Sensitivity analysis is applied to an investigation of the influence of parameters on the dynamics of a variable displacement axial piston pump. Since an exact mathematical model of piston pump is complex and highly non-linear, the investigation of its dynamic characteristics for the variation of the system purameters by changing separate parameter values in sequence becomes very inefective. In this paper a parameter sensitivity analysis was employed to analyse the eflects of the system parameters systematically. The analysis was done on the exact non-linear dynamic model of the pump system which is represented by fourth-order dynamics. Based upon the simulation results, the degree of influence ofeuch parameter and the justification of order reduction are discussed in some detail.

The load-sensing hydraulic system is an energy saving hydraulic system which improves the efficiency of transmitting power from the pump to the load. However, its stability characteristics deteriorate critically due to the addition of the load-sensing mechanism, compared with those of the conventional system. In this pfi!per, a non-linear mathematical model of the load-sensing hydraulic system is formulated, taking into consideration the dynamics of the load-sensing pump. Based upon linearization of this model for various operating conditions, the stability analysis has been madt using the Routh-Hurwitz stability criterion. The results of the theoretical stability analysis were assured through experiments. Both results show that stability is critical to the choice of system parameters such as the setting pressure of the pump compensator and the load inertia. 3/88 0 IMechE 1988 0263-7138/88 $2.00 + .05