Achieving high-quality and large-stroke constant torque by axial force release
Bai, Ruiyu Yang, Nan Qiu, Zhiwei Johnson, Shane Wu, Ke Li, Bo Chen, Guimin
Bai, Ruiyu
Yang, Nan
Qiu, Zhiwei
Johnson, Shane
Wu, Ke
Li, Bo
Chen, Guimin
Supervisor
Department
Robotics
Embargo End Date
Type
Journal article
Date
2025
License
Language
English
Collections
Research Projects
Organizational Units
Journal Issue
Abstract
Compliant constant-torque mechanisms (CCTMs) maintain constant-torque without the need for complex closed-loop feedback systems, broadening their applications in rehabilitation devices, surgical tools, and cooperative robotic arms. However, CCTMs present considerable design challenges due to the pronounced nonlinearities that arise due to large deflections and multi-axial loadings. Traditional CCTM design strategies focus on managing post-buckling phenomena, often leading to increased stresses and an imbalance in positive and negative stiffness, compromising torque consistency and stroke capacity. This study introduces a novel CCTM that effectively decouples the multi-axial loadings and releases axial forces, isolating beam bending forces. This decoupling is achieved by incorporating a parallel-guided compliant mechanism at the fixed end of the beam, which reduces stress and enhances torque stability throughout the operational range. Through the partical swarm optimization of geometric design parameters using the chained beam constraint model, this research has produced a CCTM capable of maintaining torque fluctuations below 0.39% over a rotational range of 18° to 68°. Experimental validations confirm the design’s superiority in providing an extended constant torque stroke and improved consistency, distinguishing it from conventional straight-beam CCTMs.
Citation
R. Bai et al., “Achieving high-quality and large-stroke constant torque by axial force release,” Mechanism and machine theory, vol. 205, pp. 105869-, 2025, doi: 10.1016/j.mechmachtheory.2024.105869
Source
Mechanism and Machine Theory
Conference
Keywords
Compliant mechanisms, Compliant constant torque mechanisms, Beam flexures, Load-stiffening effect, Chained beam constraint model
Subjects
Source
Publisher
Elsevier