Cyber-Physical Systems (CPS)

Cyber-Physical Systems (CPS)

CPS are the essence of IoT and IIoT.

Essentially, CPS are physical assets that are able to communicate and share information by using “cyber” technologies.

These cyber-technologies can be grouped as follow:

  • Embedded controllers

    they consist of small computers that allow engineers to add “intelligence” to products at a relatively low cost.

  • Sensors

    A wide range of sensors can be used to monitor systems like accelerometers, gyroscopes, temperature and humidity sensors, pressure sensors, optical sensors and so on.

  • Wireless Technologies

    The most commonly known are Bluetooth, LTE, Wi-Fi.

Cyber Physicl Systems
Figure 2: Technologies used in Cyber-Physical Systems: Sensors, Embedded Controllers, Communication. Source: Special Report: How the Shrinking Cost of Sensors Is Fueling the Internet of Things, Engineering.com. 2018, page 3

IoT combines the “brains” of embedded control, the modularity of smart sensors, and the ubiquitous connectivity of wireless communication.

As a result, the automated manufacturing systems as of today and even more in the future are going to be a composition of software, data, which form a digital twin along with the electronics and mechanical hardware of the physical systems. A full integration of cyber physical systems and availability of a digital twin, i.e. a cyber representation which could be managed in a cyber or physical way, is still a future vision as a number of frontiers of the automation technology as of today need to be overcome.

The following issues have been raised and need attention:

Establishing a communication

Different technologies enable wireless communications, the most common are:

  • Barcodes, QR codes, Data Matrix etc
  • Bluetooth
  • Wi-Fi
  • GSM, LTE, 4G, 5G etc
  • Near Field Communication (NFC)
  • Radio-frequency Identification (RFID)

Position tracking can be also considered a way to interconnect systems, as they provide “info” about their position. In this sense, additional technologies are:

  • Global Positioning System (GPS), used for outdoor tracking
  • Infrared (IR), used for indoor tracking
  • Digital Camera

The adoption of the Internet of Things is driven by the falling cost of smart sensors and the ease with which, as they become ever smaller, they can be deployed into new products.

RFID is probably one of the most widely used technology, due to its simplicity and low cost. In 2014, the world RFID market was worth US$8.89 billion, up from US$7.77 billion in 2013 and US$6.96 billion in 2012. This figure includes tags, readers, and software/services for RFID cards, labels, fobs, and all other form factors. The market value is expected to rise to US$18.68 billion by 2026 (03).

IoT Protocol & Standards

We have already shown how interconnectivity between CPS implies the usage of different technologies (e.g. RFID, GSM, GPS, BLE etc.) each one relying on different protocols and standards. Therefore, it becomes clear how important is to establish the right standard in order that systems can communicate and interact.

Just to make an analogy with human communication, everyone recognizes how useful is to have a common language to speak when we meet people from other countries. This aspect became crucial with globalization. Somehow English has been recognized as a “Lingua Franca”, i.e. as “a common means of communication for speakers of different first languages”

With the same logic, it would be useful to have a “Lingua Franca” to enable system to speak the same language.

The following picture shows and example of current different standards used for different technologies:

IoT Standards
Figure 4: list of different IoT standards. Source: https://www.postscapes.com/internet-of-things-technologies/

IO-Link

Moving back to Industry application, IO-Link standard has been developed to standardize communication with sensors and actuators.

Its objective is to provide a technological platform that enables the development and use of sensors and actuators that can produce and consume enriched sets of data that in turn can be used for economically optimizing industrial automated processes and operations.

An IO-Link system consists of an IO-Link master and one or more IO-Link devices, i.e. Sensors or Actuators. The IO-Link master provides the interface to the higher-level controller (PLC) and controls the communication with the connected IO-Link devices.

An IO-Link master can have one or more IO-Link ports to which only one Device can be connected at a time. This can also be a “hub” which, as a concentrator, enables the connection of classic switching sensors and actuators.

An IO-Link device can be an intelligent sensor, actuator, hub or, due to bidirectional communication, also a mechatronic component, e.g. a gripper or a power supply unit with IO-Link connection.

An example of system architecture is depicted in the following figure:

IO-Link system architecture
Figure 5: IO-Link system architecture. Source: https://io-link.com/en/Technology/what_is_IO-Link.php

IO-link enables transparent, standardized communication between sensors and actuators. Key benefits include:

  • Standardized and reduced wiring
  • Increased data availability
  • Remote configuration and monitoring
  • Extended diagnostics

In the following video from company Banner Engineering additional benefits are described

Manage complexity

The concept of IoT and IIoT is fairly simple: connect devices to improve efficiency and effectiveness. However it is more complex than what it appears. As explained, to develop IoT several hard skills are required. To identify opportunities and areas of implementation, multidisciplinary team are required. Main skills involved are:

  • Mechatronic
  • Electrical
  • Information & Communication Technology
  • Production & process engineering
  • Software Development
  • New Regulation definition

Machine Learning and Artificial Intelligence

In the IoT overview section, one of the main benefits was the enabling of the “data-driven decision making” process. Machine Learning and Artificial Intelligence can be used to take reliable decision (data-driven) in an autonomous way. In section “Artificial Intelligence” have been already shown how AI is important and what current challenges are.

References

03) https://en.wikipedia.org/wiki/Radio-frequency_identification [20/01/2019]

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