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ROSbot 3

Overviewโ€‹

ROSbot is a ROS powered 4x4 drive autonomous mobile robot platform equipped with LIDAR, RGB-D camera, IMU, encoders, distance sensors.

Available in three versions: 3 / 3 PRO (current version), 2R / 2 PRO (discontinued) and 2 (deprecated).

ROSbot 3 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
  • IMU: BNO055 (accelerometer + gyro)
  • rear panel providing interfaces for additional modules

ROSbot versionsโ€‹

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

  • Raspberry Pi 5 (ARM64 architecture) quad-core ARM-8 Cortex A76 @ 2.4GHz, 8GB RAM and 64 GB MicroSD flash memory.
  • 3D camera: Luxonis OAK-D Lite / Pro
  • LIDAR: RPLIDAR C1 / S2
1 / 1

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Gazebo Simulation Modelโ€‹

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 guideโ€‹

Specificationโ€‹

ROSbot 3 dimensionsROSbot 3 dimensions
AttributeDescription
Dimensions with camera and LiDAR200 x 233 x 197 mm / 7.9 x 9.2 x 7.7 in [L x W x H]
Dimensions without camera200 x 233 x 141 mm / 7.9 x 9.2 x 5.6 in [L x W x H]
Dimensions without camera and LiDAR200 x 233 x 103 mm / 7.9 x 9.2 x 4.0 in [L x W x H]
Weight2,84 kg / 100 oz (with camera and LiDAR), 2,45 kg / 86 oz (without camera and LiDAR)
Standard wheel diameter / Clearance / Wheelbase84 mm / 23 mm / 106 mm
Mecanum wheel diameter / Clearance / Wheelbase97 mm / 30 mm / 106 mm
Chassis materialPowder-coated aluminum plate, 1.5 mm thick
Maximum translational velocity1.0 m/s
Maximum rotational velocity420 deg/s (7.33 rad/s)
Maximum load capacityUp to 5 kg / 176 oz *not in continuous work
Battery life1.5h - 5h

Componentsโ€‹

Scheme 2RScheme 2R

Components descriptionโ€‹

ComponentQuantityDescription
Infrared distance sensor4VL53L0X Time-of-Flight distance sensor with up to 200 cm range, more details
Built-in Microcontroller1STM32F407.
DC motor4Xinhe Motor XH-25D, Motor used: RF-370, 6VDC nominal, 6200rpm. Maximum mechanical power: 4W, no load speed at the output shaft: 180 rpm, stall torque at the output shaft: 2.9 kg*cm, stall current: 2.0A, gear ratio: ~34 (exact ratio is 30613/900)
Encoder4Magnetic, 48cpr, 12 poles
Batteries3Li-Ion 18650 protected, rechargeable batteries, 3500mAh capacity, 3.7V nominal voltage. Note: Device may be shipped interchangeably with similar batteries.
ComponentQuantityDescription
SBC1Raspberry Pi 5 (ARM64 architecture) quad-core ARM-8 Cortex A76 @ 2.4GHz, 8GB RAM and 64 GB MicroSD flash memory. The SBC runs on Ubuntu-based OS, customized to use ROS.
3D camera1Luxonis OAK-D Lite (in ROSbot 3) / OAK-D Pro (in ROSbot 3 PRO)
LIDAR1RPLIDAR C2 (in ROSbot 3) / S2 (in ROSbot 3 PRO), 360 degree, more details
IMU sensor1Intelligent 9-axis absolute orientation sensor BNO055, more details
Antenna1Dual-band, connected to the Wi-Fi USB adapter.

Block diagramโ€‹

Graphic representation of ROSbot 3 components and connections between them.

Block diagramBlock diagram

Rear panel descriptionโ€‹

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 supplyโ€‹

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 โ€œ3Sโ€. 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 โ€œbal Bxxโ€ 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 โ€“ 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 ROSbotโ€‹

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 โ€œLiPo BATTโ€ mode and press [Start].
  3. Use arrows to select โ€œLiPo CHARGEโ€ 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 โ€œ11.1V(3S)โ€ 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 โ€œbeepโ€ 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

Softwareโ€‹

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 20.04 or 22.04, which runs on the SBC (Raspberry Pi 4, UP Board, or Asus Tinker Board) and contains all components needed to start working with ROS or ROS 2 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 2 / ROS packages and Docker containersโ€‹

All software on ROSbot XL are based on docker containers. List of available containers you can find here.

ROS 2 / ROS APIโ€‹

QUICK NOTE

This API is based on the ROS 2 firmware, which you can find more information about in the rosbot_ros2_firmware repository.

