Dynamics and isotropic control of parallel mechanisms for vibration isolation

Xiaolong Yang, Hongtao Wu, Yao Li, Shengzheng Kang, Bai Chen, Huimin Lu, Ka Man Lee, Ping Ji

Research output: Journal article publicationJournal articleAcademic researchpeer-review

39 Citations (Scopus)


Parallel mechanisms have been employed as architectures of high-precision vibration isolation systems. However, their performances in all degrees of freedom (DOFs) are nonidentical. The conventional solution to this problem is isotropic mechanism design, which is laborious and can hardly be achieved. This article proposes a novel concept; namely, isotropic control, to solve this problem. Dynamic equations of parallel mechanisms with base excitation are established and analyzed. An isotropic control framework is then synthesized in modal space. We derive an explicit relationship between modal control force and actuation force in joint space, enabling implementation of the isotropic controller. The multi-DOF system is transformed into multiidentical single-DOF systems. Under the framework of isotropic control, parallel mechanisms obtain an identical frequency response for all modes. An identical corner frequency, active damping, and rate of low-frequency transmissibility are achieved for all modes using a combining proportional, integral, and double integral compensator as a subcontroller. A 6-UPS parallel mechanism is presented as an example to demonstrate effectiveness of the new approach.

Original languageEnglish
Article number9099030
Pages (from-to)2027-2034
Number of pages8
JournalIEEE/ASME Transactions on Mechatronics
Issue number4
Publication statusPublished - Aug 2020


  • Dynamics
  • isotropic control
  • parallel mechanism
  • vibration isolation

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Computer Science Applications
  • Electrical and Electronic Engineering


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