Pressure Ucler Prevention System Based in Capacitive Sensors

Jorge Cazho-Tobar, Jorge Barbecho-Sarango, Freddy Bueno-Palomeque


Excessive pressure applied on bony prominence during a long period is the main extrinsic factor associated to pressure ulcers (PU). This is a common situation in patients using a wheelchair as a movement support for most of the day activities and patients with cerebral palsy. In this work, a system to measure and monitor the pressure levels generated between a person and a wheelchair is developed for pressure ulcer prevention. The system consists of 64 capacitive sensors on an xx cm2 area; the pressure levels are shown permanently on a smartphone and recorded to analyze on a computer through a graphical user interface (GUI) in Matlab. Each sensor support a load of 9.00 kg and the complete system has an energetic independence of 48 h. The results indicated a high-pressure level of 479.56 kPa on 12 cm2 area during long periods of time.


Desarrollo de filtro Wavelet Symlet 6 para el Análisis de Señales Encefalográficas

Sandra C. Chacha-Quille, Manuel R. Sagbay-Asitimbay, Bueno-Palomeque Freddy L, Lema-Condo Efrén L.


The work shows the implementation of a wavelet filter Symlet 6 family for analysis or decomposition of brain waves (Delta, Theta, Alpha, Beta y Gamma), the filter was performed using the technique of sub-bands or digital filters, the algorithm was developed in Matlab where youcan see the results.wavlet

Análisis de la postura al sentarse utilizando sensores de fuerza

Carlos A. Tamay-Crespo, Richard M. Ramos-Tituana Freddy L. Bueno-Palomeque y Luis J. Serpa-Andrade.


The risk, that remaining in a sitting position for a long period of time, involves is associated with back injuries and ulcers generation. This investigation analyzes the posture of a person who stays sit for long periods of time. We built a system conformed of force sensors to estimate the force that a person applies in this position. Ten persons were tested in a period of time of eight to fifteen minutes. The results show that three people remain in a good posture, while the other seven constantly change their position. This paper proposes an efficient tool to qualify the position of people to expand the ergonomic analysis in the occupational, educational or clinical ambit. presion asiento

Knee-exoskeleton control for gait rehabilitation based on sEMG of trunk muscles

Ana Cecilia Villa-Parra, Denis Delisle-Rodriguez, Thomaz Botelho, Alberto López-Delis, Ricardo Carelli, Anselmo Frizera-Neto, Teodiano Bastos


Controllers for robotic rehabilitation must be adapted to the functional capabilities of users and recognize human-motion intention. Surface electromyography signals (sEMG) are often used as a control command signal due it is one of the most important biological signals which directly reflect the human-motion intention. sEMG signals from lower limb muscles are recorded as primary actor in
locomotion, however, the erector spinae muscle (ES) from trunk also can be used to recognize motor intention related to lower limb movement [1].
This work presents the development of a control system for a knee exoskeleton based on velocity adjustment and motion intention from ES muscle, which can be used in gait rehabilitation. In order to explore trunk muscles to recognize motor activities related to knee motion, a protocol to acquire a database was developed. An acquisition equipment (BrainNet BNT 36) is used to get sEMG signals from healthy subjects (sampling rate of 400 Hz, band-pass filter from 10 to 100 Hz) of the following muscles: rectus femoris, vastus lateralis, biceps femoris, semitendinosus and gastrocnemius, erectus spinae at levels C7, T3, T7, T12 and L4. Artificial neural network, linear discriminant analysis, and support vector machine (using Gaussian kernel) were used as classifiers. As results, was obtained an acceptable accuracy between signals from trunk and lower limb muscles related to the recognition of the following motor tasks: knee-flexion/extension, standing/sitting, walking and rest stand/sit. The sEMG signals are used as controller input signals. Once the motion intention is recognized, the velocity controller adjusts the knee movement according to both: user torque and an adjustable gain related to the sensibility of the movement based on a hyperbolic function. Preliminary results in passive knee rehabilitation therapy show a good performance of the controller. The assist level of the exoskeleton can be adjusted until the user’s motion intention to track a desired trajectory and to stop it when the user decides.

