PSYCHOLOGICAL AND PHYSIOLOGICAL ASPECTS OF CONTROL MECHANISMS WITH SPECIAL REFERENCE TO TANK GUNNERY. PART I

It appears that joy-sticks which are to be used under bumpy or jolting conditions should have a frictional resistance of about 2 lb to ensure greatest precision of movement, and handles for use in direct laying systems should have gear ratios.

Abstract

Accuracy of laying guns, predictors, etc., may be limited by physiological and psychological as well as by mechanical factors, e.g. by the suitability or unsuitability of the positions of the controls, the amplitude of their movements, the velocity with which they are to be operated, their stiffness, the vibration to which the operator may be subject, the radii of hand-wheels, the gear ratios used, and so forth. The effects of these variables have been given a preliminary investigation and various general rules and relations derived which might be of assistance to designers, or might justify experimental trial of promising frictions, gear ratios, etc., in actual equipment. Thus, for instance, it appears that joy-sticks which are to be used under bumpy or jolting conditions should have a frictional resistance of about 2 lb to ensure greatest precision of movement. Again, handles for use in direct laying systems should have gear ratios Such that the hand is winding fast (100 to 200 r.p.m.) when laying on the fastest targets which are likely to be encountered. provided this does not interfere with accurate observation in sighting telescope, since the angular accuracy of laying on a target of given angular velocity is greatest when the hand is winding fast. A radius of 3 to 4 inches is suitable for most purposes; it gives a combination of a high maximum winding rate and reasonable work-output.