Theoretical and experimental studies of the steady-state performance of a primary and secondary-controlled closed-circuit hydrostatic drive

Abstract

In this article, performance of a closed-circuit hydrostatic drive in primary and secondary mode of operations has been studied through theory and experiment. This drive consists of a variable displacement pump that supplies pressurized fluid to a variable displacement hydro-motor of bent axis design. Bond graph simulation method is adopted for system modeling. In the model, the losses of the drive are accounted by suitable resistive elements, and their characteristics are identified through experiments. The predicted drive’s performances are studied with respect to the overall efficiency, torque loss (%), and slip at different torque levels which are also validated experimentally. The investigation made in the article identifies the efficient zone of operation of the drive which will be useful to the practicing engineers to select such a drive used in heavy constructional equipment. From the steady-state performance of the pump and the motor, their critical control parameters are identified. The studies may be useful for the design of the suitable control strategy to obtain the optimum performance of the drives.