Maxime Raison

• Eng. Ir. PhD
• Full professor at Polytechnique Montréal

Table tennis with collaborative robots has been a challenge in robotics for decades, due to its unique challenges, primarily requiring precise real-time ball trajectory predictions to enable responsive, accurate gameplay. Traditional physical models, while widely studied, struggle with factors like spin, limiting accuracy. With advancements in comp...

Featured Application Following straightforward guidelines, feedforward neural networks enable to design an accurate model-free control structure for the fast trajectory tracking of robotic arms. Abstract This paper designs a minimal neural network (NN)-based model-free control structure for the fast, accurate trajectory tracking of robotic arms, c...

Tracking fast and accurate trajectories of robotic arms can be important in applications involving large movements, velocities, and accelerations. This would require either an accurate dynamic model of the arm or an aggressive tracking with high-gain feedback. Concretely, it can be difficult to obtain the accurate model, due to nonlinearities and u...

La modélisation 3D est le processus de développement d’objets virtuels. Ceux-ci sont importants dans la construction de scènes destinées à procurer l’expérience optimale chez l’utilisateur, comme par exemple en situation d’apprentissage par mises en situations et pratiques de tâches en virtuel. Il existe des logiciels spécifiques pour les divers do...

Les évidences appuyant l’utilisation d’environnement virtuel dans le domaine de la réadaptation s’accumulent depuis plusieurs années. Outre le potentiel à motiver l’utilisateur dans sa réadaptation, l’activité en milieu virtuel peut aider les thérapeutes à cibler la rééducation de mouvements et tâches précises. Ainsi, un environnement virtuel avec...

Objectives: To quantify the magnitude of spinal deformity in adolescent idiopathic scoliosis (AIS), the Cobb angle is measured on X-ray images of the spine. Continuous exposure to X-ray radiation to follow-up the progression of scoliosis may lead to negative side effects on patients. Furthermore, manual measurement of the Cobb angle could lead to u...

In the field of transcutaneous functional electrical stimulation (FES), open-loop and closed-loop control strategies have been developed to restore functions of the lower limbs: walking, standing up, maintaining posture, and cycling. These strategies require sensors that provide feedback information on muscle activity or biomechanics of movement. S...

To assess the severity and progression of adolescents with idiopathic scoliosis (AIS), radiography with X-rays is usually used. The methods based on statistical observations have been developed from 3D reconstruction of the trunk or topography. Machine learning has shown great potential to classify the severity of scoliosis on imaging data, general...

Background: Scoliosis curves present transverse plane deviations due to vertebral rotation. The Schroth method supports thoracic derotation by training patients to exert "derotational" breathing based on assumed enhanced ventilation in areas called "humps" in scoliosis and a patient's ability to voluntarily direct ventilation in less ventilated ar...

The potential of wearable robotics technology is undeniable. However, quantifying its value is difficult. Various types of exoskeleton robots have already been developed and tested for upper limb rehabilitation but, evaluations are not standardized, particularly in pediatric rehabilitation. This paper proposes a methodology for the quantitative eva...

Upper limb prostheses can greatly improve the condition of amputees. However, prosthetic mechanisms have different topologies and there is no consensus on the choice of an appropriate mechanism. This paper evaluates the impact of prosthetic mechanism topology on the prosthesis’ performance during daily tasks. The proposed multibody model is compare...

Sensorless and sensor-based upper limb exoskeletons that enhance or support daily motor function are limited for children. This review presents the different needs in pediatrics and the latest trends when developing an upper limb exoskeleton and discusses future prospects to improve accessibility. First, the principal diagnoses in pediatrics and th...

Table tennis has long fascinated roboticists as a particularly difficult task which requires fast movements, accurate control and adaptation to task parameters. In addition, the development of such devices is useful for educating the undergraduate students. Up to now, several groups have developed robotic manipulators playing table tennis and other...

Current saliency methods require to learn large-scale regional features using small convolutional kernels, which is not possible with a simple feed-forward network. Some methods solve this problem by using segmentation into superpixels, while others downscale the image through the network and rescale it back to its original size. The objective of t...

