CYBER PHYSICAL

SYSTEMS

Understand the Features and Components of Cyber Physical

Systems
CPS INTRO
❖ An embedded system consists of hardware and software integrated within a
mechanical or an electrical system designed for a specific purpose.
❖ From watches to cameras to refrigerators, almost every engineered product
today is an embedded system with an integrated microcontroller and software.
The concept of a cyber-physical system is a generalization of embedded
systems.
❖ A cyber-physical system consists of a collection of computing devices
communicating with one another and interacting with the physical world via
sensors and actuators in a feedback loop.
❖ Increasingly, such systems are everywhere, from smart buildings to medical
devices to automobiles.
 EXAMPLE
❖ Consider a team of autonomous mobile robots tasked with the identification and
retrieval of a target inside a house with an unknown floor plan.
❖ To achieve this task, each robot must be equipped with multiple sensors that
collect the relevant information about the physical world.
❖ Examples of on-board sensors include a GPS receiver to track a robot's location,
a camera to take snapshots of its surrounds, and an infrared thermal sensor to
detect the presence of humans.
❖ A key computational problem then is to construct a global map of the house based
on all the data collected, and this requires the robots to exchange information
using wireless links in a coordinated fashion.
❖ The design objectives include safe operation (for instance, a robot should not
bump into obstacles or other robots), mission completion (for example, the target
should be retrieved), and physical stability (for example, each robot should be
stable as a dynamical system).
❖ Construction of the multi-robot system to meet these objectives requires design of
strategies for control, computing, and communication in a synergistic manner.
 REACTIVE COMPUTATION EXAMPLE
❖ Consider a program for a cruise controller in a car.
❖ Such a program receives high-level input commands for turning the cruise
controller on and off and for changing the desired cruising speed. The control
program needs to respond to such inputs by changing its output, which
corresponds to the force that is applied to the engine throttle.
❖ The behavior of such a system then is naturally described by a sequence of
observed inputs and outputs, and the notion of correctness specifies which
input/output sequences correspond to acceptable behaviors.

CONCURRENCY
❖ Synchronous models: components execute in lock-step, and the computation
progresses in a logical sequence of synchronized rounds
❖ Asynchronous models, components execute at independent speeds,
exchanging information by sending and receiving messages.
CONCURRENCY EXAMPLE
❖ In our example of a team of autonomous mobile robots, the robots
themselves are separate entities and are thus executing concurrently.
❖ Each robot has multiple sensors and processors, and computing tasks
such as constructing a map of the environment based on vision data and
motion planning based on the map of the environment can be executing
on separate processors in parallel.
❖ The motion planning task can be subdivided into logically concurrent
subtasks such as local planning to avoid obstacles and global planning for
optimal progress toward the target.
❖ Example for Feedback loop:A cruise controller is constantly monitoring the speed
of the car and adjusts the throttle force so that the speed stays close to the desired
cruising speed
❖ Design of controllers for the physical world requires modeling the dynamics of the
physical quantities: to adjust the throttle force, a cruise controller needs a model of
how the speed of the car changes with time as a function of the throttle force.
❖ Hybrid means a mix of continuous and discrete dynamics
❖ Example for Real Time Computation:For a cruise controller to satisfactorily
control the speed of the car, its design should take into account the time it takes its
subcomponents to execute the necessary computations and communicate the
results.
❖ Applications where the safety of the system has a higher priority over other design
objectives such as performance and development cost are called safety-critical.
❖ The more principled approach to system development involves writing
mathematically precise requirements of the desired system, designing models of
system components along with the environment in which the system is supposed to
operate, and using analysis tools to check that the system model meets the
requirements.
GENERAL STRUCTURE OF A CPS
Internet of Things
(IoT)
 What is IOT?
❖ The Internet of Things is the network of physical objects or "things" embedded
with electronics, software, sensors, and network connectivity, which enables
these objects to collect and exchange data.

❖ It allows objects to be sensed and controlled remotely across existing network

infrastructure, creating opportunities for more direct integration between the
physical world and computer-based systems, and resulting in improved
efficiency, accuracy and economic benefit.

❖ "Things," in the IoT sense, can refer to a wide variety of devices such as heart
monitoring implants, biochip transponders on farm animals, automobiles with
built-in sensors, DNA analysis devices for environmental/food/pathogen
monitoring or field operation devices that assist firefighters in search and rescue
operations.
IoT Ecosystem
 CHARACTERISTICS OF IoT

1. Connectivity

Things of IoT should be connected to the IoT infrastructure. Anyone, anywhere, anytime can
connect, this should be guaranteed at all times.

2. Intelligence and Identity

The extraction of knowledge from the generated data is very important. For example, a sensor
generates data, but that data will only be useful if it is interpreted properly. Each IoT device has a
unique identity. This identification is helpful in tracking the equipment and at times for querying
its status.

3. Scalability

The number of elements connected to the IoT zone is increasing day by day. Hence, an IoT setup
should be capable of handling the massive expansion.
 CHARACTERISTICS OF IoT
4. Dynamic and Self-Adapting (Complexity)

IoT devices should dynamically adapt themselves to changing contexts and scenarios. Assume a
camera meant for surveillance. It should be adaptable to work in different conditions and
different light situations (morning, afternoon, and night).

5. Architecture

IoT Architecture cannot be homogeneous in nature. It should be hybrid, supporting different

manufacturers ‘ products to function in the IoT network.

6. Safety

There is a danger of the sensitive personal details of the users getting compromised when all
his/her devices are connected to the internet. Hence, data security is the major challenge.
 CHARACTERISTICS OF IoT
7. Self Configuring: This is one of the most important characteristics of IoT. IoT devices
are able to upgrade their software in accordance with requirements with a minimum of
user participation.

8. Interoperability: It refers to the ability of different IoT devices and systems to

communicate and exchange data with each other, regardless of the underlying
technology or manufacturer.To achieve interoperability, IoT devices, and systems use
standardized communication protocols and data formats.

9. Embedded Sensors and Actuators: Embedded sensors and actuators are critical
components of the Internet of Things (IoT). They allow IoT devices to interact with
their environment and collect and transmit data.

10. Autonomous operation: Autonomous operation refers to the ability of IoT devices
and systems to operate independently and make decisions without human
intervention.
Internet of Things (IoT) Enabling Technologies
 Internet of Things (IoT) Enabling Technologies
1. Wireless Sensor Network(WSN) :
A WSN comprises distributed devices with sensors which are used to monitor
the environmental and physical conditions. A wireless sensor network
consists of end nodes, routers and coordinators. End nodes have several
sensors attached to them where the data is passed to a coordinator with the
help of routers.
Example –
● Weather monitoring system
● Indoor air quality monitoring system
● Soil moisture monitoring system
● Surveillance system
● Health monitoring system
 Internet of Things (IoT) Enabling Technologies
2. Cloud Computing :

It provides us the means by which we can access applications as utilities over the
internet. Cloud means something which is present in remote locations.

With Cloud computing, users can access any resources from anywhere like
databases, webservers, storage, any device, and any software over the internet.

IaaS (Infrastructure as a service) :-Ex : Web Hosting, Virtual Machine etc.

PaaS (Platform as a service):- Ex : App Cloud, Google app engine
SaaS (Software as a service):- Ex : Google Docs, Gmail, office etc.
The characteristics of cloud computing are:
On demand: The resources in the cloud are available based
on the traffic. If the incoming traffic increases, the cloud
resources scale up accordingly and when the traffic
decreases, the cloud resources scale down accordingly.
Autonomic: The resource provisioning in the cloud happens
with very less to no human intervention. The resources scale
up and scale down automatically.
Scalable: The cloud resources scale up and scale down
based on the demand or traffic. This property of cloud is also
known as elasticity.
Pay-per-use: On contrary to traditional billing, the cloud
resources are billed on pay-per-use basis. You have to pay
only for the resources and time for which you are using those
resources.
Ubiquitous: You can access the cloud resources from
anywhere in the world from any device. All that is needed is
Internet. Using Internet you can access your files, databases
and other resources in the cloud from anywhere.
 Internet of Things (IoT) Enabling Technologies

3. Big Data Analytics :

It refers to the method of studying massive volumes of data or big data. Collection of
data whose volume, velocity or variety is simply too massive and tough to store,
control, process and examine the data using traditional databases.
Big data is gathered from a variety of sources including social network videos, digital
images, sensors and sales transaction records.
Examples –
● Bank transactions
● Data generated by IoT systems for location and tracking of vehicles
● E-commerce and in Big-Basket
● Health and fitness data generated by IoT system such as a fitness bands
 Internet of Things (IoT) Enabling Technologies
4. Communications Protocols :
They are the backbone of IoT systems and enable network connectivity and
linking to applications. Communication protocols allow devices to exchange
data over the network. Multiple protocols often describe different aspects of
a single communication.

