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Author: Visharath Adhikari
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 83
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Book Description
This thesis aims to design a novel task based knee rehabilitation exoskeleton device through kinematic synthesis. In contrast to prevailing research efforts, which attempt to mimic the human limb by assigning each human joint with an equivalent exoskeleton joint (e.g. a hinge joint for the elbow and knee), this thesis provides an alternative systematic approach for the design of exoskeletons to assist the complex 3D motions of the human Knee. With this method, it is not necessary to know the anatomy of the targeted limb, but rather to define the motion of the exoskeleton segments based on its point of attachment to the limb. Good alignment is often difficult and the distances between joints must be adjusted to accommodate the variety of human size. Furthermore, attempting to align each robotic joint axis with its human counterpart assumes that the position of the axis can be accurately known, and that such a fixed axis exists for the range of motion of the joint or set of joints, which is not always the case. In human- exoskeletons synergy, especially in industrial settings and rehabilitation applications, due to the repetitive and strenuous nature of the task, the fit, comfort and usability of these exoskeletons are important for the safety of the user and for the automation of the task. Improper fitting may lead an exoskeleton to move in a way that exceeds the range of movement of the human body and tear muscle ligaments or dislocate joints. In this thesis, to study the motion of the desired clinical trajectories of the human knee, the state-of-the-art of motion capture and data analysis techniques are utilized. The collected experimental kinematic data is used as an input to the kinematic synthesis. Parallel mechanisms with single degree-of-freedom (DOF) are considered to generate the complex 3D motions of the lower leg. An exact workspace synthesis approach is utilized, in which, the parameterized forward kinematics equations of each serial chain are to be converted to implicit equations via elimination. The implicit description of the workspace is made to be a function of the structural parameters of the serial chain, making it easy to relate those parameters to the motion capture data. A prototype of the mechanism has been built using 3D printing technology. And an Electromyography (EMG) signals and Force sensing resistors (FSR) are utilized to implement an assist as needed controller. The EMG signal is captured from the user leg and force sensing resistors (FSR) are applied at the attachment point of the exoskeleton and the leg, this helps to get the amount of force applied by the exoskeleton to the leg as well as for recovery tracking. The assist as needed controller eliminates the need of constant supervision, and hence saves time and reduces cost of the rehabilitation process.
Author: Visharath Adhikari
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 83
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Book Description
This thesis aims to design a novel task based knee rehabilitation exoskeleton device through kinematic synthesis. In contrast to prevailing research efforts, which attempt to mimic the human limb by assigning each human joint with an equivalent exoskeleton joint (e.g. a hinge joint for the elbow and knee), this thesis provides an alternative systematic approach for the design of exoskeletons to assist the complex 3D motions of the human Knee. With this method, it is not necessary to know the anatomy of the targeted limb, but rather to define the motion of the exoskeleton segments based on its point of attachment to the limb. Good alignment is often difficult and the distances between joints must be adjusted to accommodate the variety of human size. Furthermore, attempting to align each robotic joint axis with its human counterpart assumes that the position of the axis can be accurately known, and that such a fixed axis exists for the range of motion of the joint or set of joints, which is not always the case. In human- exoskeletons synergy, especially in industrial settings and rehabilitation applications, due to the repetitive and strenuous nature of the task, the fit, comfort and usability of these exoskeletons are important for the safety of the user and for the automation of the task. Improper fitting may lead an exoskeleton to move in a way that exceeds the range of movement of the human body and tear muscle ligaments or dislocate joints. In this thesis, to study the motion of the desired clinical trajectories of the human knee, the state-of-the-art of motion capture and data analysis techniques are utilized. The collected experimental kinematic data is used as an input to the kinematic synthesis. Parallel mechanisms with single degree-of-freedom (DOF) are considered to generate the complex 3D motions of the lower leg. An exact workspace synthesis approach is utilized, in which, the parameterized forward kinematics equations of each serial chain are to be converted to implicit equations via elimination. The implicit description of the workspace is made to be a function of the structural parameters of the serial chain, making it easy to relate those parameters to the motion capture data. A prototype of the mechanism has been built using 3D printing technology. And an Electromyography (EMG) signals and Force sensing resistors (FSR) are utilized to implement an assist as needed controller. The EMG signal is captured from the user leg and force sensing resistors (FSR) are applied at the attachment point of the exoskeleton and the leg, this helps to get the amount of force applied by the exoskeleton to the leg as well as for recovery tracking. The assist as needed controller eliminates the need of constant supervision, and hence saves time and reduces cost of the rehabilitation process.