The need for upper limb assistive and wearable exoskeletons is growing in various fields, e.g. either to support patients with neuromuscular disabilities or to reduce the effort strains on workers. These exoskeletons should reduce the efforts required by the user during functional tasks (dynamic consideration) and should fit the user’s size (geomet...

The original article was published with an error. The corresponding author’s email address was missing during the online publication. The email address is presented here. The Original article has been corrected.

We read with great excitement the recent study of Colosio et al. [2] applying the bioenergetics approach [13] to the oxygen uptake response during constant-load exercise: first, because the observed maintenance of the overall cost of locomo-tion beyond the third minute of exercise in the heavy domain dissociates the slow component etiology from the...

(1) Background: Motion planning is an important part of exoskeleton control that improves the wearer’s safety and comfort. However, its usage introduces the problem of trajectory planning. The objective of trajectory planning is to generate the reference input for the motion-control system. This review explores the methods of trajectory planning fo...

Study design: Single-center prospective randomized controlled trial. Objective: To assess the computer-aided design/manufacturing (CAD/CAM) brace design approach, with and without added finite element modeling (FEM) simulations, after two years in terms of clinical outcomes, 3D correction, compliance and quality of life (QoL). Summary of backgr...

Over the last decades, the use of multibody dynamics in biomechanics research has grown considerably and holds significant promises for the health and biomedical industries. Nowadays, it allows estimating internal data of the body that would be impractical or impossible to obtain experimentally, e.g. individual muscle forces. Also, multibody dynami...

Gesture recognition is a key aspect of myoelectric control of upper-limb prostheses and is rather complex to achieve for transhumeral amputees. The prosthesis control of upper arm movements must rely only on the arm muscles, which were not involved in these gestures before the amputation. For decades, machine learning has been used in research for...

The human oxygen uptake responses to exercise step on-transients present different shapes depending on the overshoot and/or the “slow component” manifestations. The conventional First-Order Multi-Exponential (FOME) model incorporates delayed add-on terms to comprise these phenomena, increasing parameter quantity, requiring a delayed recruitment of...

The intervertebral efforts, i.e., forces and torques, during gait have been recognized as influencing the progression of scoliosis, due to the mechanical modulations according to the Hueter-Volkmann Law. Therefore, these efforts are key variables for posture correction and to control the progression of scoliosis. Using the intervertebral efforts du...

Current research in convolutional neural networks (CNN) focuses mainly on changing the architecture of the networks, optimizing the hyper-parameters and improving the gradient descent. However, most work use only 3 standard families of operations inside the CNN, the convolution, the activation function, and the pooling. In this work, we propose a n...

In recent years, there has been a rapid progress in solving the binary problems in computer vision, such as edge detection which finds the boundaries of an image and salient object detection which finds the important object in an image. This progress happened thanks to the rise of deep-learning and convolutional neural networks (CNN) which allow to...

Aim: To develop an index for quantitative assessment of the upper limb motor function in children with cerebral palsy before and after robot-assisted therapy. Method: An upper limb motor function index was developed using kinematic, surface electromyography and three-axis inertial measurements unit data collected from 15 children with cerebral pals...

The myoelectric prostheses are appealing solutions for transhumeral amputees as they can restore lost autonomy using the natural control of an arm. However, research still need to be performed to achieve intuitive control of prostheses by amputees, as very limited progress has been made in the past decades. Pattern recognition coupled with surface...

Most of powered ankle exoskeletons add considerable distal mass to the user which limit their capacity in reducing the metabolic energy of walking. The objective of the work presented in this paper is to develop an ankle exoskeleton with a minimum added distal mass compared to existing autonomous powered ankle exoskeletons while it can provide at l...

Assistive robotic arms have become popular to help users with upper limb disabilities achieve autonomy in their daily tasks, such as drinking and grasping objects in general. Usually, these robotic arms are controlled with an adapted joystick. Joysticks are user-friendly when it comes to a general approach to an object. However, they are not as int...

