Powering a Lower Limb Exoskeleton Using Pneumatic Artificial Muscles

2016 ◽  
Author(s):  
Jonathan M. Chambers ◽  
Craig R. Carignan ◽  
Norman M. Wereley
Keyword(s):  
Knee Joint ◽  
Lower Limb ◽  
Kinematic Model ◽  
Knee Joints ◽  
Transmission Model ◽  
Artificial Muscles ◽  
Lower Limb Exoskeleton ◽  
Actuation System ◽  
Pneumatic Artificial Muscles ◽  
Assembly Tasks

Passive leg exoskeletons are currently being investigated for offsetting the weight of tools and other loads from workers performing maintenance and assembly tasks. By providing power-assist to the knee joints with pneumatic artificial muscles (PAMs), a wider range of stances could be used by maintenance workers without drawing significant power. A simplified kinematic model of the exoskeleton is developed, and the array of potential user stance configurations is then bounded. A static analysis is performed to define the torque required for actuation of the knee joint to support the tool loads carried by the exoskeleton. Finally, an exemplary transmission model is used to verify that it is feasible for a PAM to provide the range of motion and forces required for knee joint actuation. Upon demonstration of the viability of PAM actuation, development of an exoskeleton leg prototype is underway to provide validation of the proposed scheme. The knee actuation system will be retrofit to the FORTIS exoskeleton, and tests on its effectiveness will be conducted.

scholarly journals Powered Upper Limb Orthosis Actuation System Based on Pneumatic Artificial Muscles

2018 ◽  
Vol 48 (1) ◽  
pp. 23-36 ◽  
Author(s):  
Dimitar Chakarov ◽  
Ivanka Veneva ◽  
Mihail Tsveov ◽  
Pavel Venev
Keyword(s):  
Upper Limb ◽  
Joint Stiffness ◽  
Artificial Muscles ◽  
Joint Motion ◽  
Robot Interaction ◽  
Pneumatic Actuators ◽  
Joint Torques ◽  
Actuation System ◽  
Pneumatic Muscles ◽  
Pneumatic Artificial Muscles

AbstractThe actuation system of a powered upper limb orthosis is studied in the work. To create natural safety in the mutual “man-robot” interaction, an actuation system based on pneumatic artificial muscles (PAM) is selected. Experimentally obtained force/contraction diagrams for bundles, consisting of different number of muscles are shown in the paper. The pooling force and the stiffness of the pneumatic actuators is assessed as a function of the number of muscles in the bundle and the supply pressure. Joint motion and torque is achieved by antagonistic actions through pulleys, driven by bundles of pneumatic muscles. Joint stiffness and joint torques are determined on condition of a power balance, as a function of the joint position, pressure, number of muscles and muscles

scholarly journals Design and Control of a 1-DOF Robotic Lower-Limb System Driven by Novel Single Pneumatic Artificial Muscle

2019 ◽  
Vol 10 (1) ◽  
pp. 43 ◽  
Author(s):  
Tsung-Chin Tsai ◽  
Mao-Hsiung Chiang
Keyword(s):  
Lower Limb ◽  
Artificial Muscle ◽  
Robotic System ◽  
Artificial Muscles ◽  
Prototype System ◽  
Pneumatic Artificial Muscle ◽  
Torsion Spring ◽  
Pneumatic Artificial Muscles ◽  
Control Response ◽  
Spring Mechanism

This study determines the practicality and feasibility of the application of pneumatic artificial muscles (PAMs) in a pneumatic therapy robotic system. The novel mechanism consists of a single actuated pneumatic artificial muscle (single-PAM) robotic lower limb that is driven by only one PAM combined with a torsion spring. Unlike most of previous studies, which used dual-actuated pneumatic artificial muscles (dual-PAMs) to drive joints, this design aims to develop a novel single-PAM for a one degree-of-freedom (1-DOF) robotic lower-limb system with the advantage of a mechanism for developing a multi-axial therapy robotic system. The lower limb robotic assisting system uses the stretching/contraction characteristics of a single-PAM and the torsion spring designed by the mechanism to realize joint position control. The joint is driven by a single-PAM controlled by a proportional pressure valve, a designed 1-DOF lower-limb robotic system, and an experimental prototype system similar to human lower limbs are established. However, the non-linear behavior, high hysteresis, low damping and time-variant characteristics for a PAM with a torsion spring still limits its controllability. In order to control the system, a fuzzy sliding mode controller (FSMC) is used to control the path tracking for the PAM for the first time. This control method prevents approximation errors, disturbances, un-modeled dynamics and ensures positioning performance for the whole system. Consequently, from the various experimental results, the control response designed by the joint torsion spring mechanism can also obtain the control response like the design of the double-PAMs mechanism, which proves that the innovative single-PAM with torsion spring mechanism design in this study can reduce the size of the overall aid mechanism and reduce the manufacturing cost, can also improve the portability and convenience required for the wearable accessory, and is more suitable for the portable rehabilitation aid system architecture.

