Design and Characterization of a 3D Printed Soft Pneumatic Actuator

Morales, Ditzia Susana Garcia; Ibrahim, Serhat; Cao, Benjamin-Hieu; Raatz, Annika

doi:10.1007/978-3-030-55061-5_55

Cited by 9 publications

(4 citation statements)

References 16 publications

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“…We presented the characterisation of the bending motion via computer vision. Likewise, the maximum bending angles are 123.9 • , 115 • and 28.91 • when a single channel is activated independently and when two or three channels are activated simultaneously, obtaining deformation values in the range of previously reported modules [19,[21][22][23][24][25]. Thus, the module exhibits excellent mobility.…”

Section: Discussionsupporting

confidence: 58%

“…However, when more motions are necessary, this method becomes unpractical due to the complexity of joining more than two actuators. Multiple motions soft actuators have been proposed [19][20][21][22][23][24] considering chambers or at least three independent channels, distributed homogeneously in the body, resulting in motions of elongation and multiple bending and performing deformations from 36 • to less than 160 • [19,[21][22][23][24][25][26] (depending on the angle measurement method). The motion variation depends on the method of measurement, manufacturing material and actuator geometry.…”

Section: Introductionmentioning

confidence: 99%

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Design and characterisation of a multi-DOF soft pneumatic module

Santacruz-Mondragon,

Sandoval-Castro,

Ibrahim

et al. 2023

Robotica

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Bending and elongation have been some of the most studied motions in soft actuators due to the variety of their applications. For that matter, multi-DOF actuators have been developed with the purpose to generate different movements in a single actuator, mainly bending. However, these actuators are still limited in mobility range, and some of them do not perform continuous curvatures. This paper presents the design, characterisation and implementations of a multi-DOF soft pneumatic module. The internal structure of the proposed module is composed of four channels, which generate bending in several directions. The finite element method analysis demonstrates that the actuator performs continuous curvatures for different pressure values. We present a repeatable and easy manufacturing process using the casting technique, considering the material Ecoflex 00-50; as well as the kinematic model of the actuator, taking into consideration two bending Degrees of Freedom (DOFs). Furthermore, we performed bending characterisation for all possible combinations of the four channels via computer vision, demonstrating a wide mobility range and performing continuous curvatures. Additionally, we evaluated the kinematic model with characterisation data, obtaining the angular and cartesian relationship between the pressure and continuous curvatures. On the other hand, the authors propose the design of a modular soft manipulator based on two multi-DOF modules. The kinematic model is reported. In addition, we implement a motion sequence in the manipulator to pick and place tasks.

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Section: Discussionsupporting

confidence: 58%

Section: Introductionmentioning

confidence: 99%

Design and characterisation of a multi-DOF soft pneumatic module

Santacruz-Mondragon,

Sandoval-Castro,

Ibrahim

et al. 2023

Robotica

Self Cite

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“…If there is a construction with high stiffness in the longitudinal side, one can set l a l 0 constant. This is the case for the 3D printed PneuNet actuator from Garcia et al (2020). While the chambers lengthen and shorten during the bending of the actuators, the central axis does not change in length.…”

Section: Parameter Of Actuator Modelmentioning

confidence: 84%

“…A decisive factor determining the movement of soft pneumatic actuators is their design. New actuator designs and mechanisms have been developed for this field of research [Runge and Raatz (2017), Galloway et al (2013) and Garcia et al (2020)]. The soft and flexible structures with mostly nonlinear material properties and hyperelasticity present a challenge for modeling, sensing and control.…”

Section: Introductionmentioning

confidence: 99%

Modeling and Reconstruction of State Variables for Low-Level Control of Soft Pneumatic Actuators

Ibrahim¹,

Krause²,

Olbrich³

et al. 2021

Front. Robot. AI

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To further advance closed-loop control for soft robotics, suitable sensor and modeling strategies have to be investigated. Although there are many flexible and soft sensors available, the integration into the actuator and the use in a control loop is still challenging. Therefore, a state-space model for closed-loop low-level control of a fiber-reinforced actuator using pressure and orientation measurement is investigated. To do so, the integration of an inertial measurement unit and geometric modeling of actuator is presented. The piecewise constant curvature approach is used to describe the actuator’s shape and deformation variables. For low-level control, the chamber’s lengths are reconstructed from bending angles with a geometrical model and the identified material characteristics. For parameter identification and model validation, data from a camera tracking system is analyzed. Then, a closed-loop control of pressure and chambers’ length of the actuator is investigated. It will be shown, that the reconstruction model is suitable for estimating the state variables of the actuator. In addition, the use of the inertial measurement unit will demonstrate a cost-effective and compact sensor for soft pneumatic actuators.

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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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Design and Characterization of a 3D Printed Soft Pneumatic Actuator

Cited by 9 publications

References 16 publications

Design and characterisation of a multi-DOF soft pneumatic module

Design and characterisation of a multi-DOF soft pneumatic module

Modeling and Reconstruction of State Variables for Low-Level Control of Soft Pneumatic Actuators

Injection Molding of Soft Robots

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