Electric Drives and Electromechanical Systems

Applications and Control

Richard Crowder

• Publisher: Butterworth-Heinemann
• Year: 2019
• ISBN:
  9780081028858
• Edition: 2
• Topic: Tecnologia e ingegneria
• Subtopic: Ingegneria elettronica e telecomunicazioni

Electric Drives and Electromechanical Devices: Applications and Control, Second Edition, presents a unified approach to the design and application of modern drive system. It explores problems involved in assembling complete, modern electric drive systems involving mechanical, electrical, and electronic elements. This book provides a global overview of design, specification applications, important design information, and methodologies.This new edition has been restructured to present a seamless, logical discussion on a wide range of topical problems relating to the design and specification of the complete motor-drive system. It is organised to establish immediate solutions to specific application problem. Subsidiary issues that have a considerable impact on the overall performance and reliability, including environmental protection and costs, energy efficiency, and cyber security, are also considered.

• Presents a comprehensive consideration of electromechanical systems with insights into the complete drive system, including required sensors and mechanical components
• Features in-depth discussion of control schemes, particularly focusing on practical operation
• Includes extensive references to modern application domains and real-world case studies, such as electric vehicles
• Considers the cyber aspects of drives, including networking and security

1

Electromechanical systems

Abstract

In the design of any complex system, all the relevant design details must be considered to ensure the development of a successful product. When designing any actuation system, cross discipline working is required, and if care is not taken, confusion will result. The initial step in the selection of any element of a motor-drive system is to determine a clear understanding of its requirements both mechanically (e.g. torque, force speed, fixings) and electrical (e.g. power supply, sensing requirements, network interface). In this chapter, a range of applications is considered, ranging from industrial automation through to the aerospace and automotive sectors., and the key features highlighted.

Keywords

Actuators; Manufacturing systems; Robotics; Automotive applications; Aerospace applications

1. 1.1 Principles of automation
2. 1.2 Machine tools
   1. 1.2.1 Conventional subtractive machining processes
   2. 1.2.2 Non-conventional subtractive machining processes
   3. 1.2.3 Additive manufacturing processes
   4. 1.2.4 Machining centres
3. 1.3 Robotics
   1. 1.3.1 Industrial robotics
   2. 1.3.2 Robotic end effectors
   3. 1.3.3 Mobile and swarm robotics
   4. 1.3.4 Walking robots
4. 1.4 Automotive applications
   1. 1.4.1 Conventional vehicles
   2. 1.4.2 Electric vehicles
5. 1.5 Aerospace applications
6. 1.6 Motion-control systems
7. 1.7 Summary
8. References

In the design of any complex system, all the relevant design details must be considered to ensure the development of a successful product. In the development of motion systems, problems in the design process are most likely to occur in the actuator or motor-drive system. When designing any actuation system, mechanical designers work with electrical and electronic systems engineers, and if care is not taken, confusion will result. The objective of this book is to discuss some of the electric motor-drive systems in common use, and to identify the issues that arise in the selection of the correct components and systems for specific applications.

The initial step in the selection of any element of a motor-drive system is to determine a clear understanding of its requirements both mechanically (e.g. torque, force speed, fixings) and electrical (e.g. power supply, sensing requirements, network interface). In this chapter, a range of applications is considered, ranging from industrial automation through to the aerospace and automotive sectors.

1.1. Principles of automation

Automation is defined as the technology which is concerned with the application of mechanical, electrical, and computer systems in the operation and control of a processes. In general, an automated production process can be classified into one of three groups: fixed, programmable, or flexible.

1. • Fixed automation is typically employed for products with a very high production rate; the high initial cost of fixed-automation plant can therefore be spread over a very large number of units. Fixed-automation systems are used to manufacture products as diverse as cigarettes and steel nails. The significant feature of fixed automation is that the sequence of the manufacturing operations is fixed by the design of the production machinery, and therefore the sequence cannot easily be modified at a later stage of a product's life cycle.
2. • Programmable automation can be considered to exist where the production equipment is designed to allow a range of similar products to be produced. The production sequence is controlled by a stored program, but to achieve a product change-over, considerable reprogramming and tooling changes will be required. In any case, the process machine is a stand-alone item, operating independently of any other machine in the factory; this principle of automation can be found in most manufacturing processes and it leads to islands of automation. The concept of programmable automation has its roots in the Jacquard looms of the nineteenth century, where weaving patterns were stored on a punched-card system.
3. • Flexible automation is an enhancement of programmable automation in which a computer-based manufacturing system has the capability to change the manufacturing program and the physical configuration of the machine tool or cell with a minimal loss in production time. In many systems the machining programs are prepared at a location remote from the machine, and they are then transmitted as required over a computer-based local-area communication network.

The basic design of machine tools and other systems used in manufacturing processes changed little from the eighteenth century to the late 1940s. There was a gradual improvement during this period as the metal cutting changed from an art to a science as there was an increased understanding of the materials used in cutting tools. However, the first significant change to machine-tool technology was the introduction of numerical-control (NC) and computer-numerical-control (CNC) systems.

To an operator, the differences between these two technologies are small, both operate from a stored program, which was originally on punched tape, then computer media such as magnetic tapes and discs, and currently stored centrally and distributed over a network. The stored program in a NC machine is directly read and used to control the machine; the logic within the controller is dedicated to that task. A CNC machine tool incorporates a dedicated computer to execute the program. The use of the computer gives a considerable number of other features, including data collection and communication with other machine tools or computers over a computer network. In addition to the possibility of changing the operating program of a CNC system, the executive software of the computer can be changed, which allows the performance of the system to be modified at minimum cost. The application of NC and CNC technology permitted a complete revolution of the machine tool industry and the manufacturing industries it supported. The introduction of electronic systems into conventional machine tools was initially undertaken in the late 1940s by the United States Air Force to increase the quality and productivity of machined aircraft parts. The rapid advances of electronics and computing systems during the 1960s and 1970s permitted the complete automation of machine tools and the parallel development of industrial robots. This was followed during the 1980s by the integration of robots, machine tools, and material handling systems into computer-controlled factory environments. The logical conclusion of this trend is that individual product quality is no longer controlled by direct intervention of an operator. Since the machining parameters are stored either within the machine or at a remote location for direct downloading via a network (see Chapter 11) a capability exists for the complete repeatability of a product, both by mass production and in limited batches (which can be as small as single components). Until the 1990's machining normally involved the removal of material from the workpiece to form the final object – this is subtractive machine...