scholarly journals Self-Excited Air Flow Passage Changing Device for Periodic Pressurization of Soft Robot

2021 ◽  
Author(s):  
Toshio Takayama ◽  
Yusuke Sumi
Keyword(s):  
Mobile Robot ◽  
Rotational Motion ◽  
Air Pressure ◽  
Soft Robot ◽  
Pressure Source ◽  
Large Delay ◽  
Soft Robots ◽  
Flow Passage ◽  
Output Pressure ◽  
Air Chamber

Abstract Recently 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 slow 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.

scholarly journals Self-excited air flow passage changing device for periodic pressurization of soft robot

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Toshio Takayama ◽  
Yusuke Sumi
Keyword(s):  
Mobile Robot ◽  
Rotational Motion ◽  
Air Pressure ◽  
Soft Robot ◽  
Pressure Source ◽  
Large Delay ◽  
Soft Robots ◽  
Flow Passage ◽  
Output Pressure ◽  
Air Chamber

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.

Scale and Configuration Effects of an Airchamber on PTO of Oscillating Water Column Type Wave Energy Converters

2021 ◽  
Author(s):  
Tomoki Ikoma ◽  
Shota Hirai ◽  
Yasuhiro Aida ◽  
Koichi Masuda
Keyword(s):  
Water Column ◽  
Wave Energy ◽  
Water Surface ◽  
Air Pressure ◽  
Scale Model ◽  
Linear Potential ◽  
Oscillating Water Column ◽  
Wave Energy Converters ◽  
Air Chamber ◽  
Energy Converters

Abstract Wave energy converters (WECs) have been extensively researched. The behaviour of the oscillating water column (OWC) in OWC WECs is extremely complex due to the interaction of waves, air, and turbines. Several problems must be overcome before such WECs can be put to practical use. One problem is that the effect of the difference in scale between a small-scale experimental model and a full-scale model is unclear. In this study, several OWC models with different scales and geometries were used in forced oscillation tests. The wave tank was 7.0 m wide, 24.0 m long, and 1.0 m deep. In the static water experiment, we measured the air pressure and water surface fluctuations in an air chamber. For the experiments, models with a box shape with an open bottom, a manifold shape with an open bottom, and a box shape with a front opening, respectively, were fabricated. Furthermore, 1/1, 1/2, and 1/4 scale models were fabricated for each shape to investigate the effects of scale and shape on the air chamber characteristics. Numerical calculations were carried out by applying linear potential theory and the results were compared with the experimental values. The results confirmed that the air chamber shape and scale affect the air pressure fluctuation and water surface fluctuation inside the OWC system.

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 Additive Manufacturing for Soft Robotics: Design and Fabrication of Airtight, Monolithic Bending PneuNets with Embedded Air Connectors

Micromachines ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 485 ◽  
Author(s):  
Gianni Stano ◽  
Luca Arleo ◽  
Gianluca Percoco
Keyword(s):  
Additive Manufacturing ◽  
Wall Thickness ◽  
Chamber Wall ◽  
Soft Robotics ◽  
Soft Robot ◽  
Soft Robots ◽  
Bending Performance ◽  
3D Print ◽  
Air Tightness ◽  
The Relationship

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.

Improvement of Wave Power Take-Off Performance due to the Projecting Walls for OWC Type WEC

2013 ◽  
Author(s):  
Tomoki Ikoma ◽  
Koichi Masuda ◽  
Hikaru Omori ◽  
Hiroyuki Osawa ◽  
Hisaaki Maeda
Keyword(s):  
Prediction Method ◽  
Air Pressure ◽  
Wave Power ◽  
Linear Potential ◽  
Oscillating Water Column ◽  
Air Chamber ◽  
Pressure Water ◽  
Linear Potential Theory ◽  
Hydrodynamic Behaviors ◽  
Water Elevation

This paper describes a method in order to improve the performance of the primary conversion of wave power take-off. A corresponding wave energy convertor (WEC) is an oscillating water column (OWC) type. The method of the improvement has been proposed and its usefulness has been confirmed in past researches. In the method, projecting walls were attached onto front of inlet-outlet of OWC. The prediction method of hydrodynamic behaviors for the projecting walls installed OWC type WEC is explained in the paper. The boundary element method with the Green’s function is applied and influence of air pressure and free surface within every an air-chamber was directly taken into consideration in the prediction method based on a linear potential theory. Validity of the prediction method was proved comparing with results of model experiments. Series calculations are performed with the prediction method. Behaviors of air pressure, water elevation and the efficiency of primary conversion of wave power are investigated. From the calculations, length of the projecting walls was shown to affect the efficiency of primary conversion. It was available to equip the projecting walls for the improvement in oblique waves to beam sea condition as well as head sea condition. As well as only the projecting walls, application and effects of the end walls with the slit were investigated in the paper. The end walls were very useful to improve the efficiency.

