Design Of Rehabilitation Robot Research Articles

Design and Passive Training Control of Elbow Rehabilitation Robot

In this paper, a rehabilitation robot driven by multifilament muscles is designed based on the rehabilitation robot motion model and a system elbow joint model. The passive training mode of rehabilitation robots were researched, and active disturbance rejection control (ADRC) leveraged to improve the tracking angle of robot joints. In the no-load motion simulation of rehabilitation robots, disturbances are added to the control variables to complete the ADRC and Proportional Integral Differential (PID) position control simulation. The simulation results indicate that the auto disturbance rejection control can quickly keep up the expected signal without overshoot, solve the contradiction between the system rapidity and overshoot. Moreover, it can better suppress the interference even if the external load changes. The upper limbs of the human body are used as the load on the robot body to complete the simulation of ADRC and PID position control objects of different weights. Finally, a passive rehabilitation training experiment was conducted to verify the safety of the rehabilitation robot, the rationality, comfort, and robustness of the mechanism design, and the effectiveness and feasibility of the ADRC.

Design and evaluation of a surface electromyography-controlled lightweight upper arm exoskeleton rehabilitation robot

Nowadays, the rehabilitation robot has been developed for rehabilitation therapy. However, there are few studies on upper arm exoskeletons for rehabilitation training of muscle strength. This article aims to design a surface electromyography-controlled lightweight exoskeleton rehabilitation robot for home-based progressive resistance training. The exoskeleton’s lightweight structure is designed based on the kinematic model of the elbow joint and ergonomics sizes of the arm. At the same time, the overall weight of the exoskeleton is controlled at only 3.03 kg. According to the rehabilitation training task, we use torque limit mode to ensure stable torque output at variable velocity. We also propose a surface electromyography-based control method, which uses k- Nearest Neighbor algorithm to classify surface electromyographic signals under progressive training loads, and utilizes principal component analysis to improve the recognition accuracy to control the exoskeleton to provide muscle strength compensation. The assessment experiment of the exoskeleton rehabilitation robot shows that the dynamic recognition accuracy of this control method is 80.21%. Muscle activity of biceps brachii and triceps brachii under each training load decreases significantly when subjects with the exoskeleton robot. The results indicate that the exoskeleton rehabilitation robot can output the corresponding torque to assist in progressive resistance training. This study provides a solution to potential problems in the family-oriented application of exoskeleton rehabilitation robots.

Kinematics analysis and scale optimization of four degree of freedom generalized spherical parallel mechanism for ankle joint rehabilitation

By analyzing the physiological structure and motion characteristics of human ankle joint, a four degree of freedom generalized spherical parallel mechanism is proposed to meet the needs of ankle rehabilitation. Using the spiral theory to analyze the motion characteristics of the mechanism and based on the method of describing the position with spherical coordinates and the posture with Euler Angle, the inverse solution of the closed vector equation of mechanism position is established. The workspace of mechanism is analyzed according to the constraint conditions of inverse solution. The workspace of the moving spherical center of the mechanism is used to match the movement space of the tibiotalar joint, and the workspace of the dynamic platform is used to match the movement space of subtalar joint. Genetic algorithm is used to optimize the key scale parameters of the mechanism. The results show that the workspace of the generalized spherical parallel mechanism can satisfy the actual movement space of human ankle joint rehabilitation. The results of this paper can provide theoretical basis and experimental reference for the design of ankle joint rehabilitation robot with high matching degree.

Design of an Ankle Rehab Robot With a Compliant Parallel Kinematic Mechanism

Abstract In this article, we present the design of a novel ankle rehabilitation robot (ARR), called the Flex-ARR, that employs a compliant parallel kinematic mechanism (PKM) with decoupled degrees-of-freedom. While multiple ARRs have been developed and commercialized, their clinical adoption has been limited primarily because they do not emulate the natural motion of the ankle. Based on a review of existing ARRs and their limitations, this article defines functional requirements and design specifications for an optimal ARR. These are then used to develop a design strategy followed by conceptual and detailed design of a novel ARR. The proposed Flex-ARR is designed to collocate the biological center of rotation of the ankle with that of the robot's center of rotation to allow natural ankle motion. The strategic use of a compliant PKM in the Flex-ARR not only absorbs any residual misalignment between these two centers but also helps inherently accommodate variations in user foot sizes with minimal adjustments. Detailed design includes the ARR structure with adjustable features, compliant PKM optimization, sensor and actuator selection, and an alignment tool.

