Wearable Ankle Research Articles

Wearable ankle assistance robot for a human walking with different loads

Abstract. To reduce energy consumption while a human is walking with different loads, an active energy storage mechanism and a gait cycle prediction method are proposed, and then a wearable ankle assistance robot is developed. A motor, a clutch, and elastic rods are placed strategically in the active energy storage mechanism to achieve energy storage and release. During the period when the ankle does not generate torque, the clutch is closed, and the elastic rods are driven by the motor to produce deformation for energy storage. When the ankle generates torque, the motor is stopped and the clutch is opened, and then energy is released. Assisted force is transmitted to the human heel by a flexible transmission device to achieve walking assistance. The deformation length of the elastic rods can be changed to achieve assisted force adjustment for different loads. Based on the hip angular displacement and heel pressure, the gait cycle can be obtained with the proposed prediction method, and then assistance control can be achieved. Consequently, the development of a wearable ankle assistance robot is realized, a walking assistance experiment with different loads is completed, and the net metabolic cost is used to indicate the energy consumption. The experimental results show that the net metabolic cost of the participants is reduced by averages of 5.30 %, 5.67 %, and 4.84 % with 0, 4, and 8 kg loads respectively. The reduced net metabolic costs are compared with other research results; the reduced net metabolic costs are close to the others, but the motor power in this work is lower.

Personalized Wearable Ankle Robot Using Modular Additive Manufacturing Design

Personalized Wearable Ankle Robot Using Modular Additive Manufacturing Design

Classification of Sprain and Non-sprain Motion using Deep Learning Neural Networks for Ankle Sprain Prevention

A smart wearable ankle sprain prevention device would require an intelligent monitoring system that can classify data from the sensors as sprain or non-sprain motion. This paper aims to explore Deep Neural Network method, specifically the Long Short Term Memory Fully Convolutional Network (LSTM-FCN) for classifying sprain and non-sprain motion. A study is conducted on 11 participants to record sprain and non-sprain motions, which are used to train and test the LSTM-FCN model and previously used Support Vector Machine (SVM) model. It has been demonstrated that the LSTM-FCN model is more accurate at classifying sprain and non-sprain motion. The LSTM-FCN also proved to be more useful as its architecture allows for the Class Activation Mapping (CAM) method to be employed. The CAM method allows for the identification of temporal regions of the time series that contribute most or least to the classification decision of the LSTMFCN. Visualizing the regions of high or low contribution makes it easy to see patterns in the data correlation with sprain motion and better understand why certain non-sprain data can be misclassified as sprain motion. Overall, LSTM-FCN is found to be a viable method for the classification of sprain and non-sprain motion.

Developing of a wearable ankle rehabilitation robotic device

People with walking disorders caused by accidents or stroke can undergo treatment to restore their mobility. Traditional therapy is time-consuming and time-consuming. Therefore, a new trend was born – to facilitate rehabilitation and reduce the patient’s time. Rehabilitation robotics is an area that is constantly evolving, and new mechanisms have recently been developed to help people regain their mobility. This paper presents a 3-RPS parallel manipulator for the restoration of the ankle joint with three degrees of freedom. Parallel manipulator 3-RPS with three degrees of freedom, which was introduced by K. Hunt in 1983 as one of the sedentary parallel manipulators. Since then, 3-RPS has attracted a lot of attention from robotics and biomedical engineering engineers.

Human-in-the-loop layered architecture for control of a wearable ankle–foot robot

Intelligent wearable robotics is a promising approach for the development of devices that can interact with people and assist them in daily activities. This work presents a novel human-in-the-loop layered architecture to control a wearable robot while interacting with the human body. The proposed control architecture is composed of high-, mid- and low-level computational and control layers, together with wearable sensors, for the control of a wearable ankle–foot robot. The high-level layer uses Bayesian formulation and a competing accumulator model to estimate the human posture during the gait cycle. The mid-level layer implements a Finite State Machine (FSM) to prepare the control parameters for the wearable robot based on the decisions from the high-level layer. The low-level layer is responsible for the precise control of the wearable robot over time using a cascade proportional–integral–derivative (PID) control approach. The human-in-the-loop layered architecture is systematically validated with the control of a 3D printed wearable ankle–foot robot to assist the human foot while walking. The assistance is applied lifting up the human foot when the toe-off event is detected in the walking cycle, and the assistance is removed allowing the human foot to move down and contact the ground when the heel-contact event is detected. Overall, the experiments in offline and real-time modes, undertaken for the validation process, show the potential of the human-in-the-loop layered architecture to develop intelligent wearable robots capable of making decisions and responding fast and accurately based on the interaction with the human body.

Feasibility evaluation of a dual-mode ankle exoskeleton to assist and restore community ambulation in older adults.

Age-related deficits in plantar flexor muscle function during the push-off phase of walking likely contribute to the decline in mobility that affects many older adults. Isolated strengthening of the plantar flexor muscles has failed to improve push-off power or walking economy in this population. New mobility aids and/or functional training interventions may help slow or prevent ambulatory decline in the elderly. The overarching objective of this study was to explore the feasibility of using an untethered, dual-mode ankle exoskeleton for treating walking disability in the elderly; testing the device in assistance mode as a mobility aid to reduce energy consumption, and as a resistive gait training tool to facilitate functional recruitment of the plantar flexor muscles. We recruited 6 older adults between the ages of 68 to 83 years to evaluate the feasibility of the dual-mode exoskeleton across two visits. On the first visit, we quantified acute metabolic and neuromuscular adaption to ankle exoskeleton assistance during walking in older adults, and subsequently determined if higher baseline energy cost was related to an individual's potential to benefit from untethered assistance. On the second visit, we validated the potential for push-off phase ankle resistance combined with plantar pressure biofeedback to facilitate functional utilization of the ankle plantar flexors during walking. We also conducted a twelve-session ankle resistance training protocol with one pilot participant to explore the effects of gait training with wearable ankle resistance on mobility and plantar flexor strength. Participants reached the lowest net metabolic power, soleus variance ratio, and soleus iEMG at 6.6 ± 1.6, 19.8 ± 1.6, and 5.8 ± 4.9 minutes, respectively, during the 30-minute exoskeleton assistance adaptation trial. Four of five participants exhibited a reduction (up to 19%) in metabolic power during walking with assistance relative to baseline, but there was no group-level change. Participants who had greater baseline metabolic power exhibited a greater reduction during walking with assistance. Walking with resistance increased stance-phase soleus iEMG by 18 - 186% and stance-phase average positive ankle power by 9 - 88% compared to baseline. Following ankle resistance gait training, the participant exhibited a 5% increase in self-selected walking speed, a 15% increase in fast walking speed, a 36% increase in 6-min-walk-test distance, and a 31% increase in plantar flexor strength compared to pre-intervention measurements. Our results suggest that dual-mode ankle exoskeletons appear highly applicable to treating plantar flexor dysfunction in the elderly, with assistance holding potential as a mobility aid and resistance holding potential as a functional gait training tool. We used an untethered design to maximize the relevance of this for informing the design of intervention studies that may take place at home and in the community to improve mobility and quality of life in older adults. Future studies with larger sample sizes are recommended to expand on the results of this feasibility investigation.

Variable Damping Control for pHRI: Considering Stability, Agility, and Human Effort in Controlling Human Interactive Robots

This article presents a multi-degree-of-freedom variable damping controller to manage the trade-off between stability and agility and to reduce user effort in physical human-robot interaction. The controller accounts for the human body's inherent impedance properties and applies a range of robotic damping from negative (energy injection) to positive (energy dissipation) values based on the user's intent of motion. To evaluate the effectiveness of the proposed controller in balancing the trade-off between stability/agility and reducing user effort, two studies are performed on both the human upper-extremity and lower-extremity to represent both industrial and rehabilitation applications of the proposed controller. These studies required subjects to perform a series of multidimensional target reaching tasks while the human user interacted with either the end-effector of a robotic arm for the upper-extremity study or a wearable ankle robot for the lower-extremity study. Stability, agility, and user effort are quantified by a variety of performance metrics. Stability is quantified by both overshoot and stabilization time. Mean and maximum speed are used to quantify agility. To quantify the user effort, both overall and maximum muscle activation, and mean and maximum root-mean-squared interaction force are calculated. The results of both the upper- and lower-extremity studies demonstrate that the controller is able to reduce user effort while increasing agility at a negligible cost to stability.

