Modeling And Dynamic Testing Of A Space Link Antenna Drive Mechanism

With the increasing demand of high cover TT&C and huge communication bandwidth,Many countries are establishing TDRSS(tracking and data relay satellites system),to provide high reliability tracking and data relay for satellites and other spacecraft or ground TT&C stations.The satellite antennas are demanded more and more to be assembled into the normal satellites and TDRSS.The driving mechanism is the most important equipment for continuous tracking of target,so it is necessary to establish the model of antennas driving mechanism,and find the General ground test method.In this thesis,the research content includes: the working principle introduction of a driving mechanism,the motor modeling study,drive modeling research,transmission system modeling analysis,space interference torque analysis,the model correctness verification based on real control software,semi-physical simulation test system design and implementation.Firstly,this thesis introduces the components and working principle of a antennas driving mechanism.In terms of step motor modeling,use the internal magnetic flux as state variables to model has some certain limitation.So,this thesis uses the motor inductance as state variables.To avoid the difficulty of incomplete parameter,so as to achieve the better applicability.Combined with the established motor drive model,the simulink dynamic simulation model has been established.By motor measurement data,the equivalent coefficient of torque saturation threshold and increment in the single-phase stator permanent magnet flux amplitude has been determined.The contrast of real torque-frequency characteristics and simulation characteristics proves the correctness of the model.With the modification of the model,the simulink model can be used for simulation analysis of other step motors.In terms of transmission system modeling,the usual approach is to use proportion link to replace it,as torque amplifier and velocity reducer.In this thesis,on the basis of digesting and absorbing domestic and foreign research results,considering the flexible characteristic of harmonic gear reducer,flexible and rigid tooth meshing characteristics,rotor rotation process between the friction characteristics and transmission clearance,a more complete and strong adaptability of harmonic gear reducer model has been established.In the aspect of system simulation,a complete mathematical model of the movement process of the driving mechanism is established.It contains motor model,drive model,transmission model,the on-orbit disturbing torques model.As the same time,finite element model is established,and the top five order vibration mode is given.In the aspect of antennas driving mechanism ground test method research,this thesis analysis the limitation of the traditional momentum wheel test method and full-scale test method,the semi-physical test method is put forward and the equipment is complete.Practice shows that the device can greatly reduce consumption of resources.This thesis' s innovation mainly has two points: Firstly,digital simulation model is established and its correctness is verified.In the subsequent course of the development of other satellite,it can advance to prove the validity of the control algorithm,improve the efficiency of drive control software development,reduces the time of the satellite development.Secondly,ground testing scheme of a satellite antenna driving mechanism is put forward and used to complete the equipment.With this equipment,in different antenna loading cases,the dynamic characteristic of the driving mechanism can be tested,a lot of costs can be saved.