Hydraulic Excavator Working Device Optimization And Operating Performance

As one of the most important earthworking construction machinery and equipment, hydraulic excavator is commonly used in house building, urban construction, pipeline laying, garden planting, mining exploration, national defense construction, agricultural irrigation and other infrastructure. The working performance of the backhoe working device is the most important symbol of the machine. Combining the national 863 project and the key scientific research program from enterprise, the aim of the thesis is researching on working performance analysis and integrative optimization of kinematics and dynamics. A general program is written under the Visual Basic 6.0 programming environment, which is used for working performance analysis and integrative optimization. The main research work as follows:The development of hydraulic excavator and research on working mechanism of excavator are surveyed. The market and perspective of hydraulic excavator are analyzed. The defects of homemade excavator is analyzed compared with inward ones.Full kinematic and dynamic models of the excavator working mechanism are derived, then a calculational module based on kinematics and dynamics is programmed to give results of kinematic and dynamic parameters. The three dimensions solid model for working mechanism is derived exactly by combining experiment with theoretical research. Based on the solid model, kinematic and dynamic simulations are also presented in ADAMAS. Both the simulation result and programmed calculation are consistent.Mechanical model of the excavator working mechanism is derived and limiting factors, which can affect working performance of excavator are analyzed. A visualized working performance analysis software is programmed to draw the working performance map. The working performance map is one of the most important methods that assess the design rationality of excavator attachment. The working performance data points figure, which can reflect the digging force on the teeth of bucket,power utilization of hydraulic pump and three hydraulic cylinders' matching and so on.Under special working attitudes, the tool forces and cylinders' pressure are tested synchronously. The analysis software is modified based on test results. The veracity of the tool forces model and reliability of the analysis software are validated at the same time.The optimum design model is established, which chooses the working performance in particular areas as the optimizing goal and uses the movement performance and mechanical properties to build up the constraint conditions. Given the genetic algorithm to optimize the working mechanism of the SWE 85 hydraulic excavator, the results show that the defects of the original design are avoided and the excavating performance is improved.Researching on working mechanism optimization and working performance analysis in this thesis developed design and optimization theory of hydraulic excavator, which is of great value and significance for improving excavator working mechanism.