Entrainment During Human Locomotion Using a Soft Wearable Ankle Robot

An entrainment study was conducted with a novel soft robotic ankle-foot orthosis (SR-AFO) consisting of a pair of flat fabric pneumatic artificial muscles (ff-PAM). Entrainment capabilities of a lighter soft robotic orthosis were compared with heavy rigid robotic counterparts reported previously. To measure the SR-AFO's capacity to manifest gait entrainment, periodic pneumatic plantarflexion perturbations equal to the calculated increase from the subject's preferred gait frequency were applied to the ankle. Two days of experiments were conducted. In the Day 1 experiment, perturbations were applied from the baseline to a 15% increase in the gait frequency with steps of 3% at a fixed treadmill speed of the subject's preferred walking speed. In the Day 2 experiment, in order to investigate the maximum entrainment capability with the SR-AFO, perturbations were applied from the baseline with steps of 5% with proportionally increasing walking speed until subjects failed to maintain phase locking for 50 or more consecutive steps. In the Day 1 experiment, all 10 subjects were entrained at the highest 15% condition. In the Day 2 experiments, the average basin of entrainment was 39.3 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\pm$</tex-math></inline-formula> 9.2%. Importantly, phase locking was always observed in the push-off phase of the gait cycle in both days of experiments. The observed basin of entrainment with the SR-AFO was substantially higher than the previously reported value (+7%) with a heavy rigid ankle robot, confirming the potential of the SR-AFO to significantly extend the effectiveness of the entrainment paradigm in gait adaptation and rehabilitation.

Variable Impedance Control for pHRI: Impact on Stability, Agility, and Human Effort in Controlling a Wearable Ankle Robot

This letter introduces a variable impedance controller which dynamically modulates both its damping and stiffness to improve the trade-off between stability and agility in coupled human-robot systems and reduce the human user's effort. The controller applies a range of robotic damping from negative to positive values to either inject or dissipate energy based on the user's intent of motion. The controller also estimates the user's intent of direction and applies a variable stiffness torque to stabilize the user towards an estimated ideal trajectory. To evaluate the controller's ability to improve the stability/agility trade-off and reduce human effort, a study was designed for human subjects to perform a 2D target reaching task while coupled with a wearable ankle robot. A constant impedance condition was selected as a control with which to compare the variable impedance condition. The position, speed, and muscle activation responses were used to quantify the user's stability, agility, and effort, respectively. Stability was quantified spatially and temporally, with both overshoot and stabilization time showing no statistically significant difference between the two experimental conditions. Agility was quantified using mean and maximum speed, with both increasing from the constant impedance to variable impedance condition by 29.8% and 59.9%, respectively. Effort was quantified by the overall and maximum muscle activation data, both of which showed a ~10% reduction in effort. Overall, the study demonstrated the effectiveness of the variable impedance controller.

Effects of wearable ankle robotics for stair and over-ground training on sub-acute stroke: a randomized controlled trial

BackgroundWearable ankle robotics could potentially facilitate intensive repetitive task-specific gait training on stair environment for stroke rehabilitation. A lightweight (0.5 kg) and portable exoskeleton ankle robot was designed to facilitate over-ground and stair training either providing active assistance to move paretic ankle augmenting residual motor function (power-assisted ankle robot, PAAR), or passively support dropped foot by lock/release ankle joint for foot clearance in swing phase (swing-controlled ankle robot, SCAR). In this two-center randomized controlled trial, we hypothesized that conventional training integrated with robot-assisted gait training using either PAAR or SCAR in stair environment are more effective to enhance gait recovery and promote independency in early stroke, than conventional training alone.MethodsSub-acute stroke survivors (within 2 months after stroke onset) received conventional training integrated with 20-session robot-assisted training (at least twice weekly, 30-min per session) on over-ground and stair environments, wearing PAAR (n = 14) or SCAR (n = 16), as compared to control group receiving conventional training only (CT, n = 17). Clinical assessments were performed before and after the 20-session intervention, including functional ambulatory category as primary outcome measure, along with Berg balance scale and timed 10-m walk test.ResultsAfter the 20-session interventions, all three groups showed statistically significant and clinically meaningful within-group functional improvement in all outcome measures (p < 0.005). Between-group comparison showed SCAR had greater improvement in functional ambulatory category (mean difference + 0.6, medium effect size 0.610) with more than 56% independent walkers after training, as compared to only 29% for CT. Analysis of covariance results showed PAAR had greater improvement in walking speed than SCAR (mean difference + 0.15 m/s, large effect size 0.752), which was in line with the higher cadence and speed when wearing the robot during the 20-session robot-assisted training over-ground and on stairs.ConclusionsRobot-assisted stair training would lead to greater functional improvement in gait independency and walking speed than conventional training in usual care. The active powered ankle assistance might facilitate users to walk more and faster with their paretic leg during stair and over-ground walking.Trial registration: ClinicalTrials.gov NCT03184259. Registered on 12 June 2017.

