Modern high-tech engineering requires the multidisciplinary study of integrated systems. This requires a broad knowledge and understanding of physical systems such as mechanical, electrical, electronic, hydraulic, and pneumatic systems. To this end, we introduce a unified modeling method using a bond graph technique. Understanding magnetic systems can also help us understand the principles of electromechanical systems such as electric motors or electric generators, and how to control them, such as robots and drones. This technique can give mechanical and electronic engineering students the ability to easily understand and design electronic and mechanical systems, respectively, even if they are not their majors. It can also help fluid engineering researchers understand their concepts without having to memorize complex fluid-related formulas.

While physical systems can be solved directly in the time domain to understand their behavior, it is sometimes more convenient to understand and interpret the system from the relationship between an inputs and output in the frequency domain. This is because mechanical engineers do not need to use mathematical methods to find the exact behavior of a physical system, but it is more important to obtain a solution that is consistent with physical concepts, even if it is approximate.

Mechanical systems can be unstable or have a small damping ratio, which causes large oscillations. In addition, uncertainties exist in the high-frequency region, which makes system modeling difficult. This book introduces traditional control theory, focusing on frequency analysis, to explain why these types of problems are difficult to solve with conventional PID controllers and how to solve them. In addition, it is introduced the functions of a voltage or current amplifiers and a sensor required for actual control and how their specifications should be selected not to affect the control performances.

보편적이고 통일된 모델링 방법 소개!

현대의 하이테크 엔지니어링은 통합 시스템에 대한 다학제적 연구를 필요로 한다. 이를 위해서는 기계, 전기, 전자, 유압 및 공압 및 자기 시스템 등의 물리 시스템에 대한 폭넓은 지식과 이해가 필수적이다. 이를 위해 본드 그래프 기법을 이용하여 보편적이고 통일된 모델링 방법을 소개한다. 이와 같은 기법은 기계공학도와 전자공학도가 각각 전자 시스템과 기계 시스템을 쉽게 이해하고 설계할 수 있는 능력 및 유체 공학 연구자가 복잡한 유체 관련 수식을 굳이 기억하지 않고도 이들의 개념을 이해하는 데 많은 도움을 줄 수 있다. 또한 자기 시스템의 이해는 전기 모터 또는 전기 발전기와 같은 전자-기계 시스템의 원리를 이해하고 로봇이나 드론 등의 제어 방법을 이해하는 것이 필수적이다.

물리적 시스템은 시간 영역에서의 해를 직접적으로 구해 거동을 이해할 수 있지만 주파수 영역에서 입력과 출력 사이의 관계식으로부터 시스템을 이해하고 해석하는 것이 더 편리할 때가 있다. 기계 공학도는 수학적인 방법을 이용하여 물리적 시스템의 정확한 거동이나 해를 구하는 것이 아니고 물리적인 개념에 일치한 해를 얻는 것이 더 중요하기 때문이다.

때때로 기계 시스템은 불안정하거나 감쇠비가 작아 큰 진동을 유발하는 일부 구성 요소가 큰 진동을 유발한다. 또한 고주파 영역에 불확실성이 존재하기 때문에 시스템 모델링을 어렵게 만든다. 이러한 유형의 문제가 왜 기존의 PID제어기로 해결하기 어려우며 어떻게 해결해야 하는지를 주파수 분석에 중점을 두어 전통적인 제어 이론을 소개하고자 한다. 또한 실제 제어에 필요한 전압 또는 전류 증폭기와 센서들의 기능과 사양이 왜 중요하며 어떻게 선정되어야 하는지에 대한 내용도 소개하고 있다. 

Dr. Kyihwan Park

Dr. Kyihwan Park, was born in January 1961 in Mokpo, Jeollanam-do, South Korea. He received the B.S. and M.S. degrees from the Department of Mechanical Design and Production Engineering, Seoul National University in 1985 and 1987, respectively, and the Ph.D. degree from the University of Texas at Austin, USA, in August 1993. He joined the Department of Mechatronics Engineering, Gwangju Institute of Science and Technology (GIST) in September 1995 and has been a professor in the Department of Mechanical Engineering since then. Since September 2004, he has served as the Chairman of the Department of Mechanical Engineering for two years, and since June 2012, he has served as the Director of the Industry-Academia Cooperation center (GTI) for four years, and is currently the Director of Advanced Military Science and Technology (CAMST) Center since July 2019. His research interests include optical sensors and actuators, electromagnetic-based dynamical system design and control, signal processing, and vibration control of precision systems. His current research focuses on the development and application of various LIDAR (light detection and ranging) technologies. In particular, he is commercializing and selling non-contact laser vibrometers for vibration measurement and atomic force microscopes through EM4SYS, which he founded in June 2000.

CHAPTER 01 Conventional modeling methods

1.1 Modeling process

1.2 Input sources in mechanical systems

1.3 Constitutive relations

1.4 Modeling of mechanical systems

1.5 Load effect

1.6 Passive system; non-isolated system

CHAPTER 02 Bond graph modeling for mechanical system

2.1 Power flow in physical systems

2.2 Bond graph modeling in mechanical systems

2.3 Causality

2.4 State equations

CHAPTER 03 Bond graph modeling for electrical systems

3.1 Constitutive relations

3.2 Bond graph model of electric circuits

3.3 Voltage source and current source in electric circuits

3.4 State equations of electrical circuits

3.5 Causality problem in an electronic circuit

3.6 Bond graph for hydraulic systems

3.7 Pneumatic systems

CHAPTER 04 Response analysis

4.1 Time response analysis for a first order system

4.2 Time response analysis using the Laplace transformation method

4.3 Time response analysis of a second-order system

4.4 Frequency response analysis

4.5 Steady state response analysis for various time inputs

4.6 Transient response based on frequency response analysis

4.7 Frequency response of a high-order system

CHAPTER 05 Electromechanical systems

5.1 Magnetic field system

5.2 Analysis of the magnetic field system

5.3 Magnetic circuit theory

5.4 Magnetic field analysis of a permanent magnet

5.5 Magnetic field in a moving media

5.6 Bond graph representation of an electromechanical system

5.7 Various electromechanical systems

5.8 Appendix

CHAPTER 06 Control

6.1 Why is a feedback loop needed?

6.2 Feed-forward transfer function

6.3 Analysis of the closed loop system

6.4 Analysis of an open loop system

6.5 Compensator design

6.6 Design of control components for good command following

6.7 Stability of an electronic system

6.8 Sampling effect on control

6.9 Control applications

6.10 Loop shaping controller

CHAPTER 07 Controller implementation using operational amplifiers

7.1 Load-effect-free operational ampliflier

7.2 Amplifiers

7.3 Various controller using operational amplifiers

7.4 Electronic circuits for a plant realization and feedback control

7.5 Experiment of feedback control

CHAPTER 08 Signal processing for sensing systems

8.1 Sensor specifications

8.2 Components of optical sensors

8.3 Amplitude modulation

8.4 Phase and frequency modulation