Who’s in control here?30 November 2021
Technology now offers crane control systems that can do all that skilled operators can do but more smoothly, more efficiently and more safely. Julian Champkin investigates.
A skilled crane operator can lift his load vertically from the floor, so as not to drag it; can move his load from A to B without it swaying; can stop if an obstruction or a person gets dangerously close; can avoid hitting the walls, or any other crane on the same runway; can slow his load as it nears its destination, inch it into position, and lower it accurately, gently, and precisely where it is needed. But even the most skilled operator, with years of experience behind him, can do these things more easily, more reliably – and above all, more safely – if his crane is fitted with automated control systems for vertical lift, anti-sway, safety zoning, inching, and set-down; which is why these automated control technologies are now routinely offered on factory hoists and cranes.
Casey Cummins, controls product manager for Magnetek, (part of Columbus McKinnon) takes us through the basics of fitting automated crane controls.
“The very first priority for customers is usually safety,” he says. “When installing new or updating existing cranes, customers not only look to improve the control of the crane but also look for ways to increase operator and employee safety.
“Automation is a huge advance here, since it helps get people away from the equipment. If anything does go wrong, you can always fix equipment, but you can’t say the same about people.
“When automating any crane system, there are a couple of areas to consider. The first is cost, establishing a budget and understanding the value of the investment. As customers look to automate cranes, technology continues to advance to provide more options while driving costs lower. Additional improvements can include radios, variable frequency drives, safety controls, motors, and programmable logic controllers (PLC).”
The automotive industry has driven several designs for sensors and safety. Years ago, safety features and sensors were options for cars. Today, many of them are included as standard and may even be mandatory. There has been a large investment in the research and development of sensors, together with high-volume production, which brings down costs. The crane industry is no different, and we have been developing new products, sensors, software for almost 50 years. So, when thinking of improvements to the crane controls to improve functionality, reduce product waste, increase throughput, or employee safety, the initial costs may be significant, but they will come with a quick return on investment, explains Cummins.
One option for cranes is our collision avoidance technology. “It is pretty surprising that only 10% of overhead cranes currently have collision avoidance fitted. This is something that is inexpensive and easy to integrate, and it can save customers from having expensive repairs from cranes colliding with each other or a wall. In addition to avoiding cranes, there is technology such as Intelli-Protect No Fly Zone systems that create barriers around objects on the plant floor, such as assembly lines with employees, racks or storage equipment, or other pieces of equipment that the crane needs to avoid.
“This kind of automation relies on sensors; and the sensors you will use depend on your environment. In typical indoor applications where you don’t have dust, you can mount a low-cost laser that points to a reflector on your wall or on the other crane and measures the distance to an object or wall and tells you how far away it is. So, if you want to stop 10 feet before a potential collision point, this technology can automatically stop the crane and prevent that accident.
“If you are outdoors, the sun can interfere with lasers; or in steel mills you often cannot see more than 20 feet in front of you. For those applications, you would use a higher-end technology such as a radar. Again, the automotive industry has helped there: Automotive manufacturers will use radar on vehicles to ‘see’ through all sorts of bad environments, like fog,” adds Cummins.
Crane sensors and technology do the same thing. “The sensors provide feedback to tell you where your hook is or your trolley. Then, you can add some additional intelligence. Other sensors - cameras perhaps - spot where the load is, so your crane can pick it up automatically. While you may only have a hook on the end of the hoisting rope coming down to the plant floor to lift the load, there may be additional sensors on it that are weight or pressure driven. These sensors give you feedback that it has successfully latched onto something. From there, you can have the crane move the load from point A to B to C automatically if it is a fully automated crane or with the push of a button from an operator in a semi-automated system.
Crane controls today can also integrate with the business systems of the entire factory, linked in with the supply chain, the stock inventory, the customer demand data, and so on. For example, the crane could ‘know’ from that data how many units to deliver to the red paint shop and how many to the blue and could work out the most efficient order or route of doing it. How far you go down that road depends a lot on what areas is the most critical at the time of investment. The best part about automating a crane is that you do not have to do it all at once. You can budget and plan out different modifications and upgrades over months, quarterly, or years.
