Rolling digital surface measurement apparatus

A surface measuring apparatus comprising:

• a frame,
• a plurality of wheels supported on said frame in rolling contact with a surface to be measured, said plurality of wheels including a pair of longitudinally aligned wheels mounted on said frame in predetermined spaced relation,
• said plurality of wheels further including a floating wheel mounted on said frame midway between said pair of longitudinally aligned wheels and in contact with the surface to be measured with said floating wheel being capable of movement toward and away from said frame,
• a linear position transducer connected to said floating wheel to produce a signal corresponding to the movement of said floating wheel toward and away from said frame,
• an odometer mounted on said frame and connected to one of said pair of longitudinally aligned wheels for outputting a signal D directly proportional to a distance traveled by said one of said pair of longitudinally aligned wheels on the surface to be measured,
• a computer to receive said signal D from said odometer to trigger said computer to record intermittent regularly spaced readings of said linear position transducer every time said one of said pair of longitudinally aligned wheels travels a distance S between the center of said one of said pair of longitudinally aligned wheels and the center of said floating wheel,
• the following equations defining the relationship between point elevations on the surface to be measured which are designated by H.sub.0, H.sub.1 and H.sub.j, where j is the index of the measurement point currently under consideration, R.sub.i is the reading of said linear position transducer associated with a point i, and
• N is the index of the final measurement point:
• H.sub.0 =0
• and ##EQU19##