My robot moves forward, but does not turn

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Hello, I have managed to make my robot move, but when it reaches a wall, it stops a little before and does not turn. Instead, it makes braking movement but nothing more.

#include "geometry_msgs/Twist.h"
#include "ros/init.h"
#include "ros/node_handle.h"
#include "ros/publisher.h"
#include <algorithm>
#include <array>
#include <boost/type_traits/integral_constant.hpp>
#include <float.h>
#include <iostream>
#include <ros/ros.h>
#include <sensor_msgs/LaserScan.h>
#include <stdint.h>

float minF, minI, minD;
float matrizD[250];
float matrizF[220];
float matrizI[250];

void funct(const sensor_msgs::LaserScan::ConstPtr &msg) {
  int j = 0;
  float val;
  for (int i = 0; i < 720; i++) {
    if (std::isinf(msg->ranges[i])) {
      val = msg->range_max;
    } else {
      val = msg->ranges[i];
      val = (float)val;
    }
    if (i < 120) {
      matrizD[i] = val;
    }
    if ((i >= 120) && (i < 660)) {
      j = i - 120;
      matrizF[j] = val;
    }
    if ((i >= 600) && (i < 720)) {
      j = i - 600;
      matrizD[j] = val;
    }
  }
  minF = float(*std::min_element(std::begin(matrizF), std::end(matrizF)));
  minD = float(*std::min_element(std::begin(matrizD), std::end(matrizD)));
  minI = float(*std::min_element(std::begin(matrizI), std::end(matrizI)));
  std::printf("%f - %f - %f",minI,minF, minD);
}

int main(int argc, char **argv) {
  ros::init(argc, argv, "topics_quiz_node");
  ros::NodeHandle robot;
  ros::Publisher vel_pub =
      robot.advertise<geometry_msgs::Twist>("/cmd_vel", 100);
  ros::Subscriber laser_sub = robot.subscribe("/kobuki/laser/scan", 10, funct);
  while (true) {
    geometry_msgs::Twist msg;
    sensor_msgs::LaserScan lsr;
    msg.linear.x = 0;
    msg.angular.x = 0;
    msg.linear.y = 0;
    msg.linear.z = 0;
    msg.angular.y = 0;
    msg.angular.z = 0;
    std::cout << "Mínimo Iz: " << minI  << std::endl;
    std::cout << "Mínimo Fr: " << minF  << std::endl;
    std::cout << "Mínimo De: " << minD  << std::endl;
    if (minF >= 0.7) {
      // Avanza al frente
      msg.linear.x = 0.1;
      msg.angular.x = 0;
    } else { 
      msg.linear.x = 0;
      msg.angular.x = 10.0;
    }
    if ((minI < 0.5)&& (minF <= 0.5)){
      // Gira a la izquierda
      msg.linear.x = 0;
      msg.angular.x = -10.0;
    }
    if ((minD < 0.5)&& (minF <= 0.5)) {
      // Gira a la derecha
      msg.linear.x = 0;
      msg.angular.x = 10.0;
    }
    ros::spinOnce();
    vel_pub.publish(msg);
  }
  return 0;
}

I must have something wrong. It stops and does nothing. It doesn't crash, but it doesn't move, either. It doesn't even turn!

I program the robot on the www.theconstructsim.com platform.

Thanks a lot