Dynamic analysis of an open-loop proportional valve controlled hydrostatic drive

This article highlights the dynamic analysis of a proportional valve controlled hydrostatic drive. Such drives are used widely in construction and mining applications. In the drive considered for the analysis, the speed of a bent-axis hydro-motor is controlled by varying flow supplied through a proportional direction controlled valve. A non-linear mathematical model using bond graph simulation technique is developed, where detailed model of the drive system including its loading arrangement is incorporated. From the test results of the pressure-flow characteristics of the valves, its port resistances are identified. Using them and taking into account various losses of the hydro-motor, the drive model is validated through experiments. The verified model is used to study the effects of the perturbations of some critical parameters on the transient responses of the hydrostatic drive through simulation. The proposed model may be useful for initial design of such drive and the development of control systems where these drives are used as actuators.

Formation of the Integrated Information Environment of a Radio-Electronic Equipment Design

Widely known method of combining of different information instruments of design support is formation of a common information space. However the modern nomenclature of software for the organization of a common information space not always considers specifics of a radioelectronic equipment production. In article the task on development of a mathematical model for the electronic designer document and formalization of interaction between design tools at all stages of a project cycle of a radio-electronic equipment is researched. The mathematical model of the electronic designer document with using of the subject-oriented ontology apparatus and theory of sets is offered. Dynamics of the electronic designer document life cycle is described by using of the automata theory, graphically the model of dynamics is presented in the form of the oriented graph, simulation modeling of dynamics was carried out in the numerical computing environment MATLAB with using of an extension packet Stateflow. Application area of use of the developed mathematical model is design and tests of digital receivers of navigation satellite signals. The hardware-software automated bench and software of interaction with management system the engineering data “Lotsman: PLM” within a common information space are developed for implementation of tests of the designed digital receiver

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

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.