A Variable Stiffness Actuator Module With Favorable Mass Distribution for a Bio-inspired Biped Robot

Area of Science:

• Robotics
• Biomechanics
• Mechanical Engineering

Background:

• Humanoid robots require advanced actuators like variable stiffness actuators (VSAs) for human-like locomotion.
• VSAs, with two motors for stiffness and position control, add mass and complexity to humanoid designs.
• Leg mass distribution significantly impacts a humanoid's energy efficiency (cost of transport).

Purpose of the Study:

• To present a novel VSA module for the bio-inspired humanoid robot Binocchio.
• To improve mass distribution in humanoid robots by relocating actuator components.
• To enable more efficient and human-like locomotion in multi-degree-of-freedom joints.

Main Methods:

• Designed a novel VSA module with all components on one side of the actuated joint.
• Integrated the VSA module into the multi-degree-of-freedom joints of the Binocchio humanoid robot.
• Conducted experiments to validate static characteristics (torque, stiffness) and dynamic responses.

Main Results:

• The VSA module was successfully designed and integrated into the Binocchio robot.
• Static tests confirmed accurate estimation of output torque and stiffness.
• Dynamic response experiments demonstrated the system's capabilities.
• The VSA system effectively replicated human-like kinematic, torque, and stiffness profiles.

Conclusions:

• The novel VSA design offers a favorable mass distribution for humanoids.
• This VSA facilitates integration into centralized multi-degree-of-freedom joints.
• The system enables human-like locomotion by controlling torque and stiffness profiles effectively.