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AUTOMATION & ROBOTICS

JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY ANANTAPUR B.Tech. IV-I Sem (M.E)

(9A03702) AUTOMATION & ROBOTICS UNIT – I Introduction to Automation: Need , Types, Basic elements of an automated system, levels of automation, hardware components for automation and process control, mechanical feeders, hoppers, orienters, high speed automatic insertion devices. UNIT – II Automated flow lines: Part transfer methods and mechanisms, types of Flow lines, flow line with/without buffer storage, qualitative analysis. UNIT – III Assembly line balancing: Assembly process and systems assembly line, line balancing methods, ways of improving line balance, flexible assembly lines. UNIT – IV Introduction to Industrial Robots: Classification. Robot configurations, Functional line diagram, Degrees of Freedom. Components, common types of arms, joints, grippers. UNIT – V Manipulator Kinematics: Homogeneous transformations as applicable to rotation and translation - D-H notation, Forward and inverse kinematics. Manipulator Dynamics: Differential transformation, Jacobians . Lagrange – Euler and Newton – Euler formations. UNIT VI Trajectory Planning: Trajectory planning and avoidance of obstacles, path planning, Skew motion, joint integrated motion – straight line motion . Robot programming-Types – features of languages and software packages. UNIT VII Robot actuators and Feed back components: Actuators: Pneumatic, Hydraulic actuators, electric & stepper motors, comparison. Position sensors – potentiometers, resolvers, encoders – Velocity sensors, Tactile sensors, Proximity sensors. UNIT VIII Robot Application in Manufacturing: Material Transfer - Material handling, loading and unloadingProcessing - spot and continuous arc welding & spray painting - Assembly and Inspection. TEXT BOOKS: 1. Automation , Production systems and CIM,M.P. Groover/Pearson Edu. 2. Industrial Robotics - M.P. Groover, TMH. REFERENCES: 1. Robotics , Fu K S, McGraw Hill. 2. An Introduction to Robot Technology , P. Coiffet and M. Chaironze , Kogam Page Ltd. 1983 London. 3. Robotic Engineering , Richard D. Klafter, Prentice Hall 4. Robotics, Fundamental Concepts and analysis – Ashitave Ghosal,Oxford Press 5. Robotics and Control , Mittal R K & Nagrath I J , TMH. 6. Introduction to Robotics – John J. Craig,Pearson Edu

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Prepared by D.K. JAWAD, Assoc. Prof. Gates Institute of Technology

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AUTOMATION & ROBOTICS

UNIT – I: INTRODUCTION TO AUTOMATION Automation or automatic control, is the use of various control systems for operating equipment such as machinery, processes in factories, boilers and heat treating ovens, switching in telephone networks, steering and stabilization of ships, aircraft and other applications with minimal or reduced human intervention. Some processes have been completely automated. The biggest benefit of automation is that it saves labor, however, it is also used to save energy and materials and to improve quality, accuracy and precision. The term automation, inspired by the earlier word automatic (coming from automaton), was not widely used before 1947, when General Motors established the automation department. It was during this time that industry was rapidly adopting feedback controllers, which were introduced in the 1930s. Automation has been achieved by various means including mechanical, hydraulic, pneumatic, electrical, and electronic and computers, usually in combination. Complicated systems, such as modern factories, airplanes and ships typically use all these combined techniques. The main advantages of automation are: •Increased throughput or productivity. •Improved quality or increased predictability of quality. •Improved robustness (consistency), of processes or product. •Increased consistency of output. •Reduced direct human labor costs and expenses. The following methods are often employed to improve productivity, quality, or robustness. •Install automation in operations to reduce cycle time. •Install automation where a high degree of accuracy is required. •Replacing human operators in tasks that involve hard physical or monotonous work.[16] •Replacing humans in tasks done in dangerous environments (i.e. fire, space, volcanoes, nuclear facilities, underwater, etc.) •Performing tasks that are beyond human capabilities of size, weight, speed, endurance, etc. •Economic improvement: Automation may improve in economy of enterprises, society or most of humanity. For example, when an enterprise invests in automation, technology recovers its investment; or when a state or country increases its income due to automation like Germany or Japan in the 20th Century. •Reduces operation time and work handling time significantly. •Frees up workers to take on other roles. •Provides higher level jobs in the development, deployment, maintenance and running of the automated processes. The main disadvantages of automation are: •Causing unemployment and poverty by replacing human labor. •Security Threats/Vulnerability: An automated system may have a limited level of intelligence, and is therefore more susceptible to committing errors outside of its immediate scope of knowledge (e.g., it is typically unable to apply the rules of simple logic to general propositions). •Unpredictable/excessive development costs: The research and development cost of automating a process may exceed the cost saved by the automation itself. •High initial cost: The automation of a new product or plant typically requires a very large initial investment in comparison with the unit cost of the product, although the cost of automation may be spread among many products and over time. In manufacturing, the purpose of automation has shifted to issues broader than productivity, cost, and time.

