Studies On Transmission Precision And Dynamic Characteristics Of Harmonic Reducer

A harmonic reducer is a key component of the spacecraft transmission system, to accomplish the task of movement, transmission torque and body connection, and it is the key part of aerospace machinery to guarantee precision, carrying capacity, moving safety and stability in the process of movement. However, the dynamics theory of nonlinear friction, motion precision, and hysteretic stiffness is not perfect, and restrict the development of aerospace machinery seriously.Therefore, the paper has developed the motion precision and dynamic characteristic test platform of harmonic reducer, and designed nonlinear friction experiment, motion precision experiment and hysteresis stiffness experiment, to study the dynamics characteristics of harmonic reducer. This paper focused on the following four aspects of work:1) Developed the motion precision and dynamic characteristic test platform of harmonic reducer, and can do nonlinear friction experiment, motion precision experiment and hysteresis stiffness experiment. The test platform scalability is stronger.2) Established Coulomb-Stick-Stribeck friction model under the conditions of low and ultra-low speeds, and identified the parameters of Coulomb-Stick-Stribeck friction model based on the experimental data, further analyzed the influence of key parameter to the friction characteristics.3) Mapped the hysteretic stiffness curve of harmonic reducer, and discovered the hysteretic stiffness has nothing to do with flexspline workstation, and discovered the law of the torsional rigidity under different torque.4) The paper considers the variable stiffness in the harmonic gear and proposes an equivalent dynamic model based on the chain of equivalent stiffness, damping and rotational inertia. We studied the influences of stiffness, damping, and rotational inertia of the harmonic drive on transmission error through the numerical simulation. And the correctness of the dynamic model hae been verified by experiment.The above research may be useful for designing harmonic drive and conceiving strategies for precision improvement.