Progetto del terzo anno del Propedeutico di Meccanica al Polimi con Federico Perotti:
- modellazione del telaio e impostazione dei carichi esterni in condizioni di accelerazione e decelerazione
- scrittura del file di input e risoluzione mediante codice Matlab che sfrutta il metodo degli Spostamenti
- dimensionamento di massima dei tubi del telaio
- considerazioni
Progetto del terzo anno del Propedeutico di Meccanica al Polimi con Federico Perotti:
- modellazione del telaio e impostazione dei carichi esterni in condizioni di accelerazione e decelerazione
- scrittura del file di input e risoluzione mediante codice Matlab che sfrutta il metodo degli Spostamenti
- dimensionamento di massima dei tubi del telaio
- considerazioni
Optimization of the welding parameters in resistance spot weldingIAEME Publication
This document summarizes an analysis of resistance spot welding parameters on CRCA steel sheets using Taguchi methods. The authors conducted experiments varying welding current, electrode force, and welding time according to an L9 orthogonal array. Tensile shear strength was evaluated as the output parameter. Analysis of variance found welding current to be the most influential parameter, contributing 49.72% to strength. Optimal parameters were determined to be high current of 13.5 kA, medium electrode force of 4 kN, and high welding time of 10 seconds. Taguchi methods allowed determination of optimal resistance spot welding parameters for maximum tensile shear strength.
This document provides guidelines for spot welding SCS processed steel. Testing showed that SCS steel is suitable for resistance welding and has better weldability than hot-rolled black steel. Spot welding SCS requires regular electrode cleaning to prevent oxide buildup. Electrode life is equivalent when welding SCS or hot-rolled pickled and oiled steel. The document provides starting parameters for resistance spot welding SCS steel and general rules for making good spot welds. Electrical resistivity testing showed SCS has similar resistivity to hot-rolled pickled and oiled steel and less than hot-rolled black steel.
Advanced Modeling & Simulation Techniques for Multibody Robotic SystemsDesign World
This webinar introduces new techniques and case studies for efficiently increasing the fidelity of system models for multibody robotic system design. Using symbolic computation techniques, multibody models can be effectively preprocessed to select optimal coordinate frames, eliminate redundant calculations, simplify algebraic constraints, and generate computationally minimal code for real-time deployment. Furthermore, novel mathematical techniques can be deployed for efficient parameter optimization and other advanced analysis.
Applications in robotics, including space and industrial robotics will be presented. The symbolic computation system Maple and the related modeling system MapleSim will be used to illustrate examples.
Attend this webinar to learn:
– How symbolic formulations can increase simulation speed without reducing model fidelity
– How high fidelity models can accelerate design time, reduce costly design errors, and ultimately improve the functional performance of robotics systems
Optimization of resistance spot welding parameters for welding of stainless ...Alexander Decker
This document presents a study on optimizing resistance spot welding parameters for joining austenitic stainless steel AISI 301L sheets using the Taguchi method. Indentation, nugget diameter, tensile strength, and penetration were evaluated. Experiments were conducted using an L32 orthogonal array to analyze welding current, weld cycle, hold time, and cool time. Analysis of variance identified weld cycle, interaction of welding current and weld cycle, and interaction of welding current, weld cycle, and hold time as significant factors affecting indentation. Validation experiments at the optimized levels showed indentation decreased by over 50% while tensile strength, nugget diameter, and penetration met standards. The Taguchi method was effective for
1. The document discusses forward kinematics of robot manipulators. It defines key concepts like links, joints, Denavit-Hartenberg parameters, and homogeneous transformation matrices.
2. The forward kinematics problem is solved by assigning coordinate frames to each link and determining the transformation between frames using link variables and homogeneous transformations.
3. The position and orientation of the end effector is determined by multiplying the homogeneous transformation matrices representing each link transformation.
Training and Simulation in a More Autonomous and Robotic FutureAndy Fawkes
Training and Simulation in a More Autonomous and Robotic Future - Presented at Royal Aeronautical Society Conference - The Future of Flight Training Devices - RAeS London UK - 12 November 2014
Spot welding is a metal joining process where two metal surfaces are welded together by resistance heating when a large current is passed through them. The current causes the metal to heat up and melt together. It allows for quick and easy welding of multiple metal sheets simultaneously without filler metals or flames. However, spot welds have lower strength than other weld types and repairs can be difficult. It is commonly used in the automobile industry to join metal car body panels and parts.
