ArticleSensors (Basel, Switzerland)2026
A Hierarchical FSM-BT Control Architecture for a Passive/Active Rehabilitation Exoskeleton.
Article in Sensors (Basel, Switzerland), 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
0 citing papers in PubMed.
No citing paper in PubMed yet.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
3 authors.
Funding
Abstract
Rehabilitation exoskeletons require supervisory control that can preserve globally safe operating modes while executing local therapeutic behaviors reactively. Pure Finite-State Machine (FSM) implementations provide explicit mode supervision but become increasingly coupled as behaviors and recovery transitions are added, whereas Behavior Trees (BTs) provide modular reactive execution but do not inherently encode a unique global operating mode. This work presents an application-specific hierarchical FSM-BT architecture for the SARA passive-active lower-limb rehabilitation platform. The novelty is not the generic combination of FSMs and BTs; rather, it lies in the rehabilitation-oriented separation of global therapeutic-mode supervision and event-priority safety arbitration from parameterizable BT execution and local recovery before escalation. The architecture was evaluated exclusively in a custom Python Software-in-the-Loop (SIL) environment using an eight-degree-of-freedom second-order joint model, a 100 Hz plant integration rate, a 10 Hz supervisory FSM, and 50 Hz BT execution. Thirty Monte Carlo trials were performed for each of four scenarios and for three functionally equivalent architectures (FSM-only, BT-only, and FSM-BT), for 360 comparative trials with a fixed random seed. The proposed FSM-BT architecture achieved a 98.3% overall trial-success rate, compared with 89.2% for FSM-only and 92.5% for BT-only. Its mean software-level unsafe-condition-to- Emergency Stop response was 71.9 ms, significantly lower than the 159.7 ms FSM-only response (p<10-8, paired Wilcoxon test), while BT-only produced the same safety timing because it used the same 50 Hz local evaluation cadence. The active-assistance model yielded a mean eight-DOF angular RMSE of 2.42°. A structural extension study further required 54 edit operations to add six therapeutic routines to FSM-BT, versus 60 for BT-only, 96 for a hierarchical state-machine baseline, and 138 for FSM-only.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.