Emergency braking concept for VESC

General topics and discussions about the VESC and its development.
rew
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Location: Delft, Netherlands.

Re: Emergency braking concept for VESC

Postby rew » 06 Jul 2017, 06:32

See: http://www.bitwizard.nl/shop/BitWizard-ESC?search=besc

The last two images are of the power board. That has the current sense resistors. I have three of them preparing for three phase-current-measurements.

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Ecyclist
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Joined: 24 Jun 2017, 01:26
Location: San Diego, CA

Re: Emergency braking concept for VESC

Postby Ecyclist » 30 Sep 2017, 15:38

Hi guys,
I'm building e-bike and using VESC to control 6374 motor. Can you tell me if it is possible to temporary cut power from VESC to a motor?
I would like to attach hall sensor to brakes and use a signal from sensors for that.
This can be done with the help from CA3 (Cycle Annalist 3), but I'm hoping that I can do it directly with VESC.
You can see my thread about my build here: https://endless-sphere.com/forums/viewt ... =3&t=90432
I posted this question on my build thread, but so far no luck.

rew
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Joined: 25 Mar 2016, 12:29
Location: Delft, Netherlands.

Re: Emergency braking concept for VESC

Postby rew » 01 Oct 2017, 09:09

Hall sensors are not able to assist in breaking. As the word "sensor" says they sense something. They are not active.

In order to brake, all you need is to rectify the phases from the motor and use a variable resistor to load the resulting (not quite) DC.

You don't need to disconnect the VESC to do this. It would be wise to instruct the VESC not to power the motor during all this as that would defeat the purpose.

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Ecyclist
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Location: San Diego, CA

Re: Emergency braking concept for VESC

Postby Ecyclist » 01 Oct 2017, 20:31

I was not clear if comes to the hall sensors. You can buy a brake hall sensor switch that you attach to the bicycle brake. This is not the same as the motor hall sensors. The brake hall sensor works on the same principle. A small magnet is attached to the brake lever, and sensor is in a fixed position. Once the lever is moved, there is a change in magnetic field, and the sensor sends a signal to the controller. Controller processes the signal and temporarily cuts the power to the motor. This can be important if something went wrong with a throttle or in emergency situation. Some people call it DEAD MAN SWITCH. I'm not interested in theories or ideas. I know that this can be done easily by someone with programming knowledge. Has anyone done it with VESC? How do I go about it? I'm hoping that this is as easy as connecting the hall throttle.

pf26
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Location: FR Valence

Re: Emergency braking concept for VESC

Postby pf26 » 03 Oct 2017, 06:44

To my knowledge, there is no DeadMan switch input implemented the way you want (for Vesc4, I don't know much about 6)
But in the app_adc application (which you probably use for the throttle), there are 2 input buttons available, one for rev (=Rx), one for cruisecontrol (=Tx). You could change the adc application to use the cruise control input as a DeadMan switch input. Something like adding:
if (cc_button) current_out=0; before each implementation of: mc_interface_set_current(current_out);
You need to have a close look in app_adc.c

rew
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Joined: 25 Mar 2016, 12:29
Location: Delft, Netherlands.

Re: Emergency braking concept for VESC

Postby rew » 03 Oct 2017, 07:41

As far as I know, that's already implemented. If you don't want the VESC assisting in braking but just cutting power when you activate the switch (*), you should set the max battery reverse current very low.

(*) Just call it a switch, the fact that it is hall-sensor based does not matter in this case!

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Ecyclist
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Location: San Diego, CA

Re: Emergency braking concept for VESC

Postby Ecyclist » 04 Oct 2017, 23:57

Guys, thank you for your replies. It looks like it is doable. Unfortunately I just joined the world of VESC and I could use some help.
Can you do step by step instructions?

ThierryGTLTS
Posts: 80
Joined: 09 Aug 2017, 11:10

Re: Emergency braking concept for VESC

Postby ThierryGTLTS » 05 Oct 2017, 07:03

Just have a Look there

http://vesc-project.com/node/186

It's a new (yesterday) step-by-step set-up :!: :!: :!:

Have a Nice Day.

Thierry

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Ecyclist
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Location: San Diego, CA

Re: Emergency braking concept for VESC

Postby Ecyclist » 07 Oct 2017, 15:35

ThierryGTLTS wrote:Just have a Look there

http://vesc-project.com/node/186

It's a new (yesterday) step-by-step set-up :!: :!: :!:

Have a Nice Day.

Thierry


Thank you Thierry :!:
At this point the link is not working but I will keep trying.

ThierryGTLTS
Posts: 80
Joined: 09 Aug 2017, 11:10

Re: Emergency braking concept for VESC

Postby ThierryGTLTS » 07 Oct 2017, 16:51

Hi Ecyclist,

I've seen on "endless Sphere" the fantastic job you've done with the cycloïdal drive.

My Project will couple a TMotor U8 to a 12:1 Neugart reducer and then a 3:1 sprockets and chain reducer with a freewheel.

But I have a question if you wanna use a PAS, how will you interface it to the VESC :?: :!:

Have a Nice W-E.

Thierry


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