Abstract: The pump-controlled technology has wide application in engineering machinery, heavy machinery and other fields. However, there are few analyses on its output characteristics at present. To explore the effect of the critical parameters of the pump control system on the output characteristics of the system, based on the state equations of open circuit pump- controlled asymmetric cylinder systems, the first-order trajectory sensitivity equations are derived and the sensitivity function curves of each parameter are obtained. Two measures of peak sensitivity and mean sensitivity are proposed to analyze the influence degree of each parameter variation on the displacement output characteristics. Based on 0.6MN pump-controlled hydraulic forging test bench, the accuracy of sensitivity theory analysis is verified. Experimental results indicate that in no-load time, servo variable pump 2 pilot servo valve gain, servo variable pump 2 and servo variable pump 1 pilot stage servo valve time constant has great influence. In load, that value of the sensitivity indexes of two parameter of each parameter is similar, in which the gain of pilot stage servo valve of servo variable pump 2, time constant and oil cylinder area and flow gain and system ratio gain are greatly affected. All the research above can provide theoretical basis for pump-controlled asymmetric cylinder systems performance optimization.

Key words: asymmetric cylinder, pump-controlled system, sensitivity analysis, state equations