Wearable Robots for Human Underwater Movement Ability Enhancement:A Survey

Underwater robot technology has shown impressive results in applications such as underwater resource detection.For underwater applications that require extremely high flexibility,robots cannot replace skills that require human dexterity yet,and thus humans are often required to directly perform most underwater operations.Wearable robots(exoskeletons)have shown outstanding results in enhancing human movement on land.They are expected to have great potential to enhance human underwater movement.The purpose of this survey is to analyze the state-of-the-art of underwater exoskeletons for human enhancement,and the applications focused on movement assistance while excluding underwater robotic devices that help to keep the temperature and pressure in the range that people can withstand.This work discusses the challenges of existing exoskeletons for human underwater movement assistance,which mainly includes human underwater motion intention perception,underwater exoskeleton modeling and human-cooperative control.Future research should focus on developing novel wearable robotic structures for underwater motion assistance,exploiting advanced sensors and fusion algorithms for human underwater motion intention perception,building up a dynamic model of underwater exoskeletons and exploring human-in-theloop control for them.

Cross-industry standard test method developments：from manufacturing to wearable robots

Manufacturing robotics is moving towards human-robot collaboration with light duty robots being used side by side with workers. Similarly, exoskeletons that are both passive(spring and counterbalance forces) and active(motor forces) are worn by humans and used to move body parts. Exoskeletons are also called ‘wearable robots' when they are actively controlled using a computer and integrated sensing. Safety standards now allow, through risk assessment, both manufacturing and wearable robots to be used. However, performance standards for both systems are still lacking. Ongoing research to develop standard test methods to assess the performance of manufacturing robots and emergency response robots can inspire similar test methods for exoskeletons. This paper describes recent research on performance standards for manufacturing robots as well as search and rescue robots. It also discusses how the performance of wearable robots could benefit from using the same test methods.

Development of a Wearable Upper Limb Rehabilitation Robot Based on Reinforced Soft Pneumatic Actuators

Dyskinesia of the upper limbs caused by stroke,sports injury,or trafc accidents limits the ability to perform the activities of daily living.Besides the necessary medical treatment,correct and scientifc rehabilitation training for the injured joint is an important auxiliary means during the treatment of the efected upper limb.Conventional upperlimb rehabilitation robots have some disadvantages,such as a complex structure,poor compliance,high cost,and poor portability.In this study,a novel soft wearable upper limb rehabilitation robot(SWULRR)with reinforced soft pneumatic actuators(RSPAs)that can withstand high pressure and featuring excellent loading characteristics was developed.Driven by RSPAs,this portable SWULRR can perform rehabilitation training of the wrist and elbow joints.In this study,the kinematics of an SWULRR were analyzed,and the force and motion characteristics of RSPA were studied experimentally.The results provide a reference for the development and application of wearable upper limb rehabilitation robots.An experimental study on the rotation angle of the wrist and the pressure of the RSPA was conducted to test the efect of the rehabilitation training and verify the rationality of the theoretical model.The process of wrist rehabilitation training was tested and evaluated,indicating that SWULRR with RSPAs will enhance the fexibility,comfort,and safety of rehabilitation training.This work is expected to promote the development of wearable upper-limb rehabilitation robots based on modular reinforced soft pneumatic actuators.

Review of Research and Development of Supernumerary Robotic Limbs

Supernumerary robotic limbs(SRLs) are a new type of wearable human auxiliary equipment, which is currently a hot research topic in the world. SRLs have broad applications in many fields, and will provide a reference and technical support for the realization of human-robot collaboration and integration,while playing an important role in improving social security and public services. In this paper, representative SRLs are summarized from the aspects of related literature analysis,research status, ontology structure design, control and driving,sensing and perception, and application fields. This paper also analyzes and summarizes the current technical challenges faced by SRLs, and reviews development progress and key technologies,thus giving a prospect of future technical development trends.

