The World’s First and Only 6 Degree-of-Freedom Nano-Positioner with +/- 30 Degrees Tip and Tilt Travel

At the recent Photonics West show, San Francisco, CA, USA,  ALIO Industries released the all new HH-30D Hybrid Hexapod® — the industry’s only 6-Degree-Of-Freedom (6-DOF) nano positioning device with +/-30 degrees tip and tilt travel. 

The Hybrid Hexapod® was developed by ALIO Industries to address the inherent performance limitations of conventional hexapods. ALIO’s Patented 6-Degree-Of-Freedom (6-DOF) design seamlessly blends and takes advantage of the strengths of serial and parallel kinematic structures while avoiding their weaknesses.

The Hybrid Hexapod® offers far greater functional versatility, nanometer-level accuracy, repeatability, and superior 6-DOF trajectories than is possible with any traditional hexapod or stacked stage configuration. The unique design is comprised of a parallel kinematic tripod to deliver Z plane and tip/tilt motion. This tripod is integrated with a monolithic serial kinematic stage for XY planar motion. A rotary stage integrated into the top of the tripod (or beneath depending on application needs) provides 360-degree continuous yaw (Theta-Z) rotation. In this hybrid design, individual axes can be customized to provide XY travel ranges from millimeters to virtually unlimited ranges while maintaining nanometer-levels of precision. Novel forward and inverse controller kinematics provide an unlimited number of programmable tool center point (TCP) locations.

The HH-30D’s +/- 30 degree tip/tilt travel is by far the most angular travel range available from any 6-DOF positioner on the market, and offers the same unmatched positioning performance found in any of ALIO’s full-line of Hybrid Hexapod® systems. Such a large travel range is unprecedented, and it must also be appreciated that this angular range is the full conical motion of the device and NOT just the available angles from the primary pitch (Theta-Y) and roll (Theta-X) axes. 

Furthermore — and as is the case on any Hybrid Hexapod® and completely the opposite of any legacy 6-legged Hexapod — this large angular range does not consume any notable XY travel when the TCP is set at the default 0,0,0 location (top center).  Compare this with any alternative traditional hexapod design, and users of the ALIO solution have at least double the amount of tip and tilt range while still having the full XY and Theta-Z travel available.  

The new HH-30D Tripod design leverages ALIO’s experience from the field proven Mini Hybrid Hexapod® by using precision ballscrews driven by frameless servo motors.  What makes this travel possible is an all-new upper joint design that provides the exceptional travel range in an innovative self-nesting package which keeps the profile extremely low and stiffness very high. Future iterations with this innovative joint can easily incorporate ALIO’s linear motor driven / pneumatically counter balanced links.   

The travel range of the tripod is 62mm, which for applications where only a few degrees of tip/tilt are needed would provide a significant amount of remaining pure vertical (Z) travel. Applications that would directly benefit from the large tip/tilt angle include freeform and aspheric optics metrology, taper angle control in laser micro processing, and additive manufacturing. ALIO has also recognized some precision assembly/packaging applications where large offset angles are needed to “reach” into or around complex spaces. 

The HH-30D Tripod can be supplied with virtually any ALIO XY stage to provide a wide range of XY travel options – again, something that is not possible with a standard hexapod.  While any XY stage can be used, the company has currently released models for three configurations including the 60mm XY Ballscrew Driven XY from the Mini Hybrid Hexapod®, the LM100XY Monolithic Stage, and the CM200XY Low Profile Monolithic Stage.  The two latter configurations come with an umbilical cable management system.

The HH-30D with 60mm XY, 62mm Z and unlimited Theta Z starts at $44,900 (€40,000) with controller, which means the unit is comparably priced with industry alternatives but with features and performance they cannot match. The larger (LM) Linear Motor Driven version that was exhibited at the Photonics West show starts at $50,950 (with controller).  With 100mm XY travel range andthe throughput available from linear motor drives this unit essentially has no meaningful competition. 

ALIO Industries has spent 2019 working with numerous customers from across industry that are exploiting the ability to innovate through the use of true nanometer-level motion control solutions.