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Prepared by D.K. JAWAD, Assoc. Prof. Gates Institute of Technology

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Robotics is the branch of mechanical engineering, electrical engineering and computer science that deals with the design, construction, operation, and application of robots,[1] as well as computer systems for their control, sensory feedback, and information processing. These technologies deal with automated machines that can take the place of humans in dangerous environments or manufacturing processes, or resemble humans in appearance, behavior, and/or cognition. Many of today's robots are inspired by nature contributing to the field of bio-inspired robotics. The concept of creating machines that can operate autonomously dates back to classical times, but research into the functionality and potential uses of robots did not grow substantially until the 20th century. Throughout history, robotics has been often seen to mimic human behavior, and often manage tasks in a similar fashion. Today, robotics is a rapidly growing field, as technological advances continue, research, design, and building new robots serve various practical purposes, whether domestically, commercially, or militarily. Many robots do jobs that are hazardous to people such as defusing bombs, mines and exploring shipwrecks.

1.1 NEED: Companies undertake projects in manufacturing automation and computer-integrated manufacturing for a variety of good reasons. Some of the reasons used to justify automation are the following: 1. To increase labor productivity: Automating a manufacturing operation usually increases production rate and labor productivity. This means greater output per hour of labor input. 2. To reduce labor cost: Ever-increasing labor cost has been and continues to be the trend in the world‘s industrialized societies. Consequently, higher investment in automation has become economically justifiable to replace manual operations. Machines are increasingly being substituted for human labor to reduce unit product cost. 3. To mitigate the effects of labor shortages: There is a general shortage of labor in many advanced nations, and this has stimulated the development of automated operations as a substitute for labor. 4. To reduce or eliminate routine manual and clerical tasks: An argument can be put forth that there is social value in automating operations that are routine, boring, fatiguing, and possibly irksome. Automating such tasks serves a purpose of improving the general level of working conditions. 5. To improve worker safety: By automating a given operation and transferring the worker from active participation in the process to a supervisory role, the work is made safer. The safety and physical well being of the worker has become a national objective with the enactment of the Occupational Safety and Health Act (OSHA) in 1970. This has provided an impetus for automation. 6. To improve product quality: Automation not only results in higher production rates than manual operations; it also performs the manufacturing process with greater uniformity and conformity to quality specifications. Reduction of fraction defect rate is one of the chief benefits of automation. 7. To reduce manufacturing lead time: Automation helps to reduce the elapsed time between customer order and product delivery, providing a competitive advantage to the manufacturer for future orders. By reducing manufacturing lead time, the manufacturer also reduces work-in-process inventory. 8. To accomplish processes that cannot be done manually: Certain operations cannot be accomplished without the aid of a machine. These processes have requirements for precision, miniaturization, or complexity of geometry that cannot be achieved manually. Examples include certain integrated circuit fabrication operations, rapid prototyping processes based on computer graphics (CAD) models, and the machining of complex, mathematically defined surfaces using computer numerical control. These processes can only be realized by computer controlled systems. 9. To avoid the high cost of not automating: There is a significant competitive advantage gained in automating a manufacturing plant. The advantage cannot easily be demonstrated on a company‘s project authorization form. The benefits of automation often show up in unexpected and intangible ways, such as in improved quality, higher sales, better labor relations, and better company image. Companies that do not automate are likely to find themselves at a competitive disadvantage with their customers, their employees, and the general public. 3 | Page

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1.2 TYPES OF AUTOMATION IN THE INDUSTRY: Automated manufacturing systems can be classified into three basic types (for our purposes in this introduction; we explore the topic of automation in greater depth in Chapter 3): (1) fixed automation, (2) programmable automation, and (3) flexible automation. Fixed Automation: Fixed automation is a system in which the sequence of processing (or assembly) operations is fixed by the equipment configuration. Each of the operations in the sequence is usually simple, involving perhaps a plain linear or rotational motion or an uncomplicated combination of the two; for example, the feeding of a rotating spindle. It is the integration and coordination of many such operations into one piece of equipment that makes the system complex.Typical features of fixed automation are: • high initial investment for custom-engineered equipment • high production rates • relatively inflexible in accommodating product variety The economic justification for fixed automation is found in products that are produced in very large quantities and at high production rates. The high initial cost of the equipment can be spread over a very large number of units, thus making the unit cost attractive compared with alternative methods of production. Examples of fixed automation include machining transfer lines and automated assembly machines. Programmable Automation: In programmable automation, the production equipment is designed with the capability to change the sequence of operations to accommodate different product configurations.The operation sequence is controlled by a program, which is a set of instructions coded so that they can be read and interpreted by the system. New programs can be prepared and entered into the equipment to produce new products. Some of the features that characterize programmable automation include: • high investment in general purpose equipment • lower production rates than fixed automation • flexibility to deal with variations and changes in product configuration • most suitable for batch production Programmable automated production systems are used in low- and medium-volume production. The parts or products are typically made in batches. To produce each new batch of a different product, the system must be reprogrammed with the set of machine instructions that correspond to the new product. The physical setup of the machine must also be changed: Tools must be loaded, fixtures must be attached to the machine table, and the required machine settings must be entered. This changeover procedure takes time. Consequently, the typical cycle for a given product includes a period during which the setup and reprogramming takes place, followed by a period in which the batch is produced. Examples of programmable automation include numerically controlled (NC) machine tools, industrial robots, and programmable logic controllers. Flexible Automation: Flexible automation is an extension of programmable automation. A flexible automated system is capable of producing a variety of parts (or products) with virtually no time lost for changeovers from one part style to the next. There is no lost production time while reprogramming the system and altering the physical setup (tooling, fixtures, machine settings). Consequently, the system can produce various combinations and schedules of parts or products instead of requiring that they be made in batches. What makes flexible automation possible is that the differences between parts processed by the system are not significant. It is a case of soft variety, so that the amount of changeover required between styles is minimal. 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 rates • flexibility to deal with product design variations Examples of flexible automation are the flexible manufacturing systems for performing machining operations that date back to the late 1960s. The relative positions of the three types of automation for 4 | Page