Mechanism Design and Analysis of a Multi-DOF Flexible Ankle Rehabilitation Robot

According to the needs of global social development, this paper briefly describes the design and modelling of an ankle rehabilitation robot. A multi degree-of-freedom (DOF) ankle rehabilitation robot mechanism is constructed by using flexible pneumatic muscle actuators. The relevant mainstream control methods are analyzed. On this basis, we integrate the ankle rehabilitation robot with virtual reality technology and functional electrical stimulation technology, to further improve the participation of patients and improve the efficiency of ankle rehabilitation.

Configuration Design of an Upper Limb Rehabilitation Robot with a Generalized Shoulder Joint

For stroke patients with upper limb motor dysfunction, rehabilitation training with the help of rehabilitation robots is a social development trend. Existing upper limb rehabilitation robots have difficulty fully fitting the complex motion of the human shoulder joint and have poor human–robot compatibility. In this paper, based on the anatomical structure of the human upper limb, an equivalent mechanism model of the human upper limb is established. The configuration synthesis of the upper limb rehabilitation mechanism was carried out, a variety of shoulder joint man–machine closed-chain Θs and shoulder elbow human–machine closed-chain Θse configuration combinations were synthesized, and the configuration model with compatibility and reduced moment conduction attenuation was selected from them. Two configurations, 2Pa1P3Ra and 5Ra1P, are proposed for the generalized shoulder joint mechanism of the robot. The closed-chain kinematic models of the two configurations are established, and the velocity Jacobian matrix is obtained. Motion performance analysis, condition reciprocal analysis and operability ellipsoid analysis of different configuration design schemes were carried out in different operation planes. The results show that in the normal upper limb posture of the human body, the 5Ra1P configuration of the shoulder joint has better kinematic performance. Finally, on this basis, an upper limb rehabilitation robot prototype with good human–computer compatibility is developed, and its moving space was verified.

Retracted: Design and Workspace Analysis of a Parallel Ankle Rehabilitation Robot (PARR).

[This retracts the article DOI: 10.1155/2019/4164790.].

New Hybrid AD Methodology for Minimizing the Total Amount of Information Content: A Case Study of Rehabilitation Robot Design

Converting customer needs into specific forms and providing consumers with services are crucial in product design. Currently, conversion is no longer difficult due to the development of modern technology, and various measures can be applied for product realization, thus increasing the complexity of analysis and evaluation in the design process. The focus of the design process has thus shifted from problem solving to minimizing the total amount of information content. This paper presents a New Hybrid Axiomatic Design (AD) Methodology based on iteratively matching and merging design parameters that meet the independence axiom and attribute constraints by applying trimming technology, the ideal final results, and technology evolution theory. The proposed method minimizes the total amount of information content and improves the design quality. Finally, a case study of a rehabilitation robot design for hemiplegic patients is presented. The results indicate that the iterative matching and merging of related attributes can minimize the total amount of information content, reduce the cost, and improve design efficiency. Additionally, evolutionary technology prediction can ensure product novelty and improve market competitiveness. The methodology provides an excellent way to design a new (or improved) product.

Design, analysis and experiment of finger soft actuator with nested structure for rehabilitation training

Compared with the rigid hand rehabilitation robot, the soft hand rehabilitation robot has the advantages of good flexibility, which is of great significance to its research. In order to make the soft hand rehabilitation robot have the advantages of high stiffness and simple manufacturing process, a nested structure is proposed for finger soft actuator in this paper. The nested structure consists of outer restraint structure and inner core structure. The inner core structure can realize deformation under the action of air pressure. The outer restraint structure can improve bending efficiency by restraining deformation in non-functional direction of inner core structure. On this basis, the processing technology of nested structure is designed, and the effect of structural parameters on performance is analyzed. In order to illustrate the advantages of nested structure, the performance of nested structure and fiber-constrained structure is compared by simulation, which includes bending angle, gripping force and expansion amount (by measuring the deformation of the cross section). The simulation results show the advantages of the nested structure. A prototype of the soft hand rehabilitation robot is developed with nested structure as finger soft actuator, and the experimental results prove the feasibility of design. The results of this study provide a reference for the structure design of soft hand rehabilitation robot.

