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Various exoskeleton robots are being developed according to users’ conditions. Lower limb exoskeleton robots have attracted much attention for performing walking motions, a basic exercise for paralyzed patients. In this study, the walking environment of an exoskeleton robot wearer who walks using a crutch is identified as the foot position of the c...
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... self-balancing and walking [10], employing active disturbance rejection control for gait tracking in rehabilitation [11], designing EMG-based admittance controller for stable human-robot interaction [12], and creating adjustable gait patterns through a kinematic parameter identification [13]. Innovative methods also were proposed to assist spinal cord injury patients in movement restoration using basis function interpolation [14] and to assist with stairs and ramps [15]. ...
... However, given hardware complexities, the reduced speed of 0.46 m/s with a cycle time of 2 s is considered for the coupled subject-exoskeleton system during the control experiments. It is imperative to mention that several researchers, as per hardware requirements, have conducted their coupled subject-exoskeleton experiment with different gait cycles, such as 1 s [51] and 2 s [52,53] for motion assistance and gait rehabilitation. Experiments involving human subjects and exoskeletons were conducted with approval from the Institute's Human Ethics Committee, granted on February 28, 2020. ...
Existing exoskeletons for pediatric gait assistance have limitations in anthropometric design, structure weight, cost, user safety features, and adaptability to diverse users. Additionally, creating precise models for pediatric rehabilitation is difficult because the rapid anthropometric changes in children result in unknown model parameters. Furthermore, external disruptions, like unpredictable movements and involuntary muscle contractions, add complexity to the control schemes that need to be managed. To overcome these limitations, this study aims to develop an affordable stand-aided lower-limb exoskeleton specifically for pediatric subjects (8-12 years, 25-40 kg, 128-132 cm) in passive-assist mode. The authors modified a previously developed model (LLESv1) for improved rigidity, reduced mass, simplified motor arrangement, variable waist size, and enhanced mobility. A computer-aided design of the new exoskeleton system (LLESv2) is presented. The developed prototype of the exoskeleton appended with a pediatric subject (age: 12 years old, body mass: 40 kg, body height: 132 cm) is presented with real-time hardware architecture. Thereafter, an improved fast non-singular terminal sliding mode (IFNSTSM) control scheme is proposed, incorporating a double exponential reaching law for expedited error convergence and enhanced stability. The Lyapunov stability warrants the control system's performance despite uncertainties and disturbances. In contrast to fast non-singular terminal sliding mode (FNSTSM) control and time-scaling sliding mode (TSSM) control, experimental validation demonstrates the effectiveness of IFNSTSM control by a respective average of 5.39% and 42.1% in tracking desired joint trajectories with minimal and rapid finite time converging errors. Moreover, the exoskeleton with the proposed IFNSTSM control requires significantly lesser control efforts than the exoskeleton using contrast FNSTSM control. The Bland-Altman analysis indicates that although there is a minimal mean difference in variables when employing FNSTSM and IFNSTSM controllers, the latter exhibits significant performance variations as the mean of variables changes. This research contributes to affordable and effective pediatric gait assistance, improving rehabilitation outcomes and enhancing mobility support.
... The walking cadence of a gait with different step lengths was maximized using the particle swarm optimization problem in [27]. The DMP-based approach was employed to model the joint trajectories with reinforcement learning, and locally weighted regression learning in [28] and [29], respectively, but it could not consider angular velocity. The swing leg was modeled as a double pendulum to generate the trajectory with minimum torques of joints by introducing the cost function and solving an optimization problem [30]. ...
Assistive lower limb exoskeleton robot has been developed to help paraplegic patients walk again. A gait planning method of this robot must be able to plan a gait based on gait parameters, which can be changed during the stride according to human intention or walking conditions. The gait is usually planned in cartesian space, which has shortcomings such as singularities that may occur in inverse kinematics equations, and the angular velocity of the joints cannot be entered into the calculations. Therefore, it is vital to have a gait planning method in the joint space. In this paper, a minimum-time and minimum-jerk planner is proposed for the robot joints. To do so, a third-order system is defined, and the cost function is introduced to minimize the jerk of the joints throughout the stride. The minimum time required is calculated to keep the angular velocity trajectory within the range specified by the motor’s maximum speed. Boundary conditions of the joints are determined to secure backward balance and fulfill gait parameters. Finally, the proposed gait planning method is tested by its implementation on the Exoped® exoskeleton.
