Unit 1

Industrial Automation
Automation is generally defined as the process of enabling machines to follow a predetermined sequence of
operations with little or no human intervention and using specialized equipment and devices that perform and
control manufacturing processes and operations.

OR

It is defined as automatically controlled operation of an apparatus, process or system by mechanical or

electronic devices that replaces human observation, effort and decision.

Need/ reasons for Automation

1. Automation generally has the following primary goals:
2. Integrate various aspects of manufacturing operations so as to improve product quality and
uniformity, minimize cycle times and effort, and reduce labor costs.
3. Improve productivity by reducing manufacturing costs through better control of production. Parts are
loaded, fed, and unloaded on machines more efficiently, machines ate used more effectively, and
production is organized more efficiently.
4. Improve quality by using more repeatable processes.
5. Reduce human involvement, boredom, and thus the possibility of human error.
6. Reduce work piece damage caused by the manual handling of parts.
7. Raise the level of safety for personnel, especially under hazardous working conditions.
8. Economize on floor space in the plant by arranging machines, material handling and movement, and
auxiliary equipment more efficiently.

Advantages of automation
1. Increased productivity
2. Reduce the labor and skilled workers
3. Provides safety to workers and reduce accidents.
4. Reduced scrap and wastages and thus saving material cost.
5. Reduced manufacturing lead time ( time between customer order and product delivery)
6. Reduced in-process inventory by reducing the time a work part spends in the factory.
7. Consistent product quality.
8. Lower product price and better products.
9. Automation increases standard of living.
10. Lesser floor space
11. Machining of advanced materials can be easily done

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Disadvantages of Automation
1. It reduces the labour force especially skilled employees, which reduces employment opportunity.
Automation may treat the human as a machine
2. It reduces the purchasing power since the market is saturated with products that the people cannot
afford to purchase.
3. Initial investment is very high
4. Setting time of machine takes more
5. Breakdown or shut down of at any point may idles the entire system.
6. Servicing requires more skill.

Application of Automation
1. Automatic machine tools to process parts
2. Automatic assembly machine
3. Industrial robots
4. Automatic material handling and storage systems
5. Automatic inspection system for quality control
6. Feed back control and computer process control
7. Computer systems for planning data collection, and decision making to support manufacturing
activities.
8. Automated systems used in discrete product manufacturing industries include metal working,
electronics, automotive, appliances, aircraft, and many others.

Types of Automation
We can classify automation into four categories.

1. Fixed automation
2. Programmable automation
3. Flexible automation
4.Integrated automation

1. Fixed Automation
It is practiced for high volume mass production. Here
dedicated equipments, optimized to perform a
sequence of operations is used to achieve low cost
and high productivity. The equipments are not
flexible to take a change in product design. The typical features of fixed automation are

 High initial investment of custom-engineered equipment

 High production rates
 Relatively inflexible to accommodate product changes

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Examples of fixed automation are transfer lines and automatic assembly lines. Welding, painting, pick and
face robots, and conveyer systems are examples of fixed automation equipments.

2. Programmable Automation
Programmable automation equipment has the capability to change the sequence of operations to adopt to
different product configurations. The Operation sequence is controlled by a program which is a set of
instructions coded so that the system can read and interpret them. By changing the program, the equipment
can be programmed to perform a variety of tasks. Some of the features that characterize programmable
automation include.

* High investment in general-purpose equipment

* Low production rates compared to fixed automation

* Flexibility to deal with changes in product configuration

* Most suitable for batch production.

Examples of programmable automation equipment include NC machines, assembly robots and automated
guided vehicles (ABV's).

3. Flexible Automation
It is an extension of programmable automation. The system have the capability to maintain competitive
production of a variety of part types in low to mid volume ranges, in the face of design, demand and part mix
changes and machine and tool failures. There is no production time lost while reprogramming the system and
altering the physical setup (tooling, fixtures, machine settings). The features of flexible automation can be
summarized as follows.

* High investment for a custom-engineered system

* Continuous production of variable mixtures of products
* Medium production rate
* Flexible to deal with product design variations
Examples of flexible automation are provided by flexible manufacturing systems for performing machining
operations
4. Integrated Automation
It involves logical organization of design, engineering testing, production, marketing and distribution
functions into a computer integrated system. This concept thus facilitates integration of all phases of
manufacturing from product conception and planning through shipping and delivery, and involves the highest
level of integration among the various manufacturing functions of the firm.

Basic Elements of Automated System

There are four basic elements in an automated system.

1. Actuator

The first element includes the actuator which does the work. These are the work horses of the system. They
provide the movement to drive the system. It gets energy from different sources like electricity, pneumatics or
hydraulics. Some actuators can only be on and off. Other actuators respond proportionally with the signal
they receive from a controller.

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 2. Sensor

The second element includes the sensors that monitor the environment for action. They measure certain
quantities like temperature, stress, light, or proximity. This can give indications of the running conditions of
the system, a step in a process, an error condition, or be used to validate a safe operating condition. Switches
and transducers are also used as sensors.

3. Controller

The third element involves the controller. It controls the motion and operation of the system components
based on inputs from sensors and the internal programmed instructions. A controller would be thought of as
“the brain” of the system. It makes decisions and performs the corresponding action.

4. Mechanical system

The final element is the mechanical system, or mechanism. This category consists of the other hardware
included in the autonomous system. These mechanisms or components are used with actuators and drives to
perform specific tasks.

