This paper addresses the kinematic sensitivity of the three degree-of-freedom 3-UPU parallel mechanism, a mechanism consisting of a fixed base and a moving platform connected by three serial UPU chains. Although a mathematical mobility analysis confirms that the mechanism has three degrees of freedom, hardware prototypes exhibit unexpected large motions of the platform even when the three prism...

In order to research kinematic reliability of 3-UPS-PU parallel mechanism, the structure and kinematics analysis were performed. Inverse kinematics equation can be derived by homogeneous coordinate transformation formula. Position and orientation output error forward kinematics model was obtained by the differential transformation on the basis of inverse kinematic solution of the position. The ...

In this study, we developed parallel link mechanisms by using multi-drive linear motors. Kinematics, dynamics, and control method of a three-degree-of-freedom (xyθ) planar parallel link mechanism with four redundant moving parts (3D4M mechanism) were investigated. A prototype of the 3D4M mechanism, which has decoupled dynamic characteristics, was developed. A notable kinematic characteristic of...

Parallel mechanisms frequently contain an unstable type of singularity that has no counterpart in serial mechanisms. When the mechanism is at or near this type of singularity, it loses the ability to counteract external forces in certain directions. This paper considers the application of additional kinematic constraint through passive joint braking in the close neighborhood of unstable poses. ...

This paper addresses the posture control problem for robotic systems subject to kinematic constraints. The key idea is to consider the kinematic constraints of the mechanisms from their structure equations, instead of Artigo submetido em 10/03/2011 (Id.: 01293) Revisado em 27/05/2011 Aceito sob recomendação do Editor Associado Prof. Carlos Roberto Minussi explicitly using the constraint equatio...

This paper presents a kinematic analysis and design characteristics of an in-parallel manipulator developed for the probing task application that requires high precision, active compliance, and high control bandwidth. The developed manipulator is a class of six-degree-of-freedom in-parallel platforms with 3 PRPS (prismatic-revolute-prismatic-spherical joints) chain geometry. The main advantages...

Error analysis is an important issue in parallel kinematic synthesis because manufacturing and assembly errors have a significant impact on the mechanical precision of the manipulator. In this paper we propose a method to describe the displacements of the tool center point (TCP) in terms of error amplifications for uncertainties in all kinematic parameters. This is done by using the differentia...

This paper presents a kinematic analysis of a parallel manipulator we have been developing for the probing task application that requires high bandwidth, active compliance, and high precision. Based on the concept of macro/micro manipulators, the parallel manipulator serves as a wrist of a macro manipulator. The developed manipulator is a class of in-parallel platforms with 3 PRPS( prismatic-re...

An initiative is undertaken by Bhabha Atomic Research Centre to extend affordable high quality neurosurgical practice in India. This automates the frameless Stereotaxy using a high precision 6 DOF Parallel Kinematic Mechanism (6D PKM) based Robot and a Surgical Coordinate Measuring Mechanism (SCMM). The system provides high accuracy as well as high patient comfort level as compared to conventio...

This paper focuses on the kinematic properties of a new three-degree-of-freedom hybrid manipulator. This manipulator is obtained by adding in series to a five-bar planar mechanism (similar to the one studied by Bajpai and Roth [1]) a third revolute passing through the line of centers of the two actuated revolute joints of the above linkage (Figures 2 & 3). The resulting architecture is hybrid i...