Sawppy the Rover
Sawppy is a motorized model of Mars rovers Curiosity and Mars 2020. It faithfully reproduces the Rocker-Bogie suspension kinematics of real rovers and is intended to be a hardware platform for future software projects in autonomous operation. Go forth and boldly explore the back yard, Sawppy!
All information for building Sawppy is free and public open source for anyone to build their own. Build instructions can be found under the docs subdirectory.
Sawppy the Rover was inspired by JPL's Open Source Rover project. Most of the differences between Sawppy and its JPL inspiration were motivated by a desire to reduce cost and complexity. JPL's rover is designed for education, to be assembled by a school team and give a robust foundation for structured curriculum. Sawppy is more suited for individual hobbyists like myself who are happy to tinker and willing to make some trade-offs to lower cost.
The budget was $500, and getting there required the following changes:
- Motorization: Instead of using gearmotors with encoders managed by RoboClaw motor controllers, moving the wheels will be done with serial bus servo motors. For more information on these devices, please see this article on Hackaday.com.
- Construction Method: Instead of using the Actobotics construction system, Sawppy will be built from Misumi HFS3 aluminum extrusions connected by 3D-printed plastic parts. For more information on this construction technique, please see this article on Hackaday.com.
These two major design goals can be summarized as: Servo Actuated Wheels, Printed Interconnect For Extrusion. The acronym SAWPIFE led to the nickedname "Sawppy".
Sawppy is at version 1.0!
This milestone includes a motorized rolling chassis that is mechanically functional. The remaining areas (electrical, software, etc.) are still very immature, just barely enough to validate mechanical chassis function. Click this image for a YouTube video illustrating the chassis in action, climbing a backpack that is almost double the height of wheel diameter.