Analysis of Oscillation Frequency Deviation in Elastic Coupling Digital Drive System and Robust Notch Filter Strategy

Abstract

Mechanical resonance is a common problem in drive systems with elastic coupling. On-line adaptive notch filter is widely used to make system stable and the key of this method is to identify natural torsional frequency from speed feedback signal. However, because of common adoption of digital control and expansion of system bandwidth, oscillation frequency of the system is more likely to deviate from natural torsional frequency to a higher one. When oscillation frequency is shifted, the enabled notch filter with erroneous notch frequency causes an oscillation with a lower frequency and even makes resonance severer. In order to explain this phenomenon, the classical two-mass model based classification of resonances is checked at first. Then, by taking digital control, current loop delay and saturation nonlinearity into consideration, an improved digital mechanical resonance model is proposed and a criterion for oscillation frequency deviation is finally obtained. Furthermore, a more widely applicable and robust notch filter tuning strategy with no oscillation rebound is presented. In the end, the validity of aforementioned analysis and strategy is verified by experimental results.

Electrical discharge machining of ceramic nanocomposites: sublimation phenomena and adaptive control

“…Because low-frequency vibrations (10–100 Hz) are associated with the appearance of low-frequency noise related to the work of the equipment and guiding bars and high-frequency oscillations (1500–8000 Hz) are associated with the wire tool vibrations and high-frequency noise (close to whistle) accompanying processing, it is recommended that EDM takes place outside the specified zone to exclude the phenomenon of resonance [178]:0.7<ωfrcωslf<1.3.…”

Control Method of Flexible Manipulator Servo System Based on a Combination of RBF Neural Network and Pole Placement Strategy

“…In the servo system for flexible manipulators, it is considered in the literature [30] that the control of the speed loop and current loop of the servo system has been completed. Therefore, the influence of the current loop and speed loop is ignored in this paper and considers position control.…”

“…Besides, the input torque is closely associated with the gravity term. In this paper, according to Equation (25), Equation (30), and Equation ( 31), the relationship between input torque and time under different manipulators' lengths is respectively calculated in two conditions, as shown in Figure 8. One of the cases ignores the gravitational factor, and the other case considers the gravitational factor.…”

Review on Embedded Methods in Parameter Estimation and Auto-tuning of Permanent Magnet Synchronous Servo Machine Driven Industrial Systems

“…According to servo system complexity, there can be more than one disturbance such as low frequency vibrations, resonance, periodic oscillations etc., with different frequencies and amplitudes. Online adaptive notch filter (OANF), iterative tuning of notch filter and robust online adaptive notch filter (ROANF) versions are used to solve these problems [64]- [66]. The general structure of a notch filter in the embedded servo system and a 2 nd order specific notch filter design is given in Fig.…”