The technological and social revolutions of the past few decades have completely reshaped industry. The food packaging and palletizing industry is no exception. In fact, the last ten years alone has seen the adoption of advanced technologies at an unprecedented rate. Here, Alan Spreckley, robotics food and beverage segment manager and palletizing robotics expert at ABB, explains how digitalization is repackaging the future of food palletizing.
The last two decades have seen a decline in the nuclear family and a global rise in the number of private households with only a single occupier. In 2017, the UK office of national statistics (ONS) conducted a study that found 27.8 per cent of UK households had only one inhabitant. Likewise, the labor force survey (LFS) showed that one-third of European households are single person, while the US has been experiencing a significant increase of single person households since the 1920s.
This growing trend places a higher demand for single-portion servings of pre-prepared and pre-packaged food on the food industry, which makes the packaging and palletizing processes less linear than they have previously been. Similarly, the unstable economy of recent years has nurtured a generation of savvy customers, eager for the special offers and deals that retailers regularly provide, further complicating the palletizing process. This leads to scenarios where manufacturers will be required to change palletizing patterns quickly and cost efficiently to deliver this.
Robots have been a staple of the food industry since the 1980s, with most businesses using at least one robotic system for some part of the production line. Palletizing robots have proven particularly popular among plant engineers as they increase productivity, improve working conditions and can be easily integrated into existing production systems.
However, the process of integrating palletizing robots has traditionally relied on computer assisted design (CAD) drawings and involved a lot of estimation.
To quicken this step, virtual commissioning is becoming increasingly popular among plant managers, often using ABB’s innovative suite of virtual commissioning tools. Instead of using CAD, the process is modeled in 3D which provides an accurate visualization of a factory layout. This allows plant engineers to see a digital representation of how the robot will integrate and move within the process and allows them to discover and resolve any potential technical issues before they become a reality, reducing commissioning time by up to 25 per cent.
Motion control looks set to keep running for many years
Industrial control is a highly developed field that advances year on year as the underlying technology advances. But will it and all its specialist sub-sets continue to thrive? Gerard Bush, a motion specialist with INMOCO, offers his opinion.
All technologies develop over time, with most eventually reaching an upper limit where they are as advanced as they can be. This is clearly evident in older technologies where the peak has been reached, an example being steam trains which over about 100 years developed from Stephenson’s Rocket to the Flying Scotsman. In other cases it is less clear. Cars, for instance, continue to develop at a rapid pace. There is no denying that a 10 year old car is not as sophisticated as one fresh off the production line, but it can be argued that the developments are actually advances in constituent technologies rather than fundamental car design – for example, is an engine management system an advance in automotive engineering or electronics applied to automotive applications? Is satnav automotive engineering or digital technology?
Cars are currently offering us another important insight to the advancement of technologies – the role of disruptive change, with the manufacturers responding to socio-political pressures and developing electric propulsion. A Cinderella technology for at least a couple of decades, electric and hybrid cars are now available from most automotive majors and are moving into the mainstream markets.
So is this development pattern being reflected in the world of industrial control? There have certainly been advances since the 1960s days of hand-assembled relay boards and the pneumatic (non-sparking) control of early North Sea oil rigs. Further, it is not surprising that specialist forms of control, such as SCADA, motion control and dual redundancy safety have developed.
There are two main things that drive the advancement of technology. The first is the makers of the technology pushing the performance envelope of their products, to improve performance and give them an edge over their competitors. The second is user demand, people wanting to do more with a given technology and asking the manufacturers to help.
Then we have to allow for the occasional step change caused by a disruptive event, and control technologists are experiencing one right now – Industry 4.0.
The term Industry 4.0 was coined to describe the merger of two separate things in the worlds of manufacturing and production: the field-level device control of automation and the transfer of the resultant data to higher-level control systems for both production and enterprise management. First used in 2011 – at that year’s Hanover Fair – it embraces cyber-physical systems, the Internet of Things, cloud computing, cognitive computing and ‘smart factories’.
In fact it is fair to say that Industry 4.0 is a group of related technologies that are brought together to improve productivity by bringing as much information as possible to the control of machines and processes.
