H-840: 6-Axis Robotics Hexapod Stewart Platform

The Physik Instrumente H-840 hexapod 6-axis precision positioning system offers high-resolution motion in 6 degrees of freedom. PI hexapod 6-axis stages are founded upon the Stewart Platform parallel-kinematics principle, with six high-performance motorized actuators functioning parallel between two platforms. H-840 hexapod positioning systems are available in diverse variants and optimized for particular motion and positioning applications.

Features

• Position repeatability to ±0.1 µm
• Brushless motors and absolute position encoder options
• Load capacity to 40 kg
• CIPA certified for camera tests
• Travel ranges to ±50 mm / ±30°
• Functions in any orientation

PI Makes Hexapod Start-Up Easy. Video Credit: PI (Physik Instrumente) LP

Equipped with a precision gear box installed within all six actuators, the H-840.G hexapod models offer higher load capacity and higher resolution. Contrarily, the H-840.D models utilize brushless servo motors to drive the actuators directly, offer higher dynamics, and facilitate velocities to 60 mm/s. The H-840.G2IHP variant with the least incremental motion to 20 nm is provided for applications that need even more enhanced resolution.

High-Performance Parallel-Kinematic Micro Robot Design

Broadly known as parallel kinematic machines or 6-DOF parallel micro-robots, H-840 high-resolution hexapods are parallel-kinematic positioning systems. The parallel kinematics principle provides excellent versatility and a more compact and firmer design than traditional, multi-axis positioning systems (stacked stages or serial kinematics).

Why Use Hexapod Positioning Systems?

Hexapod 6-axis positioning and motion systems offer better multi-axis accuracy repeatability than traditional stacked multi-axis stages and provide higher motion profile flexibility in a more compact environment.

In a stacked 6-axis stage, the bottom stage must carry a load of all five axes above while all six actuators support the lightweight moving platform of a hexapod in parallel.

Thanks to the considerably reduced moved mass, hexapod positioning systems can offer higher dynamics with an identical performance throughout all motion axes. For PI H-840 hexapod positioners, cable management is not a concern, as all six actuators are linked to the stationary base platform.

Using just two cables to plug into the static hexapod base platform, one for position information feedback to the hexapod controller and one for power, cable connectivity, and management are highly simplified within the local applications. There are no moving cables like stacked multi-axis stages.

It is also simpler to control servo controller tuning, as all six hexapod actuators are similar and usually have an identical load. In most hexapod applications, users do not need to alter the hexapod controller's default factory servo parameter settings.

Why Use Absolute Encoders in a High Precision Hexapod Positioning System?

H-840 6-axis hexapods come with absolute measuring position encoders. Immediately after startup, absolute encoders provide the right position data to its motion controller, making referencing moves unwanted and maximizing efficacy and security in case of a connectivity loss or power outage.

Four Decades of Parallel-Kinematics Motion Systems Design Experience

PI started developing parallel-kinematic nanopositioning systems more than 40 years ago and was a pioneer in the early 1990s. It introduced the motorized, high-precision 6-axis hexapod motion and positioning devices for challenging astronomy and optic applications. PI is the top international supplier of accurate parallel kinematic motion systems for sub-micrometer to sub-nanometer ranges, multi-axis positioning, alignment, and motion applications.

Superior Mechanical Design

For increased low friction and stiffness, the H-840 mechanics use cardanic joints with Z-offset. It also offers high-resolution encoders and high-precision ball screws. With many years of innovation expertise, the design teams have refined and optimized the mechanical design.

6-Axis Motion Controller/Programming/Software

The highly integrated, C-887 6-axis hexapod controller of PI facilitates the simple and rapid functioning of the H-840 hexapod systems. The users do not have to deal with the specific hexapod kinematics as all coordinate transformations are internally executed. Similar to the traditional stacked multi-axis positioning systems, all positions can be effortlessly addressed using Cartesian coordinates.

With PI’s in-built software packages and the highly efficient C-887 hexapod controller, users can seamlessly program arbitrary pivot points, essential while creating alignment applications for optics, fibers, lenses, or large panels. The company’s C-887 hexapod motion controller backs user-programmable coordinate systems and provides interface options that comprise USB, Ethernet, EtherCat^®, and analog inputs.

Brushless Servo Motors (BLDC) for High Duty Cycles

The brushless DC servo motors (BLDC) drive the six hexapod actuators. Contrary to the traditional brushed servo motors, BLDC motors do not produce particles and offer higher torque across a prolonged lifespan.

Manual 6-Axis Control

With the use of the C-887.MC2 manual control unit, PI hexapods can be controlled manually across all six degrees of freedom. This serves as a great benefit and timesaver while setting up an application.

The hand-held controller plugs into the hexapod controller and offers six individual knobs, one for each axis (X, Y, Z, Pitch, Yaw, Roll), identical to traditional 6-axis stages. The existing position data is illustrated on an LCD.

PI Hexapod Simulation Software Tool/Collision Avoidance Software

The boundaries of the workspace and load capacity of a hexapod are simulated by the hexapod simulation software, enabling users to assess that a specific hexapod model can handle the needed forces, loads, and torques that occur in an application.

The simulation software tool considers the position and motion of the hexapod along with the pivot point and multiple reference coordinate systems. The C-887.VM1 software aids users in preventing motion profiles that would result in the hexapod or assemblies mounted on the hexapod colliding with objects nearby.

Smaller and Larger Hexapods, High-Speed Hexapods

The H-840 6-axis system, a mid-size hexapod, is dedicated to medium loads. With a broad range of standard hexapod models and several configuration options, PI provides the most extensive range of accurate positioning hexapods: palm-sized devices like the H-811 or large units with hundreds of kilograms of load capacity.

PI hexapods are employed in all applications, from machining and automated assembly of complex parts, micro-lens and fiber-alignment, and automotive to aerospace. A unique voice-coil actuator hexapod is offered for high-velocity, high-precision motion simulation. When millisecond responsiveness and nanometer and sub-nanometer accuracy are needed, PI provides piezo-based multi-axis nanopositioning systems, like the PIMars 6DOF stage family.

Hexapod Applications: What Are Hexapods Used For?

H-840 hexapod 6-axis positioning systems are used in a broad array of automation, industrial, and research applications, including:

• Micromanipulation
• Micromanufacturing
• Fiber alignment
• Satellite sensor testing
• Automated optical and mechanical alignment
• Optical metrology
• X-Ray diffraction
• Tool inspection
• Beamline sample positioning
• Life sciences

The direct-drive high-speed version of the H-840 comes with a CIPA certification for motion simulation, which is essential for camera quality tests and imaging sensors.

Specifications

Source: PI (Physik Instrumente) LP

Technical data specified at 22±3 °C.

The maximum travel ranges of the individual coordinates (X, Y, Z, θX, θY, θZ) are interdependent. The data for each axis shows its maximum travel range when all other axes are in the zero position of the nominal travel range and the default coordinate system is in use, or rather when the pivot point is set to 0,0,0.

Connecting cables are not included in the scope of delivery and must be ordered separately.

Ask about customized versions.