Stiffness modeling of a 2-DoF over-constrained planar parallel mechanism. (July 2023)

• Record Type: Journal Article
• Authors: Görgülü, Ibrahimcan; Dede, Mehmet Ismet Can; Kiper, Gökhan
• Is Part Of: Mechanism and machine theory. Volume 185(2023)
• Publication Date: 2023-07
• Subjects: Virtual joint method -- Over-constrained structure -- Industrial robots -- Stiffness modeling -- Time-efficient computation; Machine theory -- Periodicals; Machinery -- Periodicals; Machines -- Périodiques; Génie mécanique -- Périodiques; Machine theory; Machinery; Periodicals; 621.81
• DOI: 10.1016/j.mechmachtheory.2023.105343
• Languages: English
• ISSNs: 0094-114X

Abstract

Abstract: Stiffness model acquisition of over-constrained parallel mechanisms is relatively difficult since they have more than necessary kinematic loops. In this study, a stiffness modeling solution for over-constrained parallel mechanisms is proposed while considering the computational cost efficiency. Three contributions of the paper are: (1) Presenting the stiffness modeling procedure for serially connected closed-loop structures by using the Virtual Joint Method (2) Considering the effect of dynamic auxiliary forces and dynamic external forces on the mobile platform's deflection and achieving a direct solution by using superposition principle (3) A model fitting procedure for modifying the stiffness coefficients to comply with the experimental data. A 2 degrees-of-freedom over-constrained parallel mechanism is investigated as a case study. However, the proposed stiffness model is 6-DoF since compliant deflections occur in any direction. A finite element analysis and an experimental study verify the model's results. Highlights: Stiffness modeling of over-constrained parallel mechanisms with consecutive closed loops. Auxiliary load contribution to the compliant deflection computation via superposition method. Stiffness model modification matrix to comply with the uncertainties and experimental results.