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M. De Cecco - Lucidi del corso di Measurement Systems and Applications Measurement Systems and Applications Mariolino De Cecco Antonio Selmo Michele Confalonieri.

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Presentation on theme: "M. De Cecco - Lucidi del corso di Measurement Systems and Applications Measurement Systems and Applications Mariolino De Cecco Antonio Selmo Michele Confalonieri."— Presentation transcript:

1 M. De Cecco - Lucidi del corso di Measurement Systems and Applications Measurement Systems and Applications Mariolino De Cecco Antonio Selmo Michele Confalonieri

2 M. De Cecco - Lucidi del corso di Measurement Systems and Applications Force Panel The instrument employed

3 M. De Cecco - Lucidi del corso di Measurement Systems and Applications How its electronics work? [Antonio Selmo] How its electronics work? [Antonio Selmo] Design and purpose of the FP [a couple of frontal lessons] Design and purpose of the FP [a couple of frontal lessons] Measurements for Diagnostics [study and identification of the HTF] Measurements for Diagnostics [study and identification of the HTF] Principles of human diagnosis and rehabilitation [doct Guandalini and Tomasi] Principles of human diagnosis and rehabilitation [doct Guandalini and Tomasi] Achronims: Fprce Panel – FP Human Transfer Function - HTF Logic of the Course Rehabilitation and its quantification (measure of indexes of performance) [development of serious games with processing]

4 M. De Cecco - Lucidi del corso di Measurement Systems and Applications Application: identification of human transfer function for dexterity assessment and serious games for rehabilitation Method: - study of touch technology - study of signal analog elaboration and conversion - acquisition of human data - signal processing Course: - frontal lessons (few) - exercitation with matlab - building of the application with Processing - visit to a clinic Exam: - oral discussion - homework Material of the course can be found at Organization and final examination

5 M. De Cecco - Lucidi del corso di Measurement Systems and Applications VERITAS Project Project number: Project acronym: VERITAS Project full title: Virtual and Augmented Environments and Realistic User Interactions To achieve Embedded Accessibility DesignS Site: Starting date: 1 January 2010 Duration: 48 Months VERITAS is an Integrated Project (IP) within the 7th Framework Programme, Theme FP7- ICT , Accessible and Assistive ICT

6 M. De Cecco - Lucidi del corso di Measurement Systems and Applications Design and purpose of the FP - VERITAS Project Virtual and Augmented Environments and Realistic User Interactions To achieve Embedded Accessibility DesignS Method SP1: development of virtual users SP2: development of the simulation platform SP3: validation OBJECTIVE develop virtual humans for accessibility design in virtual simulation of ICT and non ICT products UNITN activities Modeling Measurement

7 M. De Cecco - Lucidi del corso di Measurement Systems and Applications Systems developed: –Garment based Motion Capture: Ga-MoCap –Multi-axis load cell –Force Panel VERITAS Project - measurement systems developed

8 M. De Cecco - Lucidi del corso di Measurement Systems and Applications Diagnostics by human dexterity estimation Requirements: –Measure position of the touch –Measure the applied force –Store the above for path and trajectories –Accuracy and sampling frequency able to reveal human dexterity –Visual feedback Idea: Force Panel –Display LCD –Touch panel –Force transducers Design and purpose of the FP - requirements

9 M. De Cecco - Lucidi del corso di Measurement Systems and Applications Stato dellarte Touch screen LCD and cameras Graph tablets Design and purpose of the FP - state of the art

10 M. De Cecco - Lucidi del corso di Measurement Systems and Applications Stato dellarte joystick Aptics devices and virtual reality Design and purpose of the FP - state of the art

11 M. De Cecco - Lucidi del corso di Measurement Systems and Applications Force Panel Design and purpose of the FP - Design

12 M. De Cecco - Lucidi del corso di Measurement Systems and Applications Schema della struttura (disposizione dei vincoli) Horizontal useVertical use = perpendicular to LCD = parallel to LCD 3 load cells Design and purpose of the FP - Design

13 M. De Cecco - Lucidi del corso di Measurement Systems and Applications Tipologie di vincolo considerate –Spherical joints –wires 2 solutions ! Design and purpose of the FP - Design

14 M. De Cecco - Lucidi del corso di Measurement Systems and Applications Design and purpose of the FP - Design

15 M. De Cecco - Lucidi del corso di Measurement Systems and Applications Variante con teste a snodo mechanical design: spherical joint

16 M. De Cecco - Lucidi del corso di Measurement Systems and Applications mechanical design: wires

17 M. De Cecco - Lucidi del corso di Measurement Systems and Applications mechanical design: wires constraints

18 M. De Cecco - Lucidi del corso di Measurement Systems and Applications mechanical design: wires constraints

19 M. De Cecco - Lucidi del corso di Measurement Systems and Applications Requirements: No buckling No finger force through the blues Diameter 1 mm Wires with load cell –Length 10 mm (due to physical constraints) wires –Length 30 mm (FEM analysis finger force < 0.3 %) F mechanical design: wires length

