How to change the orientation of a robot

edit

Hello guys, i have a problem with my simulation. I wanna learn a robot to navigate via reinforcement learning and that the robot generalizes better i wanted the robot to have multiple start locations which get picked randomly

But i got the issue that even though my code sets the orientation yaw angle the robot always faces the same direction at each point

Here is the function i wrote to set the pose of the robot:

def reset_pose():

state_msg = ModelState()
state_msg.model_name = 'pepper_MP'

n_pose=range(4)

choice= random.choice(n_pose)

if choice == 0:
    x=0
    y=0
    z=3.14
if choice == 1:
    x=-7
    y=4
    z=-1
if choice == 2:
    x=1
    y=4
    z=3.7
if choice == 3:
    x=-7
    y=-4
    z=0.7

state_msg.pose.position.x = x
state_msg.pose.position.y = y
state_msg.pose.position.z = 0
state_msg.pose.orientation.x = 0
state_msg.pose.orientation.y = 0
state_msg.pose.orientation.z = z
state_msg.pose.orientation.w = 0


rospy.wait_for_service('/gazebo/set_model_state')
try:
    set_state = rospy.ServiceProxy('/gazebo/set_model_state', SetModelState)
    resp = set_state( state_msg )
    return x,y
except rospy.ServiceException:
    print ("Service call failed: %s")

The x and y coordinate get set correct but the state_msg.pose.orientation doesnt get set correctly