Impedance for Assistance: Upper-Limb Assistive Soft Robotic Suit Using Linked-Layer Jamming Mechanisms

Area of Science:

• Robotics
• Biomechanics
• Materials Science

Background:

• Soft wearable robots offer comfort and ease of use.
• Balancing low impedance for comfort with sufficient assistive force is a key challenge.
• Existing designs often minimize impedance, potentially limiting assistive capabilities.

Purpose of the Study:

• To propose and validate an impedance-based assistance strategy for wearable robots.
• To exploit impedance variation in soft wearable robots to match human muscle contraction types.
• To reduce muscular load and enhance human motion assistance.

Main Methods:

• Development of a linked-layer jamming mechanism for variable impedance control.
• Integration of the mechanism into a wearable robot prototype for human multi-degree-of-freedom joints.
• Experimental validation of the impedance-based assistance approach.

Main Results:

• The linked-layer jamming mechanism demonstrated a broad variable range of impedance and directional torque.
• The wearable robot prototype effectively utilized impedance variation to assist human motion.
• Experimental results confirmed the effectiveness of the proposed impedance-based assistance strategy.

Conclusions:

• Suitably amplified impedance in wearable robots can beneficially assist human motion.
• This approach offers new possibilities for wearable robot design, enhancing task efficiency and reducing injury risk.
• Impedance, often minimized, can be a valuable design parameter when properly amplified.