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ROSbot ( 2 | 2 PRO | 2R )

Overview

ROSbot is a ROS powered 4x4 drive autonomous mobile robot platform equipped with LIDAR, RGB-D camera, IMU, encoders, distance sensors available in three version: "2" and "2 PRO" and "2R".

ROSbot is an affordable robot platform for rapid development of autonomous robots. It can be a base for custom service robots, inspection robots and robots working in swarms. All versions integrates:

  • 4-wheels mobile platform containing DC motors with encoders and an aluminum frame
  • Orbbec Astra RGBD camera
  • MPU 9250 inertial sensor or BNO055 (accelerometer + gyro)
  • rear panel providing interfaces for additional modules

ROSbot versions

ROSbot is available in three options which, next to features mentioned before, also include:

  • Raspberry Pi 4 with Broadcom BCM2711 (ARM64 architecture) quad-core ARM-8 Cortex-A72 1.5 GHz, 4GB RAM and 32 GB MicroSD.
  • RPLIDAR A2 laser scanner

ROSbot 2 is discontinued, but you can get its new generation - ROSbot 2R - available here.

Gazebo Simulation Model

You can also test the performance of ROSbot using our simulation model in Gazebo environment. It is available here, at our GitHub page.

ROSbot gazebo

You can find free ROS tutorials dedicated for ROSbot under this link. They will guide you through different aspects of programming autonomous vehicles in ROS

Hardware guide

Specification

ROSbot dimenstionsROSbot dimenstions
AttributeDescription
Dimensions with camera and LiDAR200 x 235 x 220mm / 7.87 x 9.25 x 8.66in [L x W x H]
Dimensions without camera200 x 235 x 146mm / 7.87 x 9.25 x 5.74in [L x W x H]
Dimensions without camera and LiDAR200 x 235 x 106mm / 7.87 x 9.25 x 4.17in [L x W x H]
Weight2,84kg / 100oz (with camera and LiDAR), 2,45kg / 86oz (without camera and LiDAR)
Standard wheel diameter / Clearance / Wheelbase85mm / 24.5mm / 105mm
Mecanum wheel diameter / Clearance / Wheelbase97mm / 30.6mm / 105mm
Chassis materialPowder-coated aluminum plate, 1.5mm thick
Maximum translational velocity1.0 m/s
Maximum rotational velocity420 deg/s (7.33 rad/s)
Maximum load capacityUp to 5kg / 176oz *not in continuous work
Battery life1.5h - 5h

Components

Scheme 2RScheme 2R

Components description

ComponentQuantityDescription
Infrared distance sensor4VL53L0X Time-of-Flight distance sensor with up to 200 cm range, more details
CORE21Real-time controller based on STM32F407 microcontroller.
DC motor4Xinhe Motor XH-25D, Motor used: RF-370, 6VDC nominal, 5000rpm, no load speed at the output shaft: 165 rpm, stall torque: 2.9 kg*cm, stall current: 2.2A, gear ratio: ~34 (exact ratio is 30613/900), encoder: magnetic, 48ppr, 12 poles
RGBD camera1Orbbec Astra with RGB image size 640x480 and depth image size 640x480.
Batteries3Li-Ion 18650 protected, rechargeable batteries, 3500mAh capacity, 3.7V nominal voltage. Note: Device may be shipped interchangeably with similar batteries.
Antenna1Connected directly to the ASUS Tinker Board Wi-Fi module. Uses an RP-SMA(m) <-> I-PEX MHF4 cable to connect the antenna with SBC.
ComponentQuantityDescription
SBC1Raspberry Pi 4 with Broadcom BCM2711 (ARM64 architecture) quad-core ARM-8 Cortex-A72 1.5 GHz, 4GB RAM and 32 GB MicroSD.. The SBC runs on Ubuntu-based OS, customized to use ROS.
LIDAR1RpLidar A2, 360 degree and up to 12m range, more details
IMU sensor1Intelligent 9-axis absolute orientation sensor BNO055, more details

Block diagram

Graphic representation of ROSbot 2R components and connections between them.

