Program design of an online dynamic balancing system for grinding-wheel and spindle
For unbalance of grinding wheel and spindle system in high-speed grinding process, an online dynamic balancing program is proposed. Firstly unbalance factors during grinding process are analyzed, and vibration features excited by these centrifugal forces are defined. Based on these works, technologies on wheel-spindle online dynamic balancing are introduced, including sensor selection and setting, vibration signal and phase angle measurement, signal amplification and analog filtering, A/D conversion, digital filtering, unbalance solution, dynamic balancing device and its drive and control. Finally, a wheel-spindle online dynamic balancing program is designed, which will have a good engineering application prospect in CNC machine spindle system.
The investigation of unbalanced vibration in flexible motorized spindle-rotor system
ABSTRACT Unbalance is a significant concern for spindle-rotor dynamic systems and an important problem in high-speed machining. An active control scheme with built-in force actuator is proposed for unbalanced vibration of flexible motorized spindle-rotor, which is to improve the performance of high-speed machining system. At first, the motorized spindle motor with built-in force actuator and flexible motorized spindle-rotor are designed and then the experiment setup based on digital signal processor for controlling actively the unbalanced vibration of flexible spindle-rotor is tailored. Finally, the active vibration control scheme is investigated experimentally based on previous theoretical studies. The experimental results prove the feasibility of the active control scheme.
Automatic balancing of flexible rotors, part I: Theoretical background
Some possibilities of automatization of flexible rotors balancing with controlled balancing heads are set out in this paper. A computer is proposed to be the controller. With help of modal analysis of the vibrations generated by unbalance forces a relationship between successive positions of the correction masses is determined. Some calculation procedures for control laws governing the shifting of correction masses in Cartesian or polar co-ordinate systems are introduced. A solution is proposed as to the problem of passing through critical speeds.