Sensory-Motor Tissues for Soft Robots

Overview

The goal of this project is to generate novel actuators, sensors and materials to enable the creation of future soft robots. These technologies must be able to function under the demanding requirements imposed by highly deformable systems. This includes being able to generate, sense and/or withstand large deformations and forces without breaking. Some of our innovative solutions are discussed below.

Dielectric Elastomer Actuators

We are exploring the creation of new types of soft actuators based on Dielectric Elastomer Actuators (DEAs). DEAs are a type of artificial muscle actuator that exploits electrostatic forces by combining a soft flexible dielectric with stretchable electrodes.

 

Variable Stiffness Actuator

Controllable stiffness can be an important function for soft robots to exert large forces to environments, and to withstand external loads while keeping their shape. We developed a variable stiffness actuator using DEA and low-melting-point-alloy (LMPA) embedded silicone substrate. The actuator which we call variable stiffness dielectric elastomer actuator (VSDEA) exhibits a bending actuation and a high rigidity change (~90x) between the soft state and the rigid state.

 

 

Variable stiffness dielectric elastomer actuator (VSDEA)

 

To demonstrate the usefulness of the actuator, we developed a gripper consisted of two VSDEAs acting as fingers. The gripper showed successful handling of an object where the soft state leads to a better confirmation of the fingers, and the rigid state provides sufficient holding force.
 

 

The result will be presented at the 2015 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), Hamburg, Germany.

This work has been done as a collaboration work with the EPFL-LMTS.

 

Foldable Antagonistic Actuator

We developed an actuator based on DEA that is capable of antagonistic actuation and passive folding. The actuator enables foldability in robots, and gives robustness to external shocks and overload by its compliance.

Concept of the actuator

 

 

We also developed a micro air vehicle (MAV), in which the actuator was used as an elevon to demonstrate its usefulness. The MAV performed fully controlled flights by only the actuators via a remote transmitter with a human pilot.

(left) The elevon actuator, and (right) the folded state of the actuator

 

This work has been done as a collaboration work with the EPFL-LMTS, and related information can be found on their website.

 

Soft Grippers based on DEMES

Dielectric Elastomer Minimum Energy Structures (DEMES) are a special type of DEA based on the balance between mechanical and electrical energy. A DEMES device can be fabricated by bonding a stretched DEA to a flexible frame. This composite structure folds up into a minimum energy configuration shown below. When a voltage is applied to the DEA, it expands, returning whole device to the flattened state.

We developed and characterized a prototype of DEMES using silicone type elastomer. Based on the result, two and four-finger gripper are developed.

 

 

 

This work has been done as a collaboration work with the EPFL-LMTS, and related information can be found on their website.

 

Variable Stiffness Materials

Soft robots are exciting to many applications because they can deform, allowing them to conform to many different surfaces or readily change their shape. However, because they are soft, they can have difficulty holding their position or shape under high external loads. This is why we are interested in developing materials that can controllably change from very soft and flexible to rigid and strong.

One solution that we have developed is a composite material composed of a rigid low-melting-point-alloy (LMPA) microstructure embedded in soft poly(dimethylsiloxane) (PDMS). This material can transition between rigid and soft states by controlling the phase of the LMPA (T= 47°C) through efficient, direct Joule-heating of the LMPA microstructure. This composite material demonstrates a relative stiffness change of >25x (elastic modulus is 40 MPa when LMPA is solid and 1.5 MPa when LMPA is liquid) and a fast transition from rigid to soft states (<1 s) at low power (<500 mW). Additionally, the material possesses inherent state (soft and rigid) and strain sensing (Gauge Factor = 0.8) based on resistance changes.

 

Publications

2019

V. Cacucciolo; J. Shintake; Y. Kuwajima; S. Maeda; D. Floreano et al. : Stretchable pumps for soft machines; Nature. 2019-08-22. DOI : 10.1038/s41586-019-1479-6.