Non-supervised Feature Selection: Evaluation in a BCI for Single-Trial Recognition of Gait Preparation/Stop

Denis Delisle-Rodriguez, Ana Cecilia Villa-Parra, Alberto López-Delis, Anselmo Frizera-Neto, Eduardo Rocon and Teodiano Freire-Bastos


Is presented a non-supervised method for feature selection based on similarity index, which is applied in a brain-computer interface (BCI) to recognize gait preparation/stops. Maximal information compression index is here used to obtain redundancies, while representation entropy value is employed to find the feature vectors with high entropy. EEG signals of six subjects were acquired on the primary cortex during walking, in order to evaluate this approach in a BCI. The maximum accuracy was 55 and 85 % to recognize gait preparation/stops, respectively. Thus, this method can be used in a BCI to improve the time delay during dimensionality reduction.

Towards a Wearable Robot for Lower Limb Rehabilitation through Human Motion Intention

Delisle-Rodriguez, A.C. Villa-Parra, A. López-Delis, A. Frizera-Neto, E. Rocon, and T. Freire-Bastos

Analysis of a Mobile System to Register the Kinematic Parameters in Ankle, Knee, and Hip Based in Inertial Sensors

Víctor Flores-Morales, Byron Contreras-Bermeo, Freddy Bueno-Palomeque y Luis Serpa-Andrade.


Understanding the lower-extremity kinematic during daily and sport activities provides important information in order to detect abnormalities in human gait or analyse the execution of different sport techniques. Following this approach, this paper presents a kinematic data collection system of human gait in the lower extremities using six inertial sensors MPU 6050 and a microcontroller ATMEGA328P-PU. Six tests were performed and the angular variation was recorded during the execution. The curves obtained during the tests showed a maximum error of ± 4, ± 1, and -4 degrees at the Yaw, Pitch, and Roll angles respectively. This study proposes a mobile and inexpensive system for detecting the angular variation in reduced speed movements, ideal for goniometric measurement or analyse the techniques in certain sports.

Assessment of Frequency Specific Auditory Steady-State Response Using Amplitude Modulation with 2-order Exponential Envelope

Pablo Cevallos-Larrea, Thobias Pereira, Wagner Santos, Silvana M. Frota, Antonio F. Infantosi, Roberto. M. Ichinose, and Carlos Tierra-Criollo.


This study investigated the performance of Frequency Specific Auditory Steady-State Response (FS-ASSR) detection elicited by the amplitude modulated tone with 2-order exponential envelope (AM2), using objective response detection (ORD) techniques of Spectral F-Test (SFT) and Magnitude Squared Coherence (MSC). ASSRs from 24 normal hearing adults were obtained during binaural multi-tone stimulation of amplitude-modulation (AM) and AM2 at intensities of 60, 45 and 30 dBSPL. The carrier frequencies were 500, 1000, 2000, and 4000 Hz, modulated between 77 and 105 Hz. AM2 achieve FS-ASSR amplitudes higher than AM by 16%, 18% and 12% at 60, 45 and 30 dBSPL, respectively, with a major increase at 500 Hz (22.5%). AMS2PL increased the Detection Rate (DR) up to 8.3% at 500 Hz for 30 dBSPL, which is particularly beneficial for FS-ASSR detection near the hearing threshold. In addition, responses in 1000 and 4000 Hz were consistently increased. The MSC and SFT presented no differences in Detection Rate (DR). False Detection Rate (FDR) was close to 5% for both techniques and tones. Detection times to reach DR over 90% were 3.5 and 4.9 min at 60 and 45 dBSPL, respectively. Further investigation concerning efficient multiple FS-ASSR is still necessary, such as testing subjects with hearing loss.

Anthropometry Measurement Kinematic and Kinetic Bipedal Gait.

Pablo Cevallos-Larrea, Thobias Pereira, Wagner Santos, Silvana M. Frota, Antonio F. Infantosi, Roberto. M. Ichinose, and Carlos Tierra-Criollo.


Biomechanical analysis for different techniques of the full squat

B.F.Peñafiel; B.A. Bravo; D.R. Cabrera; L.A. Belduma


The full squat technique is evaluated through a pattern graphic and by comparing the same exercise in three different styles, looking for similarities for the described path by the bar and comparing the minimum dots of close of the angle formed by the hip and the angle of the knee. The person who best develops the exercise is determined because of their similarity to the pattern graphic.

Computer system for analysis of joints of lower limbs

L. A. Sarmiento-Moscoso; J. L. Ochoa-Ochoa; J. C. Montesdeoca-Contreras; J. A. Morales-Garcia; P. F. Urgilés-Ortiz; J. C. Zambrano-Abad.


