An untethered isoperimetric soft robot

2020 ◽  
Vol 5 (40) ◽  
pp. eaaz0492
Author(s):  
Nathan S. Usevitch ◽  
Zachary M. Hammond ◽  
Mac Schwager ◽  
Allison M. Okamura ◽  
Elliot W. Hawkes ◽  
...  
Keyword(s):  
Shape Change ◽  
External Source ◽  
Edge Length ◽  
Complex Structures ◽  
Soft Robot ◽  
Soft Robots ◽  
Form Complex ◽  
Human Scale ◽  
Real World Applications ◽  
Rolling Locomotion

For robots to be useful for real-world applications, they must be safe around humans, be adaptable to their environment, and operate in an untethered manner. Soft robots could potentially meet these requirements; however, existing soft robotic architectures are limited by their ability to scale to human sizes and operate at these scales without a tether to transmit power or pressurized air from an external source. Here, we report an untethered, inflated robotic truss, composed of thin-walled inflatable tubes, capable of shape change by continuously relocating its joints, while its total edge length remains constant. Specifically, a set of identical roller modules each pinch the tube to create an effective joint that separates two edges, and modules can be connected to form complex structures. Driving a roller module along a tube changes the overall shape, lengthening one edge and shortening another, while the total edge length and hence fluid volume remain constant. This isoperimetric behavior allows the robot to operate without compressing air or requiring a tether. Our concept brings together advantages from three distinct types of robots—soft, collective, and truss-based—while overcoming certain limitations of each. Our robots are robust and safe, like soft robots, but not limited by a tether; are modular, like collective robots, but not limited by complex subunits; and are shape-changing, like truss robots, but not limited by rigid linear actuators. We demonstrate two-dimensional (2D) robots capable of shape change and a human-scale 3D robot capable of punctuated rolling locomotion and manipulation, all constructed with the same modular rollers and operating without a tether.

scholarly journals EuMoBot: replicating euglenoid movement in a soft robot

2018 ◽  
Vol 15 (148) ◽  
pp. 20180301 ◽  
Author(s):  
Krishna Manaswi Digumarti ◽  
Andrew T. Conn ◽  
Jonathan Rossiter
Keyword(s):  
Shape Change ◽  
Large Body ◽  
Small Mass ◽  
The Body ◽  
Soft Robot ◽  
Soft Robots ◽  
Characteristic Type ◽  
Viscous Forces ◽  
Wide Range ◽  
Euglenoid Movement

Swimming is employed as a form of locomotion by many organisms in nature across a wide range of scales. Varied strategies of shape change are employed to achieve fluidic propulsion at different scales due to changes in hydrodynamics. In the case of microorganisms, the small mass, low Reynolds number and dominance of viscous forces in the medium, requires a change in shape that is non-invariant under time reversal to achieve movement. The Euglena family of unicellular flagellates evolved a characteristic type of locomotion called euglenoid movement to overcome this challenge, wherein the body undergoes a giant change in shape. It is believed that these large deformations enable the organism to move through viscous fluids and tiny spaces. The ability to drastically change the shape of the body is particularly attractive in robots designed to move through constrained spaces and cluttered environments such as through the human body for invasive medical procedures or through collapsed rubble in search of survivors. Inspired by the euglenoids, we present the design of EuMoBot, a multi-segment soft robot that replicates large body deformations to achieve locomotion. Two robots have been fabricated at different sizes operating with a constant internal volume, which exploit hyperelasticity of fluid-filled elastomeric chambers to replicate the motion of euglenoids. The smaller robot moves at a speed of body lengths per cycle (20 mm min −1 or 2.2 cycles min −1 ) while the larger one attains a speed of body lengths per cycle (4.5 mm min −1 or 0.4 cycles min −1 ). We show the potential for biomimetic soft robots employing shape change to both replicate biological motion and act as a tool for studying it. In addition, we present a quantitative method based on elliptic Fourier descriptors to characterize and compare the shape of the robot with that of its biological counterpart. Our results show a similarity in shape of 85% and indicate that this method can be applied to understand the evolution of shape in other nonlinear, dynamic soft robots where a model for the shape does not exist.

scholarly journals Light-steered locomotion of muscle-like hydrogel by self-coordinated shape change and friction modulation

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Qing Li Zhu ◽  
Cong Du ◽  
Yahao Dai ◽  
Matthias Daab ◽  
Marian Matejdes ◽  
...  
Keyword(s):  
Gold Nanoparticle ◽  
Shape Change ◽  
Light Irradiation ◽  
Soft Robot ◽  
Nanocomposite Hydrogel ◽  
Soft Robots ◽  
Hydrophobic Substrate ◽  
Anisotropic Structures ◽  
Light Stimuli

