Proximity detection systems (PDSs) on underground mobile haulage equipment are intended to protect mineworkers from striking, crushing and pinning by slowing and stopping the vehicle before a collision occurs. However, highly variable and changeable environmental and vehicle conditions can drastically alter PDSs performance, and the magnitude of these effects is not clear. Furthermore, overly conservative setups can interfere with other work, making it difficult to appropriately configure these systems. NIOSH researchers leveraged their existing VRMine simulation and proximity detection system expertise to examine these problems. This paper presents the results of a deterministic simulation exploring the sensitivity of vehicle stopping distance to a variety of environmental, vehicle, and PDS configuration variables. The simulation was uniquely created using the Unity game engine and PhysX physics engine to simulate the time based relationships between friction / slip, vehicle performance, and PDS behavior in order to leverage the visualization component for improved communication of the results. Using this simulation, over ten thousand trials were run on a range of variables such as slope, friction, vehicle type, load level, braking behavior, and PDS configuration. Values for the physical parameters were derived from a large number of sources including manufacturer specifications for vehicle parameters, field observations of existing PDSs, and field measurements. The model was validated with results from lab tests of a loaded and unloaded scoop on pavement as well as some unloaded field measurements in underground mines. The results of this simulation will be used to develop guidelines on the configuration of PDSs based on mine environment and vehicle parameters. The visualization afforded by Unity will also be used in real-time VR applications to communicate the results and compare different configurations.
Simulation
Simulation and sensitivity analysis of mobile proximity stopping distance in Unity
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