5. Embedded Systems :
It is a combination of hardware and software used to perform special tasks.
It includes microcontroller and microprocessor memory, networking units
(Ethernet Wi-Fi adapters), input output units (display keyword etc. ) and
storage devices (flash memory).
It collects the data and sends it to the internet.
CONCEPT OF TRANSDUCERS/SENSORS
Primary and Secondary Transducers
On the basis of the role of the transducing
element, transducers are divided into:

○ Primary transducers are generally the

transducers that respond to external
stimulation and general output for that
signal. The output is generally a change
in any factor affecting the secondary
transducer.
○ Secondary transducers are the ones that
convert the output of the primary
transducer into an electrical signal.
DIFFERENCE BETWEEN ACTIVE AND PASSIVE TRANSDUCER
Active & Passive Sensors:
Active Sensors:
❖ The type of sensors that produces output signal without the help of external
excitation supply.
❖ The own physical properties of the sensor vary with respect to the applied external
effect.
❖ Therefore, it is also called as Self Generating Sensors.
❖ Any sensor which requires to input energy to the environment in order to retrieve
the measurement is active.
❖ Examples: Photovoltaic cells, Thermocouples, Piezoelectric device.
Passive Sensors:
❖ The type of sensors that produces output signal with the help of external
excitation supply.
❖ They need any extra stimulus or voltage.
❖ Sensors are able to retrieve a measurement without actively interacting with the
environment.
❖ Example: Strain Gauge, Magnetometer, Barometer.
Analog & Digital Sensors:

❖ Analog Sensors: The sensor that produces continuous signal with respect to time with
analog output is called as Analog sensors.
❖ The analog output generated is proportional to the measured or the input given to the
system. Generally, analog voltage in the range of 0 to 5 V or current is produced as the
output.
❖ The various physical parameters like temperature, stress, pressure, displacement, etc.
are examples for continuous signals.
❖ Digital Sensors: When data is converted and transmitted digitally, it is called as Digital
sensors.
❖ Digital sensors produce discrete output signals.
❖ Discrete signals will be non- continuous with time and it can be represented in "bits" for
serial transmission and in "bytes" for parallel transmission.
❖ Digital output can be in form of Logic 1 or Logic 0 (ON or OFF). A digital sensor consists
of sensor, cable and a transmitter.
❖ The measured signal is converted into a digital signal inside the sensor itself without
any external component. Cable is used for long distance transmission.
What Exactly Are Actuators?
A device that turns electrical energy into mechanical
energy is known as an actuator. An actuator, in other
terms, is a component that can move or control a
mechanism or system. Actuators are commonly employed
in industrial automation, robotics, and other applications
requiring precise mechanical system control.
Few Examples of Actuators in Internet of Things
Smart Home Systems: Actuators are an important part of smart home systems. They let
customers remotely operate various equipment such as lights, heating systems, and security
systems. A smart thermostat, for example, can use temperature sensors to change the
temperature in a home, and an actuator can activate the heating or cooling system as needed.
Industrial Automation: Actuators are frequently employed in industrial automation to control
machines and other systems. Hydraulic actuators, for example, might be used to control the
movement of robotic arms in a factory, while electric actuators could be used to regulate the
position of a conveyor belt.
Agriculture: Actuators are rapidly being employed to automate numerous processes in
agriculture, such as irrigation and harvesting. An actuator, for example, can control the flow of
water in an irrigation system or the position of a robotic arm used to harvest crops.
Healthcare: Actuators are employed in a variety of healthcare applications, including prostheses
and medical equipment. An actuator, for example, can regulate the movement of a prosthetic
limb or the location of a surgical tool during treatment.
Electrical Actuators
An electric actuator converts electricity into kinetic energy in either a linear (along a straight line), or
rotary (in a circle) motion. The motor of an electric actuator can operate at any voltage, Advantages:
cheap, clean, speedy type of actuator.• Examples: Solenoid based electric bell ringing mechanism

Thermal Actuators
A thermal actuator is a type of non-electric motor. It’s equipped with thermal-sensitive material that’s
capable of producing linear motion in response to temperature changes. Temperature changes can give
rise to such tasks as releasing latches, operating switches, and opening or closing valves. Examples:
Thermal actuator is thermostat,

