System for controlling variable-setting blades for a turbine engine

System for controlling variable pitch vanes for a turbine engine, comprising at least one control ring mounted to freely rotate about a first annular casing with an axis of revolution A, at least one annular row of variable pitch vanes extending substantially radially relative to said axis A and being connected to said at least one control ring so that a rotation of the ring about the first casing sets the vanes into rotation about substantially radial axes B, and means for actuating said at least one ring so as to rotate it about the first casing, said actuation means being connected to said at least one ring by linking means comprising a shaft extending along an axis C that is substantially radial relative to said axis A and is mounted to freely rotate about said axis C on the first casing, characterised in that said shaft comprises a radially internal end mounted on the first casing by a pivot link or ball joint link and a radially external end connected by a pivot link or ball joint link to a fixed arm rigidly connected to a second casing or to the first casing.