Robust control of rotary crane by partial-state feedback with integrator

This paper deals with a simple design of robust control systems for rotary cranes. After deriving a simple linear model of crane dynamics, a constant gain partial state feedback controller is presented. Using information on the nominal natural frequencies of a load–rope system, the control system can be designed easily to be robustly stable for any rope length, without iterative computations. In addition, a method of including an integrator in the robust control system is proposed for reducing the positional error of the crane boom. The effectiveness of the proposed method is confirmed experimentally.