What we are going to learn

  • Learn the basics of how to use MoveIt! to move the end effectors of both arms of the PR2 robot simulation in Gazebo.

List of resources used in this post

Launching the simulation

When you click in the ROSject link, you will get a copy of the ROSject. You can then download it if you want to use it on our local computer, or you can just click Open to have it opened in ROSDS.

Once you have it open, you launch the simulation through the Simulation -> Select a launch file button. Then, in the pr2_description package select the pick_place_project_mod.launch launch file.

pr2_description pick_and_place_project_mod.launch in ROSDS

pr2_description pick_and_place_project_mod.launch in ROSDS

The following simulation should appear in your screen after a few seconds:

pr2 robot up and running in ROSDS

pr2 robot up and running in ROSDS

Launch a Moveit Arms test

Now that the simulation is running, you can run the demo that moves the arms of the robot using MoveIt!. For that, you can open a web shell (Tools->shell) and then type the following command:

$ rosrun pr2_description pr2_movit_demo.py
pr2_moving arms in ROSDS

pr2_moving arms in ROSDS

That file used to move the arms is on pr2/pr2_description/demos/pr2_moveit_demo.py and it has the following content:

#!/usr/bin/env python
# TODO: This is in construction based on the pr2 moveit
import rospy
import sys
import moveit_commander
import moveit_msgs.msg
import geometry_msgs.msg
import trajectory_msgs.msg

import copy
import actionlib
import rospy

from math import sin, cos
from moveit_python import (MoveGroupInterface,
                           PlanningSceneInterface,
                           PickPlaceInterface)
from moveit_python.geometry import rotate_pose_msg_by_euler_angles

from control_msgs.msg import FollowJointTrajectoryAction, FollowJointTrajectoryGoal
from control_msgs.msg import PointHeadAction, PointHeadGoal
from control_msgs.msg import GripperCommandAction, GripperCommandGoal
from move_base_msgs.msg import MoveBaseAction, MoveBaseGoal
from trajectory_msgs.msg import JointTrajectory, JointTrajectoryPoint

from pr2_description.srv import Pr2Move, Pr2MoveResponse, Pr2MoveRequest

from geometry_msgs.msg import Pose

class MovePR2(object):
    
    def __init__(self):
        
        
        rospy.loginfo("In Move PR2 Class init...")
        
        pr2_move_service = rospy.Service('/pr2_move_service', Pr2Move , self.move_callback)
        
        # MOVEIT
        moveit_commander.roscpp_initialize(sys.argv)
        rospy.logdebug("moveit_commander initialised...")
        
        rospy.logdebug("Starting Robot Commander...")
        self.robot = moveit_commander.RobotCommander()
        rospy.logdebug("Starting Robot Commander...DONE")
        
        self.scene = moveit_commander.PlanningSceneInterface()  
        rospy.logdebug("PlanningSceneInterface initialised...DONE")
        
        
        """
        MoveIt Groups For now:
        right_arm
        left_arm
        right_gripper
        left_gripper
        """
        self.moveit_groups_dict = {}
        
        
        self.group_right_arm = moveit_commander.MoveGroupCommander("right_arm")
        rospy.logdebug("MoveGroupCommander for right_arm initialised...DONE")
        # TODO: Add support for these new groups
        self.group_left_arm = moveit_commander.MoveGroupCommander("left_arm")
        rospy.logdebug("MoveGroupCommander for left_arm initialised...DONE")
        self.group_right_gripper = moveit_commander.MoveGroupCommander("right_gripper")
        rospy.logdebug("MoveGroupCommander for right_gripper initialised...DONE")
        self.group_left_gripper = moveit_commander.MoveGroupCommander("left_gripper")
        rospy.logdebug("MoveGroupCommander for left_gripper initialised...DONE")
        
        # Fill in The dictionary
        
        self.moveit_groups_dict = {"right_arm": self.group_right_arm,
                                   "left_arm":  self.group_left_arm,
                                   "right_gripper": self.group_right_gripper,
                                   "left_gripper": self.group_left_gripper
                                    }
        
        
        
        rospy.loginfo("PR2 ready to move!")

