yup. Right now you simply send too much power (“MOOOOST powerfull board” gives you those issues). So it only needs a 10% input to provide enough power to propel you to max speed.
Or gain weight (hehe) or drop the power (anyway, I suppose you will offer multiple settings, so that will fix itself)
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You’re right. But that’s what we wanna achieve.
& true duty cycle control only approximates speed control when there is no load (ie when the wheels are spinning while your board is upside down)
That’s what we tested.
when someone is actually on the board they will be thrown off when you start to release the throttle and the wheels instantly lock up
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ok, I didn’t know this.
This is not how it should behave.
Please send us screenshots of your app settings.
Which remote were you using again?
If I pull my trigger 10% then my board will use very little power and I would be accelerating slowly until 10% trigger will no longer be able to accelerate me any faster and this would let’s say take me to a steady speed of 15kmph and maintain that with 10% trigger input.
My settings:
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Aparently 30% duty cycle on his setup is enough to reach top speed. It could potentially be possible but I most likely doubt it. Probably an exaggeration of the truth… This can happen at 50-60% though with the right conditions met. If he is carving as hard as he says that he is, it should create enough resistance that he could maintain constant speed without a huge amount of input. Hell, half the time I don’t even use throttle on my board and just carve down hill like I used to do; before I strapped 13kgs of electronics to my downhill setup.
I literally have no idea why you would want this though. Riding the board would be like this haha
You do kind of get use to it with a remote with enough throttle input. The big drawback though with current control is when you lose traction the wheels just spin up faster and lose more traction. Not very safe without traction control imo. With duty cycle this wouldn’t happen because you’re controlling “speed.”
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hmm, have you tried “the MOSSSTT powerfulll” rc car?
maybe those will behave as you’re experiencing with 30% throttle able to max speed the rc car?
30% duty cycle in the controller will only get him to 30% of the rpm equalling kv * battery voltage
if you are referring to the duty cycle transmitted by the remote (a separate duty cycle entirely)… then with his 100a motor current setting, a 30% trigger pull in current control mode should definitely get him to full speed because it equals 30a motor current
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no it controls the voltage the motor sees— 30% duty * 50v battery = 15v to the motor
^the motor sees 15v, so the no load speed is kv * 15v… but the speed of the motor is determined by the load not by the controller’s duty cycle in duty control mode
a 50v battery at 30% duty control is no different from a 15v battery at 100% duty, to the motor—
with a 15v battery at 100% duty (or 50v at 30%), the speed is determined by the load
when 50v * 30% duty = 15v to the motor, and the motor is turning fast enough to produce 25v bemf (4750rpm with a 190kv motor = 190kv * 25v bemf) the motor is producing more voltage than the controller and you get braking, not acceleration
so in duty control mode, when a 190kv motor turns 4750rpm with a 30% trigger pull and 50v battery, you get hard braking till the motor reaches 2850rpm
Wait he is running 100a per motor?? Someone needs to lower their settings…
Thanks, will try it out!
@Friskies I’m not exaggerating at all my friend. This is the problem I want to solve, without lowering any numbers.
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@Chricious can you actually ride the board in duty control mode without someone getting tossed off from unintended braking?
to me it seems you have conflicting goals…
-
speed control without automatic braking
-
duty control without someone getting tossed off
-
as much power and torque as possible but still gentle acceleration
etc…
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Sounds like you want a new control mode that would be a mix of current mode and speed mode.
- when throttle is at X%, it will use X% of your motor current to accelerate you up to X% of your max speed which you either explicitly set / vesc tool calculates it for you
- when throttle is at Y%, where Y < X (what you had before), it will decelerate you down to Y% of total speed, but making sure the reverse torque is not greater than that which you would usually get at Y% of your motor current. (Not greater is important – for most setups it would just cut power and you slowly go down in speed, but if your setup has a lot of friction, where suddenly going into free-roll mode would throw you off, it will mitigate that by still supplying some amount of power)
- to go down in speed faster, you set the throttle to a negative value. The negative values simply determine the percentage of negative motor current that will be applied. I.e., works exactly the same as in current control mode.
I believe that with a setup like this, you can still abuse the power at your hands by full-throttling it when you want, but keeping the throttle at a constant point will keep the board at a constant speed.
@rusins good points…
…so even if the throttle sets the target speed in some sort of cruise control how do you propose to control the acceleration (especially considering hills)? the cruise control in my car decides it for me…
I guess the current just slowly decreases, if the speed goes down, current slightly increases, when the speed is too much the current decreases, and so forth in a negative feedback loop.
I also just remembered that vesc still doesn’t have a torque (Edit: meant to say acceleration, not torque) control mode. I would personally prefer that, because I like the feel of current control mode, but am also sad that on some setups I am limiting my motor amps just to stay on the board. Would really like those extra amps when climbing hills…
since motor current is directly proportional to torque, current control mode is exactly the same as torque control
if you are using watt control, electrical watts are not proportional to torque… constant electrical watts gives decreasing torque with increasing rpm
constant torque and motor current requires increasing watts and battery current with increasing rpms
for constant throttle to equal constant torque at all possible speeds, the motor and battery current limits have to be the same per motor in motor current control mode, not watt control
Sorry, meant to say acceleration instead of torque, whoops. I want an acceleration mode, where on flat it would feel just like current mode, but on hills it could increase the torque even more so that I can maintain the same acceleration, just at higher amps.