Lower Limb Exoskeleton Design Based on Knee Joint Assistance

2021 ◽  
Author(s):  
Peng Jiang ◽  
Ye Wang ◽  
Tianqi Shao ◽  
Changsoo Han ◽  
Lin Wang ◽  
...  
Keyword(s):  
Knee Joint ◽  
Lower Limb ◽  
Lower Limb Exoskeleton ◽  
Exoskeleton Design

An Anthropometrically Parameterized Assistive Lower-limb Exoskeleton

2021 ◽  
Author(s):  
Curt Laubscher ◽  
Ryan Farris ◽  
Antonie van den Bogert ◽  
Jerzy T. Sawicki
Keyword(s):  
Lower Limb ◽  
Muscle Activation ◽  
Vastus Lateralis ◽  
Mechanical Energy ◽  
Biceps Femoris ◽  
Knee Joints ◽  
Lower Limb Exoskeleton ◽  
Hip Abduction ◽  
The Subject ◽  
Muscle Activations

Abstract This paper presents a newly developed lower-limb exoskeleton tested for walking assistance. The novel exoskeleton design methodology uses additive manufacturing and a parametrized model based on user anthropometrics to give a person-specific custom fit. The process is applied to average children and a healthy adult, and a prototype device is fabricated for the adult to validate the feasibility of the approach. The developed prototype actuates the hip and knee joints without restricting hip abduction-adduction motion. To test usability of the device and evaluate walking assistance, user torque, mechanical energy generated, and muscle activation are analyzed in an assisted condition where the subject walks on a level treadmill with the exoskeleton powered. This is compared to an unassisted condition with the exoskeleton unpowered and a baseline condition with the subject not wearing the exoskeleton. Comparing assisted to baseline conditions, torque magnitudes increased at the hip and knee, mechanical energy generated increased at the hip but decreased at the knee, and muscle activations decreased in the Biceps Femoris and increased in the Vastus Lateralis. The presented preliminary results are inconclusive on whether the newly developed exoskeleton can assist in walking though show promise for basic usability of the device.

scholarly journals Robotic Exoskeleton Control for Lower Limb Rehabilitation of Knee Joint

2018 ◽  
Vol 7 (2.34) ◽  
pp. 56 ◽  
Author(s):  
Syed Faiz Ahmed ◽  
M Kamran Joyo ◽  
Athar Ali ◽  
Abdul Malik M. Ali ◽  
Kushsairy A. Kadir ◽  
...  
Keyword(s):  
Knee Joint ◽  
Lower Limb ◽  
Control Strategies ◽  
Stroke Recovery ◽  
Robotic Systems ◽  
Lower Limb Exoskeleton ◽  
Limb Rehabilitation ◽  
Future Work ◽  
Lower Limb Rehabilitation ◽  
Rehabilitation Robotic

Wearable devices such as exoskeletons are being opted frequently during rehabilitation processes for the post stroke recovery. Such devices are playing important role in the development of assistive rehabilitation robotic systems. In this paper three control strategies MPC and LQR and PID are introduced which were applied to knee joint of lower limb exoskeleton model for passive exercise. The two controls MPC and LQR are model based control which empowers them for stable responses. In this paper the analysis of robustness of control is done under the noisy and disturbance conditions. The results showed good performance of the exoskeleton model with the applied controls in the provided condition. In the future work the applied controls will be implemented on hardware.

Passive and Active Control Strategies of a Leg Rehabilitation Exoskeleton Powered by Pneumatic Artificial Muscles

2017 ◽  
Vol 31 (10) ◽  
pp. 1759021 ◽  
Author(s):  
Chen Su ◽  
Ao Chai ◽  
Xikai Tu ◽  
Hongyu Zhou ◽  
Haiqiang Wang ◽  
...  
Keyword(s):  
Lower Limb ◽  
Sliding Mode ◽  
Control Strategies ◽  
Low Cost ◽  
Gait Training ◽  
Interaction Force ◽  
Gait Rehabilitation ◽  
Artificial Muscles ◽  
Model Free ◽  
Pneumatic Artificial Muscles

Nerve injury can cause lower limb paralysis and gait disorder. Currently lower limb rehabilitation exoskeleton robots used in the hospitals need more power to correct abnormal motor patterns of stroke patients’ legs. These gait rehabilitation robots are powered by cumbersome and bulky electric motors, which provides a poor user experience. A newly developed gait rehabilitation exoskeleton robot actuated by low-cost and lightweight pneumatic artificial muscles (PAMs) is presented in this research. A model-free proxy-based sliding mode control (PSMC) strategy and a model-based chattering mitigation robust variable control (CRVC) strategy were developed and first applied in rehabilitation trainings, respectively. As the dynamic response of PAM due to the compressed air is low, an innovative intention identification control strategy was taken in active trainings by the use of the subject’s intention indirectly through the estimation of the interaction force between the subject’s leg and the exoskeleton. The proposed intention identification strategy was verified by treadmill-based gait training experiments.

Design and validation of a lower limb exoskeleton employing the recumbent cycling modality for post-stroke rehabilitation

2014 ◽  
Vol 228 (18) ◽  
pp. 3517-3525 ◽  
Author(s):  
Hua Yan ◽  
Canjun Yang
Keyword(s):  
Lower Limb ◽  
Muscle Power ◽  
Sagittal Plane ◽  
Kinematic Model ◽  
Stroke Patients ◽  
Post Stroke ◽  
Lower Limb Exoskeleton ◽  
Exoskeleton Robot ◽  
Limited Range Of Motion ◽  
Custom Made

This paper presents the design and validation of a lower limb exoskeleton robot for post-stroke patients at the early stage of neurorehabilitation. Instead of the usual walking gait, the popular exercise, recumbent cycling, is adopted to provide a safe and comfortable movement training to the patients who lost active motor abilities due to a very low muscle power. The exoskeleton robot mounted on a commercial wheelchair possesses two pairs of hip and knee joints on the right and left legs, respectively, and each joint has one degree of freedom actuated by a custom-made linear actuator in the sagittal plane. Additionally, two passive ankle joints are added to provide a limited range of motion for human comfort. The hip and knee joint motion profiles were calculated based on a simplified kinematic model of the recumbent cycling modality, and implemented through the motor position–velocity–time trajectory. Clinical trials were conducted on six stable post-stroke patients with a low muscle power under the supervision of a skilled therapist. The preliminary results validated the functionality and feasibility of the new exoskeleton robot and showed a promising application of the recumbent cycling modality in robot-assisted neurorehabilitation.

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