Design and Analysis of a Smart Rehabilitation Walker With Passive Pelvic Mechanism

Abstract In response to the ever-increasing demand of community-based rehabilitation, a novel smart rehab walker iReGo is designed to facilitate the lower limb rehabilitation training based on motion intention recognition. The proposed walker provides a number of passive degrees-of-freedom (DoFs) to the pelvis that are used to smooth the hip rotations in such a way that the natural gait is not significantly affected, meanwhile, three actuated DoFs are actively controlled to assist patients with mobility disabilities. The walker first identifies the user’s motion intention from the interaction forces in both left and right sides of the pelvis and then uses the kinematic model to generate appropriate driving velocities to support the body weight and improve mobility. In this paper, workspace, dexterity, and the force field of the walker are analyzed based on the system Jacobian. Simulation and experiments with healthy subjects are carried out to verify the effectiveness and tip-over stability. These results demonstrate that the walker has sufficient workspace for pelvic motions, satisfactory dexterity, and near-linear force feedback within the prescribed workspace, and that the walker is easily controlled to ensure normal gait.

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A novel six-legged walking machine tool for in-situ operations

Frontiers of Mechanical Engineering ◽

10.1007/s11465-020-0594-2 ◽

2020 ◽

Vol 15 (3) ◽

pp. 351-364

Author(s):

Jimu Liu ◽

Yuan Tian ◽

Feng Gao

Keyword(s):

Machine Tool ◽

Motion Planning ◽

Kinematic Model ◽

The Body ◽

Body Motion ◽

Walking Distance ◽

Walking Machine ◽

Planning Scheme ◽

Increasing Demand

Abstract The manufacture and maintenance of large parts in ships, trains, aircrafts, and so on create an increasing demand for mobile machine tools to perform in-situ operations. However, few mobile robots can accommodate the complex environment of industrial plants while performing machining tasks. This study proposes a novel six-legged walking machine tool consisting of a legged mobile robot and a portable parallel kinematic machine tool. The kinematic model of the entire system is presented, and the workspace of different components, including a leg, the body, and the head, is analyzed. A hierarchical motion planning scheme is proposed to take advantage of the large workspace of the legged mobile platform and the high precision of the parallel machine tool. The repeatability of the head motion, body motion, and walking distance is evaluated through experiments, which is 0.11, 1.0, and 3.4 mm, respectively. Finally, an application scenario is shown in which the walking machine tool steps successfully over a 250 mm-high obstacle and drills a hole in an aluminum plate. The experiments prove the rationality of the hierarchical motion planning scheme and demonstrate the extensive potential of the walking machine tool for in-situ operations on large parts.

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Fault-Tolerant Tripod Gait Planning and Verification of a Hexapod Robot

Applied Sciences ◽

10.3390/app10082959 ◽

2020 ◽

Vol 10 (8) ◽

pp. 2959

Author(s):

Yiqun Liu ◽

Xuanxia Fan ◽

Liang Ding ◽

Jianfeng Wang ◽

Tao Liu ◽

...

Keyword(s):

Degrees Of Freedom ◽

Fault Tolerant ◽

Kinematic Model ◽

Stability Margin ◽

The Body ◽

Hexapod Robot ◽

Gait Planning ◽

Phase Sequence ◽

Gait Phase ◽

Tripod Gait

In some hazardous or inaccessible applications, such as earthquake rescue, as a substitute for mankind, robots are expected to perform missions reliably. Unfortunately, the failure of components is difficult to avoid due to the complexity of robot composition and the interference of the environment. Thus, improving the reliability of robots is a crucial problem. The hexapod robot has redundant degrees of freedom due to its multiple joints, making it possible to tolerate the failure of one leg. In this paper, the Fault-Tolerant Tripod (F-TT) gait dealing with the failure of one leg is researched. The Denavit–Hartenberg (D-H) method is exploited to establish a kinematic model for the hexapod robot, the Jacobian matrix is analyzed, and it is proved that the body can be controlled when three legs are supported. Then, an F-TT gait phase sequence planning method based on a stability margin is established, and a method to improve stability is proposed. The trajectory for the center of gravity (COG) and foot is studied. Finally, a simulation model and prototype robot experiments are developed, and the effectiveness of the proposed method is verified.

