Kinematic analysis of limited-dof parallel manipulators based on translational/rotational Jacobian and Hessian matrices

Robotica ◽  
2009 ◽  
Vol 27 (7) ◽  
pp. 971-980 ◽  
Author(s):  
Yi Lu ◽  
Yan Shi ◽  
Jianping Yu
Keyword(s):  
Kinematic Analysis ◽  
Jacobian Matrix ◽  
Parallel Manipulators ◽  
Parallel Kinematic Machines ◽  
Parallel Kinematic

SUMMARYThis paper proposes an approach for solving the velocity and acceleration of the limited-dof (dof n < 6) parallel kinematic machines with linear active legs by means of translational/rotational Jacobian and Hessian matrices. First, based on the established or derived constraint and displacement equations, the translational/rotational Jacobian and Hessian matrices are derived. Second, the formulae for solving inverse/forward velocities and accelerations are derived from translational and rotational Jacobian/Hessian matrices. Third, a 2SPR + UPU PKM and a 2SPS + RPRR PKM are illustrated for explaining how to use this method. This approach is simple because it needs neither to eliminate 6-n rows of an n × 6 Jacobian matrix nor to determine the screw or pose of the constrained wrench.

On the Structural Constraint and Motion of 3-PRS Parallel Kinematic Machines

2021 ◽  
Author(s):  
Hassen Nigatu ◽  
Yun Ho Choi ◽  
Doik Kim
Keyword(s):  
Jacobian Matrix ◽  
Constraint Equation ◽  
Parallel Manipulators ◽  
Forward Rate ◽  
Structural Constraint ◽  
Usual Practice ◽  
Parasitic Motion ◽  
Parallel Kinematic ◽  
Joint Velocity ◽  
Velocity Level

Abstract This paper presents a consistent analytic kinematic formulation of the 3-PRS parallel manipulator (PM) with a parasitic motion by embedding the velocity level structural constraint equation into the motion expression. Inverse rate kinematics (IRK) is solved with a simple constraint compatible velocity profile, which is obtained by projecting the instantaneous restriction space onto the motion space. Moreover, the systematic method to reveal the parasitic motion is introduced. Thus, the parasitic terms are automatically identified from the main motions. Unlike the usual approach, this study does not consider any explicit parasitic motion expression. Consequently, the derivation of constraint compatible input velocity, which comprises the parasitic term, is simplified. To incorporate the parasitic motion into the task velocity, constraint Jacobian of the manipulator is analytically obtained first. The manipulator Jacobian is extended to incorporate the passive joint’s information apart from the active joints and structural constraint. Hence, the dimension of the Jacobian matrix used to solve IRK is 9 × 6. The validity of the IRK is proved by the Bordered Gramian based forward rate kinematics (FRK). Then, an accurate numerical integration, RK4, is applied to the joint velocity of IRK to obtain the manipulator’s joint values. Consequently, the moving plate’s pose is obtained via forward position kinematics computed using integrated active and passive joint values for validation. The projection matrix used to get compatible constraint motion adjusts our input velocity and makes it compatible with the structural constraint policy, and the parasitic motion is embedded easily. Thus, an explicit formulation of the parasitic motion equation is not required, as the usual practice. Finally, the study presented numerical simulations to show the validity of the outlined resolutions. This paper’s result and analysis can be uniformly applied to other parallel manipulators with less than 6 DoFs.

The SOCs Modular Method for Kinematic Analysis of Complicated Parallel Manipulators

2011 ◽  
Vol 52-54 ◽  
pp. 834-841
Author(s):  
Zhi Xin Shi ◽  
Mei Yan Ye ◽  
Yu Feng Luo ◽  
Ting Li Yang
Keyword(s):  
Kinematic Analysis ◽  
Parallel Manipulators ◽  
Initial Guess ◽  
Modular Approach ◽  
Compatibility Conditions ◽  
Kinematic Chains ◽  
Procedural Approach ◽  
Modular Method ◽  
Parallel Kinematic

This paper presents a simple and systematic modular approach for kinematic analysis of complicated Parallel Kinematic Manipulators (in short, PKMs) which coupled degrees are more than 2. (1) Single open chains (in short, SOCs) may be regarded as the basic modules of a PKM. Any PKM can always be decomposed automatically into a set of ordered SOCs, and these SOCs can also be used to recognize the basic kinematic chains contained in it. (2) The kinematic analysis algorithms and the compatibility conditions of the SOC modules are offered. (3) Directly applying the above SOC kinematic modules, the kinematic equations of a PKM can be automatically established. (4) In order to solve kinematic equations of complicated parallel manipulators which coupled degrees are more than 2, a new searching algorithm which requires no initial guess has been presented. The procedural approach is demonstrated in parallel manipulators.

