1. Compact Visuo-tactile Robotic Skin for Micron-level Tactile Perception

Visuo-tactile skin (VTS) is categorized into coating type, marking type, and thermochromic type. The wear resistance and spatial resolution of the coating are the core issues for the coating type VTS. Recently, Professor Fang Bin from Beijing University of Posts and Telecommunications, in collaboration with Professor Yang Yiyong from China University of Geosciences (Beijing), published a paper titled "A Compact Visuo-tactile Robotic Skin for Micron-level Tactile Perception" in the Q1 journal IEEE Sensors Journal. Building upon the gilding process, they proposed a surface reinforcement treatment for the coating surface, effectively enhancing the durability of the thin coating.

Main contributions: 1) For the first time, surface reinforcement treatment (drawing process) was applied to the skin coating to enhance its wear resistance. Compared to sprayed coatings, drawn coatings exhibit higher robustness. 2) Silver/aluminum foil can be transformed into nanoscale particles, enabling the coating to exhibit macroscopic continuity, enhancing the coating's ductility and robustness. Additionally, the high fineness allows the drawn coating to achieve micron-level spatial resolution.

Advertisement

The sensor is divided into three modules: contact module, imaging module, and mechanical module.

1) Contact module: It includes an elastomer, coating, and acrylic board. The elastomer is attached to the acrylic board. To prevent the contact module from detaching from the main body, grooves and a cover are used to secure the elastomer and acrylic board.

2) Imaging module: It consists of an illumination sub-module and a camera sub-module. Considering the narrow space of the robotic skin, a flexible LED strip is used to meet adaptive bending. The strip surrounds the acrylic board and elastomer. The imaging module employs a smaller-sized mini camera module: 8.5 mm × 8.5 mm × 4.95 mm. It also features automatic exposure control balance and a minimum imaging distance of 15 mm.

3) Mechanical module: It includes support structures and mechanical accessories. The camera base, skin base, and brackets are integrated into the casing to encapsulate the contact module and imaging module.

Experimental part: A) The performance of the coating was analyzed through microstructure analysis of the coating; B) Spatial resolution was tested; C) The mechanical properties and robustness of the skin and coating were tested; D) The learnability of tactile information was discussed; E) The work was compared with other visuo-tactile sensors in terms of coating performance.Experiment A: In this study, the microstructures of spray coatings, foil coatings, and wire-drawing coatings were observed using an electron microscope. The wire-drawing aluminum foil/silver foil has a nanoscale particle distribution, and its structure is closer to that of spray coatings.

Experiment B: Due to the difficulty in quantitatively measuring spatial resolution, it is common to use test objects with different detail scales to press against a tactile sensor, and the visualization of tactile details is judged to determine the spatial resolution. In this work, three types of test objects were used: tweezers (millimeter scale), fingerprints (sub-millimeter scale), and banknote patterns (micrometer scale). The wire-drawing coating can clearly display the patterns of banknotes, achieving a spatial resolution at the micrometer level.

The tactile characteristics visualization of foil coatings and wire-drawing coatings for objects with different detail scales. Spatial resolution can be divided into millimeter scale (greater than 1 millimeter), sub-millimeter scale (between 0.1 millimeters and 1 millimeter), and micrometer scale (less than 0.1 millimeters). The unbroken foil coating can clearly present tactile details. Large particles and damaged surfaces affect the continuity of tactile feature visualization, such as wire-drawing copper foil. Wire-drawing silver/aluminum foil has a nanoscale particle distribution, presenting a continuous coating surface in the image. The wire-drawing coating can capture details at the micrometer level, similar to metal sputtering and spray coatings.

Experiment C: Through pressing tests, it was verified that wire-drawing coatings (silver and aluminum) have high robustness and can adapt to varying degrees of pressing. This is helpful for large-scale tactile data collection and data quality.

Figure 5 Pressing test. The wire-drawing coating can adapt to contact with sharp objects.

Figure 6 Wear resistance test. The wire-drawing coating has higher wear resistance than the spray coating.

Experiment D: In this work, 18 different textured fabrics were selected as test subjects. The recognition of fabric categories and attributes was achieved through a multi-task learning network.

Figure 7 Texture images of different fabrics.

Experiment E: By comparing with representative visual-tactile sensors, it can be concluded that wire-drawing coatings and spray coatings are thin, have high spatial resolution, and significantly improve the wear resistance of thin coatings.Summary: This work introduces a new type of coating, namely the drawing coating. It enhances the wear resistance of thin coatings while maintaining high sensitivity and micrometer-level spatial resolution. These rich tactile characteristics can be learned through artificial feature extraction or deep learning and used to establish a mapping relationship between tactile information and object attributes. The new process provides a new approach for robust imaging of tactile sensors.

2. Over half a year, five rounds of hundred-million-yuan-level financing have been completed! Volant Air completes hundreds of millions of yuan in Series A++++ financing.

Recently, Volant Air has successfully completed hundreds of millions of yuan in Series A++++ financing. This round of financing was led by the Beijing Robotics Industry Fund, with participation from Jing Guorui Fund, Shougang Fund's equity investment platform Shoucheng Capital, and Yan Chuang Group. Geng Xin Capital served as the financial advisor for this round of financing. To date, the company has successfully completed a cumulative financing of 100 million USD in the A1 round and has simultaneously initiated the next round of financing. As the fifth hundred-million-yuan-level financing obtained by Volant since 2024, this round will be used to accelerate the development and manufacturing of the VE25 model, the certification of the VE25-100, and the commercialization of high-grade commercial passenger eVTOL, on the basis of continuous promotion of the VE25 prototype flight and testing.

Established in 2023, the Beijing Robotics Industry Development Investment Fund has a total scale of 10 billion yuan, jointly managed by Jing Guorui Fund and Shougang Fund's equity investment platform Shoucheng Capital. This investment in Volant Air is also a cautious and significant layout by Jing Guorui Fund and Shoucheng Capital in the direction of intelligent mobile logistics.

In the just concluded A1 round of financing, 15 well-known institutions including Dinghui Baifute, Huaqiang Capital, Qifu Capital, Junlian Capital, Beijing Robotics Industry Fund, Jing Guorui Fund, Shoucheng Capital, Jingkai Capital, Nanshan Zhanxin Investment, Dunhong Assets, Beijing Daxing Industry Development Guidance Fund, Yan Chuang Group, Qingsong Fund, Mingshi Capital, and Weiguang Venture Capital have successively invested or continued to invest, with a total investment amount of 100 million USD. The company's financial advisor, Geng Xin Capital, has deeply cultivated the industry and provided close services, creating a new paradigm for financing efficiency and financing models in China's low-altitude economy. Volant Air will officially initiate the next round of financing, with Hua Xin Capital joining and serving as the financial advisor in subsequent financing. Hua Xin Capital is firmly optimistic about Volant, "Volant has a top aviation expert team, systematic product development capabilities, rich certification experience, leading commercial progress, continuous financing capabilities, and a mature ecosystem, making it the first choice for Hua Xin's layout in the low-altitude economy eVTOL."

Source: VOLANT Volant Air