Walking Assistant Robot Research Articles

Design and Validation of an Ambulatory User Support Gait Rehabilitation Robot: NIMBLE

Relearning to walk requires progressive training in real scenarios—overground—along with assistance in basic tasks, such as balancing. In addition, user ability must be maximized through compliant robotic assistance as needed. Despite decades of research, gait rehabilitation robotic devices yield controversial results. This article presents the conceptual design of a novel walking assistance and rehabilitation robot, the NIMBLE robot, aimed at providing ambulatory, bodyweight-supported gait training, assisting the user’s center of mass trajectory to aid weight transfer and dynamic balance during walking. NIMBLE consists of a robotic mobile frame, a partial bodyweight support (PBWS) system, an ambulatory lower-limb exoskeleton (Exo-H3) and a cable-driven pelvis-assisting robot. Designed as a modular structure, it differentiates hierarchical communication levels through a Robot Operating System (ROS) 2 network. We present the mechatronic design and experimental results assessing the impact of the mechatronic coupling between the robotic modules on the walking kinematics and the frame movement control performance. The robotic frame hardly affects the walking kinematics up to 2 degrees in both the sagittal and frontal planes, making it feasible for lateral balance and weight translation training. Moreover, it successfully tracks and follows user trajectories. The NIMBLE robotic frame assessment shows promising results for ambulatory gait rehabilitation.

Design of foot-wheel cooperation walking assistance robot and control method for human-robot coordination movement

To meet the walking demand of people who is less able to exercise, a foot-wheel cooperation walking assistance robot is designed, a control method of human-robot coordination movement is proposed, and then the walking on-the-wheel system is realized. Firstly, the structure of the foot-wheel cooperation walking assistance robot is designed, the kinematics of human lower limbs is analyzed, and the movement relationship between the foot system and wheel system is established. Secondly, the control methods of the foot system and wheel system are studied respectively, composite control method is used to realize the function that the motion of the human foot is followed by the pedal. Based on the user’s walking information and the motion relationship between the foot system and the wheel system, the coordinated motion control of the foot system and the wheel system is realized. Finally, an experimental prototype of foot-wheel cooperation walking assistance robot is developed, then the foot-wheel cooperation walking assistance experiment is completed. Experimental results show that the function of walking on the wheeled system can be realized by the proposed human-robot coordination movement method.

Control method of elderly-assistant robot for preventing elderly fall

The elderly are prone to fall during walking, which not only leads to injury but also can cause permanent disability or even death. Thus, it is crucial for the walking-assistant robot to prevent the elderly from fall during walking. However, the factors affecting the steadiness of the elderly are not considered comprehensively in the existing studies of elderly fall prevention model and control schemes. In this paper, a novel control method of the elderly-assistant robot for preventing elderly fall is proposed by considering the two main factors affecting steadiness of the elderly, namely, position and velocity of the center of mass. Initially, the dynamics of the robot system for preventing elderly fall are derived respectively from different elderly fall situations. Then, the elderly-assistant robot is controlled to stop at an appropriate position, and to minimize the tilt angle as small as possible to avoid overturned. The control system ensures that the position-velocity coordinates of the center of mass of the elderly reach the dynamic steadiness region which guarantees human balance. Finally, the results of the simulation and the experiments show that the proposed control method of the elderly-assistant robot can be effectively used to prevent the elderly fall during walking.

Influence of gait exercise using a walking-assist robot for swing-leg motion in hemiplegic stroke patients: a preliminary study focusing on the immediate effect.

We analyzed the effect of gait training using a walking-assist robot that assists a subject's knee joint movement and leg swing to achieve toe clearance of the paralyzed-side lower limb during treadmill walking. The subjects were 10 hemiplegic stroke patients in a rehabilitation ward. The intervention consisted of gait training using the Welwalk WW-1000 (Welwalk) robot for 40 min. Immediately before and after this intervention, a gait analysis of the patients' treadmill walking was performed by a three-dimensional motion capture system. Statistical analyses compared the foot-to-floor distance and the shortening of hip-toe length (SHTL) of the paralyzed side before and after the intervention, and examined the relationship between the change of lower-limb joint kinematics and toe clearance before and after the intervention. The post-intervention SHTL was significantly lower compared to before the intervention, and there was a significant negative correlation between the change in the SHTL and the knee flexion angle from before to after the intervention. Gait exercise using the Welwalk could contribute to the acquisition of more normal leg-swing strategies.