Author: Shahid Hussain
Publisher:
ISBN:
Category : Gait disorders
Languages : en
Pages : 176
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Book Description
Neurologic injuries, such as stroke and spinal cord injuries (SCI), cause damage to neural systems and motor function, which results in lower limb impairment and gait disorders. Subjects with gait disorders require specific training to regain functional mobility. Traditionally, manual physical therapy is used for the gait training of neurologically impaired subjects which has limitations, such as the excessive workload and fatigue of physical therapists. The rehabilitation engineering community is working towards the development of robotic devices and control schemes that can assist during the gait training. The initial prototypes of these robotic gait training orthoses use conventional, industrial actuators that are either extremely heavy or have high endpoint impedance (stiffness). Neurologically impaired subjects often suffer from severe spasms. These stiff actuators may produce forces in response to the undesirable motions, often causing pain or discomfort to patients. The control schemes used by the initial prototypes of robotic gait training orthoses also have a limited ability to provide seamless, adaptive, and customized robotic assistance. This requires new design and control methods to be developed to increase the compliance and adaptability of these automated gait training devices. This research introduces the development of a new robotic gait training orthosis that is intrinsically compliant. Novel, assist-as-needed (AAN) control strategies are proposed to provide adaptive and customized robotic assistance to subjects with different levels of neurologic impairments. The new robotic gait training orthosis has six degrees of freedom (DOFs), which is powered by pneumatic muscle actuators (PMA). The device provides naturalistic gait pattern and safe interaction with subjects during gait training. New robust feedback control schemes are proposed to improve the trajectory tracking performance of PMAs. A dynamic model of the device and a human lower limb musculoskeletal model are established to study the dynamic interaction between the device and subjects. In order to provide adaptive, customized robot assisted gait training and to enhance the subject's voluntary participation in the gait training process, two new control schemes are proposed in this research. The first control scheme is based on the impedance control law. The impedance control law modifies the robotic assistance based on the human subject's active joint torque contributions. The levels of robot compliance can be selected by the physical therapist during the impedance control scheme according to the disability level and stage of rehabilitation of neurologically impaired subjects. The second control scheme is proposed to overcome the shortcomings of impedance control scheme and to provide seamless adaptive, AAN gait training. The adaptive, AAN gait training scheme is based on the estimation of the disability level of neurologically impaired subjects based on the kinematic error and adapts the robotic assistance accordingly. All the control schemes have been evaluated on neurologically intact subjects and the results show that these control schemes can deliver their intended effects. Rigorous clinical trials with neurologically impaired subjects are required to prove the therapeutic efficacy of the proposed robotic orthosis and the adaptive gait training schemes. The concept of intrinsically compliant robotic gait training orthosis, together with the trajectory tracking and impedance control of robotic gait training orthosis are the important contributions of this research. The algorithms and models developed in this research are applicable to the development of other robotic devices for rehabilitation and assistive purposes. The major contribution of the research lies in the development of a seamless, adaptive AAN gait training strategy. The research will help in evolving the field of compliant actuation of rehabilitation robots along with the development of new control schemes for providing seamless, adaptive AAN gait training.
Author: Manuel Cardona
Publisher: Springer Nature
ISBN: 9811547327
Category : Science
Languages : en
Pages : 103
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Book Description
This book addresses cutting-edge topics in robotics and related technologies for rehabilitation, covering basic concepts and providing the reader with the information they need to solve various practical problems. Intended as a reference guide to the application of robotics in rehabilitation, it covers e.g. musculoskeletal modelling, gait analysis, biomechanics, robotics modelling and simulation, sensors, wearable devices, and the Internet of Medical Things.