“Installing this technology is getting a lot easier and simpler. It is getting to the point where the customer or end user can set it all up themselves. On some of the newer automation systems, there is a predefined logic on your crane, and you log into it with your cell phone or tablet and set it all up remotely. So, for example, if you have an office in the middle of the facility floor, you can use your phone to tell the crane ‘Here are the four corners of this office, don’t ever go there’. And it is easy to alter if you change your plant floor layout as well.
“If you have been in the industry for two or three decades you may find it amazing that you can set up and maintain a crane from your phone. If you are a 20-something just entering the industry, you grew up with smartphones and video games and it would blow your mind if you couldn’t log in to the crane from your phone. This generational shift helps with adopting the technology, and it helps with attracting young people to the crane industry as well, which is nice.,” adds Cummins.
“Magnetek has a product called Intelli- Connect which does exactly that. It uses a Wi-Fi signal on the variable-frequency drive of your crane, which is usually 20 to 100 feet up in the air, and you can log into it with your phone or tablet and monitor or configure your drives from down on the floor. So, if you need to change anything, you don’t have to climb up there, and you don’t have to take your crane out of commission just to change one parameter – which is the main premise of Intelli- Connect.
“Another important safety control is vertical lift or off-centre pick prevention. If the hook is not directly above the load when it starts to lift, it will drag the load sideways along the ground, which will cause it to swing dangerously. Again, this development came from the automotive industry. They came to us and said ‘Hey, a lot of people are being injured every year because they’re lifting these heavy dyes for stamping car parts, and they lift them at an angle because they’re in a hurry or cannot align the hook and the load.
“These heavy loads can swing and sometimes it hits somebody or something. What can we do to prevent it?”
“So, we put a sensor on the rope to make sure that it is centred before we allow a lift to take place. It is an easy and inexpensive solution that gives true vertical lifts with no swaying from the start.”
Control systems can be programmed. Or, better, they can be taught to learn. The difference is profound. “The next era of automation is intelligence,” says Darragh Staunton, president and COO of PaR Systems, headquartered in Minnesota.
“Over the last decade automation has become a term that encompasses a lot but means very little,” he says. “Automation has essentially become a catch-all term for pre-programmed tasks done by a machine or robot. We tell machines what to do and they do it efficiently and at scale. But what if machines could be taught to do more, learning from mistakes and figuring out how to improve processes without human intervention? That new era of intelligent automation is possible today and is being driven by technologies that, many times, sit outside traditional automation investment.”
PaR produce, among other products, ‘Expert Operator’ crane controls. Expert Operator is a hardware module that intercepts pendent commands from the operator and converts them into expert commands – and then issues the modified commands to motor drives. “This permits all crane operators to perform like experts. Cable sway is eliminated; efficiency and safety are increased.” PaR says that with it both novice and expert crane operators can reduce payload swing by 85-95%.
Control systems are about much more than up-down and forward and back movement of the hook. Many of Konecranes’ overhead hoists and gantries find applications in warehouses; and their Agilon digital system controls not just the movements of the hoists but the entire warehouse distribution as well as the stocking records.
’Konecranes Agilon is an automated warehouse that can retrieve and store up to thousands of tools, packages, components and spare parts. It keeps a full record of every transaction and provides real-time information about the stock balance of each material.
In practice the operator simply places the package onto the nearest Agilon access point, the system records a weight and picture of the package, an operator confirms the item and stock balance information, and Agilon will take care of the rest by delivering it to a suitable spot.
It can store and handle plastic or carton board packages, tools and components up to 60cm x 40cm x 45cm in size and up to 25kg in weight.’
Demag, an equally big name in gantry cranes, has traditionally offered operator-controlled or automated options for controlling process cranes.
It recently introduced what it is calling a third option, a Remote Operating System (ROS), launched at the end of last year.
The ROS can be in an office, near the crane, or somewhere completely off-site. It is in effect a virtual cab, which is operating a crane in real time.
