The Impact of Reference-Command Preview on Human-in-the-Loop Control Behavior

TL;DR

This study investigates how previewing reference commands affects human control behavior, showing that limited preview improves performance by aiding delay compensation, while excessive preview can impair phase lead utilization.

Contribution

It provides experimental evidence on the effects of different preview lengths on human-in-the-loop control performance and control modeling.

Findings

Preview improves control performance by aiding delay compensation.

Excessive preview can reduce control effectiveness.

Control models reveal changes in behavior with different preview lengths.

Abstract

This article presents results from an experiment in which 44 human subjects interact with a dynamic system to perform 40 trials of a command-following task. The reference command is unpredictable and different on each trial, but all subjects have the same sequence of reference commands for the 40 trials. The subjects are divided into 4 groups of 11 subjects. One group performs the command-following task without preview of the reference command, and the other 3 groups are given preview of the reference command for different time lengths into the future (0.5 s, 1 s, 1.5 s). A subsystem identification algorithm is used to obtain best-fit models of each subject's control behavior on each trial. The time- and frequency-domain performance, as well as the identified models of the control behavior for the 4 groups are examined to investigate the effects of reference-command preview. The results suggest that preview tends to improve performance by allowing the subjects to compensate for sensory time delay and approximate the inverse dynamics in feedforward. However, too much preview may decrease performance by degrading the ability to use the correct phase lead in feedforward.