Dynamic Virtual Study On The Scene Of Fully Mechanized Mining Face And The Collapse Of Overlying Strata

Coal mining is a complex time-varying system, in which various factors such as man, machine, and environment interact with each other, the tough underground work environments, complicated geological conditions and the mixture of different environmental factors give rise to the limitation of many traditional technology, especially in fully-mechanized face and roof. Conventional method had not only to guarantee the experimental environment, but also to demand a large cost while the process is dangerous and the result is hard to verify. Therefore, in the information age, the combination of VR technology and coal industry in researching the scientific cognition of coal mining environment is becoming a new method to solve the safety problem in coal mine production.Roadway data information was classified into measurement data, section data and attribute data in the paper. Roadway was classified into three elements: body, arch and node according to data structure of arch and node. Five datasheets of arch, node, traverse point, section and attribute were set up. Topological relations of body-arch, arch-node and body-node were analysised. Section Modeling method based on laneway midline was provided, namely calculate the coordinate of the median point of laneway midline with traverse point data,draw a series of line frame models of the laneway section at the midline; connect them with lines to form laneway surface model; describe the section features with four archs: up, down, left and right; finally 3D Model of the whole roadway was created after treated with texture mapping.Modeling characteristics and methods of virtual scene were analysised in the paper and OpenGL was chosed as modeling tool. Mine stope equipment model was set up through three steps: geometric modeling, image modeling and behavior modeling. Dynamic characteristic of fully mechanized mining equipments was analysised by using kinematics and dynamics. The behavior modeling of powered supports was set up with the method of constrained inverse kinematics, and shearer was established with the method of father-son hierarchical model. Powered supports and shearer can be controlled with the application of selection mechanism provided by OpenGL and virtual controller operated by mouse. By setting system timing device, using clock to control the operation of mining equipment and the applying of 3D animation double buffer technology, the dynamic simulation of the production process can be achieved at last.This paper summarized the research results of movement law of overburden rock, divided the overlying strata into five categories: soft collapsed roof, first medium collapsed roof, second medium collapsed roof, hard roof and bending plastic roof. Based on the model of the line box modeling method, the dynamic model of overburden rock was also established. According to the data of overlying strata, the system can automatically estimate the category of roof structure, calculated and determined parameters such as the number and thickness of immediate roof, and the number and position of key strata, broken order, the first collapse and the cycle collapse pace of the main roof. The overlying strata movement can be simulated no matter which happens at anywhere or on anytime. The system can promote the visualization of the collapse of different roof structure, and it provides us a new idea of studying the underground pressure and the strata movement, which can verify the underground pressure hypothesis about the classical model of overburden rock movement.The vivid representation of the complex underground scene result in the declination to computer operation speed, this paper used the simplified models, examples, partition and fog technology to improve the image rendering speed, met the requirement of VR about real-time. It had also designed methods such as scene roaming, spot controlling, position querying and collision detection. By using Visual c++ and OpenGL, the VR- mine system based on the PC was developed, reappear the operation in fully-mechanized scene and collapse of overburden rock realistically.