The U.S. Bureau of Mines seeks to increase safety and efficiency in U.S. coal mines by utilizing computer technologies to meet these goals. The technology required for a computer-assisted mining machine requires development of subsystems for machine intelligence, navigation-positioning, and computer control. This report focuses on one subsystem, an onboard heading system, which would be responsible for determining and controlling machine heading (direction of travel). The onboard heading system is a multisensor, computer-based system that determines machine heading, pitch, and roll. A directional gyroscope provides heading (yaw), fluxgate sensors provide compass data, and gravity-referenced clinometers give machine pitch and roll information. The system utilizes a dedicated microcontroller networked to an external system of computers. Tram commands, supplied to the network from external computers, are executed by the onboard system. Sensor feedback is employed for closed-loop control of machine heading by controlling pivots and turns. This paper presents the operating limitations and error sources of the system, along with implementation of closed- loop control of machine yaw. Results from mine machine tests are used to exhibit the various sensor shortcomings and to evaluate heading control during tests of machine pivots and turns.
10th WVU Int'l. Mng. Electrotech. Conf., Morgantown, West Virginia, 7/24-27/90. West Virginia Univ., PP. 79-83