Kinematic Analysis and Dimensional Synthesis of Exechon Parallel Kinematic Machine for Large Volume Machining

Abstract

A parallel kinematic machine (PKM) topology can only give its best performance when its geometrical parameters are optimized. In this paper, dimensional synthesis of a newly developed PKM is presented for the first time. An optimization method is developed with the objective to maximize both workspace volume and global dexterity of the PKM. Results show that the method can effectively identify design parameter changes under different weighted objectives. The PKM with optimized dimensions has a large workspace to footprint ratio and a large well-conditioned workspace, hence justifies its suitability for large volume machining.

Kinematics and Constraints of the Exechon Robot Accounting Offsets Due to Errors in the Base Joint Axes

“…Eqs. (10) and (11) are in terms of unknowns k, e x and θ . Two sets of closed-form solutions for k and e x in terms of θ can be obtained, however the expressions are two long to be presented in this paper.…”

“…Note that O r E = (e x , −k sin α, k cos α), therefore, finding e x , k and α solves the FKP since α also defines Oĵ E and using Eqs. (10) and (11), θ would be obtained which allows the computation of Oî E and Ok E . To obtain equations involving e x , k and α two expressions for point B 2 are written.…”

“…In addition to the applications of the Exechon robot, its striking topology has called the attention of many researchers who have worked in studying its kinematics [10,11,12], stiffness [13,14,15,16], constraint space and singularities [17,18], dimensional synthesis [11], equivalent PKMs [19].…”

QrPara: A New Reconfigurable Parallel Manipulator with 5-Axis Capability

“…Although the two modes have the same types of mobility, but their workspace envelops are quite different. Mode I mechanism can be regarded as a positioning mechanism as it has a large reachable workspace with very small rotational capability [21]. While in Mode II, the mechanism has large rotational capability as the rotational axes (B 1 B 3 and y e ) are both on the moving platform, but much smaller positioning workspace as B 1 B 3 is constrained in the fixed plane A 1 B 1 B 3 A 3 .…”

“…By alternatively locking different sets of lockable joints, QrPara can be used as both positional and orientational PMs with the same set of actuators. The idea is steming from the Exechon PM, which has a large reachable workspace used for positioning although it has two rotational and 1 translational DOF [21]. By locking three passive revolute joints on the base and adding three passive revolute joints connected to the moving platform, the RPM will perform as an orientational PM which has large tilting capability.…”