Advancing Home Rehabilitation - The PlanAID Robot’s Approach to Upper-Body Exercise Through Impedance Control

Sep 30, 2026

Uploaded by jayni

Rehabilitation robots help address the growing demand for therapy, yet many existing systems remain bulky and costly, limiting frequent, intensive repetition. This paper develops an impedance-based control strategy for safe, compliant upper-body passive and active exercises using the low-cost PlanAID robot built with consumer-grade components. A high-precision force sensor evaluates performance. Results show comparable reaction force targeting (28 N) and reflected inertia (1.1 kg) versus legacy systems, with reduced stability margins limiting virtual spring constant to 1100 N/m, though stiffness remains adequate for real use.

LanguageEnglish

CategoryHealthcare

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Pages24

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Abstract

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1. Introduction

Article Advancing Home Rehabilitation: The PlanAID Robot’s Approach to Upper-Body Exercise Through Impedance Control David Breton 1,2, *, Thierry Laliberté 2, Andréanne K. Blanchette 1,3 and Alexandre Campeau-Lecours 1,2 Academic Editors: Xiaojun Chen and Jiangchang Xu Received: 2 December 2025 Revised: 23 December 2025 Accepted: 25 December 2025 Published: 26 December 2025 Copyright: © 2025 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license. 1 Centre Interdisciplinaire de Recherche en Réadaptation et Intégration Sociale (Cirris), Quebec City, QC G1M 2S8, Canada; alexandre.campeau-lecours@gmc.ulaval.ca (A.C.-L.) 2 Robotics Laboratory, Department of Mechanical Engineering, Université Laval, Quebec City, QC G1V 0A6, Canada 3 School of Rehabilitation Sciences, Faculty of Medicine, Université Laval, Quebec City, QC G1V 0A6, Canada * Correspondence: [dabre38@ulaval.ca](dabre38@ulaval.ca) Abstract Rehabilitation robots are a leading solution towards bridging the gap between the growing number of rehabilitation patients requiring therapy and the limited availability of healthcare professionals. However, existing robotic systems are often bulky and expensive, limiting their ability to provide widespread, repetitive, and intensive exercises. This paper presents the development of an impedance-based control strategy designed to provide safe and compliant upper-body passive and active exercises on the low-cost PlanAID robot, which is built using consumer-grade components. The system’s functionalities are evaluated using a high-precision force sensor. Results show that the PlanAID exhibits performance comparable to seminal devices such as the MIT-Manus, achieving a similar applicable reaction force target of 28 N and reflected inertia of 1.1 kg. Although the overall performance is comparable, the low-cost PlanAID prototype suffers from reduced coupled stability margins, limiting the maximum achievable virtual spring constant to 1100 N/m. Despite this limitation, the stiffness values required in practical applications remain low, suggesting that the PlanAID could potentially be a viable candidate for real-world rehabilitation. Initial user feedback was obtained through a preliminary qualitative trial involving healthy subjects. Keywords: rehabilitation engineering; rehabilitation robotics; motor learning; impedance control; control engineering; force sensing 1. Introduction The prevalence of neurological conditions is rising, primarily due to population aging and increased life expectancy after a lesion. Although the number of healthcare professionals is increasing, there is still a gap between the supply of services and the needs of the population to be met [1] . This imbalance makes conventional therapy methods increasingly labour-intensive and time-limited per patient, which can negatively impact recovery. However, early, repetitive, and intensive rehabilitation exercises are often critical in achieving optimal recovery outcomes [2,3] . The use of rehabilitation robots may represent a viable strategy to address this issue by enhancing the rehabilitation process. Indeed, such technologies enable individuals with upper-limb sensorimotor impairments to perform a higher number of exercise repetitions and to carry out a greater range of daily activities with increased autonomy. Rehabilitation robots have been in development since the early 1990s, with the MIT Manus—now known commercially as InMotion—being one of the earliest examples. This end-effector robot, with two planar degrees of freedom (DoF), set the foundation for future advancements in robotic rehabilitation [4] . Over the years, various designs have been explored, including serial 3-DoF robots and exoskeleton robots [5] . Despite these innovations, the planar end-effector design remains widely used in contempora

FAQs

Why does the paper focus on robotic rehabilitation for upper-body exercises?

It targets the gap between increasing patient needs and limited availability of healthcare professionals, which makes conventional therapy labor-intensive and time-limited.

What control strategy is presented for the PlanAID robot?

The paper presents an impedance-based control strategy intended to provide safe and compliant upper-body passive and active exercises.

How does the PlanAID’s performance compare with well-known earlier systems?

Performance is reported as comparable, achieving a similar applicable reaction force target of 28 N and reflected inertia of 1.1 kg.

Sep 30, 2026

Uploaded by jayni