文章目录
- 前言
一、创建编译功能包
二、xacro文件
1、更新robot_base.xacro文件
三、启动模型
四、键盘控制
五、总结
前言
所谓滑移转向,对机器人机身两侧轮子分别进行驱动,通过不同的转速,完成机器人的转向。
一、创建编译功能包
切换到catkin_ws/src目录下,如下:
catkin_create_pkg mbot_sim_gazebo_move urdf xacro
切换到catkin_ws目录下,编译该功能包,如下:
catkin_make mbot_sim_gazebo_move
在该功能包下创建include、src、launch、urdf文件夹,在urdf文件下创建urdf文件夹和xacro文件夹。
二、xacro文件
1、更新robot_base.xacro文件
切换到xacro文件下,更新robot_base文件,文件内容如下:
<?xml version="1.0"?>
<robot name="mbot" xmlns:xacro="http://www.ros.org/wiki/xacro">
<!-- PROPERTY LIST -->
<xacro:property name="M_PI" value="3.1415926"/>
<xacro:property name="base_mass" value="20" />
<xacro:property name="base_radius" value="0.20"/>
<xacro:property name="base_length" value="0.16"/>
<xacro:property name="wheel_mass" value="2" />
<xacro:property name="wheel_radius" value="0.06"/>
<xacro:property name="wheel_length" value="0.025"/>
<xacro:property name="wheel_joint_y" value="0.19"/>
<xacro:property name="wheel_joint_z" value="0.05"/>
<xacro:property name="caster_mass" value="0.5" />
<xacro:property name="caster_radius" value="0.015"/> <!-- wheel_radius - ( base_length/2 - wheel_joint_z) -->
<xacro:property name="caster_joint_x" value="0.18"/>
<!-- Defining the colors used in this robot -->
<material name="yellow">
<color rgba="1 0.4 0 1"/>
</material>
<material name="black">
<color rgba="0 0 0 0.95"/>
</material>
<material name="gray">
<color rgba="0.75 0.75 0.75 1"/>
</material>
<!-- Macro for inertia matrix -->
<xacro:macro name="sphere_inertial_matrix" params="m r">
<inertial>
<mass value="${m}" />
<inertia ixx="${2*m*r*r/5}" ixy="0" ixz="0"
iyy="${2*m*r*r/5}" iyz="0"
izz="${2*m*r*r/5}" />
</inertial>
</xacro:macro>
<xacro:macro name="cylinder_inertial_matrix" params="m r h">
<inertial>
<mass value="${m}" />
<inertia ixx="${m*(3*r*r+h*h)/12}" ixy = "0" ixz = "0"
iyy="${m*(3*r*r+h*h)/12}" iyz = "0"
izz="${m*r*r/2}" />
</inertial>
</xacro:macro>
<!-- Macro for robot wheel -->
<xacro:macro name="wheel" params="prefix reflect">
<joint name="${prefix}_wheel_joint" type="continuous">
<origin xyz="0 ${reflect*wheel_joint_y} ${-wheel_joint_z}" rpy="0 0 0"/>
<parent link="base_link"/>
<child link="${prefix}_wheel_link"/>
<axis xyz="0 1 0"/>
</joint>
<link name="${prefix}_wheel_link">
<visual>
<origin xyz="0 0 0" rpy="${M_PI/2} 0 0" />
<geometry>
<cylinder radius="${wheel_radius}" length = "${wheel_length}"/>
</geometry>
<material name="gray" />
</visual>
<collision>
<origin xyz="0 0 0" rpy="${M_PI/2} 0 0" />
<geometry>
<cylinder radius="${wheel_radius}" length = "${wheel_length}"/>
</geometry>
</collision>
<cylinder_inertial_matrix m="${wheel_mass}" r="${wheel_radius}" h="${wheel_length}" />
</link>
<gazebo reference="${prefix}_wheel_link">
<material>Gazebo/Gray</material>
</gazebo>
<!-- Transmission is important to link the joints and the controller-->
<transmission name="${prefix}_wheel_joint_trans">
<type>transmission_interface/SimpleTransmission</type>
<joint name="${prefix}_wheel_joint" >
<hardwareInterface>hardware_interface/VelocityJointInterface</hardwareInterface>
</joint>
<actuator name="${prefix}_wheel_joint_motor">
<hardwareInterface>hardware_interface/VelocityJointInterface</hardwareInterface>
<mechanicalReduction>1</mechanicalReduction>
</actuator>
</transmission>
</xacro:macro>
<!-- Macro for robot caster -->
<xacro:macro name="caster" params="prefix reflect">
