The concept of morphing aircraft was developed many decades ago, and many researches on the morphing aircraft such as stability and control have been published. As the point of view of the dynamic theory, the dynamic system of the morphing aircraft is consisted with multiple subsystems, and each subsystem represents the morphing aircraft with specific structure to fulfill a particular flight task. The switching process from one structure to another for such a morphing aircraft is considered to be smooth and stable, and the switching time is also assumed to be infinitely small. In this paper, a morphing aircraft with high-speed structure, intermediate-structure and low-speed structure is studied. Such a morphing aircraft is set to switch between high-speed structure and low-speed structure when the speed of aircraft arrives a preset critical speed, and the analytical conditions for switchability is developed. If such a morphing aircraft cannot switch to a low-speed structure or high-speed structure at the moment when it arrives the critical speed, it will switch to an intermediate-structure and control to keep the speed remain constant. The analytical conditions for onset and vanish of such a morphing aircraft switching to the intermediate-structure are also provided. Mapping structure is defined to describe the periodic motions of such a morphing aircraft. The bifurcation scenario is calculated to show the complexity of such a hybrid dynamical system. A periodic motion is given to illustrate the flow of such a morphing aircraft switching on the velocity boundary.
{"title":"Discontinuous Dynamics and Bifurcation for Morphing Aircraft Switching on the Velocity Boundary","authors":"Jianzhe Huang, Xilin Fu, Zhongliang Jing, S. Xing","doi":"10.1115/detc2020-22008","DOIUrl":"https://doi.org/10.1115/detc2020-22008","url":null,"abstract":"\u0000 The concept of morphing aircraft was developed many decades ago, and many researches on the morphing aircraft such as stability and control have been published. As the point of view of the dynamic theory, the dynamic system of the morphing aircraft is consisted with multiple subsystems, and each subsystem represents the morphing aircraft with specific structure to fulfill a particular flight task. The switching process from one structure to another for such a morphing aircraft is considered to be smooth and stable, and the switching time is also assumed to be infinitely small. In this paper, a morphing aircraft with high-speed structure, intermediate-structure and low-speed structure is studied. Such a morphing aircraft is set to switch between high-speed structure and low-speed structure when the speed of aircraft arrives a preset critical speed, and the analytical conditions for switchability is developed. If such a morphing aircraft cannot switch to a low-speed structure or high-speed structure at the moment when it arrives the critical speed, it will switch to an intermediate-structure and control to keep the speed remain constant. The analytical conditions for onset and vanish of such a morphing aircraft switching to the intermediate-structure are also provided. Mapping structure is defined to describe the periodic motions of such a morphing aircraft. The bifurcation scenario is calculated to show the complexity of such a hybrid dynamical system. A periodic motion is given to illustrate the flow of such a morphing aircraft switching on the velocity boundary.","PeriodicalId":398186,"journal":{"name":"Volume 7: 32nd Conference on Mechanical Vibration and Noise (VIB)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127185994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, an impact based frequency up-conversion mechanism is studied using discontinuous dynamics theory. The mechanism consists of a sinusoidal vibrating plastic beam as a driving element and a piezoelectric bimorph as a generator. In order to remove the unfavorable stick motion and enhance the performance of the energy harvester, two pairs of racks and pinion gears and a slider-crank have been added to the system, which makes us able to control the impact occurring time between the driving beam and the generator. In this work, the Rayleigh-Ritz method was applied to obtain the distributed-parameter models of the driving beam and the piezoelectric generator. Both the forward and the backward mechanical-electrical coupling effects were considered during the modeling of the generator. The electrical and mechanical dynamic behaviors of the proposed piezoelectric energy harvester were analytically studied to better understand the effect of system parameters on the performance of piezoelectric energy harvester. Discontinuous dynamics theory was applied to obtain the generated power and voltage. The stability of the periodic solutions was obtained, and the bifurcation diagrams of displacements, impact velocities, generated power, and voltage were obtained analytically as the excitation frequency varying.
{"title":"Discontinuous Dynamics of a Frequency Up-Conversion Piezoelectric Harvester With an Impact Controlling Mechanism","authors":"S. Onsorynezhad, Fengxia Wang","doi":"10.1115/detc2019-97883","DOIUrl":"https://doi.org/10.1115/detc2019-97883","url":null,"abstract":"\u0000 In this study, an impact based frequency up-conversion mechanism is studied using discontinuous dynamics theory. The mechanism consists of a sinusoidal vibrating plastic beam as a driving element and a piezoelectric bimorph as a generator. In order to remove the unfavorable stick motion and enhance the performance of the energy harvester, two pairs of racks and pinion gears and a slider-crank have been added to the system, which makes us able to control the impact occurring time between the driving beam and the generator.\u0000 In this work, the Rayleigh-Ritz method was applied to obtain the distributed-parameter models of the driving beam and the piezoelectric generator. Both the forward and the backward mechanical-electrical coupling effects were considered during the modeling of the generator. The electrical and mechanical dynamic behaviors of the proposed piezoelectric energy harvester were analytically studied to better understand the effect of system parameters on the performance of piezoelectric energy harvester. Discontinuous dynamics theory was applied to obtain the generated power and voltage. The stability of the periodic solutions was obtained, and the bifurcation diagrams of displacements, impact velocities, generated power, and voltage were obtained analytically as the excitation frequency varying.","PeriodicalId":398186,"journal":{"name":"Volume 7: 32nd Conference on Mechanical Vibration and Noise (VIB)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125415385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：