Leveraging Internal Viscous Flow to Extend the Capabilities of Beam-Shaped Soft Robotic Actuators

Matia, Yoav; Elimelech, Tsah; Gat, Amir D.

doi:10.1089/soro.2016.0048

Cited by 30 publications

(20 citation statements)

References 27 publications

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“…We now turn to investigate by experiments the results achieved from the theoretical parametric study of the lumped model in Section II. As previously introduced, our soft robot consists of a rectangular elastic beam with two embedded slender fluidic networks, which were studied extensively in our previous works [22], [23], [45]. The robot is fabricated by casting Dragon Skin TM silicone rubber over two serpentine cores 3D-printed from PVA, which is water-soluble.…”

Section: Methodsmentioning

confidence: 99%

Understanding Inchworm Crawling for Soft-Robotics

Gamus

Salem

Gat

et al. 2020

IEEE Robot. Autom. Lett.

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Crawling is a common locomotion mechanism in soft robots and nonskeletal animals. In this work we propose modeling soft-robotic legged locomotion by approximating it with an equivalent articulated robot with elastic joints. For concreteness we study the inchworm crawling of our soft robot with two bending actuators, via an articulated three-link model. The solution of statically indeterminate systems with stick-slip contact transitions requires for a novel hybrid-quasistatic analysis. Then, we utilize our analysis to investigate the influence of phase-shifted harmonic inputs on performance of crawling gaits, including sensitivity analysis to friction uncertainties and energetic cost of transport. We achieve optimal values of gait parameters. Finally, we fabricate and test a fluid-driven soft robot. The experiments display good agreement with the theoretical analysis, proving that our simple model correctly captures and explains the fundamental principles of inchworm crawling and can be applied to other softrobotic legged robots.

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Section: Methodsmentioning

confidence: 99%

Understanding Inchworm Crawling for Soft-Robotics

Gamus

Salem

Gat

et al. 2020

IEEE Robot. Autom. Lett.

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“…Air is not the only fluid whose viscous effects can be exploited to control a soft robot. Silicone oil and glycerol were each used in a paper by Matia et al (2017). Here, the dynamics of a slender beam actuator with asymmetrically distributed channels filled with viscous fluid were solved.…”

Section: Controlling Soft Robots Via Viscous Effectsmentioning

confidence: 99%

Hardware Methods for Onboard Control of Fluidically Actuated Soft Robots

McDonald

Ranzani

2021

Front. Robot. AI

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Soft robots provide significant advantages over their rigid counterparts. These compliant, dexterous devices can navigate delicate environments with ease without damage to themselves or their surroundings. With many degrees of freedom, a single soft robotic actuator can achieve configurations that would be very challenging to obtain when using a rigid linkage. Because of these qualities, soft robots are well suited for human interaction. While there are many types of soft robot actuation, the most common type is fluidic actuation, where a pressurized fluid is used to inflate the device, causing bending or some other deformation. This affords advantages with regards to size, ease of manufacturing, and power delivery, but can pose issues when it comes to controlling the robot. Any device capable of complex tasks such as navigation requires multiple actuators working together. Traditionally, these have each required their own mechanism outside of the robot to control the pressure within. Beyond the limitations on autonomy that such a benchtop controller induces, the tether of tubing connecting the robot to its controller can increase stiffness, reduce reaction speed, and hinder miniaturization. Recently, a variety of techniques have been used to integrate control hardware into soft fluidic robots. These methods are varied and draw from disciplines including microfluidics, digital logic, and material science. In this review paper, we discuss the state of the art of onboard control hardware for soft fluidic robots with an emphasis on novel valve designs, including an overview of the prevailing techniques, how they differ, and how they compare to each other. We also define metrics to guide our comparison and discussion. Since the uses for soft robots can be so varied, the control system for one robot may very likely be inappropriate for use in another. We therefore wish to give an appreciation for the breadth of options available to soft roboticists today.

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“…Possibilities include controlling the viscous dynamics within the working fluid of an actuator with asymmetrically distributed channels to generate different time‐dependent deformation modes via a single pressure source. [ 42 ] Similarly, in a previous study, [ 43 ] the authors controlled the actuation sequence of a robot using the dynamics of its working fluid. Control via flow properties has the potential benefit of reducing the number of inputs into the soft robot without introducing any additional stiffness.…”

Section: Figurementioning

confidence: 99%

Magnetorheological Fluid‐Based Flow Control for Soft Robots

McDonald

Rendos

Woodman

et al. 2020

Advanced Intelligent Systems

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Soft robots are uniquely suited to solving many of the most complex, sensitive problems facing the robotics community. [1] With distributed degrees of freedom (DoF) and compliant structures, they can operate with motions and in locations that are unavailable to their traditional rigid counterparts. [2,3] Even a simple, low-cost soft robot can have a high degree of dexterity, adaptability, and redundancy, allowing for safe interaction with a variety of environments and biological structures. [4-6] While a variety of actuation methods have been explored, such as shape-memory alloys, [7,8] dielectric elastomers, [9] ionic polymers, [10,11] and hydrogel-based actuators, [12-14] among others, fluid-powered soft robots remain the most widespread due to their capacity to deliver large forces, large strokes, ease of fabrication, low cost, and safety. [4,15] In these systems, a fluid (liquid or gas) is used to pressurize a soft structure in a controllable way. Often, soft robot motion is achieved by embedding inflatable chambers within the elastomeric device and by exploiting the geometry or the mechanical properties of the materials comprising the structure such that controllable deformation can be obtained upon pressurization. [16] Previous work has demonstrated complex multi-DoF platforms achievable via progress in the manufacturing of soft structures. [17-22] However, as scientists and engineers continue to develop innovative systems that push the boundaries of dexterity and miniaturization, existing soft robots' limitations become apparent by way of several unsolved challenges related to controlling such complexities. Primarily, current fluidic-powered soft robots require one individually controlled fluidic line for each DoF, leading to various fundamental issues, including 1) how to individually control a large number of lines, 2) the limitations on the robot scale induced by the physical dimensions and quantity of external fluidic connections for a given number of DoFs, 3) the inability of the fixed fluidic network within the soft robot to adapt to the robot's changing needs, and 4) the need for tubing tethered to external flow control elements that together limit the independence and motility of the robot. While the limitations to mobility that a tether of tubes introduces to a soft robot are evident, the tubing itself also introduces a number of complications to the robot's dynamics and overall design. Large lengths of tubing between the robot and its pressure source may allow it to operate more remotely but introduce a control delay due to resistance proportional to the tube's length. Such delays reduce the speed of the robot, whereas the losses similarly reduce efficiency. While stiffer tubing can mitigate such effects, it limits the intrinsic advantages of soft robots and alters the delicate

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Leveraging Internal Viscous Flow to Extend the Capabilities of Beam-Shaped Soft Robotic Actuators

Cited by 30 publications

References 27 publications

Understanding Inchworm Crawling for Soft-Robotics

Understanding Inchworm Crawling for Soft-Robotics

Hardware Methods for Onboard Control of Fluidically Actuated Soft Robots

Magnetorheological Fluid‐Based Flow Control for Soft Robots

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