Simulation and Validation of Fully 3D Printed Soft Actuators

Author(s):  
Steffi Torres ◽  
Julio San Martin ◽  
Brittany Newell ◽  
Jose Garcia

Abstract Flexible actuators are a growing class of devices implemented in soft robotic applications, medical devices and processes involving food and pharmaceutical products. Such actuators have traditionally been manufactured using casting processes or other conventional methods requiring more than one fabrication step. The arrival of flexible 3D printing materials and 3D printing techniques has facilitated the creation of these flexible actuators via additive manufacturing. The work presented in this article displays the analytical characterization and experimental validation of two materials and two actuator designs. The first case presents a finite element analysis (FEA) simulated model of a bellows actuator using a photocurable flexible resin (TangoPlus FLX930) and studies the effect of printing orientation on the simulation. The simulation used a 5 parameter Mooney-Rivlin model to predict the strain behavior of the actuator under hydrostatic pressure. A second case is presented where a Thermoplastic Polyurethane actuator was 3D printed and simulated using the same FEA model and a second calibration of the Mooney-Rivlin 5 parameter model. In both cases experimental data was used to calibrate and validate the simulation. The resulting simulated strain was consistent when the printing orientation of actuators was parallel (0 degrees) to the strain direction of the actuators. Results were less consistent when a print orientation of 45 degrees was applied.

2021 ◽  
Vol 11 (4) ◽  
pp. 70-79
Author(s):  
Dino Dominic Forte Ligutan ◽  
Argel Alejandro Bandala ◽  
Jason Limon Española ◽  
Richard Josiah Calayag Tan Ai ◽  
Ryan Rhay Ponce Vicerra ◽  
...  

The development of a novel 3D-printed three-claw robotic gripper shall be described in this paper with the goal of incorporating various design considerations. Such considerations include the grip reliability and stability, grip force maximization, wide object grasping capability. Modularization of its components is another consideration that allows its parts to be easily machined and reusable. The design was realized by 3D printing using a combination of tough polylactic acid (PLA) material and thermoplastic polyurethane (TPU) material. In practice, additional tolerances were also considered for 3D printing of materials to compensate for possible expansion or shrinkage of the materials used to achieve the required functionality. The aim of the study is to explore the design and eventually deploy the three-claw robotic gripper to an actual robotic arm once its metal work fabrication is finished.


Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2034 ◽  
Author(s):  
Tomasz Kozior ◽  
Al Mamun ◽  
Marah Trabelsi ◽  
Martin Wortmann ◽  
Sabantina Lilia ◽  
...  

Electrospinning is a frequently used method to prepare air and water filters. Electrospun nanofiber mats can have very small pores, allowing for filtering of even the smallest particles or molecules. In addition, their high surface-to-volume ratio allows for the integration of materials which may additionally treat the filtered material through photo-degradation, possess antimicrobial properties, etc., thus enhancing their applicability. However, the fine nanofiber mats are prone to mechanical damage. Possible solutions include reinforcement by embedding them in composites or gluing them onto layers that are more mechanically stable. In a previous study, we showed that it is generally possible to stabilize electrospun nanofiber mats by 3D printing rigid polymer layers onto them. Since this procedure is not technically easy and needs some experience to avoid delamination as well as damaging the nanofiber mat by the hot nozzle, here we report on the reversed technique (i.e., first 3D printing a rigid scaffold and subsequently electrospinning the nanofiber mat on top of it). We show that, although the adhesion between both materials is insufficient in the case of a common rigid printing polymer, nanofiber mats show strong adhesion to 3D printed scaffolds from thermoplastic polyurethane (TPU). This paves the way to a second approach of combining 3D printing and electrospinning in order to prepare mechanically stable filters with a nanofibrous surface.


2019 ◽  
Vol 7 (16) ◽  
pp. 4692-4701 ◽  
Author(s):  
Jahan Zeb Gul ◽  
Memoon Sajid ◽  
Kyung Hyun Choi

A novel, highly flexible and electrically resistive-type strain sensor with a special three-dimensional conductive network was 3D printed using a composite of conductive graphene pellets and flexible thermoplastic polyurethane (TPU) pellets.


Micromachines ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 46 ◽  
Author(s):  
Claudio Manganiello ◽  
David Naso ◽  
Francesco Cupertino ◽  
Orazio Fiume ◽  
Gianluca Percoco

The present research aims to exploit commercially available materials and machines to fabricate multilayer, topologically designed transducers, which can be embedded into mechanical devices, such as soft or rigid grippers. Preliminary tests on the possibility of fabricating 3D-printed transducers using a commercial conductive elastomeric filament, carbon black-filled thermoplastic polyurethane, are presented. The commercial carbon-filled thermoplastic polyurethane (TPU), analyzed in the present paper, has proven to be a candidate material for the production of 3D printed displacement sensors. Some limitations in fabricating the transducers from a 2.85 mm filament were found, and comparisons with 1.75 mm filaments should be conducted. Moreover, further research on the low repeatability at low displacements and the higher performance of the hollow structure, in terms of repeatability, must be carried out. To propose an approach that can very easily be reproduced, only commercial filaments are used.


Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 71 ◽  
Author(s):  
Ali Zolfagharian ◽  
Akif Kaynak ◽  
Sui Yang Khoo ◽  
Jun Zhang ◽  
Saeid Nahavandi ◽  
...  

