PA-13 Actuators in Tunnel Boring Machine for Urban Transportation

PA-13 Actuators in Tunnel Boring Machine for Urban Transportation

Nathan Bong
Nathan Bong
PA Engineer

As cities grow denser and traffic congestion intensifies, engineers are seeking smarter, more sustainable alternatives to road expansion. One promising solution lies underground: tunneling. At the University of Colorado Boulder, the CU Hyperloop team is reimagining tunneling technology through their student-led tunnel boring machine (TBM). By integrating PA-13 actuators for their 6-axis actuator system, the team has developed an innovative solution that replaces hydraulics with electric motion control — paving the way for safer, more sustainable urban infrastructure.


The Story Behind the Project’s Inspiration

At the core of CU Hyperloop’s TBM is a Stewart platform actuator system powered by PA-13 high force linear actuators. This 6-axis actuator system provides the precision required to steer, adjust, and propel the machine underground. Unlike traditional hydraulic systems, which can be bulky and complex, these actuators deliver compact and reliable motion control for heavy machinery while maintaining accurate and precise motion. The actuator precision engineering behind this setup allows the TBM to navigate underground obstacles while maintaining stability, making it one of the most advanced student-built tunneling machines in the 2025 Not-A-Boring Competition.

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Actuator Power Behind Electric Tunnel Boring Machines

The CU Hyperloop TBM relies on PA-13 actuators customized with hall effect sensors for two critical functions: propulsion and tunnel support. The tunnel boring actuator system, driven by PA-13 Industrial Linear Actuators, generates the enormous force needed to push the machine forward through soil and rock. Meanwhile, additional actuators manage the tunnel lining process, ejecting 3D-printed supports into place to maintain structural integrity.
  • Precision Control – Integrated hall-effect sensors provided positional feedback, enabling the team to track positioning and force via current feedback to program force limits in their PCB software. During one test, the team was astonished to see the actuator stop at precisely the desired force threshold underground.
  • Industrial Design – A high dynamic force rating of 3000 lbs per actuator combined with an IP66 ingress protection to handle dust, debris, and water ensured the PA-13 actuators with industrial reliability and long service life.
  • Safety & Efficiency – This electric tunnel boring technology eliminates the need for heavy hydraulic pumps and pressurized fluid lines, reducing complexity and improving safety. The result is an actuator-driven tunnel boring system that is lighter, more efficient, and easier to maintain as a major step forward in linear motion in tunneling technology.
  • Flexible Motion – The compact footprint of the actuators enabled a hexapod design that gave the TBM six degrees of freedom, allowing navigation underground — a capability that other competing teams lacked.

Our PA-13 offers industrial capabilities with customization options for hall effect sensor feedback!

Revolutionizing Urban Transportation with Automation


The implications of this project extend beyond competition. By adopting actuator-based tunneling systems, CU Hyperloop demonstrates how electric actuators can transform sustainable urban transportation. With smart city transportation technology, tunnels could reduce surface congestion, providing scalable underground infrastructure that supports eco-friendly growth. Electric linear actuators enable automation-driven tunneling, reducing costs while also supporting greener urban development compared to hydraulic alternatives. This approach could one day serve as a solution to reduce traffic congestion across growing metropolitan areas.


Engineering Growth Through Progressive Automations Partnership

From debugging electrical noise issues to designing force-limiting software, the TBM became a practical learning platform for future engineers to expand their technical skill sets. New members gained hands-on experience with hall-effect sensors, feedback loops, and current-to-force calibration. Over several years, the team had also refined the custom control boards they carried over for actuator management, shrinking them from bulky, heat-intensive designs into compact and efficient units. 

While the actuators themselves were central to the project’s success, CU Hyperloop also emphasized the value of Progressive Automations’ support. The team had faced tight deadlines before the competition, and Progressive Automations was able to deliver products in a quick and timely manner. More broadly, the partnership enabled the team to tackle a project that would otherwise be financially and technically out of reach through project sponsorships and our dedicated customer support team.

We offer a wide range of electric linear actuators for any application – click to browse! 

Looking Ahead: Next Year’s Machine

For the upcoming competition, CU Hyperloop is preparing a new 24-volt system architecture, which will require different actuator specifications. However, the team is eager to continue integrating Progressive Automations’ products in both propulsion and tunnel support.

With each iteration, the TBM becomes more reliable, and the students gain deeper expertise. The team’s ambition remains clear: to keep innovating in tunneling technology while inspiring other student teams to adopt electric actuators as a safer, simpler alternative to hydraulics.

FAQ Block

What role do PA-13 actuators play in tunnel boring machines?
- They drive the propulsion force and power the tunnel support system, enabling both forward motion and pivoting motion when changing directions.

How does a Stewart platform improve tunneling precision?
- It allows 6-axis motion control, giving the tunnel boring machines the ability to navigate underground obstacles with greater accuracy.

Can linear actuators handle the high-force requirements of tunneling?
- Yes, models like the PA-13 actuators deliver up to 3000 lbs of dynamic force, meeting the heavy-duty demands of tunnel boring.

Why choose electric actuators over hydraulic systems in tunneling?
- Electric linear actuators are safer, have a more compact overall system, are easier to maintain, and eliminate the complexity of hydraulic fluid lines.

How does this technology reduce urban traffic congestion?
- By enabling scalable underground tunnels, actuator-driven TBMs expand transportation networks beyond the limitations of surface roads.

What are the sustainability benefits of electric tunnel boring?
- They reduce oil usage, environmental risks, and can be integrated with renewable energy sources for greener infrastructure.

Are PA-13 actuators suitable for other heavy-duty industrial applications?
- Yes, their high force capacity and durable industrial designs make them ideal for various industries such as manufacturingrenewable energyagriculture, and industrial automation.

How reliable are actuators in continuous, high-load operations?
- The models that are reliable will offer suitable ratings to handle the specification requirements of each application. Our PA-13 actuators in this case are designed for long-term reliability, with sealed housings and robust construction with IP66 ingress protection for harsh environments, and can handle a 20% duty cycle for time driving motion.

What makes actuator-driven Stewart platforms ideal for tunneling projects?
- They combine compact design with precision motion control, allowing for versatile and efficient tunneling systems.

How does automation improve efficiency in urban infrastructure projects?
- Automation helps reduce manual intervention, lowers costs, and accelerates project timelines while maintaining safety.

In Summary

The CU Hyperloop project demonstrates how Progressive Automations’ PA-13 actuators can enable groundbreaking engineering initiatives. By offering high force capabilities in a compact, electrically driven package, the actuators allowed students to design innovative solutions and become a finalist in the Not-A-Boring Competition 2025.

We hope you found this project as interesting as we did, especially if you were looking for new ideas for your own innovations. If you have any queries about our electric linear actuators or wish to discuss our other products further, please do not hesitate to reach out to us! We are experts in what we do and will be happy to assist in any way we can.

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