“For decades the best position to operate an overhead travelling crane (OTC) was from the crane bridge: that was where the operator had the best overview. But the position may be noisy, dusty, cramped, and subject to vibration. So in many applications, radio control has become established,” says Christoph Kreutzenbeck, Demag’s senior manager of global marketing. “For manually controlled cranes in aggressive environments, such as waste incineration plants, control stations can be installed in glass-fronted cabins overlooking the area of operation.” Now though, with the Demag Remote Operating Station the crane operator can be in a comfortable office away from the hazards and discomforts of the site.
“By decoupling the crane system from the operator station, the safety of crane operators can be further increased and on-site costs can be minimised,” says Kreutzenbeck.
“In simple terms, the ROS is a complete, location-independent operating station for cranes. The operator has access to all the control elements that are normally installed in a crane cab. With ROS, however, the owner can decide where the “virtual” cab is going to be located.
“In addition to the usual joysticks, a touch panel or a tablet can be used as a human-machine interface, via which the operator can call up additional information.
“A widescreen monitor provides a view of the process, receiving real-time images from several cameras. The screen layout can have up to eight individual images; a dashboard with process-relevant information can be displayed in the lower part of the screen. Speakers integrated into the monitor make the operating environment even more realistic - the operator receives acoustic feedback from the process, which supports him or her in operating the system and enables a better assessment of whatever is going on.
“The Demag ROS offers the operator an even better view than a conventional crane cab. This is because the cameras can also “look” where the normal field of vision would be restricted.
Zoom functions can give close up views that would otherwise be impossible conventionally. And the possibility of saving screenshots or digital videos and making them available to third parties makes it easier for example to train staff, or to analyse efficiencies in operation.”
Typical applications, he says, would be in bulk material cranes, waste recycling, or feeding of incineration lines. “It can be a virtual crane cab for cranes that operate in unfavourable ambient conditions.
“Experience has shown that this new type of remote crane control not only increases crane productivity and reduces costs. Cranes operated by ROS also operate with a very high level of safety and low risk of damage because the operator always has the best view of the process and can work in an ergonomic and comfortable environment.”
Sway control and anti-collision devices are not confined to the fairly light loads typical of the automotive industry. In heavy industry they are if anything more vital. Stefan Dahlman manages the international sales of Swedish manufacturer Gigasense.
“We normally work within the heavy duty industry; our products are developed to meet conditions when it is hot and dirty” he says. That is where the safety requirements, like the environments, are extreme. “We are talking of loads of 300 or 400 metric tonnes – full buckets of molten metal for example; so very high levels of safety are required.
“Laser distance-sensors can work in such environments, but they need frequent maintenance and in these situations reliability is everything. A shut-down in a steel plant in Europe can easily cost €100,000 euros an hour. In the US I am told it can be ten times that amount. So operators require absolute reliability.
“We have a microwave anti-collision system that works in these very dirty environments, and it is maintenance-free. Also, it has a safety feature that many competing systems lack. The unit on one crane sends out, say a 10Ghz signal – the frequency varies in different countries.
“Most systems simply listen to the echo from the other crane to work out how far away it is. But the echo could be from any metallic object that happens to be in the way, so you cannot be certain that the distance you are measuring is actually the crane-to-crane one,” adds Dahlman.
“In the Gigasense system a unit on the second crane modulates the echo with 16 kHz, then the first unit recognizes the signal as a “fingerprint echo”. That way you can be sure that it is actually the signal from that second unit, not a stray reflection, that the first unit is hearing.”
Gigasense also makes overload protection systems. for its customers.
“The sensor can be a wire rope mounted transmitter that works by measuring the deflection of the rope as it straightens under load; they are very easy to fit, installation time is also important for our customers,” explains Dahlman, “We strive to make sure our products plug & play as much as possible..”
The overload protection system can be linked to an angle-measuring sensor, and in that way you can combine the load sensor and the angle sensor, in this way, a side pull protection function is achieved to protect the crane from wire rope wear.
“All these devices work automatically, in the background; the aim is to ease the operator’s task, not to overburden him with information.
“The overload protection system will stop the lifting action of the crane if it is overloaded, or the anti-collision system will slow the crane if it gets near the opposite crane or wall, and then stop it if it gets too close,” he says.