This document provides a 23-page overview of resistance spot welding of aluminium and its alloys. It discusses:
1) The suitability of aluminium alloys for spot welding and how the surface condition, chemical composition, and metallurgical condition affect it.
2) The different physical properties of aluminium compared to steel that influence the spot welding process, such as higher electrical and thermal conductivity in aluminium.
3) Key factors in spot welding aluminium like the oxide film that must be removed, various surface pretreatment methods, and machine parameters that differ from steel due to aluminium's properties.
Prateek Sood completed an industrial training at VEEGEE KAUSHICKO ENGINEERING PVT. LTD. The training focused on learning about robotic welding through teaching programming, installations, cell design, and hands-on work. During the training, Prateek learned robotic functionality, welding machine basics, robot teaching, PLC programming, and production calculations. The training helped develop practical skills and confidence needed to work in the robotics and manufacturing field.
The document discusses various types of tooling used for joining processes like welding, brazing and soldering. It describes different considerations for designing fixtures for gas welding, arc welding and resistance welding. Fixtures need to hold parts in proper alignment, allow for heat control and prevent distortion. Materials must withstand high temperatures and properly direct heat flow. The document also discusses workholding principles and tooling designs for CNC machines.
These slide gives overall welding process and gives the tips about the robotic welding process and then adaptability with the industrial welding robotic coordinates.
The use of jigs and fixtures within manufacturing is widely employed. Their design and the parameters to be taken in to account are discussed with the aid of a case study.
Robot Welding is a process of joining different materials.
The large bulk of materials that are welded are metals and their alloys although welding is also applied to the joining of other materials such as thermoplastics.
The document discusses various types of automation in welding processes including manual, semi-automatic, automatic, automated, remote, and robotic welding. It describes the key stages in a welding operation sequence and provides examples of different techniques used for automation in welding applications from the 1920s to present day. Specific automation techniques are highlighted for different welding processes based on factors like production volume and part geometry.
The document discusses forward kinematics, which is finding the position and orientation of the end effector given the joint angles of a robot. It covers different types of robot joints and configurations. It introduces the Denavit-Hartenberg coordinate system for defining the relationship between successive links of a robot. The document also discusses forward kinematic calculations, inverse kinematics, robot workspaces, and trajectory planning.
This document provides an introduction and syllabus for a robotics course. It will cover topics like locomotion, perception, planning and navigation. Students will gain hands-on experience through simulation exercises and programming robots. They will also participate in an online robot soccer competition. The course aims to teach the science and challenges of robotics through both theoretical lectures and practical assignments using a robot simulation program called Webots.
1) The document discusses the fundamentals of robotic manipulators, including their classification, parts, motions, and work envelopes.
2) The major types of robot configurations are Cartesian, cylindrical, spherical, SCARA, and articulated, which are defined by their joint types and resulting work spaces.
3) Robotic manipulators consist of links connected by joints and powered by electric, hydraulic, or pneumatic drives to position an end effector through programmed motions.
This document compares different spot welding systems: DC, AC transformer gun, and AC portable gun. It finds that the DC system provides more stable weld quality, higher power/utilities savings due to a higher power factor and energy efficiency. The DC welding transformer is smaller in size and weight compared to the AC transformer gun. Mathematical equations are also presented for calculating welding parameters like current and time based on factors like material properties, plate thickness, and required nugget size.
6° Presentazione del workshop finale del progetto EFFICITY
Sviluppo di strategie di gestione ottimale di reti complesse di distribuzione dell'energia
Sito web del progetto: www.efficity-project.it
Optimization of the welding parameters in resistance spot weldingIAEME Publication
This document summarizes an analysis of resistance spot welding parameters on CRCA steel sheets using Taguchi methods. The authors conducted experiments varying welding current, electrode force, and welding time according to an L9 orthogonal array. Tensile shear strength was evaluated as the output parameter. Analysis of variance found welding current to be the most influential parameter, contributing 49.72% to strength. Optimal parameters were determined to be high current of 13.5 kA, medium electrode force of 4 kN, and high welding time of 10 seconds. Taguchi methods allowed determination of optimal resistance spot welding parameters for maximum tensile shear strength.
