Insight

Automation Spreads Its Wings

28 Apr , 2017  

Automation is the use of control systems, such as computers or robots, and information technologies for handling different processes and machineries automatically. One key objective is to replace human labour content (wages and benefits), and thereby reduce cost – automated systems can work 24 hours a day. Although installing industrial automation is associated with a high initial cost, the labour savings allied to low maintenance costs makes it a compelling financial case. If it fails, only computer and maintenance engineers are required to repair it.

Automation systems are not limited to manufacturing. Examples are seen in everyday life through ticket machines at railway stations replacing booking clerks, driverless trains and automatic pilots on passenger aircraft.

In an industrial context, the focus of automation has shifted to increasing quality in a manufacturing process. In the automobile industry, for example, the installation of pistons into the engine used to be performed manually with an error rate of 1-1.5%. Presently, this task is performed using automated machinery with an error rate of 0.00001%.

A third factor is the flexibility that automated systems can bring to manufacturing. Traditionally, we look at automation as a means of making high volume manufacturing processes more efficient. But one of the consequences of increasing manufacturing automation is greater flexibility of production lines to be able to produce smaller and smaller batches of product with minimal changeover times. In the pharmaceutical and automotive industries, this is being taken to the ultimate level of a batch size of one, known as personalisation. Here, each series of medicines, or each vehicle, is customised to the specific requirements of a single customer. We talk about product personalisation more here.

Automation in industry

Despite all these benefits, installing automation systems comes at a cost which is more than the upfront capital cost. Substantial costs may be involved in training employees to handle this new sophisticated equipment. Also, the more efficient the automated system, the more crucial the human contribution of the operators if something does go wrong – humans are less involved, but their involvement becomes more critical. If an automated system has an error, it will multiply that error until it is fixed or shut down. This is known as the Paradox of Automation. A fatal example of this was Air France Flight 447, where a failure of automation put the pilots into a manual situation they were not prepared for.

Automation has also hit the headlines recently for social reasons. The issue of what to do with large numbers of displaced workers continues to tax the political establishment, as they seek to grapple with the issue of inequality. Compensation in the form of a Universal Basic Income (UBI) is being trialled in Finland and elsewhere.

Digitalisation

Adding automated data collection allows plants to collect key production information, improve data accuracy, and reduce data collection costs. This provides the ability to measure the effectiveness of the plant and inform decisions for reducing waste and improving the process.

Based on data received from remote stations, automated or operator-driven supervisory commands can be pushed to remote station control devices, which are often referred to as field devices. These control local operations such as opening and closing valves and breakers, collecting data from sensor systems, and monitoring the local environment for alarm conditions.

Automation spreads its wings

Collaborative robots (Cobots)

In recent years, collaborative robots (Cobots) have emerged: in contrast to traditional robots, which cannot operate in an operator-occupied workspace without safety fencing, these cage-free robots can work side by side with humans on shared or separate tasks.

Although collaborative robots do not eliminate the need for workplace risk assessments, the increased adoption of peripheral safety devices is enabling robots and humans to work in close proximity of each other, eradicating the fear of interrupting production or worse, an accident.

Cobots are equipped with force sensing to limit their power and force: in any situation they can feel or detect an abnormal force and stop their motion immediately. Although they still cannot avoid a crash, Cobots can reduce its impact and avoid certain types of incidents, like crushing accidents. This makes them safer to work alongside humans.

Cobots are not a direct replacement for conventional robots, which means that the ROI equation will be different. They typically cost a fraction of their traditional counterparts and boast payback periods in months rather than years. They require very few external devices to work properly, but they also lack some of the capabilities of traditional robots, especially when it comes to heavier payloads and faster cycle times. They also do not directly replace the human labour which is intended to work alongside it.

Automation in agriculture

From farm to fork

Although the takeup of automated systems in the food and beverage sector industry has been relatively slow, it is now accelerating, driven by product traceability. Following the lead of the pharmaceutical industry, which has many standards and guidelines that need to be followed, standards are steadily being adopted for identifying items, locations, shipments, assets and associated information, as well as enabling data to be shared between the different parties in the supply chain.

Today, serialisation codes are a defined process step which makes it possible to track and trace products from the beginning of a process through to the end. In the near future, serialisation codes will be used to make it possible to track and trace the products made for an individual consumer. Customisation is getting easier to achieve and manufacturers will use automation to know how and when to schedule their process to produce goods on time and deliver them to the right address.

Meanwhile, at the other end of the food chain, agricultural vehicles have been at the forefront of developing and adopting autonomous navigation technology. Indeed, more than 320,000 tractors equipped with auto-steer or tractor guidance were sold in 2016 alone, expected to rise to 660,000 in 2026. These tractors use RTK GPS technology to autonomously follow pre-planned paths with centimetre-level accuracy. This makes agriculture the largest adopter of autonomous navigation.

