A self-sensing intelligent soft pneumatic actuator with soft magnetic structures

Many achievements for soft pneumatic actuators (SPAs) are made in the structure design and application demonstration. However, few studies focus on their mechanical sensing which is significant toward autonomous and intelligent soft robots. Herein, a self-sensing intelligent soft pneumatic actuator (SISPA) is developed by integrating a sensing layer that is silicone rubber/NdFeB composite twined with a varnished wire. The induced voltage is generated with the bending deformation of the sensing layer. Experimental results show that the induced voltage rises with the increasing mass fraction of magnetic powders, turns of the varnished wire, and thicknesses and widths of the composite. The bending deformation of the SISPA is also investigated experimentally and numerically. The bending angle of the SISPA reaches 225.5° with an applied pressure of 40 kPa, which is 92.68% of that of the SPA without embedding the sensing layer. The effect of the four parameters of the sensing layer on the bending deformation is investigated as well. In conclusion, the sensing layer has a slight effect on the bending deformation of the SISPA. Based on the experimental data, we find that there is a linear relationship between the bending angle and magnetic flux change. So the relation of the bending deformation and output voltage is formulated approximatively. Finally, an intelligent bionic hand is developed by utilizing the SISPA, which outputs different signals according to diverse gestures. Therefore, the proposed SISPA can be an attractive candidate involving accuracy control and intelligent soft robots.