Feasibility of Augmenting Ankle Exoskeleton Walking Performance With Step Length Biofeedback in Individuals With Cerebral Palsy.

Most people with cerebral palsy (CP) suffer from impaired walking ability and pathological gait patterns. Seeking to improve the effectiveness of gait training in this patient population, this study developed and assessed the feasibility of a real-time biofeedback mechanism to augment untethered ankle exoskeleton-assisted walking performance in individuals with CP. We selected step length as a clinically-relevant gait performance target and utilized a visual interface with live performance scores. An adaptive ankle exoskeleton control algorithm provided assistance proportional to the real-time ankle moment. We assessed lower-extremity gait mechanics and muscle activity in seven ambulatory individuals with CP as they walked with adaptive ankle assistance alone and with ankle assistance plus step-length biofeedback. We achieved our technical validation goal by demonstrating a strong correlation between estimated step length and real step length (R = 0.771, p < 0.001). We achieved our clinical feasibility goal by demonstrating that biofeedback-plus-assistance resulted in a 14% increase in step length relative to baseline (p ≤ 0.05), while no difference in step length was observed for assistance alone. Additionally, we observed near immediate improvements in lower-extremity posture, moments, and positive power relative to baseline for biofeedback-plus-assistance (p < 0.05), with none, or more-limited improvements observed for assistance alone. Our findings suggest that providing real-time biofeedback and using step length as the target can be effective for increasing the rate at which individuals with CP improve their gait mechanics when walking with wearable ankle assistance.

Intensive In-Bed Sensorimotor Rehabilitation of Early Subacute Stroke Survivors With Severe Hemiplegia Using a Wearable Robot.

Rehabilitation for stroke survivors with severe motor impairment remains challenging. Early motor rehabilitation is critical for improving mobility function post stroke, but it is often delayed due to limited resources in clinical practice. The objectives of this study were to investigate the feasibility and effectiveness of early in-bed sensorimotor rehabilitation on acute stroke survivors with severe hemiplegia using a wearable ankle robot. Eighteen patients (9 in the study group and 9 in the control group) with severe hemiplegia and no active ankle movement were enrolled in acute/subacute phase post stroke. During a typical 3-week hospital stay, patients in the study group received ankle robot-guided in-bed training (50 minutes/session, 5 sessions/week), including motor relearning under real-time visual feedback of re-emerging motor output, strong passive stretching under intelligent control, and game-based active movement training with robotic assistance. Whereas the control group received passive ankle movement in the mid-range of motion and attempted active ankle movement without robotic assistance. After multi-session training, the study group achieved significantly greater improvements in Fugl-Meyer Lower Extremity motor score (p = 0.007), plantarflexor strength (p = 0.009), and active range of motion (p = 0.011) than controls. The study group showed earlier motor recovery for plantarflexion and dorsiflexion than the control group (p < 0.05). This study showed that in-bed sensorimotor rehabilitation guided by awearable ankle robot through combining motor relearning in real-time feedback, strong passive stretching, and active movement training facilitated early motor recovery for stroke survivors with severe hemiplegia in the acute/subacute phase.

Effects of Lightweight Wearable Ankle Exoskeleton in an Individual With Parkinson Disease

Background: This is a feasibility study aimed to investigate the effects of a novel lightweight ankle exoskeleton on gait and balance in an individual with Parkinson disease (PD). Case Description: An 85-year old woman with a 5-year history of PD (Hoehn and Yahr stage 2.5) participated in the study. The participant received 4 visits over 4 weeks including 1 evaluation and three 30-minute training sessions wearing the ankle exoskeleton. Results: The participant demonstrated a 26% reduction in metabolic cost during walking and nearly 10% improvement in peak anterior-posterior center-of-pressure displacement during balance testing with untethered exoskeleton assistance compared with baseline. Conclusion: Participant-specific ankle exoskeleton is a feasible and safe intervention that can improve walking economy as well as balance in individuals with PD.

