Temperature Driven Multi-modal/Single-actuated Soft Finger

TL;DR

This paper introduces a temperature-controlled multi-modal soft robotic finger capable of switching between bending, twisting, and extension modes, enhancing versatility and grasping capabilities in soft robotics.

Contribution

It presents a novel temperature-driven design enabling a single soft finger to switch motion modes and develops an analytical model for twisting motion, validated experimentally.

Findings

Achieved approximately 1mm repeatability in motion

Demonstrated 50% larger range of motion than standard actuators

Successfully grasped objects of various sizes, shapes, and stiffnesses

Abstract

Soft pneumatic fingers are of great research interest. However, their significant potential is limited as most of them can generate only one motion, mostly bending. The conventional design of soft fingers does not allow them to switch to another motion mode. In this paper, we developed a novel multi-modal and single-actuated soft finger where its motion mode is switched by changing the finger's temperature. Our soft finger is capable of switching between three distinctive motion modes: bending, twisting, and extension-in approximately five seconds. We carried out a detailed experimental study of the soft finger and evaluated its repeatability and range of motion. It exhibited repeatability of around one millimeter and a fifty percent larger range of motion than a standard bending actuator. We developed an analytical model for a fiber-reinforced soft actuator for twisting motion. This helped us relate the input pressure to the output twist radius of the twisting motion. This model was validated by experimental verification. Further, a soft robotic gripper with multiple grasp modes was developed using three actuators. This gripper can adapt to and grasp objects of a large range of size, shape, and stiffness. We showcased its grasping capabilities by successfully grasping a small berry, a large roll, and a delicate tofu cube.