Summary is only given; This paper describes a computational method for biomechanical analysis of movement and force exerted by the joints of the lower limbs in the process of running, unlike other methods it is based on the placement of LEDs in each joint and through the acquisition and the digital image processing coordinates of the movement and force of each is obtained. The mathematical process of obtaining the coordinates so the force is detailed in this document, as the process of adapting the camera to take the data. This type of analysis will be used to determine gait patterns and the design of an exoskeleton for paraplegics.


Design, construction and implementation of right biomechanical hand prosthesis

J. Cuzco, M. Quinde, J. Brito, J. Calle , F. Urgilés


This paper presents the results of the processes of design, construction and implementation of abiomechanical prosthesis of right hand, as a first step is performed a study of the anatomy of the handand according to these principles, define the basic movements that want to get into the prosthesis. Then calculated, designed and defined the mechanisms and materials from which will be built the elements of the hand considering the esthetic and ergonomics required for each part. Below, isdesigned and defined the control system the same which is based on signal handling using an optical sensor, this makes the prosthesis does not have in its structure any invasive element that might cause damage to the person who uses it. Finally the prototype is built and the implementation is done on a person with hand amputation and in the corresponding tests are obtained efficient results in relation to the mechanisms, anthropometry and control system.

Knee motion pattern classification from trunk muscle based on sEMG signals

López-Delis, D. Delisle-Rodríguez, A. C. Villa-Parra and T. Bastos-Filho.


A prominent change is being carried out in the fields of rehabilitation and assistive exoskeletons in order to actively aid or restore legged locomotion for individuals suffering from muscular impairments, muscleweakness, neurologic injury, or disabilities that affect the lower limbs. This paper presents a characterization of knee motion patterns from Surface Electromyography (sEMG) signals, measured in the Erector spinae (ES) muscle. Feature extraction (mean absolute value, waveform length and auto-regressive model) and pattern classification methods (Linear Discrimination Analysis, K-Nearest Neighborhood and Support Vector Machine) are applied for recognition of eight-movement classes. Additionally, several channels setup are analyzed to obtain a suitable electrodes array. The results were evaluated based on signals measured from lower limb using quantitative metric such as error rate, sensitivity, specificity and predictive positive value. A high accuracy (> 95%) was obtained, which suggest that it is possible to detect the knee motion intention from ES muscle, as well as to reduce the electrode number (from 2 to 3 channels) to obtain an optimal electrodes array. This implementation can be applied for myoelectric control of lower limb active exoskeletons.

Design of active orthoses for a robotic gait rehabilitation system



An active orthosis (AO) is a robotic device that assists both human gait and rehabilitation therapy. This work proposes portable AOs, one for the knee joint and another for the ankle joint. Both AOs will be used to complete a robotic system that improves gait rehabilitation. The requirements for actuator selection, the biomechanical considerations during the AO design, the finite element method, and a control approach based on electroencephalographic and surface electromyographic signals are reviewed. This work contributes to the design of AOs for users with foot drop and knee flexion impairment. However, the potential of the proposed AOs to be part of a robotic gait rehabilitation system that improves the quality of life of stroke survivors requires further investigation.

An Exploration of the Erector Spinae Muscle for Knee Exoskeleton Control

Delisle-Rodriguez, D. ; Villa-Parra, A. C. ; Bastos, T. ; Frizera-Neto, A. ; López-Delis, A.


Lumbar erector spinae muscle has been little ex- plored for knee exoskeleton control through sEMG signals, which could improves the onset and offset of motion. In this study, a simultaneous sEMG record was obtained in three movements routine (knee extension-flexion, stand-up from seated position and seat-down from up position) from five trunk levels, and five muscles of the leg. sEMG signals were smoothed to obtain the envelope through the captured sample entropy method, which can be used to detect the onset/offset through an adaptive threshold value. The onset/offset related to knee motion was obtained on trunk muscles, during knee extension-flexion, stand-up and sit- down activities, which is suitable for knee exoskeleton control.


Towards a Robotic Knee Exoskeleton Control Based on Human Motion Intention through EEG and sEMG signals

VILLA, A. C. ; DELISLE-RODRÍGUEZ, D. ; López-Delis, A. ; BASTOS-FILHO, T. ; SAGARÓ, R. ; Frizera-Neto, A.


