Dynamic analysis and control of a string-stiffened single-link flexible manipulator with flexible joint

In this paper, an innovative method of controlling the endpoint precision of a single-link flexible manipulator has been presented. The flexibility of the link has been stiffened by using a pair of strings while retaining its advantage of being lightweight. The flexible link is modeled as an Euler-Bernoulli beam. Dynamic analyses of the string-stiffened single-link flexible manipulator (SSSLFM) with flexible joint have been carried out using Euler-Lagrange's formulation with the assumed mode method. The effects of string-stiffening on tip deflection of the link have been found. Coupling effects of string vibration on tip deflection of the link as well as on the joint of the manipulator have also been investigated. It has been observed that by the stiffening of the flexible link with a pair of strings, tip deflection of the link has been reduced significantly. Residual vibrations have been controlled by applying robust proportional-integral and derivative (PID) control.