Efficiency and control performance of man in followins stochastic signals

Abstract

Human operator tracking performance was investigated experimentally as a function of the forcing function bandwidth and the number of simultaneous tracking tasks. Section 2 describes the experimental setup and procedures. In Section 3 an introduction to the quasilinear description of manual control is given (performance criteria, describing function of the human operator, transinformation rate). In Section 4 the results of an investigation of the effect of man-machine interface parameters on the manual control loop are summarized. In Sections 5 and 6 the results of experiments on the dependence of manual tracking on the input information rate (given by the forcing function bandwidth and the number of simultaneous tasks) are given. The investigations showed that manual control is only useful for forcing functions of a bandwidth less than 1 Hz. For signals within this frequency region the human operator is highly adaptive to the forcing function bandwidth. The adaptability of the human operator can be understood as a minimization of the mean squared control error within the restraints of closed loop stability. For the single tracking task a maximal transinformation rate of 6---8 bit/sec was measured. The results of the multidimensional tracking tasks showed that the human operator is able to perform up to four tasks simultaneously with only little degradation of his tracking performance. Thereby the transmitted information rate increases almost linearly with the number of simultaneous tasks. This shows the high capability of the human operator for parallel information transmission and implies a limitation of manual control by the manual output process.