Hybrid Computer Simulation for the Investigation of the Automatic Steering of a Twin Drum Coal Shearer by Microcomputer

The process by which a single drum longwall coal-cutting system is steered vertically through an undulating coal seam has been previously investigated. This work demonstrated initially that several discrepancies existed between theoretical models and actual performance. It was shown theoretically that the delay between the coal thickness measurement by nucleonic sensor and the actual coal cutting action contributes to system instability. Analysis of the process has demonstrated that by storing the previous pass data on a remote computer the system can be stabilised and this has been substantiated by the use of a 1/4-scale physical model. Recently, the possibility of the automatic steering of a twin drum shearer cutting simultaneously the roof and floor of the coal seam has been considered. From theoretical considerations it seems possible that a local microcomputer can achieve the required optimum control of the twin drum shearer dispensing with the remote computer. For the purpose of analytical studies, a hybrid computer simulation of the process allowing for bi-directional cutting and the associated microcomputer control system have been constructed and is described in this report. The model and controller have been constructed to represent realistically the operation required in the difficult environment at the coal face.