Influence Of Non-regular Clearance On Dynamic Performance Of The Two-axes Position Mechanism For Satellite Antenna

Friction and wear is one of the main factors which can cause the reduction,or even the failure of the performance and accuracy of space mechanism. Considering the spacecraft constructions'need for high reliability and durability, this paper makes a deep research on the features of satellites'friction and the influnces that brought by non-regular clearance which is caused by friction on dynamic characteristics, taking the two-axes-position mechanism for satellite antenna for object.Firstly, establish a dynamic model of the two-axes-position mechanism for satellite antenna with clearance. The introduction of vector clearance makes a correct discription of bearing clearance and then the contact dynamics model is built based on the nonlinear equivalent spring-damp model, considering the friction effect using corrected coulomb friction model. By introducing step function, contact force caused by clearance and friction are embedded into the dynamics model of ideal kinematic pair, and then the dynamic model of the two-axes-position mechanism for satellite antenna with clearance is established.Secondly,establish a virtual prototype model of the two-axes-position mechanism based on the three-dimensional modeling tool pro/E and multi-body dynamics simulation software adams. Applying the three-dimensional solid model, rigid,Simple Pairs is defined by Interface Program mech/pro and then introduced into dynamics simulation software adams to process the complex pairs. From the methods mentioned above, the virtual prototype model of the two-axes-position mechanism is created and then, proved correctly by verification.Furthermore, systematically analyse the influences that brought by clearance and other factors on the dynamics characteristic of the two-axes-position mechanism. Embedes clearance into virtual prototype so as to establish the model of the virtual prototype model of the two-axes-position mechanism with clearance and make dynamics simulation. According to the simulating result, analysis on the influence of dynamics characteristic which caused by clearance and its evolution law induced by different factors are carried out. Finally, reconstruct the wear morphology of joint with clearance, then analyse the influences that brought by wear clearance. basing on the simulation results of virtual prototype, the dynamics parameters are proposed. The wear is obtained by utilizing archard's model, so as to acquire wear depth with corresponding to each point of the working surface. The introduction of polar coordinate vectors to achieve the Wear morphology of joint. The reconstruction of wear morphology is realized to analyze the influence of satellite antenna's dynamics characteristic caused by non-regular wear clearance.