scholarly journals Hydraulically Coupled Dielectric Elastomer Actuators for a Bioinspired Suction Cup

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3481
Author(s):  
Chi Zhang ◽  
Lei Liu ◽  
Kanghui Xu ◽  
Zhonghong Dong ◽  
Yuxi Ding ◽  
...  
Keyword(s):  
Stretch Ratio ◽  
Dielectric Elastomer ◽  
Compact Structure ◽  
Suction Force ◽  
Dc Voltage ◽  
Suction Cup ◽  
Dielectric Elastomer Actuators ◽  
Acrylic Plate ◽  
Suction Cups ◽  
Chamber Angle

Suction cups of cephalopods show a preeminent performance when absorbing irregular or flat objects. In this paper, an octopi-inspired suction cup, driven by hydraulically coupled dielectric elastomer actuators (HCDEAs), is proposed, which is considered to be controlled easily and have compact structure. To investigate the performance of suction cups, experiments have been conducted to clarify the effect of the pre-stretch ratio and chamber angle on suction forces. It could be seen that both factors have a complicated influence on suction forces, and the best performance obtained was a reasonable combination of the pre-stretch ratio and chamber angle. Here, we achieved a maximum suction force of 175 mN with λp = 1.2, α = 23° under a DC voltage of 3500 V. To enhance the capacity and adaptation of the suction cup, flat objects of various types of materials were introduced as targets. Experimental results displayed that for tested materials, including a dry/wet acrylic plate, CD, ceramic wafer, and aluminum plate, the suction cup showed outstanding performance of absorbing and lifting the target without any damage or scratch to them. Our research may serve as a guide to the optimal design and provide insights into the performance of the HCDEAs-actuated suction cup.

scholarly journals Soft Hybrid Suction Cup Capable of Sticking to Various Objects and Environments

Actuators ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 50
Author(s):  
Hideyuki Tsukagoshi ◽  
Yuichi Osada
Keyword(s):  
Vertical Direction ◽  
Check Valve ◽  
Adhesive Force ◽  
Outer Diameter ◽  
Shear Direction ◽  
Concrete Walls ◽  
Suction Force ◽  
Suction Cup ◽  
Valve Function ◽  
Suction Cups

A universal suction cup that can stick to various objects expands the areas in which robots can work. However, the size, shape, and surface roughness of objects to which conventional suction cups can stick are limited. To overcome this challenge, we propose a new hybrid suction cup structure that uses the adhesive force of sticky gel and the suction force of negative pressure. In addition, a flexible and thin pneumatic balloon actuator with a check valve function is installed in the interior, enabling the controllable detachment from objects. The prototype has an outer diameter of 55 mm, a weight of 18.8 g, and generates an adsorption force of 80 N in the vertical direction and 60 N in the shear direction on porous walls where conventional suction cups struggle to adsorb. We confirmed that parts smaller than the suction cup and fragile potato chips are adsorbed by the prototype. Finally, the effectiveness of the proposed method is verified through experiments in which a drone with the prototypes can be attached to and detached from concrete walls and ceilings while flying; the possibility of adsorption to dusty and wet plates is discussed.

scholarly journals Analysis of the Pneumatic System Parameters of the Suction Cup Integrated with the Head for Harvesting Strawberry Fruit

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4389
Author(s):  
Sławomir Kurpaska ◽  
Zygmunt Sobol ◽  
Norbert Pedryc ◽  
Tomasz Hebda ◽  
Piotr Nawara
Keyword(s):  
Testing Machine ◽  
Equivalent Diameter ◽  
Strawberry Fruit ◽  
Measurement Instruments ◽  
Suction Force ◽  
Practical Applications ◽  
Surface Areas ◽  
Suction Cup ◽  
Suction Cups ◽  
End Effectors

