Stepper? Servo? What is this?

[KAS]

I'll have to get that at work tomorrow. That stuff above was in my notes from my last attempt.

[Generic Default]

Wait, is that potentiometer-motor combo the same thing that cost 36 thousand dollars? Are there 2 of those per axis? 2 axes? Lawd have mercy, do they have four $36,000 parts just to point a camera?

I thought the torque motor and feedback were separate things much bigger than that. So it's just a potentiometer with some motor coils in it...No laser gyro.

I guess that explains the wiring a lot better. This whole setup is as simple as an arduino controlling two hobby servos.

[626Pilot]

At first, I thought the torque motor would be a constant-velocity DC motor, and the "pickoff" was something like a torque converter, where it would transmit torque to the output according to how much current you put through it.

Now, after all the photos and discussion, it reminds me more of a floppy disk motor with its position sensors. Because it has such a limited range, simple position sensors would not be enough, and it would need a potentiometer setup instead. That makes a lot of sense. One of the pots is set up like a sine wave, the other a saw wave. They probably read both of them and then take the average reported position, good in case one of them should fail or become unreliable.

[jdurand]

Back in the olde days we used to drive mag tape with torque motors. You hook them up to an analog board and tell it how much tension to hold on the tape and it did just that, the motors/electronics put out a constant torque from dead stop to turning fairly fast in either direction.

[KAS]

Received some info back regarding the technical usage of torque motors and pickoff. Basically the torque motors are given a specific voltage to lock the camera in a center orientation with very limited range of motion , not meant to move like a camera gimbal we would think of. The pickoffs sense variation from camera center and align the weapon guidance section to match center of camera. The WSO ( Weapon System Officer) guides the weapon onto target using the camera. The camera doesn't actually move, it's the digital imaging reticle overlay that they control with the guidance section playing catch-up. The pickoffs just provides measurements to the guidance and targeting section for alignment verification that the camera is in correct location and not pointing off skew causing the weapon to miss target.


Honestly it looks like you're controlling the camera when in fact you're just aligning the bomb to your sights.



[youtube]http://www.youtube.com/watch?v=ZJOWHdMVMAY[/youtube]

[Generic Default]

Ohhh so its a TV guided bomb.

I'm not exactly sure why they don't just mount the camera rigidly to the frame of the bomb behind the dome window. If the entire purpose of the gimbal is just to point the camera forward, why???? Even laser gyros would be cheaper at the cost of this unit, and they would work just as well.

I thought the whole point of having a precision gimbal was to track targets, like how the gimbal works on a MANPAD or other AA missile system.

Still really cool though, thanks for taking time to show this to everyone KAS!

[barry99705]

Ohhh so its a TV guided bomb.

I'm not exactly sure why they don't just mount the camera rigidly to the frame of the bomb behind the dome window. If the entire purpose of the gimbal is just to point the camera forward, why???? Even laser gyros would be cheaper at the cost of this unit, and they would work just as well.

I thought the whole point of having a precision gimbal was to track targets, like how the gimbal works on a MANPAD or other AA missile system.

Still really cool though, thanks for taking time to show this to everyone KAS!

It's a 2000 pound bomb, with a rocket motor strapped to the bottom!

Here's how they work, pretty neat and stupid accurate.

[youtube]http://www.youtube.com/watch?v=5-8LU9mvXRo[/youtube]