A novel mobile self-reconfigurable robot is presented. This robot consists of several independent units. Each unit is composed of modular components including ultrasonic sensor, camera, communication, computation, and...A novel mobile self-reconfigurable robot is presented. This robot consists of several independent units. Each unit is composed of modular components including ultrasonic sensor, camera, communication, computation, and mobility parts, and is capable of simple self-reconfiguring to enhance its mobility by expanding itself. Several units can not only link into a train or other shapes autonomously via camera and sensors to be a united whole robot for obstacle clearing, but also disjoin to be separate units under control after missions. To achieve small overall size, compact mechanical structures are adopted in modular components design, and a miniature advanced RISC machines （ARM） based embedded controller is developed for minimal power consumption and efficient global control. The docking experiment between two units has also been implemented.展开更多
The use of ultrasonic sensors has varied applications, but the sensor operation frequency limits the operating distance. An easy way to increase this distance is to couple a mechanical element （horn）, but it is nece...The use of ultrasonic sensors has varied applications, but the sensor operation frequency limits the operating distance. An easy way to increase this distance is to couple a mechanical element （horn）, but it is necessary to characterize this technique. In this paper the results obtained in a study of the behaviour of mechanical elements coupled to an ultrasonic sensor using finite element techniques are presented. These results have been obtained using Comsol Multiphysics modelling. Also, the effect caused by the sensor size on the radiation acoustic pressure has also been evaluated. In other way, in this paper it is presented the results obtained in the laboratory measurements. First, it is studied the influence of a straight horn attached to the ultrasonic sensor. Later, it is presented the variation in the sound pressure on the radiation axis when the sensor varies its size. In the final part of the paper, the experimental validation of the simulations is presented.展开更多
Metamaterials with higher-order topological band gaps that exhibit topological physics beyond the bulkedge correspondence provide unique application values due to their ability of integrating topological boundary stat...Metamaterials with higher-order topological band gaps that exhibit topological physics beyond the bulkedge correspondence provide unique application values due to their ability of integrating topological boundary states at multiple dimensions in a single chip.On the other hand,in the past decade,micromechanical metamaterials are developing rapidly for various applications such as micro-piezoelectricgenerators,intelligent micro-systems,on-chip sensing and self-powered micro-systems.To empower these cutting-edge applications with topological manipulations of elastic waves,higher-order topological mechanical systems working at high frequencies(MHz)with high quality-factors are demanded.The current realizations of higher-order topological mechanical systems,however,are still limited to systems with large scales(centimetres)and low frequencies(k Hz).Here,we report the first experimental realization of an on-chip micromechanical metamaterial as the higher-order topological insulator for elastic waves at MHz.The higher-order topological phononic band gap is induced by the band inversion at the Brillouin zone corner which is achieved by configuring the orientations of the elliptic pillars etched on the silicon chip.With consistent experiments,theory and simulations,we demonstrate the emergence of coexisting topological edge and corner states in a single silicon chip as induced by the higher-order band topology.The experimental realization of on-chip micromechanical metamaterials with higherorder topology opens a new regime for materials and applications based on topological elastic waves.展开更多
基金Supported by the National High Technology Research and Development Programme of China ( No. 2004AA420110)Heilongjiang Province Technology Foundation (No. GB04A502)
文摘A novel mobile self-reconfigurable robot is presented. This robot consists of several independent units. Each unit is composed of modular components including ultrasonic sensor, camera, communication, computation, and mobility parts, and is capable of simple self-reconfiguring to enhance its mobility by expanding itself. Several units can not only link into a train or other shapes autonomously via camera and sensors to be a united whole robot for obstacle clearing, but also disjoin to be separate units under control after missions. To achieve small overall size, compact mechanical structures are adopted in modular components design, and a miniature advanced RISC machines （ARM） based embedded controller is developed for minimal power consumption and efficient global control. The docking experiment between two units has also been implemented.
文摘The use of ultrasonic sensors has varied applications, but the sensor operation frequency limits the operating distance. An easy way to increase this distance is to couple a mechanical element （horn）, but it is necessary to characterize this technique. In this paper the results obtained in a study of the behaviour of mechanical elements coupled to an ultrasonic sensor using finite element techniques are presented. These results have been obtained using Comsol Multiphysics modelling. Also, the effect caused by the sensor size on the radiation acoustic pressure has also been evaluated. In other way, in this paper it is presented the results obtained in the laboratory measurements. First, it is studied the influence of a straight horn attached to the ultrasonic sensor. Later, it is presented the variation in the sound pressure on the radiation axis when the sensor varies its size. In the final part of the paper, the experimental validation of the simulations is presented.
基金supported by the Natural Science Foundation of Guangdong Province(2020A1515010549)China Postdoctoral Science Foundation(2020M672615 and 2019M662885)+1 种基金National Postdoctoral Program for Innovative Talents(BX20190122)the Jiangsu specially-appointed professor funding。
文摘Metamaterials with higher-order topological band gaps that exhibit topological physics beyond the bulkedge correspondence provide unique application values due to their ability of integrating topological boundary states at multiple dimensions in a single chip.On the other hand,in the past decade,micromechanical metamaterials are developing rapidly for various applications such as micro-piezoelectricgenerators,intelligent micro-systems,on-chip sensing and self-powered micro-systems.To empower these cutting-edge applications with topological manipulations of elastic waves,higher-order topological mechanical systems working at high frequencies(MHz)with high quality-factors are demanded.The current realizations of higher-order topological mechanical systems,however,are still limited to systems with large scales(centimetres)and low frequencies(k Hz).Here,we report the first experimental realization of an on-chip micromechanical metamaterial as the higher-order topological insulator for elastic waves at MHz.The higher-order topological phononic band gap is induced by the band inversion at the Brillouin zone corner which is achieved by configuring the orientations of the elliptic pillars etched on the silicon chip.With consistent experiments,theory and simulations,we demonstrate the emergence of coexisting topological edge and corner states in a single silicon chip as induced by the higher-order band topology.The experimental realization of on-chip micromechanical metamaterials with higherorder topology opens a new regime for materials and applications based on topological elastic waves.