2018

V. Ramachandran; J. Shintake; D. Floreano : All‐Fabric Wearable Electroadhesive Clutch; Advanced Materials Technologies. 2018-10-23. DOI : 10.1002/admt.201800313.
A. Tonazzini; J. Shintake; C. Rognon; V. Ramachandran; S. Mintchev et al. : Variable stiffness strip with strain sensing for wearable robotics. 2018-07-09. 2018 IEEE International Conference on Soft Robotics (RoboSoft), Livorno, April 24-28, 2018. p. 485-490. DOI : 10.1109/ROBOSOFT.2018.8405373.
J. Shintake; V. Cacucciolo; H. Shea; D. Floreano : Soft Biomimetic Fish Robot Made of Dielectric Elastomer Actuators; Soft Robotics. 2018-06-29. DOI : 10.1089/soro.2017.0062.
S. Mintchev; J. Shintake; D. Floreano : Bioinspired dual-stiffness origami; Science Robotics. 2018. DOI : 10.1126/scirobotics.aau0275.
J. Shintake; V. Cacucciolo; D. Floreano; H. Shea : Soft Robotic Grippers; Advanced Materials. 2018. DOI : 10.1002/adma.201707035.
J. Shintake; E. Piskarev; S. Jeong; D. Floreano : Ultra-stretchable strain sensors using carbon black-filled elastomer composites and comparison of capacitive versus resistive sensors; Advanced Materials Technologies. 2018. DOI : 10.1002/admt.201700284.

2017

M. Mundus; B. Venkataramanachar; R. Gehlhaar; M. Kohlstaedt; B. Niesen et al. : Spectrally resolved nonlinearity and temperature dependence of perovskite solar cells; Solar Energy Materials And Solar Cells. 2017. DOI : 10.1016/j.solmat.2017.07.013.
D. Zappetti; S. Mintchev; J. Shintake; D. Floreano : Bio-inspired Tensegrity Soft Modular Robots. 2017. Living Machines 2017, Palo Alto, California, USA, July 25-28, 2017. p. 497-508.
T. A. P. Paschal; J. Shintake; S. Mintchev; D. Floreano : Development of Bio-inspired Underwater Robot with Adaptive Morphology Capable of Multiple Swimming Modes. 2017. IEEE/RSJ International Conference on Intelligent Robots and Systems, Vancouver, Canada, September 24–28.
J. Shintake; H. A. Sonar; E. Piskarev; J. Paik; D. Floreano : Soft Pneumatic Gelatin Actuator for Edible Robotics. 2017. IEEE/RSJ International Conference on Intelligent Robots and Systems, Vancouver, Canada, September 24–28.
D. Floreano; S. Mintchev; J. Shintake : Foldable Drones: from Biology to Technology. 2017. SPIE Bioinspiration, Biomimetics, and Bioreplication, Portland, Oregon, March 2017. p. 1016203-1-1016203-6. DOI : 10.1117/12.2259931.

2016

J. Shintake; H. Shea; D. Floreano : Biomimetic Underwater Robots Based on Dielectric Elastomer Actuators. 2016. IEEE/RSJ International Conference on Intelligent Robots and Systems, Daejeon, Korea, October 9-14. p. 4957-4962.
A. Tonazzini; S. Mintchev; B. Schubert; B. Mazzolai; J. Shintake et al. : Variable Stiffness Fiber with Self-Healing Capability; Advanced Materials. 2016. DOI : 10.1002/adma.201602580.
H. Shea; A. Koh; I. Graz; J. Shintake : Dielectric Elastomers as EAPs: How to start experimenting with them; Electromechanically Active Polymers; Springer, 2016.
H. Shea; J. Shintake; D. Floreano : Soft compliant gripper for safe manipulation of extremely fragile objects; SPIE Newsroom. 2016. DOI : 10.1117/2.1201603.006409.
J. Shintake / D. Floreano; H. Shea (Dir.) : Functional Soft Robotic Actuators Based on Dielectric Elastomers. Lausanne, EPFL, 2016. DOI : 10.5075/epfl-thesis-6855.
J. Shintake; S. Rosset; B. E. Schubert; D. Floreano; H. Shea : Versatile soft grippers with intrinsic electroadhesion based on multifunctional polymer actuators; Advanced Materials. 2016. DOI : 10.1002/adma.201504264.

