Animatronics

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Gregg
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Animatronics

Post by Gregg » Sun Jul 07, 2002 8:35 am

Looking for information on animatronic figures. Mostly "people" type..........info on actuators for lip and eye movement, and control system for the control of it. Any ideas on construstion and where to buy stuff CHEAP would be great. Many thanks.

hlreed
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Re: Animatronics

Post by hlreed » Sun Jul 07, 2002 10:11 am

Greg,
All active machines can be divided into sensors and motors. Disney type machines are mostly motors, driven by a remote person or computer.
Motors are actuators. There are two types of motor action. From number to velocity, or from number to position.
This whole area is motor interfacing with nature. This is where all the engineering is needed. There are no standards here yet, which means no mass production, which means high cost. Animatronics is a nice name, but it does not mean anything.
When you design a smile or frown, you must model the human action to the machine action. This is easy to imagine and hard to do in hardware. There is no cheap, easy way to do all this.
Harold L. Reed
Microbes got brains

Faulkner
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Re: Animatronics

Post by Faulkner » Tue Jul 09, 2002 9:36 pm

Some people have had success using muscle wire to make facial expressions. It's thin and easy to use, but reaction time is very slow. Maybe some kind of pneumatics? Try a search on google for Kismet at MIT, or the Hara-Kobayashi Lab at the science university in tokyo. They're only heads, but pretty neat.

bobsRAC
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Re: Animatronics

Post by bobsRAC » Sun Jul 14, 2002 1:16 am

Nitinol is worth looking into. It's a shape-memory alloy. I'd look here first for info.<p>Pneumatic muscle actuators (PMA) are promising for natural muscle-like properties. They have comparable force control, flexibility, and position control, as well as greatly increased power to weight, force to volume, and force to diameter ratios.

Isenbergdoug
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Re: Animatronics

Post by Isenbergdoug » Tue Jul 16, 2002 7:25 pm

This is just an idea, but, perhaps nitinol could be molded into a latex "mask". The latex is essentially "cast" so the nitinol could be placed where movement is needed. There may be some need to anchor the wires in the latex, but it may be possible to create something very life like doing this. With the mechanics worked out, I believe the electronics involved would possibly be easier than using motor control.

bobsRAC
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Re: Animatronics

Post by bobsRAC » Wed Jul 17, 2002 6:09 pm

Nitinol might not work in such an application b/c it only provides 3% +- contraction. This can be amplified by wrapping the wire about a strong non-conductive spool, but 30% (the contraction provided by human muscles) seems highish.<p>If you can figure out a way to do it, I'd be VERY interested in hearing about it.

hlreed
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Re: Animatronics

Post by hlreed » Thu Jul 18, 2002 9:35 am

Eye movement is easily done with a couple of light sensors on the arm of a servo. To make this work you have to be digital. To feed the servo from a number, you need a servo node. To feed the servo node you need to subtract the input from the two sensors. The eye will follow simularity. That is, the system seeks zero. The equation is:
Servo = lightLeft - LightRight or reverse if need be.
I have all this stuff, but it is not in production yet, so the cost is high.
Of course you need two of these.
That is: two light sensors, two ADC, one CNode and one SMNode for each, and a battery node to run them.
Mouth expression can be done by pulling up the corners. Smile = good - bad ; Here Smile is the motor that makes the lips curl. good and bad can be numbers from anywhere. One CNode is required.
All this is cosmetic. You need to have some computation of good and bad to have a real person.
Harold L. Reed
Microbes got brains

Gregg
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Re: Animatronics

Post by Gregg » Thu Jul 18, 2002 7:26 pm

Wow thanks guys....i think the last post by HAROLD is more of what i am looking for, the disney type figures. Facial expressions, servo positions, control systems ( not microprossor based more joystick controlled).<p>[ July 18, 2002: Message edited by: Greg ]</p>

toejam
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Re: Animatronics

Post by toejam » Tue Jul 23, 2002 5:10 am

I think the easiest way to do this would be to buy a model radio control transmitter and reciever.They come equiped with a servo for each channel. You than have pretty strong servos that respond to the position of the control lever on the transmitter.

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