Robot: ProtoBot

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ProtoBot Foundations...

This robot has odd origins... I needed a test platform for the high power H-Bridge design I have come up with for the Sojourner robot project. Given that the Sojourner robot project has 10 of these integrated into a single design I thought it best to design and build a single functional module with which to test. Given that I have some motor / gearbox combinations here in the studio for use in a different project, a coworker of mine suggested that I produce a pair of the new amplifier boards, clamp the whole mess to a piece of plywood and test drive it around the studio floor.

Of course there are a number of other functions I need to integration test and if I am going to develop the PID functionality on this platform, then I'll need to integrate the IMU and several other functions. At this point the reader may be thinking feature creep, and that is exactly what this project is... It is a fun string of feature creep that turned a high powered motor driver board into a fully developed robot.

There is a lot more to share about tasks and foundations, and since this project shares a common lineage with the Sojourner robot project (below) I encourage the reader to follow on on page 00 of that project.

Overview:

Iso-Views:

ProtoBot exists as a simple 4 wheeled robot with differential steering and no suspension components. Differential steering is implemented through the use of #35 stainless steel chain connecting the gearbox output to both wheels at the same time. As the structural plates are designed to be extremely simple to make they could just have easily have been cut from wood on a table saw. The only reason for the extensive lightening holes and extra material removal is to lighten the overall chassis.

The mast is a derivation of several previous designs and observations of armature roboticists who's work proceeded me. Their observations show magnetic effects of the fields of motors and other radiated EMI fields on stationary fields like the earth's magnetic field thus influencing the readings of magnetic compassrd and IMU's like the one by micro-strain that I will be using. Rather than spend a large amount of time shielding all of the various components it is much easier to merely separate the components with physical space. Additionally, the adjunct of the mast allows for the separation of the antenna of the two independent radio systems to keep their internal heterodynes from interfering with each other.

References:

For those following the development of the robots on this site, the following outlines a short list of must visit related web sites.

Simplified ProtoBot Isometric Overviews