A Monolithic Hand with Asymmetric Origami Bending and Dual-chamber Actuators

2026-07-24

AI Summary

This work proposes a monolithic soft robotic gripper that integrates asymmetric origami bending (AOB) and a dual-chamber (ADC) design to overcome the common trade-off between performance and manufacturability in existing soft grippers. By leveraging geometric asymmetry, the gripper achieves coordinated finger–palm motion and multifunctionality while enabling single-material, one-piece fabrication. Fabricated via selective laser sintering of thermoplastic polyurethane, the design was optimized through finite element analysis and analytical modeling. The resulting gripper achieves maximum bending angles of 203° for the fingers and 40° for the palm, with corresponding output forces of 6.3 N and 16 N, demonstrating high efficacy in performing a variety of representative grasping tasks.

Abstract

The passive adaptability inherent in soft robotic hands affords them advantages in applications that require safe and compliant interaction. However, existing soft robotic hands often struggle to simultaneously achieve adequate output performance and easy manufacturing due to their complicated structures. In this paper, we introduce the asymmetric origami bending (AOB) pattern for generating bending motion and the asymmetric dual-chamber (ADC) design for obtaining multifunction capability. The AOB single (AOB-S) chamber and AOB dual-chamber (AOB-D) units are designed and constitute the finger and palm actuators of the proposed Origami-inspired SOft Robotic (OSOR) hand. The OSOR hand achieves bio-inspired fingers-palm motions and adequate output performance within a monolithic structure that significantly simplifies the manufacturing process. By defining the asymmetric ratio to characterize the geometric asymmetry of the unit, the analytical models of the AOB and ADC structures are proposed. The Finite Element Analysis tool for the design of AOB actuators is obtained by geometric analysis. The asymmetric origami design grants the integrated manufacturing of the OSOR hand through a Selective Laser Sintering printing process with a single thermoplastic polyurethane material. The model and simulations are validated by experimental results. Experiments show the finger and palm maximum bending motion range of 203° and 40°, respectively, with output forces of 6.3 N and 16 N. The OSOR hand is capable of pinching a piece of tissue, stably grasping water bottles with two fingers, palm-only grasping, and completing the power grasps in the taxonomy of manufacturing grasps. The compactness, performance, and easy manufacturing of the proposed hand benefit the development of the soft robotic hand with new possibilities.

Problem

• soft robotic hand
• output performance
• easy manufacturing
• complicated structures
• passive adaptability

Innovation

• asymmetric origami bending
• dual-chamber actuator
• monolithic soft robotic hand
• selective laser sintering
• bio-inspired grasping