2019 has been a pivotal year for established nanometer-level motion control solution provider ALIO Industries. Throughout the year, news and coverage of ALIO’s Hybrid Hexapod® has reached every corner of industry globally, and the momentum that has been gained has been exciting as ALIO has helped existing and new customers reach new levels of precision in motion control.

Bill Hennessey says, “In many ways, the ultra-precise end of the motion control market is quite a confusing place to be, as the handful of extremely precise motion control suppliers tend to use non-consistent and often illusory ways of describing the levels of precision that they can attain. ALIO has always worked in the area of nanometer-level motion control, and as such has a unique perspective on what really works when looking for this level of precision. Because of this, during 2019, and with the Hybrid Hexapod® very much front and center, we have focussed on educating the customer base to navigate alternative solutions, and give them the tools to interrogate solutions providers in such a way that they can secure a motion control technology suited to their specific applications.”

In the area of hexapods, this has required ALIO Industries to identify where the usefulness of conventional hexapods expires, as it is here that the Hybrid Hexapod® finds its unique niche.

Hexapods are motion control technologies that operate with 6 degrees of freedom (DOF), and the standard hexapods that abound on the market today satisfactorily service applications where micron motion tolerances are required, but as the demand for nanometer requirements expands, standard hexapods struggle somewhat.

This is because there are performance limitations inherent in all “conventional” hexapod designs.  They operate within 3-dimensional space, and have errors in all 6 DOF.  However, hexapod motion systems have typically only been characterized by performance data of a single degree of freedom.  This practice leaves error sources unaccounted for in several degrees of freedom, especially in the areas of flatness and straightness, which are critical precision needs at the nanometer-level.  The hexapod’s best flatness and straightness of travel is still no more precise than in the order of magnitude of tens of microns per axis. 

Because hexapods have six independently controlled links joined together moving a common platform, the motion error of the platform will be a function of the errors of ALL links and joints.  Hexapods are known to have optimum accuracy and repeatability when performing Z-axis moves, because all links perform the same motion at the same relative link angle.  However, when any other X, Y, pitch, yaw or roll motion is commanded, accuracy and geometric path performance of the hexapod degrades substantially because all links are performing different motions.  In the case of legacy hexapods built with non-precision joints and motion controllers that are not capable of forward and inverse kinematics equations, the source of error is even more pronounced.

Furthermore, it is generally accepted that hexapods have relatively good stiffness compared to serial stacked multi-axis systems.  However, it is often only the hexapod’s “Z” (vertical) stiffness that is considered.  Geometric design stiffness has a critical impact on and hexapod’s platform repeatability and rigidity.  A lack of design stiffness relates directly to a weak XY plane stiffness with the conventional hexapod working platform.  Moreover, this inherent design flaw of the conventional hexapod negatively affects XY axis performance, especially with thermal bonding or machining applications that require more force to be performed accurately within the XY plane.

The Hybrid Hexapod® was developed by ALIO to address the critical weaknesses of conventional legacy hexapod designs, as well as the weaknesses of stacked serial stages, and to achieve nanometer -level accuracy, repeatability, and high-integrity flatness and straightness during motion.  It utilizes a tripod parallel kinematics structure to deliver Z plane and tip/tilt motion, integrated with a monolithic serial kinematic structure for XY motion.  A rotary stage integrated into the top of the tripod (or underneath it depending on application needs) provides 360-degree continuous yaw rotation.  In this hybrid design, individual axes can be customized to provide travel ranges from millimeters to over one meter, while maintaining nanometer-levels of precision. 

Hennessey continues, “Engineers working at the cutting edge of what is possible must be stimulated to ask more as they see that this technology reaches places others cannot, has the potential to promote innovations, and can optimise efficiency and cost-effectiveness in manufacture. The Hybrid Hexapod® is orders of magnitude more precise than traditional hexapods, being 100 x stiffer, 30 x faster, and with 10x the usable work envelope of industry standard options.”

ALIO is always eager to discuss how the Hybrid Hexapod® can be used to benefit customer applications, and the company will work to customize specific solutions for particular customer applications.

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