A postprocessing and path optimization based on nonlinear error for multijoint industrial robot-based 3D printing

Abstract

Multijoint industrial robots can be used for 3D printing to manufacture the complex freeform surfaces. The postprocessing is the basis of the precise printing. Due to the nonlinear motion of the rotational joint, nonlinear error is inevitable in multijoint industrial robots. In this article, the postprocessing and the path optimization based on the nonlinear errors are proposed to improve the accuracy of the multijoint industrial robots-based 3D printing. Firstly, the kinematics of the multijoint industrial robot for 3D printing is analyzed briefly based on product of exponential (POE) theory by considering the structure parameters. All possible groups of joint angles for one tool pose in the joint range are obtained in the inverse kinematics. Secondly, the nonlinear error evaluation based on the interpolation is derived according to the kinematics. The nonlinear error of one numerical control (NC) code or one tool pose is obtained. The principle of minimum nonlinear error of joint angle is proposed to select the appropriate solution of joint angle for the postprocessing. Thirdly, a path smoothing method by inserting new tool poses adaptively is proposed to reduce the nonlinear error of the whole printing path. The smooth level in the smoothing is proposed to avoid the endless insertion near the singular area. Finally, simulation and experiments are carried out to testify the effectiveness of the proposed postprocessing and path optimization method.

Machining with a Precision Five-Axis Machine Tools Created by Combining a Horizontal Parallel Three-Axis Motion Platform and a Three-Axis Machine Tools

“…Liu and Huang [ 15 ] examined the nonsingular tool path generation of TriMule, which is a five-axis hybrid robot, and observed sudden changes in the rotation of the C -axis and the lengths of three telescopic legs. Fu et al [ 16 ] proposed a postprocessing and path optimization method based on a nonlinear error to improve the precision of multijoint industrial robot-based three-dimensional (3D) printing. Guo et al [ 17 ] developed a control system designed for a new five-DoF hybrid robot manipulator and described the mechanical structure, kinematics, dynamics, and control system of the robot manipulator.…”