AirForce: Personal Fabrication of Large-Scale, Load-Bearing Animatronics Structures from a Single Tube

Paper Title

AirForce: Personal Fabrication of Large-Scale, Load-Bearing Animatronics Structures from a Single Tube

Publication Info

• Topic area: Personal fabrication of large-scale, actuated truss structures using inflatable tubes.
• Keywords: AirForce, single-tube structures, pneumatic actuators, personal fabrication, animatronics, inflatable truss, load-bearing, soft robotics, Blender plugin, reusable materials.

Background and Problem

• Problem / challenge: Existing methods for fabricating large-scale truss structures either require complex multi-component assemblies or lack integrated actuation capabilities. Prior systems like AirTied simplify assembly but do not support actuation.
• Significance: Enabling single-user assembly of large-scale, load-bearing, and actuated structures can democratize access to animatronics, reduce material waste, and simplify transport and setup.
• Motivation and related work: Previous works on truss structures and soft robotics have demonstrated scalable designs and actuation but often rely on complex fabrication setups or non-reusable components. AirForce builds on these by introducing actuation into single-tube truss designs while maintaining simplicity and reusability.

Solution

• Proposed approach: AirForce, a fabrication system that enables users to create large-scale, load-bearing, animated structures from a single inflatable tube with integrated pneumatic actuators.
• Novelty:
  1. Integration of three types of pneumatic actuators (buckling, muscle, telescoping) into a single-tube truss structure.
  2. Near 100% material reuse by allowing structures to be unfolded and refolded into new designs.
  3. A Blender plugin for designing, simulating, and generating fabrication instructions for custom structures.
  4. Custom hardware components (blowers, inlets, and high-pressure tubes) tailored for efficient and safe actuation.
• Procedure and key techniques:
  1. Design structures in Blender using the AirForce plugin, which simulates actuation and optimizes tube routing.
  2. Generate and apply assembly instructions via labeled stickers.
  3. Assemble nodes and actuators manually using Velcro ties and custom blowers.
  4. Inflate and control the structure using a smartphone app or MIDI devices.
  5. Disassemble and reuse materials for new designs.

Results

• Concrete findings:
  • Buckling actuators: Peak force of 480N (1.5m length, 200mbar).
  • Telescoping actuators: Peak force of 1400N (200mbar) with a stroke of 30–40cm.
  • Muscle actuators: Peak force of 2330N (200mbar) with linear contraction.
  • Fabrication time: Estimated at ~2 minutes per edge and 10 minutes per blower.
  • Reusability: Near 100% material reuse achieved.
• Advantage over baselines:
  • Eliminates the need for 3D-printed nodes, reducing fabrication time by over 10x compared to systems like TrussFormer.
  • Supports actuation, unlike AirTied, while maintaining single-tube simplicity.
• Experiments / evaluation:
  • Technical evaluation of actuator performance under various loads and pressures.
  • User study: Participants assembled a complex subassembly (24 edges, 2 blowers) in an average of 24 minutes.
  • Applications: Fabricated a 16m-long, 8m-high animatronic T-Rex and a motion platform capable of lifting human weight.
• Limitations and future work:
  • Limitations: Noisy blowers (>60dB), nonlinear force profiles for actuators, reliance on user judgment for pressure control.
  • Future work: Investigate forces at nodes and explore mass-spring-damper systems for dynamic applications.

Summary

AirForce introduces a novel system for fabricating large-scale, load-bearing, and actuated structures from a single inflatable tube. By integrating three types of pneumatic actuators and leveraging a Blender-based design workflow, the system enables efficient single-user assembly, near-total material reuse, and human-safe actuation. Evaluations demonstrate its effectiveness in creating complex animatronics, such as a motion platform and a large T-Rex sculpture. Future work aims to refine structural dynamics and expand application domains in entertainment and haptics.