To suppress the abrupt and unexpected turning velocity fluctuation of the industrial robot under the condition of trajectory tracking, a flexible robotic joint experimental setup with the harmonic drive was established. The measured friction with Stribeck effect and velocity were modeled by a simple polynomial fit method. Two friction compensation control strategies of feedforward and feedback were designed. The friction compensation experiments were carried out on the dSPACE system, the good restraint effect of fluctuation on the turning velocity was verified and the control accuracy of feedback compensation control strategy proved better.

Rotor axis orbit measurement of the spindle under cutting process is the important basis of cutting quality judgment and spindle fault diagnosis. In the cutting process, the non-stationary characteristics of vibration measurement signal of spindle rotor has been particularly outstanding, under such circumstances it is difficult to draw spindle rotor axis orbit accurately. To solve this problem, a new method using EEMD (Ensemble Empirical Mode Decomposition) and harmonic wavelet is put forward to realize non-stationary signal purification and rotor axis orbit feature extraction under machine tool spindle cutting process. In order to filter out the high frequency noise of the measurement, the EEMD method has been used, in addition that the characteristics of the original signal is preserved well. However the signal after EEMD filter still contains a variety of frequency components, in order to solve it, the harmonic wavelet method is used to decompose the signal into several signals according to the different frequency components, through the signal reconstruction achieve rotor axis orbit feature extraction. Using this method, the machined workpiece has been cut under the speed of 12000r/min, the vibration of spindle has been measured and processed. The experiment results show that the new method can effectively reduce the high frequency interference noise signal, and also apparently the rotor axis orbit obtained is more clearly than the original rotor axis orbit.

The vibration of grinding wheel spindle will significantly reduce the machining quality and machining accuracy of precision grinding. In order to suppress the grinding wheel rotor vibration effectively, the Spray-Typed online dynamic balance system for specific grinding wheel spindle was designed composed of terminal balance, hydraulic system and control system. To achieve the amount of spindle unbalance accurate extraction and liquid volume control, using hydraulic system to achieve the balance of the terminal of the liquid loading and using high-performance DSP chip as a control method. A segmented spindle online dynamic balance method , combining the advantages of influence coefficient method and coordinate rotation optimization method was proposed. The method can fast approaching the goal of balancing and meet the local precise adjustment of the balance weight. At last, the online dynamic balance experiment of grinding wheel spindle is carried out in the industrial field, the grinding spindle vibration displacement amplitude decreased from 17.8 to 7.7 before and after balance, fall by as much as 55%, which verifies the validity and feasibility of the system.