Low back pain is one of the most common musculoskeletal disorder. To reduce its incidences, some back exoskeletons have been designed and already commercialized. However, there is a gap between the phases of device and testing on subjects. In fact, the main unsolved problem is the lack of realistic simulation of human-device interaction. Consequent...

Several rehabilitation approaches have shown that robot-assisted therapy (robot-AT) can improve the quality of upper limb movements in children with cerebral palsy (CP). However, there is still no method for assessing upper limb motor function impairment using a combination of surface electromyography (sEMG) and inertial measurement unit (IMU) sens...

Current saliency methods require to learn large scale regional features using small convolutional kernels, which is not possible with a simple feed-forward network. Some methods solve this problem by using segmentation into superpixels while others downscale the image through the network and rescale it back to its original size. The objective of th...

Background: The pronator teres and pronator quadratus muscles are frequently injected with neuromuscular blocking agents to improve supination in children with spastic cerebral palsy and limited active elbow supination. However, determining by simple clinical examination whether these muscles are overactive during active movement is difficult. Ob...

Introduction: Gait analysis has often been recognized as helpful for the therapeutic follow-up of adolescents with idiopathic scoliosis (IS). Methods: A multibody model of the human body was developed to display the intervertebral efforts along the spine of each adolescent with IS, and highlight the efforts that significantly differ from typical...

In computer vision, the gradient and Laplacian of an image are used in many different applications, such as edge detection, feature extraction and seamless image cloning. To obtain the gradient of an image, it requires the use of numerical derivatives, which are available in most computer vision toolboxes. However, the reverse problem is more diffi...

Introduction When designing and installing implants, stress analyses should be performed in conditions close to those of everyday use. Specifically, for femoral implants, cyclic loading during gait has been demonstrated to produce fatigue failure. However, there is still no consensus in the literature regarding which modelling procedure is the most...

Background: The aim of this study was two-fold: (1) to quantify the variability of upper limb electromyographic patterns during elbow movements in typically developing children and children with unilateral spastic cerebral palsy, and to compare different amplitude normalization methods; (2) to develop a method using this variability to detect (a)...

A reliable evaluation of muscle forces in the human body is highly desirable for several applications in both clinical and research contexts. Several models of muscle force distribution based on non-invasive measurements have been proposed since 1836 (Weber and Weber, 1836), amongst which Crowninshield's model (Crowninshield and Brand, 1981), which...

Introduction/Background Many children with neuromuscular disorders have limited motion of their upper limb. To sustain their little upper limb movement possibilities against gravity and offer them more autonomy, the objective of this study was to develop an exoskeleton that would be light, easy-to-make and costless. The application took the form o...

Computer vision is a growing field with a lot of new applications in automation and robotics, since it allows the analysis of images and shapes for the generation of numerical or analytical information. One of the most used method of information extraction is image filtering through convolution kernels, with each kernel specialized for specific app...

In Computer Vision, edge detection is one of the favored approaches for feature and object detection in images since it provides information about their objects boundaries. Other region-based approaches use probabilistic analysis such as clustering and Markov random fields, but those methods cannot be used to analyze edges and their interaction. In...

Objectives: The aim of this study is to identify the association between levels of severity of nurodevelopmental disorders and disabilities (NDD/D) in children, their household socio-economic status (SES), and the frequency of visits to a healthcare provider; and (2) to examine how the severity of disability differs with these determinants among ND...

Recent studies have shown the ability of transhumeral amputees to generate surface electromyography (sEMG) patterns associated to distinct phantom limb movements of the hand, wrist and elbow. This ability could improve the control of myoelectric prostheses with multiple degrees of freedom (DoF). However, the main issue of these studies is that thes...

None of the physical testing, nor the goniometers currently used to assess upper limb function have a high validity, sensitivity or reliability. The reachable workspace, i.e. the area covered by the farthest points a subject can reach by hand without moving his/her body, shows promise but has yet to be validated, particularly in terms of reproducib...

