TESCLA: A Fully Soft Electromagnetic Linear Actuator With Continuous Bending Enabled by Liquid-Metal Solenoids

Area of Science:

• Robotics
• Materials Science
• Electromagnetism

Background:

• Linear actuators are crucial for robots and wearables, but existing soft actuators have limited range and discrete bending.
• Current soft linear actuators restrict workspace and achievable curvatures.

Purpose of the Study:

• To propose a novel tubular electromagnetic soft conformal linear actuator (TESCLA).
• To achieve large actuation strokes and continuous bending in soft linear actuators.
• To enable conformal deformation to surrounding environments.

Main Methods:

• Developed a TESCLA using liquid-metal solenoids (soft stator) and compliant magnetic composites (soft mover).
• Employed a synchronous actuation strategy for controllable bidirectional electromagnetic thrust.
• Utilized inductance variance measurement for step position estimation.
• Evaluated actuator design via numerical simulations for performance optimization.

Main Results:

• The TESCLA demonstrates large actuation strokes and continuous bending capabilities.
• Bidirectional electromagnetic thrust is controllable via electric current.
• Inductance variance accurately estimates step position.
• Simulations optimized design for thrust force, minimum step size, and sensing resolution.

Conclusions:

• The TESCLA overcomes limitations of existing soft linear actuators, offering enhanced range and flexibility.
• The actuator's design and functionality were validated through simulations and demonstrations.
• Potential applications include biomimetic robotics and wearable haptic devices.