Teaching robot modelling and control with RobLib

The paper presents a program for robotics education that runs on standard PC's under the Microsoft Windows environment. The RobLib package is designed for undergraduate students and emphasis the fundamental aspects of robot modelling and control. The software is self-explanatory and uses menus, dialog boxes with figures and context-dependent on-line help. In this perpective, students are motivated to investigate on the workspace, kinematics, dynamics, trajectory planning, position and force control of manipulators. Based on this first experience, further studies on robotics, using more sophisticated packages and concepts, are, then, more attractive from the students point of view.N/

Winrob: An educational program for robotics

The paper presents a program for robotics education that runs on standard IBM-PCs under the Microsoft Windows enviroment. The WinRob package is designed for undergraduate students and emphasises the fundamental aspects of robot modelling and control. The software is self-explanatory and uses menus, dialog boxes and context-dependent on-line help.info:eu-repo/semantics/publishedVersio

Force control and nonlinear master-slave force profile to manage an admittance type multi-fingered haptic user interface

Natural movements and force feedback are important elements in using teleoperated equipment if complex and speedy manipulation tasks are to be accomplished in remote and/or hazardous environments, such as hot cells, glove boxes, decommissioning, explosives disarmament, and space to name a few. In order to achieve this end the research presented in this paper has developed an admittance type exoskeleton like multi-fingered haptic hand user interface that secures the user’s palm and provides 3-dimensional force feedback to the user’s fingertips. Atypical to conventional haptic hand user interfaces that limit themselves to integrating the human hand’s characteristics just into the system’s mechanical design this system also perpetuates that inspiration into the designed user interface’s controller. This is achieved by manifesting the property differences of manipulation and grasping activities as they pertain to the human hand into a nonlinear master-slave force relationship. The results presented in this paper show that the admittance-type system has sufficient bandwidth that it appears nearly transparent to the user when the user is in free motion and when the system is subjected to a manipulation task, increased performance is achieved using the nonlinear force relationship compared to the traditional linear scaling techniques implemented in the vast majority of systems

Kinematic Modelling and Simulation of 3-Axis Robotic Arm for Performing Welding Operations with Arbitarary Weld Joint Profiles

Robot welding is a fast and accurate welding to obtain a good joint strength. In this thesis, a 3-axis robotic arm has been modeled using CAD tool for performing welding operations. For the developed robotic arm, forward & inverse kinematic analyses have been performed to move the weld torch in the desired trajectory. A new seam tracking methodology, named sewing technique has been introduced for the welded joints available in Computer Aided Design (CAD) environment. This methodology, gives the seam path by drawing a line through the adjacent centroids of curve fitted in the weld joint volume. Obtained geometric path and kinematic constraints are given as input to the modeled robot for performing welding operation followed by desired trajectory. Validation of the developed methodology has been done through simulation results while performing welding operations for different weld profiles

