Pub Date : 2018-08-01DOI: 10.1109/BIOROB.2018.8487966
Valentina Gregori, B. Caputo, A. Gijsberts
The application of machine learning to recognize hand movements from surface electromyography has led to promising academic results. Unfortunately, it has proven difficult to translate these results in better control methods for the end-users of upper-limb prostheses. Recent studies have pointed out that common offline performance metrics, such as classification accuracy, are not correlated with real controllability of the prosthesis. In this paper, we investigate the cause that learned models start to fail when applied outside the constrained laboratory setting. We performed several analyses at the hand of a dedicated data acquisition composed of a typical academic training session in the first phase and a set of activities of daily living in a home setting afterwards. Our analysis confirms that a model trained in the former setting performs poorly when applied in a home environment. The cause for this degradation is that the distribution of myoelectric data changes between both settings, thus violating the typical assumption in statistical learning theory that train and test data come from the same distribution. This problem persists even when adding data acquired in some home activities to classify others. Our result not only confirms the limited importance of offline performance metrics for real prosthesis usability, but also highlights the difficulties machine learning based approaches will need to overcome to become practically relevant.
{"title":"The Difficulty of Recognizing Grasps from sEMG during Activities of Daily Living","authors":"Valentina Gregori, B. Caputo, A. Gijsberts","doi":"10.1109/BIOROB.2018.8487966","DOIUrl":"https://doi.org/10.1109/BIOROB.2018.8487966","url":null,"abstract":"The application of machine learning to recognize hand movements from surface electromyography has led to promising academic results. Unfortunately, it has proven difficult to translate these results in better control methods for the end-users of upper-limb prostheses. Recent studies have pointed out that common offline performance metrics, such as classification accuracy, are not correlated with real controllability of the prosthesis. In this paper, we investigate the cause that learned models start to fail when applied outside the constrained laboratory setting. We performed several analyses at the hand of a dedicated data acquisition composed of a typical academic training session in the first phase and a set of activities of daily living in a home setting afterwards. Our analysis confirms that a model trained in the former setting performs poorly when applied in a home environment. The cause for this degradation is that the distribution of myoelectric data changes between both settings, thus violating the typical assumption in statistical learning theory that train and test data come from the same distribution. This problem persists even when adding data acquired in some home activities to classify others. Our result not only confirms the limited importance of offline performance metrics for real prosthesis usability, but also highlights the difficulties machine learning based approaches will need to overcome to become practically relevant.","PeriodicalId":382522,"journal":{"name":"2018 7th IEEE International Conference on Biomedical Robotics and Biomechatronics (Biorob)","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123130427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-08-01DOI: 10.1109/BIOROB.2018.8488778
Kevin Stein, K. Mombaur
The estimation of acting joint torques and ground reaction forces is of particular interest for the analysis and training of athletic human motions. Modern IMU-based motion capture systems can record the kinematics of motions without the constraint of a fixed capture volume but with a lower accuracy when compared to marker-based systems, however they can give no information about the underlying dynamics. We propose a general approach that allows us to analyze such motion recordings for which external ground reaction force measurements are not possible. To achieve this we use dynamically-consistent optimization to generate a physically valid least-squares fit of a dynamic model of the subject to the recorded motion. We demonstrate the method by fitting and analyzing a cartwheel motion. The resulting joint torques allow us to understand how the different joints are actuated throughout the motion and reconstructed contact forces give insight about the interaction with the environment. Calculation of the forces and torques are of great value during training of athletic motions both to improve technique and to prevent injury. Additionally we can estimate the deviation between the measurement and the physically valid fit.