20 M. De Cecco - Lucidi del corso di Measurement Systems and Applications Lunghezza dei fili horizontalVertical Worst case for bucklingWorst case for force leakage mechanical design: wires length

21 M. De Cecco - Lucidi del corso di Measurement Systems and Applications Critical length 65 mm Force lost: Moments – Nm CasoErrore lettura forza [%] Worst case horizontal, l = 10 mm2.41 Worst case vertical, l = 10 mm2.50 Worst case for buckling, l = 10 mm5.32 Worst case for buckling, l = 20 mm0.73 Worst case for buckling, l = 30 mm0.22 Worst case for buckling, l = 30 mm, e = 0.5 mm0.23 Worst case for buckling, l = 30 mm, e = 1 mm0.27 mechanical design: wires length

22 M. De Cecco - Lucidi del corso di Measurement Systems and Applications VGA Force Conditio ning 3 x ANALOG IN USB 2 x DIGITAL OUT Touch panel Force sensors µController PC 2 x ANALOG IN LCD System design: overall layout

23 M. De Cecco - Lucidi del corso di Measurement Systems and Applications Touch position measurement circuit A touch screen is a 2-dimensional sensing device constructed of 2 sheets of material separated slightly by spacers A common construction is a sheet of glass providing a stable bottom layer and a sheet of Polyethylene (PET) as a flexible top layer The 2 sheets are coated with a resistive substrate, usually a metal compound called Indium Tin Oxide (ITO). The ITO is thinly and uniformly sputtered onto both the glass and the PET layer Tiny spacers are placed between the 2 sheets in order to prevent false touch When the PET film is pressed the two resistive surfaces meet. This position can be read as illustrated in next slides

24 M. De Cecco - Lucidi del corso di Measurement Systems and Applications Indium tin oxide (ITO, or tin-doped indium oxide) is a solid solution of indium(III) oxide (In2O3) and tin(IV) oxide (SnO2), typically 90% In2O3, 10% SnO2 by weight. It is transparent and colorless in thin layers while in bulk form it is yellowish to grey. In the infrared region of the spectrum it is a metal-like mirror. Indium tin oxide is one of the most widely used transparent conducting oxides because of its two chief properties: - its electrical conductivity - optical transparency Touch position measurement circuit

25 M. De Cecco - Lucidi del corso di Measurement Systems and Applications 5 V GND V S - sense L y+ R 0 is the total resistance of the substrate R T is the touch resistance Touch position measurement circuit

26 M. De Cecco - Lucidi del corso di Measurement Systems and Applications Reading the x coordinate is similar Note that in the equivalent circuit there are capacitive effects that lead to a certain delay that usually is less than 10 ms Touch position measurement circuit

27 M. De Cecco - Lucidi del corso di Measurement Systems and Applications Electronics scheme

28 M. De Cecco - Lucidi del corso di Measurement Systems and Applications Alim. cella Output cella Alim. condiz. ( ± 15 V DC) Circuito di condizionamento Pre- Amplificazione e Filtro analogico passa basso Bessel V ordine Pre- Amplificazione e Filtro analogico passa basso Bessel V ordine DC / DC Alimentazione (12 V DC) Cella di carico μCμC μCμC Shift del segnale (μC legge solo tensioni positive) Shift del segnale (μC legge solo tensioni positive) Amplificazione Conditioning unit

29 M. De Cecco - Lucidi del corso di Measurement Systems and Applications Conditioning unit

30 M. De Cecco - Lucidi del corso di Measurement Systems and Applications Bessel lowpass 5° order Gain and offset adjustment: Arduino reads only positive voltages (0 – 5 V) Full Wheatstone bridge Conditioning unit

31 M. De Cecco - Lucidi del corso di Measurement Systems and Applications RISPOSTA TEMPORALE AL GRADINO DEL FILTRO PASSA BASSO DEL 5° ORDINE (Risposta di Bessel con frequenza di taglio 1 kHz) 20 s 50 s Tempo di assestamento No sovraelongation 500 s Conditioning unit

32 M. De Cecco - Lucidi del corso di Measurement Systems and Applications Arduino UNO X Y F1 F2 F3 Alimentazione lungo X Attesa assestamento circuito RC Lettura valore X Alimentazione lungo Y Attesa assestamento circuito RC Lettura valore Y Lettura valore F1 Lettura valore F2 Lettura valore F3 PC Inizializzazioni (costanti, variabili e pin μC) Inizializzazioni (costanti, variabili e pin μC) sw design: embedded system

33 M. De Cecco - Lucidi del corso di Measurement Systems and Applications PIN per lettura X TASK 2 – PC TASK 3 – PC Ricezione dati ed applicazione modello di taratura Gestione delle immagini in relazione alle risposte di chi sta di fronte al pannello TASK 1 – Arduino t assest. RC Read X PIN per lettura Y Read F1, F2, F3 nel t assest. RC Read Y Invio dati via RS t [ms] task paralleli su PC: - uno segue lArduino, - uno è indipendente sw design: task analysis

