A multi-Bennett 8R mechanism obtained from factorization of bivariate motion polynomials. (February 2023)

• Record Type: Journal Article
• Authors: Frischauf, Johanna; Pfurner, Martin; Scharler, Daniel F.; Schröcker, Hans-Peter
• Is Part Of: Mechanism and machine theory. Volume 180(2023)
• Publication Date: 2023-02
• Subjects: Dual quaternions -- Bennett mechanism -- Motion polynomial -- Factorization -- Aligned configuration; Machine theory -- Periodicals; Machinery -- Periodicals; Machines -- Périodiques; Génie mécanique -- Périodiques; Machine theory; Machinery; Periodicals; 621.81
• DOI: 10.1016/j.mechmachtheory.2022.105143
• Languages: English
• ISSNs: 0094-114X

Abstract

Abstract: We present a closed-loop 8R mechanism with two degrees of freedom whose motion exhibits curious properties. In any point of a two-dimensional component of its configuration variety it is possible to fix every second joint while retaining one degree of freedom. This shows that the even and the odd axes, respectively, always form a Bennett mechanism. In this mechanism, opposite distances and angles are equal and all offsets are zero. The 8R mechanism has four "totally aligned" configurations in which the common normals of any pair of consecutive axes coincide. Highlights: New closed-loop 8R linkage by factorization of bivariate quaternion polynomial. All offsets are zero, opposite distances and angles are equal. Locking every second joint in any configuration retains one degree of freedom. Four configurations where all axes intersect a straight line orthogonally.