disturbance observer

Disturbance observer

Rejecting Fast Narrow-Band Disturbances With Slow Sensor Feedback for Quality Beam Steering in Selective Laser Sintering

A fundamental problem arises in feedback control when the system is subject to fast disturbances but can only get slowly updated sensor feedback. The problem is particularly challenging when the disturbances have frequency components near or beyond …

A Tutorial on Loop-shaping Control Methodologies for Precision Positioning Systems

An Inverse-Free Disturbance Observer for Adaptive Narrow-Band Disturbance Rejection With Application to Selective Laser Sintering

Selective laser sintering (SLS) is an additive manufactur- ing (AM) process that builds 3-dimensional (3D) parts by scan- ning a laser beam over powder materials in a layerwise fashion. Due to its capability of processing a broad range of materials, …

Multi-band beyond-Nyquist Disturbance Rejection on a Galvanometer Scanner System

Multirate Forward-model Disturbance Observer for Feedback Regulation beyond Nyquist Frequency

Overview and New Results in Disturbance Observer based Adaptive Vibration Rejection with Application to Advanced Manufacturing

Vibrations with unknown and/or time-varying frequencies significantly affect the achievable performance of control systems, particularly in precision engineering and manufacturing applications. This paper provides an overview of …

Adaptive Suppression of High-Frequency Wide-Spectrum Vibrations With Application to Disk Drive Systems

New Repetitive Control with Improved Steady-State Performance and Accelerated Transient

In repetitive control (RC), the enhanced servo performance at the fundamental frequency and its higher order harmonics is usually followed by undesired error amplifications at other frequencies. In this paper, we discuss a new structural …

Methods for Closed-loop Compensation of Ultra-high Frequency Disturbances in Hard Disk Drives and Hard Disk Drives Utilizing Same

The importance of safe and flexible disturbance rejection at high frequencies has been ever increasing in modem control systems. For example, new applications of hard disk drives (HDD) require that the HDD control system be robust to (e.g., have the …