DEWBOT XIV Drive Train

From DEW Robotics
Revision as of 03:34, 20 March 2018 by MaiKangWei (talk | contribs)

Jump to: navigation, search
CVT swerve 2018.jpg
Sab-BOT-age's swerve focus for 2018 was to enable straight and accurate driving, in both autonomous and teleoperated modes. Accurate driving and navigation in autonomous was quickly identified as a critical performance requirement for FIRST Power-Up.

CVT swerve, first employed in DEWBOT XIII, was again used for the 2018 robot.

Motors

A CIM motor provides the drive power for the wheels.

Our old standard steering motor, the BaneBots RS540, is no longer on the FRC approved list. It was replaced by the AndyMark 9015 motor (am-0912) at a weight penalty of 0.16 lbm. This motor is mounted on a BaneBots P60S-555-5 132:1 reduction gearbox (same gearbox used since 2013).

The belt tensioning servo is a Rev Robotics Smart Robot Servo (REV 41-1097). Its metal gears provide good durability.

Other Developments

  • In 2013, the very heavy 1" top flanged bearing (McMaster 6384K373)
    25mm 6805-2Z bearing and printed holder
    was replaced with an Igus polymer bushing and a bronze sleeve. This arrangement occasionally failed either in having the Igus bushing become unseated from the module top plate or through increasing rotational friction. In 2017, this was replaced once more with a bearing, but a much lighter, 25mm bearing (6805-2Z) with a printed bearing retainer. The top of the steering tube is turned down accordingly and a boring head was used to assure the bearing's proper fit in the modules' top plates. So far, this has been a positive change with no issues observed. The original 1" top flanged bearing (McMaster 6384K373) remains in service in the bottom position.
  • There's a new encoder scheme: a Hall-Effect sensor employed as a tooth sensor under the 3.5" pulley. This is not satisfactory.