The load on the cutting boom of roadheader changes violently because of the changes of rocks hardness. The power of cutter motor is related to the hardness of rock and propulsive force. The propulsive force is determined by the moving speed of cutting boom. The hydraulic control system of arcing cylinders is an electro-hydraulic proportional control system. The adaptive control model is build by Simulink. A PID control is used and the power of cutter motor is keep at a constant state by adjusting the speed of arcing cylinders.
To efficiently decompose a large complex STL model, an improved boundary extraction method is proposed based on genetic algorithm. Three curvature parameters (dihedral angle, perimeter ration and convexity) were used to estimate the surface curvature information. Genetic Algorithm (GA) is used to determinate the threshold of feature edge. The discrete feature edges are grouped and filtered using the best-fit plane (BFP), which is calculated by Least Square Method (LSM). Several experimental results demonstrate that the amount of feature edges is about half of the preset threshold method, and useful feature edges were reserved. The extracted feature boundaries can be directly used to decompose large complex models.
The cable between elevator and cage was used as the object of this study, we use the finite element theory to establish the finite element model of the cable system. Then the motion response curve between the elevator and cage and the tension curve of the cable was gotten from solving the finite element equation by using the Runge-Kutta method. We have studied the effect of the length of the cable on the motion response between elevator and cage.
The scene model is extremely complex in the 3DVR remote control platform for shearer. In order to speed up the 3D scene rendering of 3DVR remote control platform for shearer and reduce computational load of the system, we simplified the scene model based on LOD technology. The LOD algorithm was designed, in which the computing method of simplification rate, the algorithm of Triangle mesh simplification based on contraction and data structure of original mesh was described. Two shearer drums were simulated in the XNA platform via the above method. The simulation experiment results show that LOD model generated by the LOD algorithm have almost no loss in the visual effect, meanwhile the complexity of the scene model is reduced and the scene rendering speed is improved.
Automatic" and "less people" in fully mechanized working face is the target of China's coal industry development, and the key to achieve this goal is the automation of coal mining. According to the previous technology of memory cutting cannot adapt to the complicated geological condition in China, this paper proposed the technology of shearer self-adaptive memory cutting based on fuzzy control theory, the shearer positioning system and fuzzy control system of self-adaptive cutting. These systems can get the message of shearer's position and attitude at any point, trace the memorial cutting path automatically, judge whether the shearer cuts rocks based on fuzzy control theory and find the optimal scheme when it works. The authors make the experiments of path tracing in laboratory and the experiment of shelf-adaptive adjust in Xi'an Coal Mining Machinery. All the experimental results show that this technology not only can realize the shearer memory cutting, but also can discriminate the abnormal state of shearer cutting rocks, then adjust the drawing speed and drum height automatically.
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