Design and fabrication of a passive upper limb rehabilitation robot with adjustable automatic balance based on variable mass of end-effector

The purpose of this work is to design and fabricate a balanced passive robotic arm with the capability of applying variable mass to the end-effector in order to upper limb rehabilitation. To achieve this purpose, the first step is associated with establishing a robot structural design in the CAD environment. The next step is focused on developing the kinematic model based on the degrees of freedom and joint range of motion of the lower legs. Thereafter, the potential energy functions are determined for the springs and weight of components applied in the mechanism. The genetic algorithm is employed as a proper optimization program to extract the system design parameters, including the spring stiffness coefficients and their placement positions within the system. A prototype is fabricated for a balanced robot, and the end-effector mass variations are utilized to develop an adjustable balance capability. To create balance in the system, several items are designed, consisting of a control panel, two electric motors, and an electronic processor. This situation provides an equivalent force equal to the weight of selected mass from the end-effector to the user’s hand. (It is done by a reverse process.) The actual mass required for robot balance is compared to the mass defined in the simulation environment. The evaluation results indicate that it is possible to create an optimized balance by using the simulation outputs.

Parametric design optimization of an ankle rehabilitation robot using SolidWorks

This paper presents the approach to determine most suitable dimensions and volume of the proposed ankle rehabilitation robot design. This design aim is the robot needs to be portable without compromising the workspace of the proposed robot and it must fulfill all required basic ankle motions. To do this, optimisation was used to generate possible initial dimensions in order to achieve suitable length for the outer frame through minimization of the dimensions. Based on the selected variables and constraints, the result of the optimization shows minimization of the proposed design has been achieved through reduction of the dimension of the outer frame of the robot in which translate the reduction of the weight of the robot.

Design and control of a lower limb rehabilitation robot considering undesirable torques of the patient's limb.

This research introduces a new exoskeleton-type rehabilitation robot, which can be used in lower limb rehabilitation therapy for post-stroke patients. A novel design of a typical knee and ankle rehabilitation robot is proposed. The kinematic and dynamic models of the knee and ankle rehabilitation robot are derived. Furthermore, a super-twisting nonsingular terminal sliding mode control is developed to achieve the desired training missions and its results are compared with those of an adaptive sliding mode control. To reduce undesired interaction torques between knee and ankle rehabilitation robot and patient, an admittance control algorithm is added to the controller to guarantee a safe therapy session. The admittance super-twisting nonsingular terminal sliding mode control structure is considered as the novelty of this article. Taking into account the dynamic uncertainties, external disturbances, and the interaction torques, the validity of the admittance super-twisting nonsingular terminal sliding mode control controller is approved by various numerical simulations over the admittance adaptive sliding mode control.

A Modified Kinematic Model of Shoulder Complex Based on Vicon Motion Capturing System: Generalized GH Joint with Floating Centre.

Due to the complex coupling motion of shoulder mechanism, only a small amount of quantitative information is available in the existing literature, although various kinematic models of the shoulder complex have been proposed. This study focused on the specific motion coupling relationship between glenohumeral (GH) joint center displacement variable quantity relative to the thorax coordinate system and humeral elevation angle to describe the shoulder complex. The mechanism model of shoulder complex was proposed with an algorithm designed. Subsequently, twelve healthy subjects performed right arm raising, lowering, as well as raising and lowering (RAL) movements in sixteen elevation planes, and the motion information of the markers attached to the thorax, scapula, and humerus was captured by using Vicon motion capturing system. Then, experimental data was processed and the generalized GH joint with floating center was quantized. Simultaneously, different coupling characteristics were detected during humerus raising as well as lowering movements. The motion coupling relationships in different phases were acquired, and a modified kinematic model was established, with the description of overall motion characteristics of shoulder complex validated by comparing the results with a prior kinematic model from literature, showing enough accuracy for the design of upper limb rehabilitation robots.

High-Density Surface Electromyogram-based Biometrics for Personal Identification.

Surface electromyogram (sEMG) has been widely applied in neurorehabilitation techniques such as human-machine interface (HMI). The individual difference of sEMG characteristics has long been a challenge for multi-user HMI. However, the individually unique sEMG property indicates its high potential as a biometrics modality. In this work, we propose a novel application of high-density sEMG (HD-sEMG) for personal identification. HD-sEMG can decode the high-resolution spatial patterns of muscle activations, besides the widely studied temporal features, thus providing more sufficient information. We acquired 64-channel HD-sEMG signals on the dorsum of the right hand from 22 subjects during finger muscle isometric contractions. We achieved an accuracy of 99.5% to recognize the identity of each subject, demonstrating the excellent performance of HD-sEMG for personal identification. To the best of our knowledge, this is the first study to employ HD-sEMG for personal identification.Clinical relevance-Our work has proved the huge individual difference of HD-sEMG, which may result from the individually unique bioelectrophysiological activity of human body, deriving from both neural and biomechanical factors. The investigation of subject-specific HD-sEMG pattern may contribute to a better design of subject-specific clinical rehabilitation robots and a deeper understanding of human movement mechanism.

Design and control of soft rehabilitation robots actuated by pneumatic muscles: State of the art

Robot-assisted rehabilitation has become a new mainstream trend for the treatment of stroke patients with movement disability. Pneumatic muscle (PM) is one of the most promising actuators for rehabilitation robots, due to its inherent compliance and safety features. In this paper, we conduct a systematic review on the soft rehabilitation robots driven by pneumatic muscles. This review discusses up to date mechanical structures and control strategies for PMs-actuated rehabilitation robots. A variety of state-of-the-art soft rehabilitation robots are classified and reviewed according to the actuation configurations. Special attentions are paid to control strategies under different mechanical designs, with advanced control approaches to overcome PM’s highly nonlinear and time-varying behaviors and to enhance the adaptability to different patients. Finally, we analyze and highlight the current research gaps and the future directions in this field, which is potential for providing a reliable guidance on the development of advanced soft rehabilitation robots.

Joint design and torque feedback experiment of rehabilitation robot

The performance of the real-time dynamic force and torque compensation, flexible force interactive control, and the ability to compensate for the defect of the passive rehabilitation training are the important functions within the rehabilitation robot design process. In this investigation, the upper limb rehabilitation robot is designed, and the force sensor is used to measure the joint feedback torque with high precision, high sensitivity, and low cost. In the rehabilitation robot design process, the human–machine adaptability and lightweight flexible driving design are considered, and the static and dynamic moment detection performances of the driving joint are analyzed. Furthermore, the impedance control algorithm is used to control the force output of the single drive joint, and then the sinusoidal force output performance and step force output performance are tested under different amplitudes and frequencies. Finally, the passive rehabilitation mode of the prototype is tested to evaluate the performance of the rehabilitation robot. The results show that the force output accuracy and stability of the driving joint has a good performance, which can satisfy the force-assisted application of exoskeleton.

Design and Analysis of a Wearable Upper Limb Rehabilitation Robot with Characteristics of Tension Mechanism

Nowadays, patients with mild and moderate upper limb paralysis caused by cerebral apoplexy are uncomfortable with autonomous rehabilitation. In this paper, according to the “rope + toothed belt” generalized rope drive design scheme, we design a utility model for a wearable upper limb rehabilitation robot with a tension mechanism. Owing to study of the human upper extremity anatomy, movement mechanisms, and the ranges of motion, it can determine the range of motion angles of the human arm joints, and design the shoulder joint, elbow joint, and wrist joint separately under the principle of ensuring the minimum driving torque. Then, the kinematics, workspace and dynamics analysis of each structure are performed. Finally, the control system of the rehabilitation robot is designed. The experimental results show that the structure is convenient to wear on the human body, and the robot’s freedom of movement matches well with the freedom of movement of the human body. It can effectively support and traction the front and rear arms of the affected limb, and accurately transmit the applied traction force to the upper limb of the joints. The rationality of the wearable upper limb rehabilitation robot design is verified, which can help patients achieve rehabilitation training and provide an effective rehabilitation equipment for patients with hemiplegia caused by stroke.

