TY JOUR TI STRUCTURAL SYNTHESIS OF PARALLEL MECHANISMS THAT PROVIDE PLANE-PARALLEL MOTION OF THE OUTPUT LINK BASED ON THE THEORY OF SCREWS AND VIRTUAL KINEMATIC CHAINS KW parallel mechanism KW kinematic chain KW the theory of screws KW virtual circuit. JO Bulletin of Belgorod State Technological University named after. V. G. Shukhov AU Gaponenko , E.. AU Rybak , L.. AU Malyshev , D.. PY 2017 IS 2 PB Belgorod State Technological University named after V.G. Shukhov