کنفرانس مهندسی برق ایران

صفحه اصلی / سی و چهارمین کنفرانس بین المللی مهندسی برق

A Data-Driven Two-Layer MPC with Safety Filter for Range-of-Motion-Constrained Tracking in a Knee Rehabilitation Exoskeleton

نویسندگان :

Ashkan Jelodar¹ Mohammad Olyai² Khalil Alipour³ Bahram Tarvirdizadeh⁴ Majid Sorouri⁵ Mohammad Ghamari⁶

1- دانشگاه تهران 2- دانشگاه تهران 3- دانشگاه تهران 4- دانشگاه تهران 5- Department of Electronic Engineering, Maynooth University, Maynooth, Co. Kildare, Ireland 6- Electrical Engineering Department, California Polytechnic State University

کلمات کلیدی :

Rehabilitation exoskeleton،knee joint،model predictive control،safety filter،control barrier function،data- driven identification،range of motion

چکیده :

Rehabilitation exoskeletons must track therapeutic joint trajectories while strictly respecting range-of-motion (ROM) limits to protect the user. This paper proposes a practical two-layer control architecture for a 1-DOF knee rehabilitation exoskeleton. First, an offline data-driven identification stage fits a subject-specific linear inverse-dynamics model from measured motion via constrained ridge regression. Second, an online performance-and-safety controller combines linear model predic- tive control (MPC) with a lightweight discrete-time safety filter. The MPC optimizes tracking subject to actuator magnitude and torque-rate limits, while the safety filter solves a scalar quadratic program at each step to enforce a buffered safe set inside the physical ROM under bounded unmodeled accelerations. In simulation with a 20 ms sampling time over a 10 s trial, the controller achieves low tracking error across nominal, high- disturbance, and reduced-torque conditions. In a near-boundary reference case that is intentionally infeasible with respect to the buffered limit, the safety filter intervenes finitely and minimally to maintain safety, whereas a baseline without the safety layer exhibits a small overshoot at the physical ROM bound. The results support the approach as a computationally efficient supervisory safety layer that can be integrated with standard MPC for ROM-constrained rehabilitation control.