This document provides guidelines for spot welding SCS processed steel. Testing showed that SCS steel is suitable for resistance welding and has better weldability than hot-rolled black steel. Spot welding SCS requires regular electrode cleaning to prevent oxide buildup. Electrode life is equivalent when welding SCS or hot-rolled pickled and oiled steel. The document provides starting parameters for resistance spot welding SCS steel and general rules for making good spot welds. Electrical resistivity testing showed SCS has similar resistivity to hot-rolled pickled and oiled steel and less than hot-rolled black steel.
Advanced Modeling & Simulation Techniques for Multibody Robotic SystemsDesign World
This webinar introduces new techniques and case studies for efficiently increasing the fidelity of system models for multibody robotic system design. Using symbolic computation techniques, multibody models can be effectively preprocessed to select optimal coordinate frames, eliminate redundant calculations, simplify algebraic constraints, and generate computationally minimal code for real-time deployment. Furthermore, novel mathematical techniques can be deployed for efficient parameter optimization and other advanced analysis.
Applications in robotics, including space and industrial robotics will be presented. The symbolic computation system Maple and the related modeling system MapleSim will be used to illustrate examples.
Attend this webinar to learn:
– How symbolic formulations can increase simulation speed without reducing model fidelity
– How high fidelity models can accelerate design time, reduce costly design errors, and ultimately improve the functional performance of robotics systems
Optimization of resistance spot welding parameters for welding of stainless ...Alexander Decker
This document presents a study on optimizing resistance spot welding parameters for joining austenitic stainless steel AISI 301L sheets using the Taguchi method. Indentation, nugget diameter, tensile strength, and penetration were evaluated. Experiments were conducted using an L32 orthogonal array to analyze welding current, weld cycle, hold time, and cool time. Analysis of variance identified weld cycle, interaction of welding current and weld cycle, and interaction of welding current, weld cycle, and hold time as significant factors affecting indentation. Validation experiments at the optimized levels showed indentation decreased by over 50% while tensile strength, nugget diameter, and penetration met standards. The Taguchi method was effective for
1. The document discusses forward kinematics of robot manipulators. It defines key concepts like links, joints, Denavit-Hartenberg parameters, and homogeneous transformation matrices.
2. The forward kinematics problem is solved by assigning coordinate frames to each link and determining the transformation between frames using link variables and homogeneous transformations.
3. The position and orientation of the end effector is determined by multiplying the homogeneous transformation matrices representing each link transformation.
Training and Simulation in a More Autonomous and Robotic FutureAndy Fawkes
Training and Simulation in a More Autonomous and Robotic Future - Presented at Royal Aeronautical Society Conference - The Future of Flight Training Devices - RAeS London UK - 12 November 2014
Spot welding is a metal joining process where two metal surfaces are welded together by resistance heating when a large current is passed through them. The current causes the metal to heat up and melt together. It allows for quick and easy welding of multiple metal sheets simultaneously without filler metals or flames. However, spot welds have lower strength than other weld types and repairs can be difficult. It is commonly used in the automobile industry to join metal car body panels and parts.
This document provides a 23-page overview of resistance spot welding of aluminium and its alloys. It discusses:
1) The suitability of aluminium alloys for spot welding and how the surface condition, chemical composition, and metallurgical condition affect it.
2) The different physical properties of aluminium compared to steel that influence the spot welding process, such as higher electrical and thermal conductivity in aluminium.
3) Key factors in spot welding aluminium like the oxide film that must be removed, various surface pretreatment methods, and machine parameters that differ from steel due to aluminium's properties.
Prateek Sood completed an industrial training at VEEGEE KAUSHICKO ENGINEERING PVT. LTD. The training focused on learning about robotic welding through teaching programming, installations, cell design, and hands-on work. During the training, Prateek learned robotic functionality, welding machine basics, robot teaching, PLC programming, and production calculations. The training helped develop practical skills and confidence needed to work in the robotics and manufacturing field.
The document discusses various types of tooling used for joining processes like welding, brazing and soldering. It describes different considerations for designing fixtures for gas welding, arc welding and resistance welding. Fixtures need to hold parts in proper alignment, allow for heat control and prevent distortion. Materials must withstand high temperatures and properly direct heat flow. The document also discusses workholding principles and tooling designs for CNC machines.