Block diagramBlock diagram

Rear panel description

Rear panel description

ComponentQuantityDescription
Antenna connector1Wi-Fi antenna RP-SMA socket - required for Wi-Fi connectivity
USB2USB 2.0 host ports from SBC
HDMI1HDMI output from SBC
Power switch1Turns ROSbot completely ON or OFF
LEDs6LR1(blue), LR2(yellow), L1(red), L2(green), L3(green), PWR(red), more details here
Reset button1Button used for reset CORE2
hBtn2hBtn1, hBtn2 - programmable buttons
Outputs for servo6Servo output with PWM, more details here
USB serial1USB serial port used for debugging the firmware on CORE2-ROS controller
Charging connector16-pin connector for charging internal Li-Ion batteries
DC power input1DC for working with external 12V power supply - use the power supply included with charger or any 12V, min. 5A power supply with 5.5/2.5mm plug (center-positive)
Time-of-Flight distance sensor2VL53L0X Time-of-Flight distance sensor with up to 200 cm range, more details here
hExt112xGPIO, 7x ADC, SPI, I2C, UART, more details here
hSens14 xGPIO, ADC, UART, more details here

Power supply

ROSbot is powered from an internal, rechargeable Li-Ion battery pack that contains 3 Li-Ion cells, connected in series. This type of connection is called “3S”. The schematic below explains how the cells are wired together and with the charging connector (on ROSbot side).

Batt connectionBatt connection

The BAT+ and BAT- are the power connections and the “bal Bxx” wires are used to monitor the voltage on each cell. It is strongly recommended to keep equal voltages on each cell during the charging process. The charger included with ROSbot can charge batteries in the described way and, thanks to that, the long life of the battery set is possible.

The nominal voltage of each cell is 3.7V but the useful range is 3.2V to 4.2V.

Important - discharge indicator If only the right firmware is preloaded to the internal controller (CORE2), the LED1 is programmed to indicate the power status:

  • the LED1 is on when the robot is turned on
  • the LED1 is blinking when battery is low – please charge immediately!

Please make sure that the user firmware always contains the function that monitors the supply voltage level. Deep discharging of batteries may decrease their lifecycle. Discharging to the voltage lower than 3.0V/cell can also trigger the over discharge protection. If the voltage is too low, turn ROSbot off and charge batteries as soon as possible.

Charging ROSbot

Charger+cables+PSUCharger+cables+PSU

The ROSbot kit contains the Redox Beta charger. It is an universal charger, suitable for charging NiCd, NiMH, Li-Po, Li-Fe, Li-Ion and Pb (AGM, VRLA) batteries. ROSbot shall be charged using an included charger and cable.

Charger kit includes:

  • Redox Beta charger
  • AC/DC power adapter 100...240V to 12V 5A with 5.5/2.5mm plug on the 12V side
  • a cable to connect charger with ROSbot charging port

Quick charging guide:

  1. Connect the power adapter to the charger and the output cable between charger and ROSbot (2 connectors on charger side, 1 black connector to ROSbot charging port).
  2. Use red and blue buttons to select “LiPo BATT” mode and press [Start].
  3. Use arrows to select “LiPo CHARGE” mode.
  4. Press [Start] - the current value should start blinking. Use arrows to set the current to 1.5A.
  5. Press [Start] again - the voltage value should start blinking. Select “11.1V(3S)” using arrows. The picture below shows the desired result.
  6. Press and hold [Start] for 2 seconds. The charger should now ask for confirmation. Press [Start] again. The charging process should begin now.
  7. When the charging will be finished (after about 3 hours), the charger will generate a loud “beep” sound and will finish charging at the same time.

Charge config

If you need more information about charging, please read the Charging manual for ROSbot in PDF format.