Motion control is now offering an illustration of how this evolving. Over the last few years the developers of motion technologies have improved the data communications and processing capacity of their control units. Naturally, once the controllers had more capacity, users started to set up systems with more information flowing through them. The result is that the host machines have become more responsive to their operating environment and production requirements and thus more productive.
An example of this is that a production machine may be in communication with a system that is measuring user demand in real time (or near-real time) and thus able to automatically react to market changes. Alternatively a machine may be equipped for continuous self-diagnostics, allowing the motion controller to slow down operations and summon maintenance help if a warming bearing is suggesting a possible pending breakdown.
Another example is in the growing popularity of AGVs (automated guided vehicles) in warehouses and factories. These are effectively mobile robots that can travel from workstation to workstation to deliver workpieces, or from storage bin to storage bin to picks parts for an order. The motion control system that drives these units is reacting to live information it is receiving from a central computer – a case of Industry 4.0 in action.
Another way in which motion control is improving is in the precision of its operations. The resolution of positional accuracy has improved steadily over the years and is now at a point where, for instance, precision assembly of small parts is commonplace. With increasing accuracy we see even more innovative applications emerging along with a widening of the areas of use. So today, we see motion control solutions being used for micro-machining, in operating theatres to perform surgeries with supreme accuracy, and to collect individual cells in biological laboratories.
These examples are very exciting, but it is notable that they are each based on the creative use of one or more relatively simple technological developments. Over time these developments will be applied to more and more projects.
As an illustration of a simple but important development, Kollmorgen’s single cable connections for motion systems building makes the physical assembly of systems easier and faster. This takes out cost, improves maintainability and – importantly – encourages widening use of motion control. Similarly, PMD Corp is working on pre-engineered subsystems that can be easily integrated to make large sophisticated systems.
So over the next several years it looks like motion control will be moving into new fields and be more widely used, that industrial control in general will continue to develop becoming more and more capable, easier to use and more widely spread.
The next revolution in motor control
The continued focus on improving energy efficiency and sustainability remains a major driving force for innovation in mechanical and electrical engineering arenas. Improved speed control using variable speed drives (VSDs) has produced significant energy savings, but the next step needs to be much bolder – the implementation of a direct current (DC) grid within industrial premises has the potential to reduce operating costs and take advantage of renewable energy sources.
The German Electrical and Electronic Manufacturer’s Association [Zentralverband Elektrotechnik und Electronikindustie (ZVEI)] initiated the DC-INDUSTRIE research project along with 21 industrial companies and four research institutes. Together they are jointly working on the project to implement the energy transition in industrial production and, therefore, bring more energy efficiency and energy flexibility into industrial production.
Among those involved is Bauer Gear Motor, which is part of the Altra Industrial Motion Corporation, and Karl-Peter Simon, Bauer’s Managing Director, who is taking a leading role in the research.
Karl-Peter Simon: “This research project has the potential to benefit a large number of manufacturing industries, with one large automotive company already planning to implement some of the recommendations in a new test facility. Bauer is keen to use its expertise to help deliver this innovative vision and make a significant contribution to improving energy efficiency.”
In the industrial sector, electric motors account for about 70% of electricity consumption and are thus the most significant load of electrical energy. Reducing the energy requirements of these drive systems by increasing their efficiency contributes to an equivalent reduction in CO2 emissions.
Since January 1, 2017, all new 3-phase motors sold in Europe with rated power from 0.75 to 375 kW must conform to energy efficiency class IE3, or alternatively, IE2 for use in frequency inverter operation. These efficiency classes are specified for three-phase asynchronous motors operating at nominal speed and nominal torque. However, experience has shown that an energy efficiency regulation of a component can only sustainably reduce energy in certain operating modes.
With this in mind, the DC-INDUSTRIE project, by means of direct current networks, aims to support both the energy transition and energy efficiency, as well as Industry 4.0. The project is sponsored by the Federal Ministry for Economic Affairs and Energy [Bundesministerium für Wirtschaft und Energie (BMWi)] and has a term of three years.
Inefficiencies in speed control
The advantage of using a frequency inverter is the continuous adaptation of the motor speed to the actual need, which can very often also lead to energy savings. A frequency inverter is supplied with the alternating current, which is first converted into direct current using a rectifier. The direct current is then converted into alternating current with variable frequency and voltage through a voltage feed inverter in order to electronically change the speed of a three-phase motor.
