Question about return value of the rL_fun(t) function in the waypoint_shaped_flat_trajectory.m

[mateus-amarante]

Transfering @lienguang0624's #1 (comment) to here

Thank you very much for your prompt reply. I have roughly understood the structure of your paper. Next, I want to repeat your simulation work, but I encountered some difficulties while reading your source code.
The return value of the rL_fun(t) function in the waypoint_shaped_flat_trajectory.m file is a matrix of 280121. I know that 2801 represents the time node, but how is this 21 obtained, and what does it specifically mean? (I can only analyze that rL_fun probably represents the position information of the suspanded load, but these are only three variables(xl,yl,zl))
The same problem is also true for yaw_fun(t). Why is the function running the result of 28013 if only one state variable is yaw?
Do you have any suggestions for reading your simulation program?
I am very sorry for taking up your precious time and looking forward to your reply.

[mateus-amarante]

The return value of the rL_fun(t) function in the waypoint_shaped_flat_trajectory.m file is a matrix of 280121. I know that 2801 represents the time node, but how is this 21 obtained, and what does it specifically mean? (I can only analyze that rL_fun probably represents the position information of the suspanded load, but these are only three variables(xl,yl,zl))

The differentially flat trajectory demands the load position be defined up to its 6th derivative. The columns are:

xL, yL, zL, xL_dot, yL_dot, zL_dot, ..., xL_6dot, yL_6dot, zL_6dot

They are used in the differentially_flat_trajectory.m function

[mateus-amarante]

Do you have any suggestions for reading your simulation program?

I'll think more about it. I noticed the README.md file is outdated. I'll take this opportunity to fix it.