The development of increasingly sophisticated sensors can facilitate the advancement of various technologies, including robots, security systems, virtual reality (VR) equipment and sophisticated prosthetics. Multimodal tactile sensors, which can pick up different types of touch-related information (e.g., pressure, texture and type of material), are among the most promising for applications that can benefit from the artificial replication of the human sense of touch.
While electronics engineers have created a wide range of highly sensitive tactile sensors over the past few decades, the accurate detection of both the direction and magnitude of applied forces has so far proven challenging. Moreover, many existing sensors are unable to correctly identify the materials that objects or surfaces are made of.
Researchers at the Chinese Academy of Sciences have recently developed a new multimodal tactile sensor inspired by human fingertips. The sensor, introduced in a paper published in Advanced Materials, was found to detect the direction of forces, while also accurately discerning among 12 materials commonly found in the real world.
“Multimodal tactile perception is crucial for advancing human–computer interaction, but real-time multidimensional force detection and material identification remain challenging,” wrote Chengcheng Han, Zhi Cao and their colleagues in their paper. Here, a finger-shaped tactile sensor (FTS) based on the triboelectric effect is proposed, capable of multidirectional force sensing and material identification.”
The new sensor is shaped like a human fingertip and is composed of two main complementary structures. The first is an external section designed to identify materials, while the second is an internal section that senses forces and their direction.
“Three materials are embedded into the surface of the silicone shell in the fingerpad, forming single-electrode sensors for material identification,” wrote Han, Cao and their colleagues.
“In the force-sensing section, the silicone shell’s outer surface is coated with conductive silver paste as a shielding layer. The inner wall has four silicone microneedle arrays and a silicone bump, while five silver electrodes are coated on the internal polylactic acid skeleton. The components connect via interlocking structures near the fingernail, allowing localized contact and separation between the silicone shell and skeleton, enabling force direction detection through signals from the five electrodes.”
The researchers evaluated their finger-shaped tactile sensor in a series of initial simulations and real-world experiments. They found that it performed well when applied to different forces, while also identifying different materials with a remarkably high accuracy.
As part of their real-world experiments, the researchers also integrated their sensor with a robotic hand, using the data analysis platforms LabVIEW and Jupyter to identify materials based on the data it picked up. Their findings were highly promising, suggesting that the sensor could be used to enhance the tactile capabilities of robotic systems.
“The outer sensors achieve 98.33% accuracy in recognizing 12 materials,” wrote the researchers. “Furthermore, integrated into a robotic hand, the FTS enables real-time material identification and force detection in an intelligent sorting environment. This research holds great potential for applications in tactile perception for intelligent robotics.”
The recent efforts by this research team could contribute to the future advancement of humanoid robots, smart prosthetics and other technologies that can benefit from the collection of touch-related data. In the future, the team’s sensor could also be improved further; for instance, to support the identification of an even wider range of materials and the detection of more types of tactile information.
Source: Tech Xplore / Digpu NewsTex