Echinoderm-Inspired Tube Feet for Robust Robot Locomotion and Adhesion

Bell, Michael A.; Pestovski, Isabella; Scott, William L.; Kumar, Kitty; Jawed, Mohammad; Paley, Derek A.; Majidi, Carmel; Weaver, James C.; Wood, Robert J.

doi:10.1109/lra.2018.2810949

Cited by 29 publications

(13 citation statements)

References 18 publications

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“…Consisting of dozens of separate and potentially error-prone components, modern soft robotic prototypes can exhibit staggeringly complex networks of tubes, pumps, valves, and sensors that are required for their successful operation. [1][2][3][4][5][6][7][8][9] As a consequence of this multicomponent complexity, most soft robots are bulky and inefficient, are difficult and time-consuming to service and upgrade, exhibit limited modularity, and offer limited rapid prototyping options for quickly exploring novel gaits or multilegged configurations. [10][11][12][13][14][15] In contrast, soft robotic prototypes that focus on the integration of customized fluidic systems with their adjacent actuators can offer the potential for increased actuator performance, longer autonomous range, and a more compact form factor.…”

Section: Introductionmentioning

confidence: 99%

A Modular and Self‐Contained Fluidic Engine for Soft Actuators

Bell

Gorissen

Bertoldi

et al. 2021

Advanced Intelligent Systems

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Fluidic actuation in soft robots traditionally requires a complex assemblage of pumps, regulators, valves, and sensors, often resulting in large and bulky support systems. This added bulk can often hinder a robot's ability to be untethered, perform complex tasks, or bring challenges when it comes to maintenance or upgradeability. To address these limitations, herein, a simple and highly modular bidirectional soft robotic appendage is presented that integrates the pump, flow lines, and actuator into a compact, closed hydraulic system, which is driven by an integrated stepper motor, allowing for positional control and fast response times. The actuator can also be swapped in under five seconds, allowing for rapid reconfiguration. Each component has been thoroughly characterized to determine an overall electrical to mechanical efficiency of the system, and from these calculations, it is demonstrated that the actuator utilizes only 1/15th the required energy to achieve a specific bending angle, and is four‐fold more power‐efficient than similar‐sized soft actuators and pumping systems reported in the literature. The integrated actuator and fluidic engine construct presented here thus represents a major departure from previous soft actuator control platforms in that everything is simplified down to a single self‐contained unit, demonstrating unparalleled versatility and modularity.

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Section: Introductionmentioning

confidence: 99%

A Modular and Self‐Contained Fluidic Engine for Soft Actuators

Bell

Gorissen

Bertoldi

et al. 2021

Advanced Intelligent Systems

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“…Similarly, injection molding can help to saturate fabrics and meshes inside of a mold, whereas fabric and mesh must often be pre-dipped into silicone or massaged by hand before placement in the mold for casting. [12]…”

Section: Traditional Castingmentioning

confidence: 99%

“…An example of a mesh used to secure rigid inserts is demonstrated by Bell et al in the incorporation of magnets within an elastomeric matrix. [12] A similar strategy can be used to reinforce boundaries between successive layers of rubber that would otherwise be at risk of delamination. This was used by Becker et al [9] to create fluidic channels in large arrays of actuators, where cheese cloth was incorporated into an early stage of the molding process, and portions shielded from the first application of silicone were later used to mechanically anchor additional rubber.…”

Section: Fabrics and Mesh Insertsmentioning

confidence: 99%

“…[10] Small magnets or nuts can also be embedded, but require a mesh to grip enough silicone to prevent the magnet or nut from pulling out during use. [12,13] 3D printers and materials have recently become more capable of directly printing soft actuators, potentially eliminating the need for mold making and casting. [14,15] Thermoplastic polyurethane (TPU), which is widely and cheaply used in shoes and clothing, has the potential to be directly printed producing robust bellows.…”

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Injection Molding of Soft Robots

