The bending control of the soft pneumatic fìnger

Abstract

A soft finger is derived from the multi-chambers structure of PneuNets actuators. It includes the top extensible layer with ten pleated chambers and the bottom constraint layer. This soft finger is made of the same silicone rubber material, and the thickness of the bottom layer was increased to replace the hard material as the constraint layer. A model between the bending degree of the soft finger and input pneumatic pressure is constructed to describe the bending characteristics. And the finite element method is utilized to analyze the behaviors of the soft finger. It can be seen that the bending angle will fluctuate with the fluctuation of the input pneumatic pressure. The purpose of the bending control is to reduce the pressure fluctuations in the inner cavity of the soft finger through the control strategy. The bending control is realized by PID, PI, nonlinear PID, and PID based on the endocrine system (ES-PID). Compared to other algorithms, the ES-PID controller can improve the positioning accuracy and better adjust the pressure fluctuations in the inner cavity of the soft finger.