Electromechanical Control and Stability Analysis of a Soft Swim-Bladder Robot Driven by Dielectric Elastomer

2017 ◽  
Vol 84 (9) ◽  
Author(s):  
Bangyuan Liu ◽  
Feiyu Chen ◽  
Sukai Wang ◽  
Zhiqiang Fu ◽  
Tingyu Cheng ◽  
...  

Compared to the conventional rigid robots, the soft robots driven by soft active materials possess unique advantages with their high adaptability in field exploration and seamless interaction with human. As one type of soft robot, soft aquatic robots play important roles in the application of ocean exploration and engineering. However, the soft robots still face grand challenges, such as high mobility, environmental tolerance, and accurate control. Here, we design a soft robot with a fully integrated onboard system including power and wireless communication. Without any motor, dielectric elastomer (DE) membrane with a balloonlike shape in the soft robot can deform with large actuation, changing the total volume and buoyant force of the robot. With the help of pressure sensor, the robot can move to and stabilize at a designated depth by a closed-loop control. The performance of the robot has been investigated both experimentally and theoretically. Numerical results from the analysis agree well with the results from the experiments. The mechanisms of actuation and control may guide the further design of soft robot and smart devices.

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Toshio Takayama ◽  
Yusuke Sumi

AbstractRecently pneumatic-driven soft robots have been widely developed. Usually, the operating principle of this robot is the inflation and deflation of elastic inflatable chambers by air pressure. Some soft robots need rapid and periodic inflation and deflation of their air chambers to generate continuous motion such as progress motion or rotational motion. However, if the soft robot needs to operate far from the air pressure source, long air tubes are required to supply air pressure to its air chambers. As a result, there is a large delay in supplying air pressure to the air chamber, and the motion of the robot slows down. In this paper, we propose a compact device that changes its airflow passages by self-excited motion generated by a supply of continuous airflow. The diameter and the length of the device are 20 and 50 mm, respectively, and can be driven in a small pipe. Our proposed in-pipe mobile robot is connected to the device and can move in a small pipe by dragging the device into it. To apply the device widely to other soft robots, we also discuss a method of adjusting the output pressure and motion frequency.


Author(s):  
bicheng Chen ◽  
Nianfeng Wang ◽  
Haozheng Chen ◽  
Xianmin Zhang

Micromachines ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 485 ◽  
Author(s):  
Gianni Stano ◽  
Luca Arleo ◽  
Gianluca Percoco

Air tightness is a challenging task for 3D-printed components, especially for fused filament fabrication (FFF), due to inherent issues, related to the layer-by-layer fabrication method. On the other hand, the capability of 3D print airtight cavities with complex shapes is very attractive for several emerging research fields, such as soft robotics. The present paper proposes a repeatable methodology to 3D print airtight soft actuators with embedded air connectors. The FFF process has been optimized to manufacture monolithic bending PneuNets (MBPs), an emerging class of soft robots. FFF has several advantages in soft robot fabrication: (i) it is a fully automated process which does not require manual tasks as for molding, (ii) it is one of the most ubiquitous and inexpensive (FFF 3D printers costs < $200) 3D-printing technologies, and (iii) more materials can be used in the same printing cycle which allows embedding of several elements in the soft robot body. Using commercial soft filaments and a dual-extruder 3D printer, at first, a novel air connector which can be easily embedded in each soft robot, made via FFF technology with a single printing cycle, has been fabricated and tested. This new embedded air connector (EAC) prevents air leaks at the interface between pneumatic pipe and soft robot and replaces the commercial air connections, often origin of leakages in soft robots. A subsequent experimental study using four different shapes of MBPs, each equipped with EAC, showed the way in which different design configurations can affect bending performance. By focusing on the best performing shape, among the tested ones, the authors studied the relationship between bending performance and air tightness, proving how the Design for Additive Manufacturing approach is essential for advanced applications involving FFF. In particular, the relationship between chamber wall thickness and printing parameters has been analyzed, the thickness of the walls has been studied from 1.6 to 1 mm while maintaining air tightness and improving the bending angle by 76.7% under a pressure of 4 bar. It emerged that the main printing parameter affecting chamber wall air tightness is the line width that, in conjunction with the wall thickness, can ensure air tightness of the soft actuator body.


2019 ◽  
Vol 28 (10) ◽  
pp. 103002 ◽  
Author(s):  
Ujjaval Gupta ◽  
Lei Qin ◽  
Yuzhe Wang ◽  
Hareesh Godaba ◽  
Jian Zhu

2020 ◽  
Vol 10 (2) ◽  
pp. 640 ◽  
Author(s):  
Jung-Hwan Youn ◽  
Seung Mo Jeong ◽  
Geonwoo Hwang ◽  
Hyunwoo Kim ◽  
Kyujin Hyeon ◽  
...  

This paper reviews state-of-the-art dielectric elastomer actuators (DEAs) and their future perspectives as soft actuators which have recently been considered as a key power generation component for soft robots. This paper begins with the introduction of the working principle of the dielectric elastomer actuators. Because the operation of DEA includes the physics of both mechanical viscoelastic properties and dielectric characteristics, we describe theoretical modeling methods for the DEA before introducing applications. In addition, the design of artificial muscles based on DEA is also introduced. This paper reviews four popular subjects for the application of DEA: soft robot hand, locomotion robots, wearable devices, and tunable optical components. Other potential applications and challenging issues are described in the conclusion.


Author(s):  
Jonathan S. Terry ◽  
Justin Whitaker ◽  
Randal W. Beard ◽  
Marc D. Killpack

Abstract The compliance and other nonlinear dynamics of large-scale soft robots makes effective control difficult. This is especially true when working with unknown payloads or when the system dynamics change over time which is likely to happen for soft robots. In this paper, we present a novel method of coupling model reference adaptive control (MRAC) with model predictive control (MPC) for platforms with antagonistic pneumatic actuators. We demonstrate its utility on a fully inflatable, six degree-of-freedom pneumatically actuated soft robot manipulator that is over two meters long. Specifically, we compare control performance with no integral controller, with an integral controller, and with MRAC when running a nominal model predictive controller with significant weight attached to the end effector.


2016 ◽  
Vol 10 (4) ◽  
pp. 494-502 ◽  
Author(s):  
Mohamed Najib Ribuan ◽  
◽  
Shuichi Wakimoto ◽  
Koichi Suzumori ◽  
Takefumi Kanda ◽  
...  

This manuscript explains the employment of flexible actuators to act as a soft robot and transporting agent to assist medical X-ray examinations. Although soft robots from silicone material can be transparence and a human compliance used as medical assistive devices, soft robots have some problems: they tend to be sluggish, have long and imprecise gait trajectories, and need their control parameters to be adjusted for motion diversion. A soft robot with omnidirectional locomotion has been created, one that has a combination of pneumatic rubber legs that form a soft robot platform and an associated hardware setup. Tests have confirmed its omnidirectional locomotion ability; it has a maximum speed of 6.90 mm/s in forward locomotion and a maximum payload of 70 g. These features indicate that the robot can be used as a medical assistive device for fluoroscopy examinations.


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