Fast heuristic methods of numerical solution of inverse kinematics

Při zkoumání rozsáhlých robotických soustav pro potřeby firmy ŠKODA AUTO a.s. bylvytvořen software, který je zaměřen na kontrolu robotů a robotových standardů používanýchv koncernu Volkswagen AG. Součástí je i matematická knihovna, která řeší několik základníinženýrských úloh. Jedná se o přímou a inverzní kinematickou úlohu v robotice a o řešení soustavlineárních rovnic více proměnných. Při zkoumání numerických metod v rámci programováníuvedených úloh byly vyvinuty dva zcela nové algoritmy. Jedná se o metodu relaxace úhlu, která jeurčena pro řešení soustav lineárních rovnic. Může být také nepřímo použita pro řešení inverzníkinematické úlohy v robotice. Druhý algoritmus je přímo určen pro řešení inverzní kinematické úlohyv robotice. V tomto případě se jedná o metodu relaxace délky.Metoda relaxace úhlu je diskutována z hlediska základního principu a numerických vlastnostípři výpočtu soustav lineárních rovnic. Je zkoumána rychlost konvergence, závislost na číslupodmíněnosti a schopnost řešit obecné soustavy lineárních rovnic pro různé podoby matice soustavy.V rámci jednotlivých experimentů se metoda porovnává s výsledky známých numerických metod.Ukazuje se, že metoda relaxace úhlu konverguje k výsledkům podobným jako Mooreova-Penroseovapseudoinverze i v případě singulární matice soustavy. Tato vlastnost je vhodná pro řešení inverzníkinematické úlohy v robotice, protože se při výpočtu matice soustavy dynamicky mění v závislosti napostavení kinematické struktury robota.Aby bylo možné metodu relaxace úhlu použít pro výpočet inverzní kinematické úlohyv robotice, vychází práce z přístupů, které převádí tuto problematiku do podoby soustav lineárníchrovnic. Jelikož inverzní kinematická úloha v robotice vede na soustavy nelineárních rovnic, jedná seo přístupy, které linearizují řešení ve vybraném pracovním bodě pomocí Jacobiho matice, tzn.Newtonova metoda, inverze Jacobiho matice a metoda Levenberg-Marquardt. Všechny tři přístupy jsouodzkoušeny na kinematické struktuře planárního manipulátoru a robotu KUKA KR210 R2700 EXTRA.Vzniklé soustavy lineárních rovnic jsou řešeny standardní cestou pomocí Mooreovy-Penroseovypseudoinverze a zároveň metodou relaxace úhlu. Výsledky obou přístupů jsou vyhodnocenya porovnány.Na závěr práce je diskutována metoda relaxace délky, kterou lze zařadit do skupinyheuristických metod. Metoda je popsána z hlediska jejího principu a porovnána se známýmiheuristickými metodami CCD a FABRIK.As part of a research of large robotic systems for the needs of SKODA AUTO, a.s. companya inspectional software was developed. The software focuses on a control of robots and programmingstandards used by Volkswagen AG. The software includes a mathematical library which solves severalbasic engineering tasks. It is a problem of forward and inverse kinematics in robotics and a solution ofsystems of linear equations. This work introduces two completely new algorithms which weredeveloped during the programming of the mathematical library. It is angle relaxation method which isdesigned for solving of systems of linear equations. It can also be used indirectly to solve inversekinematics in robotics. The second algorithm is designed directly for solving of inverse kinematics inrobotics. In this case the work talks about length relaxation method.The angle relaxation method is discussed from the point of view of basic principle andnumerical properties. A speed of convergence, a dependence on the condition number and an ability tosolve general systems of linear equations for different forms of matrices were examined. Results ofangle relaxation method were compared with results of known numerical methods. It appears that theangle relaxation method converges to results similar to results of Moore-Penrose pseudoinverse. Thisproperty is suitable for the solving of inverse kinematics in robotics because the system matrix isdynamically changed during a calculation depending on a position of the kinematic structure of therobot.In order to use the angle relaxation method to calculate the inverse kinematics in robotics, thework is based on approaches which transform the problem into systems of linear equations. The inversekinematics in robotics leads primarily to systems of nonlinear equations. For this reason approacheswere chosen which linearize the equation using a Jacobian matrix, i.e. Newton's method, inverseJacobian method and Levenberg-Marquardt method. All three approaches were tested on the kinematicstructure of the planar manipulator and the robot KUKA KR210 R2700 EXTRA. Systems of linearequations were solved by a standard way using Moore-Penrose pseudoinverse and at the same time bythe angle relaxation method. Results of both approaches were evaluated and compared.At the end of this work the length relaxation method is discussed which can be included in thegroup of heuristic methods. The length relaxation method is described from the point of view of basicprinciple and compared with known heuristic methods CCD and FABRIK

Design and Development of an Automated Mobile Manipulator for Industrial Applications

This thesis presents the modeling, control and coordination of an automated mobile manipulator. A mobile manipulator in this investigation consists of a robotic manipulator and a mobile platform resulting in a hybrid mechanism that includes a mobile platform for locomotion and a manipulator arm for manipulation. The structural complexity of a mobile manipulator is the main challenging issue because it includes several problems like adapting a manipulator and a redundancy mobile platform at non-holonomic constraints. The objective of the thesis is to fabricate an automated mobile manipulator and develop control algorithms that effectively coordinate the arm manipulation and mobility of mobile platform. The research work starts with deriving the motion equations of mobile manipulators. The derivation introduced here makes use of motion equations of robot manipulators and mobile platforms separately, and then integrated them as one entity. The kinematic analysis is performed in two ways namely forward & inverse kinematics. The motion analysis is performed for various WMPs such as, Omnidirectional WMP, Differential three WMP, Three wheeled omni-steer WMP, Tricycle WMP and Two steer WMP. From the obtained motion analysis results, Differential three WMP is chosen as the mobile platform for the developed mobile manipulator. Later motion analysis is carried out for 4-axis articulated arm. Danvit-Hartenberg representation is implemented to perform forward kinematic analysis. Because of this representation, one can easily understand the kinematic equation for a robotic arm. From the obtained arm equation, Inverse kinematic model for the 4-axis robotic manipulator is developed. Motion planning of an intelligent mobile robot is one of the most vital issues in the field of robotics, which includes the generation of optimal collision free trajectories within its work space and finally reaches its target position. For solving this problem, two evolutionary algorithms namely Particle Swarm Optimization (PSO) and Artificial Immune System (AIS) are introduced to move the mobile platform in intelligent manner. The developed algorithms are effective in avoiding obstacles, trap situations and generating optimal paths within its unknown environments. Once the robot reaches its goal (within the work space of the manipulator), the manipulator will generate its trajectories according to task assigned by the user. Simulation analyses are performed using MATLAB-2010 in order to validate the feasibility of the developed methodologies in various unknown environments. Additionally, experiments are carried out on an automated mobile manipulator. ATmega16 Microcontrollers are used to enable the entire robot system movement in desired trajectories by means of robot interface application program. The control program is developed in robot software (Keil) to control the mobile manipulator servomotors via a serial connection through a personal computer. To support the proposed control algorithms both simulation and experimental results are presented. Moreover, validation of the developed methodologies has been made with the ER-400 mobile platform