A new type of soft actuator was developed by using hydrogel materials and three-dimensional (3D) printing technology, attracting the attention of researchers in the soft robotics field. Due to parametric uncertainties of such actuators, which originate in both a custom design nature of 3D printing as well as time and voltage variant characteristics of polyelectrolyte actuators, a sophisticated model to estimate their behaviour is required. This paper presents a practical modeling approach for the deflection of a 3D printed soft actuator. The suggested model is composed of electrical and mechanical dynamic models while the earlier version describes the actuator as a resistive-capacitive (RC) circuit. The latter model relates the ionic charges to the bending of an actuator. The experimental results were acquired to estimate the transfer function parameters of the developed model incorporating Takagi-Sugeno (T-S) fuzzy sets. The proposed model was successful in estimating the end-point trajectory of the actuator, especially in response to a broad range of input voltage variation. With some modifications in the electromechanical aspects of the model, the proposed modelling method can be used with other 3D printed soft actuators.


Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6541
Author(s):  
Marcin Białek ◽  
Cezary Jędryczka ◽  
Andrzej Milecki

This paper presents a study of penetrating a pin into a magnetorheological fluid (MR) cushion focused on the force measurement. The research is supported by detailed finite element analysis (FEA) of the magnetic field distributions in several magnetic field exciters applied to control rheological properties of the MR inside the cushion. The cushion is a part of the finger pad of the jaw soft-rigid gripper and was made of thermoplastic polyurethane (TPU) using 3D printing technology. For the pin-penetrating setup, the use of a holding electromagnet and a magnetic holder were considered and verified by simulation as well as experiment. In further simulation studies, two design solutions using permanent magnets as the source of the magnetic field in the cushion volume to control MR fluid viscosity were considered. The primary aim of the study was to analyze the potential of using an MR fluid in a cushion pad and to investigate the potential for changing its viscosity using different magnetic field sources. The analysis included magnetic field simulations and tests of pin penetration in the cushion as an imitation of object grasping. Thus, an innovative application of 3D printing and TPU to work with MR fluid is proposed.


Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 305
Author(s):  
Linda Ritzen ◽  
Vincenzo Montano ◽  
Santiago J. Garcia

The use of self-healing (SH) polymers to make 3D-printed polymeric parts offers the potential to increase the quality of 3D-printed parts and to increase their durability and damage tolerance due to their (on-demand) dynamic nature. Nevertheless, 3D-printing of such dynamic polymers is not a straightforward process due to their polymer architecture and rheological complexity and the limited quantities produced at lab-scale. This limits the exploration of the full potential of self-healing polymers. In this paper, we present the complete process for fused deposition modelling of a room temperature self-healing polyurethane. Starting from the synthesis and polymer slab manufacturing, we processed the polymer into a continuous filament and 3D printed parts. For the characterization of the 3D printed parts, we used a compression cut test, which proved useful when limited amount of material is available. The test was able to quasi-quantitatively assess both bulk and 3D printed samples and their self-healing behavior. The mechanical and healing behavior of the 3D printed self-healing polyurethane was highly similar to that of the bulk SH polymer. This indicates that the self-healing property of the polymer was retained even after multiple processing steps and printing. Compared to a commercial 3D-printing thermoplastic polyurethane, the self-healing polymer displayed a smaller mechanical dependency on the printing conditions with the added value of healing cuts at room temperature.


Soft Matter ◽  
2017 ◽  
Vol 13 (33) ◽  
pp. 5558-5568 ◽  
Author(s):  
Chao Yuan ◽  
Devin J. Roach ◽  
Conner K. Dunn ◽  
Quanyi Mu ◽  
Xiao Kuang ◽  
...  

We fabricate reversible shape changing soft actuators based on the hybrid 3D printing concept.


Author(s):  
Karl Jin Ang ◽  
Katherine S. Riley ◽  
Jakob Faber ◽  
Andres F. Arrieta

Using fused deposition modeling (FDM) 3D printing, we combine a bio-inspired bilayer architecture with distributed pre-stress and the shape memory behavior of polylactic acid (PLA) to manufacture shells with switchable bistability. These shells are stiff and monostable at room temperature, but become elastic and bistable with fast morphing when heated above their glass transition temperature. When cooled back down, the shells retain the configuration they were in at the elevated temperature and return to being stiff and monostable. These programmed deformations result from the careful design and control of how the filament is extruded by the printer and therefore, the resulting directional pre-stress. Parameter studies are presented on how to maximize the pre-stress for this application. The shells are analyzed using nonlinear finite element analysis. By leveraging the vast array of geometries accessible with 3D printing, this method can be extended to complex, multi-domain shells, including bio-inspired designs.


2017 ◽  
Vol 17 (07) ◽  
pp. 1740030 ◽  
Author(s):  
YADONG CHEN ◽  
TIANXING GONG ◽  
BOXUAN SUN ◽  
DEHAO SHANG

The state-of-the-art surgery makes it possible to transfer tissue from donor site to recipient sites for reconstruction. In particular, free fibula becomes one of the common methods to repair mandibular (i.e., lower jawbone) defects. To guide one individual surgery, the 3D printing and finite element analysis (FEA) technologies have been employed in this study. The personalized model of titanium plate with screws was designed on the basis of computed tomography data with the help of the reverse engineering technology and 3D computational model via the PRO/E software. In order to refine the model, FEA results were used to guide the operation plan. Finally, the 3D-printed scaffold was used in the surgery. In conclusion, 3D printing technology and FEA for mandibular reconstruction surgery guidance can achieve good matches among fibula, human mandible and titanium plates, restore mandible functions, reduce the operation time and improve the success rate of surgery. Furthermore, this technology gives more freedom for physicians to discuss surgical plans with patients.


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