Mechanical Actuators

Mechanical actuators convert one form of motion into another, they utilize gears, chains, pulleys, rails,
and different contraptions for their operations. They are often combined with another actuator and driving
mechanism. They are used for increasing torque or power of the output or even to convert linear motion
to rotary or vice versa. Examples: Rack and pinion mechanism and Crank shaft
 IoT Stack
❖ Even the most basic IoT devices need a range
of technologies to function.
❖ Sensors, actuators, and computers use
software to transmit data through a network to
another device or application and vice versa.
❖ Collectively, this technology is known as the
IoT stack—and it looks different for every IoT
device.
❖ The IoT stack as the following four layers:
➢ Hardware
➢ Software
➢ Protocols
➢ Cloud
The first layer: hardware
❖ The hardware layer of your IoT stack encompasses the physical components of your
device, such as sensors, mainboards, modules, actuators, SIM cards, antennae, and other
physical pieces.
❖ This layer includes everything built into or attached to your device, as well as any other
physical parts required for the operation of your device, such as modems, IoT routers, and
IoT gateways.
❖ Your hardware governs the kinds of data your device can collect, what it can do with that
data, and to a degree, what firmware and protocols it can utilize.
❖ In IoT, the hardware layer is often intended to last for the lifetime of the device, and the
quality of these components can have a significant impact on your device’s lifespan.
The second layer: device software

❖ The device software layer of your IoT stack includes components such as your device’s
operating system (OS), the application that interacts with your device and its data, and
any firmware needed for your device’s OS to interact with its hardware.
❖ Depending on the hardware and protocols in your IoT stack, some of the tech in this layer
can be upgraded through over-the-air updates. This is vital for closing holes in security
that emerge over time.
The third layer: protocol stack
❖ Protocols are essentially the languages that devices and network entities use to communicate.
❖ The protocol stack defines what kind of data your hardware can transmit and receive, how those transmissions will
be secured (if at all), what kind of network the device will use to communicate, how network entities verify the
accuracy of a transmission, and what your solution will prioritize (such as speed versus accuracy).
❖ Network entities need to use the same protocols to understand each other. Otherwise, their transmissions are like
two humans trying to have a conversation when they don’t speak the same language.
❖ An IoT device won’t always have the data throughput to use the security protocols and other standards your solution
needs, which may make it unable to communicate directly with your application. In these instances, your solution
may use an IoT gateway as an intermediary to “translate” information from one entity into the protocols the other
entity understands. This is common in use cases like smart meter communication.
❖ There may be a regulating body that keeps the protocol up-to-date and ensures it’s standardized globally, or it may
be open source with no enforced universal standard.
❖ Your IoT stack uses protocols at every layer of the network, and the hardware and software that comprise your
solution may rely on different protocols for different interactions and functions. As your hardware and software
changes and your device gains new functionality, your IoT stack may need to incorporate new protocols as well
and/or discard ones that no longer meet your needs.
The fourth layer: the cloud
❖ It’s a combination of scalable, globally accessible data storage, management,
analytics, and utilization solutions.
❖ Whether you fully rely on cloud service providers like Amazon Web Services,
Microsoft Azure, and Google Cloud Platform, or you build some portion of your cloud
solution yourself, “the cloud” enables you to store all of the data from all of your IoT
devices on cloud-based infrastructure, and leverage cloud-based applications to
give your solution advanced capabilities like machine learning and artificial
intelligence.
❖ “Big data” is one of the things that makes IoT solutions so valuable and
effective—and accessibility is another.
❖ The cloud layer of your tech stack is what brings these benefits to your device.
IoT LEVELS
Device :
An IoT device allows identification, remote sensing, monitoring capabilities. Remote
Resource:
• Software components on the IoT device for -accessing, processing and storing sensor information, -controlling
actuators connected to the device. - enabling network access for the device.
Controller Service:
• Controller service is a native service that runs on the device and interacts with the web services.
•It sends data from the device to the web service and receives commands from the application (via web
services) for controlling the device.
Database:
•Database can be either local or in the cloud and stores the data generated by the IoT device.
Web Service:
•Web services serve as a link between the IoT device, application, database and analysis components.
•It can be implemented using HTTP and REST principles (REST service) or using the WebSocket protocol
(WebSocket service).
Analysis Component:
• Analysis Component is responsible for analyzing the IoT data and generating results in a form that is easy for
the user to understand.
Application:
•IoT applications provide an interface that the users can use to control and monitor various aspects of the IoT
system.
•Applications also allow users to view the system status and the processed data.