Dimension investigation to pneumatic network bending soft actuators for soft robotic applications

Author(s):  
Mohamed E. M. Salem ◽  
Qiang Wang

Abstract Soft actuators have been investigated for robots that interact with people, such as industrial robots, entertainment robots, and medical robots. Although soft actuators have been utilised in several applications, design tools that can assist in the effective and systematic design of actuators are needed. This paper focused on the most common soft actuators for bending motion, the Pneumatic Networks bending actuators. Paper presented a survey on the effects of changing the dimensions on the soft actuator and its cross-section shape on the soft actuator flexibility and the forces generated at different applied pressures. This survey can be used to optimize the dimension ratio for the soft actuator and the cross-section shape. Furthermore, this paper analyzed the possible reasons for the dimension change effect. The performance of the bending soft actuator was evaluated using ABAQUS/CAE software simulation models to provide quantitative insights into the actuators' behaviours. Thus, this paper provided a lot of insights that can be used to guide and accelerate the soft actuator design process to create strong and flexible Pneumatic Networks bending actuators. Using the paper insights outputs, a soft gripper was designed that can grasp many complex objects without needing any modification in the gripper shape. To show the proposed actuators' capacity to do complicated movements and expand their applications, a completely soft hand was created that can mimic the mobility of the human hand as nearly as possible, and this ability was verified using hand sign language settings.

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2119
Author(s):  
Luís Mesquita David ◽  
Rita Fernandes de Carvalho

Designing for exceedance events consists in designing a continuous route for overland flow to deal with flows exceeding the sewer system’s capacity and to mitigate flooding risk. A review is carried out here on flood safety/hazard criteria, which generally establish thresholds for the water depth and flood velocity, or a relationship between them. The effects of the cross-section shape, roughness and slope of streets in meeting the criteria are evaluated based on equations, graphical results and one case study. An expedited method for the verification of safety criteria based solely on flow is presented, saving efforts in detailing models and increasing confidence in the results from simplified models. The method is valid for 0.1 m2/s 0.5 m2/s. The results showed that a street with a 1.8% slope, 75 m1/3s−1 and a rectangular cross-section complies with the threshold 0.3 m2/s for twice the flow of a street with the same width but with a conventional cross-section shape. The flow will be four times greater for a 15% street slope. The results also highlighted that the flood flows can vary significantly along the streets depending on the sewers’ roughness and the flow transfers between the major and minor systems, such that the effort detailing a street’s cross-section must be balanced with all of the other sources of uncertainty.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rachel M. Starkweather ◽  
Svetlana V. Poroseva ◽  
David T. Hanson

AbstractAn important role that the leading-edge cross-section shape plays in the wing flight performance is well known in aeronautics. However, little is known about the shape of the leading-edge cross section of an insect’s wing and its contribution to remarkable qualities of insect flight. In this paper, we reveal, in the first time, the shape of the leading-edge cross section of a cicada’s wing and analyze its variability along the wing. We also identify and quantify similarities in characteristic dimensions of this shape in the wings of three different cicada species.


2019 ◽  
Vol 13 (1) ◽  
pp. 195-199 ◽  
Author(s):  
Alexandre Hubert ◽  
Jean-Philippe Colonna ◽  
Stéphane Bécu ◽  
Cécilia Dupré ◽  
Virginie Maffini-Alvaro ◽  
...  

2021 ◽  
Author(s):  
Teng Man ◽  
Herbert Huppert ◽  
Ling Li ◽  
Sergio Galindo-Torres

<p>The collapse of granular columns, which sheds light on the kinematics, dynamics, and deposition morphology of mass-driven flows, is crucial for understanding complex flows in both natural and engineering systems, such as debris flows and landslides. However, our research shows that a strong size effect and cross-section shape influence exist in this test. Thus, it is essential to better understand these effects. In this study, we explore the influence of both relative column sizes and cross-section shapes on the run-out behavior of collapsed granular columns and analyze their influence on the deposition morphology with the discrete element method (DEM) with Voronoi-based spheropolyhedron particles. We link the size effect that occurs in granular column collapse problems to the finite-size scaling functions and investigate the characteristic correlation length associated with the granular column collapses. The collapsing behavior of granular columns with different cross-section shapes is also studied, and we find that particles tend to accumulate in the direction normal to the edge of the cross-section instead of the vertex of it. The differences in the run-out behavior in different directions when the cross-section is no longer a circle can also be explained by the finite-size analysis we have performed in this study. We believe that such a study is crucial for us to better understand how granular material flows, how it deposits, and how to consider the size effect in the rheology of granular flows.</p>


2013 ◽  
Vol 405-408 ◽  
pp. 1292-1296 ◽  
Author(s):  
Hong Tao Xie

Taking portal segment in some shallow-buried tunnel in seismic region with strong motion as objects of study, the finite element analysis method was used to compare and assess the seismic behavior of the tunnel with different cross section shape. The results show that the linings displacement response of the tunnel with different cross section shape differs very minor under seismic load. Meanwhile there exists obvious difference in the lining internal forces of the tunnel with different cross section shape. Among all the tunnel with different section shape, the mechanics situation of the tunnel with triple arched sections is the best. While the section of the tunnel is closer to circular in shape, the mechanics situation of the lining can be effectively improved under seismic load.


2016 ◽  
Vol 29 (7) ◽  
pp. 849-856
Author(s):  
Tao Jiang ◽  
Chengzhen Geng ◽  
Hanmei Zhou ◽  
Ai Lu

Two kinds of glass fibers with round (RdGF) and rectangle cross-sections (RcGF) were used to reinforce polyphenylene sulfide (PPS), respectively. In this way, the effect of fiber cross-section shape on rheological and mechanical properties of the composites was studied for the first time. Results showed that the viscosity of the composites reinforced with RcGF was much lower than that of RdGF composites, owing to their higher sensitivity to flow. As a result, PPS/RcGF composites could be injection-molded at high fiber contents. Moreover, RcGF showed a better reinforcing effect on mechanical properties of PPS. So the use of RcGF could better balance the contradiction between processability and reinforcing effect for glass fiber-reinforced composites. Various characterizations were carried out to reveal the reinforcing mechanism. This work demonstrated the importance of fiber cross-section shape on design and production of fiber-reinforced composites.


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