Linear Actuators for Hexapod Motion and Positioning
As the labor market continues to drive the need for increased automation, the demand for more complex motion solutions has followed suit. From improved task flexibility and miniaturization to higher load capacity and advanced controller technology, hexapod positioning systems are becoming more common in multiple industries. Though not new to the market, these versatile motion systems solve many industrial automation challenges, from semiconductor applications to automotive assembly lines.
What is a Hexapod?
Hexapods are six-legged, parallel kinematic positioning platforms utilized to solve complex robotic motion challenges. These versatile components allow the combination of numerous high-precision movements and processes that would otherwise prove difficult to realize. In addition, they facilitate precise positioning and load alignment via three linear and three rotational axes, equating to six axes of movement. In general, hexapods can be designed to accommodate load capacities ranging from 0.5 kg to more than 2000 kg, and provide movement in measurements as small as a few millimeters up to several hundred centimeters while maintaining submicron accuracy.
What Are the Primary Benefits of Hexapod Use in Motion Applications?
- The ability to handle heavy loads in any orientation
- Upside down mounting orientation capabilities
- All actuators are driven from the same platform, eliminating the accumulation of drive/guide errors that can occur in stacked systems
- Easy determination of motion limits and workspace based on the selected center of rotation
- No dragging cables (which cause torque and frictions issues)
- Compact size
- Overall stiffness and reduced inertia equate to quicker responses and higher dynamics, repeatability, and accuracy.
Applications Incorporating Hexapod Motion and Positioning Platforms
The possibilities for incorporating hexapod motion and positioning platforms are vast. Several common application examples include:
- 6D Alignment Systems
- Material Processing Applications
- Reflector and Mirror Positioning in Telescopes
- Inspection Systems
- Precision Patient Positioning in Radiation Machines
- Coordinate Measuring Machines
- Motion Scanners and Simulators
- Camera Image Stabilization Testbeds
The Use of Helix Linear Technologies Products in Hexapods
Many hexapods for custom applications are custom-built from a primary platform. The actuators used are certainly not a one size fits all condition. However, for most applications, the main challenge is the constraint of fitting the actuation system into the allotted space, not only in the confines of one axis but collectively in all six.
Another challenge is how to drive these axes. Applications can require different degrees of torque, thrust, resolution, and accuracy. The type of driver, controller and power supply will also impact the motor selection. Various motor options are available depending on the cost, space and performance needed. Stepper motors, brush or brushless, gear motors, and servo motors are all possibilities. Typically, a value-added assembly will be in the form of an electric cylinder or captive linear actuator.
To yield higher speeds, Helix Linear Technologies can provide tiny lead screw diameters with high lead ratios (up to four times the diameter). Small diameter metric ball screws are also available in applications that require higher efficiency and load requirements. These lead screws and ball screws can be supplied as components and connected to a motor, or we can provide the actuator with the motor attached. The lead screw or ball screw can be integrated directly into the motor or, if not feasible, joined by coupling the two together externally.
Specialty motors such as half stack stepper motors or other flat motors (often called pancake motors) can be supplied with the lead screw or ball screw assembly for applications with an overall length restriction where a specific desired stroke length is required. In addition, Helix Linear Technologies can supply motors with customized specifications allowing us to combine them with our lead screw and ball screw assemblies to provide a complete linear motion assembly for your hexapod applications.
Overall, this technology has multiple forms, including single axis, bi-pod axis, and multi-axis applications. All of which can incorporate the same motor and lead screw technology. We recommend consulting with our applications engineers to collaborate on your project. Our engineers will review your project requirements and work with you to deliver an optimized solution.