{"title":"Optimization-Based Analysis of a Cartwheel","authors":"Kevin Stein, K. Mombaur","doi":"10.1109/BIOROB.2018.8488778","DOIUrl":"https://doi.org/10.1109/BIOROB.2018.8488778","url":null,"abstract":"The estimation of acting joint torques and ground reaction forces is of particular interest for the analysis and training of athletic human motions. Modern IMU-based motion capture systems can record the kinematics of motions without the constraint of a fixed capture volume but with a lower accuracy when compared to marker-based systems, however they can give no information about the underlying dynamics. We propose a general approach that allows us to analyze such motion recordings for which external ground reaction force measurements are not possible. To achieve this we use dynamically-consistent optimization to generate a physically valid least-squares fit of a dynamic model of the subject to the recorded motion. We demonstrate the method by fitting and analyzing a cartwheel motion. The resulting joint torques allow us to understand how the different joints are actuated throughout the motion and reconstructed contact forces give insight about the interaction with the environment. Calculation of the forces and torques are of great value during training of athletic motions both to improve technique and to prevent injury. Additionally we can estimate the deviation between the measurement and the physically valid fit.","PeriodicalId":382522,"journal":{"name":"2018 7th IEEE International Conference on Biomedical Robotics and Biomechatronics (Biorob)","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114233209","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-08-01DOI: 10.1109/BIOROB.2018.8487633
Kiyoung Kim, H. Woo, Jungwook Suh
This paper deals with the design, modelling, fabrication, and experiments of a novel continuum robot that can be used for cardiovascular interventions. In this paper, a new design of bending joints of the continuum robot and its kinematical modelling are proposed. The bending joints of the proposed robot are designed to be easy to miniaturize and have a wide motion range. The continuum robot consists of an inner guide and an outer guide, each having two degrees of freedom (DOF). The 2DOF bending joints are driven by antagonistic actuation and the actuation part of the continuum robot is implemented to control the stiffness of the bending joints. When the pretensions of the cables of the bending joints are adjusted, the structural stiffness of the bending joints can be controlled. In this paper, the entire system of the continuum robot has been implemented and the basic performance of the proposed continuum robot has been verified. The proposed robot was confirmed to be bent actively in the S-shape curve.
{"title":"Design and Evaluation of a Continuum Robot with Discreted link joints for Cardiovascular Interventions","authors":"Kiyoung Kim, H. Woo, Jungwook Suh","doi":"10.1109/BIOROB.2018.8487633","DOIUrl":"https://doi.org/10.1109/BIOROB.2018.8487633","url":null,"abstract":"This paper deals with the design, modelling, fabrication, and experiments of a novel continuum robot that can be used for cardiovascular interventions. In this paper, a new design of bending joints of the continuum robot and its kinematical modelling are proposed. The bending joints of the proposed robot are designed to be easy to miniaturize and have a wide motion range. The continuum robot consists of an inner guide and an outer guide, each having two degrees of freedom (DOF). The 2DOF bending joints are driven by antagonistic actuation and the actuation part of the continuum robot is implemented to control the stiffness of the bending joints. When the pretensions of the cables of the bending joints are adjusted, the structural stiffness of the bending joints can be controlled. In this paper, the entire system of the continuum robot has been implemented and the basic performance of the proposed continuum robot has been verified. The proposed robot was confirmed to be bent actively in the S-shape curve.","PeriodicalId":382522,"journal":{"name":"2018 7th IEEE International Conference on Biomedical Robotics and Biomechatronics (Biorob)","volume":"58 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120994069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-08-01DOI: 10.1109/BIOROB.2018.8487903
Jinwon Chung, Roman Heimgartner, Ciarán T. O’Neill, Nathan S. Phipps, C. Walsh
In this paper, we present the design and characterization of the ExoBoot, a soft inflatable robotic boot for assisting ankle plantarflexion during walking. The ExoBoot integrates a soft textile-based actuator and an IMU sensor into a textile boot, making it low-profile and lightweight. The inflatable actuator generates assistive plantarflexion torque when pressurized by bending on top of the boot. We characterize the torque generated by the ExoBoot at various pressures and ankle angles, achieving a maximum torque of 39 Nm at 483 kPa (70 psi) and 60 degrees ankle angle. In order to evaluate the performance of the ExoBoot during walking, a pilot study with one healthy subject was conducted. Actuation is triggered by an open loop pressure controller, based on the ankle angular velocity measured by an IMU, using high flow rate solenoid valves. At the peak of active assistance, pressure in the actuator reaches 75% of the supply pressure, and maximum torque applied on the ankle is estimated to be 23 Nm. These results demonstrate potential for the ExoBoot to reduce the metabolic cost of walking.
