Mechanical Technology February 2015

⎪ Innovative engineering ⎪

Industrial radar and rough materials handling

Reik Winkel (left), executive director of indurad, an industrial automation solutions company founded in Germany in 2008, talks to MechTech about the safety and productivity advantages of protecting and optimising expensive materials handling equipment with radar-based monitoring, operator assistance, collision avoidance and automation solutions.

W inkel’s company name, while chosen to combine the words “industrial” and “radar”, also borrows its meaning from the latin word ‘indurare’: to make hard or to improve, a name that came to him during his years as a student. He explains: “I was trained as a mining engineer. During my internship years, I spent several years studying dif- ferent mining operations: at Codelco’s copper mines in Chile; the Goonyella underground coal mines in Australia; and at lignite mines in Germany. “I noticed that on big expensive min- ing machines, almost no information was being made available to operators. When you buy a modern car, you get an automatic park assist system based on a proximity sensor to help you position your car safely. But on R500-million bucket wheel excavators there are seldom any operator-assist features incorporated into the design. This, I couldn’t understand,” he tells MechTech . “At that time, when we asked OEMs such as Liebherr and Caterpillar about helping the operator to look after these machines, the answer that came back was always that the sensor electronics available on the market wasn’t reliable enough for the rough mining environment and that the market could not justify de- velopment investment,” Winkel explains. Based on these observations, research and development towards a monitoring system suitable for these environments began in 2003 at Aachen University in partnership with Ulm University’s Radar Centre of Excellence. “Initially, we tried to use laser technology, but lasers are opti- cal devices that work for one day, then the next day they get dirty and are unreli- able. So we quickly switched to radar.” The feasibility of radar technology was

originally demonstrated in 1904 by the German inventor Christian Hülsmeyer, who used radio waves to detect the pres- ence of ships in dense fog. Describing the benefits of using radio waves as opposed to laser light, Winkel points towards an image showing the effects of dust particles on transmitted laser and radar waves. “The wavelength of a laser beam is around 1.0 µ m, which means that the beam will be fully reflected by a dust particle with a diameter of 2.0 µ m. This prevents laser-based systems from detecting objects behind a dust or fog curtain. Radar operates on much longer wavelengths of around 4.0 mm, resulting in considerably better penetration into fog or airborne dust,” he says. Early investigations into the avail- ability of radar sensors for mining and materials handling equipment revealed that only one-dimensional (1D) level de- tectors were available, which were “never going to give us enough information to control machines in industrial and mining environments,” he suggests. 1. With ThyssenKrupp, indurad’s iCrusher solution was used on a fully mobile crushing systems in China. The quantity and size of material along the full length of the apron feeder is monitored to ensure that the crusher is never empty. 2. An iBelt solution fitted with iDVR belt speed radar (blue), iDRR profile radar (red) and iLDR alignment radar (green). As well as proactively checking belt alignment and slip, this combination allows the material travel speed to be calculated in real time, which can be converted into an instantaneous volumetric flow rate. By taking successive readings, very accurate throughput data can be accumulated. 3. Winkel suggests that the use of indurad radar systems for 3D stockpile management and reclaimer productivity enhancement can improve stockyard productivity by between 5.0 and 10%.

The transfer and hopper cars of a bucket wheel excavator were automated at this coal mine near Aachen. In this application, the loading unit and the transfer car were auto- mated to follow the bucket wheel excavator along the length of the bench conveyor. Inset: A rendered image showing the radar sensing used to keep the transfer and hop- per cars at the required relative speed and position. The Aachen-based research efforts led to the development of a range of robust and accurate radar sensors, with 1D, 2D and 3D capability, and priced between the very sophisticated ‘Milspec’ radar detection systems, costing hundreds of

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Mechanical Technology — February 2015