Mining or in situ disintegration of hard material – Automatic control; signaling or indicating
Reexamination Certificate
1999-10-29
2001-03-20
Lillis, Eileen D. (Department: 3673)
Mining or in situ disintegration of hard material
Automatic control; signaling or indicating
C356S139030, C701S050000, C299S001400
Reexamination Certificate
active
06203111
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to mining machines. More particularly, the invention relates to continuous mining machines, and to methods and apparatus for controlling such machines.
It is known to use a laser to control mining machinery. See, for example, Anderson, D. L., “Framework for Autonomous Navigation of a Continuous Mining Machine: Face Navigation,”(USBM IC 9214, 1989), which describes a laser-based heading control system built by the U.S. Bureau of Mines. This system uses substantial infrastructure, and the method of extracting heading is quite different from the system described below.
There are also multiple examples of guidance and mapping of underground mining vehicles using inertial sensors and scanning laser range finders. See, for example, Makela, H. et al., “Navigation System for LHD machines,” Intelligent Autonomous Vehicles, 1995; Scheding, S. et al., “Experiments in autonomous underground guidance,” Proceedings of 1997 ICRA, 1995; Shaffer, Gary, “Two dimensional Mapping of expansive unknown areas,” PhD. Thesis, Carnegie-Mellon University, 1995.
SUMMARY OF THE INVENTION
The invention provides a mining machine comprising a vehicle body having forward and rearward ends, a cutter head mounted on the forward end for upward and downward movement relative to the vehicle body, and a conveyor mounted on the vehicle body for conveying material cut by the cutter head toward the rearward end. The machine also comprises a position sensing and control apparatus. The apparatus includes first and second generally vertical, generally parallel surfaces on the vehicle body, and an off-board light source emitting a light beam that strikes the surfaces. The apparatus also includes an imaging device for imaging both of the plates in a single image, and a computer receiving the single image from the camera, the computer using the single image to determine at least one of the roll, yaw and lateral offset of the machine.
In the preferred embodiment of the invention, the apparatus includes first and second generally vertical, generally parallel steel plates mounted on the vehicle body, and off-board laser emitting a beam in a generally vertical plane such that the beam strikes the plates. The apparatus also includes a camera mounted on the vehicle body, the camera having a filter so that the camera picks up only light having the wavelength of the laser, and the camera imaging both of the plates in a single image. The apparatus further includes a computer having a framegrabber and receiving the single image from the camera. The computer uses a Hough transform and thresholding to identify those pixels in the image that are illuminated by the laser, uses the identified pixels to calculate a least-squares estimate of the plane containing the laser beam in the reference frame of the camera, transforms the estimated plane into the coordinate plane of the machine, and computes roll, yaw and lateral offset of the camera from the estimated plane.
In the preferred embodiment of the invention, the position sensing and control apparatus also includes a gyroscope and/or an inclinometer used for temporary guidance if the laser is blocked.
In one embodiment of the invention, the mining machine further comprises a controller for steering the vehicle body using PID control, and the computer transmits the roll, yaw and lateral offset to the controller.
In another embodiment of the invention, the mining machine further comprises an operator display, and the computer transmits the roll, yaw and lateral offset to the operator display.
Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims, and drawings.
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Bares John
Campbell Bryan G.
Fromme Christopher C.
Herdle David K.
Herman Herman
Kreck John
Lillis Eileen D.
Price David R.
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