{"title":"ExoBoot, a Soft Inflatable Robotic Boot to Assist Ankle During Walking: Design, Characterization and Preliminary Tests","authors":"Jinwon Chung, Roman Heimgartner, Ciarán T. O’Neill, Nathan S. Phipps, C. Walsh","doi":"10.1109/BIOROB.2018.8487903","DOIUrl":"https://doi.org/10.1109/BIOROB.2018.8487903","url":null,"abstract":"In this paper, we present the design and characterization of the ExoBoot, a soft inflatable robotic boot for assisting ankle plantarflexion during walking. The ExoBoot integrates a soft textile-based actuator and an IMU sensor into a textile boot, making it low-profile and lightweight. The inflatable actuator generates assistive plantarflexion torque when pressurized by bending on top of the boot. We characterize the torque generated by the ExoBoot at various pressures and ankle angles, achieving a maximum torque of 39 Nm at 483 kPa (70 psi) and 60 degrees ankle angle. In order to evaluate the performance of the ExoBoot during walking, a pilot study with one healthy subject was conducted. Actuation is triggered by an open loop pressure controller, based on the ankle angular velocity measured by an IMU, using high flow rate solenoid valves. At the peak of active assistance, pressure in the actuator reaches 75% of the supply pressure, and maximum torque applied on the ankle is estimated to be 23 Nm. These results demonstrate potential for the ExoBoot to reduce the metabolic cost of walking.","PeriodicalId":382522,"journal":{"name":"2018 7th IEEE International Conference on Biomedical Robotics and Biomechatronics (Biorob)","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114284654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-08-01DOI: 10.1109/BIOROB.2018.8487207
R. Djajadiningrat, W. Roozing, N. Tsagarakis
This paper presents the optimisation of explosive jumping motions on a 3-DoF leg prototype. The leg is based on the recently introduced asymmetric compliant actuator scheme, in which a series-elastic main drive is augmented with a parallel adjustable compliant branch with significantly different stiffness and energy storage capacity properties. The leg prototype implements two such actuation configurations, one of which includes a biarticulated branch, and they are compared to conventional series-elastic based actuation. An optimisation problem is formulated to optimise the joint trajectories and elastic element pretension to maximise jumping height. A simulation study demonstrates that the biarticulated configuration yields maximum jumping height, and that it achieves the highest peak joint power. Compared to series-elastic based actuation, the augmented leg jumps 4% higher with a monoarticulated parallel compliance configuration while using less energy, and over 10% higher in biarticulated configuration.
{"title":"Explosive Motions with Compliant Actuation Arrangements in Articulated Robots","authors":"R. Djajadiningrat, W. Roozing, N. Tsagarakis","doi":"10.1109/BIOROB.2018.8487207","DOIUrl":"https://doi.org/10.1109/BIOROB.2018.8487207","url":null,"abstract":"This paper presents the optimisation of explosive jumping motions on a 3-DoF leg prototype. The leg is based on the recently introduced asymmetric compliant actuator scheme, in which a series-elastic main drive is augmented with a parallel adjustable compliant branch with significantly different stiffness and energy storage capacity properties. The leg prototype implements two such actuation configurations, one of which includes a biarticulated branch, and they are compared to conventional series-elastic based actuation. An optimisation problem is formulated to optimise the joint trajectories and elastic element pretension to maximise jumping height. A simulation study demonstrates that the biarticulated configuration yields maximum jumping height, and that it achieves the highest peak joint power. Compared to series-elastic based actuation, the augmented leg jumps 4% higher with a monoarticulated parallel compliance configuration while using less energy, and over 10% higher in biarticulated configuration.","PeriodicalId":382522,"journal":{"name":"2018 7th IEEE International Conference on Biomedical Robotics and Biomechatronics (Biorob)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121869944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-08-01DOI: 10.1109/BIOROB.2018.8487219
Yasuyuki Yamada, A. Kojima, Yutaro Higashi, M. Okui, Taro Nakamura
Pneumatic soft actuators has been developed to improved characteristics, such as operating flexibility, low weight, and high output etc. However, the application range of these artificial muscles has been limited by their fragility, the size of pneumatic source and the system size required to control the position and force. Therefore, this research proposes hollow artificial muscles with air cylinder that is high durability and driven with less air. Furthermore, this actuator control both stiffness and displacement independently as single mechanical element.