Leading tractor companies worldwide have already demonstrated master-slave or ‘follow-me’ unmanned autonomous tractors or load carts. In these arrangements, a manned operator supervises the movement of the leader tractor with others following suit.

In practice, this has translated into ever larger and more powerful agricultural machinery for use in large-scale crop field farming. Fully and unmanned autonomous tractors will be the next evolutionary step. Multiple semi-commercial prototypes have already been demonstrated by leading agricultural machinery companies.

The technical challenges are largely resolved. Here, the tractor becomes equipped with a variety of overlapping sensors such as LIDAR, RADAR, and sonar to provide autonomous navigation in the absence of GPS signal together with collision avoidance.

Technology costs are currently high but the largest hurdles are to be found in the lagging regulatory framework and the farmers’ desire to stay in charge. These will all inevitably change, particularly as the farming population further ages across the globe.

Mnufacturing Automation

Manufacturing automation

Industrial automation deals primarily with the automation of manufacturing, quality control and material handling processes. Machines vary hugely in size and scope. At one end, automation machines are mass produced, such as those which undertake pick-and-place operations and wave soldering for printed circuit boards (PCBs). These are used for high speed, high precision placing of broad range of electronic components, like capacitors, resistors, integrated circuits onto the PCBs which are in turn used in computers, consumer electronics as well as industrial, medical, automotive, military and telecommunications equipment.

At the other end of the scale, a dedicated production line or machine may be built for a specific purpose by a specialist systems integrator or machine builder. Such companies often specialise in particular market sectors or types of machine, and often have established relationships with one or more component suppliers.

Industrial automation is to replace the decision making of humans and manual command-response activities with the use of mechanized equipment and logical programming commands. Industrial control systems encompass several variants, including supervisory control and data acquisition (SCADA) systems, distributed control systems (DCS), and other smaller control system configurations, such as programmable logic controllers (PLC).

Programmable logic controllers (PLCs) are a type of special purpose microprocessor that replaced many hardware components such as timers and drum sequencers used in relay logic type systems. General purpose process control computers have increasingly replaced standalone controllers, with a single computer able to perform the operations of hundreds of controllers. Process control computers can process data from a network of PLCs, instruments and controllers in order to implement typical (such as PID) control of many individual variables. They can also analyse data and create real time graphical displays for operators and run reports for operators, engineers and management.

Process control computers process data from a network of PLCs

Complicated systems, such as those in modern factories, planes and ships typically use a combination of mechanical, hydraulic, pneumatic, electrical, electronic devices and computers, usually in combination.

An advanced type of automation that has revolutionised manufacturing, aircraft, communications and other industries, is feedback control, which is usually continuous and involves taking measurements using a sensor and making calculated adjustments to keep the measured variable within a set range. A key trend is increased use of machine vision to provide automatic inspection and robot guidance functions. The energy efficiency of such components as motor controls, general purpose pumps and fans has also become a higher priority.

Electric motors that drive industrial machines need some means of control. Matching the correct drive to the type of motor in an application is critical for getting the best fit for torque, speed, and efficiency. There are a wide range of drives available depending on the needs of the specific application and motor type. In general though, drive types typically fall into two categories – DC and AC drives.

And at its most basic level, a motor drive controls the speed of the motor. The drive is the electrical components that make up the variable frequency inverter itself, the interface between the control signals and the motor and includes power electronic devices such as SCRs (silicon controlled rectifiers), transistors, and thyristors.

AC drives control AC motors, such as induction motors. These drives are sometimes known as variable frequency drives or inverters. AC drives convert AC to DC and then using a range of different switching techniques generate variable voltage and frequency outputs to drive the motor.

A basic DC drive is similar in operation in that the drive controls the speed of a DC motor. A common method is a thyristor-based control circuit. These circuits consist of a thyristor bridge circuit that rectifies AC into DC for the motor armature. Varying the voltage to the armature controls the motor speed.

Another powerful kind of drive function is known as regenerative (regen) braking. This is a way of stopping a motor’s rotation by using the same solid-state components that control the motor’s voltage. The energy generated from braking can be channelled back into the AC mains or into filter capacitors. The motor can be in either forward or reverse direction without having to physically switch the polarity of the motor leads and without the need for reversing contactors or switches.

The demarcation behind drives and PLCs is becoming – to some extent at least – a little blurred. Drives can take over some of the traditional functions of a PLC and with components distributed around an open network, elements of any system can be controlled locally and remotely.

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Andy Pye

Andy Pye

Andy Pye has been an editor and technical writer serving UK manufacturing industry for nearly 40 years. He is currently Managing Editor of Controls, Drives and Automation and editor of Environmental Engineering, two leading bimonthly titles. Andy is a Cambridge University graduate in Materials Engineering. In the 1970s, prior to entering the technical publishing industry, he worked for a consultancy organisation where he became an international authority on asbestos substitution and edited a major materials selection system for engineers.