Notes

  • You can change charging current to maximum 3A. Please note that a regular charging with the maximum current can shorten the battery life.
  • If you are going to use ROSbot stationary for a long time, you can use ROSbot with charger or power supply connected all the time. Please see the Charging manual for ROSbot for details.
  • In case you need to replace batteries, use only 18650 Li-Ion batteries, with the capacity in a range of 1800...3500mAh and with a protection circuit! Using unprotected batteries may result in serious injuries or fire.
  • Unplug charging connectors carefully. You shall not unplug the charger connectors holding the wires. The balancer connection on ROSbot side has a latching tab (see photo below) that must be pressed before unplugging. On the charger side there is no latching tab but you should also unplug this connector holding the white plug.
Charger connectorCharger connector

Software

Software for ROSbot can be divided into 2 parts:

  • A low-level firmware that works on the real-time controller (CORE2). It can be developed using Visual Studio Code IDE.
  • OS based on Ubuntu 18.04 or 20.04, which runs on the SBC (ASUS Tinker Board, UP Board or Raspberry Pi 4) and contains all components needed to start working with ROS or ROS2 immediately. The microSD card or MMC memory with OS is included with each ROSbot. The OS has been modified to make the file system insensitive to sudden power cuts.

ROS API

Below are topics and services available in ROSbot:

TopicMessage typeDirectionNode          Description          
/mpu9250rosbot_ekf/Imupublisher/serial_nodeRaw IMU data in custom message type
/range/flsensor_msgs/Rangepublisher/serial_nodeFront left range sensor raw data
/range/frsensor_msgs/Rangepublisher/serial_nodeFront right range sensor raw data
/range/rlsensor_msgs/Rangepublisher/serial_nodeRear left range sensor raw data
/range/rrsensor_msgs/Rangepublisher/serial_nodeRear right range sensor raw data
/joint_statessensor_msgs/JointStatepublisher/serial_nodeWheels rotation angle
/batterysensor_msgs/BatteryStatepublisher/serial_nodeBattery voltage
/buttonsstd_msgs/UInt8publisher/serial_nodeUser buttons state, details in User buttons section
/posegeometry_msgs/PoseStampedpublisher/serial_nodePosition based on encoders
/odom/wheelnav_msgs/Odometrypublisher/msgs_conversionOdometry based on wheel encoders
/velocitygeometry_msgs/Twistpublisher/serial_nodeOdometry based on encoders
/imusensor_msgs/Imupublisher/msgs_conversionIMU data wrapped in standard ROS message type
/odomnav_msgs/Odometrypublisher/rosbot_ekfOdometry based on sensor fusion
/tftf2_msgs/TFMessagepublisher/rosbot_ekfROSbot position based on sensor fusion
/set_posegeometry_msgs/ PoseWithCovarianceStampedsubscriber/rosbot_ekfAllow to set custom state of EKF
/cmd_velgeometry_msgs/Twistsubscriber/serial_nodeVelocity commands
/configrosbot_ekf/Configurationservice server/serial_nodeAllow to control behaviour of CORE2 board, detaild in CORE2 config section

User buttons

User button message is published only once when button is pushed. In case when both buttons are presse at the same time, two messages will be pubilshed. Possible values are:

  • 1 - button 1 pressed
  • 2 - button 2 pressed

CORE2 config

Config message definition rosbot_ekf/Configuration:

string command
string data
---
uint8 SUCCESS=0
uint8 FAILURE=1
uint8 COMMAND_NOT_FOUND=2
string data
uint8 result

Available commands:

SLED - Set LED state, data structure is LED_NUMBER LED_STATE, where:

LED_NUMBER is number of LED, could be 1, 2 or 3

LED_STATE is desired LED state, could be 0 to set LED off and 1 to set LED on

For example, to set LED 2 on run:

$ rosservice call /config "command: 'SLED'
>data: '2 1'"

CSER - Configure servo, available parameters:

S - servo output [1:6], required with P and W parameters

V - voltage mdoe:

  • 0 - about 5V
  • 1 - about 6V
  • 2 - about 7.4V
  • 3 - about 8.6V

E - enable servo output [1,0]

P - set period in μs

W - set duty cycle in μs

CPID - Configure PID, available parameters:

kp - proportional gain (default: 0.8)

ki - integral gain (default: 0.2)

kd - derivative gain (default: 0.015)

out_max - upper limir of the PID output, represents pwm duty cycle (default: 0.80, max: 0.80)

out_min - lower limit of the PID output, represents pwm duty cycle when motor spins in opposite direction (default: -0.80, min: -0.80)

a_max - acceleration limit (default: 1.5e-4 m/s2)

speed_max - max motor speed (default: 1.0 m/s, max: 1.25 m/s)

GPID - Get PID configuration

To get PID configuration call with empty data field.

