Key Technology Research On Excavating Frozen Soil With Hydraulic Excavator

In order to achieve the goal of excavating frozen soils, we change the mining methods of hydraulic excavators. By taking the means of theoretical analysis、modeling and simulation, we analyze the mechanism of reducing digging resistance of vibratory excavation; we also research vibratory excavation control system of hydraulic excavators. The researching results are verified by modeling and simulating.Firstly, vibratory excavation technology of hydraulic excavators and the mechanism of reducing digging resistance by vibrating excavation are introduced simply in the paper. We analyze the current researching and application status of vibratory excavation technology of hydraulic excavators at home and abroad, and also define developing trends of vibratory excavation technology of hydraulic excavators. Secondly, we get to know the destructing impacts from dynamic features of frozen soils、breaking criterions of frozen soils and vibratory frequency of signals by reading literatures. We introduce the parts of digging resistance of hydraulic excavators, analyze and compare some common mathematical models of digging resistance of hydraulic excavators. On this basis, we build the mathematical model of digging resistance of hydraulic excavators that are excavating frozen soils. We simulate and calculate the components of the mathematical model by using of SimulationX. Thirdly, we analyze the implementations of vibratory excavation of hydraulic excavators by changing the flow that flowing in and out of bucket cylinder. Then based on the electro-hydraulic proportional flow valve, we research and design the vibratory excavation control system of hydraulic excavators. We build the model of the control system by using of SimulationX, and also simulate the model. All of the simulation results certify the feasibility of the model theoretically. Finally, we add the mathematical model of digging resistance of hydraulic excavators to the model of the vibratory excavation control system of hydraulic excavators. And then, we simulate the united model by using of SimulationX. Compared with static excavation, the united simulation results certify the facts that vibratory excavation can effectively reduce the total digging resistance from frozen soils theoretically.The united simulation results also prove that the vibratory excavation control system of hydraulic excavators based on the electro-hydraulic proportional flow valve can ensure hydraulic excavators have the function of reducing digging resistance by vibrating excavation. When hydraulic excavators are excavating frozen soils by vibratory excavation, the values of digging resistance from soils are related with vibratory frequency、amplitude and amplitude value. Vibratory frequency、amplitude and amplitude value of the vibratory excavation control system of hydraulic excavators can be adjusted timely according to the different characteristics of job objects. If we want to change the vibratory frequency of bucket, we only need to change the vibratory frequency of signal; to change the amplitude of signal can change the amplitude of bucket; to change the amplitude value of signal can change the digging speed of bucket.When the bucket of hydraulic excavator is digging frozen soils, at the same time the bucket is also vibrating, this united actions of the bucket are not difficult to achieve theoretically. Therefore, adding vibration to the bucket of hydraulic excavator will provide hydraulic excavators with a new and favorable approach to excavate the frozen soils effectively.