any ideas on how to best emulate this motion?

Thanks very much, in advance.

ron

Offline rodstar

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Re: Rotate MastCam 90 degrees
« Reply #1 on: August 01, 2012, 10:41:36 AM »
If I understood your question, I would suggest to use belt transmission (gears use to perform annoying play). To keep it steady without energy ("while off") you may use a belt or chain brake, another choice is to use magnetic brakes like big servomotors do: while energized they will release for rotation, and while not energized: they will be braking as hell.

It depends on how "heavy duty" you want to design your mechanism, if not so, I think a cheap & fast solution is a worm based gearbox as you say, but they must be replaced quite often as they get a lot of attrition... you must regularly bath it in a lot of grease because they are based on graze contact. In Mars, grease would melt, lol.

Offline rodstar

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Re: Rotate MastCam 90 degrees
« Reply #2 on: August 01, 2012, 10:46:56 AM »
here's a mini brake in action
Electro Magnetic brake
« Last Edit: August 01, 2012, 10:50:28 AM by rodstar »

Offline ron2020Topic starter

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Re: Rotate MastCam 90 degrees
« Reply #3 on: August 01, 2012, 11:10:00 AM »
this is very interesting - an electromagnetic brake.  I must look into this.

thanks very much!
ron

Offline Soeren

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Re: Rotate MastCam 90 degrees
« Reply #4 on: August 03, 2012, 08:46:14 AM »
Hi,

[...] After it rotates to the vertical, I would prefer not to use any power to keep it up (or to keep it in the horotonal resting position).
A spring loaded and solenoid-released latch (think door latch) locking each position would only take a little power to disengage until the "knee" has rotated less than half the width of the latch (1° should do if made well and would be positively locked in each position.
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

 


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