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Design and human–machine compatibility analysis of Co-Exos II for upper-limb rehabilitation

Assembly Automation ◽

10.1108/aa-09-2018-0127 ◽

2019 ◽

Vol 39 (4) ◽

pp. 715-726

Author(s):

Leiyu Zhang ◽

Jianfeng Li ◽

Shuting Ji ◽

Peng Su ◽

Chunjing Tao ◽

...

Keyword(s):

Upper Limb ◽

Degrees Of Freedom ◽

Kinematic Model ◽

Compact Structure ◽

Vertical Movements ◽

Content Type ◽

Upper Limb Rehabilitation ◽

Compatibility Analysis ◽

Configuration Synthesis ◽

Limb Rehabilitation

Purpose Upper-limb joint kinematics are highly complex and the kinematics of rehabilitation exoskeletons fail to reproduce them, resulting in hyperstaticity and human–machine incompatibility. The purpose of this paper is to design and develop a compatible exoskeleton robot (Co-Exos II) to address these problems. Design/methodology/approach The configuration synthesis of Co-Exos II is completed using advanced mechanism theory. A compatible configuration is selected and four passive joints are introduced into the connecting interfaces based on optimal configuration principles. A Co-Exos II prototype with nine degrees of freedom (DOFs) is developed and still owns a compact structure and volume. A new approach is presented to compensate the vertical glenohumeral (GH) movements. Co-Exos II and the upper arm are simplified as a guide-bar mechanism at the elevating plane. The theoretical displacements of passive joints are calculated by the kinematic model of the shoulder loop. The compatible experiments are completed to measure the kinematics of passive joints. Findings The compatible configuration of the passive joints can effectively reduce the gravity influences of the exoskeleton device and the upper extremities. The passive joints exhibit excellent compensation effect for the GH joint movements by comparing the theoretical and measured results. Passive joints can compensate for most GH movements, especially vertical movements. Originality/value Co-Exos II possesses good human–machine compatibility and wearable comfort for the affected upper limbs. The proposed compensation method is convenient to therapists and stroke patients during the rehabilitation trainings.

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A Design Concept and Kinematic Model for a Soft Aquatic Robot with Complex Bio-mimicking Motion

Journal of Bionic Engineering ◽

10.1007/s42235-021-00126-4 ◽

2022 ◽

Author(s):

Shokoofeh Abbaszadeh ◽

Roberto Leidhold ◽

Stefan Hoerner

Keyword(s):

Degrees Of Freedom ◽

Kinematic Model ◽

The Body ◽

Optical Measurements ◽

Fish Mortality ◽

Entire Body ◽

Animal Testing ◽

Live Animal ◽

Complex Deformation ◽

Propulsion Performance

AbstractFish mortality assessments for turbine passages are currently performed by live-animal testing with up to a hundred thousand fish per year in Germany. A propelled sensor device could act as a fish surrogate. In this context, the study presented here investigates the state of the art via a thorough literature review on propulsion systems for aquatic robots. An evaluation of propulsion performance, weight, size and complexity of the motion achievable allows for the selection of an optimal concept for such a fish mimicking device carrying the sensors. In the second step, the design of a bioinspired soft robotic fish driven by an unconventional drive system is described. It is based on piezoceramic actuators, which allow for motion with five degrees of freedom (DOF) and the creation of complex bio-mimicking body motions. A kinematic model for the motion’s characteristics is developed, to achieve accurate position feedback with the use of strain gauges. Optical measurements validate the complex deformation of the body and deliver the basis for the calibration of the kinematic model. Finally, it can be shown, that the calibrated model presented allows the tracking of the deformation of the entire body with an accuracy of 0.1 mm.

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A Force-Feedback Exoskeleton for Upper-Limb Rehabilitation in Virtual Reality

Applied Bionics and Biomechanics ◽

10.1155/2009/378254 ◽

2009 ◽

Vol 6 (2) ◽

pp. 115-126 ◽

Cited By ~ 40

Author(s):

Antonio Frisoli ◽

Fabio Salsedo ◽

Massimo Bergamasco ◽

Bruno Rossi ◽

Maria C. Carboncini

Keyword(s):

Virtual Reality ◽

Upper Limb ◽

Degrees Of Freedom ◽

Force Feedback ◽

Full Range ◽

Upper Limb Rehabilitation ◽

Reaching Task ◽

Human Arm ◽

Performance Error ◽

Limb Rehabilitation

This paper presents the design and the clinical validation of an upper-limb force-feedback exoskeleton, the L-EXOS, for robotic-assisted rehabilitation in virtual reality (VR). The L-EXOS is a five degrees of freedom exoskeleton with a wearable structure and anthropomorphic workspace that can cover the full range of motion of human arm. A specific VR application focused on the reaching task was developed and evaluated on a group of eight post-stroke patients, to assess the efficacy of the system for the rehabilitation of upper limb. The evaluation showed a significant reduction of the performance error in the reaching task (pairedt-test, p < 0.02)

