Robotic ankle structure using a pair of elastic actuators in parallel

Three-point support robotic ankle structure with parallel-arranged SEA pair

This technology implements a closed-chain mechanism that utilizes a pair of parallel-arranged Series Elastic Actuators (SEA) for roll and pitch control of a robotic ankle, forming a three-point support structure with the shank.

Conventional single-actuator ankle structures suffer from limited load-bearing capacity, low impact resistance, and structural constraints that hinder stable gait on diverse terrains.

This technology connects the parallel SEAs and the shank using a first upper coupling and a second lower coupling (a combination of universal joints) to form a closed-chain, three-point support structure, enabling roll and pitch rotation of the foot through independent actuator operation.

‍

‍

Key Features:

• A robotic foot with a rectangular cross-section and a pair of SEAs arranged in parallel above the foot.
• A shank that connects to the SEA pair at individual points to form a three-point support structure and provides support for the SEAs.
• A first coupling consisting of two universal joints that connects the support axes of the SEA pair to the top of the shank support axis.
• A second coupling consisting of three universal joints that connects through the robotic foot to link the SEA support axes and the bottom of the shank support axis.

‍