diff --git a/.gitmodules b/.gitmodules
index a5d40c89..e69de29b 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,12 +0,0 @@
-[submodule "PathTracking/rear_wheel_feedback/pycubicspline"]
-	path = PathTracking/rear_wheel_feedback/pycubicspline
-	url = https://github.com/AtsushiSakai/pycubicspline.git
-[submodule "PathTracking/stanley_controller/pycubicspline"]
-	path = PathTracking/stanley_controller/pycubicspline
-	url = https://github.com/AtsushiSakai/pycubicspline
-[submodule "PathTracking/lqr_speed_steer_control/pycubicspline"]
-	path = PathTracking/lqr_speed_steer_control/pycubicspline
-	url = https://github.com/AtsushiSakai/pycubicspline
-[submodule "PathTracking/model_predictive_speed_and_steer_control/pycubicspline"]
-	path = PathTracking/model_predictive_speed_and_steer_control/pycubicspline
-	url = https://github.com/AtsushiSakai/pycubicspline
diff --git a/PathTracking/lqr_speed_steer_control/pycubicspline b/PathTracking/lqr_speed_steer_control/pycubicspline
deleted file mode 160000
index 34b741f7..00000000
--- a/PathTracking/lqr_speed_steer_control/pycubicspline
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit 34b741f7eee6cfbe851317ca36dab59fc560ba9a
diff --git a/PathTracking/model_predictive_speed_and_steer_control/model_predictive_speed_and_steer_control.py b/PathTracking/model_predictive_speed_and_steer_control/model_predictive_speed_and_steer_control.py
index f1fe6ae2..0028c0a8 100644
--- a/PathTracking/model_predictive_speed_and_steer_control/model_predictive_speed_and_steer_control.py
+++ b/PathTracking/model_predictive_speed_and_steer_control/model_predictive_speed_and_steer_control.py
@@ -5,12 +5,14 @@ Path tracking simulation with iterative linear model predictive control for spee
 author: Atsushi Sakai (@Atsushi_twi)
 
 """
+import sys
+sys.path.append("../../PathPlanning/CubicSpline/")
 
 import numpy as np
 import math
 import cvxpy
 import matplotlib.pyplot as plt
-from pycubicspline import pycubicspline
+import cubic_spline_planner
 
 NX = 4  # x = x, y, v, yaw
 NU = 2  # a = [accel, steer]
@@ -482,7 +484,8 @@ def smooth_yaw(yaw):
 def get_forward_course(dl):
     ax = [0.0, 60.0, 125.0, 50.0, 75.0, 30.0, -10.0]
     ay = [0.0, 0.0, 50.0, 65.0, 30.0, 50.0, -20.0]
-    cx, cy, cyaw, ck, s = pycubicspline.calc_spline_course(ax, ay, ds=dl)
+    cx, cy, cyaw, ck, s = cubic_spline_planner.calc_spline_course(
+        ax, ay, ds=dl)
 
     return cx, cy, cyaw, ck
 
@@ -490,10 +493,12 @@ def get_forward_course(dl):
 def get_switch_back_course(dl):
     ax = [0.0, 30.0, 6.0, 20.0, 35.0]
     ay = [0.0, 0.0, 20.0, 35.0, 20.0]
-    cx, cy, cyaw, ck, s = pycubicspline.calc_spline_course(ax, ay, ds=dl)
+    cx, cy, cyaw, ck, s = cubic_spline_planner.calc_spline_course(
+        ax, ay, ds=dl)
     ax = [35.0, 10.0, 0.0, 0.0]
     ay = [20.0, 30.0, 5.0, 0.0]
-    cx2, cy2, cyaw2, ck2, s2 = pycubicspline.calc_spline_course(ax, ay, ds=dl)
+    cx2, cy2, cyaw2, ck2, s2 = cubic_spline_planner.calc_spline_course(
+        ax, ay, ds=dl)
     cyaw2 = [i - math.pi for i in cyaw2]
     cx.extend(cx2)
     cy.extend(cy2)
diff --git a/PathTracking/model_predictive_speed_and_steer_control/pycubicspline b/PathTracking/model_predictive_speed_and_steer_control/pycubicspline
deleted file mode 160000
index 34b741f7..00000000
--- a/PathTracking/model_predictive_speed_and_steer_control/pycubicspline
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit 34b741f7eee6cfbe851317ca36dab59fc560ba9a
diff --git a/PathTracking/rear_wheel_feedback/rear_wheel_feedback.py b/PathTracking/rear_wheel_feedback/rear_wheel_feedback.py
index 7c66dc6f..486deb6c 100644
--- a/PathTracking/rear_wheel_feedback/rear_wheel_feedback.py
+++ b/PathTracking/rear_wheel_feedback/rear_wheel_feedback.py
@@ -5,9 +5,13 @@ Path tracking simulation with rear wheel feedback steering control and PID speed
 author: Atsushi Sakai(@Atsushi_twi)
 
 """
+import sys
+sys.path.append("../../PathPlanning/CubicSpline/")
+
 import math
 import matplotlib.pyplot as plt
-from pycubicspline import pycubicspline
+import cubic_spline_planner
+
 
 Kp = 1.0  # speed propotional gain
 # steering control parameter
@@ -188,7 +192,8 @@ def main():
     ay = [0.0, 0.0, 5.0, 6.5, 3.0, 5.0, -2.0]
     goal = [ax[-1], ay[-1]]
 
-    cx, cy, cyaw, ck, s = pycubicspline.calc_spline_course(ax, ay, ds=0.1)
+    cx, cy, cyaw, ck, s = cubic_spline_planner.calc_spline_course(
+        ax, ay, ds=0.1)
     target_speed = 10.0 / 3.6
 
     sp = calc_speed_profile(cx, cy, cyaw, target_speed)
diff --git a/PathTracking/stanley_controller/stanley_controller.py b/PathTracking/stanley_controller/stanley_controller.py
index 0bc8504f..f287bef4 100644
--- a/PathTracking/stanley_controller/stanley_controller.py
+++ b/PathTracking/stanley_controller/stanley_controller.py
@@ -5,10 +5,12 @@ Path tracking simulation with Stanley steering control and PID speed control.
 author: Atsushi Sakai (@Atsushi_twi)
 
 """
+import sys
+sys.path.append("../../PathPlanning/CubicSpline/")
+
 import math
 import matplotlib.pyplot as plt
-
-from pycubicspline import pycubicspline
+import cubic_spline_planner
 
 
 k = 0.5  # control gain
@@ -100,7 +102,8 @@ def main():
     ax = [0.0, 100.0, 100.0, 50.0, 60.0]
     ay = [0.0, 0.0, -30.0, -20.0, 0.0]
 
-    cx, cy, cyaw, ck, s = pycubicspline.calc_spline_course(ax, ay, ds=0.1)
+    cx, cy, cyaw, ck, s = cubic_spline_planner.calc_spline_course(
+        ax, ay, ds=0.1)
 
     target_speed = 30.0 / 3.6  # [m/s]