These slide gives overall welding process and gives the tips about the robotic welding process and then adaptability with the industrial welding robotic coordinates.
The use of jigs and fixtures within manufacturing is widely employed. Their design and the parameters to be taken in to account are discussed with the aid of a case study.
Robot Welding is a process of joining different materials.
The large bulk of materials that are welded are metals and their alloys although welding is also applied to the joining of other materials such as thermoplastics.
The document discusses various types of automation in welding processes including manual, semi-automatic, automatic, automated, remote, and robotic welding. It describes the key stages in a welding operation sequence and provides examples of different techniques used for automation in welding applications from the 1920s to present day. Specific automation techniques are highlighted for different welding processes based on factors like production volume and part geometry.
The document discusses forward kinematics, which is finding the position and orientation of the end effector given the joint angles of a robot. It covers different types of robot joints and configurations. It introduces the Denavit-Hartenberg coordinate system for defining the relationship between successive links of a robot. The document also discusses forward kinematic calculations, inverse kinematics, robot workspaces, and trajectory planning.
This document provides an introduction and syllabus for a robotics course. It will cover topics like locomotion, perception, planning and navigation. Students will gain hands-on experience through simulation exercises and programming robots. They will also participate in an online robot soccer competition. The course aims to teach the science and challenges of robotics through both theoretical lectures and practical assignments using a robot simulation program called Webots.
1) The document discusses the fundamentals of robotic manipulators, including their classification, parts, motions, and work envelopes.
2) The major types of robot configurations are Cartesian, cylindrical, spherical, SCARA, and articulated, which are defined by their joint types and resulting work spaces.
3) Robotic manipulators consist of links connected by joints and powered by electric, hydraulic, or pneumatic drives to position an end effector through programmed motions.
This document compares different spot welding systems: DC, AC transformer gun, and AC portable gun. It finds that the DC system provides more stable weld quality, higher power/utilities savings due to a higher power factor and energy efficiency. The DC welding transformer is smaller in size and weight compared to the AC transformer gun. Mathematical equations are also presented for calculating welding parameters like current and time based on factors like material properties, plate thickness, and required nugget size.
6° Presentazione del workshop finale del progetto EFFICITY
Sviluppo di strategie di gestione ottimale di reti complesse di distribuzione dell'energia
Sito web del progetto: www.efficity-project.it
Presentation of Massimo Talia's Master Degree Dissertation in Electronic Engineering, the developer of ICT perspectives.
------------------------------------------------------------------------------
Presentazione della Tesi di laurea in Ingegneria Elettronica di Massimo Talia, lo sviluppatore di ICT perspectives.
Automation Engineering: Solved Models - Raccolta di modelli risoltiAndrea Tino
A collection of solved mathematical models regarding the most important controlled systems in Automation Engineering. Written during my Bachelor Degree course of Automation Engineering.
Presentazione delle attività di ricerca sviluppate nell'ambito del progetto Efficity
Il progetto sta sviluppando una piattaforma software per l’ottimizzazione del progetto, della gestione e del controllo di sistemi e di reti energetiche intelligenti, sia convenzionali sia integrate con fonti rinnovabili, a servizio di distretti urbani ed edifici pubblici/commerciali. L’obiettivo principale è ridurre i consumi energetici, le emissioni di CO2 ed i costi, sfruttando le informazioni rese disponibili dai moderni sistemi di monitoraggio e utilizzando avanzati algoritmi di ottimizzazione ed intelligenza artificiale.
Principali filiere coinvolte: Edilizio, Fornitura di energia elettrica, gas, vapore e servizi energetici, Costruzione di edifici, Ingegneria civile, Lavori di costruzione specializzati, Software, Smart city, Servizi, IT
Sito web del progetto: www.efficity-project.it
Slideshow of my PhD thesis where I show the research activity concerning the integration of gravity data with GOCE gradiometric data leading to a more detailed description of local gravity field and the possibility of small mass anomalies detection.
I cicli in Python 3 - estratto dal corso "Didattica dell'informatica e del Coding Responsabile"
Per il video Sito web https://www.giuseppesportelli.it
per i corsi online
Sito web https://www.corsi-on-line.it/moodle
Simulation and analysis of a linear system in MATLABAlessioSechi
In this article, we delve into the fascinating world of linear systems and their analysis through the powerful tool of MATLAB. A linear system is a fundamental concept in engineering, physics, and mathematics, playing a crucial role in understanding real-world phenomena. By harnessing the capabilities of MATLAB, we will embark on a journey to simulate and thoroughly analyze the behavior of linear systems, shedding light on their characteristics and applications.
