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uf-mil-archive / PropaGator

ROS packages specific to the PropaGator robot
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Azi drive produces a torque with opposite sign of desired #27

Open fnivek opened 9 years ago

fnivek commented 9 years ago

If a positive (clockwise) torque is given azi drive produces a negative torque (counterclockwise). I have temporarily fixed it with this commit but Jake you may want to look into your math and fix it appropriately.

jpanikulam commented 9 years ago

Hmm, seems to work right on my machine, but I'm not running the latest Propagator.

Are you using the x-forward y-right convention? Positive torque would turn the boat right, in that case.

forrestv commented 9 years ago

So... hopefully everyone is using x-forward y-left (z-up), because, you know, that's what everything else uses and is the ROS standard local coordinate system. Positive torque is CCW rotation/turning left, which contradicts what Kevin said. (EDIT: Oops, nevermind that last sentence, he was describing the problem.)

fnivek commented 9 years ago

Sorry I was quite tired when I posted this issue last night I meant to say positive is CCW and negative is CW. As for x forward, y left, and z up, everything except Azi drive follows that convention. Jake positive torque should turn the boat CCW or left, and negative torque should turn the boat CW or right.

fnivek commented 9 years ago

It looks like there is also a sign error in the Y direction, if azi drive really is x forward Y right z down. In your convention, when given a positive Fy it should move right. On my system a wrench with negative Fy moves right and a wrench with positive Fy moves left contrary to the x forward Y right z down convention. (Fortunately for today's test day this is actually beneficial)

jpanikulam commented 9 years ago

ROS standards vs. nautical standards, does Poseidon supercede OSRF?

I guess not. Will fix it.

On Jun 10, 2015, at 4:54 AM, Forrest Voight notifications@github.com wrote:

So... hopefully everyone is using x-forward y-left (z-up), because, you know, that's what everything else uses and is the ROS standard local coordinate system. Positive torque is CCW rotation/turning left, which contradicts what Kevin said.

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