Use bringup.launch.py from rosbot_bringup to start all base functionalities for ROSbot 2, 2 PRO, 2R. It consists of following parts:

  • ekf_node from robot_localization, it is used to fuse wheel odometry and IMU data. Parameters are defined in ekf.yaml in rosbot_bringup/config. It subscribes to /rosbot_base_controller/odom and /imu_broadcaster/imu published by ros2 controllers and publishes fused odometry on /odometry/filtered topic

    Subscribes

    • /rosbot_base_controller/odom (nav_msgs/Odometry)
    • /imu_broadcaster/imu (sensor_msgs/Imu)

    Publishes

    • /tf (tf2_msgs/TFMessage) - base_link->odom transform
    • /odometry/filtered (nav_msgs/Odometry)

  • controller.launch.py from rosbot_controller, it loads robot model defined in rosbot_description as well as ros2 control rosbot_hardware_interfaces. It also starts controllers:

    • joint_state_broadcaster
    • rosbot_base_controller - DiffDriveController
    • imu_broadcaster

    Subscribes

    • /cmd_vel (geometry_msgs/Twist)
    • /_motors_responses (sensor_msgs/JointState)
    • /_imu/data_raw (sensor_msgs/Imu)

    Publishes

    • /tf (tf2_msgs/TFMessage)
    • /tf_static (tf2_msgs/TFMessage)
    • /_motors_cmd (std_msgs/Float32MultiArray)
    • /rosbot_base_controller/odom (nav_msgs/Odometry)
    • /imu_broadcaster/imu (sensor_msgs/Imu)

Use micro_ros_agent to communicate with all firmware functionalities.

ros2 run micro_ros_agent micro_ros_agent serial -D $SERIAL_PORT serial -b 576000

  • rosbot_ros2_firmware it is a micro-ROS node on CORE2 inside ROSbot 2R, 2 PRO, 2. It is used to publish all the sensor data such as wheels positions, IMU measurements, battery level and buttons states from firmware to ROS2 and also to subscribe command values such as motors speeds, servos periods, servos parameters and LEDs states. Subscribes

    • /cmd_ser (std_msgs/msg/UInt32MultiArray[6])
    • /led/left (std_msgs/msg/Bool)
    • /led/right (std_msgs/msg/Bool)
    • /_motors_cmd (std_msgs/msg/Float32MultiArray[4])

    Publishes

    • /_motors_response (*sensor_msgs/msg/JointState)
    • /_imu/data_raw (sensor_msgs/msg/Imu)
    • /battery (sensor_msgs/BatteryState)
    • /range/fr (sensor_msgs/msg/Range)
    • /range/fl (sensor_msgs/msg/Range)
    • /range/rr (sensor_msgs/msg/Range)
    • /range/rl (sensor_msgs/msg/Range)
    • /button/left (std_msgs/msg/Bool)
    • /button/right (std_msgs/msg/Bool)

    Parameters

    • servo_enable_power (Bool)
    • servo_voltage (Double):
      • 5.0V
      • 6.0V
      • 7.4V
      • 8.6V
    • servo[0...5]_enable (*Bool_) e.g. servo2_enable
    • servo[0...5]_period (*UInt32_) e.g. servo2_period

Command line examplesโ€‹

  • Motors driving (e.g. go forward)

    ros2 topic pub /_motors_cmd std_msgs/msg/Float32MultiArray "data: [1.0, 1.0, 1.0, 1.0]"

  • Servos steering

    # Choose power supply voltage for the servos e.g. 5.0V
    ros2 param set /rosbot_ros2_firmware servo_voltage 5.0

    # Enable power for the servos
    ros2 param set /rosbot_ros2_firmware servo_enable_power true

    # Set the control period in microseconds e.g. 20 000us for the servo5
    ros2 param set /rosbot_ros2_firmware servo5_period 20000

    # Enable PWM output for the servo e.g. for the servo5
    ros2 param set /rosbot_ros2_firmware servo5_enable true

    # Send duty cycle to the servos
    ros2 topic  pub /cmd_ser std_msgs/msg/UInt32MultiArray "data: [0, 0, 0, 0, 0, 2000]"

  • LED blinking

    # Turn on the left LED
    ros2 topic pub /led/left std_msgs/msg/Bool "data: true"

    # Turn off the left LED
    ros2 topic pub /led/left std_msgs/msg/Bool "data: false"

External documentationโ€‹

System reinstallationโ€‹

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

  • in case of accidental damage of the system,
  • to update the OS (it can be updated 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 networkโ€‹

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

Option 1: Using display, mouse and keyboardโ€‹

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 a terminal.

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 netplanโ€‹

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 adapterโ€‹

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 connectionโ€‹

Connecting over LAN networkโ€‹

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)โ€‹

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 installationโ€‹

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. There are:

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 snap.

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

sudo rosbot.flash

ROS / ROS 2 Tutorialsโ€‹

ROS (Robot Operating System) offers libraries and tools to help software developers create robotic 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.

Reference projectsโ€‹

warning

Please note that the following projects are based in Docker only (including running the ROS 2 driver for ROSbot 3). Before running those demos, please stop the ROS 2 driver running in snap first:

sudo rosbot.stop
linkdescription
rosbot-gamepadControl the robot manually using a Logitech F710 gamepad
rosbot-telepresenceStream a live video from Orbbec Astra to a window on your PC. Control the robot using teleop-twist-keyboard
rosbot-autonomyA combination of mapping and navigation projects allowing simultaneous mapping and navigation in unknown environments.

Here is an example map generated with the rosbot-autonomy project.

map example

All helpful documents and links in one place: