As critical components of aircraft skins and rocket fuel storage tank shells,large thin-walled workpieces are susceptible to vibration and deformation during machining due to their weak local stiffness.To address thes...As critical components of aircraft skins and rocket fuel storage tank shells,large thin-walled workpieces are susceptible to vibration and deformation during machining due to their weak local stiffness.To address these challenges,we propose a novel tunable electromagnetic semi-active dynamic vibration absorber(ESADVA),which integrates with a magnetic suction follower to form a followed ESADVA(follow-ESADVA)for mirror milling.This system combines a tunable magnet oscillator with a follower,enabling real-time vibration absorption and condition feedback throughout the milling process.Additionally,the device supports self-sensing and frequency adjustment by providing feedback to a linear actuator,which alters the distance between magnets.This resolves the traditional issue of being unable to directly monitor vibration at the machining point due to space constraints and tool interference.The frequency shift characteristics and vibration absorption performance are comprehensively investigated.Theoretical and experimental results demonstrate that the prototyped follow-ESADVA achieves frequency synchronization with the milling tool,resulting in a vibration suppression rate of approximately 47.57%.Moreover,the roughness of the machined surface decreases by18.95%,significantly enhancing the surface quality.The results of this work pave the way for higher-quality machined surfaces and a more stable mirror milling process.展开更多
Hard magnetic soft robots have been widely used in biomedical engineering.In these applications,it is crucial to sense the movement of soft robots and their interaction with target objects.Here,we propose a strategy t...Hard magnetic soft robots have been widely used in biomedical engineering.In these applications,it is crucial to sense the movement of soft robots and their interaction with target objects.Here,we propose a strategy to fabricate a self-sensing bilayer actuator by combining magnetic and ionic conductive hydrogels.The magnetic hydrogel containing NdFeB particles exhibits rapid response to magnetic field and achieve bending deformation.Meanwhile,the polyacrylamide(PAAm)hydrogel with lithium chloride(LiCl)allows for the sensing of deformation.The bending behavior of the bilayer under magnetic field is well captured by theoretical and simulated models.Additionally,the bilayer strain sensor shows good sensitivity,stability and can endure a wide-range cyclic stretching(0-300%).These merits qualify the self-sensing actuator to monitor the motion signals,such as bending of fingers and grasping process of an intelligent gripper.When subject to an external magnetic field,the gripper can grab a cube and sense the resistance change simultaneously to detect the object size.This work may provide a versatile strategy to integrate actuating and self-sensing ability in soft robots.展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.12172248,12021002,12302022,and 12132010)the Tianjin Research Program of Application Foundation and Advanced Technology of China(No.22JCQNJC00780)IoT Standards and Application Key Laboratory of the Ministry of Industry and Information Technology of China(No.202306)。
文摘As critical components of aircraft skins and rocket fuel storage tank shells,large thin-walled workpieces are susceptible to vibration and deformation during machining due to their weak local stiffness.To address these challenges,we propose a novel tunable electromagnetic semi-active dynamic vibration absorber(ESADVA),which integrates with a magnetic suction follower to form a followed ESADVA(follow-ESADVA)for mirror milling.This system combines a tunable magnet oscillator with a follower,enabling real-time vibration absorption and condition feedback throughout the milling process.Additionally,the device supports self-sensing and frequency adjustment by providing feedback to a linear actuator,which alters the distance between magnets.This resolves the traditional issue of being unable to directly monitor vibration at the machining point due to space constraints and tool interference.The frequency shift characteristics and vibration absorption performance are comprehensively investigated.Theoretical and experimental results demonstrate that the prototyped follow-ESADVA achieves frequency synchronization with the milling tool,resulting in a vibration suppression rate of approximately 47.57%.Moreover,the roughness of the machined surface decreases by18.95%,significantly enhancing the surface quality.The results of this work pave the way for higher-quality machined surfaces and a more stable mirror milling process.
基金support from the National Natural Science Foundation of China(No.12172272 and 11820101001).
文摘Hard magnetic soft robots have been widely used in biomedical engineering.In these applications,it is crucial to sense the movement of soft robots and their interaction with target objects.Here,we propose a strategy to fabricate a self-sensing bilayer actuator by combining magnetic and ionic conductive hydrogels.The magnetic hydrogel containing NdFeB particles exhibits rapid response to magnetic field and achieve bending deformation.Meanwhile,the polyacrylamide(PAAm)hydrogel with lithium chloride(LiCl)allows for the sensing of deformation.The bending behavior of the bilayer under magnetic field is well captured by theoretical and simulated models.Additionally,the bilayer strain sensor shows good sensitivity,stability and can endure a wide-range cyclic stretching(0-300%).These merits qualify the self-sensing actuator to monitor the motion signals,such as bending of fingers and grasping process of an intelligent gripper.When subject to an external magnetic field,the gripper can grab a cube and sense the resistance change simultaneously to detect the object size.This work may provide a versatile strategy to integrate actuating and self-sensing ability in soft robots.
