When Fred Astaire danced on the ceiling, he was dancing in a specially constructed, rotating room with all the furniture bolted down. The camera operator and the camera were strapped in and down, respectively, and rotated along with the room. The end result was a scene that made it appear that Astaire was dancing on the walls and ceiling.
The rotating set of that scene in the 1951 film Royal Wedding moved in just one direction, around in a vertical circle, or what aviators would call “roll.” Positioning technology for cameras, radar, and robots has advanced substantially since then. Modern positioning devices called hexapods can move an object in six different directions. But exactly what are hexapods, and what industries use them now?
What Is A Hexapod?
“Hex” means six, as in hexameter, hexagon, or hexagonal. A hexapod is a platform that can move a payload (whatever sits on top of the platform) in six different directions. Hexapods usually have six legs, but the name is derived from what’s called the six degrees of freedom of motion the platform provides.
A hexapod (also known as a Stewart platform) can move a payload up and down, forward and back, side to side, and through pitch, roll, and yaw directions. Stewart platforms are not to be confused with hexapod robots, which transport themselves on six legs, mimicking the motion of hexapod insects.
Stationary hexapod robots can work alone or alongside humans in manufacturing. Hexapods work with computer control systems to create precise positions for cameras, workpieces, and scientific tools.
Hexapods in the Automotive Industry
Hexapods and hexapod robots help hold measuring instruments to accurately calibrate headlights and provide precision laser welding for auto assembly. Hexapod robots can move and assemble heavy parts in spaces tighter and at angles more awkward than human workers can, and they do it with repeated precision.
Pilots train in simulators mounted on large hexapods to mimic the motion of an aircraft, including vibrations and sudden, unexpected changes in yaw, pitch, or roll. Usually coupled with a visual display that creates a virtual external environment, hexapods that support flight simulators are an important piece of equipment for pilot training.
Astronomical observations benefit from telescopes that use hexapods for positioning. The ability to adjust a telescope’s position through six degrees of freedom, rather than two, allows observers to more accurately position the light-gathering mirror to point toward the target celestial object or area. Large hexapods can support the weight of large telescopes up to a few meters across.
Spacecraft Repair and Payload Stabilization
NASA’s JPL created the hexapod on the Mars rover, Perseverance. The rover uses the hexapod to position an X-ray instrument to examine Mars rocks more closely. NASA has also been testing ways to service satellites using hexapod robots to simulate refueling or capturing a satellite that needs service when the satellite wasn’t originally designed to be serviced in space. These robots can make minute adjustments necessary to capture a satellite without damaging it.
Scientists, industries, and educators consider several factors when purchasing hexapods to use in research and teaching. Next time you see a robot with six legs or a telescope moving in six different ways, think about what hexapods are and how they’re used in industry and research.