However, if the three-phase motor is operating in the braking mode, e.g. in a crane that is in lowering mode, the energy flow changes. But, this energy cannot be fed back into the grid by the frequency inverter because the input rectifier only allows the energy to flow in one direction. Therefore, the energy that is fed back must be dissipated via the direct current voltage circuit of the frequency inverter.
For this purpose, a brake chopper is connected to the intermediate circuit. This monitors the intermediate circuit voltage with regard to the voltage level. If the intermediate circuit voltage exceeds a set threshold value, the brake chopper switches the braking resistor between the positive and the negative pole of the intermediate circuit. This is usually an additional external braking resistor that converts the braking energy into heat energy.
Reducing harmonics issues
The increasing use of frequency inverters to control motor speeds has led to problems with mains effects, causing harmonics and distorting the voltage. There is no standard solution for harmonics, since each grid and its electrical load are very different. Ultimately, the operator is responsible for the voltage quality of its own production facilities. If frequency inverters or other devices with power electronics are increasingly installed, grid effects will increase.
The challenges presented show that a further increase in the use of inverters for the flexible control of electric motors is desirable and very often even necessary. This is the only way to improve both production processes and energy efficiency. However, line perturbation due to harmonics and equipment costs limit the increase.
In order to achieve significant progress in energy efficiency and system cost optimization, new approaches are needed. To enable energy efficiency, energy transition and Industry 4.0, new grid structures are required.
Creating the solution
The new network structure is based on an alternating current supply, which provides the direct current power supply for production plants via a central rectifier. Active grid filters are integrated into the central rectifier to ensure the voltage quality harmonic requirements.
The direct supply of the frequency inverter with direct current means that all decentralized energy conversion is no longer needed. Since central energy conversion (from AC to DC) is significantly more efficient, conversion losses are significantly reduced.
Through the direct supply of all electric motors via a frequency inverter with direct current power supply, all installed motors are connected via a common direct current voltage grid. Furthermore, a direct current voltage network essentially only causes ohmic transmission losses. Compared to an alternating voltage network, the capacitive and inductive line losses are eliminated.
In addition, the central direct current voltage network offers the possibility of integrating photovoltaics directly at the direct current voltage level. In this case also, conversion from DC to AC is not required to be done by an inverter. This grid infrastructure offers the possibility of optimizing the purchase of energy and to stabilize the grid.
Through the elimination of the input rectifier and the grid filter with frequency inverters, these can be designed more cost-effectively and more compactly. This simplifies integration into the motor, which can significantly increase the degree of acceptance. Variable speed motors allow for a reduction in variants and energy savings. They provide status signals from all DC-fed drivers, which are of great importance for flexible and safe production control.
Grid management makes it possible to optimize operational management in terms of energy costs. The accessible information enables preventive production control measures to significantly increase the availability of production. This is a prerequisite for the successful implementation of Industry 4.0.
Where the robots come from?
Collaborative robots were a big feature of the Hannover Messe trade show again in 2018. Small, intelligent, sensitive, and self-learning: The ways in which robots can be used are increasing all the time. And the level of acceptance is also rising – not least thanks to attractive prices and short ROI times. Off-the-shelf handling solutions are in demand and Yuanda Robotics has a range of market-ready robot systems. For its drive technology, this young company from Hannover depends on the robotics expertise of KOLLMORGEN.
You know about our horses, now find out where the power comes from! With slogans like this, Lower Saxony is confidently advertising its own innovative strength – something which is most apparent in its robotics expertise. The region’s claims to market leadership were once again made clear at the Hannover Messe 2018 – not least in the shape of start-up company Yuanda Robotics. Founded just over one year ago, the company exhibited a number of robots for performing various load-carrying tasks. Inside, they are powered by specially customized servo motors from KOLLMORGEN’s KBM range. What is remarkable about these is that the powerful synchronous machines are frameless and can be embedded in the construction of the robot straight from the kit. The main advantages of this are that it saves space, and heat can be extracted far more efficiently.
