Abstract: For manipulators with interval uncertain parameters,evolving design methods of robust controllers are proposed based on the genetic algorithm.The encoded parameters of the controller with a given structure are taken as the controller population,and the encoded uncertain parameters of the plant as the plant population.A co-evolution operation is performed on the two populations to obtain a controller with sufficient robustness against the plant interval uncertainties and a plant model that achieves the worst control properties.Results of applications to robust controller design for a two-degree-of-freedom manipulator with parameter uncertainties demonstrate the efficiency of the proposed method.