The integration of lower limb exoskeletons with robotic walkers allows obtaining a system to improve mobility and security during gait rehabilitation. In this work, the evaluation of human motion intention (HMI) based on electroencephalogram (EEG) and surface electromyography (sEMG) signals are analyzed for a knee exoskeleton control as a preliminary study for gait neuro-rehabilitation with a hybrid robotic system. This system consists of the knee exoskeleton H2 and the UFES’s Smart Walker, which are used to restore the neuromotor control function of subjects with neural injuries. An experimental protocol was developed to identify patterns to control the exoskeleton in accordance with the HMI-based on EEG/sEMG. The EEG and sEMG signals are recorded during the following activities: stand-up/sit-down and knee flexion/extension. HMI is analyzed through both event-related desynchronization/synchronization (ERD/ERS) and slow cortical potential, as well as the myoelectric pattern classification related to lower limb. The feature extraction from sEMG signals is based on vector combinations in time and frequency domain which are used for a pattern classification stage trough an artificial neural network with Levenberg Marquadt training algorithm and support vector machine. Preliminary results shown that a combination of EEG/sEMG signals can be used to define a control strategy for the robotic system.




Knee analysis to determine physical parameters on structures Exoskeleton

Víctor Hugo Pulla Sanchez; Patricio Fernando Urgiles Ortiz


This paper presents a biodynamic analysis of knee in the time-domain by trigonometric methods, we consider relevant aspects of gait analysis, also the sit-to-stand movement that consist in lift the body from a chair, and finally the consequences that produce linear and angular movements in this joint. We validate our model with simulations and experimental results, so that can add movement to an exoskeleton structure in analysis region with parameters power, torque, speed and tenacity. The percentage error from model takes as reference the simulation results, this part have statistical data that provide anthropometric measurements and aim to give approximate results for individuals who can adopt this type of active structures.


Knee torque analysis to implement an exoskeleton

Maria Augusta Flores Rivera; Bertha Catalina Punin Sigcha; Pedro Alcibiades Jara Maldonado; Luis Fernando Fernandez; Patricio Javier Guaraca Medina; Luis Alfredo Calle Arevalo; Patricio Fernando Urgiles Ortiz.


This document presents a mathematical and experimental analysis by the Lagrange equations and with a electrogoniometer, which allows us to obtain the trajectories realized by the knee, by the angular displacing between: hip, knee and ankle; with this and applying mathematical concepts, it is possible todetermine the torque applied to the knee while getting up.


Analysis of torque and power supported by the Hip during a change of sitting position to standing and walking cycle

Luis Alfredo Calle Arévalo; Patricio Javier Guaraca Medina; Patricio Fernando Urgiles Ortiz


In the present study we analyze the speed, acceleration, torque, boiler power during a complete phase of human walking and of the change of state: from sitting position to standing position. As a part of the experimentation methodology, we use artificial vision and with this we capture the points located in: hip, knee and ankle, these are states join by segments, to finally obtain the variation of the angle producedby each segment relative to the vertical.

Fecha de Publicación: Agosto 2014

Analysis of torque and power supported by the Hip during a change of sitting position to standing and walking cycle

Luis Alfredo Calle Arévalo; Patricio Javier Guaraca Medina; Patricio Fernando Urgiles Ortiz


In the present study we analyze the speed, acceleration, torque, boiler power during a complete phase of human walking and of the change of state: from sitting position to standing position. As a part of the experimentation methodology, we use artificial vision and with this we capture the points located in: hip, knee and ankle, these are states join by segments, to finally obtain the variation of the angle producedby each segment relative to the vertical.


Effect of varying femoral anteversion angle on the stress distribution in dysplastic hip joint

Freddy L. Bueno-Palomeque, Carlos J. Cortés-Rodríguez y Carlos D. García-Sarmiento


Residual hip dysplasia is the biggest cause of osteoarthrosis and its treatment in young people and adults often requires surgery. We propose a customized virtual surgery scenario to estimate the stress distribution on the hip joint, considering the planned operative procedure, and different articular rotations to change the femoral anteversion angle.We simulated the stance phase of a gait cycle using finite elements analysis on a three dimensional model constructed from computerized tomography images of a patient with residual dysplasia. The maximum effective stress post-operative over the femoral head was reduced by 20.2% and the contact pressure over the femoral articular cartilage by 42% at the point of greatest load in the gait cycle. We rotated the femoral anteversion angle from 40° to 10°, finding a better biomechanical response between 12° and 16°. The results indicated an excessive load over the pathological joint and an important reduction of the maximum stress over the post-operative model as an outcome of the joint relocation.


