Determination of 6D Workspaces of Gough-Type Parallel Manipulator and Comparison between Different Geometries (original) (raw)

An overview of the kinematics and workspace of robots with different structures

Acta Mechatronica

Robotics is gaining an important place in many areas of industrial production nowadays. With the growing number of robots in production, we are coming to the solution of various tasks to ensure their optimal activity when handling objects or during other technological activities. These are tasks such as planning its movement, planning the robot's trajectory, navigation and tracking the movement of the end member. In this article, we will deal with the issue of robot workspace structures and determining the robot workspace of a specific robot model.

Workspace computation in parallel manipulators with three

One of the weak aspects of the parallel robots is ratio between the workspace and the dimension of the mechanical structure, if compared with the serial one. Hence the shape of the workspace of a parallel manipulator is one of the most important aspects to reflect its working capacity. This paper introduces two innovative methods to analyze the workspace of some family of parallel robots, with the aim of highlighting its shape.

Approaches to the Determination of the Working Area of Parallel Robots and the Analysis of Their Geometric Characteristics

Engineering Transactions, 2019

The article presents and experimentally confirms two approaches to the problem of determining the working area of parallel robots using the example of a planar robot DexTAR with two degrees of freedom. The proposed approaches are based on the use of constraint equations of coordinates. In the first approach, the original kinematic equations of coordinates in the six-dimensional space (two coordinates describing the position of the output link and four coordinates – the rotation angles of the rods) followed by projecting the solution onto the two-dimensional plane is used. In the second approach, the system of constraint equations is reduced to a system of inequalities describing the coordinates of the output link of the robot, which are solved in a two-dimensional Euclidean space. The results of the computational experiments are given. As an algorithmic basis of the proposed approaches, the method of non-uniform coverings is used, which obtains the external and internal approximatio...

Orientation workspace verification for parallel kinematic machines with constant leg length

Compared to serial robots, parallel kinematic machines (PKM) offer superior properties. However, modelling and analysis of PKMs are challenging tasks due to their complicated kinematic structure. In this paper we present methods to analyze the workspace of a class of 6 degree-of-freedom (dof) PKMs with constant leg length. These methods apply interval analysis in order to calculate the orientation workspace and to verify if a certain machine covers a desired workspace. The machines are assembled from a construction kit that defines components like legs, frames, and platforms.

Workspace and Joint Space Analysis of the 3-RPS Parallel Robot

Volume 5A: 38th Mechanisms and Robotics Conference, 2014

The Accurate calculation of the workspace and joint space for 3 RPS parallel robotic manipulator is a highly addressed research work across the world. Researchers have proposed a variety of methods to calculate these parameters. In the present context a cylindrical algebraic decomposition based method is proposed to model the workspace and joint space. It is a well know feature that this robot admits two operation modes. We are able to find out the set in the joint space with a constant number of solutions for the direct kinematic problem and the locus of the cusp points for the both operation mode. The characteristic surfaces are also computed to define the uniqueness domains in the workspace. A simple 3-RPS parallel with similar base and mobile platform is used to illustrate this method.

A simplified approach for obtaining the workspace of a class of 2-dof planar parallel manipulators

Mechanism and Machine Theory, 1999

This paper presents a method for generating the reachable workspace of a class of planar two-degreeof-freedom (dof) end-eector-type manipulators. This class is based on six planar linkages with ®ve links and ®ve joints, revolute and/or prismatic. A common set of two quadratic equations is presented that determine the workspace of all the class as a function of the input motions of the manipulator under study. The quadratic equations involve only the Cartesian coordinates (x,y) of the operation point. Thus, the formulation is governed by the analytical solution of a well known second order equation and the inverse kinematic problem is not required. Because of the simplicity of the involved equations, an algorithm can be easily implemented on a computer program. Examples of generated workspaces for all the class are given to illustrate the proposed approach.

Workspace generation and planning singularity-free path for parallel manipulators

Mechanism and Machine Theory, 2005

This paper presents a numerical technique for path planning inside the reachable workspace of parallel manipulators avoiding singularity. A generic numerical algorithm for generating the reachable workspace of parallel manipulators is described. The singularity points are determined, grouped into several clusters and modelled as obstacles. A path planning algorithm is used to find an optimal path avoiding these obstacles. Isolated singularities are avoided using local routing method based on GrassmannÕs line geometry. Examples are demonstrated for the effectiveness of the algorithms. (I-Ming Chen). www.elsevier.com/locate/mechmt Mechanism and Machine Theory 40 (2005) 776-805

Enlarging operational workspaces in parallel manipulators by connecting working modes. Application to the 3 RSS robot

Robotica, 2012

SUMMARYThe aim of this paper is to describe a general methodology for enlarging the workspace within which a parallel manipulator can move in a controllable way. The basis for obtaining this consists in superimposing all the singularity-free regions associated with the various different robot working modes. These can be connected because such transitions do not imply a loss of control of the manipulator. This enlarged operational workspace is associated with a certain assembly mode. In addition, the strategy to be used for path planning in this kind of workspace is presented.

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.