Research And Application Of Key Technologies For Fuel Consumption Control Of Large Mining Dump Truck In Open-Pit Mine

In essence,the open-pit mining process is a large amount of soil and rock transportation project.At present,large-scale open-pit coal mines in China are mainly transported by large-scale mining electric wheel dump trucks with a load of more than 100 tons,and their fuel consumption is huge,which has become the core of transportation cost control of mining dump trucks.Taking three open-pit mines of China Coal Pingshuo Mining Area as an example,from 2016 to 2018,the fuel consumption cost of mining dump trucks was 750 million,960 million and 1.25 billion yuan respectively,accounting for up to 22%of the total cost.The peeling volume of mining dump truck transportation was 2.2 billion cubic meters.Therefore,this thesis focused on the fuel consumption mechanism and key optimization technology of large dump truck in open pit mine.On the basis of summarizing the main problems of large fluctuation and consumption of fuel consumption of dump trucks in open pit mines,this thesis taken the key technologies of fuel consumption control of large dump trucks in open pit mines as the main line,determined the multi-dimensional characteristic parameters of fuel consumption based on the fuel consumption rate model from the whole process of man-machine-ring-pipe,and preliminarily established the fuel consumption control platform of dump trucks in open pit mines with the monitoring technology of Internet of Things as the core,which can provide data basis for the fine research of key technologies of fuel consumption control.Secondly,based on the fuel consumption rate model,reasonable key technologies of fuel consumption control were selected,and massive data obtained by field sensor monitoring were applied to obtain the internal relationship between the fuel consumption of mining dump trucks and key factors such as road working conditions and drivers’operating habits,and key technologies such as quantitative prediction model of fuel consumption of mining dump trucks,transportation road optimization model,road roughness reconstruction model,driving style identification model and fuel consumption control platform were established.Finally,through the practical trials in Huolinhe South Open-pit Mine and Pingshuo Antaibao Open-pit Mine,it was proved that the key technology of fuel consumption control of large-scale mining dump trucks proposed in this paper has become a new technology to effectively monitor and control the fuel consumption of large-scale dump trucks in open-pit mines.At the same time,it provided an advanced and reliable new technology for the transportation efficiency assessment of dump trucks,the maintenance quality of transportation roads,the improvement of drivers’driving skills and the optimization of transportation roads,and the reduction of transportation costs in open-pit mines.(1)This thesis took a Belaz-75306 mining electric drive truck as the research object.Based on vehicle dynamics and other methods of the first-principal,a fuel burn model was developed to simulate the major components of power output of the engine in a working condition.A simple and easy-to-use formula for estimating fuel consumption of electric drive dump trucks was proposed,which can quantify the influence of load,speed,rolling resistance,and slope resistance on fuel consumption.Secondly,taking an open-pit mine as an example,a highly-precise and reliable volumetric fuel consumption sensor was introduced to verify the accuracy of the fuel consumption estimation model of mine electric drive dump truck.Finally,based on the multi-dimensional characteristic parameters of fuel consumption rate model,fuel consumption prediction models such as limit gradient lifting tree,nearest neighbor,support vector machine,neural network and random forest are established,and the prediction accuracy was compared with that of fuel consumption rate model.The results show that the prediction accuracy of fuel consumption rate of mining electric wheel dump trucks on A-B1 and A-B2 transportation trunk roads was 6.4%and 6.9%,respectively.The evaluation index MAPE of XGBoost fuel consumption prediction model with multi-dimensional characteristics was 8.78%,so the prediction accuracy of fuel consumption rate model was better than XGboost model with multi-dimensional characteristic parameters.The research results can be applied to formulate reasonable fuel consumption assessment index,truck scheduling strategy and cost budget scheme,and reduce the fuel consumption of mining dump trucks in open pit mines.(2)Taking Komatsu 730E as the research object,a seven degree of freedom vehicle dynamics model was established.Based on the kinematics differential equation of non suspension mass,the calculation formulas of tire load and tire deformation were derived.Secondly,the time domain integration method of fast Fourier transform band-pass filter was used to eliminate the acceleration noise signal outside the 0.5-10.0 Hz frequency band,and the relative displacement of the non suspension mass was calculated,so as to solve the problem that the displacement cannot be accurately measured due to the limitation of the hydro pneumatic suspension structure of the mining truck.Finally,based on the tire deformation and the relative displacement of the non-suspended mass,the geometric model of the haulage road defects was constructed with sufficient accuracy to realize the ability of identifying and repairing local road defects.In addition,the dynamic load coefficient was calculated for the dynamic load and static load of the mining truck to indirectly quantify the roughness of the transportation road.The field test was carried out in Antaibao open-pit mine,and the results showed that the error of the geometric size reconstruction model of open-pit transportation road defects wa less than 20%.,which provided a quantitative basis for the maintenance of open-pit transportation road and improves the overall quality of road surface,reducing fuel consumption and carbon emissions of mining dump trucks.