直播课遇到点小bug，没有弄好，现在已经ok。
蓝桥ROS机器人之turtlesim贪吃蛇
这里案例只是为了说明，算法不分系统，全平台支持的！
愿意花时间所有linux案例都能移植到win10/11，主要是时间太紧张了……无奈，有时候也没必要移植。
课程中截图如下：
还测试了一个movetogoal
坚持写博客，也是鼓励学生写，自己怎么能不写。
如果我做不到如何要求学生做？
要求从我第一次上课就提了，7年过去了，效果很惨淡啊，多惨淡呢？
每学期课程都会提及这个要求，但印象中，真正写的学生不到10人，但是！
但是，但是！
这10人当中，有9人是之前自己就写博客的。
响应的学生太少了……
也论证了如下结果：
www.zhihu.com/question/520747377/answer/2449718139
里面重要的一句话：
我原本一直觉得师生对于课程结果的重要性是对半分的，各50%。
7年工作经历下来，教师作用说有10%都很夸张，当然也没有1%那么低。
一些群聊及主动学习或者交流，多有如下情况：
import rospy
from tanksim.msg import Pose
from tanksim.srv import Spawn
from tanksim.srv import SetPen
from geometry_msgs.msg import Twist
from geometry_msgs.msg import TransformStamped
import random
import math
tank1_pose = Pose()
tanklist = []
lasttank = 1
nexttankIndex = 1
class mySpawner:
def __init__(self, tname):
self.tank_name = tname
self.state = 1
rospy.wait_for_service('/spawn')
try:
client = rospy.ServiceProxy('/spawn', Spawn)
x = random.randint(1, 10)
y = random.randint(1, 10)
theta = random.uniform(1, 3.14)
name = tname
_nm = client(x, y, theta, name)
rospy.loginfo("tank Created [%s] [%f] [%f]", name, x, y)
rospy.Subscriber(self.tank_name '/pose', Pose, self.tank_poseCallback)
self.pub = rospy.Publisher(self.tank_name '/cmd_vel', Twist, queue_size=10)
self.tank_to_follow = 1
self.tank_pose = Pose()
rospy.wait_for_service("/" tname '/set_pen')
try:
client = rospy.ServiceProxy("/" tname '/set_pen', SetPen)
client(0,0,0,0,1)
except rospy.ServiceException as e:
print("Service call failed: %s"%e)
except rospy.ServiceException as e:
print("Service tp spawn a tank failed. %s", e)
def tank_poseCallback(self, data):
self.tank_pose = data
def tank_velocity(self, msg):
self.pub.publish(msg)
def tank1_poseCallback(data):
global tank1_pose
global lasttank
global tanklist
global nexttankIndex
tank1_pose.x = round(data.x, 4)
tank1_pose.y = round(data.y, 4)
tank1_pose.theta = round(data.theta, 4)
for i in range(len(tanklist)):
twist_data = Twist()
diff = math.sqrt(pow((tank1_pose.x - tanklist[i].tank_pose.x) , 2) pow((tank1_pose.y - tanklist[i].tank_pose.y), 2))
ang = math.atan2(tank1_pose.y - tanklist[i].tank_pose.y, tank1_pose.x - tanklist[i].tank_pose.x) - tanklist[i].tank_pose.theta
if(ang <= -3.14) or (ang > 3.14):
ang = ang / math.pi
if (tanklist[i].state == 1):
if diff < 1.0:
tanklist[i].state = 2
tanklist[i].tank_to_follow = lasttank
lasttank = i 2
rospy.loginfo("tank Changed [%s] [%f] [%f]", tanklist[i].tank_name, diff, ang)
nexttankIndex = 1
tanklist.append(mySpawner("tank" str(nexttankIndex)))
else:
parPose = tank1_pose
if(tanklist[i].tank_to_follow != 1):
parPose = tanklist[tanklist[i].tank_to_follow - 2].tank_pose
diff = math.sqrt(pow((parPose.x - tanklist[i].tank_pose.x) , 2) pow((parPose.y - tanklist[i].tank_pose.y), 2))
goal = math.atan2(parPose.y - tanklist[i].tank_pose.y, parPose.x - tanklist[i].tank_pose.x)
ang = math.atan2(math.sin(goal - tanklist[i].tank_pose.theta), math.cos(goal - tanklist[i].tank_pose.theta))
if(ang <= -3.14) or (ang > 3.14):
ang = ang / (2*math.pi)
if(diff < 0.8):
twist_data.linear.x = 0
twist_data.angular.z = 0
else:
twist_data.linear.x = 2.5 * diff
twist_data.angular.z = 20 * ang
tanklist[i].tank_velocity(twist_data)
tanklist[i].oldAngle = ang
def spawn_tank_fn():
global nexttankIndex
rospy.init_node('snake_tank', anonymous=True)
rospy.Subscriber('/tank1/pose', Pose, tank1_poseCallback)
rospy.wait_for_service("/tank1/set_pen")
try:
client = rospy.ServiceProxy('/tank1/set_pen', SetPen)
client(0,0,0,0,1)
except rospy.ServiceException as e:
print("Service call failed: %s"%e)
nexttankIndex = 1
tanklist.append(mySpawner("tank" str(nexttankIndex)))
# for i in range(2,10):
# tanklist.append(mySpawner("tank" str(i)))
rospy.spin()
if __name__ == "__main__":
spawn_tank_fn()