Interpolazione in GRASS GIS. Ricavare un modello digitale del terreno a partire da curve di livello e punti quotati. Esercitazione. Lezioni 17-18-19 e 24/01/2012.
Yielding Robot and Rigid Environment - Contact Force Control (IT)EnricoMarinelli3
Italian:
In questa tesi viene proposto un problema di controllo della forza al contatto con l’ambiente per un modello mono-direzionale di un robot manipolatore con una dinamica disaccoppiata.
Cosa sono le self driving cars e la loro tassonomia
Il problema della localizzazione
Modello probablisitico
Filtri di Kalman
Particle filter
Ricerca del percorso
Modello Deep Learning
Conclusioni
onvegno SPEKTRA da A2A - 28 maggio 2024 | COLLA Simone
Robotic Arm Simulation
1. Università degli studi di Salerno
Corso di Laurea Magistrale in Ingegneria Informatica
Anno 2015/2016
Corso di Automazione e Robotica
Presentazione progetto Robotica
Gruppo: Di Gruttola Carmine – Esposito Emiddio
2. Outline
1. Analisi del manipolatore
2. Cinematica diretta del manipolatore
3. Cinematica differenziale, Inversione cinematica e pianificazione
della traiettoria
4. Controllo centralizzato nello spazio giunti
4. Analisi
• Il manipolatore analizzato è lo SmartSix della Comau poggiato su una
base mobile e con un polso sferico all’estremità.
• Il sistema risulta quindi composto da 6 giunti rotoidali disposti su
diversi assi.
• La base mobile è stata modellata aggiungendo due giunti prismatici,
idealmente posti nello stesso punto del primo giunto rotoidale.
5. Utilizzando le convenzioni di
Denavit-Hartenberg, sono state
individuate le terne solidali ai
diversi giunti
6. Dalle terne individuate e dal
datasheet sono stati estratti i
parametri DH che permettono
in maniera agevole di ricavare
le matrici di rotazione
Transizione a 𝜶 d 𝜽
𝑇𝑒𝑟𝑛𝑎 0 → 𝑇𝑒𝑟𝑛𝑎 1 0
𝜋
2
𝑞1
𝜋
2
𝑇𝑒𝑟𝑛𝑎 1 → 𝑇𝑒𝑟𝑛𝑎 2 0
𝜋
2
𝑞2
𝜋
2
𝑇𝑒𝑟𝑛𝑎 2 → 𝑇𝑒𝑟𝑛𝑎 3 0.15 −
𝜋
2
0.45 𝑞3
𝑇𝑒𝑟𝑛𝑎 3 → 𝑇𝑒𝑟𝑛𝑎 4 0.59 0 0 𝑞4
𝑇𝑒𝑟𝑛𝑎 4 → 𝑇𝑒𝑟𝑛𝑎 5 0.13 −
𝜋
2
0 𝑞5
𝑇𝑒𝑟𝑛𝑎 5 → 𝑇𝑒𝑟𝑛𝑎 6 0
𝜋
2
0.64707 𝑞6
𝑇𝑒𝑟𝑛𝑎 6 → 𝑇𝑒𝑟𝑛𝑎 7 0 −
𝜋
2
0 𝑞7
𝑇𝑒𝑟𝑛𝑎 7 → 𝑇𝑒𝑟𝑛𝑎 8 0 0 0.095 𝑞8
7. Cinematica Diretta
• Il primo passo è stato lo sviluppo di una procedura per il calcolo della
cinematica diretta.
• La procedura prende in ingresso la configurazione dei giunti del
manipolatore, una stringa per la tipologia degli angoli di Eulero e le
matrici 𝐴0
𝑏
e 𝐴 𝑒
𝑛
di relazione con la terna mondo e quella end effector
• In uscita restuisce la posizione dell’end effector, l’orientamento
secondo gli angoli scelti, la matrice di rotazione 𝑅 𝑒
𝑏 e un cell array con
tutte le matrici intermedie calcolate.
function [p, phi, R, A] = cindir(q, str, Ab0, Ane)
8. Procedura DHMatrix
• Per aiuto nello sviluppo, è stava sviluppata una procedura che dati i
parametri DH calcola la matrice di rototraslazione corrispondente.
• La stessa poi è stata utilizzata più volte per calcolare 𝐴 𝑒
𝑏, da cui sono
stati ricavate tutte le altre informazioni ritornate da cindir.
function [A] = DHMatrix(a, alpha, d, theta)
9. Verifica
• Confronto dei risultati in uscita dalla procedura realizzata con quelli
simulati dall’ambiente V-REP.
• In primo luogo sono stati verificati i risultati in posizione di
calibrazione, ovvero [0,0,0,−
𝜋
2
,0,0,0,0]T e i valori sono congruenti.
• Un’ulteriore prova è stata fatta in una posizione casuale
[5,5,0,0,−
𝜋
2
,0,0,0]T e si è notata una discrepanza di 0.06 mm nella
coordinata z della posizione causata dai limiti fisici dei giunti, nel caso
particolare dal giunto 5.
• Questo problema è stato risolto utilizzando il file
LimitiManipolatore.m
10. Inversione Cinematica
• Secondo passo è stato il calcolo della cinematica differenziale ai fini
dell’inversione cinematica, implementata attraverso un algoritmo CLIK
del secondo ordine
• La funzione prende in ingresso una configurazione iniziale, una
traiettoria in posizione, velocità e accelerazione, oltre che
informazioni su eventuali ostacoli.
function [q, dq, ddq, e] =
InversioneCinematica(q0, xd, dxd, ddxd, str, Ab0, Ane, obs)
11. Jacobiano Geometrico e Analitico
• Per l’inversione il primo passo è il calcolo dello Jacobiano Geometrico
𝐽 𝑞 e dello Jacobiano Analitico 𝐽 𝐴(𝑞)
• Il primo è stato calcolato a partire dalle formule presenti sul testo e
dalle informazioni ricavate da cindir
• Il secondo è stato calcolato partendo dal primo e utilizzando la
matrice di trasformazione ω = T Φ Φ, per ricavare Φ partendo da
ω.
13. Algoritmo CLIK del 2° ordine
• Utilizzato per compensare l’errore di integrazione in Eulero in avanti.
• Due costanti di retroazione, 𝐾 𝑑 e 𝐾𝑝 scelte uguali per dare un tempo
di assestamento di 50 ms senza oscillazioni, ovvero 𝜔 𝑛 = 100 e 𝜁 = 1
• Proiezione nel nullo per allontanarsi da ostacoli (supposti fermi e
cilindrici) e dai limiti di giunti
𝑞0 = 𝑞0 − 𝑞
𝑞0𝑖 = −𝑘1
𝑞 𝑖−𝑞 𝑚
𝑞 𝑖𝑀− 𝑞 𝑖𝑚
𝑞0𝑖 = 2𝑘2 𝑞𝑖 − 𝑜𝑖
• 𝑘1 e 𝑘2 sono stati fissati a 100 e 10 dopo prove sperimentali
14. Traiettoria - 1
• Traiettoria per operazione di pick and place
• Divisa in due sottotraiettorie:
• Dalla posizione di calibrazione alla posizione di pick
• Dalla posizione di pick alla posizione di place
• Percorso calcolato con ascissa curvilinea con archi di circonferenza
𝛾𝑝 = 𝑐 + 𝑅 ∗
𝑟 ∗ cos(
𝑠
𝑟
)
𝑟 ∗ sin(
𝑠
𝑟
)
0
𝛾𝑓 = 𝑓0 + 𝑠 ∗
𝑓 𝑓−𝑓0
𝐿
• Punto di via calcolato per passare lontano dagli ostacoli
19. Controllo giunti
• L’obiettivo, data una traiettoria nello spazio giunti, è quello di far
inseguire la traiettoria ai giunti.
• Si usa il modello dinamico del manipolatore:
𝐵 𝑞 𝑞 + 𝐶 𝑞, 𝑞 𝑞 + 𝐹 𝑞 + 𝑔 𝑞 = 𝑢
• Sono stati ignorati contributi di attrito statico e forze esterne agenti
sul sistema.
