Basic consideration of vibration suppression and disturbance rejection control of multi-inertia system using SFLAC (state feedback and load acceleration control)

High-Performance Control of Dual-Inertia Servo-Drive Systems Using Low-Cost Integrated SAW Torque Transducers

“…Until recently, therefore, difficulties in acquiring reliable low-cost noninvasive shaft torque transducers have precluded their use in all but a minority of specialist closed-loop servo-drive systems, and recourse to observer-based state-estimation techniques has consequently been commonplace [4]- [6], [12]. In a simulation environment, state-variable controllers [13] are readily shown to provide enhanced control performance, with the observer bandwidth being assigned to be much higher than the system dynamics and all the states being assumed delay free and noise free. However, in practical high-performance servo-drive systems employing a single quantized feedback sensor, highbandwidth observers impart problematic noise-amplifying attributes (similar to the PID controller): stability problems arise primarily due to finite resolution of sensors and unmodeled resonant modes.…”

“…1(a) provides a schematic of a two-inertia representation of a servo-drive system, where the motor angular velocity is denoted as ω m and the load velocity is denoted as ω d . Since damping losses are usually considered to be relatively low, they are neglected without significantly affecting the accuracy of the forgoing analysis [1], [2], [4]- [6], [9], [10] [12], [13]. Fig.…”

Speed acquisition methods for high-bandwidth servo drives

“…To damp mechanical resonance in a servo drive chain, the feedback of acceleration or torque from different points in the resonant system has been proposed [33], as well as feedback of speed differences between the inertias [38,37]. Those methods are steps towards a state control; the model of the resonant system has to be known, an observer needs to be designed, and the feedback is designed to stabilize the model's poles.…”

“…Nearly all publications on this subject are limited to two-inertia models, pointing out that higher order systems can be approximated this way [33]. The frequencies to be actively damped are usually significantly lower than the lowest resonance of the setup investigated here, which is 970 Hz.…”

“…Where observers for multi inertia systems are used, they are often designed by placing all poles to one location in the s-plane [33] or as a Kalman filter [34]. [35] uses the poles of the state control loop, left-shifted by a constant distance.…”