Effectiveness of Basic Display Augmentation in Vehicular Control by Visual Field Cues

The effectiveness of different basic display augmentation concepts (fixed reticle, velocity vector, and predicted future vehicle path) for remotely piloted vehicles (RPV) controlled by a vehicle mounted television camera is investigated. The task is lateral manual control of a low flying RPV along a straight reference line in the presence of random side gusts. The man-machine system and the visual interface are modeled as a linear time-invariant system. Minimization of a quadratic performance criterion is assumed to underly the control strategy of a well-trained human operator. The solution for the optimal feedback matrix enables the explicit computation of the variances of lateral deviation and directional error of the vehicle and of the control force that are used as performance measures. These variances are initially calculated with assumed values of human operator parameters such as weighting coefficients and noise levels. In particular, it is investigated whether and to what extent the human operator actually utilizes the display of information representing higher order state components such as lateral velocity and acceleration. The results show that the effectiveness of the display aids strongly depends on the vehicle dynamics and the spectrum of the disturbance. A velocity vector reticle is very effective for fast vehicle dynamics and rather ineffective for slow vehicle dynamics. On the other hand, a future vehicle path reticle is very effective for slow vehicle dynamics but less effective for fast vehicle dynamics and fast disturbances. The analytical results obtained are then validated by means of a specially developed flight simulator.