sending to a certain position in space using Twist

edit

I am using the human following with OpenCV and I'd like to move the robot to the last observed position. I tried to use move_base which relies on actionlib and map but unfortunately, it is not stable with OpenCV. it shows many warn messages and its movement is uncontrollable.

full code:

#!/usr/bin/env python

import rospy
from move_base_msgs.msg import MoveBaseAction, MoveBaseGoal
import actionlib
from actionlib_msgs.msg import *
from geometry_msgs.msg import Pose, Point, Quaternion

class GoToPose():
    def __init__(self):

        self.goal_sent = False
        rospy.on_shutdown(self.shutdown)
        self.move_base = actionlib.SimpleActionClient("move_base", MoveBaseAction)
        rospy.loginfo("Wait for the action server to come up")
        self.move_base.wait_for_server(rospy.Duration(5))

    def goto(self, pos, quat):
        self.goal_sent = True
        goal = MoveBaseGoal()
        goal.target_pose.header.frame_id = 'base_link'
        goal.target_pose.header.stamp = rospy.Time.now()
        goal.target_pose.pose = Pose(Point(pos['x'], pos['y'], 0.000),
                                     Quaternion(quat['r1'], quat['r2'], quat['r3'], quat['r4']))

        self.move_base.send_goal(goal)
        success = self.move_base.wait_for_result(rospy.Duration(60))
        state = self.move_base.get_state()
        result = False
        if success and state == GoalStatus.SUCCEEDED:
            # We made it!
            result = True
        else:
            self.move_base.cancel_goal()

        self.goal_sent = False
        return result

    def shutdown(self):
        if self.goal_sent:
            self.move_base.cancel_goal()
        rospy.loginfo("Stop")
        rospy.sleep(1)

if __name__ == '__main__':
    try:
        rospy.init_node('nav_test', anonymous=False)
        navigator = GoToPose()
        # Customize the following values so they are appropriate for your location
        position = {'x': 1, 'y' : 0.0}
        quaternion = {'r1': 0.000, 'r2': 0.000, 'r3': 0.000, 'r4': 1.000}

        rospy.loginfo("Go to (%s, %s) pose", position['x'], position['y'])
        success = navigator.goto(position, quaternion)
        if success:
            rospy.loginfo("Hooray, reached the desired pose")
        else:
            rospy.loginfo("The base failed to reach the desired pose")
        # Sleep to give the last log messages time to be sent
        rospy.sleep(1)

    except rospy.ROSInterruptException:
            rospy.loginfo("Ctrl-C caught. Quitting")

So, I'd like to use Twist instead of move_base and keep 'base_link' as the main reference instead of Odom. I got this code here . but it uses Odom as a reference.

please any idea or suggestions, it would be appreciated.