by Researchers have made a groundbreaking discovery in the field of flexible sensors, paving the way for enhanced sensing capabilities in various applications. Despite the advancements in flexible sensors over the past decade, accurately measuring complex deformations resulting from multi-axial forces or strains has been a significant challenge due to the lack of independent perception of multi-axial stimuli.
The main hindrance to independent perception of biaxial stimuli has been identified as the Poisson’s effect of sensing materials. Researchers have found that materials with a zero Poisson’s ratio (ZPR), which maintain a constant transverse width under longitudinal strain, may offer a solution to the interference issues in perceiving biaxial or multi-axial stimuli.
Professor Hao Wu and Dr. Xin Huang from Huazhong University of Science and Technology led a study that explored the development of zero Poisson’s ratio elastomer membranes. By combining traditional positive Poisson’s ratio (PPR) structure with negative Poisson’s ratio (NPR) structure, the researchers devised a method to achieve a zero Poisson’s ratio structure.
Through finite element analysis, the team determined that the Poisson’s ratio of the hybrid structure was a superposition of the Poisson’s ratio of individual structures. By adjusting the feature size and width of the hybrid structure, the Poisson’s ratio could be varied between positive and negative values, leading to the optimal parameters for obtaining the ZPR membrane. The ZPR membrane exhibited a significantly lower Poisson’s ratio compared to membranes without the hybrid structure, showcasing the effectiveness of the new design.
The flexible sensors based on the ZPR membranes demonstrated the ability to accurately detect uniaxial stimuli and independently detect biaxial stimuli. When subjected to uniaxial stretching, the electric resistance of sensing units along the stretching direction showed a linear increase, while the resistance of units perpendicular to the stretching direction exhibited minimal change. This unique feature allowed the sensors to respond only to the tensile strain in the corresponding axis, enabling independent detection of biaxial stimuli.
The ZPR flexible sensors offer accurate detection of force, strain, and motion status in scenarios involving robotic manipulation and locomotion with complex deformation. These sensors can precisely measure contact forces between rigid manipulators and grasped objects, irrespective of the deformation of the objects. Additionally, the sensors can detect the normal bending of fingers and unexpected collisions with obstacles when attached to manipulators, as well as determine the locomotion distance and direction of biaxial soft robots.
With their exotic sensing capabilities, ZPR sensors hold immense potential for applications in healthcare, human-machine interfaces, and robotic tactile sensing, marking a significant advancement in the field of flexible sensor technology.
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1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it
