Study On Rigid-Flexible Coupling Performance And Optimization Of Front-End Working Mechanism Of WK-75 Mining Excavator

Mechanical excavator has the characteristic such as high yield、 high efficiency、high cost, playing an irreplaceable role in open-pit mining activities. In the western region in recent years, there have been large mines into production and mechanical excavators’ demand began to increase. Excellent excavator performance can not only improve the efficiency of mining,improve the service life of the machine, also reflects the strength of the national heavy machinery manufacturing. In the process of mining, the front-end work performance is good or bad directly affect the excavator working effect of the machine. Get better the front-end work organization characteristics can have very important significance.The work is supported by the national high technology research and development program(863 program)—“Development of 75m3 Large Scale Open Pit Mechanical Mining Shovel(NO.2012AA062001)”. This article conducted research on front-end working mechanism of WK-75 mining excavator.Main research contents are as follows:First of all, to delve into mechanical excavators of excavating trajectory for further discussion. Through Analysis of the logarithmic spiral trajectory theory derivation,that is not perfect.Using the theory of mechanism kinematics with push speed change of the actual mining trajectory equation is more reasonable.Secondly, relying on the excavating trajectory equation, we can establish the mathematical model,such asmining Angle、the Angle of the hoisting cable、the center line of the arm、mining volume、initial launch Angle、discharging Angle、maximum cutting thickness and digging resistance. Using the latest methods of modeling with the wire rope and establishing multi-rigid-body model of digital prototype in ADAMS,measuring the angle changes of behind the cutting angle and the angle between hoisting cable and the center line of the arm in the mining process. At the same time,we discuss the differences between the virtual prototype trajectory、kinematics trajectory and logarithmic spiral trajectory.Once again, we made the modal neutral file of moveable arm and stick in patran and import the file into ADAMS to establish rigid-flexible system of WK-75 mining excavator.We discuss the differences between the multi-rigid-body system and the rigid-flexible system in severl motion parameters. For moveable arm and stick in the important conditions over the main mining process, the change of the stress were studied and we obtained the stress variation law in the process of mining which lay the foundation for subsequent fatigue analysis.That can provide reasonable dynamic stress spectrum.Finally, setting hoisting speed、push speed and mining location parameters as design variables.Choosing the structure size and excavation volume as constraint, selecting minimum angle of change behind excavation angle and the angle between the hoisting cable and the center line of the arm as the objective function. Selection of nonlinear quadratic programming Pointer algorithms, Isight co-simulation with Matlab optimization design.The optimization result carries on the analysis comparison test before and after optimization effect.