Add trajectory planner python script

2026-09-16 01:49:06 +08:00 · 2018-08-06 00:38:49 -04:00
parent 126f089593
commit 26b87bb95b
1 changed files with 62 additions and 0 deletions
@@ -0,0 +1,62 @@
+import numpy as np
+import math
+
+def trapPlan(Xf, Xi, Vf, Vi, Af, Ai, Vmax, Amax, Dmax, dT=0.001):
+
+    s = np.sign(Xf - Xi)   # Sign 
+
+    Ar = s*Amax     # Maximum Acceleration (signed)
+    Dr = -s*Dmax    # Maximum Deceleration (signed)
+    Vr = s*Vmax     # Maximum Velocity (signed)
+
+    if(s*Vi > s*Vr):
+        Ar = -s*Amax
+    
+    Ta = (Vr - Vi)/Ar   # Acceleration Time
+    Td = (Vf - Vr)/Dr   # Deceleration Time
+
+    dX = Xf - Xi    # Distance to travel
+    if Vf == 0:
+        dXmin = Ta*(Vr + Vi)/2 + Td*(Vr)/2
+    elif np.sign(Vf) == np.sign(Vr):
+        dXmin = Ta*(Vr + Vi)/2 + Td*(Vr-Vf)/2 + Td*Vf
+    else:
+        dXmin = Ta*(Vr + Vi)/2 + Td*(Vr - s*Vf)/2
+
+    if s*dXmin > s*dX:
+        Vr = s*math.sqrt(-1*Ar*(Vf*Vf-2*Dr*dX))/math.sqrt(Dr-Ar)
+        Ta = max(0, (Vr - Vi)/Ar)
+        Tv = 0
+        Td = max(0, (Vf - Vr)/Dr)
+    else:
+        Tv = (dX - dXmin)/Vr
+    
+    t_traj = np.arange(0, Ta+Tv+Td, dT)
+    y = [None]*len(t_traj)
+    yd = [None]*len(t_traj)
+    ydd = [None]*len(t_traj)
+
+    for i in range(len(t_traj)):
+        t = t_traj[i]
+        if(t <= 0):
+            y[i] = Xi
+            yd[i] = Vi
+            ydd[i] = Ai
+        elif(t <= Ta):
+            y[i] = y[i-1] + yd[i-1] * dT + (0.5*ydd[i-1]*dT*dT)
+            yd[i] = yd[i-1] + ydd[i-1]*dT
+            ydd[i] = Ar
+        elif(t <= Ta+Tv):
+            y[i] = y[i-1] + yd[i-1] * dT
+            yd[i] = yd[i-1]
+            ydd[i] = 0
+        elif(t <= Ta+Tv+Td):
+            y[i] = y[i-1] + yd[i-1] * dT + (0.5*ydd[i-1]*dT*dT)
+            yd[i] = yd[i-1] + ydd[i-1]*dT
+            ydd[i] = Dr
+    
+    return (y, yd, ydd)
+
+
+(Y, Yd, Ydd) = trapPlan(10, 0, 0, 0, 0, 0, 10, 20, 20)
+print(Y[len(Y)-1])