6-Axis Hexapod Family Moves Half Ton Loads with Sub-Micron Precision

Designed for multi-axis micropositioning tasks in industrial automation, optics, semiconductor, aerospace, and simulation applications, the H-855 precision positioning platform combines high load capacity with six-axis precision motion in a compact parallel-kinematic design. Four standard configurations allow customers to select a system optimised for precision and load capacity, speed, compact dimensions, or extended travel.

Rather than using one mechanical configuration for every application, the H-855 family uses a modular architecture that allows the mechanics to be adapted to different performance requirements.

The H-855.H2A precision positioning platform is optimised for accurately moving heavy components and supports payloads up to 500 kg (1100lbs) when mounted with the base plate horizontal. Typical minimum incremental motion is 0.3 m in X and Y and 0.15 um in Z, with typical unidirectional repeatability of 0.4 um in X and Y and 0.15 um in Z.

The H-855.G2A0B variant focuses on higher-throughput applications, with velocities up to 10 mm/s and features an integrated holding brake.

The H-855.H2AC uses folded actuator legs and smaller platforms to reduce the required installation space.

Lastly, the H-855.H2AL is designed for applications requiring extended motion ranges.

Depending on configuration, translational travel extends to 320 mm in X and Y and 150 mm in Z, while rotational motion extends to 120 degrees around the Z axis.

Parallel kinematics for heavy loads

Unlike stacked serial positioning systems, a hexapod controls all six degrees of freedom using six coordinated actuators operating between a common base and moving platform.

The parallel structure distributes loads through the complete mechanism while providing high stiffness and a favourable load-capacity-to-size, and weight ratio. It also avoids the accumulation of errors associated with stacking individual motion axes. Another advantage is the lack of dragged cables, as is common with traditional multi-axis serial kinematic motion systems.

H-855 hexapods cannot only move heavy loads, they also hold the loads without power. The H-855.H2A variant is self-locking up to 500kg (1100lbs), without the need for brakes.

The H-855 hexapod actuators are based on brushless DC gear motors with absolute rotary encoders. Absolute position information is available immediately after power-up, eliminating the need for a referencing or homing move before operation. This can simplify startup and integration in automated equipment. A motor brake is optional.

Easy modifications possible

The modular architecture allows actuator configurations, gear ratios, travel ranges, and geometries to be adapted within the same platform. This gives PI design engineers the ability to balance parameters, such as velocity, installation space, travel, holding force, and payload for a particular application, and develop custom hexapod variants for application-specific requirements.

The H-855 high-load hexapod family is controlled by PI's C-887 series 3rd generation hexapod motion controller, which calculates the inverse kinematics required to translate Cartesian position commands into coordinated actuator motion. User-defined work and tool coordinate systems are supported, and the centre of rotation can be freely defined in space. Depending on the controller version, interfaces include TCP/IP, RS-232, analogue I/O, and EtherCAT.

The H-855 parallel robotic family expands PI's hexapod technology into applications requiring precise multi-axis positioning of significantly heavier payloads, while providing engineers with several mechanical configurations instead of forcing load capacity, speed, travel, and installation size into a single design.