20. Simulazioni
• Ai fini del test, sono state utilizzate due traiettorie.
• Traiettoria costante: si tenta di imporre, per 5 s ad un passo di
campionamento T=0.001 s, 𝑞 =
0.5 0.5 0 −
𝜋
2
0 0.1 1.2 0.9
𝑇
partendo dalla
configurazione di calibrazione 𝑞0 = 0 0 0 −
𝜋
2
0 0 0 0
𝑇
• Traiettoria generata nel secondo homework.
21. Controllo PD + gravità -1
• La strategia di controllo PD + gravità prevede di generare le coppie ai
giunti come composizione di tre contributi:
• Contributo proporzionale alla differenza tra posizione dei giunti desiderata e
posizione reale.
• Contributo proporzionale alla differenza tra velocità dei giunti desiderata e
velocità reale
• Contributo pari al contributo gravitazionale del modello dinamico.
𝑢 = 𝐾𝑝 𝑞 𝑑 − 𝑞 − 𝐾 𝑑 𝑞 + 𝑔(𝑞)
• La strategia converge senza errori per traiettorie costanti.
23. Controllo PD + gravità - 3
• La simulazione è stata effettuata variando i parametri 𝐾𝑝 e 𝐾 𝑑,
impostando entrambe le matrici come matrici diagonali con un valore
fisso sulla diagonale principale e variando questo valore tra 10, 100 e
200, scelti in maniera euristica.
• 𝐾𝑝 = 𝐾 𝑑 =
𝜆 0
0 𝜆
⋯
0 0
0 0
⋮ ⋱ ⋮
0 0
0 0
⋯
𝜆 0
0 𝜆
25. Controllo a dinamica inversa - 1
• La strategia a Dinamica Inversa prevede di compensare la dinamica
del manipolatore in toto.
𝑢 = 𝐵 𝑞 𝑦 + 𝐶 𝑞, 𝑞 𝑞 + 𝐹 𝑞 + 𝑔 𝑞
𝑦 = 𝑞 𝑑 + 𝐾 𝑑 𝑞 𝑑 − 𝑞 + 𝐾𝑝(𝑞 𝑑 − 𝑞)
• Questo permette di ottenere l’equazione dell’errore 𝑒 + 𝐾 𝑑 𝑒 + 𝐾𝑝 𝑒 =
0 avendo posto 𝑒 = 𝑞 𝑑 − 𝑞.
• Questo porta ad un errore che converge a zero, considerando che le
matrici delle costanti di retroazione sono definite positive.
27. Controllo a dinamica inversa - 3
• Costanti di retroazione 𝐾 𝑝 e 𝐾 𝑑 come matrici diagonali basate su i due
parametri che caratterizzano gli autovalori del sistema, 𝜁 e 𝜔 𝑛.
• 𝐾 𝑝 =
𝜔 𝑛
2
0
0 𝜔 𝑛
2 ⋯
0 0
0 0
⋮ ⋱ ⋮
0 0
0 0
⋯
𝜔 𝑛
2
0
0 𝜔 𝑛
2
𝐾 𝑑 =
2𝜁𝜔 𝑛 0
0 2𝜁𝜔 𝑛
⋯
0 0
0 0
⋮ ⋱ ⋮
0 0
0 0
⋯
2𝜁𝜔 𝑛 0
0 2𝜁𝜔 𝑛
• 𝜔 𝑛 è posto pari a 10 e 𝜁 prima pari a 1, per eliminare le oscillazioni, e poi
pari a 0.3, tenendo quindi in conto le oscillazioni nell’errore, per la
traiettoria costante.
• Per la traiettoria non costante si è posto 𝜁 pari a 1.
0.05 s è di un ordine di grandezza almeno maggiore del tempo di campionamento e permette di azzerare l’errore senza rischiare di sconfinare nell’instabilità.
All’inizio partiamo in una posizione errata e comunque l’errore poi tende a zero.
Con i valori 10, 100 e 200 sono state fatte delle prove per osservare di quanto l’errore diminuisce.
10
Wn pari a 10 permette di avere un tempo di assestamento pari a 0.5 secondi perché sono stati tenuti in considerazione dei limiti fisici.
Zita 1
Traiettoria
Ci sono i punti angolosi per la traiettoria e ci danno le variazioni. Gli inviluppi diminuiscono.