scholarly journals An Origami Flexiball-Inspired Metamaterial Actuator and Its In-Pipe Robot Prototype

Actuators ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 67
Author(s):  
Fuwen Hu ◽  
Tian Li
Keyword(s):  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Multiple Degrees Of Freedom ◽  
Soft Actuator ◽  
Structure Building ◽  
Magnetically Actuated ◽  
Mechanical Metamaterials ◽  
New Type ◽  
Soft Actuators ◽  
Magnetoactive Elastomer

Usually, polyhedra are viewed as the underlying constructive cells of packing or tilling in many disciplines, including crystallography, protein folding, viruses structure, building architecture, etc. Here, inspired by the flexible origami polyhedra (commonly called origami flexiballs), we initially probe into their intrinsic metamaterial properties and robotized methods from fabrication to actuation. Firstly, the topology, geometries and elastic energies of shape shifting are analyzed for the three kinds of origami flexiballs with extruded outward rhombic faces. Provably, they meet the definitions of reconfigurable and transformable metamaterials with switchable stiffness and multiple degrees of freedom. Secondly, a new type of soft actuator with rhombic deformations is successfully put forward, different from soft bionic deformations like elongating, contracting, bending, twisting, spiraling, etc. Further, we redesign and fabricate the three-dimensional (3D) printable structures of origami flexiballs considering their 3D printability and foldability, and magnetically actuated them through the attachment of magnetoactive elastomer. Lastly, a fully soft in-pipe robot prototype is presented using the origami flexiball as an applicable attempt. Experimental work clearly suggests that the presented origami flexiball robot has good adaptability to various pipe sizes, and also can be easily expanded to different scales, or reconfigured into more complex metastructures by assembly. In conclusion, this research provides a newly interesting and illuminating member for the emerging families of mechanical metamaterials, soft actuators and soft robots.

scholarly journals Design, Fabrication, and Testing of a Novel 3D 3-Fingered Electrothermal Microgripper with Multiple Degrees of Freedom

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 444
Author(s):  
Guoning Si ◽  
Liangying Sun ◽  
Zhuo Zhang ◽  
Xuping Zhang
Keyword(s):  
Degrees Of Freedom ◽  
Dynamic Properties ◽  
Three Dimensional ◽  
Polyimide Film ◽  
Zebrafish Embryos ◽  
Multiple Degrees Of Freedom ◽  
Electrothermal Actuator ◽  
3D Space ◽  
Pick And Place

This paper presents the design, fabrication, and testing of a novel three-dimensional (3D) three-fingered electrothermal microgripper with multiple degrees of freedom (multi DOFs). Each finger of the microgripper is composed of a V-shaped electrothermal actuator providing one DOF, and a 3D U-shaped electrothermal actuator offering two DOFs in the plane perpendicular to the movement of the V-shaped actuator. As a result, each finger possesses 3D mobilities with three DOFs. Each beam of the actuators is heated externally with the polyimide film. The durability of the polyimide film is tested under different voltages. The static and dynamic properties of the finger are also tested. Experiments show that not only can the microgripper pick and place microobjects, such as micro balls and even highly deformable zebrafish embryos, but can also rotate them in 3D space.

Time-varying mesh stiffness calculation for gear pairs with misalignment errors in multiple degrees of freedom based on an analytical method

2021 ◽  
pp. 095440622110392
Author(s):  
Qi Wen ◽  
Qi Chen ◽  
Qungui Du ◽  
Yong Yang
Keyword(s):  
Analytical Model ◽  
Contact Line ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Single Pair ◽  
Time Varying ◽  
Mesh Stiffness ◽  
Position Change ◽  
Multiple Degrees Of Freedom ◽  
Effective Contact

Misalignment errors (MEs) in multiple degrees of freedom (multi-DOFs) at the mesh position will lead to a change in the time-varying mesh stiffness (TVMS) and then affect the dynamic behaviour of gear pairs. Therefore, a new, more rapid, three-dimensional analytical model for TVMS calculation for gear pairs with three rotational and three translational MEs is established in this paper, and a new solution method based on potential energy theory is presented. In addition, the correctness of the new model is verified by the finite element method (FEM). Moreover, the effective contact line, uneven distribution of mesh force on the contact line, and mesh position change are taken into account. Finally, the TVMS under different ME conditions is calculated with the new analytical model. The results showed that the different MEs have dissimilar effects on the TVMS, and the relationship between the ME and TVMS is nonlinear. In addition, the region of single-pair and double-pair teeth in contact would also change with ME.