0438 Automatic Nighttime Agitation and Sleep Disruption Detection Using a Wearable Ankle Device and Machine Learning

Abstract Introduction Nighttime agitation behavior such as wandering and restlessness during awake and sleep in people with Alzheimer’s disease (AD) is expensive to manage and adversely affects sleep. Nighttime agitation is mostly noted by subjective caregiver reports. An automated process for this assessment would improve clinical management. Here we report on the RestEaZeTM system that uses an ankle band and machine learning to automatically classify sleep status and nighttime agitation behaviors in older adults with AD. Methods We collected data on 7 adults (mean: 81 years, SD: 10.6) with AD. They wore the RestEaZeTM ankle band with a 3-axis accelerometer, a 3-axis gyroscope, and three textile capacitive sensors. A trained Research Assistant (RA) continuously observed for wandering, restlessness, wake, and sleep between 5pm and 7am using the Cohen Mansfield Agitation Inventory (CMAI). We merged, and band-pass filtered the data and divided it into 10-second non-overlapping windows. CMAI labels and time-series features (scaled using StandardScaler) extracted from the RestEaZeTM data were used to train a Random Forest binary classifier. The significant features were extracted based on the impact on the p-value for the classifier. We used the Synthetic Minority Oversampling Technique (SMOTE) to balance the dataset and performed 5-fold cross-validation with a 67-33 train-test split. Results We report the sensitivity, specificity, accuracy, and Area-under-the Curve (AUC) for the ROC curve for the classifiers: (1) Sleep/Awake: sensitivity=0.95, specificity=0.87, accuracy=0.92, AUC=0.97; (2) Wandering/Non-Wandering: sensitivity=0.85, specificity=0.99, accuracy=0.98, AUC=0.99; and (3) Restless/Non-Restless: sensitivity=0.84, specificity=0.84, accuracy=0.84, AUC=0.92. The significant features were related to the intensity of movements. Conclusion Our preliminary results show the feasibility of using RestEaZeTM for quantitatively measuring nighttime agitation. These can provide clinically useful objective measures of agitation that can be automatically transmitted to clinical or research records with minimal staff time requirements. Support The authors acknowledge the funding support from the National Institute on Aging under award R01AG051588 and Arbor Pharmaceuticals for support for Horizant and the matching placebo.

DESIGN OF AN ULTRA-WIDEBAND UHF RFID READER ANTENNA FOR WEARABLE ANKLE TRACKING APPLICATIONS

In this paper, a broadband reader antenna is designed and manufactured for wearable ankle strap applications. The frequency range covered for S 11 < −10 dB is from 850 MHz to 1650 MHz with dipole like radiation pattern in free space. The proposed broadband antenna is manufactured with a semi-flex (Taconic RF-35) and flexible (Kapton) substrates. A good agreement between simulations and measurements has been achieved. Prototypes performances have been tested by measuring the reading distance. The maximum reading distance obtained is about 1.46 m at 865 MHz with an output power of the transmitter (P T X) of 25 dBm. Results of functional RFID test show that the proposed antenna can be used as an RFID reader antenna when it is placed on the ankle of the human body.

Wearable Ankle Rehabilitation Device Based on Novel Series Elastic Actuator

To assist patients with ankle diseases in completing rehabilitation training, a wearable ankle orthosis was presented in this paper. Firstly, the SEA-DTS (the series elastic actuator based on the double-tendon-sheath transmission mechanism and torsion spring), the execution mechanism of the ankle joint and the control system were described. Then, a series of experiments regarding trajectory tracking, moment step response, and position frequency response are carried out to study the mechanical characteristics of the wearable ankle orthosis. Results show that the participation of the SEA-DTS helps the orthosis work smoothly, while causes a maximum deviation of 3.56° in the trajectory tracking, a 10ms-delay and a maximum 16% overshoot in the moment step response performance, the bandwidth of the orthosis is 5.5Hz. Finally, the results obtained from two isokinetic dynamometer experiments prove the effectiveness of the wearable ankle orthosis, which means the proposed orthosis can assist patients with ankle diseases in completing rehabilitation training.

