WORKSPACE ANALYSIS AND OPTIMIZATION OF THE PARALLEL ROBOTS BASED ON COMPUTER-AIDED DESIGN APPROACH

This paper provides workspace determination and analysis based on the graphical technique of both spatial and planar parallel manipulators. The computation and analysis of workspaces will be carried out using the parameterization and three-dimensional representation of the workspace. This technique is implemented in CAD (Computer Aided Design) Software CATIA workbenches. In order to determine the workspace of the proposed manipulators, the reachable region by each kinematic chain is created as a volume/area; afterwards, the full reachable workspace is obtained by the application of a Boolean intersection function on the previously generated volumes/areas. Finally, the relations between the total workspace and the design parameters are simulated, and the Product Engineering Optimizer workbench is used to optimize the design variables in order to obtain a maximized workspace volume. Simulated annealing (SA) and Conjugate Gradient (CG) are considered in this study as optimization tools

Evaluation of automated decisionmaking methodologies and development of an integrated robotic system simulation. Appendix A: ROBSIM user's guide

The purpose of the Robotics Simulation Program is to provide a broad range of computer capabilities to assist in the design, verification, simulation, and study of robotics systems. ROBSIM is program in FORTRAN 77 for use on a VAX 11/750 computer under the VMS operating system. This user's guide describes the capabilities of the ROBSIM programs, including the system definition function, the analysis tools function and the postprocessor function. The options a user may encounter with each of these executables are explained in detail and the different program prompts appearing to the user are included. Some useful suggestions concerning the appropriate answers to be given by the user are provided. An example user interactive run in enclosed for each of the main program services, and some of the capabilities are illustrated

Method and apparatus for configuration control of redundant robots

A method and apparatus to control a robot or manipulator configuration over the entire motion based on augmentation of the manipulator forward kinematics is disclosed. A set of kinematic functions is defined in Cartesian or joint space to reflect the desirable configuration that will be achieved in addition to the specified end-effector motion. The user-defined kinematic functions and the end-effector Cartesian coordinates are combined to form a set of task-related configuration variables as generalized coordinates for the manipulator. A task-based adaptive scheme is then utilized to directly control the configuration variables so as to achieve tracking of some desired reference trajectories throughout the robot motion. This accomplishes the basic task of desired end-effector motion, while utilizing the redundancy to achieve any additional task through the desired time variation of the kinematic functions. The present invention can also be used for optimization of any kinematic objective function, or for satisfaction of a set of kinematic inequality constraints, as in an obstacle avoidance problem. In contrast to pseudoinverse-based methods, the configuration control scheme ensures cyclic motion of the manipulator, which is an essential requirement for repetitive operations. The control law is simple and computationally very fast, and does not require either the complex manipulator dynamic model or the complicated inverse kinematic transformation. The configuration control scheme can alternatively be implemented in joint space

Design of parallel micromechanisms for knotting operation

Thesis (Master)--Izmir Institute of Technology, Mechanical Engineering, Izmir, 2009Includes bibliographical references (leaves: 61-63)Text in English; Abstract: Turkish and Englishix, 63 leavesThis thesis covers a study on the design of micromechanisms which are capable of imitating the knotting operation and their applications on carpet manufacturing.For this purpose, motion generation synthesis of a planar two degree-of-freedom serial manipulator is performed for a given path by using interpolation approximation. For a given four points, four design parameters are solved as a result of non-linear equations. Also, analysis of each stages of knotting operation is kinematically performed for the design of a cam-actuated mechanism which is designed as an alternative concept. Results of these analysis are used for the design of cam profiles those of which actuates the manipulators.After design stage of knotting micromechanisms, fully automated carpet loom design is introduced for a real-life experiment of designed mechanisms. Finally, assembly considerations of carpet loom and knotting mechanisms are given for carpet manufacturing purpose

Dynamic Control of Mobile Multirobot Systems: The Cluster Space Formulation

The formation control technique called cluster space control promotes simplified specification and monitoring of the motion of mobile multirobot systems of limited size. Previous paper has established the conceptual foundation of this approach and has experimentally verified and validated its use for various systems implementing kinematic controllers. In this paper, we briefly review the definition of the cluster space framework and introduce a new cluster space dynamic model. This model represents the dynamics of the formation as a whole as a function of the dynamics of the member robots. Given this model, generalized cluster space forces can be applied to the formation, and a Jacobian transpose controller can be implemented to transform cluster space compensation forces into robot-level forces to be applied to the robots in the formation. Then, a nonlinear model-based partition controller is proposed. This controller cancels out the formation dynamics and effectively decouples the cluster space variables. Computer simulations and experimental results using three autonomous surface vessels and four land rovers show the effectiveness of the approach. Finally, sensitivity to errors in the estimation of cluster model parameters is analyzed.Fil: Mas, Ignacio Agustin. Instituto Tecnológico de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Kitts, Christopher. Santa Clara University; Estados Unido

