RESUMEN
Hardness, dimensions, and location of biological tissues are important parameters for electronic palpation protocols with standardized performance. This study presents a novel fluid-type tactile sensor able to measure size and depth of heterogeneous substances in elastic bodies. The new sensor is very simple and can be easily fabricated. It consists of an image sensor, LED lights, and a touchpad filled with translucent water. The intensity field of the light traveling in the touchpad is analyzed to estimate the touchpad shape which conforms to the shape of an object in contact. The use of the new sensor for measuring size and depth of heterogeneous substances inside elastic bodies as well as hardness of elastic bodies is illustrated. Results obtained for breast cancer dummies demonstrate the effectiveness of the proposed approach.
Asunto(s)
Palpación/instrumentación , Tacto , Neoplasias de la Mama/diagnóstico , Diseño de Equipo , Femenino , Humanos , Modelos Teóricos , Visión OcularRESUMEN
The main challenges of designing devices for paraplegic walking can be summarized into three groups, stability and comfort, high efficiency or low energy consumption, dimensions and weight. A new economical device for people with paraplegia which tackles all problems of the three groups is introduced in this paper. The main idea of this device is based on HALO mechanism. HALO is compact passive medial hip joint orthosis with contralateral hip and ankle linkage, which keeps the feet always parallel to the ground and assists swinging the leg. The medial hip joint is equipped with one actuator in the new design and the new orthosis is called @halo. Due to this update, we can achieve more stable and smoother walking patterns with decreased energy consumption of the users, yet maintain its compact and lightweight features. It is proven by the results from preliminary experiments with able-bodied subjects during which the same device with and without actuator was evaluated. Waddling and excessive vertical elevation of the center of gravity were decreased by 40% with significantly smaller standard deviations in case of the active orthosis. There was 52% less energy spent by the user wearing @halo which was calculated from the vertical excursion difference. There was measured 38.5% bigger impulse in crutches while using passive orthosis. The new @halo device is the first active orthosis for lower limbs with just one actuated degree of freedom for users with paraplegia.
Asunto(s)
Extremidad Inferior/fisiopatología , Aparatos Ortopédicos , Paraplejía/rehabilitación , Rango del Movimiento Articular/fisiología , Adulto , Tobillo/fisiopatología , Diseño de Equipo , Cadera/fisiopatología , Humanos , Paraplejía/fisiopatología , Adulto JovenRESUMEN
A hip-knee-ankle-foot orthotic system called `HALO'(Hip and Ankle Linked Orthosis) for paraplegic walking has been developed in our previous study. Each ankle joint of the HALO system is linked with a medial single joint via a wire which allows both feet of the orthosis to stay always parallel to the floor during walking and assists swinging the leg. The tests of the HALO system demonstrated that it allows smoother walking and easy don/doff. In order to improve further the characteristics of the previous design, we started a new project called pHALO aiming at further reducing of the energy expenditure during walking. As a difference from the previous solution where ankle joints were restrained, the new solution will incorporate two actuators to control the ankle joints angles. As an intermediate step from the development of the pHALO system, in this study we added to the existing system a feedback PI controller to control the ankle joint angle of the right foot in the push-off phase and conducted an experiment to evaluate the effect of the new design on the walking patterns and energy efficiency. The results showed longer stride length, faster gait speed, smaller variation of the CoG, and less energy consumption.
Asunto(s)
Marcha , Tobillo , Articulación del Tobillo , Fenómenos Biomecánicos , Diseño de Equipo , Humanos , Aparatos Ortopédicos , CaminataRESUMEN
A new method is proposed to estimate the contact region between a sensor and an object using a deformable tactile sensor. The sensor consists of a charge-coupled device (CCD) camera, light-emitting diode (LED) lights and a deformable touchpad. The sensor can obtain a variety of tactile information, such as the contact region, multi-axis contact force, slippage, shape, position and orientation of an object in contact with the touchpad. The proposed method is based on the movements of dots printed on the surface of the touchpad and classifies the contact state of dots into three types--A non-contacting dot, a sticking dot and a slipping dot. Considering the movements of the dots with noise and errors, equations are formulated to discriminate between the contacting dots and the non-contacting dots. A set of the contacting dots discriminated by the formulated equations can construct the contact region. Next, a method is developed to detect the dots in images of the surface of the touchpad captured by the CCD camera. A method to assign numbers to dots for calculating the displacements of the dots is also proposed. Finally, the proposed methods are validated by experimental results.