Author: Priyanshu Agarwal
Publisher:
ISBN:
Category :
Languages : en
Pages : 462
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Book Description
Rehabilitation of the hands is critical for restoring independence in activities of daily living for individuals with upper extremity disabilities. Conventional therapies for hand rehabilitation have not shown significant improvement in hand function. Robotic exoskeletons have been developed to assist in therapy and there is initial evidence that such devices with force-control based strategies can help in effective rehabilitation of human limbs. However, to the best of our knowledge, none of the existing hand exoskeletons allow for accurate force or torque control. In this dissertation, we design and prototype a novel hand exoskeleton that has the following unique features: (i) Bowden-cable-based series elastic actuation allowing for bidirectional torque control of each joint individually, (ii) an underlying kinematic mechanism that is optimized to achieve large range of motion and (iii) a thumb module that allows for independent actuation of the four thumb joints. To control the developed hand exoskeleton for efficacious rehabilitation after a neuromuscular impairment such as stroke, we present two types of subject-specific assist-as-needed controllers. Learned force-field control is a novel control technique in which a neural-network-based model of the required torques given the joint angles for a specific subject is learned and then used to build a force-field to assist the joint motion of the subject to follow a trajectory designed in the joint-angle space. Adaptive assist-as-needed control, on the other hand, estimates the coupled digit-exoskeleton system torque requirement of a subject using radial basis function (RBF) and on-the-y adapts the RBF magnitudes to provide a feed-forward assistance for improved trajectory tracking. Experiments with healthy human subjects showed that each controller has its own trade-offs and is suitable for a specific type of impairment. Finally, to promote and optimize motor (re)-learning, we present a framework for robot-assisted motor (re)-learning that provides subject-specific training by allowing for simultaneous adaptation of task, assistance and feedback based on the performance of the subject on the task. To train the subjects for dexterous manipulation, we present a torque-based task that requires subjects to dynamically regulate their joint torques. A pilot study carried out with healthy human subjects using the developed hand exoskeleton suggests that training under simultaneous adaptation of task, assistance and feedback can module challenge and affect their motor learning.
Author: Robert Trott
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Stroke is the second highest cause of death worldwide and the third leading cause of adult disability across all age brackets. Recovering gait following stroke is a major goal of patients, and hence rehabilitation, as it is central to many activities of daily living. Of the different treatment modalities, robotic assisted gait training is growing in popularity, but is still considered complementary to, and not substitute for conventional therapies comprising physiotherapy, overground walking and body weight supported treadmill training. The potential advantages that lower limb robotics bring to neurorehabilitation over conventional therapies include, higher dosage, specificity, improved consistency, and duration, though these benefits have been slow to manifest. Exoskeletons are well placed to provide these benefits, as well as environmental variation and task salience if they can be used away from outpatient settings. Control strategies that may be enhancing of recovery are often confined to stationary exoskeletons, and the control of mobile exoskeletons is only loosely related to gait, if at all, which limits rehabilitation outcomes. -- The primary aim of this PhD thesis was to develop an adaptive, user-initiated gait Controller that aims to target a novel neural recovery pathway. The Controller would use a robotic exoskeleton, with the intention of developing novel neuroplasticity that is beneficial for gait and would be permissive of simultaneous control of hip and knee posture. A theoretical framework based on the principles of neuroplasticity was proposed that seeks to bring higher engagement, task variance, and volition to gait rehabilitation. This framework considers stroke and rehabilitation timelines and the interaction of the proposal with existing theory, how beneficial neuroplasticity may manifest, and how the proposal may be detrimental. A comprehensive survey of candidate lower limb devices followed (164 devices), to understand exactly what features are compatible, complementary, or contradictory to the proposed control method, and to understand the implications the various specifications have. Specifically, it was found that ambulating exoskeletons that can move around the environment were preferred for their ability to be used in the community and the home, and that extended joint range of motion will be permissive of activities that are supportive of gait such as sit-to-stand and stair ascent/descent. Of the various control systems that have been implemented with exoskeleton devices, trajectory control, where motion is enforced on the limb by the exoskeleton, is preferred. -- The method of control was assessed for suitability as a gait controller through a participant study (n = 21). Participants were asked to reproduce the motion required for the controller, and with minor modification to participant motion it was shown that reliable control signals can be obtained. The remainder of the thesis applies the learnings of the previous stages in the development of the Controller and an accompanying Sensor. The custom Sensor was designed with a small form factor to be applied on the Controller. The thesis concludes with an implementation of the Controller and a successful demonstration of the proposed concept, where the control signals are reproduced on a scale lower limb exoskeleton. The full technical detail and specification of the Controller, and the custom position Sensor developed specific for this application, are presented as part of this work. -- This work has added a new theoretical framework for gait control following stroke and has added technological capability to implement the proposal. It is the primary recommendation of this PhD that the novel control method be tested further with participant studies and that the component hardware be developed further. Therapies targeting novel recovery mechanisms breathe fresh air into rehabilitation and may inspire other new treatments, and future funded work originating from this PhD will see the concept tested with a chronic stroke population, using an ambulating exoskeleton and the Controller.
