写一个键盘控制小车底盘运动的ROS节点的C++代码

以下是一个简单的键盘控制小车底盘运动的ROS节点的C++代码，它可以接收键盘上的方向键控制小车的运动方向：

#include <ros/ros.h>
#include <geometry_msgs/Twist.h>
#include <stdio.h>
#include <termios.h>
#include <unistd.h>
#include <fcntl.h>

int kfd = 0;
struct termios cooked, raw;

int getch(void)
{
    int c = 0;
    tcgetattr(kfd, &cooked);
    memcpy(&raw, &cooked, sizeof(struct termios));
    raw.c_lflag &= ~(ICANON | ECHO);
    raw.c_cc[VEOL] = 1;
    raw.c_cc[VEOF] = 2;
    tcsetattr(kfd, TCSANOW, &raw);
    setbuf(stdin, NULL);
    c = getchar();
    tcsetattr(kfd, TCSANOW, &cooked);
    return c;
}

int main(int argc, char** argv)
{
    ros::init(argc, argv, "keyboard_control");
    ros::NodeHandle nh;
    ros::Publisher pub = nh.advertise<geometry_msgs::Twist>("cmd_vel", 100);

    float speed = 0.5;
    float turn = 1.0;
    float x = 0.0;
    float y = 0.0;
    float z = 0.0;

    while(ros::ok()) {
        int c = getch();
        switch(c) {
            case 'w':
                x = speed;
                y = 0;
                z = 0;
                break;
            case 'a':
                x = 0;
                y = speed;
                z = 0;
                break;
            case 's':
                x = -speed;
                y = 0;
                z = 0;
                break;
            case 'd':
                x = 0;
                y = -speed;
                z = 0;
                break;
            case 'q':
                x = 0;
                y = 0;
                z = turn;
                break;
            case 'e':
                x = 0;
                y = 0;
                z = -turn;
                break;
            default:
                x = 0;
                y = 0;
                z = 0;
                break;
        }

        geometry_msgs::Twist msg;
        msg.linear.x = x;
        msg.linear.y = y;
        msg.linear.z = 0;
        msg.angular.x = 0;
        msg.angular.y = 0;
        msg.angular.z = z;

        pub.publish(msg);
    }

    return 0;
}

这个节点订阅了名为“cmd_vel”的主题，并在接收到键盘输入后将消息发布到该主题上，控制小车的运动。