The Vibration Control And Measurement For The Cabin Supporting Structure Of Large Radio Telescope

The works in the paper are parts of research work on the Large Radio Telescope(LT). Two parts are mainly concerned here: Vibration control of cabin and measurement.Firstly. Vibration control is the main research work in the paper. The followed work have been done:1. The static equilibrium equation for the Cabin Supporting Structure is solved by iteration, which could make the six cables loaded very closely. Based on the shape of the static balance, the dynamic response of the Cabin Supporting Structure is analyzed under the stochastic wind.2. The characters of the MTMD are analyzed. The tuned mass, amount, the damper ratio and tuned frequency spacing are the main influencing parameters to the vibration control. The effects of MTMD for vibration control with different parameters are analyzed for the single-freedom structure and multiple-freedom structure like cabin supporting structure.3. The GA (Genetic Algorithm) is applied to solve the optimal parameters of the MTMD appended in cabin in frequency-domain.4. The dynamic responses of the cabin with different MTMD are compared under different wind speed. Based on the analysis, the optimal MTMD with most effective parameters in time-domain is got, which could suppresses the vibration of cabin effectively.5. The dynamic characters of LT are analyzed when the cabin is located at different position on the working trace. The applicability of the MTMD for the cabin located at different position is discussed.6. Suppressing the vibration actuated by the six motors when the cabin moves along the working trace. The MTMD for the different positions are designed based on the Fourier analysis. The experiment shows that the MTMD with rectified parameters could suppress the vibration of cabin.7. When the cabin located on different working position is inducedto vibrate by some accidental instantaneous impacting load, the MTMD could attenuate the cabin's vibration very quickly. Secondly. In order to realize the close-loop control to the cabin, three target points on the cabin must be got to solve the position and orientation of the cabin. Two methods are introduced to realize the precise measurement and the wavelet is applied to reduce the errors of the measured coordinates:1. Stereo Vision: three CCD cameras are applied to get the coordinates of three target points on the cabin. Every camera could trace two points, and two cameras could position a point. Dual-mode tracing methods and other rectified techniques are introduced to realize tracing precisely.2. Three Leica TCA1100 Laser Total Stations are utilized to trace and measure the center of the three reflecting prisms. The coordinates of the three targets could be got by translation and rotation of reference-system.3. There are errors during the measurement for both methods. The wavelet is introduced to de-noise the measured coordinates due to its sensitivity to the white noise on different scales. More precise coordinates of the cabin could be got after de-noise by wavelet.The analysis and experiments show that two parts of research work are effective and could be reference to LT.