Development of Non-wearable Walking Assist Robot for Preventing Falling Accident

Development of Non-wearable Walking Assist Robot for Preventing Falling Accident

The use of walking assistance robot for hemiplegic stroke patient: A Case Report

The use of walking assistance robot for hemiplegic stroke patient: A Case Report

Short-term effect of a close-fitting type of walking assistive device on spinal cord reciprocal inhibition

One of the major problems with walking encountered by patients with spastic hemiplegia is diminished toe clearance due to spasticity of their leg muscles. To improve their walking, a specialized robot assist for ankle movements (RE-Gait) has been utilized. The present study examined the neurophysiological effects whether spinal cord reciprocal Ia inhibition (RI) in the leg was altered by using RE-Gait. Sixteen patients with a clinical diagnosis of stroke were divided into the two groups, RE-Gait walking group (Group R) and normal (controlled) walking group (Group C). In each group, they walked on a flat floor for 15 min with or without RE-Gait. The depression of soleus (Sol) H-reflexes conditioned by common peroneal nerve stimuli with the conditioning-test (C-T) intervals of 1, 2, 3, and 4 ms were assessed before and immediately after each walking session. After the intervention, the LSM (SE) of Sol H-reflex amplitude with 1, 2 and 3 ms C-T interval conditions were significantly decreased in group R (1 ms: 88.15 (4.60), 2 ms: 86.37 (4.60), 3 ms: 89.68 (4.62)) compared to group C (1 ms: 105.57 (4.56), 2 ms: 100.89 (4.58), 3 ms: 107.72 (4.58)) [1 ms: p = 0.012, 2 ms: p = 0.035, 3 ms: p = 0.011]. Walking assistive robot that targets ankle movements might be a new rehabilitation tool for regulating spinal cord excitability.

EEG 신호를 이용한 보행 보조 로봇 이용자의 의도인지 방법

EEG 신호를 이용한 보행 보조 로봇 이용자의 의도인지 방법

텐던구동방식 보행보조로봇의 종아리링크의 무릎관절 토크센서 설계 및 제작

In this paper, the design and fabrication of the calf-link with knee joint torque sensor of a tandem-driven walking-assist robot is described. Tendon-driven walking-assist robots should be designed and constructed with a wire wheel and a torque sensor, as one body to reduce the weight of the calf link. The torque sensor consists of four plate sensing parts crossed 90° around the wire wheel. Structural analysis was performed to determine the size of the torque sensor sensing part, and a torque sensor was built by attaching a strain gauge to the sensing part. As a result of the characteristics test, the reproducibility error and the nonlinearity error of the manufactured torque sensor were less than 0.03% and 0.04%, respectively. As a result of the calibration, the reproducibility error and the nonlinearity error were less than 0.08%, respectively. Thus, it is considered that the knee joint torque sensor of the calf link can be attached to the tandem-driven walking-assist robot.

Research on the Falling Detection System for Elderly-assistant and Walking-assistant Robot

With the development of living standards, the problems caused by aging population have become more and more serious. At the same time, with the growth of age, the body function of the elderly is degenerating and the body flexibility is reducing, which leads to frequently occurring of falling in elderly. The research data shows that falls are the most common and unpredictable problem for old people, which are even life-threatening. Therefore, a falling detection system used in the walking-assistant robot is proposed to make the walking-assistant robot better service during the outdoor walking. Firstly, a general design plan of the falling detection for old people, which is used in walking-assistant robot, is introduced through the analysis of falling mechanism of elderly. Then, a acceleration sensor ADXL345 and the detection module of touch pressure sensors are used to collect data of acceleration and hand touch force of users. Next, the feature extraction is carried out on the above data, and the falling detection is delivered by time domain feature representation and recognition algorithm. At last, the test system is built for test verification, and the results show that the falling detection system has a stable and reliable performance and high detection accuracy rate, reaching 99.05%. It can detect the falling of elderly effectively.

