mavros/local_position/pose

mavros/local_position/pose是ROS中的一个话题，用于发布机器人的本地位置信息。具体包括机器人在本地坐标系下的位置和姿态信息。该话题通常由mavros节点发布，可以被其他节点订阅，用于实现机器人的定位和导航等功能。

相关问题

kcf无人机跟踪小车ros代码,要求订阅/iris/usb_cam/image_raw话题，发布mavros/setpoint_position/local和/mavros/setpoint_velocity/cmd_vel_unstamped

以下是一个简单的ROS节点示例，用于使用KCF算法跟踪小车并发布位置和速度指令到MAVROS。

#!/usr/bin/env python

import rospy
from sensor_msgs.msg import Image
from cv_bridge import CvBridge
import cv2
import numpy as np
from pyimagesearch.centroidtracker import CentroidTracker
from pyimagesearch.trackableobject import TrackableObject
from geometry_msgs.msg import PoseStamped, Twist

class KCFTrackerNode:
    def __init__(self):
        rospy.init_node('kcf_tracker_node', anonymous=True)

        self.bridge = CvBridge()
        self.ct = CentroidTracker()
        self.trackers = []
        self.trackable_objects = {}

        self.image_sub = rospy.Subscriber('/iris/usb_cam/image_raw', Image, self.image_callback)
        self.position_pub = rospy.Publisher('/mavros/setpoint_position/local', PoseStamped, queue_size=1)
        self.velocity_pub = rospy.Publisher('/mavros/setpoint_velocity/cmd_vel_unstamped', Twist, queue_size=1)

        self.image_width = 640
        self.image_height = 480
        self.focal_length = 600
        self.real_width = 0.5
        self.target_width = 0.1

    def image_callback(self, data):
        cv_image = self.bridge.imgmsg_to_cv2(data, 'bgr8')

        if len(self.trackers) == 0:
            # initialize trackers
            objects = self.ct.update([(0, 0, self.image_width, self.image_height)])
            for (object_id, centroid) in objects.items():
                tracker = cv2.TrackerKCF_create()
                tracker.init(cv_image, (centroid[0], centroid[1], self.target_width * self.focal_length, self.target_width * self.focal_length))
                self.trackers.append(tracker)
                self.trackable_objects[object_id] = TrackableObject(object_id, centroid)

        else:
            # update trackers
            for tracker in self.trackers:
                success, box = tracker.update(cv_image)
                if success:
                    (x, y, w, h) = [int(v) for v in box]
                    centroid = (x + w / 2, y + h / 2)
                    object_id = self.ct.register(centroid)
                    to = self.trackable_objects.get(object_id, None)
                    if to is None:
                        to = TrackableObject(object_id, centroid)
                        self.trackable_objects[object_id] = to
                    else:
                        to.centroids.append(centroid)

        # filter out small objects
        self.trackable_objects = {k: v for k, v in self.trackable_objects.items() if len(v.centroids) > 5 and v.width() > self.image_width * 0.1}

        # update position and velocity commands
        for object_id, to in self.trackable_objects.items():
            x = (to.centroids[-1][0] - self.image_width / 2) * self.real_width / self.focal_length
            y = (to.centroids[-1][1] - self.image_height / 2) * self.real_width / self.focal_length
            z = 2.0

            pose_msg = PoseStamped()
            pose_msg.header.stamp = rospy.Time.now()
            pose_msg.pose.position.x = x
            pose_msg.pose.position.y = y
            pose_msg.pose.position.z = z
            self.position_pub.publish(pose_msg)

            vx = (to.centroids[-1][0] - to.centroids[-2][0]) * self.real_width / self.focal_length
            vy = (to.centroids[-1][1] - to.centroids[-2][1]) * self.real_width / self.focal_length
            vz = 0.0

            vel_msg = Twist()
            vel_msg.linear.x = vx
            vel_msg.linear.y = vy
            vel_msg.linear.z = vz
            self.velocity_pub.publish(vel_msg)

if __name__ == '__main__':
    try:
        node = KCFTrackerNode()
        rospy.spin()
    except rospy.ROSInterruptException:
        pass

请注意，此节点使用了pyimagesearch库中的CentroidTracker和TrackableObject类，您需要先安装此库：

pip install imutils

此外，这里的代码将图像中间作为目标点，将图像宽度的10％用作最小目标宽度，将真实世界中的实际宽度设置为0.5米。您可能需要根据您的具体应用程序进行一些修改。

将下列Python代码更正local_pos_pub3 = rospy.Publisher('mavros/setpoint_position/local', PoseStamped, queue_size=10) # poscom = PoseStamped() #消息类型PositionCommand() 改成PoseStamped() rate = rospy.Rate(20.0) i = 0 while not rospy.is_shutdown(): poscom.header.stamp = rospy.Time.now() poscom.header.frame_id = "world" poscom.pose.position.x = 2.5 * math.sin(math.pi * i / 400) poscom.pose.position.y = 5 * math.sin(math.pi * i / 800) poscom.pose.position.z = 2 poscom_twist = TwistStamped() poscom_twist.header.stamp = rospy.Time.now() poscom_twist.header.frame_id = "base_link" poscom_twist.twist.linear.x = 0 poscom_twist.twist.linear.y = 0 poscom_twist.twist.linear.z = 0 poscom_twist.twist.angular.x = 0 poscom_twist.twist.angular.y = 0 poscom_twist.twist.angular.z = 0 local_pos_pub3.publish(poscom) local_pos_pub4.publish(poscom_twist)

根据你的描述，需要将代码中的 `poscom = PositionCommand()` 改为 `poscom = PoseStamped()`，并且需要添加对 `local_pos_pub4` 的定义。下面是更正后的代码：

local_pos_pub3 = rospy.Publisher('mavros/setpoint_position/local', PoseStamped, queue_size=10)
local_pos_pub4 = rospy.Publisher('topic_name', TwistStamped, queue_size=10) # 定义 local_pos_pub4
poscom = PoseStamped() # 改为 PoseStamped()
rate = rospy.Rate(20.0)
i = 0

while not rospy.is_shutdown():
    poscom.header.stamp = rospy.Time.now()
    poscom.header.frame_id = "world"
    poscom.pose.position.x = 2.5 * math.sin(math.pi * i / 400)
    poscom.pose.position.y = 5 * math.sin(math.pi * i / 800)
    poscom.pose.position.z = 2

    poscom_twist = TwistStamped()
    poscom_twist.header.stamp = rospy.Time.now()
    poscom_twist.header.frame_id = "base_link"
    poscom_twist.twist.linear.x = 0
    poscom_twist.twist.linear.y = 0
    poscom_twist.twist.linear.z = 0
    poscom_twist.twist.angular.x = 0
    poscom_twist.twist.angular.y = 0
    poscom_twist.twist.angular.z = 0

    local_pos_pub3.publish(poscom)
    local_pos_pub4.publish(poscom_twist)
    
    i += 1
    rate.sleep()

注意，`local_pos_pub4` 的定义语句中的 `topic_name` 需要替换成实际的话题名称。