Robotic Manipulator Calibration

Describes the details of the calibration process step-by-step, covering systems modeling, measurement, identification, correction and performance evaluation. Calibration techniques are presented with an explanation of how they interact with each other as they are modified. Shows the reader how to determine if, in fact, a robot problem is a calibration problem and then how to analyze it.

Calibration is playing an increasingly important role in industrial robotics. Higher accuracy demands are being placed on flexible assembly and manufacturing systems which in turn require robot manufacturers to produce higher quality precision robots.

Robot calibration is the process of enhancing the accuracy of a robot by modifying its control software. This book provides a comprehensive treatment of the theory and implementation of robot calibration using computer vision technology. It is the only book to cover the entire process of vision-based robot calibration, including kinematic modeling, camera calibration, pose measurement, error parameter identification, and compensation. The book starts with an overview of available techniques for robot calibration, with an emphasis on vision-based techniques. It then describes various robot-camera systems. Since cameras are used as major measuring devices, camera calibration techniques are reviewed. Camera-Aided Robot Calibration studies the properties of kinematic modeling techniques that are suitable for robot calibration. It summarizes the well-known Denavit-Hartenberg (D-H) modeling convention and indicates the drawbacks of the D-H model for robot calibration. The book develops the Complete and Parametrically Continuous (CPC) model and the modified CPC model, that overcome the D-H model singularities. The error models based on these robot kinematic modeling conventions are presented. No other book available addresses the important, practical issue of hand/eye calibration. This book summarizes current research developments and demonstrates the pros and cons of various approaches in this area. The book discusses in detail the final stage of robot calibration - accuracy compensation - using the identified kinematic error parameters. It offers accuracy compensation algorithms, including the intuitive task-point redefinition and inverse-Jacobian algorithms and more advanced algorithms based on optimal control theory, which are particularly attractive for highly redundant manipulators. Camera-Aided Robot Calibration defines performance indices that are designed for off-line, optimal selection of measurement configurations. It then describes three approaches: closed-form, gradient-based, and statistical optimization. The included case study presents experimental results that were obtained by calibrating common industrial robots. Different stages of operation are detailed, illustrating the applicability of the suggested techniques for robot calibration. Appendices provide readers with preliminary materials for easier comprehension of the subject matter. Camera-Aided Robot Calibration is a must-have reference for researchers and practicing engineers-the only one with all the information!

This book mainly shows readers how to calibrate and control robots. In this regard, it proposes three control schemes: an error-summation enhanced Newton algorithm for model predictive control; RNN for solving perturbed time-varying underdetermined linear systems; and a new joint-drift-free scheme aided with projected ZNN, which can effectively improve robot control accuracy. Moreover, the book develops four advanced algorithms for robot calibration – Levenberg-Marquarelt with diversified regularizations; improved covariance matrix adaptive evolution strategy; quadratic interpolated beetle antennae search algorithm; and a novel variable step-size Levenberg-Marquardt algorithm – which can effectively enhance robot positioning accuracy. In addition, it is exceedingly difficult for experts in other fields to conduct robot arm calibration studies without calibration data. Thus, this book provides a publicly available dataset to assist researchers from other fields in conducting calibration experiments and validating their ideas. The book also discusses six regularization schemes based on its robot error models, i.e., L1, L2, dropout, elastic, log, and swish. Robots’ positioning accuracy is significantly improved after calibration. Using the control and calibration methods developed here, readers will be ready to conduct their own research and experiments.

Robot manipulators are developing more in the direction of industrial robots than of human workers. Recently, the applications of robot manipulators are spreading their focus, for example Da Vinci as a medical robot, ASIMO as a humanoid robot and so on. There are many research topics within the field of robot manipulators, e.g. motion planning, cooperation with a human, and fusion with external sensors like vision, haptic and force, etc. Moreover, these include both technical problems in the industry and theoretical problems in the academic fields. This book is a collection of papers presenting the latest research issues from around the world.