... On the basis of a single degree of freedom robot, lower limb rehabilitation robots with more than one degree of freedom have been developed rapidly in the past few decades, including wearable exoskeleton robots [11] and suspended rehabilitation robots. For example, Rewalk [12,13], composed of a pair of hip motors, a pair of knee joint motors, and a backpack integrating the control system and rechargeable batteries, can imitate the normal gait of the human body based on the preset movement model with an appropriate speed. Other typical wearable exoskeleton robots include Indego [14], Machines 2022, 10, 674 2 of 16 HAL [15], Exo-H2 [16], and ROBIN [17]. ...
To meet the various need of stroke patients’ rehabilitation training and carry out complex task training in real scenes, the structure of a lower limb rehabilitation robot with movements in the sagittal plane and coronal plane is usually complicated. A new sitting/lying lower limb rehabilitation robot (LOBO) with a simple mechanism form is proposed, which is designed based on a 2-PRR parallel mechanism. First, the kinematics, singularity, and condition number of the 2-PRR parallel mechanism are analyzed, which provides the basis for mechanism parameter design. Then, through the proportional–derivative control principle, real-time tracking of LOBO’s designed trajectory is realized. Finally, the length parameters of volunteers’ lower limbs are collected, and experimental verification is conducted in LOBO’s passive training mode. The experimental results show the feasibility of LOBO’s movement in the human sagittal and coronal planes. LOBO will help human lower limbs realize the synchronous continuous rehabilitation training of hip, knee, and ankle joints spatially, which could drive the rehabilitation movement of patients’ lower limbs in the sagittal plane and coronal plane in future clinical research. LOBO can also be applied to muscle strength training for the elderly to combat the effects of aging.
... Robotic exoskeletons can be mainly divided into the medical type and nonmedical type according to their applications. Medical type exoskeleton is used for patients with upper (Yan and Yang, 2014;Gandolla et al., 2021) or lower body disabilities (Yang et al., 2016;Hwang et al., 2021;Zhu et al., 2021). With this kind of exoskeleton, some patients can regain the ability of locomotion (Farris et al., 2014), while some other patients can achieve therapeutic movement and speed up rehabilitation progress Yang et al., 2020). ...
The aging population is now a global challenge, and impaired walking ability is a common feature in the elderly. In addition, some occupations such as military and relief workers require extra physical help to perform tasks efficiently. Robotic hip exoskeletons can support ambulatory functions in the elderly and augment human performance in healthy people during normal walking and loaded walking by providing assistive torque. In this review, the current development of robotic hip exoskeletons is presented. In addition, the framework of actuation joints and the high-level control strategy (including the sensors and data collection, the way to recognize gait phase, the algorithms to generate the assist torque) are described. The exoskeleton prototypes proposed by researchers in recent years are organized to benefit the related fields realizing the limitations of the available robotic hip exoskeletons, therefore, this work tends to be an influential factor with a better understanding of the development and state-of-the-art technology.
... To provide the dominant motion in the sagittal plane (e.g., flexion/extension), the exoskeleton robot Walking Assist for Hemiplegia patients (WA-H) was integrated. It was developed in our previous work and evaluated for assistive motion in hip/knee flexion/ extension [21,22]. The pelvic obliquity support mechanism is developed to generate the pelvic obliquity motion in the patient's frontal plane with two independently op-erated scissor mechanisms on each side of the patient. ...
... Each active joint has a passive mode in which the wearer can move freely by assisting only gravity compensation and harmonic drive friction compensation torque, and an active mode in which the robot assists force to the user by using the training gait pattern. In addition, the robot can possibly generate gait patterns by measuring the user pose and generating a walking pattern corresponding to the user pose [21]. We even verified the effect of the gait rehabilitation by using our robot with hemiplegia patients through previous studies [22]. ...
In this work, we present the overground prototype gait-rehabilitation robot for using motion assistance and training for paralyzed patients. In contrast to the existing gait-rehabilitation robots, which focus on the sagittal plane motion of the hip and knee, we aim to develop a mobile-based pelvic support gait-rehabilitation system that includes a pelvic obliquity support mechanism and a lower-limb exoskeleton. To achieve this, a scissor mechanism is proposed to generate the paralyzed patient's pelvic obliquity motion and weight support. Moreover, the lower limb exoskeleton robot is integrated with the developed system to provide the patient's gait by correcting mechanical aids. We used computer-aided analysis to verify the performance of the prototype hardware itself. Through these methods, it was shown that our motor can sufficiently lift 100 kg of user weight through the scissor mechanism, and that the mobile driving wheel motor can operate at a speed of 1.6 m/s of human walking, showing that it can be used for gait rehabilitation of patients in need of a lower speed. In addition, we verified that the system drives the model by generating pelvic motion, and we verified the position controller of the integrated system, which supports the multi-degree motion by creating hip/knee/pelvic motion with a human dummy mannequin and systems. We believe that the proposed system can help address the complex rehabilitation motion assistance and training of paralyzed patients.
... In addition, it is convenient for maintenance personnel to carry out overhaul and maintenance of related problems in time. Compared with the algorithm proposed by Hwang et al. (2021) [31], the advantage of its research is that the walking environment of the exoskeleton robot wearer using crutches is determined as the crutches support point and the foot position of the supporting leg. Different from using preset pedestrian patterns, it uses dynamic motion primitive machine learning technology to create pedestrian patterns that can match the environment. ...
... In addition, it is convenient for maintenance personnel to carry out overhaul and maintenance of related problems in time. Compared with the algorithm proposed by Hwang et al. (2021) [31], the advantage of its research is that the walking environment of the exoskeleton robot wearer using crutches is determined as the crutches support point and the foot position of the supporting leg. Different from using preset pedestrian patterns, it uses dynamic motion primitive machine learning technology to create pedestrian patterns that can match the environment. ...
The Internet of Things (IoT) technology and robotics technology are applied to the smart medicine to reduce the labor intensity of medical staff and complete more work within unit time. A narrowband intelligent medical system based on the IoT is designed by taking the lower limb exoskeleton robot rehabilitation system as the entry point. In this study, the key points of the IoT technology are analyzed firstly, and the model of the robot rehabilitation system and the overall system architecture are designed. Then, the software and hardware of the patient data acquisition equipment are designed, realizing interaction between the information acquisition platform and other functions. Thirdly, the system management software is designed, and the medical information communication and management is constructed between the user and the intelligent cloud platform and the hospital server. Finally, a smart rehabilitation system is built to realize quick response to user needs. The test results show that the system constructed in this study can realize the real-time, automatic, and remote upload of the collected information of patients, so that the information is not restricted by the location and it is convenient for doctors to diagnose the condition of patient anytime and anywhere. The system designed in this study provides a reference for the application of advanced IoT technology in medical diagnosis.
... The LEE wearer can move around safely and flexibly for a long time at high speed under heavy load. The LEE has been widely used in marching, weight-bearing combat, and medical rehabilitation proposes [12,13]. ...
In the current study, our research group proposed an asymmetric lower extremity exoskeleton to enable above-knee amputees to walk with a load. Due to the absence of shank and foot, the knee and ankle joint at the amputation side of the exoskeleton lack tracking targets, so it is difficult to realize the function of assisted walking when going up and downstairs. Currently, the use of lower-limb electromyography to predict the angles of lower limb joints has achieved remarkable results. However, the prediction effect was poor when only using electromyography from the thigh. Therefore, this paper introduces hip-angle and plantar pressure signals for improving prediction effect and puts forward a joint prediction method of knee- and ankle-joint angles by electromyography of the thigh, hip-joint angle, and plantar pressure signals. The generalized regression neural network optimized by the golden section method is used to predict the joint angles. Finally, the parameters (the maximum error, the Root-Mean-Square error (RMSE), and correlation coefficient (γ)) were calculated to verify the feasibility of the prediction method.
Biological systems, including human beings, have the innate ability to perform complex tasks in a versatile and agile manner. Researchers in sensorimotor control have aimed to comprehend and formally define this innate characteristic. The idea, supported by several experimental findings, that biological systems are able to combine and adapt basic units of motion into complex tasks finally leads to the formulation of the motor primitives’ theory. In this respect, Dynamic Movement Primitives (DMPs) represent an elegant mathematical formulation of the motor primitives as stable dynamical systems and are well suited to generate motor commands for artificial systems like robots. In the last decades, DMPs have inspired researchers in different robotic fields including imitation and reinforcement learning, optimal control, physical interaction, and human–robot co-working, resulting in a considerable amount of published papers. The goal of this tutorial survey is two-fold. On one side, we present the existing DMP formulations in rigorous mathematical terms and discuss the advantages and limitations of each approach as well as practical implementation details. In the tutorial vein, we also search for existing implementations of presented approaches and release several others. On the other side, we provide a systematic and comprehensive review of existing literature and categorize state-of-the-art work on DMP. The paper concludes with a discussion on the limitations of DMPs and an outline of possible research directions.