Integrated Hydraulic-Driven Wearable Robot for Knee Assistance

Age-related diseases can lead to knee joint misfunction, making knee assistance necessary through theuse of robotic wearable braces. However, existing wearable robots face challenges in force transmission and humanmotion adaptation, particularly among the elderly. Although soft actuators have been used in wearable robots,achieving rapid response and motion control while maintaining portability remains challenging. To address theseissues, we propose a soft-robotic knee brace system integrated with multiple sensors and a direct-drive hydraulicactuation system. This approach allows for controlled and rapid force output on the portable hydraulic system.The multi-sensor feedback structure enables the robotic system to collaborate with the human body throughhuman physiological signal and body motion information. The human user tests demonstrate that the knee robotprovides assistive torques to the knee joint by being triggered by the electromyography signal and under humanmotion control.

Human-robot interface based on sEMG envelope signal for the collaborative wearable robot

Surface electromyography(sEMG)control interface is a common method for human-centered robotics.Researchers have frequently improved the recognition accuracy of sEMG through multichannel or high-precision signal acquisition devices.However,this increases the cost and complexity of the control system.Therefore,this study developed a control interface based on the sEMG enveloped signal for a collaborative wearable robot to improve the accuracy of sEMG recognition based on the time-domain(TD)features.Specifically,an acquisition device is developed to obtain the sEMG envelope signal,and 11 types of TD features are extracted from the sEMG envelope signal acquired from the upper limb.Furthermore,a dimension reduction method based on the correlation coefficient is proposed,transforming the 11-dimensional feature into a five-dimensional envelope feature set without decreasing the accuracy.Moreover,a recognition algorithm based on a neural network has also been proposed for gesture classification.Finally,the recognition accuracy of the proposed method,principal component analysis(PCA)feature set,and Hudgins TD feature set is compared,with their accuracy at 84.39%,72.44%,and 70.89%,respectively.Therefore,the results indicate that the envelope feature set performs better than the common gesture recognition method based on signal channel sEMG envelope signal.

Development and Evaluation of a Wearable Lower Limb Rehabilitation Robot

This paper introduces a rigid-flexible coupling wearable exoskeleton robot for lower limb,which is designed in light of gait biomechanics and beneficial for low limb movement disorders by implementing gait training.The rationality of the proposed mechanism is shown with the implementation of the dynamic simulation through MSC ADAMS.For the purposes of lightweight,the exoskeleton mechanism is optimized through finite element analysis.It can be concluded from performance evaluation experiment,the mechanism has certain advantages over existing exoskeleton robots,namely,comfortable,lightweight,low cost,which can be utilized for rehabilitation training in medical institutions or as a daily-walking ancillary equipment for patients.

RLSESN-based PID adaptive control for a novel wearable rehabilitation robotic hand driven by PM-TS actuators

Purpose-The purpose of this paper is to develop a novel wearable rehabilitation robotic hand driven by Pneumatic Muscle-Torsion Spring(PM-TS)for finger therapy.PM has complex nonlinear dynamics,which makes PM modelling difficult.To realize high-accurate tracking for the robotic hand,an Echo State Network(ESN)-based PID adaptive controller is proposed,even though the plant model is unknown.Design/methodology/approach-To drive a single joint of rehabilitation robotic hand,the paper proposes a new PM-TS actuator comprising a Pneumatic Muscle(PM)and a Torsion Spring(TS).Based on the novel actuator,a wearable robotic hand is designed.By employing the model-free approximation capability of ESN,the RLSESN based PID adaptive controller is presented for improving the trajectory tracking performance of the rehabilitation robotic hand.An ESN together with Recursive Least Square(RLS)is called a RLSESN,where the ESN output weight matrix is updated by the online RLS learning algorithm.Findings–Practical experiments demonstrate the validity of the PM-TS actuator and indicate that the performance of the RLSESN based PID adaptive controller is better than that of the conventional PID controller.In addition,they also verify the effectiveness of the proposed rehabilitation robotic hand.Originality/value–A new PM-TS actuator configuration that uses a PM and a torsion spring for bi-directional movement of joint is presented.By utilizing the new PM-TS actuator,a novel wearable rehabilitation robotic hand for finger therapy is designed.Based on the unknown plant model,the RLSESN_PID controller is proposed to attain satisfactory performance.

