Instructions | ROS mobile robot

1

Preparing the base

First, you will need to cut the aluminium plate. The exact size depends on the motors - they need to fit in a way that will allow to connect the wires.
2

Adding the motors

The motors need to be attached at the bottom of a robot in a way, that will block them from moving or rotating. In this case it was done by screwing them to the base with some pipe holders.
3

Setting the control unit

Now you want to flip the robot back up. If your cover has two parts, you may want to attach one now like in this case. Next, screw / tape / glue the CORE2 and batteries to the robot.
4

Adding the lidar

Now we will be attaching the lidar. Make sure it is on the top of the robot. Doesn't really need to be in the middle due to the used software. I've screwed it to the top of the cover and drilled a hole in it for the wires.
5

The USB camera

Simply attach the USB camera to the front of the robot. I used tape.
6

Set up the software

You will need to connect to your CORE2. The detailed instruction is aviable at husarion.com. You will need to download hConfig to your mobile device and follow the instructions.
---------- more ----------https://husarion.com/core2/tutorials/ros-tutorials/1-ros-introduction/
7

Find the IP

If the CORE2 was registered succesfully, it should appear on the list at cloud.husarion.com. Click "Edit", then "More" and you should find the IP address we need to connect to the robot.
8

Connect to the RPi

You will need to have your PC connected to the same LAN network as your CORE2. Launch a program like Remote Desktop (may differ for diffrent systems) and connect to the IP you got from the previous step. The login and password should be "husarion" if they weren't changed.
9

Start ROS

Open the terminal and type "roscore". It will start ROS.

Upload the code for CORE2

At cloud.husarion.com start a new project and paste the following:

#include "hFramework.h"
#include "hCloudClient.h"
#include <stdio.h>
#include <iostream>
#include <ros.h>
#include "std_msgs/String.h"
#include "geometry_msgs/Twist.h"

using namespace hFramework;

bool batteryLow = false;

ros::NodeHandle nh;

void twistCallback(const geometry_msgs::Twist &twist)
{    float lin = twist.linear.x;    float ang = twist.angular.z;    float motorL = lin - ang * 0.5;    float motorR = lin + ang * 0.5;    hMot1.setPower(motorR * (-700) * !batteryLow);    hMot2.setPower(motorR * (-700) * !batteryLow);    hMot3.setPower(motorL * (-700) * !batteryLow);    hMot4.setPower(motorL * (-700) * !batteryLow);
}

void batteryCheck()
{    int i = 0;    for (;;) {        if (sys.getSupplyVoltage() > 11.1) {            i--;        } else {            i++;        }        if (i > 50) {            batteryLow = true;            i = 50;        }        if (i < -50) {            batteryLow = false;            i = -50;        }        if (batteryLow == true) {            LED1.toggle();        } else {            LED1.on();        }        sys.delay(250);    }
}

ros::Subscriber<geometry_msgs::Twist> sub("/cmd_vel", &twistCallback);

void hMain()
{    platform.begin(&RPi);    nh.getHardware()->initWithDevice(&platform.LocalSerial);    nh.initNode();    nh.subscribe(sub);    hMot3.setMotorPolarity(Polarity::Reversed);    hMot3.setEncoderPolarity(Polarity::Reversed);    hMot4.setMotorPolarity(Polarity::Reversed);    hMot4.setEncoderPolarity(Polarity::Reversed);    LED1.on();    sys.taskCreate(batteryCheck);    while (true)    {        nh.spinOnce();        sys.delay(100);    }
}


Code - the source
Now upload this project to the device.

ROS mobile robot

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