MATLAB: Changing a parameter in a differential equation according to a condition

differential equationseventsmodelodeode45

I am trying to change the input wheel velocities of a mobile robot according to a position condition ?
if d > 0 & d < 0.4
        p.WR = 0.51;
        p.WL = 0.5;
    elseif d > 0.4 & d < 0.8 
        p.WR = 0.5;
        p.WL = 0.51;
    elseif d == 0.4
        p.WR = 0.5;
        p.WL = 0.5;
    end 
function dt = mydglw9(t,c,p)
     x = c(1);y = c(2);th = c(3);
      dx = (((p.r*p.WL)+(p.r*p.WR))/2) * cos(th);
      dy = (((p.r*p.WL)+(p.r*p.WR))/2) * sin(th);
      dth= ((p.r*p.WL)-(p.r*p.WR))/p.L;
      dt = [dx;dy;dth];
      pose = [x y th];
  end
however i always get the error [ Reference to non-existent field 'WL' ], is there a way to make the solver check the condition before solving the differential equations ?

Best Answer

What values does ‘d’* have?
Note that in this if block, if ‘d<=0’ or ‘d>=0.8’, the if block will not execute and the values within it will not be assigned.
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