Dr. Jens Kotlarski likes to lead his new robots by the hand. “In the same way as I would show things to my child, I show them to the machine,” says the managing director of Yuanda Robotics GmbH – a successful spin-off set up by three scientists from the Leibniz University in Hannover with funding from the Shenyang Yuanda Aluminium Industry Group in China. The company from Hannover is aiming to successfully bring different types, such as the L.3, M.3 and M.6 versions which, they exhibited, to market by the end of the year. The robots are designed to act as automated handling assistants for manual assembly lines in industry. “That’s why our robots have a similar reach to the human arm,” explains Kotlarski. “Humans are not really able to move loads of 5 kg or more ergonomically for long periods – especially if the parts also have to be lifted from low down to high up”.
For example, one specific area of use for the new robots from Hannover would be the loading of machines. Insert the component, press the button, wait, remove the component, and put it in a box – all day long. These are monotonous tasks that are avoidable. Kotlarski believes that people can be used far more cost-effectively in other ways. Before setting up Yuanda Robotics, he worked as a group leader at the Institute of Mechatronic Systems at Leibniz University in Hannover. The first “Made in Hannover” robots are principally designed to serve as production assistants for continuous operation. Among other things, using them in this way raises the question of how the heat from the drive technology can be most effectively dissipated.
High power density
This is where the frameless structure of the KOLLMORGEN KBM motors can improve heat extraction simply by convection across the robot’s joints. The effect of these excellent thermal properties is that the KBM motors can reach peak performance without derating. “The high power and performance density were important reasons why we used these motors,” explains co-founder Matthias Dagen. Small motors with a high output are essential if the arms and the joints are to be made as compact as possible. “The thinner and more lightweight the design, the heavier the loads that the robot will later be able to carry,” explains Dagen. Overall, it improves inertia behaviour and the ratio between the robot’s own weight and the weight it can carry.
Nevertheless, the requirement for lightweight construction has its limitations because a certain surface area and mass are needed in order to dissipate the heat effectively. But this is where the KBM motor assemblies from KOLLMORGEN prove to have particularly robust thermal properties. The stator winding has been defined by the specialists in servo drive technology and motion control as having continuous capability at an internal winding temperature of up to 155°C. Aspects such as this were crucial criteria when the motors from the KBM range were being designed and dimensioned. There was close cooperation on the engineering between Yuanda Robotics and KOLLMORGEN – mainly in the person of KOLLMORGEN project manager Markus Grohnert. “Having a personal contact was also important to us when we were choosing the most suitable drive manufacturer,” emphasizes Matthias Dagen. In addition to the strict performance criteria, delivery times for the components were another key factor for the young start-up company. “We need to be able to rely on short timeframes, if we are aiming to bring new products to market quickly,” says Dr. Jens Kotlarski.
Quick delivery for quick start-ups
The short delivery times for the frameless motors in the KBM series are mainly possible because each bespoke drive system is the result of a clever combination of standard components. Refinements can be made, for example, to the rotor hub dimensions, stack length, diameter, assembly jigs, windings, connection type, and much more. Part of the work of the engineering project at Yuanda Robotics consisted of Markus Grohnert making sure that the direct drive was perfectly matched to the intended robot gear system.
When it comes to control units, by the way, despite the ready availability of products that have been tried and tested in industry, Yuanda Robotics relies on in-house development. “We are aiming for a highly integrated solution that can’t be achieved with standard control units – in terms of function or price,” explains Matthias Dagen. The main reason for this is the special algorithms which are supplied to the control unit. Dr. Jens Kotlarski: “To do that, we have to go deep into the control technology and we want to eliminate all the superfluous functions that standard control units inevitably bring with them.” The two men are happy that they are able to bring to market a solution that has been deliberately reduced to the essentials. Both are in agreement: “KOLLMORGEN’s experience with frameless direct drive motors made them perfect partners for us in this kind of robotics work, including on the electromechanics.”
The bottom line
With their new series of robots, the company from Hannover is marketing a solution that provides everything that is needed to automate assembly and handling tasks quickly and reliably. The overall package is nicely rounded off by the integrated camera technology in the robot. This enables the robot to identify the products it needs to pick up by itself. For the visualization, the company has taken advantage of the potential of so-called augmented reality. This means that, when the parameters for new tasks are being set, the movements of the robot in the workspace can be exactly simulated – and then they can be sent out to start production. Helping people to understand these complex systems is one of the main objectives for Yuanda Robotics, in the hope of further increasing the acceptance of robots.
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