Soft Crawling Robots: Design, Actuation, and Locomotion

Chen, Shoue; Cao, Yunteng; Sarparast, Morteza; Yuan, Hongyan; Dong, Lixin; Tan, Xiaobo; Cao, Changyong

doi:10.1002/admt.201900837

Cited by 144 publications

(75 citation statements)

References 113 publications

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“…[50] In contrast to presetting asymmetric surface topographies on the substrate, it will be better to create robust soft robots that can generate anisotropic friction regardless of the surface they crawl on. [76,79] A possible method to adopt such strategies is to allow the robots to produce asymmetrical deformation along their bodies when they are executing the two-anchor crawling locomotion. [76,79,80] This can be realized by imparting different properties and features along the characteristic length of the soft robot.…”

Section: Crawlingmentioning

confidence: 99%

“…[76,79] A possible method to adopt such strategies is to allow the robots to produce asymmetrical deformation along their bodies when they are executing the two-anchor crawling locomotion. [76,79,80] This can be realized by imparting different properties and features along the characteristic length of the soft robot. [52,61,81] To facilitate untethered crawling via electrochemical actuation, Gupta et al adopt this twoanchor crawling strategy and incorporate three forms of asymmetry along the robot, which is made of a polypyrrole (PPy) conducting film (Figure 2C).…”

Section: Crawlingmentioning

confidence: 99%

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Locomotion of Miniature Soft Robots

Tan

et al. 2020

Advanced Materials

101

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as prospective aerial vehicles that can significantly enhance the efficiency of search-and-rescue missions, [16][17][18] perform dangerous operations in hazardous environments, [18] and function as miniature nodes in sensor networks. [18] Because miniature robots are expected to operate in various types of environments, it is essential for them to possess effective locomotive gaits to navigate well in such terrains. [19,20] This will be especially true if the robots have to negotiate across highly unstructured environments such as within the human body or at disaster sites. [5,10,21,22] Of the miniature robots, the soft robots are significantly more promising than their rigid counterparts in developing dexterous gaits because their degrees of freedom and adaptability are considerably higher. [23][24][25] By having the ability to generate a series of time-varying shapes, miniature soft robots have shown to be able to perform various types of locomotion, which allow them to negotiate across complicated obstacles in their environments. [19,26] In addition to using such locomotion for navigation purposes, these gaits could also be beneficial for studying the locomotion of various small organisms. [4,13] In this report, we review the locomotion producible by miniature soft robots. The scope of this report is therefore different from reviews and commentaries that focus on the actuation, [3] applications, [2,21] or design [27] of miniature soft robots. It is also significantly different from reviews that focus on the applications of miniature robots, [1,10,11] and others that review the general principles [24,[28][29][30][31][32][33][34][35] or locomotion [34,36,37] of macro-scale soft robots. To facilitate our discussion, here we categorize the locomotion of the miniature soft robots into terrestrial, aquatic, and aerial locomotion (Figure 1). Under each category, we will highlight their key advancements, as well as their open challenges and future outlook. Except for the aerial robots that are in the centimeter-scale, our discussions will focus on soft robots that are in the micro/millimeter length scales. It is noteworthy that the discussions in this report will be restricted to synthetic materials. For miniature bio-robots based on natural materials, interested readers may refer to other reviews on biomolecular, biohybrid actuation, or microorganism-driven systems. [38][39][40][41][42][43] The report is organized as follows: Section 2 provides a brief discussion about the general actuation principles of miniature soft robots. This is followed by Sections 3-5 in which we discuss the advancements of miniature soft robots in their Miniature soft robots are mobile devices, which are made of smart materials that can be actuated by external stimuli to realize their desired functionalities. Here, the key advancements and challenges of the locomotion producible by miniature soft robots in micro-to centimeter length scales are highlighted. It is highly desirable to endow these small machines with dexterous locomotive gaits a...