(3)Based on the digital elevation model of Huolinhe South Mine,taking R~2 as the evaluation index of interpolation accuracy,the exponential model was selected as the semi-variogram theoretical model by cross-validation method,and ordinary Kriging method was used to complete the interpolation of grid elevation data in blank areas.Secondly,considering the factors of dump truck load,running speed,road slope and road rolling resistance coefficient,the fuel consumption cost grid was dynamically constructed based on the fuel consumption rate model;The normalized fuel consumption and terrain elevation were taken as comprehensive costs and introduced into the loss function of A~* algorithm.On this basis,based on the improved transportation road route selection algorithm model,the road route selection scheme with the smallest cumulative cost distance was found.Finally,based on the fuel consumption rate model,the best fuel saving slope of the access ditch was determined to be 8%;Based on the balance equation of centrifugal force and friction force,the minimum turning radius of the road was determined to be 80 m,and the route selection results of the transportation road were smoothed and optimized The width of transport road was determined to be 35 m based on the width and safety distance of dump truck.Taking Huolinhe South Mine as a simulation case,the starting point and end point of two transportation roads,which from the distribution mining area to the south inner dump and from the third mining area to the crushing station were designated respectively,and the three-dimensional design of transportation road route selection in Huolinhe South Mine was completed to support the efficient and safe transportation operation of mining dump trucks.The layout of ramp directly affects the transportation cost and efficiency of mining dump trucks in open-pit mines.The research results have certain guiding significance for the road planning and design of open-pit mine development transportation system.(4)Using objective driving behavior data analysis method,based on the same mining dump truck and transportation road,111 heavy-duty natural driving behavior sample units and 108 empty-load natural driving behavior sample units were obtained through the monitoring system of mining dump truck drivers’natural driving behavior.Using a k-means clustering algorithm,driving style can be divided into three types:normal type,soft type,and aggressive type,and we verified the validity of this driving style classification with a box plot.On this basis,the parameters of random forest,k-nearest neighbor,support vector machine,and neural network models were optimized and the accuracy was compared through a cross-validation grid search,and then a driving style identification model based on the random forest method was finally proposed.Driving style parameter weight values were obtained based on the Gini coefficient.Last,the fuel consumption characteristics of different driving styles were calculated.The results show that the driving style identification models based on random forest can effectively identify different driving styles when the mining truck is operating under heavy load and no load,and the overall accuracy of the model is 95.39%and 90.74%respectively.The fuel consumption of the aggressive driving style was the largest and was 6%higher than the average fuel consumption.The research results provide data support and new ideas for operation training and fuel-saving driving of mining trucks in open-pit mines,reducing fuel consumption and carbon emissions of mining dump trucks.(5)Based on advanced sensing,wireless communication and other technologies,the fuel consumption,load,speed,slope,haulage distance,lift height of dump trucks were dynamically sensed in real time,and the fuel consumption control platform of dump trucks in open pit mines was built to complete the overall structure of data collection,transmission,storage,pretreatment and display.Secondly,the system integrated the models of fuel consumption pattern,dynamic load coefficient and driving behavior identification,realizing the functions of fuel consumption monitoring,assessment index formulation,road roughness monitoring,abnormal fuel consumption alarm,driving behavior monitoring,and established a closed-loop management process from data collection,statistics,analysis,processing and feedback,Dynamically optimized the fuel consumption of mining dump trucks and improved the automatic management level of fuel consumption of dump trucks in open pit mines.The research results had been applied in Huolinhe South Mine and Pingshuo Mining Area.Taking Huolinhe South Mine as an example,the unit consumption of SF31904 and Belaz-75306 mining dump trucks decreased by 2.9%and 4%respectively,saving about 8 million yuan in fuel cost and 3,500 tons of greenhouse gas emissions annually,which achieved good economic and social benefits.