{"title":"Hollow Pneumatic Artificial Muscles with Air Cylinder: Improvement for compatibility of high durability and high efficiency","authors":"Yasuyuki Yamada, A. Kojima, Yutaro Higashi, M. Okui, Taro Nakamura","doi":"10.1109/BIOROB.2018.8487219","DOIUrl":"https://doi.org/10.1109/BIOROB.2018.8487219","url":null,"abstract":"Pneumatic soft actuators has been developed to improved characteristics, such as operating flexibility, low weight, and high output etc. However, the application range of these artificial muscles has been limited by their fragility, the size of pneumatic source and the system size required to control the position and force. Therefore, this research proposes hollow artificial muscles with air cylinder that is high durability and driven with less air. Furthermore, this actuator control both stiffness and displacement independently as single mechanical element.","PeriodicalId":382522,"journal":{"name":"2018 7th IEEE International Conference on Biomedical Robotics and Biomechatronics (Biorob)","volume":"211 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133732482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-08-01DOI: 10.1109/BIOROB.2018.8487220
Uriel Martinez-Hernandez, Adrian Rubio Solis, A. Dehghani
In this paper, a strategy for recognition of human walking activities and prediction of gait periods using wearable sensors is presented. First, a Convolutional Neural Network (CNN) is developed for the recognition of three walking activities (level-ground walking, ramp ascent and descent) and recognition of gait periods. Second, a first-order Markov Chain (MC) is employed for the prediction of gait periods, based on the observation of decisions made by the CNN for each walking activity. The validation of the proposed methods is performed using data from three inertial measurement units (IMU) attached to the lower limbs of participants. The results show that the CNN, together with the first-order MC, achieves mean accuracies of 100% and 98.32% for recognition of walking activities and gait periods, respectively. Prediction of gait periods are achieved with mean accuracies of 99.78%, 97.56% and 97.35% during level-ground walking, ramp ascent and descent, respectively. Overall, the benefits of our work for accurate recognition and prediction of walking activity and gait periods, make it a suitable high-level method for the development of intelligent assistive robots.
{"title":"Recognition of Walking Activity and Prediction of Gait Periods with a CNN and First-Order MC Strategy","authors":"Uriel Martinez-Hernandez, Adrian Rubio Solis, A. Dehghani","doi":"10.1109/BIOROB.2018.8487220","DOIUrl":"https://doi.org/10.1109/BIOROB.2018.8487220","url":null,"abstract":"In this paper, a strategy for recognition of human walking activities and prediction of gait periods using wearable sensors is presented. First, a Convolutional Neural Network (CNN) is developed for the recognition of three walking activities (level-ground walking, ramp ascent and descent) and recognition of gait periods. Second, a first-order Markov Chain (MC) is employed for the prediction of gait periods, based on the observation of decisions made by the CNN for each walking activity. The validation of the proposed methods is performed using data from three inertial measurement units (IMU) attached to the lower limbs of participants. The results show that the CNN, together with the first-order MC, achieves mean accuracies of 100% and 98.32% for recognition of walking activities and gait periods, respectively. Prediction of gait periods are achieved with mean accuracies of 99.78%, 97.56% and 97.35% during level-ground walking, ramp ascent and descent, respectively. Overall, the benefits of our work for accurate recognition and prediction of walking activity and gait periods, make it a suitable high-level method for the development of intelligent assistive robots.","PeriodicalId":382522,"journal":{"name":"2018 7th IEEE International Conference on Biomedical Robotics and Biomechatronics (Biorob)","volume":"104 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124742719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-08-01DOI: 10.1109/BIOROB.2018.8488157
Brandon P. R. Edmonds, A. L. Trejos
Mechatronic rehabilitative devices have been proven to provide cost effective solutions to long term physical therapy for patients with musculoskeletal disorders. However, current actuator technologies limit the minimization of the overall size and weight of these devices preventing innovation into unobtrusive wearable form factors that are also effective and comfortable. This study is focused on a recently discovered smart actuator made from flexible nylon thread, which has exhibited a great potential for use in wearable mechatronic devices. This is known as the twisted coiled actuator (TCA) due to the hyper twisting and induced coiling involved in its fabrication process. One of the limiting factors of the TCA, is the thermal activation mechanism, which results in a slow cooling phase and a low working bandwidth. This paper is focused on optimizing an active cooling design using numerical analysis. To do this, a simple pipe geometry was designed and tested using fluid dynamics software. Three off-the-shelf fluidic pumps were simulated using varying tube diameters to find a sufficient cooling rate, a minimum fluid volume, and to select a proper pump for future testing. The results indicate that a global maximum cooling rate exists for each specific pump at a unique tube diameter. Additionally, the speed of cooling was under 500 ms concluding that the pumps tested can sufficiently provide the cooling rates required to assist motion in wearable devices. Furthermore, the process developed here provides quantitative support for the optimal selection of initial design parameters and can be translated to designs using different form factors and fluid properties.