Bell

Becker

Wood

2021

Adv Materials Technologies

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tional components such as magnets or tubing, or using new production methods such as directly 3D printing soft actuators. [1] The creation of internal voids and undercuts is inherently a challenge when molding. The traditional method is to glue two parts together, [2] or dip a cured half in uncured material. [3] Soluble or wax cores can allow for complex voids which are later removed out drain holes. [4][5][6] Soft cores are flexible (usually softer than the desired molding material), and enable voids to be created while being able to be reused multiple times. [7] Using a technique from industry, rotational molding that is normally used to make large plastic products such as kayaks, can be used to create internal voids in soft actuators, but control of the wall thickness becomes difficult for features such as bellows. [8] Alternatively, dip-coating can control the internal geometry but control of the external wall thickness is difficult. [9] Strain limiting layers are the most common type of reinforcements embedded into soft actuators, such as paper or fabric sheets to prevent extension of an actuator. [10,11] In order for embedded components to adhere to the silicone, components can be dipped and stuck to a structure, [11] or molded during the casting process. [10] Small magnets or nuts can also be embedded, but require a mesh to grip enough silicone to prevent the magnet or nut from pulling out during use. [12,13] 3D printers and materials have recently become more capable of directly printing soft actuators, potentially eliminating the need for mold making and casting. [14,15] Thermoplastic polyurethane (TPU), which is widely and cheaply used in shoes and clothing, has the potential to be directly printed producing robust bellows. [16] Recently, Voxel8's ActiveLab Digital Fabrication System (Voxel8, Somerville, MA, USA) has been able to print varying stiffness TPU with large overhangs while curing on-the-fly. Another method, embedded 3D printing, allows complex microchannels to be produced using sacrificial materials to create void space after silicone is cured. [17] Injection Molding Soft RobotsWe have developed a low-cost injection molding method ($10s-$100s), as seen in Figure 1, that incorporates the high pressure and in-line mixing capabilities of industrial liquid silicone injection molding machines into a versatile machine for prototype and low volume production. Our setup allows for To date, injection molding has not been a practical manufacturing method for soft robots due to machine costs, large volumes of liquid silicones required, and the inability to change materials quickly between shots. Injection molds are typically machined from metals to allow for high pressure and clamping forces, which further limits the ability to rapidly prototype soft robots when molds could cost thousands of dollars. To circumvent these issues, a lowcost injection molding system and process are pioneered. In this article, the apparatus, design process, economics, and workflow are described using standard stereolithogra...

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“…One study implemented a crawling mechanism similar to the one seen in sea cucumbers in a robot [58]. Other studies have resulted in: (1) The design and manufacture of a magnetically-controlled crawling mechanism based on tube feet [59]; (2) the design and testing of an echinoderm tube feet inspired suction device with an improved performance in holding onto rough surfaces, together with a quick release mechanism [60]; and (3) the creation of a sea urchin inspired robot, capable of traversing irregular surfaces [61].…”

Section: Current Echinoderm-inspired Roboticsmentioning

confidence: 99%

Sea Urchins as an Inspiration for Robotic Designs

Stiefel

Barrett

2018

JMSE

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Neuromorphic engineering is the approach to intelligent machine design inspired by nature. Here, we outline possible robotic design principles derived from the neural and motor systems of sea urchins (Echinoida). Firstly, we review the neurobiology and locomotor systems of sea urchins, with a comparative emphasis on differences to animals with a more centralized nervous system. We discuss the functioning and enervation of the tube feet, pedicellariae, and spines, including the limited autonomy of these structures. We outline the design principles behind the sea urchin nervous system. We discuss the current approaches of adapting these principles to robotics, such as sucker-like structures inspired by tube feet and a robotic adaptation of the sea urchin jaw, as well as future directions and possible limitations to using these principles in robots.

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Echinoderm-Inspired Tube Feet for Robust Robot Locomotion and Adhesion

Cited by 29 publications

References 18 publications

A Modular and Self‐Contained Fluidic Engine for Soft Actuators

A Modular and Self‐Contained Fluidic Engine for Soft Actuators

Injection Molding of Soft Robots

Sea Urchins as an Inspiration for Robotic Designs

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