Kinematics of a 6-DOF parallel manipulator with two limbs actuated by spherical motion generators

2021 ◽  
pp. 095440622110329
Author(s):  
Kun Wang ◽  
Xiaoyong Wu ◽  
Yujin Wang ◽  
Jun Ding ◽  
Shaoping Bai
Keyword(s):  
Kinematic Analysis ◽  
Parallel Manipulator ◽  
Parallel Manipulators ◽  
Practical Application ◽  
Numerical Examples ◽  
Position Analysis ◽  
Kinematic Study ◽  
Small Footprint ◽  
Dual Arm ◽  
Spherical Motion

Inspired by dual-arm-like manipulation, a novel 6-DOF parallel manipulator with two spherical-universal-revolute limbs is proposed. Compared with general 6-DOF parallel manipulators with six limbs, this new manipulator actuated by spherical motion generators has only two limbs, which brings advantages such as fewer active limbs for avoiding interference, larger reachable and orientational workspace for complex operating, more actuators integrated in active modules for decreasing installation errors and increasing compactness. In this paper, the kinematics of this novel parallel manipulator is solved and illustrated, covering its inverse and forward position analysis, workspace and singularities. The kinematic study reveals interesting features of this manipulator such as multiple working and assembly modes, small footprint and large workspace volume with high dexterity. Numerical examples of kinematic analysis are included. Practical application of the new manipulator is illustrated.

Kinematics and Dynamics of a Parallel Manipulator With Woven Joints

1993 ◽  
Author(s):  
Hyunsok Pang
Keyword(s):  
Lagrange Multipliers ◽  
Kinematic Analysis ◽  
Inverse Kinematics ◽  
Parallel Manipulator ◽  
Inverse Dynamics ◽  
Numerical Technique ◽  
Vector Analysis ◽  
Kinematics And Dynamics ◽  
Governing Equations ◽  
Numerical Examples

Abstract Presented is an analysis of the kinematics and the inverse dynamics of a proposed three DOF parallel manipulator resembling the Stewart platform in a general form. In the kinematic analysis, the inverse kinematics, velocity and acceleration analyses are performed, respectively, using vector analysis and general homogeneous transformations. An algorithm to solve the inverse dynamics of the proposed parallel manipulator is then presented using a Lagrangin technique. In this case, it is found that one should introduce and subsequently eliminate Lagrange multipliers in order to arrive at the governing equations. Numerical examples are finally carried out to examine the validity of the approach and the accuracy of the numerical technique employed. The trajectory of motion of the manipulator is also performed using a cubic spline.

Direct Position Analysis in Analytical Form of Parallel Manipulators Generating Structures With Topology SR-2PS

2004 ◽  
Author(s):  
Raffaele Di Gregorio
Keyword(s):  
Parallel Manipulator ◽  
Parallel Manipulators ◽  
Analytical Form ◽  
Solution Procedure ◽  
Generic Structure ◽  
Kinematic Chains ◽  
Position Analysis ◽  
In Series ◽  
The One ◽  
Wide Family

A wide family of parallel manipulators (PMs) is the one that groups all the PMs with three legs where the legs become kinematic chains constituted of a passive spherical pair (S) in series with either a passive prismatic pair (P) or a passive revolute pair (R) when the actuators are locked. The topologies of the structures generated by these manipulators, when the actuators are locked, are ten. One out of these topologies is the SR-2PS topology (one SR leg and two PS legs). This paper presents an algorithm that determines all the assembly modes of the structures with topology SR-2PS in analytical form. The presented algorithm can be applied without changes to solve, in analytical form, the direct position analysis of any parallel manipulator which generates a SR-2PS structure when the actuators are locked. In particular, the closure equations of a generic structure with topology SR-2PS are written. The eliminant of this system of equations is determined and the solution procedure is presented. Finally, the proposed procedure is applied to a real case. This work demonstrates that the solutions of the direct position analysis of any parallel manipulator which generates a SR-2PS structure when the actuators are locked are at most eight.

