What Does PID Do In Fardriver Parameters?

Added: 2026-05-25

[00:00:02]All right, chill day on the old e-bikes.

[00:00:04]Going to talk about something cool.

[00:00:07]PIDs, that whole section that nobody understands. Well, the geniuses understand it.

[00:00:13]And I try to read what they tell me, but it doesn't make any sense. So, I did kind of a deep dive on it, and I'm going to try to keep this very, very simple.

[00:00:22]Which means I've got to tell some lies.

[00:00:24]So, don't hold me to this.

[00:00:26]But, it's more of a how to think about PIDs, so you know what you're adjusting when you adjust the numbers in your PID parameters. This is purely how to think of it. There's a current loop inside your electric motor. Imagine just uh electricity flowing through that copper winding in a big loop over and over and over again. It's giving the motor current.

[00:00:46]More current, faster. Less current, slower.

[00:00:49]And there's, I guess, a current loop inside the controller, what they call the PID loop. And the controller's reading that current loop at all times in your motor.

[00:00:59]It's got a point it's at. I'm at this point right here on my throttle, and that's where I want to be.

[00:01:04]So, it's happy.

[00:01:06]But, then if I give it more throttle, now there's a point I want to be that's faster than where I was at. The controller has to make a correction to tell the motor to go faster. And that's what the controller is doing. It's doing that via PIDs.

[00:01:22]So, the PIDs are going to tell the current loop in the motor how to react to try to achieve the target that you're asking for. It's going to essentially control speed and torque of that motor. I want you to think of that motor current loop as a angry herd of cattle.

[00:01:42]So, the target is where you want to be.

[00:01:47]We'll call that the feed trough in the other pasture.

[00:01:51]All the cattle are sitting in a field, and they need to get to the feed trough to eat. That's the goal. We're over here, we want to be over there. Well, you got to get the cattle from point A to point B. And to get that rolling and move that current loop to higher amps to increase the current, you got to have a And that comes with a lot of things factor into it. And here's where the lies start.

[00:02:15]Max speed, that setting, that's factored into it. Max amps, that setting, that's factored into it.

[00:02:22]Throttle ACC steps, that's factored into it. Throttle position, that's factored into it. All these things factor into to get that thing going to tell that cattle where to go. And right now we're telling them to go to the feed trough on the other side of the field.

[00:02:41]So, what is PID? Is how, the method we use to get the cattle from point A to point B. It's how we control that current loop in the motor to give us the desired outcome from where we're at to our target.

[00:02:57]The P stands for proportional. That's a proportional component in your PID loop.

[00:03:03]It acts directly on the correction you need to make. If the cows are in the other field, you got to get there, they go immediately to the other field.

[00:03:12]It's an immediate reaction to start the correction of being in the wrong field.

[00:03:16]They're all just going to stampede towards the trough. And even though it's the initial reaction in the PID loop, it's going to happen over and over and over. Cattle are going to continuously want to stampede towards that trough.

[00:03:30]All the way to that trough. If you take the goal or your target and you subtract where we are, that equals the error. The larger that error, the faster they're going to try to stampede towards that trough. So, the P in PID's, think of it as the whip. This is your bullwhip. This is what gets them going. This is the ya.

[00:03:46]You crack that whip, these cattle move and they go into a full blast stampede towards the feeding trough. Problem is these cows are stupid.

[00:03:56]They take off the wrong direction. They don't stop when they get to the feeding trough. They hit the fence after it. All sorts of chaos unfolds as these cattle try to stampede to get their food. The good thing about the proportional whip is it's fast to react. The bad thing is there's a lot of errors in it. Not a lot of control.

[00:04:12]When a rancher moves his cattle, he doesn't want that cattle running the whole way there and in a big stampede.

[00:04:18]He might have 10,000 head of cattle. A running cow can lose a pound running across one field. That's 10,000 lb he just lost.

[00:04:27]He sells that cattle for the pound. So yeah, he wants to keep that cattle under control. He also doesn't want the cattle running so fast they don't stop at the feed trough. Otherwise, they'll hit the fence. Hit the fence and die.

[00:04:40]This is your burned up controller. He also doesn't want cattle getting lost.

[00:04:44]In a stampede, some cattle just head off the wrong way, clueless.

[00:04:48]Run off into the other farmer's field, go off into the trees, never see them again.

[00:04:52]So we need the second component of the PID loop, the I, integral component.

[00:04:58]That is your dogs. These are those cattle dogs. The dogs will correct that herd as they run towards that trough.

[00:05:06]They'll correct it based on history, past behavior.

[00:05:10]Which is observed. Once they observe a error, they'll correct it. So those errors already happened, but the dogs will correct it. As that cow runs off, that dog will bring it back into the herd. As the herd starts steering the wrong way, that dog will bring the front of the herd towards that feeding trough and keep it going towards its target. So the dogs are making corrections for the entire run. The cows are still trying to stampede. The good thing about integral, where the dogs are, they reduce the errors. If you get too many dogs controlling the herd, you end up with a bunch of dogs getting the herd to stop.

