this is a synchro drive mechanism that can be used to propel a robot in the xy-plane. the mechanism cannot rotate the robot about its vertical axis. two motors are needed, one to drive the robot and one to orient the wheels. two nema 17 stepper motors and two tb6600 driver have been used for this purpose. an arduino uno controls the motion. the drive can either be piloted via a radio controller or it can follow a predefined path automatically. most parts are 3d printed in pla. the plates are laser cut from poplar plywood since they are a bit large for my 3d printer. several additional components (motor, motor driver, arduino, aluminum flanges, ball bearings, hi-bounce balls, etc. i got from aliexpress and other sources. more information on the project can be found here: https://www.muellerr.ch/synchro-drive-robot/ two videos of the drive in action can be seen in the following videos: