基于ROS和python，通过TCP通信协议，完成键盘无线控制移动机器人运动

2022-03-19 12:01:57

一、所需工具包

1.ROS键盘包：teleop_twist_keyboard

2.TCP通讯包：socket

$ cd ~/catkin_ws/src
$ git clone https://github.com/Forrest-Z/teleop_twist_keyboard.git
$ catkin_make

3.在ubuntu的ros中建立一个ros_car_py包:

$ cd ~/catkin_ws/src
$ catkin_create_pkg ros_car_py roscpp rospy std_msgs

4.新建 base 文件:

$ cd catkin_ws/src/base
$ mkdir src
$ vim src/base.py

代码如下(ROS作为TCP服务器):

    #!/usr/bin/env python

    # coding=utf-8

    import rospy

    from socket import *

    import time

    from threading import Thread

    from std_msgs.msg import String

    from geometry_msgs.msg import Twist

    msg_list = []

    def callback(cmd_input, Socket):

        print("-----服务器已经启动成功，准备接收数据-----")

        Socket.settimeout(5)

        recvdata = Socket.recv(4096)

        t = Twist()

        t.angular.z = cmd_input.angular.z

        t.linear.x = cmd_input.linear.x

        left_speed = t.linear.x - t.angular.z * 0.5 * 0.2

        right_speed = t.linear.x + t.angular.z * 0.5 * 0.2

        left_speed *= 1000

        right_speed *= 1000

        left_speed = str(left_speed)

        right_speed = str(right_speed)

        # msg_list.append(left_speed)

        # msg_list.append(right_speed)

        print("left_speed=%s" % left_speed)

        print("right_speed=%s" % right_speed)

        if len(recvdata) != 0:

        　　print("-----接收到数据-----")

        　　print("recvdata:%s" % recvdata)

       　　 # Socket.send(b"hello beaglebone")

       　　 # Socket.send(b"左轮速度")

       　　 Socket.send(left_speed.encode("utf-8"))

        　　# Socket.send(b"右轮速度")

        　　Socket.send(right_speed.encode("utf-8"))

        　　# Socket.send(msg_list)

        else:

        　　print('-----未接收到客户端数据，可能连接已经断开-----')

        　　# Socket.send(b'client off')

        　　# 数据中断时进行服务重启程序，先close 再accept等待重新连线

        　　# 可以防止出现当client意外终止导致server的中断（Broken pipe错误）

       　　 print('-----正在重新建立连接-----')

       　　 Socket.close()

        Socket, clientInfo = serverSocket.accept()

        # serverSocket.close()

    def main():

        rospy.init_node("base")

        serverSocket = socket(AF_INET, SOCK_STREAM)

        serverSocket.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1)

        serverSocket.bind(('', 8899))

        serverSocket.listen(5)

        print("-----服务器正在启动-----")

        Socket, clientInfo = serverSocket.accept()

        sub = rospy.Subscriber("cmd_vel", Twist, callback, Socket)

        rate = rospy.Rate(10)

        rospy.spin()

    if __name__ == "__main__":

        main()

注意事项:

ROS中的python是python2,使用python3会出错，所以需要在开头加上#!/usr/bin/env python
编写好python程序后，编译成功但是无法运行，报错Couldn't find executable named XXX.py，无法执行
问题原因:
文件没有执行权限
解决办法:
给文件添加执行权限
命令：chmod +x base.py

修改CMakeList.txt:

cmake_minimum_required(VERSION 2.8.3)
project(ros_car_py)
find_package(catkin REQUIRED COMPONENTS
roscpp
rospy
std_msgs
message_generation
)
add_message_files(
FILES
MsgCar.msg
)
generate_messages(
DEPENDENCIES
std_msgs
)
catkin_package(
# INCLUDE_DIRS include
# LIBRARIES ros_car_py
CATKIN_DEPENDS message_runtime
#roscpp rospy std_msgs
# DEPENDS system_lib
)
include_directories(
# include
${catkin_INCLUDE_DIRS}
)

单独编译ros_car_pkg包:

$ catkin_make -DCATKIN_WHITELIST_PACKAGES='ros_car_py'

二、控制原理：

当我们按下键盘时，teleop_twist_keyboard 包会发布 /cmd_vel 发布速度主题
在 base 节点订阅这个话题，接收速度数据，转换成字符串(TCP只允许发送字符串)，然后发送至客户端

设置beaglebone作为客户端：

运行代码加载设备树并读串口数据用于控制PWM，进而控制小车运动

    from socket import *

    import time

    SLOTS = "/sys/devices/bone_capemgr.9/slots"

    p1_duty = "/sys/devices/ocp.3/pwm_test_P9_16.16/duty"

    p2_duty = "/sys/devices/ocp.3/pwm_test_P8_13.15/duty"

    p1_period = "/sys/devices/ocp.3/pwm_test_P9_16.16/period"

    p2_period = "/sys/devices/ocp.3/pwm_test_P8_13.15/period"

    p1_run = "/sys/devices/ocp.3/pwm_test_P9_16.16/run"

    p2_run = "/sys/devices/ocp.3/pwm_test_P8_13.15/run"

    p1_export = "/sys/class/gpio/export"

    p2_export = "/sys/class/gpio/export"

    p1_direction = "/sys/class/gpio/gpio44/direction"

    p2_direction = "/sys/class/gpio/gpio45/direction"

    p1_polarity = "/sys/class/gpio/gpio44/value"

    p2_polarity = "/sys/class/gpio/gpio45/value"

    msg_lists = []

    clientSocket = socket(AF_INET, SOCK_STREAM)

    clientSocket.connect(("192.168.1.151", 8899))

    try:

        with open(SLOTS, "a") as f:

       　　 f.write("am33xx_pwm")

