add bsplinepath sample

Author: AtsushiSakai

PathPlanning/BSplinePath/Figure_1.png

@@ -0,0 +1,56 @@
+"""
+
+Path Plannting with B-Spline
+
+author: Atsushi Sakai (@Atsushi_twi)
+
+"""
+
+import numpy as np
+import matplotlib.pyplot as plt
+import scipy.interpolate as si
+
+# parameter
+N = 3  # B Spline order
+
+
+def bspline_planning(x, y, sn):
+    t = range(len(x))
+    x_tup = si.splrep(t, x, k=N)
+    y_tup = si.splrep(t, y, k=N)
+
+    x_list = list(x_tup)
+    xl = x.tolist()
+    x_list[1] = xl + [0.0, 0.0, 0.0, 0.0]
+
+    y_list = list(y_tup)
+    yl = y.tolist()
+    y_list[1] = yl + [0.0, 0.0, 0.0, 0.0]
+
+    ipl_t = np.linspace(0.0, len(x) - 1, sn)
+    rx = si.splev(ipl_t, x_list)
+    ry = si.splev(ipl_t, y_list)
+
+    return rx, ry
+
+
+def main():
+    print(__file__ + " start!!")
+    # way points
+    x = np.array([-1.0, 3.0, 4.0, 2.0, 1.0])
+    y = np.array([0.0, -3.0, 1.0, 1.0, 3.0])
+    sn = 100  # sampling number
+
+    rx, ry = bspline_planning(x, y, sn)
+
+    # show results
+    plt.plot(x, y, '-og', label="Waypoints")
+    plt.plot(rx, ry, '-r', label="B-Spline path")
+    plt.grid(True)
+    plt.legend()
+    plt.axis("equal")
+    plt.show()
+
+
+if __name__ == '__main__':
+    main()