A Battery-Powered Ankle Exoskeleton Improves Gait Mechanics in a Feasibility Study of Individuals with Cerebral Palsy

Neuromuscular impairment associated with cerebral palsy (CP) often leads to life-long walking deficits. Our goal was to evaluate the ability of a novel untethered wearable ankle exoskeleton to reduce the severity of gait pathology from CP. In this clinical feasibility study of five individuals with CP, we used instrumented gait analysis to quantify how powered plantar-flexor assistance affected gait mechanics following multi-visit acclimation. Compared to how each participant walked normally, walking with untethered exoskeleton assistance resulted in improved ankle plantar-flexion and knee extension; residual flexion deformity across the lower-extremity improved by a clinically significant 14.4° (p = 0.022). Powered plantar-flexor assistance increased average total positive ankle power by 44% (p = 0.037), and resulted in a 30% reduction in average negative biological ankle power (p = 0.004) and a 29% reduction in average positive hip power (p = 0.009). These findings suggest that powered ankle assistance augmented, rather than simply replaced, biological function to produce a more efficient gait pattern, which was corroborated by a 19% improvement in metabolic cost of transport (p = 0.011). This study provides evidence in support of the continued investigation of ankle assistance in mobility and rehabilitation interventions for this patient population.

Mechanical design and preliminary tests of VS-AnkleExo

Exoskeletons and wearable robotic systems have advanced substantially over the last decade for gait assistance, rehabilitation and load-carrying purposes. Currently, there are commercially available devices with stiff actuators. However, these actuators cannot adapt to their unpredictable environments. Thus, compliant actuators like series elastic and variable stiffness actuators have been implemented in exoskeletons and active orthoses. This paper presents a novel design and experimental characterization of a compliant actuator with adjustable stiffness for a lower limb wearable ankle robot (VS-AnkleExo). The proposed actuator is designed to mimic the behavior of biological ankle and maximizes the compliance between user and robot during a gait cycle. The adjustable stiffness of actuator is achieved through a controllable transmission ratio mechanism. Both transparency and tracking performance experiments are performed to demonstrate reduced the user–robot interaction force and improved the tracking performance of the proposed actuator, respectively. Experimental results showed that interaction forces between the user and robot are minimized in the transparency experiments, while the actuators proposed are able to track the given torque signals at various frequencies in the tracking experiments.

Flexible thin antenna solution for wearable ankle bracelet applications with GNSS and BLE connectivity

AbstractA thin antenna structure to operate in GNSS (Global Navigation Satellite System) and BLE (Bluetooth Low Energy) communication standards is proposed. The antenna was built on a flexible and thin Kapton material inserted between 2 layers of bovine leather, suitable for limited weight and slim ankle bracelet designs. Proposed antenna structure consist of 2 opposed planar inverted F antennas modified using matching stubs, sharing the same substrate and ground plane, with total size of 96.8 × 35 × 4.14 mm. The ground plane area of the antenna can be used for electronic circuit and battery placement. The antenna structure operates in the following specific 4 bands: BeiDou (1561 MHz), GPS (1575 MHz), GLONASS (1602 MHz), and BLE (2400 MHz). The antenna exhibited great agreement between electromagnetic simulations in ADS Momentum and measurements performed into 3D anechoic chamber with anthropomorphic leg‐foot model from Speag. The antenna peak gain is approximately −1.8 dBi for GNSS bands and −2.0 dBi for BLE.

Development Of A Wearable Ankle Rehabilitation Device For Patient With Calf Muscles Flexibility Problems

This paper presents the development process and analysis of a wearable ankle rehabilitation device designed for patient with calf muscles flexibility problems. The device is used to help patient in exercising the ankle to strengthen, lengthen and maintain the calf muscles. By using a joystick module to control the actuation of the servo motor, the ankle brace moves the ankle to plantar flexion and dorsiflexion movements. Besides that, MyoWareTM Muscle Sensor is used to generate electromyography (EMG) signal from the calf muscles to monitor the servo motor. Exercising the ankle frequently can increase the calf muscles flexibility. The robotic ankle brace device accommodates the robot-guided at-home therapy requirements and is user-friendly. This allowed patient to perform exercise on the ankle more frequent and the recovery process can be reduced effectively. Other than being used as a treatment, this ankle brace is suitable for daily exercise too. Keywords: rehabilitation; electromyography; servo-motor; control systems