Piecewise system identification and trajectory acceleration reallocating for diamond turning of microlens arrays

Abstract

The use of microlens arrays (MLAs) manufactured through slow tool servo (STS) machining is becoming increasingly common in the field of complex surface optics. However, the current STS technique presents a significant challenge in balancing machining efficiency and surface profile accuracy, mainly due to the rapid variations in the spatial frequency of the microlenses. To address this challenge, this study proposes a piecewise system identification method along with trajectory acceleration reallocating. Specifically, the proposed method models the machine lathe Z-axis as a dynamic system piecewise, segmented by different trajectory acceleration intervals, to accurately approximate the nonlinear dynamic response of Z-axis. Tracking error prediction and trajectory acceleration reallocating are developed based on the piecewise system identification. To validate the proposed approach, diamond turning experiments were conducted on an ultraprecision machine lathe. The proposed approach significantly enhances the surface form accuracy while marginally improving the machining efficiency.