State-of-the-Art Robotic Devices for Wrist Rehabilitation: Design and Control Aspects

Robot-assisted physical therapy of the upper limb is becoming popular among the rehabilitation community. The wrist is the second most complicated joint in the upper limb after shoulder in terms of degrees of freedom. Several robotic devices have been developed during the past three decades for wrist joint rehabilitation. Intensive physical therapy and repetitive self-practice, with objective measurement of performance, could be provided by using these wrist rehabilitation robots at a low cost. There has been an increasing trend in the development of wrist rehabilitation robots to provide safe and customized therapy according to the disability level of patients. The mechanical design and control paradigms are two active fields of research undergoing rapid developments in the field of robot-assisted wrist rehabilitation. The mechanical design of these robots could be divided into the categories of end-effector based robots and wearable robotic orthoses. The control for these wrist rehabilitation robots could also be divided into the conventional trajectory tracking control mode and the assist-as-needed control mode for providing customized robotic assistance. This article presents a review of the mechanical design and control aspects of wrist rehabilitation robots. Experimental evaluations of these robots with healthy and neurologically impaired are also discussed along with the future directions of research in the design and control domains of wrist rehabilitation robots.

A User Motion Data Acquisition and Processing Method for the Design of Rehabilitation Robot With Few Degrees-of-Freedom

Abstract Mechanism with few degrees-of-freedom is an economical solution for rehabilitation robots because it does not need a complicated structure and control system. To provide motion data to design the robot with few degrees-of-freedom, a user motion data acquisition, and processing method on the mobile platform is proposed. The data from the monocular vision system have been used on the smartphone and the KCF algorithm to track the knee and hip joints motion. To increase the stability and the precision, the maker with texture is designed to carry out the tracking. Furthermore, the transformation from the image coordinate to the world coordinate is implemented by the cross-ratio invariant in the controlled tracking condition with fixed dimension makers. By this mean, the motion path in the image coordinate is converted to that in the world coordinate. With the low limb motion path that provides the input of the Fourier descriptor, the mechanical parameters of the robot with few degrees-of-freedom are calculated, and the 3D models of the mechanism are constructed. Finally, the prototype of the rehabilitation robot is established which can assist the users to stand from sitting posture, or work as a wheelchair with obstacle avoidance function by infrared and ultrasonic sensors.

Design and performance analysis of a parallel wrist rehabilitation robot (PWRR)

Wrist rehabilitation robots are essential for assisting patients with stoke or wrist injuries. Such devices compensate for deficiencies in manual rehabilitation training, and reduce the workload of rehabilitation physicians. A parallel wrist rehabilitation robot (PWRR) driven by two pneumatic actuators is developed in this paper, consisting of two rotational degrees of freedom for the movements of flexion/extension (F/E) and radial/ulnar deviation (R/U). All components connected to the forearm or the wrist adopt an open structure to improve the wearable convenience, and the PWRR is suitable for most patients, especially those with hypertonia. To determine the PWRR range of motion, the physiological motion space (PMS) of the wrist joint in autonomous and boundary elliptical movements is measured with the help of a VICON motion capture system. The PMS in boundary motions processes an elliptical shape, and the ulnar deviations occupy the most range of motion. The theoretical workspace (TWS) of PWRR is then calculated and designed based on the kinematic model and the distribution characteristics of PMS. In addition, two indices are introduced to evaluate the kinematic performance of PWRR. A PWRR prototype is developed based on the optimal geometrical parameters and detailed structures. Its effective workspace (EWS), which has more clinical significance, is acquired by measuring the F/E and R/U movements during autonomic movements. The EWS, is smaller than TWS due to the physical structure, volume, and interference of mechanical elements. Besides, EWS can nearly encircle PMS, and satisfies all single-axis rehabilitations and compound motions of the wrist complex. The two indices, motion isotropy da and condition number κ, within TWS change smoothly with no mutation, suggesting that PWRR is sufficiently kinematically isotropic, and has no singularity configuration. The analysis shows that the developed PWRR can be applied widely in the wrist rehabilitation.