A novel planar parallel manipulator with high orientation capability for a hybrid machine tool: kinematics, dimensional synthesis and performance evaluation

Abstract

SUMMARYIn order to potentially realize the advantages of planar parallel manipulators to be used for hybrid machine tools, the inherently abundant singularities which diminish the usable workspace must be eliminated. Proper structure synthesis and dimensional synthesis can provide a good solution. So, a non-conventional architecture of a three-PPR planar parallel manipulator is proposed in this paper for a hybrid machine tool. The proposed architecture permits a large dexterous workspace with unlimited orientation capability and no singularities. It also provides partially decoupled motion which permits independent actuators control. The kinematic, singularity, orientation capability and workspace analyses of the proposed manipulator are studied to verify those advantages. Based on a non-dimensional design parameter space, the highly important indices for this application namely the workspace index (WI), the motion/force transmission index, the kinematic and dynamic dexterity indices and the stiffness index are selected to be maximized yielding proper dimensions of the design parameters. Those performance indices are proven to be uniform over all the workspace achieving highly important characteristics of uniform accuracy, acceleration characteristics, rigidity and force transmissibility. Performance evaluation is finally presented to verify the high performance of the proposed non-singular planar parallel manipulator with high orientation capability.

An approach for elastodynamic modeling of hybrid robots based on substructure synthesis technique

“…Static and dynamic compliances are two important performance factors of parallel kinematic machines (PKMs) [1][2][3][4][5] especially for those dedicated to metal cutting, high-speed milling or drilling for example, where high rigidity and high dynamics are crucially required. Since static and dynamic behaviors are highly pose-dependent within the work envelop [6][7][8][9][10][11], the development of effective techniques for dynamic modeling is of great importance in the design optimization as well as in the cutting stability prediction. Literature reveals intensive investigations in the past decades towards dynamic modeling of PKMs.…”

Dynamic Modeling of a 2-RPU+2-UPS Hybrid Manipulator for Machining Application

“…Huang et al (2011) developed a configuration of a 3-P(4R)S-XY hybrid machine tool and derived the error model and error kinematics. Lu et al (2014) proposed a 6-DOF 3-UPS parallel manipulator with multiple fingers; their manipulator has three fingers installed on a moving platform, which decreases interference and enlarged its In addition, Assal (2015) designed a planar parallel manipulator with high orientation ability for a hybrid machine tool. Wu et al (2015b) established an effective dynamic model that took into consideration the deformation of the flexible link of the heavy duty parallel manipulator.…”