Interrelation Between Fluid Particles Rotational Motion in Rotating Flow Passage of Centrifugal Pump and Overall Efficiency

Volume 3 ◽  
2004 ◽  
Author(s):  
Takaharu Tanaka ◽  
Chao Liu
Keyword(s):  
Centrifugal Pump ◽  
Rotational Motion ◽  
Rotating Flow ◽  
Energy Losses ◽  
Trailing Edge ◽  
Flow Passage ◽  
Impeller Outlet ◽  
Overall Efficiency ◽  
Fluid Particles ◽  
The Way

Main purpose of investigation has been put on the hydraulic energy losses caused in the rotating flow passage of centrifugal pump. Result of discussion shows that fundamental poor efficiency is brought by the fluid particles poor rotational motion at the trailing edge of impeller outlet, including the rotational motion caused in the flow passage between impeller blades rather than the hydraulic energy losses caused in the rotating flow passage. Therefore, our main purpose of investigation has to be put on the way rather to the fluid particles rotational motion caused at the trailing edge of impeller outlet and that caused between impeller blades.

A LABORATORY MESOCOSM AS A TOOL TO STUDY PAH DEGRADATION IN A COASTAL MARSH WETLAND

2014 ◽  
Vol 2014 (1) ◽  
pp. 400-407
Author(s):  
Doorce S. Batubara ◽  
Donald D. Adrian ◽  
Martin S. Miles ◽  
Ronald F. Malone
Keyword(s):  
High Tide ◽  
Air Pressure ◽  
Coastal Marsh ◽  
Wetland Soil ◽  
Phenanthrene Degradation ◽  
Pah Degradation ◽  
Tidal Water ◽  
Air Chamber ◽  
Marsh Wetland ◽  
Intertidal Wetland

ABSTRACT Polycyclic aromatic hydrocarbons (PAHs) are one of the contaminants of concern in coastal marsh environments which are subject to crude oil spills. A laboratory scale mesocosm can be used to complement field study of PAH degradation in coastal marshes. Coastal marsh wetland features, such as its soil, tidal cycles, and flushing, that may play roles in PAH degradation can be simulated in a laboratory mesocosm. The laboratory mesocosm tank is made of acrylic as the main construction material with an air chamber inside the tank which functions as a pneumatic system and tidal water storage compartment. Two trays filled with contaminated marsh wetland soil are situated at two different levels: the lower one is constantly submerged while the higher one is intermittently drained. When the air pressure inside the air chamber is high, the water will flow out from the air chamber to the tank to create high tide. When the air pressure inside the air chamber is low, the water will flow back from the tank to the air chamber to create low tide inside the tank. The tidal water sits in the air chamber until the next high air pressure. The cycles of air pressure inside the tank are controlled by an electrical air pump connected to a timer. The experimental setup can consist of several replicates with an air chamber inside each replicate is controlled by a master pneumatic tank. The model PAH contaminant used in the experiment was phenanthrene, a three-benzene-ring PAH, which was spiked to the wetland soil. The experimental results show that the phenanthrene degradation in the intertidal wetland soil is higher than that of in the subtidal wetland soil presumably due to the availability of oxygen in the intertidal wetland soil. The laboratory mesocosm developed in this study can be used as a tool for examining PAH degradation and other non-volatile organic contaminants.

An Investigation on Real and Imaginary Energy Transfer Mechanism Caused in Rotating Flow Passage of Centrifugal Pump

2005 ◽  
Author(s):  
Takaharu Tanaka ◽  
Chao Liu
Keyword(s):  
Energy Transfer ◽  
Physical Properties ◽  
Centrifugal Pump ◽  
Rotational Motion ◽  
Rotating Flow ◽  
Physical Parameters ◽  
Energy Transfer Mechanism ◽  
Flow Passage ◽  
Different Types ◽  
Force Velocity

Hydraulic energy is constructed from real and imaginary energies. Their acting directions are normal to each other. Their physical properties are quite different. All the physical parameters, such as force, velocity, and acceleration therefore consist of two different type real and imaginary functions. Physically, there are three different types of fluid particles rotational motion: straightly forward non-rotational motion, which is based upon kinetic real physical parameters, circularly forward rotational motion, which is based upon un-kinetic imaginary physical parameters, and their combined rotational motion. Their interrelation is shown in diagram.

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