Asunto(s)
Telemetría/instrumentación , Tacto , Visión Ocular , Procesamiento de Imagen Asistido por ComputadorRESUMEN
Several types of hip-knee-ankle-foot orthotic systems have been proposed for paraplegic walking during these decades. Hip and ankle linked orthosis (HALO) is compact one in those orthoses, which seeks to achieve a smoother-movement and user-easiness on its don/doff in paraplegic walking. The idea of HALO is to link two ankle joints with medial single joint via wires so that the orthosis keeps both feet always parallel to the floor while walking and assist the swinging of the leg. So as to reduce the consumption energy of HALO walking, we have introduced two actuators to control the ankle-joints angles in this paper. The actuators placed at hip joint in HALO allow the orthosis to have more degree-of-freedom and are able to provide a propulsive force the coupled user-orthosis system. The results of preliminary experiments with normal subjects show that the users can walk smoother and the proposed orthotic system will be able to reduce the users' consumption energy while walking.
Asunto(s)
Marcha/fisiología , Aparatos Ortopédicos , Paraplejía/rehabilitación , Rango del Movimiento Articular/fisiología , Adulto , Tobillo , Fenómenos Biomecánicos , Diseño de Equipo , Cadera , Humanos , Equilibrio Postural , Adulto JovenRESUMEN
To design a powered assistive orthosis for human walking, we have simulated walking motion with an orthosis. The model dynamics of the coupled human-orthosis is represented by a 10-rigid-link system. In this model there exist rotational joints at lumbar, both thighs and both legs for orthosis, and each joints are controlled by a couple of central pattern generators (CPG) which imitates neuronal system in the spinal cord of mammals. The CPG controller modeled by 18 oscillators which have the sensory feedbacks and generates the joint torques to move the skeletal model of the coupled human-orthosis. This means that we use five actuators for controlling orthosis in the both of sagittal and frontal plane. The parameters of the CPG and the connecting gains are optimized by using a genetic algorithm. We have achieved the successful simulation of stable walking against disturbances with this model. The simulation results indicate the possibility of a practical assistive orthosis with five active joints for stable walking.
Asunto(s)
Diseño de Equipo/métodos , Pierna/fisiología , Sistemas Hombre-Máquina , Modelos Biológicos , Aparatos Ortopédicos , Robótica/instrumentación , Caminata/fisiología , Simulación por Computador , Diseño Asistido por Computadora , Análisis de Falla de Equipo , Marcha/fisiología , HumanosRESUMEN
This paper proposes a method for enhancing the robustness of the central pattern generator (CPG)-based three-dimensional (3D) neuromusculoskeletal walking controller. The CPG has been successfully applied to walking controllers and controllers for walking robots. However, the robustness of walking motion with the CPG-based controller is not sufficient, especially when subjected to external forces or environmental variations. To achieve a realistic and stable walking motion of the controller, we propose the use of an attracting controller in parallel with the CPG-based controller. The robustness of the proposed controller is confirmed through simulation results.
Asunto(s)
Simulación por Computador , Modelos Neurológicos , Redes Neurales de la Computación , Caminata/fisiología , HumanosRESUMEN
Recently, bilateral movement training based on robot-assisted rehabilitation systems has been attracting a lot of attention as a post-stroke motor rehabilitation protocol. Since humans generate coordinated motions based on their motor and sensory systems, investigation of the innate properties of human motor or sensory systems may provide insight into planning of effective bilateral movement training. In this study, we investigate the effects of proprioception and handedness on the movement of the contra-lateral upper limb, under both active and passive guidance conditions of the robot manipulators. Active and passive guidance-reproduction based bimanual tasks were used in this study; in these the subject is asked to hold both the right and left knobs installed at the end-effectors of two robot manipulators. The results indicate that better reproducing performance was obtained when the proprioceptive input was acquired from the active guidance condition.
