Computer-aided structural synthesis of 5-DOF parallel mechanisms and the establishment of kinematic structure databases

• Programmable structure representation for parallel mechanisms is proposed.
• 5-DOF limb database with essential constraint characteristics is established.
• Computer-aided structural synthesis of 5-DOF parallel mechanisms is proposed.
• Kinematic structure databases of 5-DOF parallel mechanisms are established.
• Two promising 5-DOF parallel mechanisms applied to CT scanner are achieved.

Structural synthesis is one of the most important steps in the conceptual design of mechanisms and robots. The existing synthesis methods for spatial mechanisms are mainly performed by manual enumeration, which is hard to realize the automation and computerization of the conceptual design of mechanisms and robots. This paper proposes a computer-aided method for the synthesis of both symmetrical and asymmetrical 5-DOF parallel mechanisms and the establishment of corresponding kinematic structure databases, which is conductive to kinematic structure design in human–computer interaction. First, a new structural representation is proposed, with which the complete topological information of a parallel mechanism can be represented by a string convenient for computer processing. Then, the computerized synthesis of 5-DOF limbs is performed and the corresponding limb database is established. Third, a computer-aided synthesis method for 5-DOF parallel mechanisms is developed and the corresponding kinematic structure databases are established. Finally, based on the databases, the structural design of 5-DOF parallel mechanisms applied to computed tomography (CT) scanners is conducted, illustrating the effectiveness of the method.