Manufacture and Deformation Angle Control of a Two-Direction Soft Actuator Integrated with SMAs

Area of Science:

• Robotics
• Materials Science
• Control Systems

Background:

• Soft actuators offer compliant and adaptable robotic solutions.
• Integrating shape memory alloys (SMAs) provides actuation capabilities.
• Precise control of SMA-based actuators is challenging due to nonlinearities and hysteresis.

Purpose of the Study:

• To develop and characterize a 3D-printed soft actuator with integrated SMA wires.
• To model, simulate, and control the bidirectional bending motion of the actuator.
• To address the control challenges posed by SMA nonlinearities.

Main Methods:

• 3D printing of a thermoplastic polyurethane (TPU) matrix.
• Integration of SMA wires encased in Polytetrafluoroethylene (PTFE) tubes.
• Implementation of a computer vision system for deformation measurement.
• System identification for mathematical modeling and simulation.
• Design and experimental validation of a proportional-integral (PI) controller.

Main Results:

• Successful fabrication of a 3D-printed soft actuator capable of bidirectional bending.
• Development of a dynamic model based on experimental data.
• Demonstration of effective control using a PI controller to manage deformation angles.
• Validation of the controller's performance through real-time experiments.

Conclusions:

• The developed 3D-printed soft actuator with SMA wires shows promise for robotic applications.
• The implemented control strategy effectively addresses the challenges of SMA actuation.
• This work contributes to the advancement of controllable soft robotic systems.