A Proprioceptive Soft Robot Module Based on Supercoiled Polymer Artificial Muscle Strings

Abstract

In this paper, a multi-functional soft robot module that can be used to constitute a variety of soft robots is proposed. The body of the soft robot module made of rubber is in the shape of a long strip, with cylindrical chambers at both the top end and bottom end of the module for the function of actuators and sensors. The soft robot module is driven by supercoiled polymer artificial muscle (SCPAM) strings, which are made from conductive nylon sewing threads. Artificial muscle strings are embedded in the chambers of the module to control its deformation. In addition, SCPAM strings are also used for the robot module’s sensing based on the linear relationship between the string’s length and their resistance. The bending deformation of the robot is measured by the continuous change of the sensor’s resistance during the deformation of the module. Prototypes of an inchworm-like crawling robot and a soft robotic gripper are made, whose crawling ability and grasping ability are tested, respectively. We envision that the proposed proprioceptive soft robot module could potentially be used in other robotic applications, such as continuum robotic arm or underwater robot.

Recent Advances in Perceptive Intelligence for Soft Robotics

“…[91,92] Stretching self-sensing methods offer an opportunity to achieve these goals based on the principle that changes in electrical parameters (e.g., resistance, inductance, and capacitance) caused by the EP and contraction of the material used to manufacture the actuator are highly correlated with the length of the actuator. [66,79,93,94] For example, Yang et al [95] developed a graphene oxide (GO)-enabled templating synthesis to produce reconfigurable, compliant, multifunctional metallic backbones for fabricating origami robots with built-in strain sensing (Figure 4d). Compared with traditional paper and plastic materials, the reconfigurable Pt backbones were more deformable and the conductive Pt-elastomer backbones (Pt robots) demonstrated distinct capabilities─such as stretching sensing─without the need for external electronics.…”

Sensorless Proprioception in Multi-DoF Dielectric Elastomer Soft Robots via System-Level Self-Sensing

“…These mechanisms allow for soft and compact designs, but lack intrinsic selfsensing features and have to rely on external hardware such as cable-driving motors or air compressors. Some of those shortcomings were addressed in [15], where the authors utilized the actuation fluid as an integrated resistive sensor, or in [16], where currently unused actuators can serve as sensors. Those approaches rely either on additional wiring or on alternating between actuation and sensing functions, thus, leaving room for technologies offering even tighter integration.…”

Design and Application of a Twisted and Coiled Polymer Driven Artificial Musculoskeletal Actuation Module

“…Inspired by such natural muscles, researchers have developed various soft actuators to replicate the functions of natural muscles (such as strain output, force generation, and power density). Compared with conventional actuators (such as DC motors), these soft actuators tend to be more flexible, conformable, and safer when interacting with humans [2].…”

“…It lead to a long heat-dissipation time after TCP heating. A similar soft robot module was presented by Yang et al, but in their design, TCP actuators were embedded in an open chamber made of rubber to improve the cooling speed [2]. The recovery force was offered by another parallelly placed TCP actuator during the cooling stage.…”