| As the important component of CNC machine tools, feed drive system has agreat influence on the performance of CNC machine tools. At present, the ball screwfeed drive systems are adopted in most of the CNC machine tools, therefore, thefurther study on dynamic performance of the ball screw feed drive system has veryimportant significance to the development of CNC machine tools. In the process ofhigh speed running, the ball screw feed drive mechanism with long and thin screwwill produce vibrations, and the vibrations will affect the stability of the controlsystem and reduce the processing speed and accuracy of CNC machine tools. At thesame time, in order to control or compensate this vibrations, accurate vibrationmodal parameters are needed. So it is necessary to study on the modal parameteridentification method and the vibration suppression method of ball screw feed drivesystem.Focusing on the measurement, identification of modal parameter and vibrationcontrol of ball screw in high speed feed drive system, this thesis carried outtheoretical and experimental studies of the system. What main done included:(1) An experimental platform of dynamic characteristics was established, Thevibration signals under the condition of work were got through high resolutionrotary encoder and linear encoder, combining with high-speed counter.(2) The theory of wavelet analysis and modal parameter identification werediscussed and the modal parameter identification method based on Morlet waveletwere tested and verified through simulation. Furthermore, using this method, themodal parameters of the ball screw were identified through the speed/accelerationresponse signals of the feed drive systems which were measured in the process ofrunning.(3) A dynamic model of the ball screw feed drives including torsional and axialvibrations was built. The numerical calculation was conducted using MATLABsoftware. Combining the results of numerical calculation, mechatronic integratedsimulation and experiment, the results showed that rolling vibration of ball screw had important influence on the dynamic performances of feed drive system.(4) A mechatronic integrated simulation framework of the ball screw feeddrive system was built using MATLAB and ADAMS software, and the principle ofactive damping control was analyzed theoretically. Finally, an active dampingcontrol module was added to the mechatronic integrated simulation framework,which realized the suppression of rolling vibration presented in this thesis, thus thedynamic performance of feed drive system was improved. |
