• CN: 11-2187/TH
  • ISSN: 0577-6686

Journal of Mechanical Engineering ›› 2025, Vol. 61 ›› Issue (2): 130-140.doi: 10.3901/JME.2025.02.130

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Study on Force Control of Closed Chain Clamping in Pure Bending Experiment of Sheet Metal

HAN Fei, LI Yan   

  1. School of Mechanical and Material Engineering, North China University of Technology, Beijing 100144
  • Received:2024-01-21 Revised:2024-07-18 Published:2025-02-26

Abstract: The loading trajectory of the clamping end of sheet metal is uncertain when the pure bending moment is loaded. Based on the sheet bending testing equipment designed in the laboratory, from the point of displacement loading, based on impedance control theory, a method of tracking the internal force when the sheet metal deformation, in order to achieve the ideal pure bending force state of sheet metal only by pure bending moment. Firstly, analysis of the kinematic relationship of the testing machine mechanism and the closed-loop hybrid dynamics model of the sheet metal under force loading. After the internal forces of the plate are optimized and decoupling, the required control internal forces were obtained. Secondly, considering the vibration when loading the specimen under elastoplastic deformation, a fuzzy adaptive admittance controller based on dynamic model is designed to dynamically track the deformation internal force of the specimen. In the online force control experiment, compared with the MRAC adaptive force control method, the force error fluctuation range of the fuzzy variable admittance control method is reduced by 52.5%. Under the MRAC force control method and the fuzzy admittance force control method, the force control value range is reduced by 94% and 93.3%, respectively. The experiments demonstrate that the process control method, achieved by controlling the trajectory of the sheet metal clamping end, is effective in controlling the internal forces of the sheet metal. Moreover, a pure bending loading trajectory for thin galvanized iron test specimens has been obtained.

Key words: pure bending test, closed chain mixture, internal force tracking, admittance control

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