Objective: This study aims to present an automatic method using parametric curve fitting modeling to increase the accuracy of decomposition of 3D-GRF during double stances under each foot. Methods: The decomposition method was applied to the global 3D-GRF using 3rd order polynomial, sine, and sine-sigmoid functions. The computed 3D-GRF was compa...

Robotic assistance for people affected by motor deficits is a fast growing field. In this context, two major challenges remain in terms of automated scene analysis and automated object prehension. More specifically, the most robust of current segmentation methods are still computationally intensive, preventing the automation of objects prehension f...

The congenital or traumatic amputation of upper limbs leads to strong mobility and socio-psychological disabilities. The amputees can choose between three types of prostheses: cosmetic, body-powered and myoelectric. The myoelectric prostheses are controlled via electromyographic activity, they provide control over more degrees of freedom. The devel...

Treatment for cerebral palsy depends upon the severity of the child’s condition and requires knowledge about upper limb disability. The aim of this study was to develop a systematic quantitative classification method of the upper limb disability levels for children with spastic unilateral cerebral palsy based on upper limb movements and muscle acti...

Treatment for cerebral palsy depends upon the severity of the child’s condition and requires knowledge about upper limb disability. The aim of this study was to develop a systematic quantitative classification method of the upper limb disability levels for children with spastic unilateral cerebral palsy based on upper limb movements and muscle acti...

Wearable sensors are useful in the field of robotics, rehabilitation, biomechanics and medicine. In this work, we present a wearable measurement system equipped with a flexible, stretchable and tactile sensors array. The system contains four strain gauges connected to four separate Wheatstone bridges. The strain gauges were embedded into silicone D...

Le REAplan dispositif médical robotisé pour la rééducation des membres supérieurs

Myoelectric prosthesis is an electronic device designed to mimic human anatomy and to replace a missing body part for an amputee. Today some prostheses can provide the users with several degrees of freedom. But the major challenges in their design remain related to the control of such devices using a variety of sensors. Regarding this aspect, strai...

Over the last decade, eye tracking systems have been developed and used in many fields, mostly to identify targets on a screen, i.e. a plane. For novel applications such as the control of robotic devices by the user vision, there is a great interest in developing methods base on eye tracking to identify target points in free three dimensional envir...

Over the last decade, eye tracking systems have been developed and used in many fields, mostly to identify targets on a screen, i.e. a plane. For novel applications such as the control of robotic devices by the user vision, there is a great interest in developing methods base on eye tracking to identify target points in free three dimensional envir...

Introduction Les patients avec une tétraplégie C5/C6 ont leur triceps paralysé tandis que leurs deltoïdes et fléchisseurs du coude sont préservés. La chirurgie de réanimation de l’extension du coude a pour objectif de reconstruire le mouvement paralysé, en transférant le tendon du biceps (technique Zancolli) ou du deltoïde postérieur (technique Mob...

Introduction La thérapie motrice induite par la contrainte (TMIC) améliore la motricité du membre supérieur atteint (MSA) des enfants hémiparétiques, en les forçant à n’utiliser que celui-ci plusieurs heures par jour pendant plusieurs semaines. L’objectif de cette étude est de discuter la validité d’un protocole à quantifier l’effet de la TMIC sur...

Background: Although recurrent anterior shoulder instability (RASI) is a common condition in young patients, no studies to date have measured the 3-dimensional (3D) locked position of the glenohumeral joint during an anterior dislocation. Therefore, our goal was to estimate it with 3D computed tomography (CT) scans. Methods: Patients in this pro...

Objective: To address the roles and mechanisms of co-activation in two flexor/extensor pairs during elbow extension in children with cerebral palsy (CP). Methods: 13 Typically Developing (TD) and 13 children with unilateral spastic CP performed elbow extension/flexion at different speeds. Elbow angle and velocity were recorded using a 3D motion...

