PURPOSE:  To improve the safety associated with the operation of bulldozers on coal stockpiles by investigating the feasibility of remote-control operation.

RESEARCH SUMMARY:  Environmental conditions, coal compaction, and other factors can result in voids in coal stockpiles which can entrap bulldozers used to facilitate drawdown at the top of the piles. Since 1980, there have been 19 fatalities at coal stockpiles, the majority being bulldozer operators. Efforts by MSHA and others have led to development of improved cab designs, high strength windows, and communications which have proven to save operator lives during dozer cover-ups. Providing remote control of the dozer has the potential to totally eliminate the danger to the operator by removing him/her from the machine. Previous attempts to remotely control the dozer were never fully implemented due to a variety of issues. One drawback was that the operator, when removed from the dozer, lost the feel of the machine due to time lags in the controls. This resulted in significant inefficiencies during remote operation compared with on-board control. Addressing this issue, NIOSH has developed a new approach to remote-control which can closely mimic the feel of the machine for the operator by adding visual, audio, and vibratory cues. Both MSHA and ConsolEnergy have expressed a need for this work. The overall objective of this new project would be achieved through several phases. Phase I would investigate the feasibility of using a 360-degree camera installed on a dozer to provide visual feedback to the remote operator. This camera would continuously transmit a panoramic image to a receiver at the operator location. The machine operator, equipped with a head-mounted sensor that tracks head movement, would view an image that one would see if actually operating the machine. Dozer movements would be wirelessly controlled via joysticks at the industrial remote-control station using drive-by-wire technology with virtually instantaneous response. In conjunction with this feedback, a stereo sound system would replicate dozer audio in real time. The success of this initial phase would warrant a follow-up (Phase II) investigation to further refine and improve machine remote operation. Here, the feasibility of using a motion table to provide feedback of machine movement to the remote operator would be investigated. Such a system would use accelerometers on the bulldozer to sense movement. This data would be transmitted back to the remote operator seated on a motion pod incorporating six-degrees of freedom. Thus the pod would simulate and record machine movements. The anticipated outcome of a successful demonstration of a remotely-operated dozer would, in the long term, be an increased adoption of this method for stockpiles in mining. This development would result in a reduction in incidents and fatalities from dozer cover-ups by removing the dozer operator from the stockpile.