Locomotion Variability and User Experience in Smart Wheelchair Human-Robot Interaction

2026-08-11

AI Summary

This study addresses a critical limitation in conventional shared-control strategies for intelligent wheelchairs, which often suppress the natural variability inherent in user movement, thereby undermining users’ sense of autonomy and degrading interaction quality. The authors propose a novel variability-preserving shared-control approach that, for the first time in human–robot collaboration, treats movement variability as a functional feature rather than mere noise. Their method actively preserves task-irrelevant degrees of freedom while ensuring task-critical performance. In user experiments comparing unassisted control, traditional shared control, and the proposed strategy, results demonstrate that—without compromising task performance—the new approach significantly enhances users’ perceived autonomy and system usefulness, outperforming existing methods.

Abstract

Human movement is inherently variable, with variability structured according to task relevance: movements are typically more consistent at task-critical points and more flexible elsewhere. In human-robot interaction (HRI), however, model-based assistance strategies commonly assume deterministic human behavior and suppress such variability, potentially altering how interactions are experienced and lowering sense of agency. While movement variability is increasingly recognized as functionally meaningful, its deliberate preservation in assisted interaction, and its consequences for user experience, remain underexplored. In this paper, we empirically investigate how different assistance strategies shape human movement variability, task performance, and subjective interaction experience in a shared control setting. We introduce an autonomy-supportive shared control strategy that preserves users' natural movement structure. This approach is evaluated in a user study in which participants push an intelligent powered wheelchair under three conditions: no assistance, conventional variability-reducing assistance, and variability-preserving assistance. While task-relevant performance remained comparable across assisted modes, preserving natural movement variability led to more favorable interaction experiences. In particular, participants reported significantly higher perceived agency compared to conventional assistance and highest perceived usefulness. These findings suggest that variability-aware assistance can support both performance and user autonomy in physical human-robot collaboration. More broadly, the results highlight the importance of designing assistive robotic systems that respect the embodied structure of human movement rather than treating variability as noise to be neglected or eliminated.

Problem

• locomotion variability
• human-robot interaction
• shared control
• user experience
• sense of agency

Innovation

• movement variability
• shared control
• human-robot interaction
• sense of agency
• autonomy-supportive assistance