Motion-dependent modal analysis of flexible-joint mechanisms

IF 4.9 2区工程技术 Q1 ACOUSTICS

Journal of Sound and Vibration Pub Date : 2025-08-28 DOI:10.1016/j.jsv.2025.119416

Jianning Yang, Fan Meng, Xiao Wang, Hanwen Song

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引用次数: 0

Abstract

Conventional modal analysis of flexible-joint mechanisms often overlooks motion-induced inertial and Coriolis effects. These effects inherently render the system non-self-adjoint, resulting in dynamic characteristics that differ from those of stationary states. To address this, motion-dependent modal analysis is proposed for flexible-joint mechanisms, where modal parameters are parameterized instantaneously by the states of rigid-body motion. First, a generalized dynamic equation of 2n dimensions is formulated, which incorporates both motor dynamics and feedforward-feedback control. Then, the vibration model is derived through Taylor expansion around arbitrary dynamic equilibrium states. Based on this motion-dependent vibration model with time-varying matrices, state space formulations are developed to define instantaneous modal parameters under arbitrary motion conditions. Subsequently, the influence of rigid-body motion on the vibrational characteristics is analyzed and verified with a 2-DOF mechanism. Finally, the model is applied to calculate the instantaneous modal parameters of a 6-DOF mechanism, verifying that the effect of rigid–flexible coupling is non-negligible under high-speed motion. The results show that the first-order frequency of the system can be reduced by 15.4% under high-speed motion, and Coriolis effects may induce instantaneous negative damping.

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柔性关节机构运动相关模态分析

传统的柔性关节机构模态分析往往忽略了运动引起的惯性效应和科里奥利效应。这些影响固有地使系统非自伴随，导致动态特性不同于那些静止状态。为了解决这个问题，针对柔性关节机构提出了运动相关的模态分析，其中模态参数由刚体运动状态瞬时参数化。首先，建立了一个包含电机动力学和前馈反馈控制的2n维广义动力学方程。然后，通过围绕任意动态平衡状态的泰勒展开，推导出振动模型。在此运动相关时变矩阵振动模型的基础上，建立了定义任意运动条件下瞬时模态参数的状态空间表达式。随后，分析了刚体运动对该机构振动特性的影响，并用二自由度机构进行了验证。最后，将该模型应用于某六自由度机构的瞬时模态参数计算，验证了高速运动下刚柔耦合的影响是不可忽略的。结果表明，在高速运动下，系统的一阶频率可降低15.4%，科里奥利效应可引起瞬时负阻尼。

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来源期刊

Journal of Sound and Vibration 工程技术-工程：机械

CiteScore

9.10

自引率

10.60%

发文量

551

审稿时长

69 days

期刊介绍： The Journal of Sound and Vibration (JSV) is an independent journal devoted to the prompt publication of original papers, both theoretical and experimental, that provide new information on any aspect of sound or vibration. There is an emphasis on fundamental work that has potential for practical application. JSV was founded and operates on the premise that the subject of sound and vibration requires a journal that publishes papers of a high technical standard across the various subdisciplines, thus facilitating awareness of techniques and discoveries in one area that may be applicable in others.