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Slot car ESC?

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adrianblakey
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Joined: 2022-10-13 11:01
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Slot car ESC?

Could VESC be used as a brushless motor controller in a slot car? If so, what would be a good hardware solution and what software updates would be needed?

There is a lot of interest in the slot car community in using brushless motors. They have many advantages over conventional brush motors. https://www.slotforum.com/threads/brushless-slot-car-racing-association.... and (if you must) https://www.facebook.com/groups/308254371195488 It's being held back by lack of a widely available solution that could be solved by open source.

The physical requirements of the ESC are:

  • Drive a 1106/3800KV or 1108 motor.
  • Be very small and light - say a few grams, ~15mm x 15mm x 1mm, so it can be attached to a 1/32 scale slot car and the package standardized, so chassis can have a space for the ESC.

Electrical requirements are:

  • No control signal from a flight controller - there isn't one.
  • Varying input voltage 0-13.5 vdc.
  • Current (?) maybe a few amps ...
  • Fast switching and processing. A slot car can de/accelerate very quickly (~3G) and reach a max velocity of say ~100 feet/sec

Firmware requirements are:

  • Translate an input voltage into a motor speed. (linearly or based on a "curve"/table lookup).
  • Stop the motor "dead" if it's rotating when the input voltage drops below a specific value.
  • Accelerate to full power and full speed on reaching maximum input voltage.
  • Dynamically calibrate the lowest and highest available voltage to "full on"/"full off".
  • Intermediate in acceleration and braking by applying "curves" so that input voltage changes don't linearly correspond to motor speed and power.
  • Apply "programs" to alter the overall characteristics of the controller (for different tracks and cars) to mimic how a race car is driven (hard brake into a corner, trail brake, balance on throttle, apply throttle, full throttle).
  • A simple UI for programming the ESC (nice if this was available when the car was parked/stationary but receiving say <=3.3v over bluetooth/nf)

Modern transistorized slot car controllers (http://www.slotcarracing.org.uk/control/cont1.htm) have sophisticated control over the DC voltage and current that is fed to the track for creating the effects that are required of the firmware described above. There are a few controllers that use PWM that obviously are incapable of providing DC and outside of scope. So it's possible to tune the controller to provide a quiescent amount to power to the track that would be enough to activate the ESC but be interpreted by the ESC to mean "stopped".

What's the path to get something going?

  • Choose a chip?
  • Design a simple board?
  • Make it?
  • Program it?
  • Test it ...

 

frank
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The VESC 6 EDU without housing would be an option. 3800KV is a bit too much for FOC control. The PCB would need to be re-designed to be even smaller.

A VESC 6 EDU would need a stable voltage supply (for example 8-25V) and get the control signal via bluetooth or PPM or ADC or CAN. You can't control it with the input voltage!

You could control a simple DC motor with the VESC 6 EDU if it is not inside the car but instead it is used to power the track. But that is probably not what you are looking for.

https://trampaboards.com/vesc-6-education--c-2335.html