scholarly journals Soft Actuator Model for a Soft Robot With Variable Stiffness by Coupling Pneumatic Structure and Jamming Mechanism

IEEE Access ◽  
2020 ◽  
Vol 8 ◽  
pp. 26356-26371 ◽  
Author(s):  
Feng-Yu Xu ◽  
Feng-You Jiang ◽  
Quan-Sheng Jiang ◽  
Yu-Xuan Lu
Keyword(s):  
Variable Stiffness ◽  
Soft Robot ◽  
Soft Actuator

scholarly journals Fully-Printable Soft Actuator with Variable Stiffness by Phase Transition and Hydraulic Regulations

Actuators ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 269
Author(s):  
Tingchen Liao ◽  
Manivannan Sivaperuman Kalairaj ◽  
Catherine Jiayi Cai ◽  
Zion Tsz Ho Tse ◽  
Hongliang Ren
Keyword(s):  
Transition Period ◽  
Shape Memory Polymer ◽  
Variable Stiffness ◽  
Pressure Variation ◽  
Soft Actuator ◽  
Output Force ◽  
Load Carrying ◽  
Force Variation ◽  
Stiffness Variation ◽  
Short Transition

Actuators with variable stiffness have vast potential in the field of compliant robotics. Morphological shape changes in the actuators are possible, while they retain their structural strength. They can shift between a rigid load-carrying state and a soft flexible state in a short transition period. This work presents a hydraulically actuated soft actuator fabricated by a fully 3D printing of shape memory polymer (SMP). The actuator shows a stiffness of 519 mN/mm at 20 ∘C and 45 mN/mm at 50 ∘C at the same pressure (0.2 MPa). This actuator demonstrates a high stiffness variation of 474 mN/mm (10 times the baseline stiffness) for a temperature change of 30 ∘C and a large variation (≈1150%) in average stiffness. A combined variation of both temperature (20–50 ∘C) and pressure (0–0.2 MPa) displays a stiffness variation of 501 mN/mm. The pressure variation (0–0.2 MPa) in the actuator also shows a large variation in the output force (1.46 N) at 50 ∘C compared to the output force variation (0.16 N) at 20 ∘C. The pressure variation is further utilized for bending the actuator. Varying the pressure (0–0.2 MPa) at 20 ∘C displayed no bending in the actuator. In contrast, the same variation of pressure at 50 ∘C displayed a bending angle of 80∘. A combined variation of both temperature (20–50 ∘C) and pressure (0–0.2 MPa) shows the ability to bend 80∘. At the same time, an additional weight (300 g) suspended to the actuator could increase its bending capability to 160∘. We demonstrated a soft robotic gripper varying its stiffness to carry objects (≈100 g) using two individual actuators.

An obstacle-avoiding and stiffness-tunable modular bionic soft robot

Robotica ◽  
2022 ◽  
pp. 1-15
Author(s):  
Zhaoyu Liu ◽  
Yuxuan Wang ◽  
Jiangbei Wang ◽  
Yanqiong Fei ◽  
Qitong Du
Keyword(s):  
Variable Stiffness ◽  
Air Pressure ◽  
Design Parameters ◽  
Soft Robot ◽  
Working Pressure ◽  
Obstacle Avoiding ◽  
Stiffness Model ◽  
Pass Through ◽  
Soft Actuators

Abstract The aim of this work is to design and model a novel modular bionic soft robot for crawling and crossing obstacles. The modular bionic soft robot is composed of several serial driving soft modules, each module is composed of two parallel soft actuators. By analyzing the influence of working pressure and manufacturing size on the stiffness of the modular bionic soft robot, the nonlinear variable stiffness model of the modular bionic soft robot is established. Based on this model, the spatial states and design parameters of the modular bionic soft robot are discussed when the modular bionic soft robot can pass through the obstacle. Experiments show that when the inflation air pressure of the modular bionic soft robot is 70 kPa, its speed can reach 7.89 mm/s and the height of obstacles passed by it can reach 42.8 mm. The feasibility of the proposed modular bionic soft robot and nonlinear variable stiffness model is verified by locomotion experiments.

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.

Development of Pneumatic Rotary Soft Actuator Made of Silicone Rubber

2001 ◽  
Vol 13 (1) ◽  
pp. 17-22 ◽  
Author(s):  
Toshiro Noritsugu ◽  
◽  
Mitsuhiko Kubota ◽  
Sadaharu Yoshimatsu
Keyword(s):  
Silicone Rubber ◽  
Control Algorithm ◽  
Compressed Air ◽  
Robot Hand ◽  
Soft Robot ◽  
Human Beings ◽  
Partial Difference ◽  
Soft Actuator ◽  
Fundamental Properties ◽  
Rotary Type

A soft actuator with inherent flexibility has been required to built up a soft mechanical drive system such as a human beings collaboration robot and a welfare machine. In this study, a rotary type soft actuator made of silicone rubber driven with compressed air has been developed. This actuator can realize the desired rotary operation by using the fiber reinforcement and the partial difference of stiffness owing to the rubber thickness. In this paper, the structure and operational principle of the actuator is described, and the fundamental properties of actuator are experimentally investigated. The experimental results show that the actuator has the sufficiently large operational angle and the dynamic characteristics of a damping and elasticity component. Its application to a soft robot finger and a robot hand are discussed. Owing to the flexibility of actuator, this hand can grasp unshaped or flexible objects without any complicated control algorithm. The availability of this actuator is confirmed through some experiments.

scholarly journals Design and Testing of a Soft Robot with Variable Stiffness Based on Jamming Principles

2020 ◽  
Vol 56 (23) ◽  
pp. 67
Author(s):  
XU Fengyu ◽  
JIANG Quansheng ◽  
JIANG Fengyou ◽  
SHEN Jingjin ◽  
WANG Xingsong ◽  
...  
Keyword(s):  
Variable Stiffness ◽  
Soft Robot ◽  
Design And Testing

scholarly journals Snake-like Soft Robot Using 2-Chambers Actuator

2018 ◽  
Vol 17 (1) ◽  
pp. 34-40 ◽  
Author(s):  
Hakim Q.A. Abdulrab ◽  
Ili Najaa Aimi Mohd Nordin ◽  
Muhammad Rusydi Muhammad Razif ◽  
Ahmad Athif Mohd Faudzi
Keyword(s):  
Fabrication Process ◽  
Maximum Pressure ◽  
Soft Robot ◽  
Soft Actuator ◽  
Simulation And Experiment ◽  
Mold Fabrication

Many researchers have been working on snake-like robots due to their flexibility, safety and dexterity. Traditional robots have rigid underlying structures that limit their ability to interact with their environment. In this work, soft robot is developed using three links of the flexible soft actuator connected by rubber joints. The actuators are fabricated using silicon Silastic P-1 where each actuator link consists of two semi-circular chambers and are reinforced with fibers. Fabrication process from CAD design, mold fabrication and validation with simulation and experiment is presented. The fabricated actuators can bend at 27.5o with maximum pressure of 180 kPa.

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