编写一个actionsever和一个actionclient的python代码使得小车朝着目标位置运动

好的，这里是一个简单的实现示例，使用ROS中的Python API：

## Action Server Code

#!/usr/bin/env python

import rospy
import actionlib

from move_base_msgs.msg import MoveBaseAction, MoveBaseGoal

class MoveBaseServer:
    def __init__(self):
        self.server = actionlib.SimpleActionServer('move_base', MoveBaseAction, self.execute, False)
        self.server.start()
        
    def execute(self, goal):
        rospy.loginfo('Received goal: %s', goal)
        # Extract coordinates from goal
        x, y = goal.target_pose.pose.position.x, goal.target_pose.pose.position.y
        # Set up move_base goal
        mb_goal = MoveBaseGoal()
        mb_goal.target_pose.header.frame_id = 'map'
        mb_goal.target_pose.pose.position.x = x
        mb_goal.target_pose.pose.position.y = y
        mb_goal.target_pose.pose.orientation.w = 1.0
        # Send goal to move_base
        mb_client = actionlib.SimpleActionClient('move_base', MoveBaseAction)
        mb_client.wait_for_server()
        mb_client.send_goal(mb_goal)
        mb_client.wait_for_result()
        # Return result status to client
        result = mb_client.get_state()
        self.server.set_succeeded(result)

if __name__ == '__main__':
    rospy.init_node('move_base_server')
    server = MoveBaseServer()
    rospy.spin()

## Action Client Code

#!/usr/bin/env python

import rospy
import actionlib

from move_base_msgs.msg import MoveBaseAction, MoveBaseGoal

class MoveBaseClient:
    def __init__(self):
        self.client = actionlib.SimpleActionClient('move_base', MoveBaseAction)
        self.client.wait_for_server()
        
    def move_to_goal(self, x, y):
        goal = MoveBaseGoal()
        goal.target_pose.header.frame_id = 'map'
        goal.target_pose.pose.position.x = x
        goal.target_pose.pose.position.y = y
        goal.target_pose.pose.orientation.w = 1.0
        self.client.send_goal(goal)
        self.client.wait_for_result()
        result = self.client.get_state()
        return result

if __name__ == '__main__':
    rospy.init_node('move_base_client')
    client = MoveBaseClient()
    # Example usage: move to (1, 2)
    client.move_to_goal(1, 2)

这里我们使用了ROS的move_base包来实现小车的移动，Action Server接收到目标位置后，将目标位置传递给move_base，Action Client发送目标位置给Action Server，等待Action Server执行完毕后返回执行状态。注意：需要在ROS中启动move_base节点和相关的底盘驱动节点。