Skill Abstraction of Physical Therapists in Hemiplegia Patient Rehabilitation Using a Walking Assist Robot

Improving the walking functions of hemiplegia patients after a stroke or brain injury is an important rehabilitation challenge. Recently, walking assist robots have been introduced in advanced rehabilitation facilities as a way to improve the efficiency of patient rehabilitation and restore their walking functions. Expert therapists can apply this device on different patients; however, such application mainly depends on the therapist’s tacit knowledge. Thus, it is often harder for novice therapists to apply such devices on different types of patients. Consequently, effective use of a walking assist robot has become a new patient rehabilitation skill. Taking rehabilitation as a service provided by medical doctors or therapists to their patients, this study aims to improve the quality of the rehabilitation service. In particular, the objective of this study is to abstract the rehabilitation skill of expert therapists in using a walking assist robot by applying a service science methodology known as skill education. Skill abstraction was performed by interviewing an expert therapist. From this interview, it was found that the expert therapist classified hemiplegia patients into four different classes. Using videos of patients walking, further analysis revealed the expert’s tacit knowledge, which was indicated by differences observed among these four groups in particular phases of the patients’ walking patterns. This study shows that by successfully obtaining explicit knowledge of part of a rehabilitation skill by using a walking assist robot (which until now was a tacit knowledge of experts), and then organizing the acquired explicit knowledge, even non-experts can easily reproduce the skill of experts in new patient rehabilitation.

Walking Assist Robot: A Novel Non-Contact Abnormal Gait Recognition Approach Based on Extended Set Membership Filter

This work develops intelligent walking assist robot and gait rehabilitation robot for people with walking disabilities, where distinguishing of abnormal gait is crucial during safe human-robot interaction. Although vision sensors and wearable inertial devices are widely used in fall detection system, shielding of robot mechanical structure brings instability for visual detection method, and utilizing a large number of wearable sensors brings discomfort and complexity for users. Meanwhile, the frequent drag-to-drop gait has never been considered, which is a kind of intermittent state between normal state and fall. It's a major challenge to achieve an abnormal gait recognition system with high stability and good comfort. In this paper, a novel non-contact gait recognition method is proposed, which can identify fall and drag-to-drop gait in a stable and comfortable way. Leg movement data is obtained by a built-in-robot camera, which accurately describes gait law through contrast test and error analysis. New-type ESMF algorithm is proposed to evaluate knee angle precisely and resolve the issue of marker point loss effectively. The comprehensive experiments have shown that this innovative approach calculates accurately knee angle in the walking process so as to recognize the phenomenon of drag-to-drop gait and fall. Additionally, this method having a sound theoretical basis and higher stability solves the issue of marker point loss, which could be applied to a walker with a similar structure for elderly and disabled in a comfortable way.

Walking Assist Robot using Light Touch Effect and Evaluation of Walking Pattern

Walking Assist Robot using Light Touch Effect and Evaluation of Walking Pattern

Research on The Control System of The Friendly Walking Assistant Robot for The Elderly

With the intensification of aging population, medical and social insurance system is facing up with the unprecedented pressure. Most of old people need nursing and care. On the one hand, it needs expensive expenditure and manpower. On the other hand, living quality of old people in degree of freedom is greatly reduced. The problem of helping old people to walk has become a great social problem. The self-adaption coordination control of robot is an important indicator of walking assistant robot for the elderly and also the precondition to support and protect old people and the disabled. In order to realize the control of direction for walking assistant robot and get the smaller turning radius and more flexible movement, this paper studied a dual-motor differential control method to realize forward, backward, and cornering of robot. Finally, the experimental results show that the control system of the friendly walking assistant robot for the elderly is rational and feasible, and the designed control system is stable and reliable.

