System Identification and acados-Based NMPC for Swing-Up Control of an Underactuated Double Pendulum

Sichen Li; Venkateswarlu Reddy Konkala; Xiaojie Ning; Abhishek Alaya Udupa

System Identification and acados-Based NMPC for Swing-Up Control of an Underactuated Double Pendulum

Systems and Control 2026-08-09 v1

Authors: Sichen Li , Venkateswarlu Reddy Konkala , Xiaojie Ning , Abhishek Alaya Udupa

Abstract

We identify a base-parameter model of CloudPendulum cell 203 and track an offline swing-up reference with acados SQP-RTI NMPC at a target rate of 400 Hz. A 5 mNm passive-joint assist enabled development-stage swing-up and recovery. In organizer-run testing (16 trials of 300 s per configuration on cells 201--204), assisted pendubot and acrobot mean uptime scores were 80.19 s and 74.61 s. Acrobot scored zero on two cells, and seven trials ended on safety-limit exceptions. Because the assist is prohibited in evaluation, these results are diagnostic rather than qualification scores.

Keywords

system identification nonlinear model predictive control underactuated double pendulum swing-up control acados

Cite

@article{arxiv.2608.08952,
  title  = {System Identification and acados-Based NMPC for Swing-Up Control of an Underactuated Double Pendulum},
  author = {Sichen Li and Venkateswarlu Reddy Konkala and Xiaojie Ning and Abhishek Alaya Udupa},
  journal= {arXiv preprint arXiv:2608.08952},
  year   = {2026}
}