[00:05:42]If your KI is too high, the the loop in the motor becomes unstable. Now the herd is just sitting there totally controlled by the dogs. They're controlled nice.

[00:05:52]They're not stampeding, they're not moving. They're just standing there grazing on grass. They're never going to make it to the feeding trough. We've got too many dogs in the pack. We can't have too many dogs. We need something else.

[00:06:02]We need the D.

[00:06:04]Not like that. That's the derivative.

[00:06:07]The D is the cowboy. That's the thinker.

[00:06:09]That's the brains behind the group. The cowboy can prevent future errors. He knows exactly where these idiot cows are going. He knows what they're going to do. He knows they're going to run past that trough. He knows they're going to slam into the fence. He knows they're going to run in the wrong direction. He already knows all this. So he's going to make his corrections based on that. He also knows they're going too darn fast.

[00:06:30]So the cowboy can actually slow the herd. The derivative can anticipate the speed is too fast and slow the herd smoothly to arrive at the feeding trough unharmed.

[00:06:40]He can apply the brakes. The good thing is if you have this cowboy, you have a nice smooth deceleration, nice controlled movement towards the feeding trough. The bad thing is if you have too many damn cowboys, all the cowboys are trying to slow the herd down at different times. One guy thinks they should slow down here. One guy thinks they should slow down there. And you get a jerky abrupt movement of the herd.

[00:07:01]Kind of like one of those hot rod cars that you know takes off, you know, work.

[00:07:05]And you can't control it. It's on and it's off. On and then it's off. That'll be the problem with too much D in your PIDs. So far driver combines the D and the I, the integral and derivative. So I guess when you adjust the I in far driver KI, you're adjusting the integral and derivative both in a combination that it figures out for you. They've combined those two things together.

[00:07:31]Which way to the right?

[00:07:33]I guess that way, right?

[00:07:36]Then you'll also notice it has the KP.

[00:07:38]In some far drivers you'll see KC. And that's your proportional. That's your whip. We can adjust the whip. It appears I can adjust that whip on my Sur Ron controller.

[00:07:50]And I was all excited about that. I was sitting at zero.

[00:07:54]And you can see my drag race here. You can see my quick takeoff here, how high the amps go, about 700.

[00:08:01]And I was like, "Oh boy, I can adjust that whip and I can get a faster takeoff." Guess we'll go to the right.

[00:08:06]Then we'll loop back around.

[00:08:11]So I was all excited and I set my KP to 15 and I went out and did a drag race takeoff and guess what? Same exact phase amps. Oh, we're going to turn around and go down We got to go down that way. So although it makes me think I'm adjusting it, it didn't adjust anything at all. It just lets me think I'm adjusting it. But you can adjust the KI. So what do the numbers mean? I don't know. The FarDriver manual has a guide and gives you some recommended numbers based on motor power, I guess. That gives you a pretty good range of numbers. I've noticed in some FarDrivers you can't adjust certain numbers. I can't get a KI to go higher than four in some FarDrivers, but on some I can put it at six or eight.

[00:08:53]So all we can adjust is KI and then the KP defaults to something based on our KI settings. And then when I have to assume that the KD setting is also self-adjusting with the I. Think of those numbers you see in the parameters as the number of whips and dogs and cowboys you want. If I want to take off faster, I need more whips, more KP. It's not an option though.

[00:09:19]Can't adjust it. Look at KI. We'll combine KI into KI and K derivative. So if I get too many dogs and cowboys, they're going to slow that herd down and make it very smooth. We've never been that way. Go in, I think.

[00:09:33]Oh, yeah?

[00:09:34]Let me check it out.

[00:09:36]So numbers like six through 12, a of dogs and cowboys in there. Makes a very smooth transition to your target. You stab the throttle, it should be smoother. Less room for error.

[00:09:47]Less dogs and cowboys, more room for error. So, you lower that dogs and cowboys down, and you do get a faster and more aggressive takeoff, but you could have more errors. And that would be like your numbers 1 through 5 on the KIs. On those P's, you'll see bigger numbers like 80, 120, but my default is zero at the other end of the spectrum.

[00:10:09]So, big numbers like 40 to 120, that's going to be more bullwhip, faster, more aggressive. Little numbers, less bullwhips, less motivation for the cattle, a slower, smoother response with littler KP numbers. And you'll also notice it's broken down into start KI.

[00:10:27]That's all you can adjust as a KI, so start KI, mid KI, and max KI. I'm going to tell you another lie, cuz I don't know, but I'm going to go with start is off throttle, mid's about mid throttle, and max is when I'm pegged. I'm making that up, but that's where I think the three KIs are and what they apply to. It's still just one interrogating loop of the motor's loop.

[00:10:51]It's one control loop, but as you feed in different portions of throttle, gives you new parameters, it changes your dogs, it changes your cowboys, and it changes the parameters it's going to use to adjust that current loop. Yeah, so hope that kind of made sense. At least that's my understanding of it, and for you experts that do understand it, I know you're laughing.