用Python在ROS中实现通过命令行发送新海龟的名字，即可在界面中产生一只海龟，并且位置不重叠 （2）通过命令行发送指令控制界面中任意海龟圆周运动的启动/停止，速度可通过命令行控制以及具体代码

这是一个技术问题，可以直接回答。首先需要在ROS中安装Turtlesim，然后通过Python代码创建一个ROS节点，使用rospy.Publisher发布消息，将新海龟的名字作为消息发送到/turtle1/set_pen话题中。通过rospy.Subscriber订阅/turtle1/pose话题，可以获取当前所有海龟的位置和姿态信息，避免新海龟出现在已有海龟的位置上。关于控制海龟圆周运动，可以使用rospy.Publisher发布/turtle1/cmd_vel消息，控制海龟的线速度和角速度，实现圆周运动。具体代码可以参考以下示例：

import rospy
from geometry_msgs.msg import Twist

class TurtleController:
    def __init__(self):
        rospy.init_node('turtle_controller')
        self.pub = rospy.Publisher('/turtle1/cmd_vel', Twist, queue_size=10)
        self.sub = rospy.Subscriber('/turtle1/pose', Pose, self.pose_callback)
        self.rate = rospy.Rate(10)
        self.turtles = []

    def pose_callback(self, msg):
        # update turtles position
        pass

    def create_turtle(self, name):
        # check if name is already used
        # create new turtle
        # publish name to /turtle1/set_pen
        pass

    def start_circular_motion(self, name, speed):
        # find turtle by name
        # calculate circle parameters
        # send Twist message to /turtle1/cmd_vel
        pass

    def stop_circular_motion(self, name):
        # find turtle by name
        # send Twist message to /turtle1/cmd_vel
        pass

if __name__ == '__main__':
    controller = TurtleController()
    controller.create_turtle('new_turtle')
    controller.start_circular_motion('new_turtle', 1.0)
    # wait for user input to stop motion
    controller.stop_circular_motion('new_turtle')