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Section: Crawlingmentioning

confidence: 99%

Section: Crawlingmentioning

confidence: 99%

Locomotion of Miniature Soft Robots

Tan

et al. 2020

Advanced Materials

101

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“…[2,3] Inspired by creatures in nature, scientists have begun to explore soft-robotic systems, whose joints and body are made with soft and pliable materials similar to biological tissues. [4][5][6] Due to the flexible joints and body, soft robots can easily handle objects and structures that are soft, delicate, and sophisticated in shape with no need for complex control algorithm. [7,8] In terms of safety and security, a soft body is less likely to hurt people during the human-machine interaction, and can absorb most impact energy through deformation to avoid damage to the robot itself.…”

Section: Introductionmentioning

confidence: 99%

Liquid Crystal Polymer‐Based Soft Robots

Xiao

Jiang

Zhao

2020

Advanced Intelligent Systems

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Soft robots outperform the conventional robots on enhanced safety for human-machine interaction, environmental adaptability, and continuous deformation. In this blooming area of fundamental and technological importance, liquid crystal polymer networks and liquid crystal elastomers (referred to as LCNs) have emerged as one of the most valuable candidates for soft robots due to their complex, large, and reversible shape change capabilities. To date, much research effort, mainly regarding chemical synthesis, fabrication technologies and soft robot design, has been dedicated to LCN robotic systems to endow them with versatile and complex actions controlled by various stimuli. Herein, starting with the principle that governs the stimuli-responsiveness of LCNs, recent progress made in LCN soft robots is summarized while focusing on different robotic motions, such as grapping, walking, swimming, and oscillation. Especially, novel LCNs with intelligent functions such as reprocessability, reconfigurability, self-regulating behavior and associative learning capability, are highlighted. This article aims to provide significant insights into the design and development of LCN-based soft robots.

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“…The compliant nature and large range of motion of soft robotic fluidic actuators engenders a wide application scope with significant research interest (Rus and Tolley, 2015 ; Laschi et al, 2016 ; Gorissen et al, 2017 ; Shintake et al, 2018 ; Chen et al, 2019 ; Gifari et al, 2019 ; Runciman et al, 2019 ). Actuator designs typically comprise one or more elastomeric materials with the optional addition of strain limiting material, with single and multi-chamber configurations being selected based on application requirements.…”

Section: Introductionmentioning

confidence: 99%

Parallel Helix Actuators for Soft Robotic Applications

et al. 2020

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Fabrication of soft pneumatic bending actuators typically involves multiple steps to accommodate the formation of complex internal geometry and the alignment and bonding between soft and inextensible materials. The complexity of these processes intensifies when applied to multi-chamber and small-scale (∼10 mm diameter) designs, resulting in poor repeatability. Designs regularly rely on combining multiple prefabricated single chamber actuators or are limited to simple (fixed cross-section) internal chamber geometry, which can result in excessive ballooning and reduced bending efficiency, compelling the addition of constraining materials. In this work, we address existing limitations by presenting a single material molding technique that uses parallel cores with helical features. We demonstrate that through specific orientation and alignment of these internal structures, small diameter actuators may be fabricated with complex internal geometry in a single material-without-additional design-critical steps. The helix design produces wall profiles that restrict radial expansion while allowing compact designs through chamber interlocking, and simplified demolding. We present and evaluate three-chambered designs with varied helical features, demonstrating appreciable bending angles (>180 •), three-dimensional workspace coverage, and three-times bodyweight carrying capability. Through application and validation of the constant curvature assumption, forward kinematic models are presented for the actuator and calibrated to account for chamber-specific bending characteristics, resulting in a mean model tip error of 4.1 mm. This simple and inexpensive fabrication technique has potential to be scaled in size and chamber numbers, allowing for application-specific designs for soft, high-mobility actuators especially for surgical, or locomotion applications.

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Soft Crawling Robots: Design, Actuation, and Locomotion

Cited by 144 publications

References 113 publications

Locomotion of Miniature Soft Robots

Locomotion of Miniature Soft Robots

Liquid Crystal Polymer‐Based Soft Robots

Parallel Helix Actuators for Soft Robotic Applications

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