{"title":"Computational Fluid Dynamics Study of a Soft Actuator for Use in Wearable Mechatronic Devices","authors":"Brandon P. R. Edmonds, A. L. Trejos","doi":"10.1109/BIOROB.2018.8488157","DOIUrl":"https://doi.org/10.1109/BIOROB.2018.8488157","url":null,"abstract":"Mechatronic rehabilitative devices have been proven to provide cost effective solutions to long term physical therapy for patients with musculoskeletal disorders. However, current actuator technologies limit the minimization of the overall size and weight of these devices preventing innovation into unobtrusive wearable form factors that are also effective and comfortable. This study is focused on a recently discovered smart actuator made from flexible nylon thread, which has exhibited a great potential for use in wearable mechatronic devices. This is known as the twisted coiled actuator (TCA) due to the hyper twisting and induced coiling involved in its fabrication process. One of the limiting factors of the TCA, is the thermal activation mechanism, which results in a slow cooling phase and a low working bandwidth. This paper is focused on optimizing an active cooling design using numerical analysis. To do this, a simple pipe geometry was designed and tested using fluid dynamics software. Three off-the-shelf fluidic pumps were simulated using varying tube diameters to find a sufficient cooling rate, a minimum fluid volume, and to select a proper pump for future testing. The results indicate that a global maximum cooling rate exists for each specific pump at a unique tube diameter. Additionally, the speed of cooling was under 500 ms concluding that the pumps tested can sufficiently provide the cooling rates required to assist motion in wearable devices. Furthermore, the process developed here provides quantitative support for the optimal selection of initial design parameters and can be translated to designs using different form factors and fluid properties.","PeriodicalId":382522,"journal":{"name":"2018 7th IEEE International Conference on Biomedical Robotics and Biomechatronics (Biorob)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125071985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-08-01DOI: 10.1109/BIOROB.2018.8487706
Kevin Langlois, Marta Moltedo, T. Baček, C. R. Guerrero, B. Vanderborght, D. Lefeber
Exoskeletons have shown their ability to assist locomotion and augment human performances. However, the benefits of wearing these devices depend on how effectively power can be transmitted from the device to the user's biological structures. Recent studies have shown evidence of inefficient power transmission, with losses of up to 50%. The problem of power transmission can be mitigated by designing interfaces that increase contact stiffness and reduce relative motion between the limb and the robot. In this contribution, the design and development of physical interfaces for rigid lower limb exoskeletons is presented. The relative motion between the human and the developed interface is evaluated using a motion capture system and compared to the performances of a commercially available interface. Results indicate a clear reduction in relative motion between the user and the exoskeleton when the customized interface is worn.
