Use of Motors and the Drive

Date: May 4, 2018

Members Attending: Alexis, Eylert, Kira, Lynn, Robert

Mechanism: Drive, Overall Robot

Todo: Build drive chassis

Today we discussed our driving chassis and how many motors we want to use.


Thus we should be able to use 4 motors for driving. However two of them could also be used in our fuel-cube mechanism. That is why we decided to calculate the RPM and torque for several configurations and compare them with last year, to get a feeling for which one fits our requirements most.

Motor specs:

  • Core Hex Motor: RPM: 125 Torque: 3.2Nm HD
  • Hex Motor: RPM: 150 Torque: 4.2Nm
  • HD Hex Motor 20:1 Gearbox: RPM: 300 Torque: 2.1Nm

Formulas used for calculating torque and rpm with motors and gear ratio:

  • torque = torque_without_gear * motors / gearratio
  • rpm = rpm_without_gear * gearratio
Motor (always 2 pc)GearRPMTorque in Nm
Core Hex1:11256.4
Core Hex3:13752.13
HD Hex 20:11:13004.2
HD Hex 20:14:34003.15

Last year we drove relatively well, however we had trouble going up the ramps. This year there is no ramp to go up. Thus we do not have much need for torque. On the other hand, our robot will most likely weigh more, thus needing more torque to move. We think the best balance will be using two HD Hex Motors and gearing then 4:3. We plan to use chains and sprockets instead of toothed gears, because sprockets are better for high torque applications, whereas gears are good when going for speed.

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