Design of Compliant Universal Joint With Linear Stiffness

This paper mainly presents a novel compliant universal joint with linear stiffness (CUJ-LS). This new type of architecture can maintain the linear stiffness while realizing two rotational DOFs. And the planar topology ensures that the rotation axis remains through the center of the moving platform, thus deducing the moment of inertia. According to the Freedom and Constrain Topology (FACT) theory, this paper firstly proposes a topological structure of the compliant universal joint. Then the stiffness model is established by the Beam Constraint Model (BCM) and the condition of achieving linear stiffness is derived: λ = 0.1273/0.8727. By introducing the intermediate platforms, the linear stiffness in two directions of rotation is realized. Finally, FEA method is implemented to verify and analyze the rotation performances of this compliant universal joint. Verified characteristics provide conditions for the applications of compliant universal joint in laser communication, antenna pointing, infrared tracking and aiming, laser processing, precision measurement and other fields which require high-speed, high-acceleration and high precision characteristics.