how to model Turtlebot3_Segway ?

[swgu931]

Hello!

I appreciate your valuable works especially turtlebot3 and segway.
I wanted to find the turtlebot3 segway modeling before designing controller but I cannot find it inside of the source code below.
https://github.com/ROBOTIS-GIT/OpenCR/tree/master/arduino/opencr_arduino/opencr/libraries/turtlebot3/examples/turtlebot3_friends/turtlebot3_segway

I am doubtful that you control the turtlebot3_segway without any modeling but heuristic or "trial and error" approach.

Thanks in advance for your help.

[ROBOTIS-Will]

Hi @swgu931

Thank you for your interest in TurtleBot3 Friends!
You can find the modeling of the segway from TurtleBot3 eManual below.
https://emanual.robotis.com/docs/en/platform/turtlebot3/locomotion/#turtlebot3-friends-segway
Thank you!

[swgu931]

I mean the model that you control with PID controller, namely the state space equations or funtional equation for control engineers.
The following could be one of examples.
x_dot = Ax + Bu
y = Cx

Thanks.

[ROBOTIS-Will]

Hi @swgu931

The PID controller model of the example is tuned heuristically based on the IMU pitch reading of the TurtleBot3 Segway.
Thank you.

[swgu931]

I made the similar one that you tested on the youtube. you can see the picture.
I have two questions below.

1. what is the right one about x, y direction of IMU on the OpenCR board ?
   The picture on the below was my current alignment.
2. The value of P, I, D in the source code is your final tuned value, isn't it ?

Thanks in advance.