A general C2 continuous toolpath corner smoothing method for a 5-DOF hybrid robot. (March 2022)

• Record Type: Journal Article
• Authors: Li, Guangxi; Liu, Haitao; Liu, Sijiang; Xiao, Juliang
• Is Part Of: Mechanism and machine theory. Volume 169(2022)
• Publication Date: 2022-03
• Subjects: CNC computer numerical control -- PS parameter synchronization -- 3D three-dimensional -- CAM computer-aided manufacturing -- CL cutter location -- WCS workpiece coordinate system -- CP characteristic parameter -- DOF degree of freedom -- C2CH the C2 continuity method by Huang; Corner smoothing -- Orientation error -- Five-axis machining -- Hybrid robot -- B-spline curve; Machine theory -- Periodicals; Machinery -- Periodicals; Machines -- Périodiques; Génie mécanique -- Périodiques; Machine theory; Machinery; Periodicals; 621.81
• DOI: 10.1016/j.mechmachtheory.2021.104640
• Languages: English
• ISSNs: 0094-114X

Abstract

Highlights: A C 2 continuous corner smoothing method for the five-axis toolpath is proposed. The smoothing errors can be analytically derived. The parameters are synchronized by reparameterizing the remaining path segments. Margins of the remaining path segments can be evaluated by a unified expression. The method is verified by simulations and experiments on the TriMule-800 robot. Abstract: The general five-axis toolpath, which consists of lines (or G01 commands) and arcs (or G02/G03 commands), is discontinuous in tangency or curvature at the transition points. The discontinuities will result in deteriorated machining efficiency and quality for the hybrid robot in high-speed machining. Therefore, toolpath smoothing techniques should be implemented. This paper proposes a semi-analytical C 2 continuous corner smoothing method. Three types of tool position transitions are addressed considering the error tolerances, and tool orientation smoothing is addressed as a special case of spatial arc-arc smoothing on the unit sphere surface. Based on the analytical smoothing error expressions, the inserted B-splines are generated by numerical algorithms. In addition, the remaining path segments are converted into specially designed quintic B-splines for parameter synchronization, and a unified expression is derived to evaluate their margins. Finally, a feedrate scheduling and interpolation algorithm is proposed for trajectory generation. Simulations and experiments are performed on the TriMule-800 hybrid robot to verify the effectiveness of the proposed method for generating smooth motion in the operational space or joint space.