Back when the SGVHAK rover started, we started literally from the ground up by building the wheels. The wheels were one of the more significant differences from the baseline rover design and we wanted to get a head start on problems.
Once the initial parts of the planetary gear hub for rover wheel were 3D printed, we started to get an idea of how well things fit our target design constraints: All of the 3D printed parts must fit between two non-3D printed components. On the outside: the tire (and foam tire insert) of a remote control monster truck. On the inside: an electric motor.
The space constraints pointed us towards a planetary gear as the best approach for the reduction gear in this drivetrain. In addition to the planetary gears, the space must accommodate the components for a rotary encoder so we can set up a closed loop motion control system for wheel motion. We don’t just want the wheel to turn – we want it to turn at specific rates, to reach specific positions, and we need an encoder to close the feedback loop on what the wheel is actually doing.
Once all the mechanical bits are assembled, it will be time to hook it up to the motion control circuit. We’ll be using RoboClaw boards from Ion Motion Control for this project.