A new family of spherical parallel manipulators

Robotica ◽  
2002 ◽  
Vol 20 (4) ◽  
pp. 353-358 ◽  
Author(s):  
Raffaele Di Gregorio
Keyword(s):  
Parallel Manipulator ◽  
Parallel Manipulators ◽  
End Effector ◽  
Singular Configurations ◽  
New Family ◽  
Geometric Conditions ◽  
Singularity Locus ◽  
The Given ◽  
Spherical Parallel Manipulator ◽  
Spherical Motion

In the literature, 3-RRPRR architectures were proposed to obtain pure translation manipulators. Moreover, the geometric conditions, which 3-RRPRR architectures must match, in order to make the end-effector (platform) perform infinitesimal (elementary) spherical motion were enunciated. The ability to perform elementary spherical motion is a necessary but not sufficient condition to conclude that the platform is bound to accomplish finite spherical motion, i.e. that the mechanism is a spherical parallel manipulator (parallel wrist). This paper demonstrates that the 3-RRPRR architectures matching the geometric conditions for elementary spherical motion make the platform accomplish finite spherical motion, i.e. they are parallel wrists (3-RRPRR wrist), provided that some singular configurations, named translation singularities, are not reached. Moreover, it shows that 3-RRPRR wrists belong to a family of parallel wrists which share the same analytic expression of the constraints which the legs impose on the platform. Finally, the condition that identifies all the translation singularities of the mechanisms of this family is found and geometrically interpreted. The result of this analysis is that the translation singularity locus can be represented by a surface (singularity surface) in the configuration space of the mechanism. Singularity surfaces drawn by exploiting the given condition are useful tools in designing these wrists.

scholarly journals Kinematic Analysis Of Tricept Parallel Manipulator

2012 ◽  
Vol 12 (5) ◽  
Author(s):  
Mir Amin Hosseini ◽  
Hamid-Reza Mohammadi Daniali
Keyword(s):  
Kinematic Analysis ◽  
Parallel Manipulator ◽  
Parallel Manipulators ◽  
Degree Of Freedom ◽  
Geometric Constraints ◽  
Design Parameters ◽  
Forward Kinematics ◽  
Jacobian Matrices ◽  
Moving Platforms ◽  
Workspace Optimization

Parallel manipulators consist of fixed and moving platforms connected to each other with some actuated links. They have some significant advantages over their serial counterparts. While, they suffer from relatively small workspaces, complex kinematics relations and highly singular points within their workspaces. In this paper, forward kinematics of Tricept parallel manipulator is solved analytically and its workspace optimization is performed. This parallel manipulator has a complex degree of freedom, therefore leads to dimensional in-homogeneous Jacobian matrices. Thus, we divide some entries of the Jacobian by units of length, thereby producing a new Jacobian that is dimensionally homogeneous. Moreover, its workspace is parameterized using some design parameters. Then, using GA method, the workspace is optimized subjects to some geometric constraints. Finally, dexterity of the design is evaluated. Keywords- Kinematic, Workspace, Singularity, TriceptABSTRAK - Manipulator selari terdiri daripada platform tetap dan bergerak yang bersambung antara satu sama lain dengan beberapa pautan bergerak. Manipulator selari mempunyai beberapa kebaikan tertentu dibandingkan dengan yang bersamaan dengannya. Walaupun ia mempunyai ruang kerja yang sempit, hubungan kinematik kompleks dan titik tunggal tinggi dalam linkungan ruang kerjanya. Dalam kajian ini, kinematik ke hadapan manipulator selari Tricept diselesaikan secara analisa dan pengoptimuman ruang kerja dijalankan. Manipulator selari ini mempunyai darjah kebebasan yang kompleks, yang menyebabkan ia mendorong kepada kehomogenan dimensi matriks Jacobian. Catatan Jacobian dibahagikan kepada unit panjang, dimana ia menghasilkan Jacobian baru yang homogen dimensinya. Tambahan, ruang kerjanya diparameterkan dengan menggunakan beberapa parameter reka bentuk. Kemudian, dengan kaedah GA, ruang kerja mengoptimakan subjek kepada beberapa kekangan geometrik. Akhirnya, kecakatan reka bentuk dinilaikan.Keywords- Kinematic, Workspace, Singularity, Tricept

Design and Kinematic Analysis of a Novel 7-DoF Dual-Arm Parallel Manipulator for 3C Products Assembly

2021 ◽  
pp. 290-301
Author(s):  
Xiansheng Yang ◽  
Zhenyu Zou ◽  
Jinmin Zhang ◽  
Yunjiang Lou
Keyword(s):  
Kinematic Analysis ◽  
Parallel Manipulator ◽  
Dual Arm

Comparative Kinematic Analysis and Design Optimization of Redundant and Nonredundant Planar Parallel Manipulators Intended for Haptic Use

Robotica ◽  
2019 ◽  
Vol 38 (8) ◽  
pp. 1463-1477 ◽  
Author(s):  
Houssem Saafi ◽  
Houssein Lamine
Keyword(s):  
Design Optimization ◽  
Kinematic Analysis ◽  
Parallel Manipulator ◽  
Kinematic Model ◽  
Parallel Manipulators ◽  
Geometric Parameters ◽  
Analysis And Design ◽  
Planar Parallel Manipulator ◽  
Forward Kinematic ◽  
Planar Parallel Manipulators

SUMMARYThis paper investigates a comparative kinematic analysis between nonredundant and redundant 2-Degree Of Freedom parallel manipulators. The nonredundant manipulator is based on the Five-Bar mechanism, and the redundant one is a 3-RRR planar parallel manipulator. This study is aimed to select the best structure for a haptic application. This latter requires a mechanism with a desired workspace of 10 cm × 10 cm and an admissible force of 5 N in all directions. The analysis criteria are the accuracy of the forward kinematic model and the required actuator torques. Thereby, the geometric parameters of the two structures are optimized in order to satisfy the required workspace such that parallel singularities are overcome. The analysis showed that the nonredundant optimally designed manipulator is more suitable for the haptic application.

A New Algorithm Based on Two Extra-Sensors for Real-Time Computation of the Actual Configuration of the Generalized Stewart-Gough Manipulator

1998 ◽  
Author(s):  
V. Parenti-Castelli ◽  
R. Di Gregorio
Keyword(s):  
Real Time ◽  
Parallel Manipulator ◽  
Parallel Manipulators ◽  
Computational Burden ◽  
The Real ◽  
Position Analysis ◽  
Extra Information ◽  
Actual Configuration ◽  
General Geometry

Abstract It is well known that the direct position analysis of fully-parallel manipulators provides more than one solution, i.e., more than one configuration of the mechanism is possible for a given set of the actuated variables of motion. Extra information is, thus, necessary to find the actual configuration of the manipulator. This paper presents a new algorithm for the real-time computation of the actual configuration of the generalized Stewart-Gough manipulator, also known as 6-6 fully-parallel manipulator with general geometry. The proposed algorithm makes use of two extra rotary sensors in addition to the six normally implemented in the servosystems of the manipulator. A one-to-one correspondence between the sensor measurements and the manipulator configuration is provided. With respect to other algorithms recently presented in the literature, the proposed method greatly reduces the computational burden. Finally a case study shows the effectiveness of the proposed procedure.

