Throttle Problem 1-4v hall to PWM

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Throttle Problem 1-4v hall to PWM

Postby Keith_hill » Wed Nov 30, 2016 4:52 pm

Hi All,

I was hoping that someone could shed some light on to a problem I'm having with my throttle.

My throttle set up is this:

Throttle: http://alienpowersystem.com/shop/electr ... ll-effect/
PWM Chip: http://alienpowersystem.com/shop/rc-ev- ... face-1-4v/

ESC is: http://alienpowersystem.com/shop/esc/al ... et-esc-hv/

The problem is 100% of the power is applied at about 50% of the available thumb throttle travel, this means that it is difficult to modulate - this can be seen in the video I posted of my build. So when riding it, after 50% of the throttle is applied the scooter seems to be going as fast as it can and the rest of the throttle travel is just dead.

I checked tonight that the hall effect throttle is indeed a 1-4v output (thought that it could be a 0-5v by mistake) but the multimeter confirmed the spec.
Would this happen if the PWM chip was actually the 0-5v version by mistake?

Has anyone encountered anything like this?

- Keith
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Re: Throttle Problem 1-4v hall to PWM

Postby made_in_the_alps_legacy » Thu Dec 01, 2016 1:28 pm

I am concerned by your ESC actually ("jet ESC" ?) I see "THROTTLE CURVER: Logarithmical、linear、Exponential", which setting do u use for this parameter ?
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Re: Throttle Problem 1-4v hall to PWM

Postby Keith_hill » Thu Dec 01, 2016 2:29 pm

Hi, I am currently using 'Linear', however I have tried using 'Logarithmic' but I still only had 50% of the thumb throttle travel available.
The firmware for the ESC is actually called 'CAR 12S'.

Do you know what these settings are for:

FORWARD POINT:Auto、fixed 1.0mS、fixed 1.1mS、fixed 1.2mS、fixed 1.3mS、fixed 1.4mS, fixed 1.5mS

Regards

Keith
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Re: Throttle Problem 1-4v hall to PWM

Postby made_in_the_alps_legacy » Fri Dec 02, 2016 12:58 pm

I believe "linear" is better than "logarithmic" with respect to ur issue, I think it-s risky to try "exponential" but who knowes...
this "forward point" adjustment makes me think about the minimum speed when your throttle just leave its neutral range.
Maybe better ask directly alien power about ur issue, about a potential PWM chip mix
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Re: Throttle Problem 1-4v hall to PWM

Postby Keith_hill » Sat Dec 03, 2016 10:50 am

Yes, Linear is far easier to ride.
I have asked Alien Power Systems about the issue but Bruno apparently can't help me - a little frustrating!
Thanks for your help, I wonder if there is a problem with the ESC not being able to identify the range of the input because it is hard-wired? usually you cycle the stick of a remote control to allow the ESC to see the range of signal (I think I'm right??)

I'll keep researching.
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Re: Throttle Problem 1-4v hall to PWM

Postby made_in_the_alps_legacy » Sun Dec 04, 2016 4:09 pm

whatever your input system to the esc is, you must still be able to make a "throttle range adjustment" procedure
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Re: Throttle Problem 1-4v hall to PWM

Postby saul » Mon Dec 05, 2016 1:57 am

you should be able to calibrate your esc with the input.

it could also be the hall sensor throttle does not "use" the full travel.
or the interface circuit is crap.
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97mm Fly wheels + tiny 85kv + 12s Vesc
https://endless-sphere.com/forums/viewtopic.php?f=35&t=76450

more to come...
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Re: Throttle Problem 1-4v hall to PWM

Postby Keith_hill » Mon Dec 05, 2016 5:47 am

I've come to the conclusion that the interface chip isn't working correctly. Seemingly is uses 2v as 100% output. The throttle outputs 1-4v correctly and the ESC works correctly when connected to a RC car receiver.

I have told alien power systems that's where the problem is - let's see what they say!

Perhaps this is an opportunity for my to practice my arduino skills??


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Re: Throttle Problem 1-4v hall to PWM

Postby saul » Mon Dec 05, 2016 12:32 pm

Keith_hill wrote:Perhaps this is an opportunity for my to practice my arduino skills??


I was going to suggest this but wasn't sure of your background. It would be a very simple setup.
i'd use a trinket/digispark or something similar. you only need 1 analog and 1 pwm 8)
Builds:
97mm Fly wheels + tiny 85kv + 12s Vesc
https://endless-sphere.com/forums/viewtopic.php?f=35&t=76450

more to come...
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Re: Throttle Problem 1-4v hall to PWM

Postby Keith_hill » Mon Dec 05, 2016 6:17 pm

My background is mechanical engineering. This project is to broaden my electrical knowledge (motor sizing and control etc) I have an arduino to play with so I'll get to it! Should be simple as you say - however I'll be learning as I go!


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Re: Throttle Problem 1-4v hall to PWM - Solved

Postby Keith_hill » Mon Jan 23, 2017 3:21 pm

As I mentioned in my main scooter build - I have solved my throttle interface problem.

Here is the thing I have ended up with, it is Arduino nano based and has a rotary POT which is set to alter the maximum servo angle PWM output. it is really useful when letting someone have a go and slowly build up the 'power' level. I also find that I set it to 50% for using the scooter on pavement around people etc..

I have also set a 30ms count up for throttle output vs. throttle demand. It helps with the initial power take-up as the ESC is simply requesting the motor to hit a requested speed with 100% current. (fine for an RC car but a bit chaotic when stood on the blood thing!)

I'm going to shrink it down when I manage to get a digispark to correctly handle servo output. the whole thing will be about half the size.

throttle_interface.jpg
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Last edited by Keith_hill on Mon Jan 23, 2017 3:28 pm, edited 1 time in total. View post history.
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