Structural Design And Experimental Study On The Defect Detector For Large Caliber Sphere And Non-sphere Surface

With the development of high precision optical technology,optical element with sphere and non-sphere surface has been used more and more widely,at the same time,the requirements of surface flaw detection for high precision optical became more and more strict.Thus the demand of the defect detector which can detect flaw for large caliber spherical and non-spherical optical element appeared.At present,the defect detect system and equipment mainly used for large caliber element or plane element,the study on the flaw detect equipment for spherical optical element is rare,which is difficult to achieve high precision detect of non-spherical optical element.However,it can’t satisfy the demand of large caliber spherical and non-aspheric optical element surface flaw detection.In this paper,the mechanical structure of the defect detector for large caliber spherical and non-spherical optical element has been designed to meet the detect requirements of surface flaw,on the basis of a relatively mature optical detect manner.In order to guarantee the rationality of the mechanical structure and shorten the prototype development cycles,the simulation analysis of mechanical structure was done,and related mathematical model was established.After a prototype of the defect detector has been successfully manufactured,flaw detection experiments were conducted to verify the ability of the defect detector.The main work content of this paper are summarized as follows:1.Analyzed the various parameters and interface requirements of mechanical structure which is necessary to achieve high precision surface flaw detection,combined with the parameters of large caliber spherical and non-spherical optical elements and optical detect method.Determined the layout form of high precision defect detector refer to the general structure of optical detect equipment,aiming at the existing conditions,and considering the operatio n difficulty and cost factors.At the same time,the mechanical structure of each part type was selected with the mainly structure part was designed to satisfied the functional requirements of the defect detection,the structure design of the defect detector was completed.2.The simulation analysis of mainly structure of the defect detector has carried on,it is concluded the stress and deformation of key component in the optical test system and its micro adjust mechanism under static load conditions.On the basis of the result,structure design was optimized to lighten the load and reduce the influence of detect precision by the deformation;Modal analysis of key component in the optical test system and its micro adjust mechanism and complete machine was conducted to obtain the first 6 order natural frequency of the mainly structure.Compared with the motor operating frequency,the natural frequency is much higher,which ensure that resonance vibration will not occur and the probe will not jitter in the process of detecting,too.The results guarantee the stability of the structure and the rationality of the design.3.The rigid model of the defect detector mechanical structure was established based on the theory of multi-body system.The low-order array and the topology structure were used to describe the design feature of the defect detector.the kinematics model and the accuracy model of the defect detection was put forward.The path of moving axis inversion could realize through the kinematics model of the defect detector,and facilitating computer automatically calculation the axes trajectory according to the form of optical elements.According to the accuracy model of the defect detection and typical non-spherical optical element as an example,error compensation was calculated.The result forecasts the accuracy of the defect detector,verifies the rationality of the overall mechanical structure,and provides the basis for the defect detector error compensation.4.Assemble and test all motion axis and the machining parts.Besides,error parameters was calibrated and indicated.The operate steps of the defect detector was made.The flaw image get from the fault detection experiment verifies the ability of the defect detector.