FA060 Gantry Crane July 14. Ship-to-shore crane for loading containers in port. There is a risk of collision at several points. Source: pixelio.

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1 Avoiding Collisions When it comes to logistics centres such as loading bays and container ports, maximising operational efficiency is a critical factor. Here, efficiencies are characterised by high operational readiness of the facilities and rapid container handling. Typically, logistics centres are 99% operationally ready and so further optimisation and efficiency gains have to come from speeding up the loading and unloading processes. Due to time constraints, the risk of accidents is inevitable. Automatic safety devices constantly monitor the crane systems and prevent them from colliding. But how and where can collision prevention be achieved? Ship-to-shore crane for loading containers in port. There is a risk of collision at several points. Source: pixelio.de Ship-to-shore cranes are used to load and unload container ships whilst in dock. In the Super Post Panamax size, the boom reaches more than 50m on the portside. There is therefore a risk of collision at several points simultaneously. However, due to the size, it is difficult for the crane operator to constantly monitor all potential danger areas. New sensor technology minimises these sources of danger so that the crane operator can focus on the essentials. Page 1 of 6

2 Ship-to-shore crane at C. Steinweg in Rotterdam. The cranes have been fitted with laser distance sensors to prevent collision. Source: C. Steinweg Handelsveem B.V. The distance decides At large dock facilities and loading bays, often several gantry cranes will operate in tandem on a rail system. This means that the crane operator s focus is more on the container at the spreader than on a second gantry crane in the vicinity. There is therefore a high risk of the both cranes colliding. Logistics specialist C. Steinweg Handelsveem B.V. recently eliminated this potential risk at the port in Rotterdam in the Netherlands. If the gantry cranes were to collide, both would have to be repaired, which means that the overall productivity of the shipment centre reduces significantly. For this application, Steinweg relied on measurement technology supplied by sensor specialist Micro-Epsilon from Ortenburg. The optoncdt ILR 1021 sensor used is mounted on the support with the measuring direction pointing towards the next crane with a 30m measuring range. A warning is output if the second gantry crane reaches the Page 2 of 6

3 measuring range of this sensor. In the case of dropping below the 20m mark, further movement of the crane is prevented. The optoncdt ILR 121 sensor operates by using a reflector plate, which is attached to the second crane. The benefit is improved operator safety. If a person passes through the measuring beam or there is heavy rain, the sensor does not detect any measured value and therefore does not emit any interference. The danger is only signalled if the second gantry crane approaches. This sensor solution increases the operational safety and significantly reduces the risk of collision. The optoncdt ILR 1021 sensors operate according to the time of flight measuring principle. A laser diode in the sensor produces short laser pulses that are projected onto the target. The light reflected from the target is recorded by the sensor element. The time of flight of the light pulse to the target and back determines the measurement distance. The integrated electronics in the sensor calculate the distance using the time of flight and condition the signal for analogue and digital output. The dimensions of the cranes require sensors that also measure accurately over long distances. Source: C. Steinweg Handelsveem B.V. Page 3 of 6

4 Height of the spreader For automatic pickup of a container or similar object, it is essential to know the height of the spreader. For this, C. Steinweg uses two optoncdt ILR 1181 laser distance sensors, which measure distances up to 80m without reflector film. The sensors are attached to the trolley and measure onto the hoist. Using the additional information, the current height of the spreader or the scoop is always known. This means that the spreader can either be positioned exactly to the required height, or a transverse movement can be started as soon as possible during the lifting process. The optoncdt ILR 1181 laser distance sensors operate according to the phase comparison principle. The phase comparison principle measures the distance using high frequency modulated Class II laser light. Signals with small amplitude and variable frequency are transmitted to the target. Depending on the distance to the object, the distance changes the phase relationship between transmitted and received signal. A comparison of the emitted with the received laser light therefore enables a statement about the exact distance to the target. Accuracy to < 0.5mm can be achieved with this. It is important that the surface of the target is sufficiently reflective. The integrated heater on the sensor is also useful. As they are used outdoors, the heater switches on automatically at temperatures < 5 C. Misting of the lens is therefore prevented. Collision with the bridge As portal cranes of the ship-to-shore design for loading and unloading ships are equipped with a long boom on the port side, there is a risk of the boom colliding with the bridge of the ship. As well as material damage to boom and bridge, high costs are also incurred due to the downtime of the gantry crane. Therefore, measurement technology is also starting to be used here. The optoncdt ILR 1191 laser distance sensor is suitable for this type of task, whereby a safety zone parallel to the boom is produced. Page 4 of 6

5 The 3D image shows potential applications for laser distance sensors on gantry cranes. Source: Micro-Epsilon Continuous measurements In this application, the focus is on continuous measurement signals rather than the distance to a target. Without a reflector, the ILR 1191 sensor has a measuring range of up to 500m and can measure along the boom into infinity and therefore provide no valid measurements. If the bridge is moved into the safety zone, a reflection of the light pulse occurs. The sensor generates a measured value and the crane movement is stopped. However, thick fog in ports is common, which can result in a measured value being generated and so incorrectly putting the crane out of operation. Alternatively, a reflector is mounted on the end of the boom, which the sensor is aimed at. In normal operation, the sensor provides continuous measurement values. If the value changes due to an impending collision, the crane is automatically stopped. Errors due to seagulls or fog are therefore avoided. The integration of the sensor system can be carried out either during the design phase of the new installation or on existing facilities. Micro-Epsilon s laser distance sensors offer measuring ranges between 0.1m and 3,000m. Using an alignment aid, the sensors can be quickly and easily adjusted to the target. The integrated heater means that the sensor can also perform its task in Winter at very low temperatures. The high operational reliability of the sensor is critical Page 5 of 6

6 for safety-relevant applications such as these. Due to a special protective glass, the sensor lens can be easily wiped clean if it mists up or becomes dirty. The sensors are protected to IP67 for harsh environments. The new ILR Tool set up software also enables fast configuration. Other potential applications include the positioning of the trolley on the crane bridge or the height of the container on the delivery truck. The optoncdt ILR sensors measure distances between 0.1m and 3,000m and are also well suited to outdoor use. Source: Micro-Epsilon Portrait of the author: Dr.-Ing. Alexander Streicher Product Manager for laser distance sensors and confocal sensors at Micro-Epsilon Reprints free of charge, specimen copy requested Text length approx. 7,000 characters including spaces Author: Dr.-Ing. Alexander Streicher Product Manager Sensor Systems Micro-Epsilon Messtechnik GmbH & Co. KG Königbacher Str. 15, Ortenburg Tel.: , Fax: Alexander.streicher@micro-epsilon.de, Page 6 of 6