A general method for establishing a kinematic model of a robotic manipulator with either a full or partial pose calibration system is developed. The theory applicable to modeling of mechanisms is introduced, as is robotic manipulator calibration. Given a general over-specified kinematic model, a method is developed, with the associated algorithms for a six degree of freedom manipulator, that identifies non-unique parameter sets for any given partial pose measurement system. This method is applied and demonstrated on three existing calibration methods.

Muitos dos robôs industriais utilizados atualmente seguem uma programaçãobaseada em rastreamento de trajetórias. O robô é guiado por um operador humano paralocalizações fixas onde ele atuará. Esses movimentos são, então, gravados na linguagemde programação residente no controlador do robô, de forma que este seja capaz derepetir as tarefas. Este método pode ser suficiente para, por exemplo, movimentarobjetos entre locais fixos. Como o robô está treinado para se movimentar em posiçõesfixas, todas as partes do manipulador, bem como todos os objetos que serãomanipulados devem estar em posições bem definidas, ou uma nova programação deveráser feita. Outra metodologia é a de teleoperação, na qual a movimentação de sistemasrobóticos é executada em modo manual, no qual o operador trabalha em uma arquiteturamestre-escravo controlando direta e continuamente as posições do manipulador. Paraessas tarefas é necessário apenas que o sistema possua um alto grau de repetibilidade, uma vez que quaisquer erros absolutos de posicionamento são visualmentecompensados pelo operador humano. Porém em certas aplicações robóticas essastécnicas de programação de manipuladores são impraticáveis ou insatisfatórias. Aprimeira vem a ser impraticável no caso de alta variabilidade do ambiente onde a tarefaestá sendo feita. O segundo método atribui ao robô uma precisão absoluta baixa, devidoa própria deficiência da percepção humana. Este trabalho segue pelas tendênciasmodernas de automação, as quais vêm colocando uma crescente ênfase em robôsguiados por sensores e programação off-line, automatizando total ou parcialmentemuitas das tarefas a serem executadas. Sensores, como câmeras ligadas a um sistema devisão computacional, detectam diferenças entre a posição real do manipulador e aposição desejada. Estas diferenças são então enviadas para os controladores, para queestes corrijam a trajetória pré-programada. Os comandos de movimento do manipuladorsão programados off-line por um sistema de CAD, sem a necessidade de ativar o robô, permitindo maior velocidade em sua validação e na resolução de problemas. Apresentam-se neste trabalho metodologias e técnicas para o posicionamento domanipulador utilizando-se, para tanto, câmeras em sua extremidade. Uma vezposicionado o manipulador em relação ao espaço de coordenadas do mundo, é possíveldeslocá-lo com segurança e precisão em sua área de trabalho, o que é imprescindívelpara automatização de tarefas complexas. O trabalho está concentrado nas aplicações detécnicas de visão computacional à calibração de manipuladores. Como estudo de casoutiliza-se uma situação real, de um manipulador submarino de seis graus de liberdade, para intervenções submarinas em plataformas de petróleo. Abordam-se a calibração decâmeras, reconhecimento de padrões, correlação de padrões em imagens distintas, estereoscopia, cinemática direta e inversa de manipuladores e a união de todas estastécnicas para o posicionamento do manipulador em sua área de trabalho.

Incorporating papers from the 12th International Symposium on Experimental Robotics (ISER), December 2010, this book examines the latest advances across the various fields of robotics. Offers insights on both theoretical concepts and experimental results.

A general method for establishing a kinematic model of a robotic manipulator with either a full or partial pose calibration system is developed. The theory applicable to modeling of mechanisms is introduced, as is robotic manipulator calibration. Given a general over-specified kinematic model, a method is developed, with the associated algorithms for a six degree of freedom manipulator, that identifies non-unique parameter sets for any given partial pose measurement system. This method is applied and demonstrated on three existing calibration methods.