Hexapod 6-DOF parallel kinematics precision positioning systems (Stewart Platforms) are ideal supports for fast steering mirrors. They can provide the coarse alignment (coarse meaning sub-micron resolution) to compensate for out of focus deviations. Even though usually only 5 degrees of freedom are required, hexapods are the preferred solution due to their high stiffness (low vibrations), symmetrical design, and large central aperture, allowing light to pass through. PI has 40 years of experience with parallel kinematic structures and delivered the first high precision hexapods for astronomical applications in the early 1990’s. Today, PI provides more standard precision Stewart platforms than any other company in the world.
PI supplies 50 custom, weather-proof hexapods. The Alma telescope array was a major contributor in the first imaging of a black hole.
- Linear travel x/y/z: ±35/±35/±30mm
- Rotational travel u/v/w: ±7/±7/±9.5°
- MIM: 2µm
- Repeatability x/y/z: ±5µm
- Velocity: 2mm/s
- Protection class: IP64
- Load capacity: 750N (any direction)
"Planetary Imaging Concept Testbed Using a Recoverable Experiment-Coronagraph" - High Altitude Balloon Mission
The mission's long term goal is to directly image Earth-like planets around nearby stars. The telescope was carried by a 39 million cubic feet helium balloon to the outer edge of the atmosphere at 125,000 feet, more than 4 times the height of Mount Everest.
An H-811 miniature hexapod was used in the optical control system. The picture shows electric heaters and sensors applied to the hexapod legs to keep it operating at the extremely low temperatures at the edge of space.
The slitless spectrometer in the WFIRST wide field instrument is based on a compound grism (grating prism). A compact hexapod was used for the alignment and test of the elements in the grism assembly. More information»
Pan-Starrs-1 is one of four 1.8m Telescopes on Hawaii; the M2 is equipped with a custom PI hexapod.
Magdalena Ridge Observatory, located in New Mexico, the 2.4m Telescope is equipped with a custom PI hexapod.
Skymapper is a 1.3m Telescope in Australia, also using a PI hexapod.
