Hi Jae,
You can control 2 Arduino blocks to Simulink by using the Master-Slave Architecture to ensure both boards can communicate effectively and work together to control your robot's motors and read encoder signals.
You can have a setup where the two Arduino's are connected using an I2C communication protocol. This way, the Master Arduino can initiate communication and request data from the Slave Arduino where as the slave respond to requests from the Master Arduino with the Encoder data.
The Master can then be used to control the motors. Connect three encoder signals to the available interrupt pins. For the Slave Arduino, use this to read the fourth encoder signal and any additional sensors or inputs.
The Simulink setup would involve using Arduino Support Package in Simulink to configure each board. You may create a single model with two distinct sections for each board.
Also, make sure that each Arduino has a unique I2C address to avoid conflicts and that the data transfer between the two Arduinos is synchronized, especially if the data is time-sensitive.
For more information you can refer to the documentation for the Arduino Support Package : https://www.mathworks.com/hardware-support/arduino.html
Hope this helps
