From 05b4cb8abd629d753a8ff86fca4e3cfd5547be4b Mon Sep 17 00:00:00 2001
From: sberestov <beresta.izh@gmail.com>
Date: Wed, 27 Nov 2024 23:26:22 +0300
Subject: [PATCH 1/2] Added a control file for waterstrider

---
 lesson_07/step_1.py | 100 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 100 insertions(+)
 create mode 100644 lesson_07/step_1.py

diff --git a/lesson_07/step_1.py b/lesson_07/step_1.py
new file mode 100644
index 0000000..0aef551
--- /dev/null
+++ b/lesson_07/step_1.py
@@ -0,0 +1,100 @@
+import rclpy
+from rclpy.node import Node
+                                
+from std_msgs.msg import Float64
+from geometry_msgs.msg import Twist
+from geometry_msgs.msg import PoseStamped
+
+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 get_distance(delta_point):
+    return sum(map(lambda x: x**2, delta_point))**0.5
+
+def get_course_to_point(delta_point):
+    ln = get_distance(delta_point)
+    if ln:
+        dxn = delta_point[0]/ln
+        dyn = delta_point[1]/ln
+        ang = math.acos(dxn)
+        if dyn < 0:
+            ang = 2*math.pi - ang
+        return ang
+    return 0
+
+def get_dist_course(delta_point):
+    dist = get_distance(delta_point)
+    course = get_course_to_point(delta_point)
+    return dist, course
+
+def get_delta_point(from_point, to_point):
+    return [to_point[0] - from_point[0], to_point[1] - from_point[1]]
+
+
+class RurMover(Node):
+    def __init__(self):
+        super().__init__('controller')
+        self.CONTROLER_PERIOD = 1/10
+        self.DIST_THRESHOLD = 0.5
+
+        self.publisher_twist = self.create_publisher(Twist, '/waterstrider/twist_command', 10)
+
+        zero_point = Float64()
+        zero_point.data = 0.0
+        self.heading_pub = self.create_publisher(Float64, '/waterstrider/pid_heading/state', 10)
+        self.heading_setpoint = self.create_publisher(Float64, '/waterstrider/pid_heading/setpoint', 10)
+        self.heading_result = self.create_subscription(Float64, '/waterstrider/pid_heading/output', self.pid_heading_callback, 10)
+        self.heading_setpoint.publish(zero_point)
+
+        self.create_subscription(PoseStamped, '/waterstrider/ground_truth_to_tf_waterstrider/pose', self.pose_callback, 10)
+
+        self.heading = 0
+        self.self_point = [0.0, 0.0]
+        self.goal_point = [0.0, 0.0]
+
+        self.timer = self.create_timer(self.CONTROLER_PERIOD, self.update)
+        self.result = Twist()
+
+    def update(self):
+        self.publisher_twist.publish(self.result)
+
+    def pose_callback(self, msg):
+        desired_heading = Float64()
+        current_heading = Float64()
+
+        delta_point = get_delta_point(self.self_point, self.goal_point)
+        desired_heading.data = get_dist_course(delta_point)
+        self.heading_setpoint.publish(desired_heading)
+        self.heading_pub.publish(current_heading)
+
+
+    def pid_distance_callback(self, msg):
+        self.result.linear.x = -1*msg.data
+
+    def pid_heading_callback(self, msg):
+        self.result.angular.z = -1*msg.data
+
+    def log_info(self, msg: str) -> None:
+        self.get_logger().info(msg)
+
+
+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
-- 
GitLab


From 7ee416901f2c198c0d62b6fc4c1590b862b701c7 Mon Sep 17 00:00:00 2001
From: sberestov <beresta.izh@gmail.com>
Date: Sun, 1 Dec 2024 16:06:22 +0300
Subject: [PATCH 2/2] Minor changes to the pid-node

---
 lesson_07/pid_node.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lesson_07/pid_node.py b/lesson_07/pid_node.py
index 6c390a5..45c5936 100644
--- a/lesson_07/pid_node.py
+++ b/lesson_07/pid_node.py
@@ -4,7 +4,7 @@ import rclpy
 from rclpy.node import Node
 from std_msgs.msg import Float64
 from rcl_interfaces.msg import SetParametersResult
-
+import math
 
 class PID(Node):
     config = {}
@@ -53,7 +53,7 @@ class PID(Node):
         self.pub_result.publish(message)
 
     def angular_constraint(self, e):
-        return (e + 180.0) % (2 * 180.0) - 180.0
+        return (e + math.pi) % (2 * math.pi) - math.pi
 
     def update(self, state):
         error = self.sp - state if not self.config['inverted'] else state - self.sp
-- 
GitLab