| Hydraulic excavator is one of the most widely used engineering machinerybecause of its high efficiency, durable and strong abaptability. It plays an importantrole in economic construction. However, hydraulic excavator have been paid muchattention in the field of energy saving and environment protection, for the reason oftheir large application quantities, high fuel consumption and bad emission. Highefficiency and energy saving have been one of the main aims to be puesued byexcavator manufactures. Hence, many excavator manufactures and institutes at homeand abroad have done much research on energy saving.Energy recovery is an effective way to save energy for hydraulic excavator.Based on the analysis of the working deveces in hydraulic excavator, a system ofboom potential recovery system for hybrid hydraulic excavatoe is proposed. Thesystem scheme has been designed, and the parameter matching has been researched.The simulation model of the proposed energy recovery system has been establishedusing AMESim software. The influence of the key parameters on the energy recoveryefficiency has been analyzed. According to the characteristics of the conventionalhydraulic excavator, a new control strategy of the energy recovery system is proposed.The main work of this paper is summarized in the following:1This part introduces the mean of energy saving in hydraulic excavator, thedevelopment of control technology in energy saving such as improving theperformance of hydraulic components and power matching, the development andapplication of hybrid system, the application of present energy recovery system. Thenecessity and feasibility of designing a suitable energy recovery system for hybridhydraulic excavator are shown. The content and the research about the topic areoverviewed.2Design of boom potential recovery system for hybrid hydraulic excavator. Thekinematics’ analysis of excavator working device is done by D-H method andtransformation matrix is derived which every coordinate on the basis of the firstcoordinate to achieve a coordinate transformation between the different coordinate.Simulation model of the working device in conventional hydraulic excavator is builtby AMESim software. By analyzing the excess energy of three hydraulic cylinders inthe conventional hydraulic excavator during a working period, a new boom potentialenergy recovery system for hybrid excavator is proposed. The system schematic is designed and implementation plan is analyzed.3Modeling and parameters matching of hydraulic components for the energyrecovery system are done in this chapter. The models of pump, hydraulic motorcylinder, accumulator and line in the proposed energy recovery system are built. Thetransfer function and hydraulic natural frequenct of the energy recovery system areobtained. Several methods for increasing response speed are proposed throughanalyzing the influence of variable and fixed parameters on the natural frequency. Theparameter matching methods of the engine, hydraulic motor and accumulator areestablished and the specific parameters and model are selected. Parameter matchingmeets the need of the system condition, and improves the energy recovery efficiency.4Influence of key parameters on energy recovery efficiency are analyzed. Modelof the boom potential recovery system is built. The influence of accumulator aerationpressure and initial volume, the type and displacement of motor on the energyrecovery efficiency are analyzed. Accoding to the simulation results, all causations ofenergy loss are analyzed.5Control strategy of the proposed boom pontential recovery system for hybridexcavator is simulated. Models of the engine, motor and battery in hybirdexcavatorpower system are built. According to the load characteristic, control strategy based onthe working condition and SOC of battery is proposed. Simulation models of theconventional hydraulic excavator and the new energy recovery system are built byAMESim software. Model of the proposed control strategy is built by simulinksoftware. The co-simulation for the hybrid hydraulic excavator system is established.The simulation results testify the validity of the proposed control strategy.6All the work and conclusions of the paper are summarized. The future researchsirection is proposed. |
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