Updating structural synthesis methodology of mechanisms: from kinematic geometry to kinematic geometry accompanied with statics

Abstract

Mechanism is a device to transmit and convert motion, force, and energy. However, for a long time, the structural synthesis methodology using the instantaneity and continuity based methods with a total of 11 variants actually just discusses the kinematic geometry significance and losses the mechanic concern. It neglects to extract the force and energy characteristics from task's requirements, and may produce low-payload, weak-stiffness, or low-efficiency mechanisms. How to take full consideration of motion, force, and energy in structural synthesis has become a tough challenge for strongly-interactive and physically-intelligent applications in the new-generation robot community. Therefore, this study proposes a new structural synthesis methodology unifying kinematic geometry and statics, integrating continuity and instantaneity by developing the finite and instantaneous screw theory, and taking motion, force, and energy characteristics simultaneously to design moving platform, limb, and joint respectively. As an example, the 2R1T mechanism exerted by 1F1M loads is designed with good payload, interaction and transmission work efficiencies. By utilizing this methodology, the feasible topologies designed are actually very fewer than those obtained by kinematic geometry based methodology, which may behave weak payload and work efficiency during strong interaction.