写了倒车的程序却无法运行

wanghao

#!/usr/bin/env python
# coding=utf-8

import rospy
from geometry_msgs.msg import Twist
from nav_msgs.msg import Odometry

class ReverseParkingController:
    def __init__(self):
        rospy.init_node('reverse_parking_controller')
        rospy.on_shutdown(self.shutdown)

        self.reverse_distance = 0.0
        self.reverse_mileage = 0.0
        self.odom_received = False

        self.odom_sub = rospy.Subscriber('/odom', Odometry, self.odom_callback)
        self.cmd_vel_pub = rospy.Publisher('/cmd_vel', Twist, queue_size=10)

    def odom_callback(self, odom):
        if not self.odom_received:
            self.odom_received = True

        # 假设车辆的行驶方向与x轴平行，只关注x轴上的位移变化
        delta_distance = odom.pose.pose.position.x - self.reverse_distance
        self.reverse_distance = odom.pose.pose.position.x

        # 更新倒车里程信息
        if delta_distance < 0:
            self.reverse_mileage += abs(delta_distance)

    def reverse_parking(self, distance):
        rate = rospy.Rate(10)  # 控制频率为10Hz
        cmd_vel = Twist()

        # 设置线速度和角速度，让车辆后退
        cmd_vel.linear.x = -0.2  # 假设线速度为-0.2m/s
        cmd_vel.angular.z = 0.0

        # 循环发布速度指令直到达到倒车距离
        while not rospy.is_shutdown():
            if self.odom_received and self.reverse_distance > distance:
                self.cmd_vel_pub.publish(cmd_vel)
            else:
                break
            rate.sleep()

        # 发布停止指令
        cmd_vel.linear.x = 0.0
        self.cmd_vel_pub.publish(cmd_vel)

        rospy.loginfo('Reverse parking complete. Reverse distance: %.2f meters', self.reverse_distance)
        rospy.loginfo('Reverse mileage: %.2f meters', self.reverse_mileage)

    def shutdown(self):
        rospy.loginfo('Shutting down reverse parking controller...')
        cmd_vel = Twist()
        cmd_vel.linear.x = 0.0
        self.cmd_vel_pub.publish(cmd_vel)
        rospy.sleep(1)

if __name__ == '__main__':
    try:
        controller = ReverseParkingController()
        controller.reverse_parking(5.0)  # 设置倒车距离为5.0米
    except rospy.ROSInterruptException:
        pass

终端没有报错，也在launch文件里打开了底盘，但是启动后没有任何反应