Approximately one-third of fresh fruits are lost in the supply chain, with half the losses occurring during in-field harvesting and in-plant grading. The complexity of supply chain, waste and economic losses could be reduced through integrated non-destructive harvesting and in-field quality grading. Here we developed a self-decoupled tactile sensor for robotic soft gripper, embedding three-axis self-decoupled triboelectric soft tactile sensors across fingers. During single harvesting operation, the strategy can measure the gripping force, fruit firmness, weight by tactile sensors. Hence, integrated non-destructive harvesting and in-field quality grading can be achieved. Tactile sensors are bioinspired by the deformation mechanics of octopus suckers under normal and tangential forces. It features dual-mode TENG, integrating vertical contact-separation and horizontal sliding modes. This structure can independently respond to normal and tangential forces. It will generate a superimposed triboelectric signal with three spatially decoupled components. Consequently, the three-axis force can be easily decoupled with three triboelectric signals independently, achieving high-precision measurement within the 0-20 N range. Finally, we demonstrate the practical efficacy of the sensing strategy through in-field experiments. During grasping, fruit firmness is evaluated from the normal force response over time. Upon fruit detachment, tactile sensors monitor both normal and tangential forces in real-time to prevent damage. Finally, with the gripper reoriented palm-down, the fruit weight is non-destructively calculated via static equilibrium between the tangential force and the fruit's gravity. We develop a robotic sensing system for integrated, non-destructive fruit harvesting and in-field grading, thereby streamlining the supply chain, reducing waste, and enhancing food safety.

Chemical functional groups on solid surfaces greatly influence contact electrification (CE) at water–solid interfaces. Previous studies of their effects mainly swapped materials or bonded related molecules to a substrate, introducing other factors of influence. This work aims at unambiguously demonstrating the role of functional groups in water-polymer CE. We study the contribution of functional groups, by using ion coupled plasma etching to modify a high-density polyethylene (HDPE) film, a polymer with a naturally quasi-null charge transfer ability. Fluoride (HDPE–F) and hydroxyl (HDPE–OH) functional groups are generated and endowed HDPE with charge withdrawing ability. HDPE–F withdraws 2.5–2.7 times more charges than HDPE–OH. Concurrently, the surface charges accumulated generate electrostatic forces, altering the droplets motion. This phenomenon provides another approach to study CE, helping to evaluate the contribution of electrons to solid–liquid CE. Finally, employing HDPE–F to perform contact-electro-catalysis shows its activity is 2.4 times higher than that of commercial fluorinated films.

As extremely important physiological indicators, respiratory signals can often reflect or predict the depth and urgency of various diseases. However, designing a wearable respiratory monitoring system with convenience, excellent durability, and high precision is still an urgent challenge. Here, we designed an easy-fabricate, lightweight, and badge reel-like retractable self-powered sensor (RSPS) with high precision, sensitivity, and durability for continuous detection of important indicators such as respiratory rate, apnea, and respiratory ventilation. By using three groups of interdigital electrode structures with phase differences, combined with flexible printed circuit boards (FPCBs) processing technology, a miniature rotating thin-film triboelectric nanogenerator (RTF-TENG) was developed. Based on discrete sensing technology, the RSPS has a sensing resolution of 0.13 mm, sensitivity of 7 P·mm⁻¹, and durability more than 1 million stretching cycles, with low hysteresis and excellent anti-environmental interference ability. Additionally, to demonstrate its wearability, real-time, and convenience of respiratory monitoring, a multifunctional wearable respiratory monitoring system (MWRMS) was designed. The MWRMS demonstrated in this study is expected to provide a new and practical strategy and technology for daily human respiratory monitoring and clinical diagnosis.