Fruit and vegetable harvest efficiency depends on the mechanization and automation of production. The available literature lacks the results of research on the applicability of pneumatic end effectors among grippers for the robotic harvesting of strawberries. To determine their practical applications, a series of tests was performed. They included the determination of the morphological indicators of the strawberry, fruit suction force, the real stress exerted by fruit suckers and the degree of fruit damage. The fruits’ morphological indicators included the relationships between the weight and geometrical dimensions of the tested fruit, the equivalent diameter, and the sphericity coefficient. The fruit suction force was determined on a stand equipped with a vacuum pump, and control and measurement instruments, as well as a MTS 2 testing machine. The necrosis caused by tissue damage to the fruits by suction cup adhesion was assessed by counting the necrosis surface areas using the LabView programme. The assessment of the necrosis was conducted immediately upon the test’s performance, after 24 and after 72h. The stress values were calculated by referring the values of the suction forces obtained to the surface of the suction cup face. The tests were carried out with three constructions of suction cups and three positions of suction cup faces on the fruits’ surface. The research shows that there is a possibility for using pneumatic suction cups in robotic picking heads. The experiments performed indicate that the types of suction cups constructions, and the zones and directions of the suction cups’ application to the fruit significantly affect the values of the suction forces and stresses affecting the fruit. The surface areas of the necrosis formed depend mainly on the time that elapses between the test and their assessment. The weight of strawberry fruit in the conducted experiment constituted from 13.6% to 23.1% of the average suction force.

A Self-Sealing Suction Cup Array for Grasping

2011 ◽  
Vol 3 (4) ◽  
Author(s):  
Chad C. Kessens ◽  
Jaydev P. Desai
Keyword(s):  
Large Range ◽  
Tensile Loading ◽  
Physical Contact ◽  
Element Analysis ◽  
Suction Force ◽  
Suction Cup ◽  
Wide Range ◽  
Suction Cups ◽  
The Cost

While suction technology was invented long ago, the application of suction to object manipulation thus far has been confined to many small, well-defined problem sets. Its potential for grasping a large range of unknown objects remains relatively unexplored. This paper introduces the design of a suction cup that is “self-sealing.” The suction cups comprising the grasper exert no suction force when the cup(s) are not in contact with an object, but instead exert suction force only when they are in physical contact with an object. Since grasping is achieved purely by passive means, the cost and weight associated with individual sensors, valves, and/or actuators are essentially eliminated. This paper presents the design, analysis, fabrication, and experimental results of an array of such self-sealing suction cups. Finite element analysis of the cup is shown for both compressive and tensile loading, and the quality of the internal seal is quantified. Finally, performance is shown to be comparable to that of a commercially available cup, and grasping capability is demonstrated on a wide range of objects.

scholarly journals Bio-inspired Miniature Suction Cups Actuated by Shape Memory Alloy

10.5772/7228 ◽  
2009 ◽  
Vol 6 (3) ◽  
pp. 29 ◽  
Author(s):  
Hu Bing-Shan ◽  
Wang Li-Wen ◽  
Fu Zhuang ◽  
Zhao Yan-zheng
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Analytical Model ◽  
Basic Structure ◽  
Thin Elastic Plate ◽  
Climbing Robots ◽  
Suction Cup ◽  
Sma Actuator ◽  
Suction Cups ◽  
Pressure Suction

Wall climbing robots using negative pressure suction always employ air pumps which have great noise and large volume. Two prototypes of bio-inspired miniature suction cup actuated by shape memory alloy (SMA) are designed based on studying characteristics of biologic suction apparatuses, and the suction cups in this paper can be used as adhesion mechanisms for miniature wall climbing robots without air pumps. The first prototype with a two-way shape memory effect (TWSME) extension TiNi spring imitates the piston structure of the stalked sucker; the second one actuated by a one way SMA actuator with a bias has a basic structure of stiff margin, guiding element, leader and elastic element. Analytical model of the second prototype is founded considering the constitutive model of the SMA actuator, the deflection of the thin elastic plate under compound load and the thermo-dynamic model of the sealed air cavity. Experiments are done to test their suction characteristics, and the analytical model of the second prototype is simulated on Matlab/simulink platform and validated by experiments.

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