手把手教你用Gazebo仿真UUV水下机器人

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2020年6月1日 10时03分

前言

本节教程演示UUV的一些玩法,基于开源项目UUV,官方介绍文档:uuvsimulator

仿真环境

系统:ubuntu16.04
软件:ROS – kinetic
仿真:gazebo7

安装仿真软件

官网介绍目前支持的版本有三个:kunetic、lunar、melodic
安装命令:

kinetic版本:sudo apt install ros-kinetic-uuv-simulator
lunar版本:sudo apt install ros-lunar-uuv-simulator
melodic版本:sudo apt install ros-melodic-uuv-simulator

如果希望从源码安装的朋友参考这里:源码安装教程
这里不推荐源码安装,因为看了下github项目的issue中很多人显示安装报错,所以emmm省的折腾。

启动AUV海底世界

启动带海底的世界执行命令:

roslaunch uuv_gazebo_worlds auv_underwater_world.launch

水世界效果图如下(还是很帅的天空的云和海水都是在动的):
手把手教你用Gazebo仿真UUV水下机器人插图

启动赫尔库勒斯沉船的世界执行命令:

roslaunch uuv_gazebo_worlds herkules_ship_wreck.launch

手把手教你用Gazebo仿真UUV水下机器人插图(1)

启动湖泊

roslaunch uuv_gazebo_worlds lake.launch

手把手教你用Gazebo仿真UUV水下机器人插图(2)

其他的一些场景

roslaunch uuv_gazebo_worlds mangalia.launch
roslaunch uuv_gazebo_worlds munkholmen.launch
roslaunch uuv_gazebo_worlds ocean_waves.launch

!注意这里的海浪都只是视觉效果不会将波浪的载荷加载在水下机器人上

水下机器人运动控制

启动环境和水下机器人pid控制

执行命令:

roslaunch uuv_gazebo start_pid_demo_with_teleop.launch

这里机器人的速度控制还是经典的cmd_vel话题,我们可以自己创建速度控制脚本teletop.py:

#!/usr/bin/env python
import rospy
from geometry_msgs.msg import Twist
import sys, select, os
if os.name == 'nt':
  import msvcrt
else:
  import tty, termios

FETCH_MAX_LIN_VEL = 5
FETCH_MAX_ANG_VEL = 2.84

LIN_VEL_STEP_SIZE = 0.01
ANG_VEL_STEP_SIZE = 0.1

msg = """
Control Your Robot!
---------------------------
Moving around:
        w
   a    s    d
        x

"""

e = """
Communications Failed
"""

def getKey():
    if os.name == 'nt':
      return msvcrt.getch()

    tty.setraw(sys.stdin.fileno())
    rlist, _, _ = select.select([sys.stdin], [], [], 0.1)
    if rlist:
        key = sys.stdin.read(1)
    else:
        key = ''

    termios.tcsetattr(sys.stdin, termios.TCSADRAIN, settings)
    return key

def vels(target_linear_vel, target_angular_vel):
    return "currently:\tlinear vel %s\t angular vel %s " % (target_linear_vel,target_angular_vel)

def makeSimpleProfile(output, input, slop):
    if input > output:
        output = min( input, output + slop )
    elif input < output:
        output = max( input, output - slop )
    else:
        output = input

    return output

def constrain(input, low, high):
    if input < low:
      input = low
    elif input > high:
      input = high
    else:
      input = input

    return input

def checkLinearLimitVelocity(vel):
    vel = constrain(vel, -FETCH_MAX_LIN_VEL, FETCH_MAX_LIN_VEL)
    return vel

def checkAngularLimitVelocity(vel):
    vel = constrain(vel, -FETCH_MAX_ANG_VEL, FETCH_MAX_ANG_VEL)
    return vel

if __name__=="__main__":
    if os.name != 'nt':
        settings = termios.tcgetattr(sys.stdin)

    rospy.init_node('fetch_teleop')
    pub = rospy.Publisher('/rexrov/cmd_vel', Twist, queue_size=10)

    status = 0
    target_linear_vel   = 0.0
    target_angular_vel  = 0.0
    control_linear_vel  = 0.0
    control_angular_vel = 0.0

    try:
        print(msg)
        while(1):
            key = getKey()
            if key == 'w' :
                target_linear_vel = checkLinearLimitVelocity(target_linear_vel + LIN_VEL_STEP_SIZE)
                status = status + 1
                print(vels(target_linear_vel,target_angular_vel))
            elif key == 'x' :
                target_linear_vel = checkLinearLimitVelocity(target_linear_vel - LIN_VEL_STEP_SIZE)
                status = status + 1
                print(vels(target_linear_vel,target_angular_vel))
            elif key == 'a' :
                target_angular_vel = checkAngularLimitVelocity(target_angular_vel + ANG_VEL_STEP_SIZE)
                status = status + 1
                print(vels(target_linear_vel,target_angular_vel))
            elif key == 'd' :
                target_angular_vel = checkAngularLimitVelocity(target_angular_vel - ANG_VEL_STEP_SIZE)
                status = status + 1
                print(vels(target_linear_vel,target_angular_vel))
            elif key == ' ' or key == 's' :
                target_linear_vel   = 0.0
                control_linear_vel  = 0.0
                target_angular_vel  = 0.0
                control_angular_vel = 0.0
                print(vels(target_linear_vel, target_angular_vel))
            else:
                if (key == '\x03'):
                    break

            if status == 20 :
                print(msg)
                status = 0

            twist = Twist()

            control_linear_vel = makeSimpleProfile(control_linear_vel, target_linear_vel, (LIN_VEL_STEP_SIZE/2.0))
            twist.linear.x = control_linear_vel; twist.linear.y = 0.0; twist.linear.z = 0.0

            control_angular_vel = makeSimpleProfile(control_angular_vel, target_angular_vel, (ANG_VEL_STEP_SIZE/2.0))
            twist.angular.x = 0.0; twist.angular.y = 0.0; twist.angular.z = control_angular_vel

            pub.publish(twist)

    except:
        print(e)

    finally:
        twist = Twist()
        twist.linear.x = 0.0; twist.linear.y = 0.0; twist.linear.z = 0.0
        twist.angular.x = 0.0; twist.angular.y = 0.0; twist.angular.z = 0.0
        pub.publish(twist)

    if os.name != 'nt':
        termios.tcsetattr(sys.stdin, termios.TCSADRAIN, settings)

运行脚本就可以控制船运动了:

python teletop.py

生成螺旋线控制水下机器人运动

执行命令启动pid控制和环境:

roslaunch uuv_gazebo start_pid_demo_with_teleop.launch

生成螺旋线并巡线(这里我生成的是2股螺旋线):

roslaunch uuv_control_utils start_helical_trajectory.launch uuv_name:=rexrov n_turns:=2

手把手教你用Gazebo仿真UUV水下机器人插图(3)

发布一组导航点导航

执行命令启动pid控制和环境:

roslaunch uuv_gazebo start_pid_demo_with_teleop.launch

执行命令生成直线路径:

roslaunch uuv_control_utils send_waypoints_file.launch uuv_name:=rexrov interpolator:=linear

手把手教你用Gazebo仿真UUV水下机器人插图(4)

机器人路径根据贝塞尔曲线原理生成,可以保证轨迹上的点速度方向是连续的,并且规定路径点生成的整条路径是必过路径点的。
小编这里写了个二维三阶贝赛尔曲线的路径生成的代码:https://github.com/xmy0916/bezier
大家可以参考参考!

执行命令生成三维贝赛尔曲线路径:

roslaunch uuv_control_utils send_waypoints_file.launch uuv_name:=rexrov interpolator:=cubic

手把手教你用Gazebo仿真UUV水下机器人插图(5)

更多操作参考

项目官方文档
项目github地址

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评论列表(1条)

  • vy59l_1269 2020年7月10日 下午4:36

    在安装好以后,加载水下世界时能出来,但是那个沉船不能加载出来,说Finished loading Gazebo ROS API Plugin.
    链接 gazebo master 也报错 说libcurl: (51) SSL: no alternative certificate subject name matches target host name ‘api.ignitionfuel.org’