{"title":"Design and Development of Customized Physical Interfaces to Reduce Relative Motion Between the User and a Powered Ankle Foot Exoskeleton","authors":"Kevin Langlois, Marta Moltedo, T. Baček, C. R. Guerrero, B. Vanderborght, D. Lefeber","doi":"10.1109/BIOROB.2018.8487706","DOIUrl":"https://doi.org/10.1109/BIOROB.2018.8487706","url":null,"abstract":"Exoskeletons have shown their ability to assist locomotion and augment human performances. However, the benefits of wearing these devices depend on how effectively power can be transmitted from the device to the user's biological structures. Recent studies have shown evidence of inefficient power transmission, with losses of up to 50%. The problem of power transmission can be mitigated by designing interfaces that increase contact stiffness and reduce relative motion between the limb and the robot. In this contribution, the design and development of physical interfaces for rigid lower limb exoskeletons is presented. The relative motion between the human and the developed interface is evaluated using a motion capture system and compared to the performances of a commercially available interface. Results indicate a clear reduction in relative motion between the user and the exoskeleton when the customized interface is worn.","PeriodicalId":382522,"journal":{"name":"2018 7th IEEE International Conference on Biomedical Robotics and Biomechatronics (Biorob)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132212458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-08-01DOI: 10.1109/BIOROB.2018.8487918
Quentin Sanders, Shusuke Okita, J. Lobo-Prat, D. S. D. Lucena, Brendan W. Smith, D. Reinkensmeyer
Hand exoskeletons could potentially improve hand use after stroke but are typically obtrusive and non-intuitive. Here, we provide a rationale for a control strategy suitable for a minimalistic hand exoskeleton. We also report on pilot testing of the strategy, and on a soft actuator design for implementing the strategy. The strategy is based on four experimental observations from studies conducted in our laboratory with unimpaired individuals and stroke survivors. First, using only a pinch grip, unimpaired people can achieve a substantial level of hand function when measured with clinical assessments. Second, the level of achieved function corresponds well with what is necessary to drive daily hand use, as measured by a novel wearable sensor with stroke survivors. Third, even people with severe hand impairment after stroke have a well-preserved ability to control isometric finger flexion force, even though they cannot use their hand to manipulate objects. Fourth, such individuals also exhibit highly correlated forces between fingers. From these observations we propose a control strategy that measures residual finger flexion of digits 3–5 (middle-pinky fingers) to control the force of an exoskeleton assisting in pinch grip. We implemented this “residual force control” strategy using the FINGER exoskeleton and found that unimpaired subjects could intuitively use this strategy to pick up an object and learn to amplify their grip force (Repeated Measures ANOVA, $mathbf{p} pmb{< 004}$). We have also begun developing a soft exoskeleton to implement the residual force control strategy, and we report on the actuator design here. The results of preliminary testing of the actuator show that the actuator could produce a sufficient amount of force ($pmb{13.06} mathbf{N}pmb{pm.33} mathbf{SD})$ to assist the hand.
{"title":"Design and Control of a Novel Grip Amplifier to Support Pinch Grip with a Minimal Soft Hand Exoskeleton","authors":"Quentin Sanders, Shusuke Okita, J. Lobo-Prat, D. S. D. Lucena, Brendan W. Smith, D. Reinkensmeyer","doi":"10.1109/BIOROB.2018.8487918","DOIUrl":"https://doi.org/10.1109/BIOROB.2018.8487918","url":null,"abstract":"Hand exoskeletons could potentially improve hand use after stroke but are typically obtrusive and non-intuitive. Here, we provide a rationale for a control strategy suitable for a minimalistic hand exoskeleton. We also report on pilot testing of the strategy, and on a soft actuator design for implementing the strategy. The strategy is based on four experimental observations from studies conducted in our laboratory with unimpaired individuals and stroke survivors. First, using only a pinch grip, unimpaired people can achieve a substantial level of hand function when measured with clinical assessments. Second, the level of achieved function corresponds well with what is necessary to drive daily hand use, as measured by a novel wearable sensor with stroke survivors. Third, even people with severe hand impairment after stroke have a well-preserved ability to control isometric finger flexion force, even though they cannot use their hand to manipulate objects. Fourth, such individuals also exhibit highly correlated forces between fingers. From these observations we propose a control strategy that measures residual finger flexion of digits 3–5 (middle-pinky fingers) to control the force of an exoskeleton assisting in pinch grip. We implemented this “residual force control” strategy using the FINGER exoskeleton and found that unimpaired subjects could intuitively use this strategy to pick up an object and learn to amplify their grip force (Repeated Measures ANOVA, $mathbf{p} pmb{< 004}$). We have also begun developing a soft exoskeleton to implement the residual force control strategy, and we report on the actuator design here. The results of preliminary testing of the actuator show that the actuator could produce a sufficient amount of force ($pmb{13.06} mathbf{N}pmb{pm.33} mathbf{SD})$ to assist the hand.","PeriodicalId":382522,"journal":{"name":"2018 7th IEEE International Conference on Biomedical Robotics and Biomechatronics (Biorob)","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133489553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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