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drawing-robot-ros2/examples/py/ex_follow_target.py

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Python
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#!/usr/bin/env python3
"""Example that uses MoveIt 2 to follow a target inside Ignition Gazebo"""
import rclpy
from geometry_msgs.msg import Pose, PoseStamped
from pymoveit2 import MoveIt2
from pymoveit2.robots import panda
from rclpy.callback_groups import ReentrantCallbackGroup
from rclpy.node import Node
from rclpy.qos import QoSProfile
class MoveItFollowTarget(Node):
def __init__(self):
super().__init__("ex_follow_target_py")
# Create callback group that allows execution of callbacks in parallel without restrictions
self._callback_group = ReentrantCallbackGroup()
# Create MoveIt 2 interface
self._moveit2 = MoveIt2(
node=self,
joint_names=panda.joint_names(),
base_link_name=panda.base_link_name(),
end_effector_name=panda.end_effector_name(),
group_name=panda.MOVE_GROUP_ARM,
execute_via_moveit=True,
callback_group=self._callback_group,
)
# Use upper joint velocity and acceleration limits
self._moveit2.max_velocity = 1.0
self._moveit2.max_acceleration = 1.0
# Create a subscriber for target pose
self.__previous_target_pose = Pose()
self.create_subscription(
msg_type=PoseStamped,
topic="/target_pose",
callback=self.target_pose_callback,
qos_profile=QoSProfile(depth=1),
callback_group=self._callback_group,
)
self.get_logger().info("Initialization successful.")
def target_pose_callback(self, msg: PoseStamped):
"""
Plan and execute trajectory each time the target pose is changed
"""
# Return if target pose is unchanged
if msg.pose == self.__previous_target_pose:
return
self.get_logger().info("Target pose has changed. Planning and executing...")
# Plan and execute motion
self._moveit2.move_to_pose(
position=msg.pose.position,
quat_xyzw=msg.pose.orientation,
)
# Update for next callback
self.__previous_target_pose = msg.pose
def main(args=None):
rclpy.init(args=args)
target_follower = MoveItFollowTarget()
executor = rclpy.executors.MultiThreadedExecutor(2)
executor.add_node(target_follower)
executor.spin()
rclpy.shutdown()
exit(0)
if __name__ == "__main__":
main()