Drivetrain and Chassis (2021-2022)

Owned by
Mathieu Harter (Deactivated)
Last updated: May 11, 2022 by
Emily Adam
3 min read

Revision 1: S22 - Present

About

The goal with designing this rocker-bogie drivetrain is to create a system that passively overcomes rock and boulder fields, soft sandy areas, and steep slopes while keeping as many wheels in contact with the ground as possible. This improves the rover's stability during traversal. In addition, this style of drive provides the rover with more traction while scaling obstacles.

Revision 1 of the design features the following...

  • Balloon tires to dampen vibrations and cushion the system from shock
  • 6 brushless DC motors each integrated into a 35:1 ratio VersaPlanetary gearbox, in a direct transmission with the wheel
  • Motor & gearbox integration into the balloon tires to protect them from the elements
  • Differential bar on the underside of the chassis as to not interfere with the upper assembly
  • An aluminum frame, due to lack of access to carbon fibre at the time

Photos

  • Important note: the mounting plate shown in the image above is only used for mounting the arm. That plate will come off entirely to mount the science mechanism

Bill of Materials

Uploaded on May 9th, 2022

  • Note: fasteners listed in BOM were often replaced with equivalent ones sold at the EMS store, unless they were specialty

Important OTS items


Known Issues

Unresolved (i.e. no solution in place yet)

  • Lack of stiffness in the differential bar amplifies into larger play in the chassis
    • One contributor was observed to be the tolerance of the pinhole on the ball joints
  • Lack of robustness for the encoder magnet to the motor shaft connection
    • Currently, the magnet is just superglued on. But because the magnet is tall and skinny, if nudged by the walls of the encoder, it could pop loose

Resolved