Comparing Wheel Speeds for Traction Control

[lakmalp]

Hi,

I am experimenting with traction controlling of wheels. I have to calculate the speed difference in two wheels (driven and non-driven). I am thinking of these options:

1. Generate pulse train using optical encoder -> binary counter -> D/A converter -> Take voltage difference using OP amp -> do processing in uC based on the voltage produced by OP amp.
2. Use of a DC motor (in this case a generator) to generate voltage corresponding to the RPM -> Take voltage difference using OP amp -> do processing in uC based on the voltage produced by OP amp.

I have attached a schematic of my project as a pdf to this thread.

Please advice me as to what option would be most accurate or are there any other ways I can accomplish this.

Regards,
/Lakmal

 

[anorlunda]

Beyond a doubt, the optical encoder is more accurate. You do not need just a magnetic pickup, you can get a high precision angle readout from the optical encoder.