텐던방식을 이용한 착용용 보행보조로봇의 설계 및 제작

텐던방식을 이용한 착용용 보행보조로봇의 설계 및 제작

보행보조로봇의 발목회전력 측정을 위한 발목관절 토크센서 개발

보행보조로봇의 발목회전력 측정을 위한 발목관절 토크센서 개발

Walking Assist Robot: A Novel Approach to Parameter Optimization of a Tracking Controller Compensating for Time Varying Friction

This work develops an intelligent walk assist robot for people with walking disabilities, where the precise tracking of the user’s movement is crucial. The time-varying friction and load changes impose significant challenges on the tracking. Although the digital acceleration controller is effective to handle them, it is difficult and time consuming to manually tune the control parameters for optimal performance. This is why the automatic parameter optimization techniques are popular in the literature. Despite this, the existing parameter tuning algorithms suffer from sub-optimal performance and low computational efficiency. In this paper, an improved genetic algorithm (IGA) is proposed, which can quickly identify the optimal parameters. Our algorithm explores a few advanced genetic mechanisms including nonlinear ranking selection, arithmetic crossover operation method with competition and selection mechanisms among several crossover offspring, and adaptive change of mutation scaling. The simulation and experimental results have shown that this novel IGA algorithm can effectively reduce the tracking error from 18mm to 0.08mm and reduces the computational complexity.

Omniwheel Touchdown Characteristics and Adaptive Saturated Control for a Human Support Robot

With population aging, increasing numbers of people who are elderly are losing the ability to walk and therefore are experiencing difficulties caring for themselves. This prompted the designing of a sitting-type walking-assistance robot named the human support robot (HSR), which can move accurately in narrow indoor environments and act as a person’s legs to assist her/him with activities of daily living. With the construction of a dynamic model of the HSR, a saturated control algorithm guarantees the safety of the omniwheels and the HSR supporting process. Analysis of the omniwheel touchdown characteristics improves the accuracy of the dynamic HSR model. Under trajectory tracking control with adaptive technology, the HSR tracking performance is improved, and the vibration in the orientation angle caused by the omniwheel touchdown characteristics is eliminated. The exponential practical stability of the tracking error system is derived, and the effectiveness of the proposed methods is confirmed in simulations.

Shared Control Design of a Walking-Assistant Robot

This brief presents a control design for a walking-assistant robot in a complex indoor environment, such that it can assist a walking-impaired person to walk and avoid unexpected obstacles. In this design, the robot motion is a resultant of autonomous navigation and compliant motion control. The compliance motion controller allows the robot to possess passive behavior following the motion intent of the user, while the autonomous guidance gives safe navigation of the robot without colliding with any obstacles. A shared-control approach is suggested to combine the passive compliant behavior and safe guidance of the robot. When a user exerts force to the robot, the mobile platform responds to adjust the speed in compliance with the user movement. On the other hand, the autonomous navigation controller is designed to provide collision-free guidance. Using the developed shared controller, outputs of the compliance motion controller and autonomous navigation controller are fused to generate appropriate motion for the robot. In this manner, passive behavior allows the walking-assistant robot to adapt to a user’s motion intent and move in compliance with user. Meanwhile, the active guidance adjusts the linear velocity and the direction of the robot in real time in response to the environmental data received from the on-board laser scanner. The developed algorithms have been implemented on a self-constructed walking-assistant robot. Experimental results validate the proposed design and demonstrate that the robot can actively avoid unexpected obstacles while move passively following the user to the destination.

Safe Guidance for a Walking-Assistant Robot Using Gait Estimation and Obstacle Avoidance

This paper presents a motion control design for a walking-assistant robot by combining passive-compliant behavior and active obstacle avoidance. The proposed method recognizes the intended motion for a user using gait movement and the applied force of a hand. A passive-compliant motion control is developed that allows the user to safely walk with the robot. The obstacle avoidance controller actively controls the velocity to guide the user in a direction that avoids collisions. A shared-control scheme combines active obstacle avoidance and passive-compliant motion commands. The experimental results verify the effectiveness of the proposed method and show that the robot allows a user to walk safely in a complex environment. A questionnaire survey of elderly users shows that the proposed design for a walking-assistant robot gives satisfactory performance.