Questions about regen braking (or other types of electronic braking)

[triumph_013]

Hello guys. I am currently in my last semester at Tennessee tech University and my senior project is to add a crash avoidance system to our solar powered Yamaha G2 (I believe this is the model). Is it possible to add regen braking to this cart, or any other form of electric motor braking? If so, this would be the simplest way of getting the cart to stop once it has been given the command to. Plan B is to design something to actuate the mechanical brakes, but with only a semester to do this project I don't believe I will have the time.

Thank you for your help. I will post a picture of the cart once I get it hosted somewhere so I can verify the model with you guys.

Regenerative braking is a method used to make the motor act as a generator to governor the golf cart’s speed to a preset rpm, as well use the power generated to slightly recharge the batteries. Thus the need to know the motor rpm is evident so the controller can control such features.

The roll away feature is purely for safety. If you forget to set the parking brake on your golf cart and it starts to roll away, this feature will limit it to only be able to roll in neutral at a preset rpm, which is usually the equivalent of under ½ a MPH or so. This allows you to easily catch up to the cart before it crashes into something causing major damage

i do not think a Yamaha G2 can be upgraded to a regen brake system

plan B sounds best

[cgtech]

If it is purely solar powered (no batteries, just solar), regen, which only applies "sepex motors", is a more complicated as there is nowhere to put the regenerated power. That would require a "burn off resistor" and a system to direct the power to it. What about instead a series controller with a A2 terminal for "plug braking" with a f&r contactor array to be able to "flip" it into reverse when the automatic braking feature is activated. This idea ought to work on a "pure solar" system because all the energy is burned in the controller, not returned to the energy source. The "plug brake" system is designed to safely stop vehicles that are likely to be shifted into the opposite gear while in motion.

[triumph_013]

It is not a purely solar system. The cart can still be charged via the original charge port. The solar panel just offers additional charging. I'm still waiting on the report from the previous teams so I can have a better understanding of the system, but the batteries and original control systems look untouched.

I have read about plugging, which seems like a more viable option for an emergency stop, but I have also read that some electric motors are not designed to be able to handle the extra heat associated with this method. I don't want to break the cart haha. Can the motor in this cart handle it?

[cgtech]

The stock motor (GE) has brushes that are not huge (IE: dont love huge heat)... But, if your control system is stock (Resistor Coils), you are SOL, there is no way to safely implement Plug braking with that setup. How often do you expect the "auto braking" system to engage? Like regular driving brake usage, or only the occasional panic stop to avoid an accident?

cgtech is the guy

you need to pick his brain

plan B ...you could use a 12v actuator hooked to brake arm and powered by your crash avoidance system



like this

[triumph_013]

Originally Posted by cgtech

The stock motor (GE) has brushes that are not huge (IE: dont love huge heat)... But, if your control system is stock (Resistor Coils), you are SOL, there is no way to safely implement Plug braking with that setup. How often do you expect the "auto braking" system to engage? Like regular driving brake usage, or only the occasional panic stop to avoid an accident?

Only the occasional stop when the system senses an obstacle. Your post brings me to another question I had that I was planning on making another thread for, but can I convert it from the resistors to a PWM setup? I can easily control the voltage to the motor through PWM if I get the right board. How much voltage does the motor need?

Originally Posted by crash test dummy

cgtech is the guy

you need to pick his brain

plan B ...you could use a 12v actuator hooked to brake arm and powered by your crash avoidance system



like this

Sounds like a good plan B. The main reason I would like to control the braking through the engine is so that it can have different levels of braking at different speeds, and possibly even be able to follow a cart in front at a predetermined distance. If I can figure this out though, then I will be using an actuator on the pedal.

[cgtech]

The Alltrax SPB (series, like yours), or XCT (sepex motors with regen) support throttle control by USB. Yours could be converted to Solid State controller easily (but costs $). Both support a 0-5k ohm throttle input, which your current throttle wiper (the part which sends power to your current resistor coils) could easily be converted to. Making your own PWM board for motor control is very do-able, but it must support 36v AND about 300a current.

[triumph_013]

Originally Posted by cgtech

The Alltrax SPB (series, like yours), or XCT (sepex motors with regen) support throttle control by USB. Yours could be converted to Solid State controller easily (but costs $). Both support a 0-5k ohm throttle input, which your current throttle wiper (the part which sends power to your current resistor coils) could easily be converted to. Making your own PWM board for motor control is very do-able, but it must support 36v AND about 300a current.

Yeah I doubt I can find an Arduino board that can handle that much, but I may be able to go from the Arduino to another controller. The plan is to use an Arduino along with a LIDAR sensor to control everything. I may be able to use PLCs but that would increase the budget.