Abstract: The main problems of airplane landing control and solving methods are discussed in this paper. H-infinity robust control for airplane landing is studied. A parameter-selecting approach is proposed to determine the weight matrics of high order Riccati equation. By using this approach the weight matrics are created randomly in a specified area, and the positive solutions of Riccati equation can be searched after repeated calculation. A robust H-infinity state feedback controller is developed. Simulations show that stability and speed of the landing period are guaranteed by using the controller presented. Both the advantages and disadvantages of the approach are addressed.

Key words: H-infinity control, Riccati equation, weight matrix, robust control, airplane landing control