    def move_callback(self, request):
        
        move_response = Pr2MoveResponse()
        
        pose_requested = request.pose
        joints_array_requested = request.joints_array
        movement_type_requested = request.movement_type.data
        
        if movement_type_requested == "TCP":
            move_response.success = self.ee_traj(pose_requested)
        elif movement_type_requested == "JOINTS":
            move_response.success = self.joint_traj(joints_array_requested)
        else:
            rospy.logerr("Asked for non supported movement type==>"+str(movement_type_requested))
        
        return move_response.success
        
    def ee_traj(self, pose, group_name = "right_arm"):
        
        result = False
        
        if group_name in self.moveit_groups_dict:
        
            moveit_grup_obj = self.moveit_groups_dict[group_name]
        
            pose_frame = moveit_grup_obj.get_pose_reference_frame()
            rospy.loginfo("pose_frame==>"+str(pose_frame))
            
            
            if pose_frame != "/world":
                new_reference_frame = "/world"
                moveit_grup_obj.set_pose_reference_frame(new_reference_frame)
            
                pose_frame = moveit_grup_obj.get_pose_reference_frame()
                rospy.logerr("pose_frame==>"+str(pose_frame))
            else:
                rospy.logwarn("pose_frame OK, ==>"+str(pose_frame))
            
            
            
            moveit_grup_obj.set_pose_target(pose)
            
            result = self.execute_trajectory(moveit_grup_obj)
        
        else:
            
            rospy.logerr("MoveitGroup Requested doesnt exist==>"+str(group_name))
            
        
        return result
        
    def joint_traj(self, positions_array, group_name = "right_arm"):
        
        result = False
        
        if group_name in self.moveit_groups_dict:
        
            moveit_grup_obj = self.moveit_groups_dict[group_name]
        
        
            self.group_variable_values = moveit_grup_obj.get_current_joint_values()
            rospy.logdebug("Group Vars:")
            rospy.logdebug(self.group_variable_values)
            rospy.logdebug("Point:")
            rospy.logdebug(positions_array)
            self.group_variable_values[0] = positions_array[0]
            self.group_variable_values[1] = positions_array[1]
            self.group_variable_values[2] = positions_array[2]
            self.group_variable_values[3] = positions_array[3]
            self.group_variable_values[4] = positions_array[4]
            self.group_variable_values[5] = positions_array[5]
            self.group_variable_values[6] = positions_array[6]
            moveit_grup_obj.set_joint_value_target(self.group_variable_values)
            result =  self.execute_trajectory()
        
        else:
            
            rospy.logerr("MoveitGroup Requested doesnt exist==>"+str(group_name))
        
        return result
        

    def execute_trajectory(self, moveit_grup_obj):
        
        self.plan = moveit_grup_obj.plan()
        result = moveit_grup_obj.go(wait=True)
        
        return result

    def ee_pose(self, group_name = "right_arm"):
        
        gripper_pose = None
        
        if group_name in self.moveit_groups_dict:
            moveit_grup_obj = self.moveit_groups_dict[group_name]
            gripper_pose = moveit_grup_obj.get_current_pose()
            rospy.logdebug("EE POSE==>"+str(gripper_pose))
        else:
            rospy.logerr("MoveitGroup Requested doesnt exist==>"+str(group_name))

        return gripper_pose
        
    def ee_rpy(self, group_name = "right_arm"):
        
        gripper_rpy = None
        
        if group_name in self.moveit_groups_dict:
            gripper_rpy = self.group_right_arm.get_current_rpy()
            rospy.logdebug("EE POSE==>"+str(gripper_rpy))
        else:
            rospy.logerr("MoveitGroup Requested doesnt exist==>"+str(group_name))

        return gripper_rpy
        

def Test1_get_ee_pose():
    move_pr2_obj = MovePR2()
    move_pr2_obj.ee_pose()
    rospy.spin()
     
def Test2_get_ee_rpy():
    move_pr2_obj = MovePR2()
    move_pr2_obj.ee_rpy()
    rospy.spin()
     
def Test3_move_rightarm():
    move_pr2_obj = MovePR2()
    
    """
    InitPose:
    
    position:
    x: -0.0377754141785
    y: -0.662459908134
    z: 1.29999835891
  orientation:
    x: -0.512647205153
    y: -0.526060636653
    z: -0.473572200618
    w: 0.485986029032
    
    """
    
    
    end_effector_pose = Pose()
    
    """
    Bicuit pose
    pick_pose:
  position: {x: 0.56, y: -0.24, z: 0.97}
  orientation: {x: 0.5, y: 0.5, z: -0.5, w: 0.5}
    """
    
