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Ridgebotics

Drivetrain

Guide 6

The carpet sets the limit. Wheel grip is robot weight times tread friction. A well-geared drive slips before the motors reach their current limit.

Who wins a pushing match

Example inputs; the calculator updates these with yours. Imperial first, metric in parentheses.

Motors push: 135 lbf(600 N at 60 A)137 lb robotGrip available: 150 lbf (669 N)Motors hit 60 A first: 15 lbf of grip unused240 A total = 200% of the 120 A main breakerotherrobot
appliedcalculatedwatchfailure point

Example inputs from the calculator defaults. Losses ignored.

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Wheels slip before motors stall, so traction sets the real load

  • Inputs
  • Joint
  • Calc
  • Check
  • Motor type and motors per side
  • Current limit

Drive motors

  • Motor torque at limit and stall
  • Free speed
  • Calc
  • Gear ratio, all stages
  • Swerve or tank

Drive reduction

  • Free speed
  • Wheel torque at the limit
  • Calc
  • Wheel diameter
  • Tread friction coefficient

Wheel

  • Wheel hub torque at slip
  • Hub bore pass or fail
  • Check
  • Mass with bumpers and battery
  • Driven wheels

Robot

  • Traction-limited push
  • Current-limited push
  • Calc
  • Main breaker budget
  • Pushing match length

Pushing match

  • Slips first or stalls first
  • Total draw vs the main breaker
  • Check

What it teaches

The weakest link isn't always a part. Sometimes it is physics outside the robot.

Session hook

Push test against a scale or another robot, and compare it to both predictions.

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