Asunto(s)
Lateralidad Funcional , Propiocepción , HumanosRESUMEN
This study proposes a new method to automatically estimate a person's mental workload (MWL) using a specific type of eye movements called saccadic intrusions (SI). Previously, the most accurate existing method to estimate MWL was the pupil diameter measure [1]. However, pupil diameter is not practical in a vehicle driving environment because it is overly sensitive to brightness changes. A new method should be independent from environment brightness changes, robust in most driving environments, and accurately reflect MWL. This study used SI as an indicator of MWL because eye movements, including SI, are independent from brightness changes. SI are a specific type of eye-gaze deviations. SI are known to be closely related to cognitive activities [2], [3]. This means that SI may be also closely related to MWL. Eye movements were recorded using a non-intrusive eye tracking camera, located 550 mm away from a participant. Participants were instructed to move their eye gaze to examine a highway driving scenery picture. In the data set of the recorded eye movements, our new algorithm detected SI and quantified SI behavior into a SI measure. Participants were also engaged in a secondary N-back task. The N-back task is a popular task used in cognitive sciences to systematically control a MWL level of participants. In our results, all 14 participants exhibited more SI eye movements when their MWL level was high compared to when their MWL level was low. Moreover, our results showed that the SI measure was a more accurate measure of MWL than the pupil diameter measure. This finding indicates that MWL of the person can be estimated by observation of SI eye movements. This new method has a wide range of applications. One of them is to predict a person's MWL, thus predicting when a person is capable of driving a vehicle in a safe or dangerous manner.
Asunto(s)
Movimientos Sacádicos , Análisis y Desempeño de Tareas , Adulto , Algoritmos , HumanosRESUMEN
Functional electrical stimulation (FES) is useful to improve the gait of patients with peroneal nerve palsy or spastic hemiparesis after stroke. So as to apply FES to such patients, we have to have estimators for detecting the timing of phase switching in walking motion. We designed a wearable device for state estimating of walking and functional electrical stimulation. We consider the implementation of artificial neural network (ANN) into the device, and propose a method for supervised learning of the ANN. Two experiments have been conducted to show the effectiveness of the wearable device. The accuracy of estimating the timing for FES is good enough for the practical application.
Asunto(s)
Vestuario , Diagnóstico por Computador/instrumentación , Terapia por Estimulación Eléctrica/instrumentación , Trastornos Neurológicos de la Marcha/diagnóstico , Trastornos Neurológicos de la Marcha/rehabilitación , Monitoreo Ambulatorio/instrumentación , Caminata , Diagnóstico por Computador/métodos , Diseño de Equipo , Análisis de Falla de Equipo , Humanos , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
This paper considers the analysis of dynamics of human operators when the environmental dynamics changes. When an operator conducts a task with his arm, the adaptation on his manipulating dynamics occurs according to the dynamics of environment. We assume that the adaptation has a certain relation to the cognition of the change of environmental dynamics. To confirm the assumption, we have planned the experiment in which subjects are required to perform several kinds of tracking tasks. It is shown in the experiment that the dynamics of manipulation correlates with the cognition of the change of environmental dynamics.
Asunto(s)
Adaptación Fisiológica/fisiología , Brazo/fisiología , Cognición/fisiología , Retroalimentación/fisiología , Modelos Biológicos , Movimiento/fisiología , Desempeño Psicomotor/fisiología , Algoritmos , Simulación por Computador , HumanosRESUMEN
This paper reports on the development of a new lower limb prosthesis that can change its volume and hardness based on the users requirements. The size and viscosity of several Magneto-Rheological fluid filled bags, fixed on the inner side of the socket is changed, in order to vary the socket properties. TSB (total surface bearing) sockets have been most selling ones during these two decades. From the user's point of view, it is excellent in this type of sockets that the weight of user is supported with the entire socket surface. However, it is impossible to cope with the volume change of the user's stump. Experimental results show that the performance of the developed MR socket is better than the conventional TSB sockets because the MR socket is controllable in the size and viscosity.
