Papers by Keyword: Parallel Kinematic Machine (PKM)

Abstract: Parallel kinematic machine tools (PKM) are developed to increase dynamic parameters for high speed and high accuracy machining to gain short lead times and high productivity. One of the most important components of machine tools is the numerical controller (NC). Most NCs are organized in a cascaded structure, comprising the position, velocity and current loops. Commonly applied servo controllers generate tracking errors in each axis. These tracking errors are a significant factor that affects machining accuracy, beside geometric machine errors, vibrations, temperature changes and tool errors. In this paper the contour error originated from servo tracking controller in Cartesian kinematic machine tools (CKM) with perpendicular arranged machine axes and PKM is presented. The effects of the forward transformation of the tracking errors in PKM are addressed with experiment and simulation results. The servo tracking effect on trace accuracy is discussed by a tripod mechanism and radial deviations are measured with double ball bar method (DBB).

Abstract: The paper describes the definition of a set of generalized coordinates and forces (kinematic control parameters) necessary to satisfy a specific job. Specifically, the generation of a three dimensional curve with torsion described by a Frenet reference system. The method employed to accomplish this task is using the Original ADAMS program alias MCADA. The analysis results indicate that the method can be successfully applied when designing motion simulators; however, there are accuracy restrictions for high precision six axis machining.

Abstract: Today, Parallel Kinematic Machine tools (PKMs) appear in automotive and aeronautic industry. These machines propose high kinematic performances allowing a higher productivity than Serial Kinematic Machine tools (SKMs). However, this kinematic behaviour is anisotropic and a particular study is then necessary to locate the part in a workspace where the kinematic performances are well exploited. The study presented in this article deals with the determination of geometric and kinematic models of a new PKM : the Tripteor X7 designed by PCI. The inverse kinematic model expresses the joint coordinates with regard to the cartesian coordinates. The kinematic model which takes into account velocity, acceleration and jerk limits axis, allows computing the displacement time between two tool positions. Finally, this model can be used to determine the workspace where Non Effective cutting Times (TNE) are minimum. The method is applied for an automotive part machining

Abstract: This paper obtained the inverse kinematics model through performing kinematic analysis of 6-DOF parallel kinematic machine (PKM) via the MATLAB software. On the basis of that, kinematics inverse module in EMC2(Enhanced Machine Controller) is recompiled and verified through CNC machining simulation, which set up an important foundation for later prototype construction and motor output control.

Abstract: The existence of the non-compensable errors in limited-degree-of-freedom (limited-DoF) parallel kinematic machines (PKMs) affects the accuracy of mechanism and decreases the location capability. A 3-PRS parallel manipulator as an example, this paper formulates the mathematical model of the accuracy synthesis of the manipulator and carries out the accuracy synthesis based on the genetic algorithms, and then obtains the tolerance range of the non-compensable errors in the manufacture and the assembly.

Abstract: The parallel kinematic machines have broad application prospects in the manufacturing industry. Good dynamic characteristics are needed for the structure, which has direct influence on working efficiency, stability and reliability. ANSYS software analysis of their dynamic characteristics is accurate and easy, and can quickly modify the design fault and reduce design cost. In this paper Pro/Engineer is used to draw the solid model of PKM and assembly each part to constitute a system. At last the whole system is imported into ANSYS. The finite element model is established with the simplified model and element equivalent simulation, and modal analysis is conducted using model vibration theory and finite element theory. After the vibration deformation analysis of whole system, the weak parts, i.e. each bearing joint and the power transmission chains, are identified. The weak parts can then be enforced to improve the dynamic characteristics of the whole system.

Abstract: A new parallel kinematic machine UPS-2RPS with serial input limb is presented, the topological structure characteristics are described. The mathematic model of inverse position solution is derived. The workspace of the mechanism is analyzed and researched by results of MATLAB and Pro/E simulation, The research will be of great significance to promote its novation, application and spread .