Control systems approach to a ski-turn analysis.

Abstract Ski-turn mechanics are explained in terms of a simple structural scheme with negative feedback organization. The skier's body is depicted as an inverted pendulum whose movement is controlled by force applied at a supporting point. The control force results from the skis' slide-slip, and may be amplified by their edging. Turn control is accomplished by controlling the body bank angle. Simple linear theory is used to explain the main features of the model. Investigations of the model, using an analogue computer, showed that it remained fully adequate for single turn as well as for rhythmical turn sequences. Special attention has been paid to the process of turn inititiation. Modern “avalement” technique is interpreted in terms of a model. Finally, the model is discussed and supported from a human engineering point of view.