Human frequency characteristics in manual tracking of three input waves

Abstract

The experimental task was manual tracking. The parameters studied were input wave forms. The wave forms used were a step wave, a sinusoidal wave, and a random wave. Human responses to a step wave are typically described in a time domain as O_a (t). But they can also be described in a frequency domain as G ₁(jω) by Fourier transform:

Human responses to sinusoidal waves of various frequencies with their amplitude held constant are described in a frequency domain as G ₂(jω). Responses to a random wave consisting of superposed and filtered sinusoidal waves are similarly described in a frequency domain as G ₃(jω). Frequency characteristics of human responses to the three input waves were similar in shape, but somewhat reflected the characteristics of each input. From these frequency characteristics, called closed-loop characteristics and referred to as G(jω), open-loop characteristics of H(jω) may be calculated by the following equation:

In classical control theories it is conventional to evaluate a system on the basis of the three indices of rapidity, stability and control performance, human responses to the three input waves as observed in the laboratory will be discussed in terms of three indices.

Keywords:

• Manual tracking
• Control theory
• Transfer function