Stuart platforms are quite neat, and not often seen in wild areas, probably because there aren’t a huge number of hacker-friendly applications that require so much degree of freedom within such limited range of movement. However, here is an interesting implementation from the curiously named [Circular-Base-Stewart-Platform] One with the YouTube channel (no, we can’t find the designer’s real name) A series of videos from a few years ago, showing the construction and operation of such an animal. It is a very neat mechanism consisting of a motor with six gears at the end of the weapon, involving a large internal gear. The common edge of each arm climbs over the central canyon, each with its own bearing. A complete platform is realized with the addition of six common connections, twelve ball joints and a few brackets.
This circular format is so simple that we can’t believe we haven’t seen it before. An interesting deviation from the normal Stuart platform layout is the use of a central slip-ring connector to provide power, which allows the process to rotate the whole assembly continuously, in addition to the usual six degrees of freedom. The controls are courtesy of an Arduino Pro Mini, which runs the motor using some Pololu TB6612 (PDF) dual H-bridge driver modules. Obviously, running sketches in Arduino will give the thing a steady momentum, but add an extra data link (or perhaps a wireless link) to that central slip-ring setup, and it will be much more effective.
We recently saw another 6-DOF actuator design, using Flexer, another ball-balancing hack, but if you really want a useful Stuart platform app, check out this pool-playing robot!
Thanks [quibble_droid] For the tip!