Self-Sensing Feedback Control of an Electrohydraulic Robotic Shoulder
The human shoulder with its glenohumeral joint, tendons, ligaments, and muscles allows for the execution of complex tasks with precision and efficiency. However, current robotic shoulder designs lack the compliance and compactness inherent in their biological counterparts. Various methods have been explored, including friction wheels, omni-wheels, gear-based mechanisms, and linear actuators, but each has its limitations. We propose a novel approach using antagonistically paired HASELs (hydraulically amplified self-healing electrostatic actuators).
Key features of our system
• Use of tendons for torque transmission, which minimizes frictional losses.
• Quick changes in movement while ensuring stable actuation at 3 Hz.
• A compliant design backed by soft artificial muscle actuators.
• Elimination of external sensors, thanks to the self-sensing capabilities of our actuators. This freedom ensures that the sensor integration cannot affect our compact joint design
• Our system can estimate the joint position as well as the end-effector position in the task space.