2、Lidar avoiding

Function package：~/transbot_ws/src/transbot_laser

Introduction of lidar obstacle avoidance:

-Set lidar detection angle and response distance -After turning on the trolley, the trolley drives in a straight line without obstacles

-Determine the direction of obstacles appearing in the car (front left, front right, straight ahead) -Respond to the position of the obstacle in the car (turn left, turn right, turn left in a big circle, turn right in a big circle)

• Set lidar detection angle and response distance
• After turning on the robot, the trolley drives in a straight line without obstacles
• Based on the robot, determine the direction of the obstacle (front left, front right, straight ahead)
• Let the robot react according to the position of the obstacle (turn left, turn right, turn left for long time, turn right for long time)

2.1、Instructions

Start up

roslaunch transbot_laser laser_Avoidance.launch

Dynamic debugging parameters

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rosrun rqt_reconfigure rqt_reconfigure

Parameter analysis:

[Switch] Click the box in front of [switch], the value of [switch] is True, and the car will stop. [Switch] The default is False, and the car moves.

View node

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rqt_graph

2.2、Source code analysis

launch file

• base.launch

x
<launch>
    <!-- Start the lidar node-->
    <include file="$(find rplidar_ros)/launch/rplidar.launch"/>
    <!-- Dynamic debugging tool node -->
<!--    <node pkg="rqt_reconfigure" type="rqt_reconfigure" name="rqt_reconfigure" output="screen"/>-->
    <!-- Start the car chassis drive node-->
    <node pkg="transbot_bringup" type="transbot_driver.py" name="transbot_node" required="true" output="screen">
        <param name="imu" value="/transbot/imu"/>
        <param name="vel" value="/transbot/get_vel"/>
    </node>
    <!-- Handle control node -->
    <include file="$(find transbot_ctrl)/launch/transbot_joy.launch"/>
</launch>

• laser_Avoidance.launch

x
<launch>
    <!-- Start base.launch file-->
    <include file="$(find transbot_laser)/launch/base.launch"/>
    <!-- Start the lidar obstacle avoidance node -->
    <node name='laser_Avoidance' pkg="transbot_laser" type="laser_Avoidance.py" required="true" output="screen"/>
</launch>

py code：~/transbot_ws/src/transbot_laser/scripts/laser_Avoidance.py

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        if self.front_warning > 10 and self.Left_warning > 10 and self.Right_warning > 10:
            # print ('1、turn right')
            ... ...
        elif self.front_warning > 10 and self.Left_warning <= 10 and self.Right_warning > 10:
            # print ('2、turn left')
            ... ...
            if self.Left_warning > 10 and self.Right_warning <= 10:
                # print ('3、turn right')
                ... ...
        elif self.front_warning > 10 and self.Left_warning > 10 and self.Right_warning <= 10:
            # print ('4、turn right')
            ... ...
            if self.Right_warning <= 10 and self.Left_warning > 10:
                # print ('5、turn left')
                ... ...
        elif self.front_warning > 10 and self.Left_warning < 10 and self.Right_warning < 10:
            # print ('6、turn right')
            ... ...
        elif self.front_warning < 10 and self.Left_warning > 10 and self.Right_warning > 10:
            # print ('7、turn right')
            ... ...
        elif self.front_warning < 10 and self.Left_warning > 10 and self.Right_warning <= 10:
            # print ('8、turn right')
            ... ...
        elif self.front_warning < 10 and self.Left_warning <= 10 and self.Right_warning > 10:
            # print ('9、turn left')
            ... ...
        else:
            # print ('10、advance')
            ... ...

According to the obstacle, the position of appearance, set up the different state of the trolley.

Source code parameter analysis: