Connection closed by remote host

Pi Image
1

Hello,
I’m using ubiquity ROS image and PIGPIO to use GPIO, but when I try to use GPIO with rosrun etc., it shows “connection closed by remote host”. Please tell me the solution.
thanks

2

Hi Kota,

This message usually means that the Pi is turning off for some reason. Could you please post the code that you are running?

Rohan

3

Hi Rohan,
Thank you. This is the code.
#include
#include <pigpiod_if2.h>
#include <ros/ros.h>
#include <std_msgs/Int16MultiArray.h>

using std::abs;
using std::cout;
using std::endl;

constexpr int wheel_0_pin[3] = {17, 27, 22};
constexpr int wheel_1_pin[3] = {10, 9, 11};
constexpr int wheel_2_pin[3] = {5, 6, 13};
constexpr int wheel_3_pin[3] = {25, 8, 7};

int pwm_right_front, pwm_left_front, pwm_right_back, pwm_left_back;

class l298n {
private:
int gpio_handle;
int pwm_pin, change_pin1, change_pin2;
void front(int pwm);
void back(int pwm);

public:
l298n(int user_pwm_pin, int user_change_pin1, int user_change_pin2);
void set(int pwm);
};

l298n::l298n(int user_pwm_pin, int user_change_pin1, int user_change_pin2) {
pwm_pin = user_pwm_pin;
change_pin1 = user_change_pin1;
change_pin2 = user_change_pin2;
gpio_handle = pigpio_start(0, 0);
set_mode(gpio_handle, change_pin1, PI_OUTPUT);
set_mode(gpio_handle, change_pin2, PI_OUTPUT);
set_mode(gpio_handle, pwm_pin, PI_OUTPUT);
}

void l298n::set(int pwm) {
pwm >= 0 ? this->front(abs(pwm)) : this->back(abs(pwm));
}

void l298n::front(int pwm) {
gpio_write(gpio_handle, change_pin1, 1);
gpio_write(gpio_handle, change_pin2, 0);
set_PWM_dutycycle(gpio_handle, pwm_pin, pwm);
}

void l298n::back(int pwm) {
gpio_write(gpio_handle, change_pin1, 0);
gpio_write(gpio_handle, change_pin2, 1);
set_PWM_dutycycle(gpio_handle, pwm_pin, pwm);
}

void mdCallback(const std_msgs::Int16MultiArray &msg) {
pwm_right_front = msg.data[0];
pwm_left_front = msg.data[1];
pwm_right_back = msg.data[2];
pwm_left_back = msg.data[3];
}
int main(int argc, char **argv) {
cout << “start” << endl;
ros::init(argc, argv, “md_info”);
ros::NodeHandle n;
ros::Subscriber md_sub = n.subscribe(“wheel_info”, 10, mdCallback);
l298n right_front_wheel(wheel_0_pin[0], wheel_0_pin[1], wheel_0_pin[2]);
l298n left_front_wheel(wheel_1_pin[0], wheel_1_pin[1], wheel_1_pin[2]);
l298n right_back_wheel(wheel_2_pin[0], wheel_2_pin[1], wheel_2_pin[2]);
l298n left_back_wheel(wheel_3_pin[0], wheel_3_pin[1], wheel_3_pin[2]);
cout << “create object” << endl;
ros::Rate loop_rate(1000);
while (ros::ok()) {
cout << “in loop” << endl;
right_front_wheel.set(pwm_right_front);
left_front_wheel.set(pwm_left_front);
right_back_wheel.set(pwm_right_back);
left_back_wheel.set(pwm_left_back);
ros::spinOnce();
loop_rate.sleep();
}
}

4

Try removing the ubiquity-leds-buttons from your /boot/config.txt there may be an issue with conflicting GPIO assignments.

Barring that, make sure that your power supply to the Pi is good. Looks like you are turning motors, this may be causing your power supply to dip, and the Pi to shutdown.