Position and Force Control of a Soft Pneumatic Actuator

Area of Science:

• Robotics
• Mechanical Engineering
• Control Systems

Background:

• Soft robots offer safer alternatives to rigid robots in sensitive fields like aerospace and medicine.
• Soft pneumatic actuators (SPAs) are inspired by nature and provide compliant movement.
• Controlling the precise motion and force of SPAs is crucial for their practical application.

Purpose of the Study:

• To develop and validate a control strategy for a soft pneumatic actuator capable of reshaping in the x-y plane.
• To model the dynamic behavior of the SPA using system identification techniques.
• To compensate for system hysteresis and improve trajectory tracking accuracy.

Main Methods:

• System identification was employed to model the SPA's behavior and simulate its time response.
• A cascaded control strategy was designed for robot control.
• The Prandtl-Ishlinskii (P-I) model and its inverse were utilized to measure, simulate, and compensate for system hysteresis.

Main Results:

• The developed control architecture was simulated and experimentally implemented on a laboratory setup.
• The system demonstrated improved precision in tracking control after hysteresis compensation.
• Experimental results validated the effectiveness of the proposed control strategy for the soft actuator.

Conclusions:

• The study successfully demonstrated a robust control method for a 2D soft pneumatic actuator.
• Hysteresis compensation using the inverse P-I method significantly enhanced the precision of the soft robot's end-point control.
• The findings pave the way for more accurate and reliable soft robotic systems in various industries.