Enhancing the useful workspace of a reconfigurable parallel manipulator by grasp point optimization (original) (raw)
Related papers
Task-oriented configuration design for reconfigurable parallel manipulator systems
International Journal of Computer Integrated Manufacturing, 2005
A reconfigurable parallel manipulator system consists of an inventory of standard interchangeable actuator modules, passive joint modules and customizable links and connectors. Owing to the interchangeability and modularity, a parallel manipulator constructed in this manner can have different structures and degrees of freedom (DOF). This article presents a two-stage design methodology, from structure determination to parameter optimization, for determining task-specific optimal configurations of reconfigurable parallel manipulators. In the structure determination stage, a reconfigurable robot assembly database containing the possible parallel manipulator assemblies is established based on enumeration. A TaskToRobot Map is proposed to map the given task description to a suitable manipulator configuration in the database according to the DOFs of the required task. In the parameter optimization stage, design parameters of the selected manipulator structure, such as link lengths, dimensions of the connectors and actuation schemes are identified. As these parameters contain continuous and discrete variables, synthesis of the manipulator parameters is formulated based on a Simplex optimization method. This design methodology is demonstrated effectively in the selection of a reconfigurable parallel manipulator system for a light machining operation.
Design optimization of parallel manipulators with required pose resolution
2011 IEEE International Conference on Robotics and Automation, 2011
The paper proposes an integrated approach to the design optimization of parallel manipulators, which is based on the concept of the workspace grid and utilizes the goal-attainment formulation for the global optimization. To combine the non-homogenous design specification, the developed optimization technique transforms all constraints and objectives into similar performance indices related to the maximum size of the prescribed shape workspace. This transformation is based on the dedicated dynamic programming procedures that satisfy computational requirements of modern CAD. Efficiency of the developed technique is demonstrated via two case studies that deal with optimization of the kinematical and stiffness performances for parallel manipulators of the Orthoglide family.
Workspace-oriented methodology for designing a parallel manipulator
Proceedings of IEEE International Conference on Robotics and Automation, 1996
We present a method for designing optimal parallel manipulators of the Gough platform type, according to design constraints like a specified workspace, best accuracy over the workspace, minimum articular forces for a given load, etc .... A reduced set of design parameters is defined and the workspace constraints are used to compute the zone of the parameters space which define all the robots whose workspace include the desired workspace. Then a numerical search is performed in this zone to determine the robot which optimize some other criterion. We show how the method has been used to design a robot whose accuracy was specified to be better than 1 l m for a nominal load of 500 kg.
2017
Modern robotic manipulators play an essential role in industry, developing several tasks in an easy way, enhancing the accuracy of the final product and reducing the executing time. Also they can be found in other fields as aerospace industry, several medical applications, gaming industry, and so on. In particular, the parallel manipulators have acquired a great relevance in the last years. Indeed, many research activities and projects deal with the study and development of this type of robots. Nevertheless, usually, a bilateral communication between industry and research does not exist, even among the different existing research areas. This causes a lack of knowledge regarding works that have been carried out, the ones that are under development and the possible future investigations. Hence, once a specific field of knowledge has acquired a certain level of maturity, it is convenient to reflect its current state of the art. In this sense, the authors of this paper present a review ...
Workspace Analysis and Optimal Design of 3-PRR Planar Parallel Manipulators
2020
In the optimum design of parallel manipulators, workspace of the manipulator is of greater importance. The shape and area of the workspace are the main parameters under this. In this paper, a new geometrical approach is presented to determine the shape and size of the constant orientation workspace for the 3-PRR planar parallel manipulators. All possibilities of shapes of workspaces are determined with variation of different parameters. For each shape of workspace corresponding geometrical conditions are also put forth. Closed from area expression of workspace is derived by geometrical approach for each shape. Such closed form expression of area is not possible with non-dimensional approach. This becomes extremely useful during optimal design procedure. A look-up table is also presented seeing which the designer can choose geometrical conditions between different parameters which will ensure a void free workspace. A case study is presented wherein a user gives his required workspace...
CAD-enhanced workspace optimization for parallel manipulators: A case study
2010 IEEE International Conference on Automation Science and Engineering, 2010
The challenges of workspace determination of parallel manipulators (PMs) arise principally from the lack of analytical solutions of the forward kinematics. The inverseposition kinematics based approach for determining workspace tends to be inefficient, time consuming and unsophisticated. In this paper, we present a geometry-based method for accurate and computationally effective calculation of the workspace of a constrained parallel manipulator. We illustrate how boolean geometric operations can simplify the process of finding the workspace and optimizing the designs. Comparative performance studies, in terms of accuracy and computational performance, are performed to benchmark the approach against more conventional methods. Finally, we examine ways to further automate the process using a CAD package.
Workspace and Singularity Analysis for a Reconfigurable Parallel Robot
In this paper several aspects regarding the workspace analysis and singularity identification of a reconfigurable parallel robot are presented. Using the developed kinematic model, the reconfigurable parallel robot singularities within the generated workspace are identified. The simulation results for the workspace and singularities generation are also presented.
Machines, 2021
Parallel robots with configurable platforms are a class of robots in which the end-effector has an inner mobility, so that its overall shape can be reconfigured: in most cases, the end-effector is thus a closed-loop kinematic chain composed of rigid links. These robots have a greater flexibility in their motion and control with respect to rigid-platform parallel architectures, but their kinematics is more challenging to analyze. In our work, we consider n-RRR planar configurable robots, in which the end-effector is a chain composed of n links and revolute joints, and is controlled by n rotary actuators located on the base of the mechanism. In particular, we study the geometrical design of such robots and their direct and inverse kinematics for n=4, n=5 and n=6; we employ the bilateration method, which can simplify the kinematic analysis and allows us to generalize the approach and the results obtained for the 3-RRR mechanism to n-RRR robots (with n>3). Then, we study the singularity configurations of these robot architectures. Finally, we present the results from experimental tests that have been performed on a 5–RRR robot prototype.
Designing a Parallel Manipulator for a Specific Workspace
The International Journal of Robotics Research, 1997
We present an algorithm to determine all the possible ge ometries of Gough-type 6-DOF parallel manipulators whose workspace must include a desired workspace. This desired workspace is a set of geometric objects, limited here to points and segments, which describes the desired locations of the cen ter of the moving platform. It is assumed that the orientation of the platform is fixed for each given object. This algorithm takes into account the leg-length limits, the mechanical limits on the passive joints, and interference between links.
Workspace Analysis of a New Parallel Manipulator
1999
This paper studies the workspace of a six-DC)F parallel manipulator of three-PPSR (prismatic-prismaticspheric-revolute) type. It is well recognized that the most significant drawback of parallel manipulators is their limited workspace. To develop new parallel mechanisms with a larger workspace is of interest to additional applications. The mechanism of the three-PPSR manipulator and its variations are briefly analyzed first. The workspace is then determined and the effects of joint limit and limb interference constraints on the workspace shape and size are studied. The constituent regions of the workspace corresponding to different classes of manipulator poses are discussed. It is shown that the workspace of this parallel manipulator is larger than that of a comparable Stewart platform especially in the vertical direction.