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ARMin III – Arm Therapy Exoskeleton with an Ergonomic Shoulder Actuation

Applied Bionics and Biomechanics ◽

10.1155/2009/962956 ◽

2009 ◽

Vol 6 (2) ◽

pp. 127-142 ◽

Cited By ~ 181

Author(s):

Tobias Nef ◽

Marco Guidali ◽

Robert Riener

Keyword(s):

Degrees Of Freedom ◽

The United States ◽

Rehabilitation Robotics ◽

The Body ◽

Wrist Flexion ◽

Upper Limb Rehabilitation ◽

Rehabilitation Robots ◽

Human Arm ◽

Flexion Extension ◽

Limb Rehabilitation

Rehabilitation robots have become important tools in stroke rehabilitation. Compared to manual arm training, robot-supported training can be more intensive, of longer duration and more repetitive. Therefore, robots have the potential to improve the rehabilitation process in stroke patients. Whereas a majority of previous work in upper limb rehabilitation robotics has focused on end-effector-based robots, a shift towards exoskeleton robots is taking place because they offer a better guidance of the human arm, especially for movements with a large range of motion. However, the implementation of an exoskeleton device introduces the challenge of reproducing the motion of the human shoulder, which is one of the most complex joints of the body. Thus, this paper starts with describing a simplified model of the human shoulder. On the basis of that model, a new ergonomic shoulder actuation principle that provides motion of the humerus head is proposed, and its implementation in the ARMin III arm therapy robot is described. The focus lies on the mechanics and actuation principle. The ARMin III robot provides three actuated degrees of freedom for the shoulder and one for the elbow joint. An additional module provides actuated lower arm pro/supination and wrist flexion/extension. Five ARMin III devices have been manufactured and they are currently undergoing clinical evaluation in hospitals in Switzerland and in the United States.

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The Kinematic Model with Three Degrees of Freedom Associated to the Direct Throwing in Basketball Game

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.658.495 ◽

2014 ◽

Vol 658 ◽

pp. 495-500

Author(s):

Radu Iacob ◽

Emil Budescu ◽

Eugen Merticaru ◽

Cezar Oprişan

Keyword(s):

Degrees Of Freedom ◽

Kinematic Model ◽

Equation System ◽

Angular Speed ◽

The Body ◽

Movement Speed ◽

Body Segments ◽

Geometric Conditions ◽

Basketball Game ◽

Three Degrees Of Freedom

The paper presents a reverse kinematic analysis for the free through to basket in order to determine the possible angular movement speed of the arm segments during throw flexion. The body segments offering three freedom degrees to the kinematic model are: the arm, the forearm and the hand. From geometric conditions regarding to the possibility of the ball to get through the basket and the analysis of the parabolic trajectory of the ball, one could determine the mathematical relations for the limitative values of the horizontal and vertical components of the initial velocity and consequently, for the calculation of the initial angle of throwing the ball. On the other hand, from the expression of the flexion movement of the considered body segments, it could be possible to obtain the calculation of the initial throw velocity as functions of the anthropometric data of the analyzed subject, of flexion angles and angular velocity of movement of the body segments. Using some models of functional mathematic analysis, from the two equations with three unknowns, one could determine the variation field of the system solutions. By setting the conditions related to the numeric limits of variation for the angular speed, the numeric field of the possible solutions for the equation system is straitened.

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Representing utility and deploying the body

Behavioral and Brain Sciences ◽

10.1017/s0140525x19001602 ◽

2020 ◽

Vol 43 ◽

Author(s):

David Spurrett

Keyword(s):

Functional Activity ◽

Degrees Of Freedom ◽

The Body ◽

Target Article ◽

Processing Demands ◽

The Many

Abstract Comprehensive accounts of resource-rational attempts to maximise utility shouldn't ignore the demands of constructing utility representations. This can be onerous when, as in humans, there are many rewarding modalities. Another thing best not ignored is the processing demands of making functional activity out of the many degrees of freedom of a body. The target article is almost silent on both.

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