2015

J. Shintake; B. E. Schubert; S. Rosset; H. Shea; D. Floreano : Variable Stiffness Actuator for Soft Robotics Using Dielectric Elastomer and Low-Melting-Point Alloy. 2015. International Conference on Intelligent Robots and Systems, Hamburg, Germany, September 28 - October 02, 2015. p. 1097-1102. DOI : 10.1109/IROS.2015.7353507.
J. Shintake; S. Rosset; B. E. Schubert; S. Mintchev; D. Floreano et al. : DEA for soft robotics: 1-gram actuator picks up a 60-gram egg. 2015. Electroactive Polymer Actuators and Devices (EAPAD), San Diego, March 2015. p. 94301S. DOI : 10.1117/12.2084043.
J. Shintake; S. Rosset; B. E. Schubert; D. Floreano; H. Shea : A Foldable Antagonistic Actuator; IEEE/ASME Transactions on Mechatronics. 2015. DOI : 10.1109/TMECH.2014.2359337.
S. Araromi; I. Gavrilovich; J. Shintake; S. Rosset; M. Richard et al. : Rollable Multisegment Dielectric Elastomer Minimum Energy Structures for a Deployable Microsatellite Gripper; IEEE/ASME Transactions on Mechatronics. 2015. DOI : 10.1109/TMECH.2014.2329367.

2014

S. Rosset; S. Araromi; J. Shintake; H. Shea : Model and design of dielectric elastomer minimum energy structures; Smart Materials and Structures. 2014. DOI : 10.1088/0964-1726/23/8/085021.
J. M. Germann; B. E. Schubert; D. Floreano : Stretchable Electroadhesion for Soft Robots. 2014. IEEE/RSJ International Conference on Intelligent Robots and Systems, Chicago, Illinois, USA, September 14-18, 2014.
S. Araromi; I. Gavrilovich; J. Shintake; S. Rosset; H. Shea : Towards a deployable satellite gripper based on multisegment dielectric elastomer minimum energy structures. 2014. Electroactive Polymer Actuators and Devices (EAPAD) 2014, San Diego, March 2014. p. 90562G. DOI : 10.1117/12.2044667.

2013

J. Shintake; S. Rosset; B. E. Schubert; D. Floreano; H. Shea : Dielectric Elastomer Actuators for soft-grasping ; International Workshop on Soft Robotics and Morphological Computation, Centro Stefano Franscini (CSF), Monte Verità, Ascona, Switzerland, July 14-19, 2013.
B. E. Schubert; D. Floreano : Variable stiffness material based on rigid low-melting-point-alloy-microstructures embedded in soft poly(dimethylsiloxane) (PDMS); RSC Advances. 2013. DOI : 10.1039/c3ra44412k.
J. Shintake; S. Rosset; D. Floreano; H. Shea : Artificial muscles for soft robots ; Festival de robotique.
J. Shintake; S. Rosset; D. Floreano; H. Shea : Effect of mechanical parameters on dielectric elastomer minimum energy structures. 2013. Electroactive Polymer Actuators and Devices (EAPAD), San Diego, USA, March 10, 2013. p. 86872V. DOI : 10.1117/12.2009368.

2012

J. Shintake; S. Rosset; D. Floreano; H. Shea : A soft robotic actuator using dielectric minimum energy structures ; 2nd International Conference on Electromechanically Active Polymer (EAP) transducers & artificial muscles, Potsdam (Berlin), Germany, May 29-30, 2012.