        with open(SLOTS, "a") as f:

        　　f.write("bone_pwm_P9_22")

        with open(SLOTS, "a") as f:

        　　f.write("bone_pwm_P9_16")

        with open(p1_export, "a") as f:

       　　 f.write("44")

        with open(p2_export, "a") as f:

       　　 f.write("45")

        with open(p1_direction, "a") as f:

        　　f.write("in")

        with open(p2_direction, "a") as f:

       　　 f.write("in")

    except:

        pass

    while True:

        clientSocket.send(b"hello ROS")

        msg_list1 = clientSocket.recv(1024)

        msg_list2 = clientSocket.recv(1024)

        if len(msg_list1) or len(msg_list2) > 0:

        msg_lists.append(msg_list1)

        msg_lists.append(msg_list2)

        for msg in msg_lists:

            print("recvData:%s" % msg)

        if msg_lists[0] == '500.0' and msg_lists[1] == '500.0':

            msg_lists = []

            print("succes")

            try:

                with open(p1_period, "a") as f:

                    f.write("500000")

                with open(p1_duty, "a") as f:

                    f.write("250000")

                with open(p2_period, "a") as f:

                    f.write("500000")

                with open(p2_duty, "a") as f:

                    f.write("250000")

                with open(p1_run, "a") as f:

                    f.write("1")

                with open(p2_run, "a") as f:

                    f.write("1")

                with open(p1_polarity, "a") as f:

                    f.write("1")

                with open(p2_polarity, "a") as f:

                    f.write("1")

            except:

                pass

        elif msg_lists[0] == '400.0' and msg_lists[1] == '600.0':

            msg_lists = []

            try:

                with open(p1_period, "a") as f:

                    f.write("400000")

                with open(p1_duty, "a") as f:

                    f.write("200000")

                with open(p2_period, "a") as f:

                    f.write("600000")

                with open(p2_duty, "a") as f:

                    f.write("300000")

                with open(p1_run, "a") as f:

                    f.write("1")

                with open(p2_run, "a") as f:

                    f.write("1")

                with open(p1_polarity, "a") as f:

                    f.write("1")

                with open(p2_polarity, "a") as f:

                    f.write("1")

            except:

                pass

        elif msg_lists[0] == '600.0' and msg_lists[1] == '400.0':

            msg_lists = []

            try:

                with open(p1_period, "a") as f:

                    f.write("600000")

                with open(p1_duty, "a") as f:

                    f.write("300000")

                with open(p2_period, "a") as f:

                    f.write("400000")

                with open(p2_duty, "a") as f:

                    f.write("200000")

                with open(p1_run, "a") as f:

                    f.write("1")

                with open(p2_run, "a") as f:

                    f.write("1")

                with open(p1_polarity, "a") as f:

                    f.write("1")

                with open(p2_polarity, "a") as f:

                    f.write("1")

            except:

                pass

        elif msg_lists[0] == '-500.0' and msg_lists[1] == '-500.0':

            msg_lists = []

            try:

                with open(p1_period, "a") as f:

                    f.write("500000")

                with open(p1_duty, "a") as f:

                    f.write("250000")

                with open(p2_period, "a") as f:

                    f.write("500000")

                with open(p2_duty, "a") as f:

                    f.write("250000")

                with open(p1_run, "a") as f:

                    f.write("1")

                with open(p2_run, "a") as f:

                    f.write("1")

                with open(p1_polarity, "a") as f:

                    f.write("0")

                with open(p2_polarity, "a") as f:

                    f.write("0")

            except:

                pass

        elif msg_lists[0] == '-600.0' and msg_lists[1] == '-400.0':

            msg_lists = []

            try:

                with open(p1_period, "a") as f:

                    f.write("600000")

                with open(p1_duty, "a") as f:

                    f.write("300000")

                with open(p2_period, "a") as f:

                    f.write("400000")

                with open(p2_duty, "a") as f:

                    f.write("200000")

                with open(p1_run, "a") as f:

                    f.write("1")

                with open(p2_run, "a") as f:

                    f.write("1")

                with open(p1_polarity, "a") as f:

                    f.write("0")

                with open(p2_polarity, "a") as f:

                    f.write("0")

            except:

                pass

        elif msg_lists[0] == '-400.0' and msg_lists[1] == '-600.0':

            msg_lists = []

            try:

                with open(p1_period, "a") as f:

                    f.write("400000")

                with open(p1_duty, "a") as f:

                    f.write("200000")

                with open(p2_period, "a") as f:

                    f.write("600000")

                with open(p2_duty, "a") as f:

                    f.write("300000")

                with open(p1_run, "a") as f:

                    f.write("1")

                with open(p2_run, "a") as f:

                    f.write("1")

                with open(p1_polarity, "a") as f:

                    f.write("0")

                with open(p2_polarity, "a") as f:

                    f.write("0")

            except:

                pass

        elif msg_lists[0] == '0.0' and msg_lists[1] == '0.0':

            msg_lists = []

            try:

                with open(p1_run, "a") as f:

                    f.write("0")

                with open(p2_run, "a") as f:

                    f.write("0")

            except:

                pass

        else:

            pass

        else:

        time.sleep(0.1)

        clientSocket = socket(AF_INET, SOCK_STREAM)

        clientSocket.connect(("192.168.1.138", 8899))

码农公寓

一、所需工具包

1.ROS键盘包：teleop_twist_keyboard

2.TCP通讯包：socket

3.在ubuntu的ros中建立一个ros_car_py包:

4.新建 base 文件:

代码如下(ROS作为TCP服务器):

注意事项:

修改CMakeList.txt:

单独编译ros_car_pkg包:

二、控制原理：

设置beaglebone作为客户端：

运行代码加载设备树并读串口数据用于控制PWM，进而控制小车运动

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