Design of Soft Physiotherapy Actuator with Variable Stiffness Based on Particle Blocking

Aiming at the soft physiotherapy actuator carried at the end of the robotic arm in the physiotherapy robotic system, it is difficult to adjust the strength of physiotherapy due to the material stiffness limitation. Firstly, a variable stiffness soft physiotherapy actuator based on particle blocking was designed, and a pouring mold was made by 3D printing technology. Secondly, Yeoh constitutive model is used to predict the bending characteristics of the actuator, and the rationality of the model is verified by finite element simulation and experiment. Finally, the variable stiffness physiotherapy actuator was mounted on the end of the robot arm to form a physiotherapy robot system for verification. The experimental data show that under the same pressure, the design of variable stiffness can make the physiotherapy actuator bend <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$5^{\circ}-10^{\circ}$</tex> more. With the increase of bending angle, the application point of force shifts, which affects the intensity of physiotherapy.