diff --git a/remote_control/casadi_opt.py b/remote_control/casadi_opt.py
index c20167b..bdf5f50 100644
--- a/remote_control/casadi_opt.py
+++ b/remote_control/casadi_opt.py
@@ -236,8 +236,9 @@ class OpenLoopSolver:
         for o in obstacles:
             p = obstacles[o].pos
             r = obstacles[o].radius
-            for k in range(1,self.N):
-                self.opti.subject_to((self.X[0,k]-p[0])**2 + (self.X[1,k]-p[1])**2 + self.slack  > r**2)
+            if p is not None:
+                for k in range(1,self.N):
+                    self.opti.subject_to((self.X[0,k]-p[0])**2 + (self.X[1,k]-p[1])**2 + self.slack > r**2)
         #    pass
         posx = self.X[0, :]
         posy = self.X[1, :]