Design and Control of Isoperimetric Robot from Tape Springs
Hancey Jackson, Fisk Lundgreen, Nathan Usevitch
AI summary
Problem
Previous isoperimetric robots relied on inflated fabric tubes that leak and suffer from temperature-dependent pressure changes, while also restricting each triangle to only two active rollers.
Approach
The authors designed a tape-spring-based isoperimetric robot with three independently actuated rollers per triangular module and developed an optimization algorithm to distribute motion across all rollers for minimum-time reconfiguration.
Key results
- Design and assembly of a tape-spring isoperimetric octahedron robot
- Kinematic model and time-optimal control algorithm for three-roller modules
- Experimental validation showing faster and smoother motion with three active rollers
- Structural testing confirming a single triangular unit supports 22.5 kg before failure
Why it matters
Provides a reliable, high-speed alternative to pneumatic shape-shifting robots for space deployment and reconfigurable positioning platforms.
Abstract
Isoperimetric robots can dramatically change shape to adapt to different tasks. They are built from triangle modules, each formed by a continuous structural member that passes through three roller units, one at each corner. The robot changes shape as the roller units drive along the structural member, changing the location of the joints. Previous designs used inflated fabric tubes as the structural member, but these systems are prone to leaking and changes in pressure due to temperature effects. We present an isoperimetric robot composed of tape-springs (curved spring steel tapes) as the primary structural member, and assemble an octahedron robot. We detail the design of the roller modules that can drive along the tape spring. We also show that with tape springs, all three roller units at the vertices of each triangle can drive along the tape spring. This increases the robot’s speed moving between configurations and enables new types of behaviors, such as motion of the beam without motion of the rollers. We also present an optimization procedure for the tape spring isoperimetric robot that minimizes the time required to reach a desired configuration, assuming each roller is limited to a maximum speed.