I have been looking to build something like the Husarion 4wd. It is simply awesome, but I have a few questions:
As per my understanding, to control the motors, I need a Microsontroller (something like the Arduino or the ESP32). I do not see that with the Husarion bot. How does this work then?
The Microcontroller then sends signals to a computer via ros serial (usually a Raspberry Pi) which runs the ROS nodes. Where is the Pi here?
So basically the CORE-2 hardware - Could you please provide more details about what it is?
There is a microcontroller in ROSbot, it is a STM32 device, it is placed on a CORE2 board.
ROSbots are sold with Asus TInkerBoard or Aaeon UpBoard, depending on version. Both devices are single board computers like RPi and in the same form factor, but differ in performance.
Rosserial is connecting SBC and microcontroller in both directions.
The SBC sends velocity command to micrcontroller via rosserial.
The microcontroller sends odometry and sensor data to SBC via rosserial.
User is interacting with SBC only.
Please also look on the block diagram of ROSbot 2.0:
The ROS-related things are not shown on this hardware diagram but you can see “UART” interface between SBC and CORE2-ROS. This is a physical interface for Rosserial.