Kinematic Analysis of a Novel 3-DOF Parallel Mechanism with Actuation Redundancy

2013 ◽  
Vol 816-817 ◽  
pp. 821-824
Author(s):  
Xue Mei Niu ◽  
Guo Qin Gao ◽  
Zhi Da Bao
Keyword(s):  
Kinematic Analysis ◽  
Parallel Mechanism ◽  
Rbf Neural Network ◽  
Analysis Method ◽  
Parallel Kinematic Mechanism ◽  
Redundantly Actuated ◽  
Parallel Kinematic ◽  
Forward Kinematic ◽  
Kinematic Mechanism ◽  
Kinematic Solution

Kinematic analysis plays an important role in the research of parallel kinematic mechanism. This paper addresses a novel forward kinematic solution based on RBF neural network for a novel 2PRRR-PPRR redundantly actuated parallel mechanism. Simulation results illustrate the validity and feasibility of the kinematic analysis method.

On the Solutions of Interval Systems for Under-Constrained and Redundant Parallel Manipulators

2017 ◽  
Vol 9 (6) ◽  
Author(s):  
Leila Notash
Keyword(s):  
Least Squares ◽  
Jacobian Matrix ◽  
Parallel Manipulators ◽  
Constrained Systems ◽  
Solution Set ◽  
Least Squares Solution ◽  
Interval Linear ◽  
Interval Linear Systems ◽  
Parameter Dependency ◽  
Interval Systems

For under-constrained and redundant parallel manipulators, the actuator inputs are studied with bounded variations in parameters and data. Problem is formulated within the context of force analysis. Discrete and analytical methods for interval linear systems are presented, categorized, and implemented to identify the solution set, as well as the minimum 2-norm least-squares solution set. The notions of parameter dependency and solution subsets are considered. The hyperplanes that bound the solution in each orthant characterize the solution set of manipulators. While the parameterized form of the interval entries of the Jacobian matrix and wrench produce the minimum 2-norm least-squares solution for the under-constrained and over-constrained systems of real matrices and vectors within the interval Jacobian matrix and wrench vector, respectively. Example manipulators are used to present the application of methods for identifying the solution and minimum norm solution sets for actuator forces/torques.

scholarly journals Conceptual design and comparative stiffness analysis of an Exechon-like parallel kinematic machine with lockable spherical joints

2017 ◽  
Vol 14 (4) ◽  
pp. 172988141772413
Author(s):  
Teng-fei Tang ◽  
Jun Zhang
Keyword(s):  
Conceptual Design ◽  
Prediction Accuracy ◽  
Parallel Kinematic Machine ◽  
Stiffness Analysis ◽  
Parallel Kinematic Machines ◽  
Stiffness Model ◽  
Dynamic Analyses ◽  
Parallel Kinematic ◽  
Kinetostatic Model ◽  
Limb Structure

This article proposes two types of lockable spherical joints which can perform three different motion patters by locking or unlocking corresponding rotational axes. Based on the proposed lockable spherical joints, a general reconfigurable limb structure with two passive joints is designed with which the conceptual designs of two types of Exechon-like parallel kinematic machines are completed. To evaluate the stiffness of the proposed Exechon-like parallel kinematic machines, an expanded kinetostatic model is established by including the compliances of all joints and limb structures. The prediction accuracy of the expanded stiffness model is validated by numerical simulations. The comparative stiffness analyses prove that the Exe-Variant parallel kinematic machine claims competitive rigidity performance to the Exechon parallel kinematic machine. The present work can provide useful information for further investigations on structural enhancement, rigidity improvement, and dynamic analyses of other Exechon-like parallel kinematic machines.

Kinematic-, Static- and Workspace Analysis of a 6-P-U-S Parallel Manipulator

2010 ◽  
Author(s):  
Madusudanan Sathia Narayanan ◽  
Sourish Chakravarty ◽  
Hrishi Shah ◽  
Venkat N. Krovi
Keyword(s):  
Structural Design ◽  
Parallel Manipulators ◽  
Type I ◽  
Kinematic Modeling ◽  
Workspace Analysis ◽  
Reaction Forces ◽  
Specific Configuration ◽  
Parallel Kinematic ◽  
Stewart Gough Platform

This paper examines the symbolic kinematic modeling of a general 6-P-U-S (prismatic-universal-spherical) parallel kinematic manipulator (PKM). The base location of actuators has been previously shown to lead to: (i) reduction of the (motor) weight carried by the legs; (ii) elimination of the actuation transmission requirement (through intermediary joints as in the case of the Stewart-Gough platform); and (iii) most-importantly absorption of reaction-forces by the ground. We focus on using the symbolic equations to derive the conditions for type I and II singularities of this class of parallel manipulators. Based on these conditions, this system of equations is specialized to a specific configuration of the platform that has superior structural design and comparatively minimal singularities within its workspace. A series of studies were conducted to investigate the quality of workspace as well as estimate the actuation requirements for a unit payload carried over their workspace using the symbolic Jacobian model for this specialized configuration.

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