Abstract Many creatures have the ability to traverse challenging environments by using their active muscles with anisotropic structures as the motors in a highly coordinated fashion. However, most artificial robots require multiple independently activated actuators to achieve similar purposes. Here we report a hydrogel-based, biomimetic soft robot capable of multimodal locomotion fueled and steered by light irradiation. A muscle-like poly(N-isopropylacrylamide) nanocomposite hydrogel is prepared by electrical orientation of nanosheets and subsequent gelation. Patterned anisotropic hydrogels are fabricated by multi-step electrical orientation and photolithographic polymerization, affording programmed deformations. Under light irradiation, the gold-nanoparticle-incorporated hydrogels undergo concurrent fast isochoric deformation and rapid increase in friction against a hydrophobic substrate. Versatile motion gaits including crawling, walking, and turning with controllable directions are realized in the soft robots by dynamic synergy of localized shape-changing and friction manipulation under spatiotemporal light stimuli. The principle and strategy should merit designing of continuum soft robots with biomimetic mechanisms.

scholarly journals Self-excited air flow passage changing device for periodic pressurization of soft robot

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Toshio Takayama ◽  
Yusuke Sumi
Keyword(s):  
Mobile Robot ◽  
Rotational Motion ◽  
Air Pressure ◽  
Soft Robot ◽  
Pressure Source ◽  
Large Delay ◽  
Soft Robots ◽  
Flow Passage ◽  
Output Pressure ◽  
Air Chamber

AbstractRecently pneumatic-driven soft robots have been widely developed. Usually, the operating principle of this robot is the inflation and deflation of elastic inflatable chambers by air pressure. Some soft robots need rapid and periodic inflation and deflation of their air chambers to generate continuous motion such as progress motion or rotational motion. However, if the soft robot needs to operate far from the air pressure source, long air tubes are required to supply air pressure to its air chambers. As a result, there is a large delay in supplying air pressure to the air chamber, and the motion of the robot slows down. In this paper, we propose a compact device that changes its airflow passages by self-excited motion generated by a supply of continuous airflow. The diameter and the length of the device are 20 and 50 mm, respectively, and can be driven in a small pipe. Our proposed in-pipe mobile robot is connected to the device and can move in a small pipe by dragging the device into it. To apply the device widely to other soft robots, we also discuss a method of adjusting the output pressure and motion frequency.

scholarly journals Additive Manufacturing for Soft Robotics: Design and Fabrication of Airtight, Monolithic Bending PneuNets with Embedded Air Connectors

Micromachines ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 485 ◽  
Author(s):  
Gianni Stano ◽  
Luca Arleo ◽  
Gianluca Percoco
Keyword(s):  
Additive Manufacturing ◽  
Wall Thickness ◽  
Chamber Wall ◽  
Soft Robotics ◽  
Soft Robot ◽  
Soft Robots ◽  
Bending Performance ◽  
3D Print ◽  
Air Tightness ◽  
The Relationship

Air tightness is a challenging task for 3D-printed components, especially for fused filament fabrication (FFF), due to inherent issues, related to the layer-by-layer fabrication method. On the other hand, the capability of 3D print airtight cavities with complex shapes is very attractive for several emerging research fields, such as soft robotics. The present paper proposes a repeatable methodology to 3D print airtight soft actuators with embedded air connectors. The FFF process has been optimized to manufacture monolithic bending PneuNets (MBPs), an emerging class of soft robots. FFF has several advantages in soft robot fabrication: (i) it is a fully automated process which does not require manual tasks as for molding, (ii) it is one of the most ubiquitous and inexpensive (FFF 3D printers costs < $200) 3D-printing technologies, and (iii) more materials can be used in the same printing cycle which allows embedding of several elements in the soft robot body. Using commercial soft filaments and a dual-extruder 3D printer, at first, a novel air connector which can be easily embedded in each soft robot, made via FFF technology with a single printing cycle, has been fabricated and tested. This new embedded air connector (EAC) prevents air leaks at the interface between pneumatic pipe and soft robot and replaces the commercial air connections, often origin of leakages in soft robots. A subsequent experimental study using four different shapes of MBPs, each equipped with EAC, showed the way in which different design configurations can affect bending performance. By focusing on the best performing shape, among the tested ones, the authors studied the relationship between bending performance and air tightness, proving how the Design for Additive Manufacturing approach is essential for advanced applications involving FFF. In particular, the relationship between chamber wall thickness and printing parameters has been analyzed, the thickness of the walls has been studied from 1.6 to 1 mm while maintaining air tightness and improving the bending angle by 76.7% under a pressure of 4 bar. It emerged that the main printing parameter affecting chamber wall air tightness is the line width that, in conjunction with the wall thickness, can ensure air tightness of the soft actuator body.