The aim of this study is to determine the intra- and inter-session reliability of non-normalized surface electromyography (sEMG) on the muscles actuating the forearm during maximum voluntary isometric contractions (MVIC). A sub-objective of this study is to determine the intra- and inter-session reliability of forearm MVIC force or torque, which is...

Myoelectric prostheses aim to help amputees to experience partial function of the absent organ. The sensors usually used to control the prostheses are surface electromyography (sEMG) electrodes, of which the number tends to increase with the increase of the number of degrees of freedom in the recent prostheses, i.e. dozens of sensors today. However...

One approach to increasing the confidence of muscle force estimation via musculoskeletal models is to minimize the root mean square error (RMSE) between joint torques estimated from electromyographic-driven musculoskeletal models and those computed using inverse dynamics. We propose a method that reduces RMSE by selecting subsets of combinations of...

Objective Children with spastic unilateral cerebral palsy (SUCP) have an involved upper limb (IUL) restricted in active range of motion and in velocity when performing elbow extension, due to a combination of muscle impairments. One of them is excessive muscle co-activation (CA). CA usually has a functional role, particularly in joint stabilization...

Background: Joint torques are generally of primary importance for clinicians to analyze the effect of a surgery and to obtain an indicator of functional capability to perform a motion. Given the current need to standardize the functional evaluation of the upper limb, the aim of this paper is to assess (1) the variability of the calculated maximal...

The use of exoskeletons as an aid for people with musculoskeletal disorder is the subject to an increasing interest in the research community. These devices are expected to meet the specific needs of users, such as children with cerebral palsy (CP) who are considered a significant population in pediatric rehabilitation. Although these exoskeletons...

Background: The objective of this study was to provide preliminary measures of the distance between the supraspinatus, infraspinatus, and subscapularis footprints and the acromion, coracoacromial ligament, and coracoid process, during dynamic arm elevations through the entire range-of-motion. Methods: Two healthy men performed maximum adduction,...

Background: Crouch gait results in an increase of the joint stress due to an excessive knee flexion. Daily walking exercises, even when performed at a self-selected speed, may result in a decrease of the extensor muscle strength which could lead to a more severe crouch gait pattern. The aim of this study was to assess the impact of a short walking...

This study presents a failure analysis of a femoral orthopaedic implant. This implant is a locking compression plate that was fixed to a broken femur using two types of screws: locking and compression screws. The study elucidates the causes of an in situ premature failure of the plate and screws. Chemical analysis, hardness tests, and microstructur...

This paper presents the results obtained from a research work investigating the performance of different Adaptive Neuro-Fuzzy Inference System (ANFIS) models developed to predict excitation forces on a dynamically loaded flexible structure. For this purpose, a flexible structure is equipped with acceleration transducers at each degree of freedom an...

Background: Children with spastic hemiplegic cerebral palsy are restricted in their daily activities due to limited active ranges of motion of their involved upper limb, specifically at the elbow. Their impaired muscles are frequently targeted by anti-spastic treatments that reduce muscle tone. But these treatments do not necessarily improve the li...

Designing exoskeletons presents challenges related to multibody modeling, especially to improve the human-robot integration by optimizing the topology, the kinematics, and the inertia effects, and to get real-time feedback on the effort levels applied to the human body by the exoskeleton. In this context, the objective of this overview is to draw a...

For the last decade, exoskeletons have emerged as a viable support in the daily lives of people with musculoskeletal disorders. Today, research in this area is growing fast to allow these exoskeletons to best meet the specific needs of different user categories, such as the children with cerebral palsy (CP), the largest population in pediatric reha...

The manual control of manipulator robots can be complex and time consuming even for simple tasks, due to a number of degrees of freedom (DoF) of the robot that is higher than the number of simultaneous commands of the joystick. Among the emerging solutions, the eyetracking, which identifies the user gaze direction, is expected to automatically comm...

Introduction: The quantification of internal joint efforts could be essential in the development of rehabilitation tools for patients with musculo-skeletal pathologies, such as scoliosis. In this context, the aim of this study was to compare the hips joint mediolateral forces during gait, between healthy subjects and adolescents with left lumbar or...