Parallel kinematic concept for stationary high performance cutting in wood machining centers

Abstract

In recent years parallel kinematic machines for wood machining have come into use more frequently. Despite first promising prototypes, these machines are single solutions for specific applications. To meet the requirements of shorter product life cycles and higher product diversity, high flexibility is demanded of the machining system. This paper presents a new wood machining center obtaining both, the reduction of the primary and secondary processing times. The machine concept, based on a parallel kinematic structure, allows high operating speeds and accelerations not only for workpiece machining but also for handling. Thus, the machine can be used without any external handling devices. The kinematic structure originates from a plane closed five-bar chain with two linear drives and additional drive axes for stroke and rotation. In order to increase the useable workspace a continuous motion between different assembly modes is realized. To guarantee a high feed rate and to minimize setup times, an optimized dust exhaustion is included.

Configuring a Class of Machines Based on Reconfigurable 2DOF Planar Parallel Mechanism

“…Each unit represents theoretically attainable workspace for each of the two solutions of direct kinematics problem. By extending the actuated axes pitch, two partial workspaces would merge into one workspace, whereby the entire workspace would be extended, and avoiding singularity and changing the sign of kinematics problems can be realized in one of the manners as described in [23]. Figures 5 and 6 also show useful workspaces of the regular shape for configurations of the mechanisms For previously defined useful workspaces, simulation of the loaded G-code is presented first, and thereafter the analysis of distribution of the Jacobian matrix determinant det(J) of analyzed mechanism configuration MOMA.…”

“…Using the advantages of hybrid mechanisms, many authors provide solutions for the development of machine tools that are based on a combination of serial and parallel mechanisms. Papers [17][18][19] show hybrid machine tools based on a parallel mechanism with translatory actuated joints, while in papers [20][21][22][23] authors propose hybrid mechanisms that include the parallel mechanism based on rotary axes.…”

How to Expand the Workspace of Parallel Robots

“…Researches on expanding the workspace by the mode change of the parallel robot have been reported for nonredundant two-dof planar robot [4,5], nonredundant three-dof spatial translational robot [6], redundantly driven three-dof translational and rotational planar robot [7], and redundantly driven three-dof spatial translational robot [8]. Redundant actuation is the actuation in one of the most effective methods for avoiding the singularity.…”

Mode changes of redundantly actuated asymmetric parallel mechanism

“…By changing configurations from one solution to another, the PKM can expand its workspace. [2][3][4][5][6][7] The configuration changes are categorized into two types. In the working mode change, the PKM changes configurations from one inverse kinematics solution to another.…”