EIMU - Enable/disable IMU, possible values:

'1' - enable

'0' - disable

RIMU - Reset IMU (for Kalman related odometry)

To reset IMU MPU9250 call with empty data field.

EJSM - Enable/disable joint state message publication, possible values

'1' - enable

'0' - disable

RODOM - Reset odometry

To reset odometry call with empty data field.

CALI - Odometry valibration (update coefficients), data structure is: X Y, where

X - diameter_modificator value

Y - tyre_deflation value

EMOT - Enable/disable motors, possible values:

'0' - disconnect motors

'1' - connect motors

SANI - Set WS2812B LEDs animation This functionality is not default for ROSbots. It requires WS2812B LED stripe connected to servo 1 output on ROSbot back panel and rebuilding firmware with custom configuration.

To enable the WS2812B interface open the mbed_app.json file and change the line:

"enable-ws2812b-signalization": 0

to

"enable-ws2812b-signalization": 1

Possible values:

O - OFF

S <hex color code> - SOLID COLOR

F <hex color code> - FADE IN FADE OUT ANIMATION

B <hex color code> - BLINK FRONT/REAR ANIMATION

R - RAINBOW ANIMATION

SKIN - set ROSbot kinematics DIFFERENTIAL/MECANUM

By default robot always start with differential drive kinematics available to change by command:

$ rosservice call /config "command 'SKIN'
>data 'DIFF'

To set mecanum kinematics run:

$ rosservice call /config "command 'SKIN'
>data 'MEC'

MEC - mecanum kinematics DIFF - differential drive kinematics

External documentation

System reinstallation

In some cases you will need to restore ROSbot system to its default settings:

  • in case of accidential damage of the system,
  • to update the OS (it can be udpated remotely, but flashing the microSD card can be easier sometimes),
  • to clear all user changes and restore factory settings.

This process will differ depending on ROSbot version that you have. Find the full instruction here

Connect ROSbot to your Wi-Fi network

At first ROSbot need to be connected to your Wi-Fi network.

Option 1: Using display, mouse and keyboard

ROSbot is basically a computer running Ubuntu, so let's open it like a standard PC computer.

  1. Plug in a display with HDMI, mouse and keyboard into the USB port in the rear panel of ROSbot.
  2. Turn on the robot and wait until it boots.
  3. Open Application Launcher (Husarion Logo in top-left corner) > System Tools > Terminator app.

ROSbot 2R LxQT desktop environment

warning

ROSbot's graphical desktop environment requires about 3 minutes to start during first boot. The following ones require only about 1 minute after power on.

Connecting to Wi-Fi with netplan

Find available Wi-Fi networks with this Linux command:

husarion@rosbot2r:~$ ...
sudo iwlist wlan0 scan 

ROSbot 2R is using netplan instead of GUI Wi-Fi manager. It allows you to have all physical network interfaces configured from a single text file.

To connect your ROSbot to a Wi-Fi network edit /etc/netplan/01-network-manager-all.yaml file, eg. with nano:

husarion@rosbot2r:~$ ...
sudo nano /etc/netplan/01-network-manager-all.yaml

And modify lines 22-23 by replacing "PLACE_YOUR_WIFI_SSID_HERE" with your SSID (Wi-Fi network name) and "PLACE_YOUR_WIFI_PASSWORD_HERE" with your Wi-Fi password:

/etc/netplan/01-network-manager-all.yaml
network:
version: 2
renderer: networkd

ethernets:

all-eths:
match:
name: eth*
dhcp4: no
dhcp6: no
addresses:
- 192.168.77.2/24

wifis:

wlan0: # external USB Wi-Fi card (with antenna)
dhcp4: true
dhcp6: true
optional: true
access-points:
"PLACE_YOUR_WIFI_SSID_HERE":
password: "PLACE_YOUR_WIFI_PASSWORD_HERE"

save the file then, apply the new network setup:

husarion@rosbot2r:~$ ...
sudo netplan apply

You can check to which Wi-Fi network your ROSbot is connected by using this command:

husarion@rosbot2r:~$ ...
sudo iwgetid

If your Wi-Fi network setup is more complex (eg. if you want to connect to Eduroam based Wi-Fi that is popular in many universities), visit netplan configuration examples.