Design and optimization of actuator for multi-joint soft rehabilitation glove

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xinjie Wang ◽  
Yan Cheng ◽  
Huadong Zheng ◽  
Yihao Li ◽  
Caidong Wang
Keyword(s):  
Constitutive Model ◽  
Element Model ◽  
Longitudinal Section ◽  
Bending Test ◽  
Hand Rehabilitation ◽  
Content Type ◽  
Design And Optimization ◽  
Soft Actuator ◽  
New Type ◽  
Soft Actuators

Purpose Currently, rehabilitation medical care is expensive, requires a large number of rehabilitation therapist and which can only limit in the fixed location. In addition, there is a lack of research on the structure optimization and theoretical analysis of soft actuators for hand rehabilitation. In view of the problems above, this paper aims to propose a cheap, portable, wearable soft multiple joints rehabilitation glove. Design/methodology/approach First, this paper determined the hyperelastic constitutive model by material tensile test. Second, the soft actuator’s internal longitudinal section shape was optimized through the comparison of three diverse chamber structures. Meanwhile, the motion model of the soft actuator is established by the finite element model analysis method. Then, this paper established the constitutive model of the soft actuator according to the torque equilibrium equation and analyzed the relationship between the soft actuator’s bending angle and the input air pressure. This paper has verified that the theoretical model is correct through the soft actuator bending test. Finally, rehabilitation gloves were manufactured according to the model and the rehabilitation performance and grasping ability of gloves were verified through experiments. Findings The optimization results show that the internal semicircular cavity has better performance. Then, the actuator performance is better after adding the external arc structure and optimizing the physical dimension. The experimental results show that the trajectory of the actuator conforms to the mathematical model and rehabilitation gloves can meet the needs of rehabilitation treatment. Practical implications Rehabilitation gloves made of actuators can help patients with hand dysfunction in daily rehabilitation training. Then, it can also assist patients with some fine and complicated hand movements. Originality/value This paper proposes a new type of soft rehabilitation glove, which is composed of new soft actuators and adapting pieces. The new actuator is small enough to be fitted to the knuckle of the glove to move each joint of the finger.

scholarly journals Application and Analysis of an Ionic Liquid Gel in a Soft Robot

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Chenghong Zhang ◽  
Bin He ◽  
Zhipeng Wang ◽  
Yanmin Zhou ◽  
Aiguo Ming
Keyword(s):  
Ionic Liquid ◽  
Uv Light ◽  
Electroactive Polymers ◽  
Electroactive Polymer ◽  
Soft Robot ◽  
Polymer Gel ◽  
Basic Module ◽  
Soft Actuator ◽  
New Type ◽  
Soft Actuators

Due to their light weight, flexibility, and low energy consumption, ionic electroactive polymers have become a hotspot for bionic soft robotics and are ideal materials for the preparation of soft actuators. Because the traditional ionic electroactive polymers, such as ionic polymer-metal composites (IPMCs), contain water ions, a soft actuator does not work properly upon the evaporation of water ions. An ionic liquid polymer gel is a new type of ionic electroactive polymer that does not contain water ions, and ionic liquids are more thermally and electrochemically stable than water. These liquids, with a low melting point and a high ionic conductivity, can be used in ionic electroactive polymer soft actuators. An ionic liquid gel (ILG), a new type of soft actuator material, was obtained by mixing 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4), hydroxyethyl methacrylate (HEMA), diethoxyacetophenone (DEAP) and ZrO2 and then polymerizing this mixture into a gel state under ultraviolet (UV) light irradiation. An ILG soft actuator was designed, the material preparation principle was expounded, and the design method of the soft robot mechanism was discussed. Based on nonlinear finite element theory, the deformation mechanism of the ILG actuator was deeply analyzed and the deformation of the soft robot when grabbing an object was also analyzed. A soft robot was designed with the soft actuator as the basic module. The experimental results show that the ILG soft robot has good driving performance, and the soft robot can grab a 105 mg object at an input voltage of 3.5 V.

