# A Smith Predictor Modified with a Pseudo Feedforward Control for the Charge-Coupled Device-Based Optoelectronic Tracking System

## TL;DR

This paper improves tracking accuracy in a high-precision optoelectronic system by modifying the Smith predictor with pseudo feedforward control.

## Contribution

A modified Smith predictor with pseudo feedforward control is proposed to enhance tracking performance in optoelectronic systems.

## Key findings

- The modified method reduces maximum residual error at 1 Hz by 22.5% compared to the classic Smith predictor.
- Across the main frequency band (0.2 Hz to 2 Hz), the proposed method consistently lowers residual errors.

## Abstract

In the high-precision optoelectronic tracking system (OTS) based on a charge-coupled device (CCD), the boresight error extracted from the tracking image contains an undeniable delay, which directly limits the control bandwidth of visual tracking. High bandwidth means high response speed and tracking accuracy. Generally, a model-based delay compensation control method called the Smith predictor is utilized to separate time delay from the closed loop to promote the control bandwidth. However, due to the existence of errors between the established model and the real object, the improvement in the bandwidth is still limited to ensure system stability, resulting in insufficient tracking performance. In this paper, to solve the problem, a Smith predictor modified with pseudo feedforward control for the OTS is proposed. The experimental results demonstrate that the proposed method achieves significant improvements in tracking performance, reducing the maximum residual error at 1 Hz from 365 arcseconds (using the classic Smith predictor) to 283 arcseconds, a 22.5% improvement. Across the main frequency band (0.2 Hz to 2 Hz), the residual errors were consistently lower using the proposed method.