scholarly journals A soft robot that adapts to environments through shape change

2020 ◽  
Author(s):  
Dylan S. Shah ◽  
Joshua P. Powers ◽  
Liana G. Tilton ◽  
Sam Kriegman ◽  
Josh Bongard ◽  
...  
Keyword(s):  
Shape Change ◽  
Soft Robot

scholarly journals Euglenoid-Inspired Giant Shape Change for Highly Deformable Soft Robots

2017 ◽  
Vol 2 (4) ◽  
pp. 2302-2307 ◽  
Author(s):  
Krishna Manaswi Digumarti ◽  
Andrew T. Conn ◽  
Jonathan Rossiter
Keyword(s):  
Shape Change ◽  
Soft Robots

scholarly journals Lattice-based Monte Carlo simulation of the effects of nutrient concentration and magnetic field exposure on yeast colony growth and morphology

2021 ◽  
pp. 1-17
Author(s):  
Rebekah Hall ◽  
Daniel A. Charlebois
Keyword(s):  
Magnetic Field ◽  
Monte Carlo ◽  
Fungal Pathogens ◽  
Colony Growth ◽  
Yeast Cells ◽  
Complex Structures ◽  
Dependent Manner ◽  
Field Exposure ◽  
Form Complex ◽  
Physico Chemical

Yeasts exist in communities that expand over space and time to form complex structures and patterns. We developed a lattice-based framework to perform spatial-temporal Monte Carlo simulations of budding yeast colonies exposed to different nutrient and magnetic field conditions. The budding patterns of haploid and diploid yeast cells were incorporated into the framework, as well as the filamentous growth that occurs in yeast colonies under nutrient limiting conditions. Simulation of the framework predicted that magnetic fields decrease colony growth rate, solidity, and roundness. Magnetic field simulations further predicted that colony elongation and boundary fluctuations increase in a nutrient- and ploidy-dependent manner. These in-silico predictions are an important step towards understanding the effects of the physico-chemical environment on microbial colonies and for informing bioelectromagnetic experiments on yeast colony biofilms and fungal pathogens.

Adaptive Control of Large-Scale Soft Robot Manipulators With Unknown Payloads

2019 ◽  
Author(s):  
Jonathan S. Terry ◽  
Justin Whitaker ◽  
Randal W. Beard ◽  
Marc D. Killpack
Keyword(s):  
Adaptive Control ◽  
Large Scale ◽  
Robot Manipulator ◽  
Coupling Model ◽  
Effective Control ◽  
Soft Robot ◽  
Soft Robots ◽  
Pneumatic Actuators ◽  
Integral Controller ◽  
Model Reference Adaptive

Abstract The compliance and other nonlinear dynamics of large-scale soft robots makes effective control difficult. This is especially true when working with unknown payloads or when the system dynamics change over time which is likely to happen for soft robots. In this paper, we present a novel method of coupling model reference adaptive control (MRAC) with model predictive control (MPC) for platforms with antagonistic pneumatic actuators. We demonstrate its utility on a fully inflatable, six degree-of-freedom pneumatically actuated soft robot manipulator that is over two meters long. Specifically, we compare control performance with no integral controller, with an integral controller, and with MRAC when running a nominal model predictive controller with significant weight attached to the end effector.

Omnidirectional Soft Robot Platform with Flexible Actuators for Medical Assistive Device

2016 ◽  
Vol 10 (4) ◽  
pp. 494-502 ◽  
Author(s):  
Mohamed Najib Ribuan ◽  
◽  
Shuichi Wakimoto ◽  
Koichi Suzumori ◽  
Takefumi Kanda ◽  
...  
Keyword(s):  
Assistive Devices ◽  
Assistive Device ◽  
Maximum Speed ◽  
Soft Robot ◽  
Control Parameters ◽  
Soft Robots ◽  
X Ray ◽  
Maximum Payload ◽  
Forward Locomotion ◽  
Robot Platform

This manuscript explains the employment of flexible actuators to act as a soft robot and transporting agent to assist medical X-ray examinations. Although soft robots from silicone material can be transparence and a human compliance used as medical assistive devices, soft robots have some problems: they tend to be sluggish, have long and imprecise gait trajectories, and need their control parameters to be adjusted for motion diversion. A soft robot with omnidirectional locomotion has been created, one that has a combination of pneumatic rubber legs that form a soft robot platform and an associated hardware setup. Tests have confirmed its omnidirectional locomotion ability; it has a maximum speed of 6.90 mm/s in forward locomotion and a maximum payload of 70 g. These features indicate that the robot can be used as a medical assistive device for fluoroscopy examinations.

Sign in / Sign up

Export Citation Format

Share Document