A new step in sensors

The mining industry is swiftly moving into its next era – the age of automation – and while this is creating massive boosts in efficiency and productivity, it is also creating new risks.

Heavily laden autonomous trucks criss-crossing the mine site at relatively fast speeds present a real danger to other, human operated vehicles, particularly light vehicles.

The situation has even become so serious the NSW Department of Trade & Investment: Mine Safety has even called for separate haul roads to be developed for light and heavy vehicles.

One of the ways being developed to overcome this massive safety issue is through high level proximity detection and collision avoidance systems, which is gaining in importance for the industry.

In a survey carried out last year Timetric asked 110 mine managers, maintenance managers, procurement managers and other key decision-makers in over 90 Australian mines, questions related to each company’s current investment intentions for technology, and their views on the future of autonomous vehicles.

Over 30 per cent of respondents said they were considering investing in the technology within the next two years with the key driver being ‘safety’.

Globally in the United States and South Africa, miners are already on board with the proposed changes, as government recommendations for new legislated rules around the use of proximity detection on mobile mining machines have been in talks since 2013.

But despite the big push for safety, not all proximity detection technology is built to endure the rigours of the mining environment.

In a bid to not only making mining safer, but make mining more productive, ifm efector have developed a new, rugged, plug-and-play sensor that provides three dimensional detection of scenes and automatic detection of objects.

The new O3M sensor is a PMD sensor designed for area surveillance and movements, capturing it in a single image, using infrared technology.

This technology also captures these images in three dimensions and without motion blur, aiding precision in detecting and monitoring moving objects at depth.

Additionally, by using infrared rather than cameras the technology is immune to the effects of dust on the lens, and is able to work across a variety of different materials.

“Thanks to the PMD technology is it possible to have a high repeatability of the measured data even on materials of different reflectively,” ifm efector said.

The sensor sets itself apart from other proximity detection units in the field, due to it being fully encased, and featuring protection ratings IP67 and IP69K, meaning it is completely protected against ingress from the dusty environment encountered on a mine site.

Added to this is a capacity to automatically suppress background illumination, ensuring reliable recognition even with full solar radiation of 120 klx, or interference by high powered vehicle lights.

It is also able to operate in a wide temperature range, from -40 degrees Celsius through to 85 degrees Celsius, ensuring it can take both ambient and vehicle and machinery operating temperatures.

In regards to vehicles operating autonomously in areas that may have people in them, an integrated automatic object recognition system detects up to 20 stationary or moving objects in the path of the vehicle, and by comparing the current speed, the motion vector, and fixed parameters such as breaking distance the collision probability is calculated by the 3D sensor and then transferred to the machine control system via CAN bus or Ethernet, or alternatively, signals the driver.

This integrated distance monitoring also provides up to 64 adjustable regions of interest

For automated vehicles path monitoring can also be part of the system, with a freely adjustable reference point on the vehicle allowing for applications like obstacles of pre-defined heights above ground to automatically be detected as an obstacle.

ifm efector’s sensor also has an automatic vehicle tracking program.

A special classification of reflective objects is used to aid in tracking the vehicle ahead.

“For example, the minimum and maximum distance to the vehicle ahead is set or recognition is limited to a certain arrangement of reflectors via various parameters,” ifm efector stated.

“Additional collision prediction ensures that obstacles are reliably detected and signalled to the machine control system in two stages.

“Interference by direct solar radiation or other 3D sensors is automatically suppressed.”

It has an operating distance of 35 metres, but can detect people even further way if they are wearing reflective vests.

The sensor has a pixel resolution of 64 x 16 and a maximum field view size of 49 x 14.37 metres.

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