Soft Sleeve Actuator Force Analysis Reveals 112N at Zero Extension
New model predicts force drop from 112N to zero over 40mm extension at 125kPa
Soft sleeve actuators (SSAs) are gaining traction in wearable robotics by embedding pneumatic actuation directly into sleeve-like structures, eliminating external attachments while maintaining limb compliance. However, their force-generation behavior has been poorly understood. Mohammed Abboodi's new paper presents an analytical and experimental force analysis of a linear soft sleeve actuator (LSSA), developing a quasi-static model that captures net axial force as a combination of pressure contributions from the cap and folded walls minus axial stiffness effects. The model incorporates internal pressure, projected areas, fold geometry, displacement, and an experimentally fitted stiffness relation.
Prescribed-extension and static-load experiments reveal critical performance characteristics. At 125 kPa, output force drops from approximately 112 N at zero extension to nearly zero at 40 mm—a 100% reduction over a short stroke. Static loading further delays measurable force onset and reduces peak output, particularly at low and intermediate pressures. The work highlights that LSSA force is governed by coupled pressure-geometry-displacement-stiffness dynamics, providing actionable insights for designers of soft exoskeletons and assistive devices.
- At 125kPa, LSSA force drops from ~112N (zero extension) to near zero at 40mm
- Static external loading delays force onset and reduces output at low/intermediate pressures
- Model integrates pressure, geometry, displacement, axial stiffness, and loading effects
Why It Matters
Enables more predictable soft actuator design for exoskeletons and wearable assistive robots