You are here

What is the best way to make an emergency button to stop the motor from spinning?

6 posts / 0 new
Last post
kdomanski
Offline
Last seen: 7 months 2 weeks ago
VESC Free
Joined: 2019-04-16 22:22
Posts: 5
What is the best way to make an emergency button to stop the motor from spinning?

Hi,
what do you think is the best way to integrating the emergency switch with VESC? I want to make a robot and when it goes out of control safely stop it with an emergency push button. I can think of few solutions, for example, when the button is pushed send a command to the vesc to set velocity to zero but what if vesc in itself will malfunction would it be better to cut off the power from vesc?

skyline1970
Offline
Last seen: 12 months 1 day ago
VESC Free
Joined: 2017-09-07 22:28
Posts: 232

drv's en_buck pin could be connected to gnd, or better motor supply could be breaked via a selenoid contactor

kdomanski
Offline
Last seen: 7 months 2 weeks ago
VESC Free
Joined: 2019-04-16 22:22
Posts: 5

I thought about relay but is it safe to cut off the esc from power immediately and even if it is then after the cut off would the motor spin freely or would it be stopped?

Duane Degn
Offline
Last seen: 3 years 1 month ago
Joined: 2020-08-01 02:54
Posts: 14

The kinetic energy of the spinning motor and wheel have to be converted to some other form of energy in order for the motor/wheel to stop. The VESC normally converts the kinetic energy into electric energy by dumping power back into the battery. If you're not going to convert it to electric energy, then you'll likely convert it to heat. You can convert it to heat by using some sort of physical brake.

If the VESC is malfunctioning then you'll need some sort of physical braking system. Stopping just a spinning motor shouldn't be too hard but stopping a spinning motor and an adult human will require a substantial braking system.

Duane Degn

kdomanski
Offline
Last seen: 7 months 2 weeks ago
VESC Free
Joined: 2019-04-16 22:22
Posts: 5

Ok, thank you both for the responses. I have one more question. In vesc 6 MK V there is power on switch, could you tell me if is it possible to switch off the vesc when the motor is spinning? 

skyline1970
Offline
Last seen: 12 months 1 day ago
VESC Free
Joined: 2017-09-07 22:28
Posts: 232

May not be a good idea to shut-off lower mos switcher, the best option is to switch-off  DRV's and next turning on additional low side mosfets on phase arms. These transistors could have a series about 0.5 R high wattage resistors.