34 M. De Cecco - Lucidi del corso di Measurement Systems and Applications Acquisition Inizializzazioni Lettura RS-232 Riconoscimento stringa Distinzione segnali Eventuali operazioni di filtraggio Operazioni di taratura Elaboration and graphical output Inizializzazioni Attesa inizio acquisizione Calcolo della tara del sistema Elaborazione (gestione delle immagini in relazione allinterazione con lutente) sw design: two independent tasks on the PC

35 M. De Cecco - Lucidi del corso di Measurement Systems and Applications 1.Touch position (resistive touch) 2.Force (load cell) 3.Touch position (load cell) Calibration

36 M. De Cecco - Lucidi del corso di Measurement Systems and Applications Force Panel - calibration

37 M. De Cecco - Lucidi del corso di Measurement Systems and Applications Measurement model: Linear behaviour on both directions No interactions uncoupled modelling x m [pixel] y m [pixel] x m = f (x a ) y m = f (y a ) x m = f (x a ) y m = f (y a ) x a [bit] y a [bit] calibration: position

38 M. De Cecco - Lucidi del corso di Measurement Systems and Applications Non-linear behaviour for: –Touch position –Force F T [bit] F m [N] F m [N] = f (F a, x m, y m ) x m [pixel] y m [pixel] calibration: force

39 M. De Cecco - Lucidi del corso di Measurement Systems and Applications For N measurements made in different positions and with different forces it is possible to build the following linear relation Than, with a pseudoinverse computation, the 10 coefficients of the polynomial model are estimated WORK IN CLASS Force Panel - calibration: force

40 M. De Cecco - Lucidi del corso di Measurement Systems and Applications The pseudoinverse computation gives the 10 coefficients of the polynomial model: NOTE: A T A is generally a square and full rank matrix WORK IN CLASS Force Panel - calibration: force

41 M. De Cecco - Lucidi del corso di Measurement Systems and Applications WORK IN CLASS Force Panel - calibration: force Files given: - read_float.m How to use read_float : jj = 1 ; % numero file file = ['dati_celle_armon_', num2str(jj), '.txt'] ; dati = read_float(file, ',', ':') ; clc Dati = cell2mat(dati); % grammi -> Newton Dati(:,1) = Dati(:,1)*(9.81/1000) ;

42 M. De Cecco - Lucidi del corso di Measurement Systems and Applications % Data are saved on 9 files dati_celle_armon_1…9.txt As follows on columns: % 1 -> calibration load [g] % 2 -> x position [pixel] % 3 -> y position [pixel] % 4 -> load cell 1 (in alto) [N] % 5 -> load cell 2 (in basso a sx) [N] % 6 -> load cell 1 (in basso a dx) [N] % 7 -> load cell sum [N] WORK IN CLASS Force Panel - calibration: force

43 M. De Cecco - Lucidi del corso di Measurement Systems and Applications chi2gof Chi-square goodness-of-fit test on the vector Performs a chi-square goodness-of-fit test for discrete or continuous distributions. The test is performed by grouping the data into bins, calculating the observed and expected counts for those bins, and computing the chi-square test statistic SUM((O- E).^2./E), where O is the observed counts and E is the expected counts. This test statistic has an approximate chi-square distribution when the counts are large. WORK IN CLASS Force Panel - calibration: force

44 M. De Cecco - Lucidi del corso di Measurement Systems and Applications WORK IN CLASS Force Panel - calibration: force Procedure: 1.With the pseudoinverse computation estimate the 10 coefficients of the proposed polynomial model taking one data file at your choice 2.Apply the estimated coefficients to the model to predict (validate) the model behaviour using a different data file 3.Analyse the residuals and the validation behaviour 4.Apply the chi2gof test to verify the randomness of the residuals 5.Try to choose different mathematical models and see how the chi2gof test performs

45 M. De Cecco - Lucidi del corso di Measurement Systems and Applications F 1a [bit] x m = f (F 1a, F 2a, F 3a ) y m = f (F 1a, F 2a, F 3a ) x m = f (F 1a, F 2a, F 3a ) y m = f (F 1a, F 2a, F 3a ) F 2a [bit] F 3a [bit] x m [pixel] y m [pixel] Force Panel – calibration position

46 M. De Cecco - Lucidi del corso di Measurement Systems and Applications ResolutionAccuracy Position X [mm]< 0.40± 1.80 (al 95%) Position Y [mm]< 0.30± 1.80 (al 95%) Force [N]< 0.05± 0.10 (al 95%) Time [ms]10± 5 Nail Finger finger horizontal Yellow:resistive touch Blue:load cell reconstruction Force Panel – calibration position

47 M. De Cecco - Lucidi del corso di Measurement Systems and Applications


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