时间戳

首页 > 解决方案 > 为什么 ROS Publisher 不发布值？

python - 为什么 ROS Publisher 不发布值？

问题描述

我目前正在尝试编写一个 Python ROS 程序，该程序可以作为 ROS 节点（使用 rosrun）执行，该程序实现在单独的 Python 文件 arm.py 中声明的 defs（可在：https ://github.com/nortega1/dvrk -ros/.. )。该程序最初检查手臂的当前笛卡尔位置。随后，当提供手臂必须通过的一系列点时，程序计算一个多项式方程，并给定一系列 x 值，程序计算方程以找到相应的 y 值。

在该arm.py文件中，有一个发布set_position_cartesian_pub者将手臂的笛卡尔位置设置如下：

self.__set_position_cartesian_pub = rospy.Publisher(self.__full_ros_namespace + '/set_position_cartesian', Pose, latch = True, queue_size = 1)

问题是发布者 set_position_cartesian 没有将 newPose 的值发布给机器人 - 任何人都可以找出问题所在吗？我可以确认 def lagrange 正确计算了 x 和 y 坐标的值，这些值通过命令 rospy.loginfo(newPose) 打印到终端。任何帮助将不胜感激，因为我在过去 2 天里一直在尝试解决这个问题！

#! /usr/bin/python
import rospy
import sys
from std_msgs.msg import String, Bool, Float32
from geometry_msgs.msg import Pose
from geometry_msgs.msg import PoseStamped
from geometry_msgs.msg import Vector3
from geometry_msgs.msg import Quaternion
from geometry_msgs.msg import Wrench

class example_application:

def callback(self, data):
  self.position_cartesian_current = data.pose
  rospy.loginfo(data.pose)

def configure(self,robot_name):
    self._robot_name = 'PSM1'
    ros_namespace = '/dvrk/PSM1'
    rospy.Subscriber('/dvrk/PSM1/position_cartesian_current', PoseStamped, self.callback)
    self.set_position_cartesian = rospy.Publisher('/dvrk/PSM1/set_position_cartesian', Pose, latch=True, queue_size = 10)
    rospy.sleep(3)
    rospy.init_node('listener', anonymous=True)
    rospy.spin()

def lagrange(self, f, x):
 total = 0
 n = len(f)
 for i in range(n):
  xi, yi = f[i]
  def g(i, n):
   g_tot = 1
   for j in range(n):
    if i == j:
     continue
    xj, yj = f[j]
    g_tot *= (x - xj) / float(xi - xj)

   return g_tot

  total += yi * g(i, n)
 return total

def trajectoryMover(self):
    newPose = Pose()
    points =[(0.0156561,0.123151),(0.00715134,0.0035123151),(0.001515177,0.002123151),(0.0071239751,0.09123150)]
    xlist = [i*0.001 for i in range(10)]
    ylist = [self.lagrange(points, xlist[i])*0.001 for i in range(10)]
    for x, y in zip(xlist, ylist):
        newPose.position.x = x
        newPose.position.y = y
        newPose.position.z = 0.001
        newPose.orientation.x = 0.001
        newPose.orientation.y = 0.001
        newPose.orientation.z = 0.005
        newPose.orientation.w = 0.002
        rospy.sleep(1)
        self.set_position_cartesian.publish(newPose)
        rospy.loginfo(newPose)
        rospy.spin()

def run(self):
    # self.home()
    self.trajectoryMover()

if __name__ == '__main__':
    try:
        if (len(sys.argv) != 2):
            print(sys.argv[0] + ' requires one argument, i.e. name of dVRK arm')
    else:
        application = example_application()
        application.configure(sys.argv[1])
        application.run()

except rospy.ROSInterruptException:
    pass

标签： pythonros

解决方案

您没有发布，因为代码在rospy.spin()您调用时停止application.configure()。据我了解您正在尝试做什么，该代码将向一个主题发布 10 个姿势，然后您就不再需要它了。

我已经移动了 的位置rospy.spin()，但是代码需要比这更多的修改。

#! /usr/bin/python
import rospy
import sys
from std_msgs.msg import String, Bool, Float32
from geometry_msgs.msg import Pose
from geometry_msgs.msg import PoseStamped
from geometry_msgs.msg import Vector3
from geometry_msgs.msg import Quaternion
from geometry_msgs.msg import Wrench

class example_application(object):
    def callback(self, data):
        self.position_cartesian_current = data.pose
        rospy.loginfo(data.pose)

    def configure(self,robot_name):
        self._robot_name = 'PSM1'
        ros_namespace = '/dvrk/PSM1'
        rospy.Subscriber('/dvrk/PSM1/position_cartesian_current', PoseStamped, self.callback)
        self.set_position_cartesian = rospy.Publisher('/dvrk/PSM1/set_position_cartesian', Pose, latch=True, queue_size = 10)

    def lagrange(self, f, x):
        total = 0
        n = len(f)
        for i in range(n):
            xi, yi = f[i]
            def g(i, n):
                g_tot = 1
                for j in range(n):
                    if i == j:
                        continue
                    xj, yj = f[j]
                    g_tot *= (x - xj) / float(xi - xj)

                return g_tot

            total += yi * g(i, n)
        return total

    def trajectoryMover(self):
        newPose = Pose()
        points =[(0.0156561,0.123151),(0.00715134,0.0035123151),(0.001515177,0.002123151),(0.0071239751,0.09123150)]
        xlist = [i*0.001 for i in range(10)]
        ylist = [self.lagrange(points, xlist[i])*0.001 for i in range(10)]
        for x, y in zip(xlist, ylist):
            newPose.position.x = x
            newPose.position.y = y
            newPose.position.z = 0.001
            newPose.orientation.x = 0.001
            newPose.orientation.y = 0.001
            newPose.orientation.z = 0.005
            newPose.orientation.w = 0.002
            self.set_position_cartesian.publish(newPose)
            rospy.loginfo(newPose)

    def run(self):
        # self.home()
        self.trajectoryMover()

if __name__ == '__main__':
    if (len(sys.argv) != 2):
        print(sys.argv[0] + ' requires one argument, i.e. name of dVRK arm')
    else:
        application = example_application()
        application.configure(sys.argv[1])
        application.run()

    try:
        rospy.spin()
    except KeyboardInterrupt:
        rospy.loginfo("Keyboard Interrupt")

考虑到：

  • 使脚本参数成为节点的参数。
  • 将configure方法转移到__init__方法。
  • 把g()功能放在外面lagrange()。

使用相对主题名称而不是绝对主题名称是一个好习惯（绝对：主题名称以 开头/，例如：）'/dvrk/PSM1'。

推荐阅读