Real‐time compensation for positioning performance using on‐line parameter identification and initial value compensation

Abstract

SUMMARYVariations and/or uncertainties in environments of mechatronic systems, such as electrical/mechanical parameter changes and nonlinear components, generally deteriorate the motion control performance. In our research, the fast and precise position settling performance for parameter variations in positioning devices can be improved by techniques of an on-line parameter identification and an initial value compensation. The proposed technique allows the positioning systems to be adaptive and robust for unknown parameter variations. The effectiveness of the approach has been verified by numerical simulations and experiments using a prototype.

Improvement of Settling Performance by Mode-Switching Control With Split Initial-Value Compensation Based on Input Shaper

“…Configuration of Prototype Fig. 1 shows a configuration of a positioning device for galvanoscanners in laser manufacturing machines, as a laboratory experimental setup [10], [12]. The galvanoscanner is composed of a servomotor with a galvanomirror, where the motor angle can be directly detected and controlled.…”

“…The thin line (gain perturbation) indicates that the position cannot follow the dotted nominal response r (nominal) due to the gain perturbation, resulting in the deterioration in the settling performance. The authors have already proposed an IVC approach in the framework of the mode-switching control in [12], which acted in the following two modes.…”

“…The mode-switching control with the initial-value compensation (IVC) is one of the promising approaches to improve the positioning performance against the perturbations until the settling, by giving additional control input as the IVC at the mode-switching timing [7]- [11]. The authors have already proposed a mode-switching-control scheme using an IVC [12], where parameter variations of the plant were identified during the acceleration, and then, response variations were estimated as initial values of the plant. During the deceleration, following the estimations, compensation for the parameter variations and the IVC for the initial values were applied to improve the deterioration in the settling performance.…”

High‐precision positioning with strain feedback using piezoelectric element

“…With these requirements in mind, the authors designed the following feedback compensator composed of phase lead-lag compensation and two notch filters [5]: With these requirements in mind, the authors designed the following feedback compensator composed of phase lead-lag compensation and two notch filters [5]:…”

“…Existing control schemes proposed for compensation for the above-mentioned vibration modes include gain compensation using notch filters and other elements based on the small-gain theorem, and phase compensation using phase-stable design with vector loci at resonance frequencies set on the Nyquist right half-plane [4,5]. However, notch filters used for gain compensation reduce gain only in a limited frequency range, and are not robust to variations of the resonant frequency.…”