Classification of singular configurations for redundant manipulators

2002 ◽  
Author(s):  
N.S. Bedrossian
Keyword(s):  
Redundant Manipulators ◽  
Singular Configurations

Comparison of Damped Velocity and Acceleration Control for Non-Redundant Manipulators

2000 ◽  
Author(s):  
Yu-Che Chen ◽  
Kevin A. O’Neil
Keyword(s):  
Path Tracking ◽  
Least Square ◽  
Dynamics Simulation ◽  
Control Algorithms ◽  
Redundant Manipulators ◽  
Velocity Control ◽  
Redundant Manipulator ◽  
Singular Configurations ◽  
On Line ◽  
Simulation Results

Abstract Damped Least Square (DLS) method has been widely used as an on-line algorithm for manipulator path tracking near and at singular configurations. Wampler (1986) formulated the framework of DLS method applied to velocity control and addressed the applicability of DLS method to acceleration control. The purpose of this paper is to demonstrate the differences in the joint paths generated by damped velocity and damped acceleration control algorithms in non-redundant manipulators. We examine these joint paths, find the cause of the differences, and demonstrate the features of damped acceleration control in non-redundant manipulator dynamics. Simulation results on a planar 2R and a spatial 6R manipulator moving through and near singular configurations verify the phenomena analyzed.

Identification and classification of the singular configurations of mechanisms

1998 ◽  
Vol 33 (6) ◽  
pp. 743-760 ◽  
Author(s):  
D. Zlatanov ◽  
R.G. Fenton ◽  
B. Benhabib
Keyword(s):  
Singular Configurations

A new dynamic manipulability ellipsoid for redundant manipulators

Robotica ◽  
2000 ◽  
Vol 18 (4) ◽  
pp. 381-387 ◽  
Author(s):  
Pasquale Chiacchio
Keyword(s):  
Case Studies ◽  
Robotic Manipulators ◽  
Redundant Manipulators ◽  
Task Space ◽  
End Effector ◽  
Space Analysis ◽  
Singular Configurations ◽  
Definition Of

Manipulability ellipsoids are effective tools to perform task space analysis of robotic manipulators in terms of velocities, accelerations and forces at the end effector. In this paper a new definition of a dynamic manipulability ellipsoid for redundant manipulators is proposed which leads to more correct results in evaluating manipulator capabilities in terms of task-space accelerations. The case of manipulators in singular configurations is also analyzed. Two case studies are presented to illustrate the correctness of the proposed approach.

scholarly journals SINGULARITY ANALYSIS OF A 3-PRRR KINEMATICALLY REDUNDANT PLANAR PARALLEL MANIPULATOR

1970 ◽  
Vol 41 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Soheil Zarkandi
Keyword(s):  
Motion Control ◽  
Parallel Manipulator ◽  
Parallel Manipulators ◽  
Singularity Analysis ◽  
Redundant Manipulators ◽  
Static Behavior ◽  
Singular Configurations ◽  
Planar Parallel Manipulator ◽  
And Control ◽  
Planar Parallel Manipulators

Finding Singular configurations (singularities) is one of the mandatory steps during the design and control of mechanisms. Because, in these configurations, the instantaneous kinematics is locally undetermined that causes serious problems both to static behavior and to motion control of the mechanism. This paper addresses the problem of determining singularities of a 3-PRRR kinematically redundant planar parallel manipulator by use of an analytic technique. The technique leads to an input –output relationship that can be used to find all types of singularities occurring in this type of manipulators.Key Words: Planar parallel manipulators; Redundant manipulators; Singularity analysis; Jacobian matrices.DOI: 10.3329/jme.v41i1.5356Journal of Mechanical Engineering, Vol. ME 41, No. 1, June 2010 1-6

A DEPENDENT-SCREW SUPPRESSION APPROACH TO THE SINGULARITY ANALYSIS OF A 7-DOF REDUNDANT MANIPULATOR: CANADARM2

2005 ◽  
Vol 29 (4) ◽  
pp. 593-604 ◽  
Author(s):  
Xianwen Kong ◽  
Clément M. Gosselin
Keyword(s):  
Singularity Analysis ◽  
Degree Of Freedom ◽  
Redundant Manipulators ◽  
Redundant Manipulator ◽  
Singular Configurations

A dependent-screw suppression approach is proposed for the singularity analysis of 7-DOF (degree-of-freedom) redundant manipulators. This approach is applied to the singularity analysis of the Canadarm2. Five families of singular configurations are identified for the Canadarm2. The singular configurations obtained are identical to those obtained using the reciprocity-based method. Unlike the results presented previously, there are no denominators in the equations describing the singular configurations.

Classification of Screw Systems Composed of Three Planar Pencils of Lines for Singularity Analysis of Parallel Mechanisms1

2014 ◽  
Vol 6 (2) ◽  
Author(s):  
Xianwen Kong ◽  
Andrew Johnson
Keyword(s):  
Parallel Manipulators ◽  
Singularity Analysis ◽  
Degree Of Freedom ◽  
Spherical Joint ◽  
Geometric Characteristics ◽  
Singular Configurations ◽  
Kinematic Joint

Screw systems composed of (the sum of) three planar pencils of lines are closely related to the singularity analysis of a number of three-legged parallel manipulators (PMs) in which the passive joints in each leg are a spherical joint and a single-DOF (degree of freedom) kinematic joint or generalized kinematic joint. This paper systematically classifies the screw systems composed of three planar pencils of lines based on the intersection of two planar pencils of lines, the classification of screw systems of order 2, and the reciprocal screw system of the three planar pencils of lines. The classification in this paper is more comprehensive than those in the literature. The above results are illustrated using CAD figures. This work may help readers better understand the geometric characteristics of singular configurations of a number of three-legged parallel manipulators.

Applications of Damped Least-Squares Methods to Resolved-Rate and Resolved-Acceleration Control of Manipulators

1988 ◽  
Vol 110 (1) ◽  
pp. 31-38 ◽  
Author(s):  
C. W. Wampler ◽  
L. J. Leifer
Keyword(s):  
Least Squares ◽  
Rate Of Convergence ◽  
Sensory Feedback ◽  
Inverse Kinematic ◽  
Redundant Manipulators ◽  
Approximate Inverse ◽  
Singular Configurations ◽  
Large Joint ◽  
Resolved Acceleration Control ◽  
Damped Least Squares

Resolved-rate and resolved-acceleration controllers have been proposed for manipulators whose trajectories are determined by real-time sensory feedback. For redundant manipulators, these controllers have been generalized using the pseudoinverse of the manipulator Jacobian. However, near singular configurations, these controllers fail in that they require infeasibly large joint speeds. A damped least-squares reformation of the problem gives approximate inverse kinematic solutions that are free of singularities. Away from singularities the new controllers closely approximate their conventional counterparts; near singular configurations the new controllers remain well-behaved, although the rate of convergence decreases. This paper defines the new controllers and proves their stability. Some aspects of the behavior of the new resolved-rate controller are illustrated in simulations.

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