Author: Nicola Secciani
Publisher: Springer Nature
ISBN: 3030902838
Category : Technology & Engineering
Languages : en
Pages : 103
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Book Description
This book reports on the design and testing of an sEMG-based control strategy for a fully-wearable low-cost hand exoskeleton. It describes in detail the modifications carried out to the electronics of a previous prototype, covering in turn the implementation of an innovative sEMG classifier for predicting the wearer's motor intention and driving the exoskeleton accordingly. While similar classifier have been widely used for motor intention prediction, their application to wearable device control has been neglected so far. Thus, this book fills a gap in the literature providing readers with extensive information and a source of inspiration for the future design and control of medical and assistive devices.
Author: Francisco Romero Sánchez
Publisher: Frontiers Media SA
ISBN: 2889768813
Category : Science
Languages : en
Pages : 229
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Author: Julio Salvador Lora Millán
Publisher: Springer Nature
ISBN: 3031576160
Category :
Languages : en
Pages : 154
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Book Description
Author: Jinghui Brian Cao
Publisher:
ISBN:
Category : Gait disorders
Languages : en
Pages : 177
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Book Description
Gait disorder is a commonly lasting side-effect for stroke and spinal cord injury survivors. Conventional gait rehabilitation trainings provided by therapists are largely dependent on their experience. Such trainings are often challenging for the therapists due to their physically intensive nature. Hence, consistent optimal results cannot always be achieved. Robotic technologies were thus introduced to automate the gait rehabilitation trainings, in order to emancipate therapists from physically intensive work as well as making rehabilitation training more accessible to patients Research have shown that task specific repetitive training and patients' active participation can lead to more effective gait rehabilitation. However, conventional trajectory tracking controlled robotic gait rehabilitation could change the dynamics of the walking task, reduce inputs from patients' motor systems, lower their physical effort and thus result less effective outcomes. Therefore, it is important to ensure that the robotic gait rehabilitation training is more analogous to actual human walking and maximize the training subject's active participation. The goal of this thesis is the development of a new robotic GAit Rehabilitation EXoskeleton (GAREX) that is compliant with the current neurorehabilitation theories in order to achieve optimised robotic gait rehabilitation. Such goal is tackled systematically in terms of both robotic design and control algorithm research. GAREX was designed to provide safe, task specific gait rehabilitation to stroke patients. Pneumatic muscles (PM) actuators were used to drive GAREX, due to their high power/force to weight ratio and intrinsic compliance. Specially, the intrinsic compliance can create a wide range of dynamic environment for control strategy development. However, the negative correlation between PM's force output and contracting length means a trade-off between torque and range of motion specifications of the actuation system. The design of GAREX comprehensively addressed torque and joint range of motion requirements imposed by task-specific gait rehabilitation training. Control strategies are the key to implement the training theories into robotic operations. In order to encourage patients' active participation, the robot should be controlled to supply just enough guidance/assistance a patient needs to complete treadmill based gait training. To implement assist-as-needed (AAN) concept, the robot should also be able to assess the extent of active participation and change the assistance provided accordingly. The intrinsic compliance of GAREX's PM actuation system could be utilized to change the level of guidance. A new multi-input-multi-output (MIMO) sliding model (SM) controller was developed to adjust assistance while guiding training subjects to walk in predefined gait trajectories. Technical experimental validation indicated that controller was able to track reference gait trajectories and the desired joint space average antagonistic PM pressures. A study with 12 healthy subjects revealed strong statistical evidence that the proposed MIMO SM controller is able to vary the compliance of the exoskeleton To online assess the training patient's active participation, a fuzzy logic compliance adaptation (FLCA) controller is proposed. The FLCA algorithm utilizes the robotic kinematics and human- exoskeleton interaction torque of the knee joint, to estimate the extent of the patient's active participation. Based on the estimation, the desired compliance level can be automatically adjusted with higher compliance for more active participation and vice versa. Nevertheless, the FLCA algorithm does not require models of the exoskeleton and biomechanics of the training subject, which means less preparation work and easier implementation. Performance of the FLCA control system was validated with three healthy subjects who simulated different extents of participation. The FLCA control system could successfully adapt the joint actuation compliance accordingly in all the scenarios.
Author: Akim Kapsalyamov
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Repetitive and task-oriented movements can strengthen muscles and improve walking capabilities among patients experiencing gait impairments due to neurological disorders. The demand for effective rehabilitation is high, given the large number of patients suffering from gait impairments. The traditional physiotherapy is laborious, may not provide the desired cadence and gait patterns, and requires constant presence of physiotherapists. This often leads to delayed treatment for many patients due to the high demand and a shortage of physiotherapists. Early phase post-stroke gait rehabilitation is crucial, as the ability to recuperate lost muscular abilities reduces over time. Lower limb wearable rehabilitation robots have shown promise in improving the locomotor capabilities of patients experiencing gait impairments and reducing the burden on physiotherapists. However, the high cost of commercially available robots makes this technology inaccessible to many hospitals and rehabilitation centers. To address this issue, ongoing research is focusing on improving existing rehabilitation robots in terms of ease of use, innovative design, and cost reduction. Closed-loop linkage mechanisms have recently drawn attention in the development of gait rehabilitation robots due to their ability to address the drawbacks of commercially available robot orthoses. These mechanisms are affordable and capable of providing suitable trajectories for gait training therapy. One of the challenging aspects in designing linkage-based robots is determining and calculating linkage parameters that will produce the required gait trajectories. This thesis presents an innovative approach to synthesizing the linkage dimensions to provide natural gait trajectories. Additionally, it introduces a novel and affordable robotic orthosis based on Stephenson III's six-bar linkage. The developed gait rehabilitation orthosis is a bilateral system powered by a single actuator on each side of the leg, capable of providing naturalistic knee and ankle joint motions relative to the hip joint, which are required during therapeutic gait training. This orthosis can be used in clinical settings and is actuated using only a single motor, yet it is capable of providing complex lower limb trajectory motions at its end-effector. The initial design optimization was carried out using a genetic algorithm (GA), and a deep generative neural network model was developed for the linkage synthesis problem. This model represents an advancement in current kinematic synthesis methods, enabling it to generate dimensions of the links that satisfy various required target human lower limb trajectories during walking in a short period. It will assist designers in determining optimal linkage dimensions to generate the required end-effector trajectories within a single mechanism. To enhance the mechanism's velocity regulation control scheme and address fluctuations that may occur during operation due to external disturbances such as fixed patient's leg and inertia in closed loop linkage mechanisms, a Deep Reinforcement Learning control scheme was proposed to regulate the speed of the input crank to reach satisfactory performance needed for gait rehabilitation training. Experimental evaluations with healthy human subjects were conducted to demonstrate that the mechanism is capable of directing lower limbs on naturalistic gait trajectories with a required walking speed. Furthermore, given the varied disability levels among neurologically impaired patients, the orthosis incorporates a patient cooperative control strategy. This is achieved through the application of impedance learning control, operating on an "assist-as-needed" principle. This innovative approach enables the robot to modify the assistive force it provides during gait cycle aligning with the patient's disability level and contributing towards active participation during the gait rehabilitation training. The proposed control scheme was evaluated in two distinct gait training modes while being worn by a human subject. In the "passive" mode subjects refrained from moving their legs, allowing the robot to guide their movements. While during the second 'active' mode, the subject engaged in normal walking activity while wearing the robot. Experimental results with healthy human subjects indicated reduced robot torques consequent to an increase in human torque. These results substantiate that customized robotic assistance based on the individual needs of patients can enhance their participation, which is essential to improve the treatment outcomes. The concept of this research lies in the development of a novel, affordable, and adaptable robotic orthosis based on Stephenson III's six-bar linkage mechanism, capable of delivering naturalistic individualized lower limb motion. It advances the fields of dimensional synthesis of closed loop linkage mechanisms rehabilitation robotics with the use of deep generative neural network and a Deep Reinforcement Learning control scheme for enhanced velocity regulation. Moreover, the application of impedance learning control encourages active patient participation in gait rehabilitation training by customizing assistive force based on the patient's disability level. With these advancements, the research contributes significantly to the development of more cost-effective, adaptable, and efficient robotic gait rehabilitation systems, presenting a promising solution for improving therapeutic outcomes for patients with gait impairments due to neurological disorders.