Prediction of Blade Flutter in a Tuned Rotor

1985 ◽  
Author(s):  
Jianmin Xu ◽  
Zhaohong Song
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Rotating Blades ◽  
Multiple Degrees Of Freedom ◽  
Strip Theory ◽  
Blade Flutter ◽  
Good Agreement

This paper is about blade flutter in a tuned rotor. With the aid of the combination of three dimensional structural finite element method, two dimensional aerodynamical finite difference method and strip theory, the quasi-steady models in which two degrees of freedom for a single wing were considered have been extended to multiple degrees of freedom for the whole blade in a tuned rotor. The eigenvalues solved from the blade motion equation have been used to judge whether the system is stable or not. The calculating procedure has been formed and using it the first stage rotating blades of a compressor where flutter had occurred, have been predicted. The numerical flutter boundaries have good agreement with the experimental ones.

scholarly journals Control-Oriented Modelling of a 3D-Printed Soft Actuator

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 71 ◽  
Author(s):  
Ali Zolfagharian ◽  
Akif Kaynak ◽  
Sui Yang Khoo ◽  
Jun Zhang ◽  
Saeid Nahavandi ◽  
...  
Keyword(s):  
3D Printing ◽  
Dynamic Models ◽  
Three Dimensional ◽  
Input Voltage ◽  
Soft Actuator ◽  
Voltage Variation ◽  
Sophisticated Model ◽  
3D Printed ◽  
Rc Circuit ◽  
Soft Actuators

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.

scholarly journals Recent Developments on Modeling for a 3-DOF Micro-Hand Based on AI Methods

Micromachines ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 792
Author(s):  
Shuhei Kawamura ◽  
Mingcong Deng
Keyword(s):  
Artificial Intelligence ◽  
Degrees Of Freedom ◽  
Air Pressure ◽  
Support Vector ◽  
Input Output ◽  
Soft Actuator ◽  
Flexible Materials ◽  
Recent Developments ◽  
Soft Actuators ◽  
Three Degrees Of Freedom

Recently, soft actuators have been expected to have many applications in various fields. Most of the actuators are composed of flexible materials and driven by air pressure. The 3-DOF micro-hand, which is a kind of soft actuator, can realize a three degrees of freedom motion by changing the applied air pressure pattern. However, the input–output relation is nonlinear and complicated. In previous research, a model of the micro-hand was proposed, but an error between the model and the experimental results was large. In this paper, modeling for the micro-hand is proposed by using multi-output support vector regression (MSVR) and ant colony optimization (ACO), which is one of the artificial intelligence (AI) methods. MSVR estimates the input–output relation of the micro-hand. ACO optimizes the parameters of the MSVR model.

Dynamical Characteristics of a Hydraulic Soft Actuator With Three Degrees of Freedom

2021 ◽  
Author(s):  
Qing Xie ◽  
Tao Wang ◽  
Shiqiang Zhu
Keyword(s):  
Dynamic Model ◽  
Degrees Of Freedom ◽  
Soft Actuator ◽  
Dynamical Characteristics ◽  
Geometrical Features ◽  
Highly Nonlinear ◽  
Series Of Experiments ◽  
Soft Actuators ◽  
Modeling Of Dynamics ◽  
Three Degrees Of Freedom

