In context
In 2024, variable-stiffness actuators were a key research focus for safe human-robot interaction and adaptable automation. However, most lever-based designs suffered from stiffness-deflection coupling, complicating control and limiting practical use in industrial settings.
What was reported
Researchers proposed a lever-type variable-stiffness joint with an adjustable pivot to eliminate this coupling. Through static analysis, they proved that joint stiffness is independent of deflection angle when the pivot is positioned correctly.
To adjust the pivot smoothly, they designed an involute cam mechanism, which provides a linear relationship between cam rotation and pivot position. This linearity simplifies stiffness adjustment, making the system easier to control.
A prototype was built and tested. Simulations and experiments confirmed the variable-stiffness principle and verified that stiffness and deflection angle are decoupled, matching the theoretical model.
Why it mattered
This design offers a practical solution for robots requiring precise stiffness control without complex compensation algorithms. It could improve safety and adaptability in collaborative robots and advanced manufacturing systems, where variable stiffness is essential for handling diverse tasks.
"The feasibility of the variable-stiffness principle and the decoupling between stiffness and deflection angle are verified."
Source: 《机器人》期刊 (robot.sia.cn) · Published 2024-09-15 · “基于渐开线轮廓凸轮的杠杆式偏角解耦变刚度关节设计”