Definition of Mechatronics
Mechatronics is the integration of microprocessor control systems, electrical systems and mechanical systems

Advantages of Mechatronic System

a) Enhanced features and functionality.
b) More user friendly
c) Precision control
d) Simplified mechanical design
e) Rapid machine setup
f) The products produced are cost effective and very good quality.
g) Rapid development trials
h) Possibilities for adaptation during commissioning
i) High performance, productivity and reliability due to sensors and feed back system
j) High degree of flexibility
k) Greater extent of machine utilization
l) High life expected by proper maintenance.

Disadvantages of Mechatronics system

a. Expertise in different engineering fields are required
b. More complex safety issues
c. Increase in component failures
d. Increased power requirements
e. Higher initial cost of the system.
f. Specific problem of various systems will have to be addressed separately and properly
g. It is expensive to incorporate Mechatronics approaches to existing/old systems.

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Classification of Mechatronics Products
In the late 19703, the Japan Society for the promotion of Machine Industry classified mechatronics products
into four categories as follows

1. Class I : Primary mechanical products with electronics incorporated to enhance functionality. Examples
include numerically controlled machine tools and variable speed drives in manufacturing machines.

2. Class II : Traditional mechanical systems with significantly updated internal devices incorporating
electronics. The external user interfaces are unaltered. Examples are modern sewing machines and automated
manufacturing system.

3. Class III : Systems that retain the functionality of the traditional mechanical system. but the internal
mechanisms are replaced by electronics. An example is the digital watch

4. Class IV : Products designed with mechanical and electronic technologies through synergic integration .
Examples include photocopiers, intelligent washers and dryers, rice cookers, and automatic ovens.

Block Diagram of Mechatronics System

Major building blocks of any mechatronic system are:

1. Measurement and actuation module

2. Communication module
3. CPU
4. Output signal conditioning module.
5. Feedback module.
1. Measurement and actuation module
It receives signals from external environment and feedback signal. This module uses several actuators and
sensors such as solenoids, AC/DC and stepper motor, switches, strain gauge, temperature/pressure/photo
sensors. These sensors can be adjusted manually.

2. Communication module

The position of sensors and the relative position of actuators are measured and corresponding signals are
generated. These signals are feed to CPU through a communication module. The communication module
includes signal conditioning circuits, interfacing circuits and bus communication.

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3. CPU

CPU with a processor and necessary software performs the logical and arithmetic operations on the signal
received, CPU then generates suitable control signa1.

4.Output signal conditioning module

It consists of output conditioning module consists of analog to digital converter(ADC) / DACs, amplifiers,
audiovisual indicators and displays.

Measurement Systems
A fundamental part of many mechatronic systems is a measurement system composed of the three basic parts.
The transducer/ sensor is a sensing device that converts a physical Input into an output signal, usually a
voltage. The signal processor performs filtering, amplification or other signal conditioning on the transducer
output. The term sensor is often used to refer to the transducer or to the combination of transducer and signal
processor. A display that maintains the sensor data for online monitoring or subsequent processing.

Control systems
A control system regulates the output from a device so as to maintain it constant at a predetermined level.

Example: water level controller. Control system switches the pump on / off to keep the level of water constant
within some limits.

Control system is classified into two

1. Open loop control systems

2. Closed loop control systems

Open loop control systems

In open loop control systems only the input is controlled without any reference to the output. Thus
the output is independent of the control action at the input.
Example: room heating system without sensing feedback, Traffic light system.

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  These systems are simple in construction.
 They are inaccurate and unreliable.
 Less maintenance because of absence of sophisticated measuring and comparison systems.
 Less cost

Closed loop control system

In a closed loop control system the control action at the input is governed by the output conditions. For this
output measuring devices and comparing system are included in the closed loop system. The measurement
system senses the variation in the output and sends the feedback signals to the comparison system which
suitably controls the input.

 These systems are accurate, stable and less affected by noise.

 But these systems are sophisticated and hence costly.
 Response time between the output and the input is very less, hence works economically.
 Needs no manual operation.

To convert a water level controller into a closed loop system, an electric water level control system is
connected at the input side to serve as comparison system, and the water level sensors immersed in the
discharge tank serve as measuring system. There will be two water level sensors, one for the minimum level
and the other for the maximum level. Whenever the water levels reaches maximum or the minimum point the
corresponding sensor sends the feedback signal to the electronic water level controller and it operates the
pump accordingly..

Elements of Design Procedure

The design process for any system can be considered as involving a number of stages as follows

l. The need

The design process begins with a need from, perhaps, a customer or client. This may ht identified by market
research being used to establish the needs of potential customers.

2. Analysis of the problem

The first stage in developing a design is to find out the true nature of the problem i.e. analysing it. This is an
important stage in that not defining the problem accurately can lead to waste of time on designs that will not
fulfill the need.

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3. Preparation of specification.

Following the analysis, a specification of the requirement can be prepared. This will state the problem, any
constraints placed on the solution, and the criteria which may be used to judge the quality of the design. In
stating the problem, all the functions required of the design, together, with any desirable features, should be
specified. Thus there might be a statement of mass, dimensions, types and range of motion required,
accuracy, input and output requirements of elements, interfaces, power requirements, operating environment,
relevant standards and codes of practice, etc.

4. Generation of possible solutions.

This is often termed as the conceptual stage. Outline solutions are prepared which are worked out in sufficient
detail to indicate the means of obtaining each of the required functions like approximate sizes, shapes,
materials and costs. It also means finding out what has been done before for similar problems; there is no
sense in reinventing the wheel.

5. Selection of a suitable solution.

The various solutions are evaluated and the most suitable one selected.

6. Production of a detailed design

The detail of the selected design has now to be worked out. This might require the production prototypes or
mock-ups in order to determine the optimum details of a design.

7. Production of working drawing.

The selected design is then translated into working drawings, circuit diagrams, etc. so that the item can be
made.