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The laser tracker is composed of a mechanical structure and a servo control system. And the characteristics of them all affect the error and stability of the laser tracker measurement system. In the dynamic characteristics, the mechanical structure has its natural frequency and the servo control system has servo bandwidth. If the natural frequency closes to the servo bandwidth, the noise produced by system will have an influence on the stability and measure precision of the turntable. In order to make a laser tracker take a good performance, the natural frequency has to stay away from the range of the servo bandwidth. Based on this relationship between the natural frequency and servo bandwidth, construct and simplify a 3D model, analyze the influence of material stiffness, friction and rotary inertia on the natural frequency of a self-developed laser tracker turntable. Analysis shows that the natural frequency augments with the increase of material stiffness and reduction of rotary inertia and has nothing to do with friction. And factors of the structure material influence the different orders of natural frequency differently. These conclusions show that the kind of material with low density and high stiffness is more fitted to the turntable and provide references for optimization design of precision laser tracking turntable.
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