Structure synthesis of 3-DOF translational parallel mechanisms with configurable platform of translation

The parallel mechanisms (PMs) with configurable platform have advantages of flexibility, high speed and extra operability over PMs with common platform. This paper proposes a systematic approach for synthesizing 3 degrees of freedom (DOF) translational parallel mechanisms with configurable platforms of one translation DOF (TPMs-T) based on the finite screw. The motion relationship between configurable platform and limbs is discussed to achieve the motion requirement of the TPMs-T limbs. The equivalence principle of kinematic joints is further pinpointed, and a series of lower mobility limbs have been developed. At last, the geometric relationship of assembly conditions is derived which can contribute to quickly solving the intersection of limb motions, a series of TPMs-T are constructed to verify the assembly conditions and the fully-controlled condition is discussed.