From ec843fc74fb699b668f63637277e8c391663e461 Mon Sep 17 00:00:00 2001
From: Alina <seral.deli.19@bk.ru>
Date: Mon, 11 Nov 2024 11:26:13 +0300
Subject: [PATCH] Write node

---
 lesson_06/step_1.py | 70 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 lesson_06/step_1.py

diff --git a/lesson_06/step_1.py b/lesson_06/step_1.py
new file mode 100644
index 0000000..e552a3a
--- /dev/null
+++ b/lesson_06/step_1.py
@@ -0,0 +1,70 @@
+import rclpy
+from rclpy.node import Node
+from geometry_msgs.msg import Twist
+from geometry_msgs.msg import PoseStamped, Pose
+from std_msgs import Float64
+from tf_transformations import euler_from_quaternion
+import math                                                                    
+
+def angle_diff(a1, a2):
+    a = a1-a2
+    return (a+math.pi)%(2*math.pi)-math.pi
+
+def get_yaw_from_quaternion(q):
+    return euler_from_quaternion([q.x, q.y, q.z, q.w])[2]
+
+def delt(t1,t2):
+    t=t2-t1
+    return t
+
+class RurMover(Node):
+    def __init__(self):
+        super().__init__('controller')
+        self.heading=self.create_publisher(Float64,'/waterstrider/pid/state',10)
+        self.head_setpoint=self.create_publisher(Float64,'waterstrider/pid/setpoint',10)
+        self.result=self.create_subscription(Float64,'waterstrider/pid/output',self.pid_callback,10)
+        self.publisher_twist = self.create_publisher(Twist, '/waterstrider/twist_command', 10)
+        self.pose_subscriber = self.create_subscription(PoseStamped, '/waterstrider/ground_truth_to_tf_waterstrider/pose', self.pose_callback, 10)
+        
+        self.desired_heading = - math.pi / 2
+        self.SIDE_TIME = 20.0
+        self.LINEAR_SPEED = 0.5
+        self.timer = self.create_timer(self.SIDE_TIME, self.pub_timer_callback)
+
+
+    def pose_callback(self, msg):
+        heading = Float64()
+        if self.desired_heading <= math.pi / 2:
+            heading.data = get_yaw_from_quaternion(msg.pose.orientation)
+        elif get_yaw_from_quaternion(msg.pose.orientation) < 0:
+            heading.data = 2 * math.pi + get_yaw_from_quaternion(msg.pose.orientation)
+        self.get_logger().info('current heading: "%f"' % heading.data) 
+        self.get_logger().info('angle setpoint: "%f"' % self.desired_heading) 
+        desired_heading = Float64() 
+        desired_heading.data = self.desired_heading
+        self.heading.publish (heading)
+        self.head_setpoint.publish(desired_heading)
+    def pid_callback(self, msg):
+        pid_out = msg.data
+        msg_pub = Twist()
+        msg_pub.linear.x = self.LINEAR_SPEED
+        msg_pub.angular.z = pid_out
+        self.publisher_twist.publish(msg_pub)
+
+    def pub_timer_callback(self):
+        self.desired_heading += math.pi / 2
+        self.desired_heading %= 2 * math.pi
+        self.get_logger().info('New angle setpoint: "%f"' % self.desired_heading)
+
+def main(args=None):
+    rclpy.init(args=args)
+
+    mover = RurMover()
+
+    rclpy.spin(mover)
+
+    mover.destroy_node()
+    rclpy.shutdown()
+
+if __name__ == '__main__':
+    main()
\ No newline at end of file
-- 
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