E1C12 09/14/2010
13:54:8 Page 504
Chapter 12
Mechatronics
1
: Sensors, Actuators,
and Controls
12.1 INTRODUCTION
Rapid advances in microprocessors have led to a dramatic increase in electronically controlled
devices and systems. All of these systems require sensors and actuators to be interfaced with the
electronics. Understanding the operating principles and limitations of sensors is essential to
selecting and interfacing sensors for linear motion, rotary motion, and engineering variables
such as force torque and power. Actuators are required to produce motion, such as to move an
electric car seat, for a fly-by-wire throttle for automotive applications, or for positioning a precision
laser welder. This chapter discusses sensors and actuators, and provides a brief introduction to linear
control theory.
Upon completion of this chapter, the reader will be able to
describe and analyze methods for displacement measurement,
state the physical principles underlying velocity and acceleration measurements,
describe various load cells and their appropriate applications,
describe various methods for measuring torque and power,
describe various actuators and their role in mechatronic systems, and
analyze proportional-integral-derivative (PID) control schemes as part of a mechatronic
system.
12.2 SENSORS
The previous chapters described a wide variety of measurement sensors and the fundamentals of
their operation. Thermocouples, strain gauges, flow meters, and pressure sensors represent the
means to measure the very important engineering process variables of temperature, strain, flow rate,
and pressure. In this chapter we add to this base by introducing methods and sensors for the
measurement of linear and rotary displacement, acceleration and vibration, velocity measurement,
force or load, torque, and mechanical power.
1 The term ‘‘mechatronics’’ is derived from the terms ‘‘mechanical’’ and ‘‘electronic,’’ and refers to the integration of
mechanical and electronic devices.
504
13:54:8 Page 504
Chapter 12
Mechatronics
1
: Sensors, Actuators,
and Controls
12.1 INTRODUCTION
Rapid advances in microprocessors have led to a dramatic increase in electronically controlled
devices and systems. All of these systems require sensors and actuators to be interfaced with the
electronics. Understanding the operating principles and limitations of sensors is essential to
selecting and interfacing sensors for linear motion, rotary motion, and engineering variables
such as force torque and power. Actuators are required to produce motion, such as to move an
electric car seat, for a fly-by-wire throttle for automotive applications, or for positioning a precision
laser welder. This chapter discusses sensors and actuators, and provides a brief introduction to linear
control theory.
Upon completion of this chapter, the reader will be able to
describe and analyze methods for displacement measurement,
state the physical principles underlying velocity and acceleration measurements,
describe various load cells and their appropriate applications,
describe various methods for measuring torque and power,
describe various actuators and their role in mechatronic systems, and
analyze proportional-integral-derivative (PID) control schemes as part of a mechatronic
system.
12.2 SENSORS
The previous chapters described a wide variety of measurement sensors and the fundamentals of
their operation. Thermocouples, strain gauges, flow meters, and pressure sensors represent the
means to measure the very important engineering process variables of temperature, strain, flow rate,
and pressure. In this chapter we add to this base by introducing methods and sensors for the
measurement of linear and rotary displacement, acceleration and vibration, velocity measurement,
force or load, torque, and mechanical power.
1 The term ‘‘mechatronics’’ is derived from the terms ‘‘mechanical’’ and ‘‘electronic,’’ and refers to the integration of
mechanical and electronic devices.
504