Analysis for development of biosignals acquisition manual for a biomedical engineering laboratory

J. C. Montesdeoca-Contrerasa; A. C. Villa-Parra; F.L. Bueno-Palomeque


Biosignals acquisition is a fundamental task in biomedical engineering applications. A correct acquisition and a proper method for interpreting the data acquired are required in order to design control devices or monitoring systems. This paper presents the design of a manual for biosignals acquisition (EMG, EEG, EOG and ECG) using the Biopac MP 45 for theoretical and experimental lessons as a part of the activities of a biomedical engineering laboratory. In order to recognize patterns and variations in the biosignals, the lessons include mathematical analysis for EEG and EMG signals and temporal analysis for EOG and ECG signals. Also, a database to perform postprocessing work are acquired. The results obtained with the implementation of these lessons by undergraduate students were satisfactory.


Development of an EEG and sEMG Wireless System for a Robotic Walker



This work proposes the development of an electroencephalography (EEG) and surface electromyography (sEMG) wireless system for a robotic walker. The goal is to validate its performance at the front-end channels through steady state visually evoked potential (SSVEP) and events-related desynchronization/ synchronization (ERD/ERS). The frequencies employed in the SSVEP are captured on the occipital region through FP1-O1 EEG electrodes. Furthermore, ERD/ERS pattern are obtained on the cortical motor areas through C3-FZ and C4-FZ electrodes during button movements with index finger of the right hand. In addition, the myoelectric activity (sEMG) of the peroneus longus muscle is obtained during ankle flexion-extensions. The front-end designed can be used to obtain motor patterns from the brain and muscle activities.


Control System for an Active AFO to Assist Ankle Dorsiflexion Movements in Swing Phase of Gait

VILLA, A. C. ; PATINO, D. ; Zequera, M. ; FREIRE-BASTOS, T.


An inadequate dorsiflexion movement during the swing phase of gait is a common disability in patients after a stroke accident and affects the normal gait. To assist this biomechanical impairment, orthopedically doctors prescribe ankle foot orthosis (AFO), nevertheless, this mechanical support in many occasions is not successful. This paper presents a state feedback controller for an active AFO for advancing the foot in the swing phase to a neutral position with a DC motor. To determine the torque required to assist the ankle in the sagittal plane, a model of the system legfoot-ankle is developed. Also a mechanical design of the AFO is presented. Results indicate that the control system discussed can be used for an active AFO in cases of the drop foot assistance for rehabilitation applications.


Proposal of an Assisted-Motion System for Gait Rehabilitation



This work proposes the development of a system to assist the gait rehabilitation, composed of a smart walker and a lower-limb active orthosis. The system is controlled by brain signals (EEG), surface myoelectric signals (sEMG), inertial, force and distance sensors. The main goal is to obtain an innovative robotic system that controls the human joint motion in different phases of the gait, that can adapt for different joint impedances during gait cycle, and providing robustness when using brain patterns from the user’s motor intention. The proposed system can be adjusted to situations of fatigue and the evolution of the user’s rehabilitation.


Creation of the Biomedical Engineering Research Group GIIB-UPS at the Salesian Polytechnic University

A.C. Villa; F. Urgilés


The integration of engineering and medicine in recent years has led to the development of technological innovations in the health field, that is why this area has been declared emergent in many countries and it has become a basic research discipline. In this paper we describe the experience in the academic support of the Electronic Engineering Department at the Salesian Polytechnic University of Cuenca for development projects of biomedical engineering from 2001 in order to establish guidelines to begin with the research group GIIB-UPS. The main objectives are to enrich the teaching and learning method in Biomedical Engineering, to strengthen the social appropriation of knowledge of the results of research around biomedical engineering in the University and to establish guidelines to begin the process of forming the first research group in this field in Ecuador. Based on results to date, we conclude that biomedical engineering education must ensure a positive work environment in which students will develop social sensibility with professional ethic and learn about the importance in their profession of multidisciplinary cooperation with professionals in the biomedical field. The proper progress of a research group requires time and planning for research training by lecturers and students.

Fecha de publicación: Noviembre de 2012



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