| In order to meet all kinds of large-scale mining in open-pit mine, shovel loading of the coal and tailing materials as well as the needs of large-scale infrastructure construction, supersized hydraulic excavators have become increasingly widespread, representing the development direction of open-pit mining equipment. Generally multiple variable pumps, multiple main control valves and multiple actuators are used in supersized hydraulic excavators, what’s more, in practical operation, pump displacement needs to be dynamically changed and the corresponding relationships of the pumps, valves and actuators need to be dynamically switched according to different conditions, in order to make the actuators work in coordination. Research on the hydraulic control technology of supersized hydraulic excavators is still in primary stage in China, moreover, the position and speed of the working device, and the changes of system flow and pressure in the working process of supersized hydraulic excavators are still lack of basic knowledge, and there existing poor coordination, low efficiency and poor handling among the pumps, valves and actuators. Furthermore, the quality of the mechanical components of the working device is larger, the working device frequently lifting and falling, resulting in a large number of system energy loss and system heating in the process of falling, which has an important influence on reliable safety work of supersized hydraulic excavators.Aiming at the above problems, 300 tons of supersized backhoe hydraulic excavator was researched in this paper, and the main work is as follows.(1) Structure and working process of supersized hydraulic excavators were analyzed, and the hydraulic system of working device was analyzed and designed, including analyses of principle for the flow control and constant power control of the main pump, and the series-parallel relationships of the multi-way valves of the main valves. Then the flow distribution methods of hydraulic system for working device were researched and flow regeneration control loop was designed.(2) The co-simulation model of the mechanical-electrical-hydraulic integration of the working device was established based on ADAMS and AMESim.(3) In the no-load condition, the same control signal was input into, single actions of the boom, arm and bucket were simulated and experimented, and comparative analyses of the test data were carried out.(4) Efficiency and utilization of flow between flow regeneration loop and the original system were researched and comparative analyses were carried out.(5) Digging resistance and gravity load during the digging process were analyzed and simulated, what’s more, under the flow distribution scheme of typical working process and designed pilot control signal, the dynamic characteristics of the loading process for excavators were analyzed.The results show that, under the same control signal, the simulated data and experimental data of single actions are basically the same, moreover, the pressure trend is consistent, verifying the correctness of model established. Furthermore, the comparison between the flow regeneration loop and the original system shows the boom can go down separately by its dead weight, so that more flow will be provided by the main pump for other actuators, improving the work efficiency and the effect of energy saving. What’s more, the pressure, force, flow and velocity of cylinders in the working process are researched, obtaining the dynamic characteristics. Finally, the actuators can work in coordination under the situation of loading efficiency, verifying the correctness of the flow distribution. The above study can provide guiding significance for further research on flow distribution and flow regeneration for supersized hydraulic excavators. The above study can provide guiding significance for further research on hydraulic control technology of supersized hydraulic excavators. |
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