Added a new file with a function for the PID controller

PIDFunction.py

@@ -0,0 +1,108 @@
+import pybullet as p
+import math
+import time
+import pybullet_data
+import math
+import matplotlib.pyplot as plt
+import numpy as np
+physicsClient = p.connect(p.GUI)#or p.DIRECT for non-graphical version 
+
+p.setAdditionalSearchPath(pybullet_data.getDataPath()) #optionally
+p.setGravity(0,0,-10)
+planeId = p.loadURDF("plane.urdf")
+startPos = [0,0,0]
+startOrientation = p.getQuaternionFromEuler([0,0,0])
+robotId = p.loadURDF("olympian.urdf",startPos, startOrientation, 
+                   # useMaximalCoordinates=1, ## New feature in Pybullet
+                   flags=p.URDF_USE_INERTIA_FROM_FILE)
+
+xValues = np.linspace(0, 20, 200)
+yValues = [math.sin(i) for i in xValues]
+yValues = [i * 0.2 for i in yValues]
+plt.plot(xValues, yValues)
+plt.show()
+print(yValues)
+
+def calcCOM():
+    
+    #CALCULATE COM
+    masstimesxpossum = 0.0
+    masstimesypossum = 0.0
+    masstimeszpossum = 0.0
+    masssum = 0.0
+    for i in range(0, p.getNumJoints(robotId) -1):
+        
+        # if(i >= 0):
+        #     print(p.getJointInfo(robotId, i)[0:13])
+        
+        wheight = p.getDynamicsInfo(robotId, i)[0]
+        xpos = p.getLinkState(robotId, i)[0][0]
+        ypos = p.getLinkState(robotId, i)[0][1]
+        zpos = p.getLinkState(robotId, i)[0][2]
+        
+        masstimesxpossum += (wheight * xpos)
+        masstimesypossum += (wheight * ypos)
+        masstimeszpossum += (wheight * zpos)
+        masssum += wheight
+        
+        # print(wheight)
+        # print(xpos)
+        # print(ypos)
+        # print(zpos)
+        # print("\n")
+        p.stepSimulation()
+    com = (masstimesxpossum/masssum, masstimesypossum/masssum, masstimeszpossum/masssum)
+    
+    return com
+
+def footError():
+    robotCOM = calcCOM()
+    realRobotCOM = robotCOM[1]
+    footCOM = p.getLinkState(robotId, 15)
+    realFootCOM = footCOM[0][1]
+    error = realRobotCOM - realFootCOM
+    print(realFootCOM, realRobotCOM)
+    return error
+
+def error(targetValue):
+    robotCOM = calcCOM()
+    realRobotCOM = robotCOM[1]
+    error = realRobotCOM - targetValue
+    print(targetValue, realRobotCOM, error)
+    return error
+
+Array = [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]
+positions = [0]*23
+forces = [1000]*23
+indexes = list(range(0,23))
+
+# p.setJointMotorControl2(robotId, 20, p.POSITION_CONTROL, targetPosition = 0, force = 10000)
+# p.setJointMotorControl2(robotId, 14, p.POSITION_CONTROL, targetPosition = 0, force = 10000)
+doneYs = []
+initial_error = 50
+
+ka = 0
+
+def PIDsinCurve(i):
+    
+    doneYs.append(i)
+    # print(doneYs)
+    treshold = 0.01
+    initial_error = 50
+    while(abs(initial_error) > treshold):
+        print("Inside the loop, current y value is " + str(i))
+        Kc = -0.5
+        bias = 0
+        initial_error = error(i)
+        global ka
+        ka += Kc*initial_error + bias
+        print("error" + str(initial_error))
+        positions[21] = ka
+        positions[15] = ka
+        positions[18] = ka
+        positions[12] = ka
+        p.setJointMotorControlArray(robotId, indexes, p.POSITION_CONTROL, targetPositions = positions, forces = forces)
+        p.stepSimulation()
+    
+for i in yValues:
+    PIDsinCurve(i)

PIDsinCurve.py

@@ -1,8 +1,10 @@
 import pybullet as p
+import math
 import time
 import pybullet_data
 import math
 import matplotlib.pyplot as plt
+import numpy as np
 physicsClient = p.connect(p.GUI)#or p.DIRECT for non-graphical version 
 
 p.setAdditionalSearchPath(pybullet_data.getDataPath()) #optionally
@@ -14,6 +16,12 @@ robotId = p.loadURDF("olympian.urdf",startPos, startOrientation,
                    # useMaximalCoordinates=1, ## New feature in Pybullet
                    flags=p.URDF_USE_INERTIA_FROM_FILE)
 
+xValues = np.linspace(0, 20, 200)
+yValues = [math.sin(i) for i in xValues]
+yValues = [i * 0.2 for i in yValues]
+plt.plot(xValues, yValues)
+plt.show()
+print(yValues)
 
 def calcCOM():
     
@@ -45,10 +53,9 @@ def calcCOM():
         p.stepSimulation()
     com = (masstimesxpossum/masssum, masstimesypossum/masssum, masstimeszpossum/masssum)
     
-
     return com
 
-def error():
+def footError():
     robotCOM = calcCOM()
     realRobotCOM = robotCOM[1]
     footCOM = p.getLinkState(robotId, 15)
@@ -57,22 +64,38 @@ def error():
     print(realFootCOM, realRobotCOM)
     return error
 
+def error(targetValue):
+    robotCOM = calcCOM()
+    realRobotCOM = robotCOM[1]
+    error = realRobotCOM - targetValue
+    print(targetValue, realRobotCOM, error)
+    return error
+
+ka = 0
 Array = [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]
 positions = [0]*23
 forces = [1000]*23
 indexes = list(range(0,23))
-ka = 0
+
 # p.setJointMotorControl2(robotId, 20, p.POSITION_CONTROL, targetPosition = 0, force = 10000)
 # p.setJointMotorControl2(robotId, 14, p.POSITION_CONTROL, targetPosition = 0, force = 10000)
+doneYs = []
+initial_error = 50
 
-while(True):
-    Kc = -0.05
-    bias = 0
-    initial_error = error()
-    ka += Kc*initial_error + bias
-    print(initial_error)
-    positions[21] = ka
-    positions[15] = ka
-    positions[18] = ka
-    positions[12] = ka
-    p.setJointMotorControlArray(robotId, indexes, p.POSITION_CONTROL, targetPositions = positions, forces = forces)
+for i in yValues:
+    doneYs.append(i)
+    # print(doneYs)
+    treshold = 0.01
+    initial_error = 50
+    while(abs(initial_error) > treshold):
+        print("Inside the loop, current y value is " + str(i))
+        Kc = -0.5
+        bias = 0
+        initial_error = error(i)
+        ka += Kc*initial_error + bias
+        print("error" + str(initial_error))
+        positions[21] = ka
+        positions[15] = ka
+        positions[18] = ka
+        positions[12] = ka
+        p.setJointMotorControlArray(robotId, indexes, p.POSITION_CONTROL, targetPositions = positions, forces = forces)