JMIR Publications

ABSTRACT

Background:

Robotic mobility aids with sit-to-stand (STS) support may help older adults reduce physical effort during a demanding, fall-prone daily task.

Objective:

This paper reports a feasibility evaluation of the “SkyWalker” robotic walker, which provides powered STS assistance via actuated lower handles. The two trajectories (Linear and S-shape) were selected to examine how assistance profile shape influences feasibility, biomechanics, and user experience.

Methods:

Seven older adult patients with mobility challenges were enrolled from a rehabilitation hospital. One withdrew during the robot familiarization (unable to stand up) without attempting any study trial, and six completers (4 women, 2 men; aged 70–84 years) form the analyzed sample. Participants completed three within- subject conditions: SkyWalker with the Linear trajectory, SkyWalker with the S-shape trajectory, and a conventional rollator. We quantified STS task performance, perceived exertion (Borg CR10), kinematics (center-of-gravity, CoG, height), kinetics (vertical ground-reaction force, Fz, normalized to body weight), and technology acceptance using an adapted Tele-healthcare Satisfaction Questionnaire–Wearable Technology (TSQ-WT). Participant-level data are the primary presentation. Condition effects were tested with exact nonparametric tests.

Results:

Under Linear assistance, 27 of 30 repetitions (90%) were successful (mean 4.50, SD 0.84; 4 of 6 participants at 5/5) and perceived exertion was the lowest of the three conditions (Borg CR10 mean 1.50, SD 1.38; lower than the rollator in 3 of 6 participants, unchanged in 2, higher in 1). Under S-shape assistance, 21 of 30 repetitions (70%) were successful (mean 3.50, SD 1.97; 3 of 6 at 5/5), with exertion comparable to the conventional rollator (mean 2.50, SD 2.43 vs 2.33, SD 1.63). All 6 completers achieved 5 of 5 repetitions with the conventional rollator, so robotic assistance did not increase the number of successful transfers in this cohort. Exact tests showed no significant condition effect on exertion (Friedman chi-square 2.1, df=2, exact P=.40; Kendall W=0.18) or success (Friedman chi-square 5.0, df=2, exact P=.11; Kendall W=0.42). Group CoG curves showed earlier, more monotonic elevation for Linear, and per-participant Fz showed greater between-participant variability in load-transfer timing under S-shape. Technology acceptance was heterogeneous (TSQ-WT totals 22–77 of 80; 4 of 6 participants at 64 or higher).

Conclusions:

Powered STS assistance was feasible for most assisted transfers: 27 of 30 repetitions (90%) succeeded under the Linear trajectory, which also produced the lowest mean perceived effort of the three conditions. The S-shape trajectory was more demanding, producing more partial completions and no effort reduction relative to the conventional rollator. In this first evaluation of SkyWalker with its intended users, the assistance profile, not powered assistance itself, is the variable to prioritize in further testing, and the results, which motivate trajectory personalization and brief familiarization, are informing the design of the next SkyWalker generation.