Analysis and control of soft electropneumatic gripper fabricated by additive manufacturing method

Flexible electropneumatic grippers contribute significantly to the development of soft robotic devices and enable different and complex hardware designs for soft robots. Besides the many advantages, the lack of position feedback of flexible grippers poses a problem for position control. This thesis study aims to examine this problem with a flexible electropneumatic gripper to be produced using additive manufacturing technology. The flexible gripper is manufactured in two parts using a 3D-printed molding technique. The structure of the gripper consists of molded silicone (RTV-3015) and polyethylene terephthalate (PET) film made of chambers. These compartments are an active compartment consisting of 10 airtight compartments that can operate with compressed air, and a passive compartment covered with PET film. During the bending of the soft gripper, the PET film inside the passive chamber begins to be compressed by the compressed air, resulting in a higher load holding capacity of the gripper. In addition, the feedback module made of flexible sensor is integrated during fabrication. A real-time control experiment setup was created for the PID control of the flexible gripper. The step and trajectory tracking performances of the controller were observed. Finite element analysis of the gripper was performed with the COMSOL program to compare the accuracy of real-time experiments. The results of the experimental studies and the movement characteristics of the electropneumatic gripper, the relationship between the bending angle and the pressure, and the position tracking performance were investigated. The experimental results of the gripper were found to be in good agreement with the simulation results. Experimental results determined that the flexible gripper showed successful trajectory tracking performance with PID control algorithm.