Load-Based Variable Transmission Mechanism for Robotic Applications

This paper presents a Load-Based Variable Transmission (LBVT) mechanism designed to enhance robotic actuation by dynamically adjusting the transmission ratio in response to external torque demands. Unlike existing variable transmission systems that require additional actuators for active control, the proposed LBVT mechanism leverages a pre-tensioned spring and four-bar linkage to passively modify the transmission ratio, thereby reducing the complexity of the robot joint actuation system. To evaluate the effectiveness of the LBVT mechanism, we conducted simulation-based analyses. The results confirm that the system achieves a 40% increase in transmission ratio upon reaching a predefined torque threshold, effectively amplifying joint torque when needed, without additional actuation. Furthermore, the simulations demonstrate a torque amplification effect, triggered when the applied force exceeds 18N, highlighting the system’s ability to autonomously respond to varying load conditions. This research contributes to the development of lightweight, efficient, and adaptive transmission systems for robotic applications, particularly in legged robots, where dynamic torque adaptation is crucial.