Add Why Run To Position Mode Is Not A Good Idea #38
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Thanks for the patch!
This overall looks great and I really appreciate adding this to cookbook; this is something that would have directly saved my team at state this year.
I have individual comments with some nitpickier changes and expansions I'd love to see as well.
| When using a PID(F) controller to move a motor to a certain position, it is often tempting | ||
| to use the `RUN_TO_POSITION` mode, especially since it appears in many examples. | ||
| This motor run mode is built into the FTC SDK and is designed to move a motor to a certain encoder position autonomously. | ||
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explain why RTP is so weird here; it's because it runs on the expansion hub/control hub's internal expansion hub
then explain how the other errors connect to that (it's the cause of them)
| * This is known as sample rate: Here's a [demo](https://www.youtube.com/watch?v=fusr9eTceEo&t=133s) of its effect | ||
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| ### Why going Custom PID(F) is better: | ||
| With a custom PID(F) controller, you can update the motor's position every loop. Since most FTC loops run at higher than 20hz, |
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change to every loop of your OpMode, also give an example of what rate FTC loops run at (such as 100-200hz) and compare it to RTP
| Imagine a scenario where you are trying to move a motor to a certain position. | ||
| If the motor is moving too fast, it will overshoot the target position and then have to correct itself. | ||
| However, if the motor is only updating its position 20 times per second, it will not be able to correct itself quickly enough, | ||
| leading to overshoots and even oscillations. |
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mention that this can especially be a problem with arms but RTP can sometimes work well on slides
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| First, this syntax is required to be followed exactly. This means that if you want to switch between manual and automatic control, | ||
| you will have to change the motor mode every time you switch. Programming any FSM or even any complex auto becomes quite difficult. |
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change "Programming any FSM" to "This can add significant complexity to coding autonomous" or something like it
| First, this syntax is required to be followed exactly. This means that if you want to switch between manual and automatic control, | ||
| you will have to change the motor mode every time you switch. Programming any FSM or even any complex auto becomes quite difficult. | ||
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| While this seems like a minor inconvenience, if done in the wrong order, it **crashes the entire bot without outputting any useful error messages**. |
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change "if done in the wrong order, it" to "messing it up"
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| - https://www.ctrlaltftc.com/feedforward-control | ||
| - https://www.youtube.com/watch?v=E6H6Nqe6qJo | ||
| # Sooo, how do I solve it? |
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or remove entirely "How do I solve this?" / "What are some better approaches?"
| PID(F) controllers seem scary, but they really aren't. All they do is try to get a motor to a certain position and hold it there. | ||
| Here's a [guide](https://www.ctrlaltftc.com/pidf_controllers/integrating_a_custom_PIDF_controller) on not only how to implement one but the logic. | ||
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| And of course, if you don't wanna do that or code your own, there are libraries like [FTCLib](https://ftclib.org/) and [Homeostasis](https://www.ctrlaltftc.com/homeostasis-by-thermal-equilibrium/what-is-homeostasis) that have PID(F) controllers that are just plug-n-play (with tuning of course). |
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wanna do that or code your own -> want to code your own
| - https://www.youtube.com/watch?v=E6H6Nqe6qJo | ||
| # Sooo, how do I solve it? | ||
| PID(F) controllers seem scary, but they really aren't. All they do is try to get a motor to a certain position and hold it there. | ||
| Here's a [guide](https://www.ctrlaltftc.com/pidf_controllers/integrating_a_custom_PIDF_controller) on not only how to implement one but the logic. |
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change to something like Here's a guide explaining both the implementation and the math behind them.
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| And of course, if you don't wanna do that or code your own, there are libraries like [FTCLib](https://ftclib.org/) and [Homeostasis](https://www.ctrlaltftc.com/homeostasis-by-thermal-equilibrium/what-is-homeostasis) that have PID(F) controllers that are just plug-n-play (with tuning of course). | ||
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| If you're using Roadrunner, you can use this [recipe](https://cookbook.dairy.foundation/roadrunner_056/how_to_integrate_a_PIDF_controller_with_roadrunner/how_to_integrate_a_PIDF_controller_with_roadrunner.html#pidf-controller-and-gains) |
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something like "this recipe shows how to integrate them into your Road Runner autonomous"
| PID(F) controllers seem scary, but they really aren't. All they do is try to get a motor to a certain position and hold it there. | ||
| Here's a [guide](https://www.ctrlaltftc.com/pidf_controllers/integrating_a_custom_PIDF_controller) on not only how to implement one but the logic. | ||
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| And of course, if you don't wanna do that or code your own, there are libraries like [FTCLib](https://ftclib.org/) and [Homeostasis](https://www.ctrlaltftc.com/homeostasis-by-thermal-equilibrium/what-is-homeostasis) that have PID(F) controllers that are just plug-n-play (with tuning of course). |
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mention dairy, potentially don't mention homeostasis? is it updated?
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| # Why Run To Position Is Not A Good Idea | |||
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This title could be better phrased.
"Not A Good Idea" is fairly weakly worded, I think a simple "Why Not Use RTP" or "Do Not Use RTP" is more direct and better.
| - https://www.youtube.com/watch?v=E6H6Nqe6qJo | ||
| # Sooo, how do I solve it? | ||
| PID(F) controllers seem scary, but they really aren't. All they do is try to get a motor to a certain position and hold it there. | ||
| Here's a [guide](https://www.ctrlaltftc.com/pidf_controllers/integrating_a_custom_PIDF_controller) on not only how to implement one but the logic. |
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Add the gm0 page as well.
| PID(F) controllers seem scary, but they really aren't. All they do is try to get a motor to a certain position and hold it there. | ||
| Here's a [guide](https://www.ctrlaltftc.com/pidf_controllers/integrating_a_custom_PIDF_controller) on not only how to implement one but the logic. | ||
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| And of course, if you don't wanna do that or code your own, there are libraries like [FTCLib](https://ftclib.org/) and [Homeostasis](https://www.ctrlaltftc.com/homeostasis-by-thermal-equilibrium/what-is-homeostasis) that have PID(F) controllers that are just plug-n-play (with tuning of course). |
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Add a line recommending that students try programming one at least once.
docs: explain limitations of RUN_TO_POSITION and benefits of custom PID(F) controllers
This recipe provides a comprehensive understanding for teams transitioning from
RUN_TO_POSITIONto custom solutions.