Stability analysis of a new control scheme for a three-degree-of-freedom flexible arm under tip payload changes

This paper describes the stability analysis of a new control scheme for a three degree-of-freedom flexible arm under tip payload changes. The arm was built with light links, has most of its mass concentrated at the tip, and uses a special mechanical configuration to approximately decouple radial tip motion from angular motions. This special configuration facilitates the modeling and control of the arm. A two nested loop controls the tip position. The value of the tip mass is used as a parameter to design the outer controller. Theoretical stability analysis of the controlled arm is carried out when the tip mass differs from the mass used to design the outer loop. Experimental results are presented