Journal of Advanced Mechanical Design, Systems, and Manufacturing (Sep 2021)

Evaluation of torque-dependent coupling characteristics and their influence on the system vibration characteristics

  • Massimiliano RIGACCI,
  • Ryuta SATO,
  • Keiichi SHIRASE,
  • Taichi SASAKI

DOI
https://doi.org/10.1299/jamdsm.2021jamdsm0060
Journal volume & issue
Vol. 15, no. 5
pp. JAMDSM0060 – JAMDSM0060

Abstract

Read online

Coupling characteristics that depend on the applied torque and the influence of this torque dependency on the system response are investigated in this study. A dedicated apparatus, consisting of two servomotors connected by a coupling, was specifically designed for this purpose. To measure the frequency response of the apparatus, a sweep signal with a frequency between 100 Hz and 2000 Hz was imposed as a torque command of the motor through a servo analyzer. To evaluate the coupling characteristics, such as torsional stiffness and damping, from the frequency response, the apparatus was modeled as a two-degrees-of-freedom system. The characteristics were identified, based on the resonance frequency and the vibration amplitude at the frequency. The relationship between the coupling characteristics and the coupling working time was investigated by conducting dedicated experiments after every 30 min of working time for 3.5 h. The relation between the torque magnitude and the coupling frequency response was also investigated by imposing several torque settings on the sweep signal. It was found that both the working time and the sweep magnitude significantly affected the coupling characteristics. Finally, the velocity step-response test was simulated, based on the identified coupling stiffness and damping, and the results were compared with the experimental acquisitions with various feedback-gain settings. The response oscillated under a higher gain setting. The torque dependency of the coupling characteristics was implemented in the model, based on the evaluated results. It was confirmed that the velocity step response can be accurately simulated by the model, when the torque dependency of the coupling characteristics is considered. In other words, the torque dependency of the coupling characteristics plays an important role in the vibration characteristics of the system.

Keywords