High Accuracy Stiffness Modeling Method for Hybrid Mechanism with Clearance and Redundant Drive

doi:10.3901/JME.2025.11.072

Abstract

Abstract: In response to the incomplete consideration of factors and the lack of a unified stiffness model in the existing stiffness models of hybrid mechanisms, this paper proposes a static stiffness modeling method for hybrid mechanisms that considers driving stiffness, rod deformation, redundant driving, and hinge clearance, and establishes a global static stiffness model. Firstly, a new configuration of a hybrid mechanism with high stiffness was proposed, and the constraint forces of each branch chain of the mechanism were derived. Considering the driving stiffness and rod deformation, based on the flexibility matrix superposition method, the overall stiffness matrix of the hybrid mechanism with ideal hinges is obtained. Then, a criterion for determining the offset of branch chains with hinge gaps is proposed. Based on the constraint force on each branch chain, the offset of branch chains with hinge clearances is analyzed. Based on the principle of virtual work, a mapping relationship between hinge clearances and the end deformation of the mechanism is established. The Monte Carlo method was used to solve the modeling error problem of hinge clearance offset caused by the coupling of branch chain constraints, and the stiffness distribution map of the mechanism's end effector was obtained. Finally, taking the 4CPR-PPP/2UPR-RR-2RPU+R hybrid mechanism with clearances as an example, the stiffness simulation of the mechanism was carried out through finite element analysis. The research results show that the high-precision stiffness modeling method proposed in this paper is correct, and it is of great significance for predicting the stiffness of the hybrid mechanism with clearances used in the heavy-duty field.

Key words: hybrid mechanism, stiffness, hinge clearance, compliance matrix, probabilistic statistical simulation

CLC Number:

TH112

WANG Sen, SONG Jingwei, LI Haoran, LI Shihua. High Accuracy Stiffness Modeling Method for Hybrid Mechanism with Clearance and Redundant Drive[J]. Journal of Mechanical Engineering, 2025, 61(11): 72-85.

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