The M-811.STV is PI's smallest standard vacuum-compatible Hexapod. Despite its size it can handle loads up to 5 kg (2.5 kg in any orientation) and achieves velocities up to 10 mm/sec. With a diameter of only 130 mm and a height of 115 mm it provides travel ranges up to 35 mm in the XY-plane and up to 13 mm in the Z-direction. In combination with the large tilting angles of 20° around the X and Y axis and up to 40° around the vertical axis it allows for complex motion profiles with particularly flexible placement of the load – a great advantage in restricted areas (such as beam lines) and small vacuum chambers.decade. PI Hexapods were originally used in astronomical telescopes for mirror and antenna adjustments over wide ranges in small step sizes. The M-840 provides six degrees of freedom with 3 µm minimum incremental motion (combined 6-axis move, design-resolution of individual struts is 0.016 µm for the M-850.5DG) and allows the user to define the center of rotation (pivot point) anywhere inside or outside the system. The M-840 Hexapod is of great value for any complex, high-accuracy positioning and alignment task where independent motion in six degrees of freedom is required.
Fast Positioning in Space Compared to the M-850 Hexapods, the M-840 is built for higher speeds with lower loads. Up to 10 kg in any orientation can be moved at with up to 50 mm/sec (600 mrad/sec) true path control. The control system automatically manages its path planning and the coordination of the six motors and minimizes runout and unwanted motion.
6-DOF Parallel Machines The M-840 Hexapod consists of six struts which expand and contract between a bottom and a top platform. All motion in space of the top platform is achieved by changing the length of the individual struts with sub-micron resolution.
In contrast to conventional multi-axis positioning systems, where single-axis positioners are stacked upon each other, parallel kinematics systems such as the Hexapod do not exhibit error-summation. Single stage inaccuracies, moving cables of the upper stages, cosine errors due to stack height of the single positioners are all eliminated, and a repeatability in space of a few microns can be achieved. Another big advantage is that with PI Hexapods the center of rotation (pivot point) stays where programmed during all motion.
Six Degrees of Freedom
No Moving Cables for Improved Reliability, Ease of Setup and Reduced Friction
Load Capacity 10 kg
Repeatability to 2 µm (Six-Axis Moves)
Significantly Smaller and Stiffer Package than Conventional Multi-Axis Positioners
Better Dynamics & Throughput
True Path Control
PivotAnywhere™ Virtualized Center of Rotation Set by Software