Prepared by D.K. JAWAD, Assoc. Prof. Gates Institute of Technology

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AUTOMATION & ROBOTICS

different production volumes and product varieties are depicted in Figure 1.1. For low production quantities and new product introductions, manual production is competitive with programmable automation.

1.3 BASIC ELEMENTS OF AN AUTOMATED SYSTEM: An automated system consists of three basic elements: (1) power to accomplish the process and operate the system. (2) a program of instructions to direct the process, and (3) a control system to actuate the instructions. The relationship amongst these elements is illustrated in Figure 1.2. All systems that qualify as being automated include these three basic elements in one form or another.

Power to Accomplish the Automated Process: An automated system is used to operate some process, and power is required to drive the process as well as the controls. The principal source of power in automated systems is electricity. Electric power has many advantages in automated as well as nonautomated processes. •Electrical power is widely available at moderate cost. It is an important part of our industrial infrastructure • Electrical power can be readily converted 10 alternative energy forms: mechanical, thermal, light, acoustic, hydraulic, and pneumatic. • Electrical power at low levels can be used to accomplish functions such as signal transmission, information processing, and data storage and communication. • Electrical energy can be stored in long-life batteries for use in locations where an external source of electrical power is not conveniently available. Alternative power sources include fossil fuels, solar energy, water, and wind. However, their exclusive use is rare in automated systems. In many cases when alternative power sources are used to drive the process itself, electrical power is used for the controls that automate the operation. For example, in casting or heat 5 | Page

Prepared by D.K. JAWAD, Assoc. Prof. Gates Institute of Technology

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treatment, the furnace may be heated by fossil fuels, but the control system to regulate temperature and time cycle is electrical. In other cases, the energy from these alternative sources is converted to electric power to operate both the process and its automation. When solar energy is used as a power source for an automated system, it is generally converted in this way. Power for the Process: In production, the term process refers to the manufacturing operation that is performed on a work unit. In Table 1.1, a list of common manufacturing processes is compiled along with the form of power required and the resulting action on the work unit. Most of the power in manufacturing plants is consumed by these kinds of operations. The "power form" indicated in the middle column of the table refers to the energy that is applied directly to the process. As indicated above, the power source for each operation is usually converted from electricity.

In addition to driving the manufacturing process itself, power is also required for the following material handling functions: • Loading and unloading the work unit: All of the processes listed in Table 1.1 are accomplished on discrete parts. These parts must be moved into the proper position and orientation for the process to be performed, and power is required for this transport and placement function. At the conclusion of the process, the work unit must similarly be removed. If the process is completely automated, then some form of mechanized power is used. If the process is manually operated or semi-automated, then human power may be used to position and locate the work unit • Material transport between operations: In addition 10 loading and unloading at a given operation, the work units must be moved between operations. We consider the material handling technologies associated with this transport function. Power for Automation: Above and beyond the basic power requirements for the manufacturing operation, additional power is required for automation. The additional power is used for the following functions: • Controller unit: Modern industrial controllers are based on digital computers, which require electrical power to read the program of instructions, make the control calculations, and execute the instructions by transmitting the proper commands to the actuating devices. 6 | Page

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AUTOMATION & ROBOTICS

• Power to actuate the control signals: The commands sent by the controller unit are carried out by means of electromechanical devices, such as switches and motors, called actuators. The commands are generally transmitted by means of low-voltage control signals. To accomplish the commands, the actuators require more power, and so the control signals must he amplified to provide the proper power level for the actuating device. • Data acquisition and information processing: In most control systems, data must be collected from the process and used as input to the control algorithms. In addition, a requirement of the process may include keeping records of process performance or product quality. These data acquisition and record keeping functions require power, although in modest amounts. Control System: The control element of the automated system executes the program of instructions. The control system causes the process to accomplish its defined functi...