| In space launch missions,all kinds of separation devices are used to release satellites,fairings and solar panels.Due to high reliability,non-pyrotechnic separation device is the earliest and the commonest.However,its releasing shock is high.With the development of small satellite,the sensitivity of internal elements in the small satellite is higher and higher.The high releasing shock of traditional non-pyrotechnic separation device causes the damage to sensitive elements.In this paper,we developed a high-load,quick releasing,low-shock and reusable non-pyrotechnic separation device driven by DC motors and used for separating the satellite from the launch vehicle.Firstly,we studied load distribution of threads basing on the bearing theory of a complete nut engaged with a bolt.Then,the bearing capacity of two-sectional incomplete segmented nut is studied on the static load condition.We studied the relation between tightening torque and preload during tightening the bolt.These results establish theoretical basis for the subsequent design and test.Then,according to the requirements about the bearing capacity,the separating time and releasing shock,a new non-pyrotechnic separation device is established by Solid Works.The function of connection and separation is achieved by releasing clamps(which are also regarded as two-sectional incomplete segmented nuts)whose motion is controlled by four-bar mechanism.Two redundant DC motors are utilized for actuators to unlock 8 balls,which are designed for locking the device.As for the 3-dementional model of separation device,the bearing capacity of separation device is verified by simulation using ANSYS.In order to verify that unlocking mistakenly by external vibration excitation occur or not,pre-stressed modal analysis is studied.In addition,the process of unlocking and separation is simulated by ADAMS.On the basis of the above,the separation device prototype is fabricated.Then,some tests are proposed to verify the performance,including bolt preload calibration test,separating time test,releasing shock test,and high and low temperature test.The results indicate that the separation device can meet all requirements,like high-load,quick releasing and separation,low-shock,high and low temperature resistance and reusable. |
