Abstract: The butterfly characteristic between the speed of piston and the pressure of oil in hydraulic position control system is analyzed, and a kind of adaptive compensation method is proposed. The method can compensate the nonlinearity of piston’s movement in different directions, reduce the influence of load force from hydraulic cylinder piston’s velocity effectively, and also improve dynamic performances of the system. The method has good applicability in that parameters used to choose compensation coefficients can be obtained from field meters directly or just through simple transforming. It is applied to domestic hot strip plants, and has good performance.

Key words: Adaptive compensation, Hydraulic position control, Servo valve