Design and Singularity Analysis of a 3-Translational-DOF In-Parallel Manipulator*

2002 ◽  
Vol 124 (3) ◽  
pp. 419-426 ◽  
Author(s):  
L. Romdhane ◽  
Z. Affi ◽  
M. Fayet
Keyword(s):  
Kinematic Analysis ◽  
Parallel Manipulator ◽  
Parallel Manipulators ◽  
Singularity Analysis ◽  
Orientation Error ◽  
Kinematic Chains ◽  
Prismatic Joints ◽  
Forward Kinematic ◽  
3D Solid ◽  
Novel Design

In this work, we shall present a novel design of a 3-translational-DOF in-parallel manipulator having 3 linear actuators. Three variable length legs constitute the actuators of this manipulator, whereas two other kinematic chains with passive joints are used to eliminate the three rotations of the platform with respect to the base. This design presents several advantages compared to other designs of similar 3-translational-dof parallel manipulators. First, the proposed design uses only revolute or spherical joints as passive joints and hence, it avoids problems that are inherent to the nature of prismatic joints when loaded in arbitrary way. Second, the actuators are chosen to be linear and to be located in the three legs since this design presents higher rigidity than other. In the second part of this paper, we addressed the problem of kinematic analysis of the proposed in-parallel manipulator. A mixed geometric and vector formulation is used to show that two solutions exist for the forward kinematic analysis. The problem of singularities is also investigated using the same method. In this work, we investigated the singularities of the active legs and the two types of singularity were identified: architectural singularities and configurational singularities. The singularity of the passive chains, used to restrict the motion of the platform to only three translations, is also investigated. In the last part of this paper, we built a 3D solid model of the platform and the amplitude of rotation due to the deformation of the different links under some realistic load was determined. This allowed us to estimate the “orientation error” of the platform due to external moments. Moreover, this analysis allowed us to compare the proposed design (over constrained) with a modified one (not over constrained). This comparison confirmed the conclusion that the over constraint design has a better rigidity.

Analysis of static equilibrium of a parallel manipulator

Robotica ◽  
1993 ◽  
Vol 11 (5) ◽  
pp. 433-443 ◽  
Author(s):  
Hyunsok Pang ◽  
Mohsen Shahinpoor
Keyword(s):  
Parallel Manipulator ◽  
Numerical Technique ◽  
Parallel Manipulators ◽  
Stewart Platform ◽  
Static Equilibrium ◽  
Force Distribution ◽  
Numerical Examples ◽  
Generalized Force

SUMMARYAn analysis is presented in this paper for the equilibrium of a class of parallel manipulators resembling the Stewart platform in a general form. General coordinates and 4 x 4 homogeneous transformations are employed to arrive at exact expressions for the force distribution in all six legs given the general 6-dimensional wrench (generalized force) at the upper platform of a parallel manipulator. Numerical examples are carried out to examine the validity of the approach and the accuracy of the numerical technique employed.

Singularity and Controllability Analysis of Parallel Manipulators

1998 ◽  
Author(s):  
Prasun Choudhury ◽  
Ashitava Ghosal
Keyword(s):  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Equations Of Motion ◽  
Parallel Manipulators ◽  
Joint Space ◽  
Transformation Matrix ◽  
Constraint Forces ◽  
Numerical Examples ◽  
Cartesian Space ◽  
Force Transformation

Abstract This paper presents a study of kinematic and force singularities and their relationship to the controllability of planar and spatial parallel manipulators. Parallel manipulators are classified according to their degrees of freedom, number of output Cartesian variables used to describe their motion and the number of actuated joint inputs. The singularities in the workspace of a parallel manipulator are studied by considering the force transformation matrix which maps the forces and torques in joint space to output forces and torques in Cartesian space. The uncontrollable regions in the workspace of the parallel manipulator are obtained by deriving the equations of motion in terms of Cartesian variables and by using techniques from Lie Algebra. We show that when the number of actuated joint inputs is equal to the number of output Cartesian variables, and the force transformation matrix loses rank, the parallel manipulator is uncontrollable. For the case of manipulators where the number of joint inputs is less than the number of output Cartesian variables, if the constraint forces and torques (represented by the Lagrange multipliers) become infinite, the force transformation matrix loses rank. Finally, we show that the singular and uncontrollable regions in the workspace of a parallel manipulator can be reduced by adding redundant joint actuators and links. The results are illustrated with the help of numerical examples where we plot the singular and uncontrollable regions of parallel manipulators belonging to the above mentioned classes.

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