A method for extending planar axis-symmetric parallel manipulators to spatial mechanisms. (January 2015)

• Record Type: Journal Article
• Authors: Isaksson, Mats; Eriksson, Anders; Watson, Matthew; Brogårdh, Torgny; Nahavandi, Saeid
• Is Part Of: Mechanism and machine theory. Volume 83(2015:Jan.)
• Page Start: 1
• Page End: 13
• Publication Date: 2015-01
• Subjects: Parallel manipulator -- Linkage substitution -- Reciprocal screws -- Planar manipulator -- Axis-symmetric -- Rotation-symmetric; Machine theory -- Periodicals; Machinery -- Periodicals; Machines -- Périodiques; Génie mécanique -- Périodiques; Machine theory; Machinery; Periodicals; 621.81
• DOI: 10.1016/j.mechmachtheory.2014.08.014
• Languages: English
• ISSNs: 0094-114X

Abstract

Abstract: This paper investigates axis-symmetric parallel manipulators, composed of a central base column and an arm system able to rotate around this column. The arm system includes several actuated upper arms, each connected to a manipulated platform by one or more lower arm linkages. Such manipulators feature an extensive positional workspace in relation to the manipulator footprint and equal manipulator properties in all radial half-planes defined by the common rotation-axis of the upper arms. The similarities between planar manipulators exclusively employing 2-degrees-of-freedom (2-DOF) lower arm linkages and lower mobility spatial manipulators only utilising 5-DOF lower arm linkages are analysed. The 2-DOF linkages are composed of a link with a 1-DOF hinge on both ends whilst the 5-DOF linkages utilise 3-DOF spherical joints and 2-DOF universal joints. By employing a proposed linkage substitution scheme, it is shown how a wide range of spatial axis-symmetric parallel manipulators can be derived from a limited range of planar manipulators of the same type. Highlights: Axis-symmetric parallel manipulators provide several advantages. A methodology to derive axis-symmetric parallel manipulators is introduced. The core assumption of the proposed methodology is proved using screw theory. Several novel axis-symmetric parallel manipulators are proposed.