Abstract In recent years, increasing attention and expanding research have been devoted to the study and application of soft actuators. Inherent compliance equips soft actuators with such advantages as incomparable flexibility, good environmental adaptability, safe interaction with the environment, etc. However, the highly nonlinear also bring challenges to modeling of dynamics. This study aims to explore the dynamical characteristics of an underwater hydraulic soft actuator. The actuator has three fiber-reinforced elastomer chambers distributed symmetrically inside. By controlling the pressure in the chambers through a hydraulic power system, the actuator can achieve spatial motion with three degrees of freedom. To describe the relationship between the input pressure combination and the actuator movement, a dynamic model considering the nonlinearity of viscoelastic material is developed based on Lagrangian method and constant curvature hypothesis. A series of experiments are carried out, including single-chamber actuation and multi-chamber actuation. The test results verify the effectiveness and precision of the model. Finally, the effects of the geometrical features on dynamic response are investigated through model-based simulation, which can provide guidance to parameter optimization. The proposed dynamic model can also contribute to behavior analysis, performance prediction, and motion control of the hydraulic soft actuator.

Characteristics of Micro Pump Driven by Conducting Polymer Soft Actuator

2008 ◽  
Author(s):  
Yoshitaka Naka ◽  
Masaki Fuchiwaki ◽  
Kazuhiro Tanaka
Keyword(s):  
Conducting Polymer ◽  
Three Dimensional ◽  
High Viscosity ◽  
Soft Actuator ◽  
Micro Pump ◽  
Micro Flow ◽  
Soft Actuators ◽  
Opening And Closing ◽  
Viscosity Fluid ◽  
Energy Consumption Rate

The development of micro pumps are actively conducted in recent years. A micro pump used for μ-TAS transports at a micro flow rate with a high precision. Moreover, it is also needed to transport high-viscosity fluid since there are various types of drugs to be transported. Micro pumps with various driving systems have been developed so far. In this study, the authors propose a micro pump with soft actuators by conducting polymers as a driving source. We have realized the conducting polymer soft actuator with opening and closing movement. The opening and closing movement of the soft actuator in which the cation driving layer is arranged inside becomes large since the anion driving layer arranged outside drives predominantly. The opening and closing movement is realized by the characteristic that three dimensional deformations are suppressed by setting slits in a sheet-shaped soft actuator and straight-shaped soft actuators in the slits synchronize and deform. It is possible to build a micro pump that transports fluid in one direction by a micro pump with two soft actuators with opening and closing movement and that it can transport fluid even with the viscosity that is 140 times as large as that of water in addition. The micro pump with two soft actuators with opening and closing movement proposed in this paper transports fluid with an energy consumption rate less than half those of others.

Design and application of integrated parabolic soft actuator

2019 ◽  
Vol 46 (6) ◽  
pp. 792-799
Author(s):  
Dong Liu ◽  
Minghao Wang ◽  
Ming Cong
Keyword(s):  
Stress Concentration ◽  
Fem Analysis ◽  
Distribution Model ◽  
Content Type ◽  
Soft Actuator ◽  
Distributed Structure ◽  
Air Chamber ◽  
New Type ◽  
Circular Ladder ◽  
Soft Actuators

Purpose The purpose of this paper is to solve the common problems of outer phenomenon and stress concentration among pneumatic networks soft actuators. Design/methodology/approach On the basis of imitating the caterpillar structure, the new soft actuator adopts the integral circular ladder structure instead of the traditional independent distributed structure as the air chamber. Through the comparison of several different structures, the parabolic in-wall curve is found to be fit for designing the optimal integrated chamber structure of the soft actuator. The curve function of each ladder chamber is computed based on the torque distribution model, aiming to decrease the terminal deformation. Meanwhile, the FEM analysis method is applied to establish the motion model of the integrated parabolic ladder soft actuator. The model’s accuracy, as well as structure’s deformation and stress, are verified. Findings Compared with the FEM data, the experimental data indicate that the new soft actuator has no obvious outer phenomenon, the maximum stress decreases and the stiffness increases. The new actuator is applied for designing a flexible gripper to grasp objects of different shapes and sizes. The gripper can grasp objects of 52.6 times its own mass. Practical implications The designed gripper is available for flexible production in various fields, such as capturing fruits of different sizes, soft foods or parts with complex shapes. Originality/value This paper proposes a new type soft actuator, which provides a solution for exploring the field of the soft robot. The problems of outer phenomenon and stress concentration are suppressed with pneumatic networks soft actuators.

Sign in / Sign up

Export Citation Format

Share Document