Asunto(s)
Miembros Artificiales , Articulación de la Rodilla/fisiopatología , Extremidad Inferior , Magnetismo/instrumentación , Ajuste de Prótesis/instrumentación , Ajuste de Prótesis/métodos , Reología/instrumentación , Diseño de Equipo , Análisis de Falla de Equipo , Humanos , PresiónRESUMEN
As per present social needs, assisting machines are very much needed for persons of advanced age. We analyzed and developed a fitness apparatus suitable for meeting the requirement of elderly people. The proposed apparatus consists of a rowing machine and Functional Electrical Stimulation (FES), that can be used to exercise every muscle of a person of advanced age. The rowing mechanism was actually developed to train rowers and can train the legs and upper body parts most effectively. Move over FES can assist the exercise of the legs by using surface electrical stimulation. An experiment was conducted and the results prove that the developed apparatus can train the muscles of the person of advanced age effectively and can compensate exercise shortage.
Asunto(s)
Terapia por Ejercicio/instrumentación , Aptitud Física , Anciano , Estimulación Eléctrica , Humanos , Fuerza MuscularRESUMEN
The restoration of motor functions of patients with spinal cord injury (SCI) is one of important subjects for study. For this purpose, methods of functional neuromuscular stimulation (FNS) have been investigated in medical science and practice during these three decades. However, we have not achieved complete restoration of motor functions in SCI patients. On the other hand, we have achieved useful devices in human-scaled transportation by using power assist technology. Thus, applying power assist technology to the problem of restoring motor functions is one of possible solutions and sounds practical. In this paper, we propose a new hybrid system to combine power assist technology and FNS for restoring motor functions of lower extremity in SCI patients. Both powered orthosis and FNS are used to generate and control the joints moments of lower extremity in the proposed hybrid system. The main role of powered orthosis to compensate the joints moments generated by FNS and to enhance the controllability of FNS with the actuators. The proposed hybrid control system has been experimentally evaluated in gait motions by measuring the angle trajectories and generated moments around the knee and hip joints in the cases when only actuators are used and both FNS and actuators of the orthosis are used. The results prove that the control method for the hybrid system is useful to restore motor functions of lower extremity in SCI patients.
Asunto(s)
Marcha/fisiología , Unión Neuromuscular/fisiología , Aparatos Ortopédicos , Caminata/fisiología , Adulto , Aluminio , Estimulación Eléctrica , Diseño de Equipo , Humanos , Articulaciones/fisiología , Soporte de PesoRESUMEN
Joint contractures decrease the patient's ability to walk, but usually other parts of the body compensate the affected joint contractures. When we restore the gait performance in paraplegic patients by means of functional electrical stimulation, however, we cannot expect complications of compensation. A computer simulation was done to clarify how the contractures affect the gait pattern when no complications of compensation were expected. A seven-segment link mechanical model was used for simulation of human walking in the sagittal plane. In turn, using a personal computer stance and swing-leg joint contractures of the ankle, knee, and/or hip were simulated. When stance-leg contracture was simulated, step length became short with increasing hip flexion contracture. The trunk was tilted backward during knee flexion or ankle plantarflexion contracture simulation. When the swing-leg contracture was simulated, step length became short with increasing knee flexion contracture. We found that hip or knee flexion contracture of < or = 15 degrees, or ankle plantarflexion contracture of < 0 degrees was required to maintain positive step length and forward movement of the center of gravity. These findings suggest that 15 degrees of hip and knee flexion contracture, and 0 degrees of ankle plantarflexion contracture are critical when gait restoration is performed by functional electrical stimulation.