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Research on High Precision Stiffness Modeling Method of Redundant Over-Constrained Parallel Mechanism
Sen Wang1,2, Haoran Li1,2, Xueyan Han1,2
1Parallel Robot and Mechatronic System Laboratory of Hebei Province, Yanshan University, Qinhuangdao 066004, China.
Sensors (Basel, Switzerland)
|July 14, 2023
Summary
This study introduces a novel global stiffness model for parallel mechanisms (PMs) accounting for joint clearance and deformation. The method enhances stiffness evaluation for complex robotic systems.
Area of Science:
- Robotics
- Mechanical Engineering
- Computational Mechanics
Background:
- Existing stiffness modeling methods for parallel mechanisms (PMs) are fragmented and lack a unified, global approach.
- These methods often fail to comprehensively account for factors like joint clearance and deformation, limiting accuracy.
Purpose of the Study:
- To develop a unified, global static stiffness modeling method for redundant, over-constrained parallel mechanisms (PMs) that incorporates joint clearance and deformation.
- To provide a high-precision method for evaluating the stiffness performance of complex PMs.
Main Methods:
- Utilized screw theory, strain energy, and the virtual work principle to establish the global stiffness model.
- Incorporated driving stiffness, branch deformation, redundant driving, joint clearance, and joint contact deformation into the model.
- Employed a probability statistical model to address uncertainties in joint offset and contact area due to coupled branch constraint forces.
- Validated the method through finite element analysis (FEA) on a 2UPR-RR-2RPU redundant PM.
Main Results:
- Successfully developed a global stiffness matrix for the ideal joint mechanism using strain energy and Castigliano's second theorem.
- Established mathematical relationships between joint clearance, contact deformation, and end-effector deformation.
- Quantified the uncertainty associated with joint clearance and contact deformation under coupled forces.
- FEA simulations confirmed the accuracy and effectiveness of the proposed high-precision stiffness modeling method.
Conclusions:
- The proposed stiffness modeling method offers a comprehensive and unified approach for redundant, over-constrained parallel mechanisms.
- This method accurately evaluates the stiffness performance of PMs, addressing limitations of traditional approaches.
- The study provides a valuable tool for the design and analysis of high-precision robotic systems.
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