Tactile Information Processing by Human Operators in Control Systems

The response of human operators in control systems to electrocutaneous stimulation inputs was investigated. Human subjects were asked to track two-dimensional tactile inputs (applied at the waist) by means of force applied to a two-axis isometric control stick. Stimulation and force signals recorded from the experiment were used to obtain mathematical models of the subjects´ input-output characteristics. Coherence analysis showed that the operators´ behavior could be represented by linear models in the frequency range of 0 to 0.8 rad/s and that cross-coupling between the two axes is negligible. The implications of the results in the design of artificial kinesthetic feedback systems to aid in the rehabilitation of traumatic paraplegics are discussed.