ROS学习之29日 ros中的速度平滑处理

参考 https://www.cnblogs.com/21207-iHome/p/8118875.html



ros中的规划层已经有加速度的限制,  base/dwa_local_planner_params.yaml

  acc_lim_x: 2.5            # default: 2.5
  acc_lim_y: 0.0
  acc_lim_theta: 3.2        # default: 3.2

但是输出的还是不够友好导致机器人行走不流畅，那么就在速度接口这边就要执行一个平滑的过程。通过使用速度插值的包 yocs_velocity_smoother, 来达到差动轮上持续平滑的速度输出.

yocs_velocity_smoother是一个速度、加速度限制器，用来防止robot navigation的速度/转速过快，加速度/快减速过大

sudo apt-get install ros-kinetic-yocs-velocity-smoother 

	
	
安装过程出现错误, 清华ROS mirror服务区 gpt key 错误, 解决方式
wget http://packages.ros.org/ros.key -O - | sudo apt-key add -




	
	

	

		
		
订阅的话题
raw_cmd_vel：Input velocity commands. 原始速度指令
odometry：We compare the output velocity commands to measured velocity to ensure we don't create very big jumps in the velocity profile.
robot_cmd_vel：Alternatively, we can also compare the output velocity commands to end robot velocity commands to ensure we don't create very big jumps in the velocity profile. See robot_feedback parameter description below for more details.

发布的话题
smooth_cmd_vel：Smoothed output velocity commands respecting velocity and acceleration limits. 限制幅度后的速度

	




在 big_navigation.launch 中加入


	
	

		
<!-- velocity smoother -->
  <include file="$(find big_navigation)/launch/velocity_smoother.launch" />
	



velocity_smoother.launch 的内容为

	
	

	

		
		
<launch>
  <arg name="node_name" default="velocity_smoother"/>
  <arg name="nodelet_manager_name" default="nodelet_manager"/>
  <arg name="config_file" default="$(find big_navigation)/param/velocity_smoother.yaml"/>
  <arg name="raw_cmd_vel_topic" default="cmd_vel"/>  //输入项, Nav时的速度
  <arg name="smooth_cmd_vel_topic" default="smooth_cmd_vel"/> //输出项, 平滑后的速度
  <arg name="robot_cmd_vel_topic" default="cmd_vel"/> //输入项, 底盘上报的速度.本来对应 rc100
  <arg name="odom_topic" default="odom"/> //输入项

  <!-- nodelet manager -->
  <node pkg="nodelet" type="nodelet" name="$(arg nodelet_manager_name)" args="manager"/>

  <node pkg="nodelet" type="nodelet" name="$(arg node_name)" args="load yocs_velocity_smoother/VelocitySmootherNodelet $(arg nodelet_manager_name)" output="screen">

    <!-- parameters -->
    <rosparam file="$(arg config_file)" command="load"/>

    <!-- Subscribed Topics -->
    <remap from="$(arg node_name)/raw_cmd_vel" to="$(arg raw_cmd_vel_topic)"/> <!-- velocity commands Input -->
    <remap from="$(arg node_name)/odometry" to="$(arg odom_topic)"/> <!-- Robot velocity feedbacks -->
    <remap from="$(arg node_name)/robot_cmd_vel" to="$(arg robot_cmd_vel_topic)"/> <!-- Robot velocity feedbacks -->

    <!-- Published Topics -->
    <remap from="$(arg node_name)/smooth_cmd_vel" to="$(arg smooth_cmd_vel_topic)"/> <!-- velocity commands Output -->
  </node>
</launch>

	


velocity_smoother.yaml内容 

	
	

	

		
		
# Mandatory parameters
speed_lim_v: 0.26  # Linear velocity limit
speed_lim_w: 0.6  # Angular velocity limit

accel_lim_v: 2.5  # Linear acceleration limit
accel_lim_w: 3.2  # Angular acceleration limit

# Optional parameters
frequency: 35.0   # Output messages rate. The velocity smoother keeps it regardless incoming messages rate, interpolating whenever necessary
decel_factor: 1.0 # Deceleration/acceleration ratio. Useful to make deceleration more aggressive

# Robot velocity feedback type:
#  0 - none
#  1 - odometry
#  2 - end robot commands
robot_feedback: 2

	


实测结果发现:

有进步, 但是效果不是非常明显, 还是有些行进过程中的卡顿, 所以最根本的方法就是把速度降低.