Open Linux terminal and type

husarion@rosbot2r:~$ ...
sudo ifconfig

to find your IP address (for wlan1 network interface). Save it for later.

Option 2: Using an Ethernet adapter

In the ROSbot 2R set there is one USB-Ethernet card.

  1. Turn on the robot and wait until it boots.

  2. Plug in the Ethernet adapter (included in a set) to a USB port in the rear panel.

  3. Plug in one end of the Ethernet cable into your computer and another one to the adapter.

  4. Set a static IP address on your computer for its Ethernet card in a 192.168.77.0/24 subnet, eg:

    • IPv4: 192.168.77.27
    • mask: 255.255.255.0
  5. To connect with ROSbot via ssh, type in your terminal application:

    user@mylaptop:~$ ...
    ssh husarion@192.168.77.2

    The default password for user husarion is also husarion.

At this point the Wi-Fi configuration process is the same as in the section above

Access ROSbot terminal using wireless connection

Connecting over LAN network

While ROSbot is connected to a Wi-Fi network, you can access it by using its IPv4 address by SSH:

user@mylaptop:~$ ...
ssh husarion@ROSBOT_IP

Connecting over the internet (optional)

You can access the robot not only in LAN but also over the Internet. The connection is based on Husarnet VPN.

Learn how to do it here.

Low level firmware installation

In the heart of each ROSbot there is a CORE2 board equipped with STM32F4 family microcontroller. The board is responsible for real time tasks like controlling motors, calculating PID regulator output or talking to distance sensors. High level computation is handled by SBC (single board computer) - ASUS Tinker Board (in ROSbot 2), UP Board (in ROSbot 2 PRO) or Raspberry Pi 4 (in ROSbot 2R).

In order to use ROSbot you have to flash ROSbot's CORE2 board with low level firmware.

The firmware running on STM32F4 microcontroller is open source and available on GitHub.

SSH to ROSbot over LAN network or VPN to get access to it's Linux terminal.

warning

Before flashing the firmware all previously launched docker containers must be stopped (you can display running containers with the docker ps command). Just execute the commands below:

husarion@rosbot2r:~$ ...
docker kill $(docker ps -q)
husarion@rosbot2r:~$ ...
docker container prune -f

The firmware for STM32 is available in the ROSbot's docker images.

All of husarion/rosbot:noetic, husarion/rosbot:melodic and husarion/rosbot:humble docker images include corresponding firmware for STM32F4 (a low level microcontroller that controls motors, GPIO ports and TOF distance sensors).

To flash the right firmware, open ROSbot's terminal and execute one of the following command:

  • for humble tag:
    husarion@rosbot:~$ ...
    docker run \
    --rm -it --privileged \
    husarion/rosbot:humble \
    /flash-firmware.py /root/firmware.bin

or if you use ROS noetic tag (can be replaced with melodic):

  • for differential drive (regular wheels):

    husarion@rosbot:~$ ...
    docker run --rm -it --privileged \
    husarion/rosbot:noetic \
    /flash-firmware.py /root/firmware_diff.bin
  • for omnidirectional wheeled ROSbot (mecanum wheels):

    husarion@rosbot:~$ ...
    docker run --rm -it --privileged \
    husarion/rosbot:noetic \
    /flash-firmware.py /root/firmware_mecanum.bin

ROS tutorials

ROS (Robot Operating System) provides libraries and tools to help software developers create robot applications. It provides hardware abstraction, device drivers, libraries, visualizers, message-passing, package management, and more. It's very powerful and functional tool dedicated to design robots. We created the set of ROS tutorials dedicated for this platform to make it easier to familiarize yourself with these frameworks.

All helpful documents and links in one place: