Modeling of a Ti/NiTi spring-blade gear for space micro-vibration isolation

Space pointing mechanisms are crucial in space scientific experiments and observations. Since the precision of such mechanisms is highly susceptible to micro-vibrations due to environmental disturbances and inherent defects, isolating micro-vibrations is important. A low rotational stiffness spring-blade gear installed on the output shaft of the stepper motor can isolate micro-vibrations due to the motor's discontinuous rotation. However, a quantitative performance description is still lacking. In this paper, a rotational stiffness model for the spring-blade gear made of titanium and nickel-titanium-based shape memory alloy is established and experimentally validated. A vibration transmissibility model is developed, revealing the relationships among the layout, material properties, structural parameters, external loads, rotational stiffness, and vibration transmissibility of the spring-blade gear. This paper can be used to design and optimize the spring-blade gear, predicting the isolation and suppression capability against micro-vibrations at different frequency ranges. The optimal gear structure can be obtained according to vibration isolation requirements, load, and installation constraints to achieve the predetermined vibration isolation effect. This study can ensure the space pointing mechanisms operate with high precision and stability by attenuating space micro-vibrations effectively, improving the quality of signal acquisition and observation accuracy.