The Research On The Control Method Of Compliant Coupled Loads For Servo System

Compliant coupled loads, which are universal in applications, often lead to lowresponses or vibrations in speed and position control, thus lowering the performance of theservo system. As a result, control of the compliant coupled loads and vibration suppressionhave become an important problem for servo systems. Based on the two-mass model, thisthesis carried out studies towards vibrations within different frequency range. The majorcontents and achievements are as follows:For low frequency vibrations which are far below the crossover frequency of thespeed loop, the control structure based on IP speed regulator was adopted. Two new poleplace methods were proposed to expand the narrow load inertia ratio of the traditionalmethods. One of the proposed methods was based on the combination of real and complexpoles, and the other was based on expanded feedback structures, thus achieving effectivevibration suppression within a wide range of load ratio.For middle-frequency vibrations whose frequencies are higher, but still below thecrossover frequency, a disturbance observer was adopted to realize the extended feedbackstructure. Parameters of the controller were selected according to resonance ratio controlstructure and coefficient diagram method. The unfavorable effect cussed by undeaddisturbance observe was analyzed and the criterions for band width selection of theobserver was proposed, thus partially achieving vibration suppression within themiddle-frequency range.For middle-frequency resonances which are close with the crossover frequency of thespeed loop, suppression methods based on adaptive notch filter was adopted. The reasonfor the resonance frequency detection errors caused by high damping coefficient wasanalyzed with describing function method, and an approach for frequency correction wasproposed based on self-tuning low pass filter, which guaranteed the effectiveness of theadaptive notch filterFor vibrations with small load inertia ratio and little disturbance, the use of inputshaper was proposed for speed and position control of a servo system with compliantcoupled loads. Time optimal input shaper was selected as the most appropriate for fullydigital controlled servo systems. Parameter selection criterions of the Time optimal inputshaper were also studied, thus achieving vibration suppression for small inertia ratio.With the study of compliant coupled loads controls the main theme, this thesis performed a detailed survey of relevant research reports. The close-loop method wascombined with the open-loop method in providing an entire set of solutions for vibrationsuppression problems in the control of compliant coupled loads. Experiment resultsproved that the proposed set of solutions is capable of suppressing vibrations within widefrequency ranges and inertia ratio range.