Big data and IOT are crucial concept in the Industry 4.0 framework and the the rapid evolution of measurement instrumentation is changing the way in which measurements are performed. The recent developments in the field of sensors enable the description of physical phenomena at incredibly low cost. As a matter of fact, the developments of novel sensors, data acquisition techniques and data analysis procedures implies the necessity of deep metrological knowledges for an automation engineer. 

The teaching aims at helping the students in the selection of the proper transducers for mechanical and thermal control applications, by describing the main categories of mechanical and thermal instrumentation from both a theoretical and a practical point of view. Instead of describing the sensors that nowadays can be used for different application, the teaching will be focused on the identification of the generic properties of instruments that can be used to select and compare the optimal instrumentation. In this way, the student will be prepared to face the rapid evolution that is characterizing the world of metrology in industry 4.0 era.

At the end of the teaching, the student is expected to reach the following learning outcomes

Knowledge and comprehension

• Traceability and calibration
• measurement uncertainty
• Metrology

Ability in the application of knowledge

• prepare a setup for the acquisition of data coming from the most common measurement instruments
• compute the measurement uncertainty in accordance with the ISO GUM
• to design fit-to-purpose measurement chains for specific mechanical and thermal applications

Authonomy in judgement

• select the best trasducer for the majority of mechanical and thermal measurements.
• compare two similar transducers by analyzing their datasheet and their metrological characteristics
• identify the correct calibration procedure for the majority of mechanical and thermal sensors

• Students that decide to present the project instead of the written exam will learn how to work in team and how to present the results of a project 

Generalized performances of measurement instruments
Uncertainty; Static and dynamic performances of measurement instruments; generalized theory of measurement instruments; load effect.
Fourier Analysis; dynamic performances of measurement systems; time response of first- and second-order systems. Experimental identification of response of first- and second-order systems

Strain measurements
Introduction to strain gauges; calibration, Wheatstone bridge measurement circuits; compensation of thermal effects and improvement of sensitivity.

Displacement and rotation transducers
Resistive, LVDT, inductive; non-contact transducers (eddy current, capacitive. Mounting of displacement transducers. Vision systems. Angular displacement and velocity transducers (potentiometers, RVDT, encoder). 

Non-contact vibration transducers: Laser triangulation sensors; Time of Flight lasers and Cameras, Laser Doppler vibrometers and interferometers; cameras for 2D and 3D machine vision applications; most common algorithms for machine vision

Vibration measurements.
Short introduction to the displacement, velocity and acceleration of mechanical systems. Criteria for the selection of transducers. Absolute transducers (accelerometers and seismometers); piezoelectric and IEPE sensors, MEMS accelerometers. Fixation of vibration pickups according to the ISO 5348.

Force and pressure measurements
Piezoelectric, elastic and strain-gauge based load cells and pressure transducers. Static and dynamic calibration of force and pressure transducers

Temperature measurements
Thermal resistances, Thermistors, thermocouples, infra-red thermometers. Dual-color pyrometer. IR cameras. experimental identification of emissivity 
 

Each topic is treated theoretically in a classroom lecture. In the following laboratory experience, students can use the different measurement instruments and analyse the experimental data according to the procedures learned during the theoretical lectures. 

The course prerequisites are:

• deep knowledge of electromagnetism (ohm generalized law, lumped parameter electrical systems, capacitors, electrical resistance, inductance, eddy currents)
• good knowledge of statistics (descriptive statistics, probability density, cumulative probability density, confidence intervals, central limit theorem);
• basic concept of mechanics (kinematics, dynamics, displacement, acceleration, velocity)
• basic concepts of material science (stress, strain, poisson ratio, young modulus, De Saint Venant beam)
• basic concepts of heat transfer
• basic programming skills in Excel, Matlab and Labview

Given the low number of teaching hours, there will be no mid-term exam. The exam is composed by a written part (traditional exam or project) and an oral part. 

Written
The written part is typically a random composition of 2 exercises and 3-4 theoretical questions taken from the PDF “exercises” downloadable from BEEP. Said N the total number of questions + exercises, each correct question gives you 30/N points.
The written is sufficient (and therefore you can access the oral exam) only if you get more than 18/30

Project
The written can be substituted by a project focused on the topic of the labs. In the project, you must develop your own acquisition system, perform some measurements and show us that you are able to choose a sensor and to use it for some practical courses. The project gives you, at most, 10/30 and the oral is mandatory

Oral

The oral exam is mandatory for everybody. If the marks of all the questions of the written are similar, the oral will be focused on the discussion of the written exam. There can be, at most, 2 theoretical questions, worthing 30/N points each. Said AQ the number of additional questions and MAQ the sum of the marks that you get in the additional questions, the final mark will be normalized as follows
Mark = (written mark+MAQ)/(30/N)*(N+NAQ)