This is just a trigonometry problem of converting from the path coordinates to cartesian coordinates.
I would start by converting each point to a relative rectangular vector. What you have sounds like the arclength and radius of a set of arcs, right? An arc can be described by its length s, radius r, and angle theta by s=r*theta. rearrange and solve for theta: theta = s/r.
now you can use basic trig to get the lateral and tangential distance (I'll call them Ll and Lt) from one point to the next. The tangential distance is found from sin(theta) = Ll / r, and the lateral is cos(theta)= (r-Lt)/r.
solve that all out and Ll= r*sin(s/r) and Lt=r(1-cos(s/r)). It should be easy to do this in labview.
Keep track of that theta value though, because once we move on to the next point, the local coordinates (I told you they were relative!) have rotated by theta. The sum of all the angles since some starting point is the total angular displacement, let's call it alpha.
translate one vector into rectangular coordinates relative to the first point it by a transform through alpha:
Lx = [Lt*sin(alpha)+Ln*cos(alpha)] , Ly = [Lt*cos(alpha) + Ln*sin(alpha)]. at this point we still are just talking about the point-to-point change in distance, add them all up to get X,Y coordinates for the graph.
-Barrett
CLD
