Compensation Effect Amplification Control (CEAC): A movement-based approach for coordinated position and velocity control of the elbow of upper-limb prostheses

2026-01-08

arXiv.org

AI Summary

This study addresses the challenge of achieving intuitive, continuous, and speed-adjustable coordinated control of intermediate joints—such as the elbow—in upper-limb prostheses. To this end, the authors propose a novel control paradigm that leverages trunk flexion-extension movements as input signals. By modeling the natural coupling between trunk motion and prosthetic joint dynamics and incorporating a controllable time-delay mechanism, the approach restores inter-joint coordination while avoiding excessive compensatory postures. The integrated system combines trunk motion sensing, coupling-based modeling, delay-regulated control algorithms, and an active, over-actuated prosthetic platform. In drawing and multi-target reaching tasks, users achieved trajectory control performance approaching that of a natural arm, maintained ergonomic trunk postures, and effectively balanced movement demands between the trunk and elbow.

Technology Category

• Intelligent Robots: Manipulation
• Humans and AI: Intelligent User Interfaces
• Cognitive Modeling & Cognitive Systems: Adaptive Behavior

Application Category

• User Modeling, Personalization and Recommendation: User modeling and simulation for interactive and conversational systems
• Responsible Web: Machine-in-the-loop, human agency and autonomy
• Semantics and Knowledge: Data modeling to support human-machine intelligence, including LLMs agents, intelligent system behavior, explanations, and user-friendly interactions

Abstract

Despite advances in upper-limb (UL) prosthetic design, achieving intuitive control of intermediate joints - such as the wrist and elbow - remains challenging, particularly for continuous and velocity-modulated movements. We introduce a novel movement-based control paradigm entitled Compensation Effect Amplification Control (CEAC) that leverages users'trunk flexion and extension as input for controlling prosthetic elbow velocity. Considering that the trunk can be both a functional and compensatory joint when performing upper-limb actions, CEAC amplifies the natural coupling between trunk and prosthesis while introducing a controlled delay that allows users to modulate both the position and velocity of the prosthetic joint. We evaluated CEAC in a generic drawing task performed by twelve able-bodied participants using a supernumerary prosthesis with an active elbow. Additionally a multiple-target-reaching task was performed by a subset of ten participants. Results demonstrate task performances comparable to those obtained with natural arm movements, even when gesture velocity or drawing size were varied, while maintaining ergonomic trunk postures. Analysis revealed that CEAC effectively restores joint coordinated action, distributes movement effort between trunk and elbow, enabling intuitive trajectory control without requiring extreme compensatory movements. Overall, CEAC offers a promising control strategy for intermediate joints of UL prostheses, particularly in tasks requiring continuous and precise coordination.

Problem

• upper-limb prosthesis
• elbow control
• intuitive control
• velocity modulation
• coordinated movement

Innovation

• Compensation Effect Amplification Control
• trunk-prosthesis coordination
• velocity-modulated control
• upper-limb prosthesis
• intuitive movement control