Sensors for Mechatronics System Design PDF

04/09/2024 Fall 2024 MCE 410 - MEE 560 : Mechatronics System Design 1 Chapter 2 Sensors for Mechatronics Sy...

04/09/2024 Fall 2024 MCE 410 - MEE 560 : Mechatronics System Design 1 Chapter 2 Sensors for Mechatronics System Design Maher EL RAFEI, PhD Dept. of Electrical and Computer Engineering maher.elrafei@ lau.edu.lb Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 1 Outline 1. Introduction 2. Sensors Classifications 3. Sensors Characteristics * Range, Span (IFS), OFS, Static transfer function, Accuracy, Precision, Hysteresis, Nonlinearity, Saturation, Dead Band, Resolution, Offset error, Sensitivity, Reliability, Environmental /Application factors, Output Impedance, Output format, Excitation, Uncertainty, Dynamic Characteristics, Ingress Protection (IP) Rating, Calibration. 4. Some Physical Principles of Sensing (Idea) 5. Types of Sensors * Switches (Limit, Temperature, Pressure, Level), Proximity Sensors, Position and Speed Sensors (Ultrasonic, Infrared, Hall effect, LVDT, Potentiometers, Encoders, Tachometers), Light Sensors, Strain Gauge Sensors, Temperature Sensors, Pressure Sensors, Flow Sensors, MEMs, Acceleration Sensors, Accelerometers, Gyroscopes, IMUs, GPS/GNSS, Vision Sensors, SONAR, RADAR, LiDAR, 4-20 mA current loop, Choosing a Sensor. Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 2 1  04/09/2024 Introduction Current idea ! Why do you need Sensors ? Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 3 Introduction Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 4 2  04/09/2024 Introduction ▪ Transducer: is a device that converts energy from one form to another. It can be a sensor or an actuator. Sensor: is an element in a mechatronic or measurement system that detects the magnitude of a physical parameter (measurand or stimulus) and changes it into an electrical signal that can be processed by the system. Monitoring and control systems require sensors to measure physical quantities such as position, velocity, distance (or proximity), force, strain, temperature, vibration, acceleration, pressure, flow, etc. Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 5 Introduction ▪ Positions of Sensors in a Control System ✓ Object: Car, space ship, robot, tank, etc. ✓ Sensor 1, 5: Noncontact (without a physical contact), for example radiation detector and a camera ✓ Sensors 1, 2,3 and 5: Passive (does not need any additional energy source) Thermocouple, photodiode, … ✓ Sensor 4: Active (requires external power for its operation). Thermistor, Resistive Strain Gauge, … ✓ Sensor 5: Internal to DAQ system (internal conditions) ✓ Sensors 1 and 3: Cannot be directly connected to the standard electronic circuits - Inappropriate output signal formats - Require the use of interface devices (signal conditioners) to produce a specific output format Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 6 3  04/09/2024 Outline 1. Introduction 2. Sensors Classifications 3. Sensors Characteristics * Range, Span (IFS), OFS, Static transfer function, Accuracy, Precision, Hysteresis, Nonlinearity, Saturation, Dead Band, Resolution, Offset error, Sensitivity, Reliability, Environmental /Application factors, Output Impedance, Output format, Excitation, Uncertainty, Dynamic Characteristics, Ingress Protection (IP) Rating, Calibration. 4. Some Physical Principles of Sensing (Idea) 5. Types of Sensors * Switches (Limit, Temperature, Pressure, Level), Proximity Sensors, Position and Speed Sensors (Ultrasonic, Infrared, Hall effect, LVDT, Potentiometers, Encoders, Tachometers), Light Sensors, Strain Gauge Sensors, Temperature Sensors, Pressure Sensors, Flow Sensors, MEMs, Acceleration Sensors, Accelerometers, Gyroscopes, IMUs, GPS/GNSS, Vision Sensors, SONAR, RADAR, LiDAR, 4-20 mA current loop, Choosing a Sensor. Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 7 Sensors Classifications Classification of sensors based on their Supply ▪ Active sensors are sensors that require external power source to operate. They are also called parametric sensors because of the dependence of their sensing function on changes in sensor properties (parameters). - Strain gauges (resistance changes as a function of strain), - Thermistors (resistance changes as a function of temperature), - Capacitive or inductive proximity sensors (capacitance or inductance is a function of position) ▪ Passive sensors are sensors that do not require external power sources. These are also called self-generating sensors. They directly generate output response. - Thermocouple, solar cells, piezoelectric sensors (used to measure changes in pressure, temperature, acceleration, strain or force)... Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 8 4  04/09/2024 Sensors Classifications Other Classifications ▪ Based on signal characteristics: Analog or digital. ▪ Based on the subject of measurement: Such subjects include electric, magnetic, mechanical, optical, radiation, thermal, and others. ▪ Absolute or relative sensors: An example of an absolute sensor is a thermistor—a temperature- sensitive resistor. Its electrical resistance directly relates to the absolute temperature scale of Kelvin. Another very popular temperature sensor—a thermocouple—is a relative sensor. It produces an electric voltage that is function of a temperature gradient across the thermocouple wires. Another example: absolute pressure sensor produces signal in reference to vacuum—an absolute zero on a pressure scale. A relative pressure sensor produces signal with respect to a selected baseline that is not zero pressure—for example, to the atmospheric pressure. ▪ Sensors may be classified based on the corresponding application, the corresponding physical phenomena (Thermoelectric, piezoelectric, etc.), the sensor specifications, and others. Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 9 Outline 1. Introduction 2. Sensors Classifications 3. Sensors Characteristics * Range, Span (IFS), OFS, Static transfer function, Accuracy, Precision, Hysteresis, Nonlinearity, Saturation, Dead Band, Resolution, Offset error, Sensitivity, Reliability, Environmental /Application factors, Output Impedance, Output format, Excitation, Uncertainty, Dynamic Characteristics, Ingress Protection (IP) Rating, Calibration. 4. Some Physical Principles of Sensing (Idea) 5. Types of Sensors * Switches (Limit, Temperature, Pressure, Level), Proximity Sensors, Position and Speed Sensors (Ultrasonic, Infrared, Hall effect, LVDT, Potentiometers, Encoders, Tachometers), Light Sensors, Strain Gauge Sensors, Temperature Sensors, Pressure Sensors, Flow Sensors, MEMs, Acceleration Sensors, Accelerometers, Gyroscopes, IMUs, GPS/GNSS, Vision Sensors, SONAR, RADAR, LiDAR, 4-20 mA current loop, Choosing a Sensor. Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 10 5  04/09/2024 Sensors Characteristics Range, Span (IFS), OFS ▪ Range: lowest and highest values of the sensed input. ▪ Span: the arithmetic difference between the highest and lowest values of the sensed input. ▪ Input Full Scale (IFS) = Span ▪ Output Full Scale (OFS) = difference between the upper and lower bounds of the output. Example: A sensor is designed to detect a -50°C to +150 °C temperature and outputs 3.25V to 0.25V ‣Range: -50 °C and +150 °C ‣Span: 150 -(-50)=200 °C ‣IFS = 200 °C ‣OFS = 3.25V –0.25V=3V Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 11 Sensors Characteristics Static Transfer function ▪ A static transfer function represents a relation between the input stimulus s and the electrical signal E produced by the sensor at its output. This relation can be written as E = f(s). ▪ An ideal or theoretical static transfer function exists for every sensor. If a sensor is ideally designed and fabricated with ideal materials by ideal workers working in an ideal environment using ideal tools, the output of such a sensor would always represent the true value of the stimulus. Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 12 6  04/09/2024 Sensors Characteristics Accuracy ▪ A very important characteristic of a sensor is accuracy, which really means inaccuracy. Inaccuracy is measured as a highest deviation of a value represented by the sensor from the ideal or true value of a stimulus at its input. ▪ The accuracy can be defined as a percentage of the IFS or OFS. Example: A thermistor is used to measure temperatures between -30℃ and 80℃ and produces an output voltage between 2.8 V and 1.5 V. The ideal transfer function is shown in the figure below (solid line). - The accuracy in sensing is ±0.5℃ (±0.059𝑉). - As a percentage of the IFS: 0.5 = ∗ 100 = 0.454% (80+30 - As a percentage of the OFS: 0.059 = ∗ 100 = 4.54% (2.8−1.5 Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 13 Sensors Characteristics Precision / Repeatability ▪ Refers to the degree of reproducibility of a measurement. The ability to reproduce the output signal exactly when the same measurand is applied repeatedly under the same environmental conditions. ▪ Accuracy reflects how close a measurement is to a true value, while precision reflects how reproducible measurements are, even if they are far from the accepted value. Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 14 7  04/09/2024 Sensors Characteristics Hysteresis ▪ A sensor should be capable of following the changes of the input parameter regardless of which direction the change is made. ▪ Hysteresis is the deviation of the sensor’s output at any given point when approached from two different directions. It can be defined as a percentage of the Span. Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 15 Sensors Characteristics Nonlinearity ▪ Nonlinearity is defined as the maximum deviation from the ideal linear transfer function. ▪ Nonlinearity is deduced from the actual transfer function of the sensor provided by the manufacturer. It can be defined as a percentage of the Span. ▪ Linearity eliminates the need to do any complex curve fitting and simplifies the calibration process. Saturation ▪ Nonlinearity is defined as the Every sensor has its operating limits. Even if it is considered linear, at some levels of the input stimuli, its output signal no longer will be responsive. Further increase in stimulus does not produce a desirable output. It is said that the sensor exhibits a span-end nonlinearity or saturation. Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 16 8  04/09/2024 Sensors Characteristics Dead Band ▪ Dead band is the insensitivity of a sensor in a specific range of the input signals. In that range, the output may remain near a certain value (often zero) over an entire dead-band zone. Resolution ▪ The smallest detectable incremental change of input parameter that can be detected in the output signal. ▪ In digital systems generally, resolution may be specified as 1/2N (N is the number of bits) Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 17 Sensors Characteristics Offset Error ▪ Offset error of a transducer is defined as the output that will exist when it should be zero. Sensitivity ▪ It is defined as an output voltage change for a given change in input parameter. ▪ For linear transfer functions, sensitivity represents the slope of the curve. A nonlinear transfer function exhibits different sensitivities at different points in intervals of stimuli. In the case of nonlinear transfer functions, sensitivity is defined as a first derivative of the transfer function at the particular stimulus si. where, Δsi is a small increment of the input stimulus and ΔEi is the corresponding change in the sensor output. Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 18 9  04/09/2024 Sensors Characteristics Reliability ▪ A statistical measure of quality of a device indicating the ability to perform its stated function under normal operating conditions without failure for a stated period of time or number of cycles. ▪ Given in hours, years or in Mean Time Between Failure (MTBF). Environmental Factors ▪ Temperature, pressure, humidity, cost, size, weight… Output Impedance Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 19 Sensors Characteristics Output Format Excitation ▪ Excitation is the signal needed to enable operation of an active sensor (Voltage or Current) Uncertainty ui : random and systematic errors Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 20 10  04/09/2024 Sensors Characteristics Dynamic Characteristics ▪ Under the static conditions (a very slow-changing input stimulus) a sensor is described by static transfer function, accuracy, span, calibration, etc. ▪ However, when an input stimulus varies with an appreciable rate, a sensor may be described by a time-dependent characteristic that is called dynamic transfer function. If a sensor is part of a control system, which has its own dynamic characteristics (transfer function in Laplace domain) and has its own bloc in the closed loop bloc diagram. Zero-Order sensor ▪ Characterized by a transfer function that is time independent. Such a sensor does not incorporate any energy storage devices, like a capacitor. A zero-order sensor responds instantaneously. In other words, such a sensors does not need any dynamic characteristics to be specified. Naturally, nearly any sensor still has a finite time to respond, but such time is negligibly short and thus can be ignored. First-Order / Second-Order sensors Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 21 Sensors Characteristics Dynamic Characteristics (Unity step input - First-Order / Second-Order sensors) Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 22 11  04/09/2024 Sensors Characteristics Dynamic Characteristics (Frequency response - First-Order / Second-Order sensors) Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 23 Sensors Characteristics Dynamic Characteristics (First-Order / Second-Order sensors) ▪ The bandwidth is the frequency wB at which the frequency response has declined 3 dB from its low-frequency value. ▪ The Response time indicates the time needed for the output to reach steady state for a step change in input (± 5% or ± 2%). Fast response time is usually desirable (vital if real time feedback is required) Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 24 12  04/09/2024 Sensors Characteristics Ingress Protection (IP) Rating Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 25 Sensors Characteristics Calibration ▪ Calibration is the process of calibrating the indication of a instrument against standard values under specified conditions. Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 26 13  04/09/2024 Sensors Characteristics Calibration Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 27 Sensors Characteristics Calibration Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 28 14  04/09/2024 Sensors Characteristics Calibration Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 29 Sensors Characteristics Calibration Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 30 15  04/09/2024 Outline 1. Introduction 2. Sensors Classifications 3. Sensors Characteristics * Range, Span (IFS), OFS, Static transfer function, Accuracy, Precision, Hysteresis, Nonlinearity, Saturation, Dead Band, Resolution, Offset error, Sensitivity, Reliability, Environmental /Application factors, Output Impedance, Output format, Excitation, Uncertainty, Dynamic Characteristics, Ingress Protection (IP) Rating, Calibration. 4. Some Physical Principles of Sensing (Idea) 5. Types of Sensors * Switches (Limit, Temperature, Pressure, Level), Proximity Sensors, Position and Speed Sensors (Ultrasonic, Infrared, Hall effect, LVDT, Potentiometers, Encoders, Tachometers), Light Sensors, Strain Gauge Sensors, Temperature Sensors, Pressure Sensors, Flow Sensors, MEMs, Acceleration Sensors, Accelerometers, Gyroscopes, IMUs, GPS/GNSS, Vision Sensors, SONAR, RADAR, LiDAR, 4-20 mA current loop, Choosing a Sensor. Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 31 Some Physical Principles of Sensing ▪ Capacitor Another example of a capacitive sensor is a humidity sensor. In such a sensor, a dielectric filling between the capacitor plates is fabricated of a material that is hygroscopic, that is, it can absorb water molecules. The material dielectric constant varies with the amount of absorbed moisture Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 32 16  04/09/2024 Some Physical Principles of Sensing ▪ Induction lA is the volume of a solenoid that often is called G: geometry factor. If a magnetic core is inserted into the inner space of the solenoid, inductance will depend on 3 additional factors: the relative magnetic permeability, μr, of the core material, g, the core geometry factor, and a correction coefficient ηi that is function of the current passing through the solenoid coil having a magnetic core (with no core μr = ηi = 1) Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 33 Some Physical Principles of Sensing ▪ Resistance ▪ Strain changes geometry of conductor and its resistance. ▪ One of the factors that may greatly affect ρ is the amount of humidity that can be absorbed by the resistor (hygristors) Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 34 17  04/09/2024 Some Physical Principles of Sensing ▪ Piezoelectric effect The piezoelectric effect is generation of electric charge by a crystalline material (Quartz SiO2) upon subjecting it to stress. ▪ Pyroelectric effect The pyroelectric materials are crystalline substances capable of generating an electrical charge in response to heat flow. ▪ Hall effect The principle of the Hall effect states that when a current-carrying conductor or a semiconductor is introduced to a perpendicular magnetic field, a voltage can be measured at the right angle to the current path. This effect of obtaining a measurable voltage is known as the Hall effect. Hall Sensors are used to detect magnetic field, position and displacement. ▪ Seebek effect The Seebeck effect is when electricity is created between a thermocouple when the ends are subjected to a temperature difference between them. The Thermoelectric effect occurs when a temperature difference is created between the junctions by applying a voltage difference across the terminals. Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 35 Outline 1. Introduction 2. Sensors Classifications 3. Sensors Characteristics * Range, Span (IFS), OFS, Static transfer function, Accuracy, Precision, Hysteresis, Nonlinearity, Saturation, Dead Band, Resolution, Offset error, Sensitivity, Reliability, Environmental /Application factors, Output Impedance, Output format, Excitation, Uncertainty, Dynamic Characteristics, Ingress Protection (IP) Rating, Calibration. 4. Some Physical Principles of Sensing (Idea) 5. Types of Sensors * Switches (Limit, Temperature, Pressure, Level), Proximity Sensors, Position and Speed Sensors (Ultrasonic, Infrared, Hall effect, LVDT, Potentiometers, Encoders, Tachometers), Light Sensors, Strain Gauge Sensors, Temperature Sensors, Pressure Sensors, Flow Sensors, MEMs, Acceleration Sensors, Accelerometers, Gyroscopes, IMUs, GPS/GNSS, Vision Sensors, SONAR, RADAR, LiDAR, 4-20 mA current loop, Choosing a Sensor. Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 36 18  04/09/2024 Types of Sensors Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 37 Types of Sensors Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 38 19  04/09/2024 Types of Sensors 4 Physical Principle of Sensing 7 Detectors of Humans 8 Presence, Displacement, and Level 9 Velocity and Acceleration 10 Force and Strain 11 Pressure Sensors 12 Flow Sensors 13 Microphones 14 Humidity and Moisture Sensors 15 Light Detectors 16 Detectors of Ionizing Radiation 17 Temperature Sensors 18 Chemical and Biological Sensors Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 39 Switches Limit Switch Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 40 20  04/09/2024 Switches Temperature Switch Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 41 Switches Pressure Switch Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 42 21  04/09/2024 Switches Level Switch Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 43 Proximity Sensors Proximity Sensors Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 44 22  04/09/2024 Proximity Sensors Proximity Sensors Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 45 Proximity Sensors Proximity Sensors Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 23  04/09/2024 Proximity Sensors Proximity Sensors Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors Proximity Sensors Proximity Sensors Most proximity sensors come equipped with an LED status indicator to verify the output switching action. Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 24  04/09/2024 Position & Speed Sensors Position & Speed Sensors Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 49 Position & Speed Sensors Position & Speed Sensors (Ultrasonic) Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 50 25  04/09/2024 Position & Speed Sensors Position & Speed sensors (Ultrasonic) Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 51 Position & Speed Sensors Position & Speed Sensors (Ultrasonic) Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 52 26  04/09/2024 Position & Speed Sensors Position & Speed Sensors (Ultrasonic) Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors Position & Speed Sensors Position & Speed Sensors (Infrared) Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 54 27  04/09/2024 Position & Speed Sensors Position & Speed Sensors (Infrared) Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors Position & Speed Sensors Position & Speed Sensors (Infrared) Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 28  04/09/2024 Position & Speed Sensors Position & Speed Sensors (Infrared) Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors Position & Speed Sensors Position & Speed Sensors ✓ ✓ Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 58 29  04/09/2024 Position & Speed Sensors Position & Speed Sensors (Hall effect) Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 59 Position & Speed Sensors Position & Speed Sensors (Hall effect) Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 60 30  04/09/2024 Position & Speed Sensors Position & Speed Sensors ✓ ✓ ✓ Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 61 Position & Speed Sensors Position & Speed Sensors (LVDT) High Accuracy Less Sensitive to temperature changes Limited displacement Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 62 31  04/09/2024 Position & Speed Sensors Position & Speed measurement sensors (LVDT) Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 63 Position & Speed Sensors Position & Speed measurement sensors (LVDT) Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 64 32  04/09/2024 Position & Speed Sensors Position & Speed Sensors ✓ ✓ ✓ ✓ Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 65 Position & Speed Sensors Position & Speed Sensors (Potentiometers) THE SENSORS POTETIOMETER The potentiometer can be used as displacement or position sensor. This active transducer consists of a uniform coil of wire or a film of high-resistive material—such as carbon, platinum, or conductive plastic— whose resistance is proportional to its length. Practical potentiometer configurations for measuring: (a) Rectilinear motions; (b) Angular motions. Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 33  04/09/2024 Position & Speed Sensors Position & Speed Sensors (Potentiometers) THE SENSORS POTETIOMETER A constant voltage Vref is applied across the coil (or film) using an external dc voltage supply. The transducer output signal V0 is the dc voltage between the movable contact (wiper arm) sliding on the coil and one terminal of the coil. Slider displacement x is proportional to the output voltage: V0 = k.x Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors Position & Speed Sensors Position & Speed Sensors (Encoders) Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 34  04/09/2024 Position & Speed Sensors Position & Speed Sensors (Encoders) Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 69 Position & Speed Sensors Position & Speed Sensors (Absolute Encoders) For example, if there are eight tracks, the encoder is capable of measuring 256 (28) distinct positions corresponding to an angular resolution of 1.406° (360°/256). The most common types of numerical encoding used in the absolute encoder are gray and natural binary codes. To illustrate the action of an absolute encoder, the gray code and natural binary code disk track patterns for a simple four-track (4-bit) encoder are illustrated in the next 2 Figures. Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 70 35  04/09/2024 Position & Speed Sensors Position & Speed Sensors (Absolute Encoders) For example, if there are eight tracks, the encoder is capable of measuring 256 (28) distinct positions corresponding to an angular resolution of 1.406° (360°/256). The most common types of numerical encoding used in the absolute encoder are gray and natural binary codes. To illustrate the action of an absolute encoder, the gray code and natural binary code disk track patterns for a simple four-track (4-bit) encoder are illustrated in the next 2 Figures. Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 71 Position & Speed Sensors Position & Speed Sensors (Relative Encoders) One or two tracks only. May have a third signal which pulses after one complete revolution (used as reference) Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 72 36  04/09/2024 Position & Speed Sensors Position & Speed Sensors (Encoders) Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 73 Position & Speed Sensors Position & Speed Sensors (Tachometers) Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 37  04/09/2024 Light Sensors Light Sensors Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors Strain Gauge Sensors Strain Gauge Sensors Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 38  04/09/2024 Strain Gauge Sensors Strain Gauge Sensors Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors Temperature Sensors Temperature Sensors Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 78 39  04/09/2024 Temperature Sensors Temperature Sensors Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors Temperature Sensors Temperature Sensors Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 80 40  04/09/2024 Temperature Sensors Temperature Sensors Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 81 Pressure Sensors Pressure Sensors Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 82 41  04/09/2024 Types of Sensors Pressure measurement sensors Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 83 Types of Sensors Pressure measurement sensors Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 84 42  04/09/2024 Flow Sensors Flow Sensors Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors Types of Sensors Micro ElectroMechanical Systems (MEMS) Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 86 43  04/09/2024 Types of Sensors Acceleration Sensors Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 87 Types of Sensors Acceleration Sensors Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 88 44  04/09/2024 Types of Sensors Accelerometers Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 89 Types of Sensors Gyroscopes Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 90 45  04/09/2024 Types of Sensors Inertial Measurement Unit (IMU) ▪ IMU is a sensor that uses a combination of accelerometers, gyroscopes and magnetometers to measure acceleration, angular velocity and orientation. A type I IMU consists of accelerometers and gyroscopes. A type II IMU also includes magnetometers. ▪ A typical IMU sensor has 9 DoF (degrees of freedom), including 3-axis accelerometer, 3-axis gyroscope and 3 axis magnetometer. ▪ Some IMUs may have more degrees of freedom, with a temperature sensor, GPS sensor, pressure sensor, etc. ▪ A magnetometer is a device that measures magnetism (direction, strength). A compass is one such device that measures the direction of an ambient magnetic field. In this case, the Earth’s magnetic field. Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 91 Types of Sensors Global Positioning System (GPS) - Global Navigation Satellite System (GNSS) ▪ GPS sensors are receivers with antennas that use a satellite-based navigation system with a network of satellites in orbit around the earth to provide position, velocity, and timing information. Once the receiver receives the signal from at least three satellites, the receiver then points its location (latitude and longitude on a map). The receiver uses four satellites to compute latitude, longitude, altitude, and time. ▪ GNSS is an umbrella term that encompasses all global satellite positioning systems. This includes several constellations of satellites orbiting over the earth’s surface and continuously transmitting signals providing an autonomous geo-spatial positioning with global coverage. ▪ GNSS is used in collaboration with GPS systems where all GNSS receivers are compatible with GPS, but GPS receivers are not necessarily compatible with GNSS. ▪ A GPS receiver has been designed to receive the GPS constellation only (24 satellites) when GNSS- compatible equipment can use navigational satellites from other networks (each network is controlling between 24 and 30 satellites). It is therefore recommended to use GNSS receivers for positioning and timing applications. Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 92 46  04/09/2024 Types of Sensors Vision Sensors Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 93 Types of Sensors Vision Sensors Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 94 47  04/09/2024 Types of Sensors Sound Navigation And Ranging (SONAR) ▪ Sonar, short for Sound Navigation and Ranging, is helpful for exploring and mapping the ocean because sound waves travel farther in the water than do radar and light waves. There are two types of sonar—active and passive. ▪ Active sonar transducers emit an acoustic signal or pulse of sound into the water. If an object is in the path of the sound pulse, the sound bounces off the object and returns an “echo” to the sonar transducer. If the transducer is equipped with the ability to receive signals, it measures the strength of the signal. By determining the time between the emission of the sound pulse and its reception, the transducer can determine the range and orientation of the object. ▪ Passive sonar systems are used primarily to detect noise from marine objects (such as submarines or ships) and marine animals. Unlike active sonar, passive sonar does not emit its own signal, which is an advantage for military vessels that do not want to be found or for scientific missions that concentrate on quietly “listening” to the ocean. Rather, it only detects sound waves coming towards it. Passive sonar cannot measure the range of an object unless it is used in conjunction with other passive listening devices. Multiple passive sonar devices may allow for triangulation of a sound source. Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 95 Types of Sensors Radio Detecting and Ranging (RADAR) ▪ Electromagnetic sensor used for detecting, locating, tracking, and recognizing objects of various kinds at considerable distances. It operates by transmitting electromagnetic energy toward objects, commonly referred to as targets, and observing the echoes returned from them ▪ A Doppler radar is a specialized radar that uses the Doppler effect to produce velocity data about objects at a distance. It does this by bouncing a microwave signal off a desired target and analyzing how the object's motion has altered the frequency of the returned signal. This variation gives direct and highly accurate measurements of the radial component of a target's velocity relative to the radar. The term applies to radar systems in many domains like aviation, police radar detectors, navigation, meteorology, etc. ▪ Some Applications: military, space exploration, remote sensing, aircraft navigation, ship Navigation, … Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 96 48  04/09/2024 Types of Sensors LiDAR Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 97 Types of Sensors LiDAR Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 98 49  04/09/2024 Types of Sensors LiDAR Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 99 Types of Sensors LiDAR Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 100 50  04/09/2024 Types of Sensors 4-20 mA current loop industrial standard Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 101 Types of Sensors 4-20 mA current loop industrial standard Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 102 51  04/09/2024 Types of Sensors 4-20 mA current loop industrial standard Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 103 Types of Sensors 4-20 mA current loop industrial standard Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 104 52  04/09/2024 Types of Sensors 4-20 mA current loop industrial standard Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 105 Types of Sensors Choosing a Sensor Maher El Rafei LAU – SOE, MCE 410 - MEE 560: Mechatronics System design 1 – Chap 2 - Sensors 106 53