Aiming at nonlinearity and uncertainty in the valve controlled asymmetric cylinder position servo system,an experimental method was applied to obtain the system s equivalent linear uncertainty model.

Because of the simple structure and small spatial volume, valve controlled asymmetric cylinder is widely applied in hydraulic servo system.

For using software method to make the valve controlled asymmetrical cylinder system has the ideal output, the defect such as asymmetry of the dynamic characteristic, bad stability, big over shoot and long adjusting time when .

Because nonlinear parameters such as long-pipe,valve-controlled asymmetrical cylinder and load disturbance had impact on leveling system of aerial platform.

Through considering the soft tube connection between valve and cylinder of valve-controlled asymmetrical cylinder hydraulic system,the system equations are constructed,and the two transfer functions on two directions-rod protruding and rod retracting respectively are derived,The gain and the natural frequency on two directions are also discussed.

According to the asymmetry and nonlinearity of the symmetrical valve controlled asymmetrical piston system, in order to improve control precision of the system, the work characteristic of the system is analyzed, then a new control method based on the cerebellar model articulation controller(CMAC) is advanced, and the CMAC compound controller is designed.