    # Prepick pose Biscuits
    end_effector_pose.position.x = 0.56
    end_effector_pose.position.y = -0.24
    end_effector_pose.position.z = 0.97
    
    end_effector_pose.orientation.x = 0.5
    end_effector_pose.orientation.y = 0.5
    end_effector_pose.orientation.z = -0.5
    end_effector_pose.orientation.w = 0.5
     
    move_response = Pr2MoveResponse()
    move_response.success = move_pr2_obj.ee_traj(   pose = end_effector_pose,
                                                    group_name = "right_arm")

    rospy.spin()


def Test4_move_leftarm():
    move_pr2_obj = MovePR2()
    
    """
    Initila Pose
      position:
    x: -0.0377399293174
    y: 0.662381672407
    z: 1.30002783644
  orientation:
    x: 0.512720601674
    y: -0.526108503211
    z: 0.473527342165
    w: 0.485900487437
    """
    
    
    end_effector_pose = Pose()
    
    """
    Soap2 pose
    pick_pose:
  position: {x: 0.46, y: 0.23, z: 0.95}
  orientation: {x: 0.293, y: 0.643, z: -0.293, w: 0.643}
    """
    
    # Init pose
    end_effector_pose.position.x = -0.0377399293174
    end_effector_pose.position.y = 0.662381672407
    end_effector_pose.position.z = 1.30002783644
    
    end_effector_pose.orientation.x = 0.512720601674
    end_effector_pose.orientation.y = -0.526108503211
    end_effector_pose.orientation.z = 0.473527342165
    end_effector_pose.orientation.w = 0.485900487437
     
    move_response = Pr2MoveResponse()
    move_response.success = move_pr2_obj.ee_traj(   pose = end_effector_pose,
                                                    group_name = "left_arm")
                                                    
                                                    
    # Init pose
    # Prepick pose Biscuits
    end_effector_pose.position.x = 0.56
    end_effector_pose.position.y = 0.24
    end_effector_pose.position.z = 0.97
    
    end_effector_pose.orientation.x = 0.5
    end_effector_pose.orientation.y = 0.5
    end_effector_pose.orientation.z = -0.5
    end_effector_pose.orientation.w = 0.5
     
    move_response = Pr2MoveResponse()
    move_response.success = move_pr2_obj.ee_traj(   pose = end_effector_pose,
                                                    group_name = "left_arm")

    rospy.spin()
    
    
def Test5_get_ee_pose_leftarm():
    move_pr2_obj = MovePR2()
    move_pr2_obj.ee_pose(group_name = "left_arm")
    rospy.spin()
    
    
def Test6_move_left_and_right_arm():
    move_pr2_obj = MovePR2()
    
    end_effector_pose = Pose()
    

    # Prepick pose Biscuits
    end_effector_pose.position.x = 0.56
    end_effector_pose.position.y = -0.24
    end_effector_pose.position.z = 0.97
    
    end_effector_pose.orientation.x = 0.5
    end_effector_pose.orientation.y = 0.5
    end_effector_pose.orientation.z = -0.5
    end_effector_pose.orientation.w = 0.5
     
    move_response = Pr2MoveResponse()
    move_response.success = move_pr2_obj.ee_traj(   pose = end_effector_pose,
                                                    group_name = "right_arm")
                                                    
                                                    
    # Init pose
    # Prepick pose Biscuits
    end_effector_pose.position.x = 0.56
    end_effector_pose.position.y = 0.24
    end_effector_pose.position.z = 0.97
    
    end_effector_pose.orientation.x = 0.5
    end_effector_pose.orientation.y = 0.5
    end_effector_pose.orientation.z = -0.5
    end_effector_pose.orientation.w = 0.5
     
    move_response = Pr2MoveResponse()
    move_response.success = move_pr2_obj.ee_traj(   pose = end_effector_pose,
                                                    group_name = "left_arm")

    rospy.spin()


if __name__ == '__main__':
    rospy.init_node('pr2_move_node', anonymous=True, log_level=rospy.DEBUG)
    Test6_move_left_and_right_arm()

Opening MoveIt! Setup Assistant

To get data from the pr2_moveit package, the best way is to access it through the Moveit Wizard:

roslaunch moveit_setup_assistant setup_assistant.launch

Once launched that command, in order to see the window of the setup assistant, you need to open the Graphical Tools by clicking (Tools->Graphical Tools):

Launching Graphical Tools in ROSDS

Launching Graphical Tools in ROSDS

then the Setup Assistant will appear:

To better understand how to setup MoveIt!, now we recommend you check the video (https://youtu.be/wNGIrYtidME?t=277) that contains detailed explanation. In the video, we also give a detailed explanation about the file used to move the arms.

Youtube Video

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Keep pushing your ROS Learning.