摘要
水下电液作动器(EHA)因高集成度和低泄漏风险而逐渐成为替代传统水下液压系统的理想方案。然而,其紧凑结构加剧了激振源与振动传递路径的耦合,同时水下EHA通常在变转速工况下运行,使振动特性分析更加复杂。针对此,围绕水下EHA的振动传递机制与动态特性展开系统性研究,重点关注其在变转速条件下的时变振动行为。构建柱塞泵流体激励模型,通过仿真与实验揭示其激振机制及幅频特征;基于频响函数分析识别系统主导固有频率,并结合实验揭示振动传递的频率相关性;最后,综合运用时频分析与阶次分析方法,对变转速工况下水下EHA的非平稳振动信号进行解析,揭示其动态频谱演化过程以及激振源与结构间的耦合传递机制。结果表明:柱塞泵的7 N倍转频激励是主要激振源;485、750、1870 Hz的固有频率在高转速下易与激振源低阶次谐波叠加,导致共振并显著加剧振动;采用时频分析与阶次分析相结合的方法,提取了变转速工况下非平稳振动信号中的结构共振及时变激振频率成分。分析结果与激振源模型及频响函数分析结果相符,验证了该方法的有效性,为水下EHA振动建模、振动评估及结构优化提供了理论依据。
Underwater electro-hydraulic actuator(EHA)has emerged as a promising alternative to conventional underwater hydraulic systems due to their high integration and low leakage risk.However,their compact structure intensifies the coupling between excitation sources and vibration transmission paths.Additionally,underwater EHA often operate under variable rotational speed conditions,complicating the analysis of their vibration characteristics.In view of this,the vibration transmission mechanisms and dynamic characteristics of underwater EHA were investigated systematically,with a particular focus on their time-varying vibration behavior under variable rotational speed conditions.A fluid excitation model of the piston pump was developed,and its excitation mechanisms and amplitude-frequency characteristics were revealed through both simulation and experimental methods.Then,the dominant natural frequencies of the EHA were identified using frequency response function analysis,and the frequency-dependent nature of vibration transmission was clarified experimentally.Finally,a hybrid method combining time-frequency analysis and order analysis was employed to analyze non-stationary vibration signals under variable speed conditions,revealing the dynamic evolution of the frequency spectrum and the coupling transmission mechanism between the excitation source and the structure.The results indicate that the 7th-order harmonic excitation of the piston pump,corresponding to seven times the shaft speed,serves as the primary source of excitation.The natural frequencies at 485 Hz,750 Hz and 1870 Hz are prone to superimpose with the low-order harmonics of the excitation source at high rotational speeds,leading to resonance and significantly exacerbating vibration.By combining time-frequency analysis with order analysis,structural resonance and time-varying excitation frequency components in non-stationary vibration signals under variable speed conditions were extracted.The analysis results are consistent with the excitation source model and frequency response function analysis results,verifying the effectiveness of this method.It provides a methodology for vibration modeling,performance evaluation and structural optimization of underwater EHA.
作者
苏伟鸿
童心
刘轩硕
杨朝坤
刘佳佳
聂勇
梅德庆
陈正
SU Weihong;TONG Xin;LIU Xuanshuo;YANG Chaokun;LIU Jiajia;NIE Yong;MEI Deqing;CHEN Zheng(State Key Laboratory of Ocean Sensing,Zhejiang University,Hangzhou Zhejiang 310000,China;Ocean College,Zhejiang University,Zhoushan Zhejiang 316021,China;State Key Laboratory of Fluid Power&Mechatronic Systems,Zhejiang University,Hangzhou Zhejiang 310000,China)
出处
《机床与液压》
北大核心
2025年第23期17-24,共8页
Machine Tool & Hydraulics
基金
国家重点研发计划(2023YFC2809903)。
关键词
电液作动器
振动传递机制
动态特性
变转速
柱塞泵
electro-hydraulic actuator
vibration transmission mechanisms
dynamic characteristics
variable rotational speed
piston pump
