Grid fin translation mechanism is the key actuator of trajectory and attitude control in reentry flight of the reusable launch vehicle. The kinetic characteristic of translation mechanism is investigated experimentally. An experimental device and experimental schemes comprise position test, transient state test and frequency test are set up. The linear displacement of servo piston rod and the angle displacement of rudder shaft are measured by the displacement sensors. Firstly, the cause of linear displacement abrupt change in position test and angle displacement vibration in transient state test is studied. Furthermore, small shaft turning angle frequency test in low, mid and high frequency are tested and the angle displacement signal delay are comparativly analyzed. The clearances in kinematic pairs are considered as the important affecting factor of kinetic characteristic of translation mechanism and its influencing mechanism is preliminarily proposed. The results provide research object and experimental fundament for farther dynamic analysis and optimal design of transmission mechanism.

An experimental apparatus was designed to test the pivoting friction moment of annular friction disc under either constant normal force and variable normal force. The experimental results demonstrated the applicability of the classical pivoting friction model under the continuous variable normal contact force, and showed that the rotary velocity affects the properties of the pivoting friction. By considering the Stribeck effect of the local friction at a contact point, a theoretical model was proposed for the pivoting friction. Good agreement between proposed theoretical and experimental results sheds light on the physical mechanism underlying the pivoting friction.