Path generation analysis of flexible manipulators

Thesis (Master)--Izmir Institute of Technology, Mechanical Engineering, Izmir, 2008Includes bibliographical references (leaves: 33)Text in English; Abstract: Turkish and Englishviii, 33 leavesBy the improving technology, usage of robotic manipulators has been increased a lot in last decades. Robotic manipulators are usually used in continuous production and dangerous operations. General industries, medical applications and space missions are the most important usage areas for these manipulators. In these applications, the manipulator faces to deviation of the end effecter which depends on many reasons like friction, vibration, elastic and plastic deformations. However, the robotic calculations made, as the links of the manipulator are rigid and other effects are neglected.The aim of this thesis is to improve a path generation analysis method for the three link flexible planer manipulator. The three link manipulator is considered to investigate the flexibility effect of links on path generation. Firstly the problem and solution method is introduced then the inverse kinematic analysis is applied for the three link rigid planer manipulator. The finite element model of the three link flexible planer manipulator is developed by using the plane frame element. The general equations of the tip point displacements of the three link flexible planer manipulator are expressed and Matlab program is coded. Finally, the library robots made by aluminum and steel are chosen for numerical examples. In conclusion the results of numerical example are shown for each position of the manipulator and discussed

Synthesis of Planar Parallel Mechanism

Parallel mechanisms are found as positioning platforms in several applications in robotics and production engineering. Today there are various types of these mechanisms based on the strcture, type of joints and degree of freedom. An important and basic planar mechanism providing three degree of freedom at the end-effector (movable platform) is a 3-RPR linkage. Here the underscore below P indicates the presence of actuated prismatic joints and 3 indicates the number of legs used to carry the mobile platform. A lot of work has been done on this mechanism since 1988. In the present work, the kinematics of 3-RPR linkage is specifically studied to understand the synthesis procedure. The forward kinematics in parallel mechanisms is a multi-solution problem and involves cumbersome calculations compared to inverse kinematics. In inverse kinematics, we design the actuator input kinematic parameters for a known table center coordinates. In other words it is a transformation of platform pose vector to the actuator degrees of freedom. In 3-RPR mechanism considered in present task, the actuators are sliders and hence the slider displacements reflect the input degrees of freedom. On the other hand, for a known posture (available slider displacement status), the table center coordinates are predicted in forward kinematics. In present work, forward kinematics solutions are obtained by defining error function and optimizing it using genetic algorithms programs. Also, the workspace and Jacobian matrices are computed at corresponding solution and singularity analysis is briefly highlighted

Robust tracking control of two-degrees-of-freedom mobile robots

A robust tracking controller for a mobile robot with two degrees of freedom has been developed. It is implemented and tested on a real mobile robot. Where other controllers show decreasing performance for low reference velocities, the performance of this controller depends only on the geometry of the reference trajectory. This allows accurate positioning at low speeds, close to obstacles. The dynamics of the velocity-controlled mobile robot are considered as perturbed unity transfer from input velocity to actual velocity. It is shown that the tracking controller is robust with respect to these perturbations

Developing Intuitive, Closed-Loop, Teleoperative Control of Continuum Robotic Systems

This thesis presents a series of related new results in the area of continuum robot teleoperation and control. A new nonlinear control strategy for the teleoperation of extensible continuum robots is described. Previous attempts at controlling continuum robots have proven difficult due to the complexity of their system dynamics. Taking advantage of a previously developed dynamic model for a three-section, planar, continuum manipulator, we present an adaptation control-inspired law. Simulation and experimental results of a teleoperation scheme between a master device and an extensible continuum slave manipulator using the new controller are presented. Two novel user interface approaches to the teleoperation of continuum robots are also presented. In the first, mappings from a six Degree-of-Freedom (DoF) rigid-link robotic arm to a nine degree-of-freedom continuum robot are synthesized, analyzed, and implemented, focusing on their potential for creating an intuitive operational interface. Tests were conducted across a range of planar and spatial tasks, using fifteen participant operators. The results demonstrate the feasibility of the approach, and suggest that it can be effective independent of the prior robotics, gaming, or teleoperative experience of the operator. In the second teleoperation approach, a novel nine degree-of-freedom input device for the teleoperation of extensible continuum robots is introduced. As opposed to previous works limited by kinematically dissimilar master devices or restricted degrees-of-freedom, the device is capable of achieving configurations identical to a three section continuum robot, and simplifying the control of such manipulators. The thesis discusses the design of the control device and its construction. The implementation of the new master device is discussed and the effectiveness of the system is reported

\u3cem\u3eGRASP News\u3c/em\u3e, Volume 6, Number 1

A report of the General Robotics and Active Sensory Perception (GRASP) Laboratory, edited by Gregory Long and Alok Gupta