Servo (Integral) State-Dependent Riccati Equation (SDRE)

The code simulates the servo state-dependent Riccati equation (SDRE) and compares it with conventional and integral SDRE.

The code is related to Section 4 of the paper:

Morgado, A. G., S. R. Nekoo, G. Heredia, and A. Ollero, "Bidirectional-thruster multirotor for perimeter pipe inspections (BiMPPI): A nonlinear optimal integral-SDRE design," ISA Transactions (2025). DOI: https://doi.org/10.1016/j.isatra.2025.03.015

It simulates the regulation control of a single degree of freedom model with a servo state-dependent Riccati equation (SDRE) and compares it with an integral SDRE and conventional SDRE. The integrator can eliminate the steady-state error in the system, which is an advantage of this method. It can also be experimentally implemented on a robotic or mechatronics system. One example can be seen here:

https://www.youtube.com/watch?v=8mxeQC33Cw4