Add obstacle avoidance

src/obstacle_avoidance/obstacle_avoidance/obstacle_avoidance.py

+#!/usr/bin/env python3
+
+import rclpy
+from rclpy.node import Node
+from math import isinf
+from sensor_msgs.msg import LaserScan
+from autominy_msgs.msg import SpeedCommand, NormalizedSteeringCommand
+
+class obstacleAvoidance(Node):
+    def __init__(self):
+        super().__init__("obstacle_avoidance")
+        self.lidar_sub = self.create_subscription(LaserScan, "/sensors/rplidar/scan", self.lidar_callback, 10)
+        self.speed_pub = self.create_publisher(SpeedCommand, "actuators/speed", 10)
+        self.steering_pub = self.create_publisher(NormalizedSteeringCommand, "actuators/steering_normalized", 10)
+    
+    def lidar_callback(self, msg):
+        distances = msg.ranges
+        front_distance_min = min(distances[:15] + distances[-15:])
+        front_left_distance_mean = sum(distances[:30]) / 30
+        front_right_distance_mean = sum(distances[-30:]) / 30
+
+        if front_distance_min < 1 and front_right_distance_mean <= front_left_distance_mean:
+            steering_angle = 0.8
+        elif front_distance_min < 1 and front_left_distance_mean < front_right_distance_mean:
+            steering_angle = -0.8
+        else:
+            steering_angle = 0.0
+        steering_cmd = NormalizedSteeringCommand()   
+        steering_cmd.value = steering_angle
+        steering_cmd.header.stamp = self.get_clock().now().to_msg()
+        self.steering_pub.publish(steering_cmd)
+        self.get_logger().info(f'Publish steering: {steering_angle}')
+
+        min_distance = min(distances)
+        if min_distance <= 0 or isinf(min_distance):
+            speed = 0.0
+        else:
+            speed = 0.3
+        speed_cmd = SpeedCommand()
+        speed_cmd.value = speed
+        speed_cmd.header.stamp = self.get_clock().now().to_msg()
+        self.speed_pub.publish(speed_cmd)
+
+
+def main(args = None):
+    rclpy.init(args=args)
+    node = obstacleAvoidance()
+    rclpy.spin(node)
+    node.destroy_node()
+    rclpy.shutdown()
+
+
+if __name__ == '__main__':
+    main()

src/obstacle_avoidance/package.xml

+<?xml version="1.0"?>
+<?xml-model href="http://download.ros.org/schema/package_format3.xsd" schematypens="http://www.w3.org/2001/XMLSchema"?>
+<package format="3">
+  <name>obstacle_avoidance</name>
+  <version>0.0.0</version>
+  <description>TODO: Package description</description>
+  <maintainer email="eber03@zedat.fu-berlin.de">rebecca</maintainer>
+  <license>TODO: License declaration</license>
+
+  <test_depend>ament_copyright</test_depend>
+  <test_depend>ament_flake8</test_depend>
+  <test_depend>ament_pep257</test_depend>
+  <test_depend>python3-pytest</test_depend>
+
+  <export>
+    <build_type>ament_python</build_type>
+  </export>
+</package>

src/obstacle_avoidance/setup.cfg

+[develop]
+script_dir=$base/lib/obstacle_avoidance
+[install]
+install_scripts=$base/lib/obstacle_avoidance

src/obstacle_avoidance/setup.py

+from setuptools import find_packages, setup
+
+package_name = 'obstacle_avoidance'
+
+setup(
+    name=package_name,
+    version='0.0.0',
+    packages=find_packages(exclude=['test']),
+    data_files=[
+        ('share/ament_index/resource_index/packages',
+            ['resource/' + package_name]),
+        ('share/' + package_name, ['package.xml']),
+    ],
+    install_requires=['setuptools'],
+    zip_safe=True,
+    maintainer='rebecca',
+    maintainer_email='eber03@zedat.fu-berlin.de',
+    description='TODO: Package description',
+    license='TODO: License declaration',
+    tests_require=['pytest'],
+    entry_points={
+        'console_scripts': [
+            'obstacle_avoidance = obstacle_avoidance.obstacle_avoidance:main'
+        ],
+    },
+)

src/obstacle_avoidance/test/test_copyright.py

+# Copyright 2015 Open Source Robotics Foundation, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from ament_copyright.main import main
+import pytest
+
+
+# Remove the `skip` decorator once the source file(s) have a copyright header
+@pytest.mark.skip(reason='No copyright header has been placed in the generated source file.')
+@pytest.mark.copyright
+@pytest.mark.linter
+def test_copyright():
+    rc = main(argv=['.', 'test'])
+    assert rc == 0, 'Found errors'

src/obstacle_avoidance/test/test_flake8.py

+# Copyright 2017 Open Source Robotics Foundation, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from ament_flake8.main import main_with_errors
+import pytest
+
+
+@pytest.mark.flake8
+@pytest.mark.linter
+def test_flake8():
+    rc, errors = main_with_errors(argv=[])
+    assert rc == 0, \
+        'Found %d code style errors / warnings:\n' % len(errors) + \
+        '\n'.join(errors)

src/obstacle_avoidance/test/test_pep257.py

+# Copyright 2015 Open Source Robotics Foundation, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from ament_pep257.main import main
+import pytest
+
+
+@pytest.mark.linter
+@pytest.mark.pep257
+def test_pep257():
+    rc = main(argv=['.', 'test'])
+    assert rc == 0, 'Found code style errors / warnings'