fundamentals of mechanics of robotic manipulation

This book has evolved from a course on Mechanics of Robots that the author has thought for over a dozen years at the University of Cassino at Cassino, Italy. It is addressed mainly to graduate students in mechanical engineering although the course has also attracted students in electrical engineering. The purpose of the book consists of presenting robots and robotized systems in such a way that they can be used and designed for industrial and innovative non-industrial applications with no great efforts. The content of the book has been kept at a fairly practical level with the aim to teach how to model, simulate, and operate robotic mechanical systems. The chapters have been written and organized in a way that they can be red even separately, so that they can be used separately for different courses and readers. However, many advanced concepts are briefly explained and their use is empathized with illustrative examples. Therefore, the book is directed not only to students but also to robot users both from practical and theoretical viewpoints. In fact, topics that are treated in the book have been selected as of current interest in the field of Robotics. Some of the material presented is based upon the author’s own research in the field since the late 1980’s. In Chapter 1 an introductory overview of robots and Robotics is given by presenting basic characteristics and motivation for robot uses and by outlining a historical development. Chapter 1 outlines briefly the history and development that led to robots and robotized systems. The arguments are presented as a motivation for the interest on the applications of robots as well as for an in-depth study of the theoretical aspects. The technical evolution of automatic systems to robots is outlined by finally presenting the technical characteristics of a robot as a special automatic component. Indeed robots can be considered the most advanced automatic systems. With the aim to justify extensive use of robots an economic evaluation of using robots is presented and discussed. In addition, many other problems and aspects are outlined with the aim to give a wide view of the concerns related to the use of the robots not only in an industrial plant, but also in the human society. Thus, arguments from economy, psychology, and sociology are listed to give an account of all the problems that should be considered when using robots. However, the book concerns with technical aspects that are still addressing great attention even from research viewpoint. Thus, at the end of the chapter there is a list of forum where the technical aspects of Robotics are usually discussed. This information can be considered important even for further study of readers on the topics of this book and related arguments. Chapter 2 deals with analysis and synthesis of manipulation by using men, automatic systems, or robots. The problem is attached in a way that any of the above-mentioned systems can apply the results of the study of a manipulation to give a rational flexible plan for a manipulative task. In particular, the aim of a flexible programming and design of a manipulation sequence is achieved by decomposing a manipulation into operations, phases, and elementary actions that have a decreasing content of manipulative actions. A general procedure is outlined for analyzing manipulations as based on the above-mentioned decomposition. The procedure is formulated with no specific reference to robots, although the rest of the chapter describes its application with robots. Thus, the programming issue is discussed by referring to industrial robots and particularly to VAL-II language, which is used to describe peculiarities of grammar and syntax of a robot language. Several examples are illustrated and discussed by using teaching experiences and practical applications of industrial robots. The aim of describing many examples consists of presenting how a theoretical study of manipulation can be of great help for practical applications, even for a flexible programming of robotized solutions. Chapter 3 is devoted to explain the behavior and operation of robots from Mechanics viewpoint with the aim to deduce formulations that are useful for analysis and design purposes. The arguments are attached in the frame of Mechanics of Robots, but the treatment is synthetic with the aim to deduce useful formulation even for simulation purpose on PC. Kinematics is approached by defining a model through HD (Hartenberg -Denavit) parameters. The position analysis is formulated by using Transformation Matrix (in homogenous coordinates), which is described from several viewpoints. The joint space and actuator spaces are illustrated and a simple example shows numerical details. A specific attention is addressed to workspace analysis, which is formulated in several algorithms. The position analysis is inverted to define the manipulator design problem. General formulations are outlined by using techniques deduced from the synthesis of mechanisms, but also an optimization problem is formulated and discussed. The path planning is approached starting from formulation of Inverse Kinematics. The two subjects are described as strongly related to each other, although some specific formulations are deduced for each of them. The singularity problem is illustrated by using the Jacobian analysis. The Jacobian matrix of a manipulator is defined and algorithms are outlined for its evaluation. Addressing to velocity and acceleration analysis with recursive algorithms completes the Kinematics, which makes use of the Transformation Matrix. The static behavior of a manipulator is studied through a suitable model, which is described with specific attention and comments. Then, the static equilibrium is formulated by using the traditional approach with D’Alembert Principle. An example is included to show closed-form expressions as well as to discuss numerical issues. The static model is further completed with inertia characteristics in order to study the Dynamics of a manipulator. The two fundamental approaches of Newton-Euler Equations and Lagrange Formulation are treated to give the equations of motion and constraints forces. Examples are used to illustrate and discuss details of the algorithms and numerical problems of simulation. Specific sections are devoted to discuss other main characteristics of a manipulator: repeatability, precision, and stiffness. Formulation and comments are deduced with the aim to help the understanding of their effect on the efficiency of a robot. The end of the chapter is devoted to introduce the Mechanics of parallel manipulators, mainly referring to a prototype CaPaMan (Cassino Parallel Manipulator) that has been designed and built at Laboratory of Robotics and Mechatronics in Cassino. Synthetically the fundamentals of the Mechanics of parallel manipulators is outlined similarly to the previous sections for serial manipulators with the aim to show differences but analogies in the formulation and behavior. Chapter 4 deals with problems of grasping as an important aspect for a manipulator component and manipulative task. Gripping devices are reviewed together with their fundamental characteristics in order to give a view of existent variety. However, the attention is focused on two-finger grippers, which are justified and motivated by considering the model of grasp and relevant Statistics for two-finger grasp applications. Thus, the two-finger grasp is studied in depth by means of models and formulations, which are also useful for design algorithms and force control purposes. The design issue is treated by looking at the mechanisms that are used in grippers and formulating the design problem, even as an optimization problem when suitable performance indices are defined. The grasp force control is described by referring to the Mechatronics operation and design of a gripper. In particular, different control schemes are described by using electropneumatic systems, since they are the most used in industrial applications. Some laboratory experiences are described and discussed as example of designing, operating, practicing with a gripping system. The Index consists of an alphabetically ordered list of subjects treated in the book with the indication of the corresponding pages. Bibliography consists of a list of main books in the field of Robotics, and specifically on Mechanics of Robots with the aim to give further sources of reading and references of different approaches. In the book there is not any reference to Bibliography. Bibliography has been limited to few significant books, although the literature on Robotics and mechanical aspects of Robots is very rich. However, main sources have been indicated in Chapter 1 as publications in Journals and Conference Proceedings in which readers can also find new material.