<joint name="${prefix}_caster_joint" type="continuous">
<origin xyz="${reflect*caster_joint_x} 0 ${-(base_length/2 + caster_radius)}" rpy="0 0 0"/>
<parent link="base_link"/>
<child link="${prefix}_caster_link"/>
<axis xyz="0 1 0"/>
</joint>
<link name="${prefix}_caster_link">
<visual>
<origin xyz="0 0 0" rpy="0 0 0"/>
<geometry>
<sphere radius="${caster_radius}" />
</geometry>
<material name="black" />
</visual>
<collision>
<origin xyz="0 0 0" rpy="0 0 0"/>
<geometry>
<sphere radius="${caster_radius}" />
</geometry>
</collision>
<sphere_inertial_matrix m="${caster_mass}" r="${caster_radius}" />
</link>
<gazebo reference="${prefix}_caster_link">
<material>Gazebo/Black</material>
</gazebo>
</xacro:macro>
<xacro:macro name="mbot_base_gazebo">
<link name="base_footprint">
<visual>
<origin xyz="0 0 0" rpy="0 0 0" />
<geometry>
<box size="0.001 0.001 0.001" />
</geometry>
</visual>
</link>
<gazebo reference="base_footprint">
<turnGravityOff>false</turnGravityOff>
</gazebo>
<joint name="base_footprint_joint" type="fixed">
<origin xyz="0 0 ${base_length/2 + caster_radius*2}" rpy="0 0 0" />
<parent link="base_footprint"/>
<child link="base_link" />
</joint>
<link name="base_link">
<visual>
<origin xyz=" 0 0 0" rpy="0 0 0" />
<geometry>
<cylinder length="${base_length}" radius="${base_radius}"/>
</geometry>
<material name="yellow" />
</visual>
<collision>
<origin xyz=" 0 0 0" rpy="0 0 0" />
<geometry>
<cylinder length="${base_length}" radius="${base_radius}"/>
</geometry>
</collision>
<cylinder_inertial_matrix m="${base_mass}" r="${base_radius}" h="${base_length}" />
</link>
<gazebo reference="base_link">
<material>Gazebo/Blue</material>
</gazebo>
<wheel prefix="left" reflect="-1"/>
<wheel prefix="right" reflect="1"/>
<caster prefix="front" reflect="-1"/>
<caster prefix="back" reflect="1"/>
<!-- controller -->
<gazebo>
<plugin name="differential_drive_controller"
filename="libgazebo_ros_diff_drive.so">
<rosDebugLevel>Debug</rosDebugLevel>
<publishWheelTF>true</publishWheelTF>
<robotNamespace>/</robotNamespace>
<publishTf>1</publishTf>
<publishWheelJointState>true</publishWheelJointState>
<alwaysOn>true</alwaysOn>
<updateRate>100.0</updateRate>
<legacyMode>true</legacyMode>
<leftJoint>left_wheel_joint</leftJoint>
<rightJoint>right_wheel_joint</rightJoint>
<wheelSeparation>${wheel_joint_y*2}</wheelSeparation>
<wheelDiameter>${2*wheel_radius}</wheelDiameter>
<broadcastTF>1</broadcastTF>
<wheelTorque>30</wheelTorque>
<wheelAcceleration>1.8</wheelAcceleration>
<commandTopic>cmd_vel</commandTopic>
<odometryFrame>odom</odometryFrame>
<odometryTopic>odom</odometryTopic>
<robotBaseFrame>base_footprint</robotBaseFrame>
</plugin>
</gazebo>
</xacro:macro>
</robot>
三、启动模型
此时的模型带有滑移转向控制器和地图,通过如下命令启动:
roslaunch mbot_sim_gazebo_move robot_gazebo_wg.launch
四、键盘控制
该节点在teleop_twist_keyboard功能包中,需要通过如下命令安装:
sudo apt-get install ros-melodic-teleop-twist-keyboard
rosstack profile
rospack profile
然后通过如下命令,运行该节点:
rosrun teleop_twist_keyboard teleop_twist_keyboard.py
效果如下:
可以看到出现一个带有命令提示的命令行窗口,可以使用u,i,o,j,k,l,m,“<”,“>””等按键移动机器人并设置速度。
各个按键及其功能如下:
U I O
J K L
M < >
K—停止
I、J、<、L—前、左转、后、右转
q/z : 最大速度增加/减少10%
w/x : 仅线性速度增加10%
e/c : 仅角速度增加10%
五、总结
可以通过上述方法,驾驶机器人穿越整个房间,但是我怎么赶脚操控有点难度。。。至此,一个自定义移动机器人的建模与仿真基本结束,下一篇开始接触导航,加油啊。
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