Low-resistance, high-force, and large-ROM fabric-based soft elbow exosuits with adaptive mechanism and composite bellows

Due to the lightweight and compliance, fabric-based pneumatic exosuits are promising in the assistance and rehabilitation of elbow impairments. However, existing elbow exosuits generally suffer from remarkable mechanical resistance on the flexion of the elbow, thus limiting the output force, range of motion(ROM), and comfortability. To address these challenges, we develop a fabric-based soft elbow exosuit with an adaptive mechanism and composite bellows in this work. With the elbow kinesiology considered, the adaptive mechanism is fabricated by sewing the interface of the exosuit into spring-like triangle pleats, following the profile of the elbow to elongate or contract when the elbow flexes or extends. The composite bellows are implemented by further sealing a single blade of bellows into two branches to enhance the output force. Based on these structural features, we characterize the mechanical performance of different soft elbow exosuits: exosuit with normal bellows-NB, exosuit with adaptive mechanism and normal bellows-AMNB, exosuit with adaptive mechanism and composite bellows-AMCB. Experimental results demonstrate that by comparing with NB, the mechanical resistance of AMNB and AMCB decreases by 80.6% and 78.6%, respectively;on the other hand, the output torque of AMNB and AMCB increases to 120.3% and 207.0%, respectively, at50 k Pa when the joint angle is 120°. By wearing these exosuits on a wooden arm model(1.25 kg), we further verify that AMCB can cover a full ROM of 0°–130° at the elbow with 500 g weight. Finally, the application on a health volunteer with AMCB shows that when the volunteer flexes the elbow to lift a weight of 500 g, the s EMG activity of the biceps and triceps is markedly reduced.

An online impedance adaptation controller for decoding skill intelligence

Variable Impedance control allows robots and humans to safely and efficiently interact with unknown external environments.This tutorial introduces online impedance adaptation control(OIAC)for variable compliant joint motions in a range of control tasks:rapid(<1 s)movement control(i.e.,whipping to hit),arm and finger impedance quantification,multifunctional exoskeleton control,and robot-inspired human arm control hypothesis.The OIAC has been introduced as a feedback control,which can be integrated into a feedforward control,e.g.,learned by data-driven methods.This integration facilitates the understanding of human and robot arm control,closing a research loop between biomechanics and robotics.It shows not only a research way from biomechanics to robotics,but also another reserved one.This tutorial aims at presenting research examples and Python codes for advancing the understanding of variable impedance adaptation in human and robot motor control.It contributes to the state-of-the-art by providing an online impedance adaptation controller for wearable robots(i.e.,exoskeletons)which can be used in robotic and biomechanical applications.

Immediate effects of the honda walking assist on spatiotemporal gait characteristics in individuals after stroke

The use of unconstrained lower limb exoskeletons has become a promising approach to assist individuals with gait impairments.The Honda Walking Assist(HWA)is a hip-assistive exoskeleton functioning as a gait trainer and has been shown to improve several gait related outcomes after training.Studies investigating its immediate effects on spatiotemporal gait parameters other than walking speed in stroke survivors are lacking.The aim of this study was to investigate immediate differences in spatiotemporal gait parameters of stroke survivors between normal overground walking,walking with an unpowered,non-assisting HWA and walking with an optimally assisting HWA.Five ischemic stroke survivors(mean time since stroke 115±213.6 days)walked 3 times 5 m in each condition.Differences in 14 spatiotemporal gait parameters between all 3 conditions were registered and reported in a descriptive manner.With optimal assistance,4 patients walked faster(0.057–0.095 m/s)with longer strides of the paretic(0.055–0.069 m)and non-paretic(0.053–0.077 m)leg compared to normal walking.Compared to unpowered walking,all patients walked faster(0.020–0.063 m/s)in the optimal assist condition,with longer strides of the paretic(0.036–0.072 m)and non-paretic leg(0.045–0.082 m).During unpowered walking,gait velocity remained unchanged in 2 patients,increased(0.012_0.051 m/s)in 2 patients and decreased(-0.022 m/s)in 1 patient compared to normal walking.Changes in paretic stride lengths ranged from-0.066 to 0.029 m.The optimal individualized motor assistance provided by the HWA induces small,positive changes in gait parameters.This indicates that this light-weight hip-assistive exoskeleton can be of value in rehabilitation setting,where multiple training sessions with the device are possible.