11 Infinitesimal Mechanics of the PKMs
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Published:2018
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Consideration of the position error problem uses the models entered for solution of inverse kinematics for parallel-kinematics machines. Obviously, an actual motion of the moving platform of the li-DOF mechanism (li = 2 ÷ 6) is accompanied with the same sextet of position-orientation errors δxi, δyi, δzi, δθi, δψi, δφi, composing the twist δ for 1-DOF body. Since the set of drives of the moving platform is simultaneously served as a movement issue and as a suspension system, the moving platform can be modelled as a rigid body on six rigid supports whose supports are the limbs. Hence, the solution obtained for the guideways accuracy (Subsection 9.1.2.3) can be applied to the position accuracy problem of the moving platform of the parallel mechanism taking into account that: