Design and Control of a Hydraulic-Actuated Leg Exoskeleton for Load-Carrying Augmentation

Cao, Heng; Zhu, Jun; Xia, Chunming; Hong, Zhou; Chen, Xiao; Wang, Yu

doi:10.1007/978-3-642-16584-9_57

Cited by 15 publications

(8 citation statements)

References 6 publications

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“…One of the main aspects to consider in the design of exoskeletons is energy saving, such is the case of NES-1 that—through the design of a mechanism and a gas spring placed below the knee—applies a certain torque to the hip joint for payload support during the stance phase and has an electric actuator in the knee. Likewise, Heng Cao et al 36 implemented a mechanism with a passive support element in the hip joint and a hydraulic element in the knee.…”

Section: Force Augmentation Exoskeletonsmentioning

confidence: 99%

Engineering design strategies for force augmentation exoskeletons: A general review

Martínez-Mata

Ortega

Guzmán-Valdivia

et al. 2023

International Journal of Advanced Robotic Systems

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In the industrial and military sector, work activities are required transporting or supporting heavy loads manually, affecting this the human spinal column due to the weight of the loads or the repetition of this labor. In this regard, the use of force-enhancing exoskeletons is a potential solution to this issue. Therefore, this article summarizes the state of the art in relevant contributions to structural design, control systems, actuators, and performance metrics to evaluate the proper functioning of exoskeletons used for load support and transfer. This is essential to address current and new open problems in these applications, and this includes reducing the metabolic cost and enhancing the loading force in exoskeletons, in which challenges such as structural design and kinetic interactions between the human and the robot are presented. The systematic review of the strategies found in the literature helps addressing these challenges in an orderly way. The proposal of some alternative solutions could help to solving some of the challenges mentioned above, as well as further research to improve the design of these devices is necessary.

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Section: Force Augmentation Exoskeletonsmentioning

confidence: 99%

Engineering design strategies for force augmentation exoskeletons: A general review

Martínez-Mata

Ortega

Guzmán-Valdivia

et al. 2023

International Journal of Advanced Robotic Systems

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“…The exoskeleton is a device that interacts with the human. The main applications of exoskeletons are physical assistance and rehabilitation [1][2][3][4][5][6][7][8][9][10]. During human-machine interaction, under no circumstances should the exoskeleton directly or indirectly cause injury to the human, either in the routine operation or in fault [11].…”

Section: Introductionmentioning

confidence: 99%

“…This method has high accuracy and requires a series of experiments for data acquisition [20][21][22]. The exoskeleton is made up of many non-standard parts, such as pipes and actuators [6][7][8][9][10], which cause the dynamic parameters of the exoskeleton to fluctuate during working. Obviously, it is difficult to obtain the dynamic parameters from the manufacturers or 3D design software.…”

mentioning

confidence: 99%

Dynamic Parameter Identification of a Lower Extremity Exoskeleton Using RLS-PSO

et al. 2019

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The lower extremity exoskeleton is a device for auxiliary assistance of human movement. The interaction performance between the exoskeleton and the human is determined by the lower extremity exoskeleton's controller. The performance of the controller is affected by the accuracy of the dynamic equation. Therefore, it is necessary to study the dynamic parameter identification of lower extremity exoskeleton. The existing dynamic parameter identification algorithms for lower extremity exoskeletons are generally based on Least Square (LS). There are some internal drawbacks, such as complicated experimental processes and low identification accuracy. A dynamic parameter identification algorithm based on Particle Swarm Optimization (PSO) with search space defined by Recursive Least Square (RLS) is developed in this investigation. The developed algorithm is named RLS-PSO. By defining the search space of PSO, RLS-PSO not only avoids the convergence of identified parameters to the local minima, but also improves the identification accuracy of exoskeleton dynamic parameters. Under the same experimental conditions, the identification accuracy of RLS-PSO, PSO and LS was quantitatively compared and analyzed. The results demonstrated that the identification accuracy of RLS-PSO is higher than that of LS and PSO. Appl. Sci. 2019, 9, 324 2 of 17 dynamics of the exoskeleton. Third, obtaining the dynamic parameters through dynamic parameter identification algorithms. This method has high accuracy and requires a series of experiments for data acquisition [20][21][22]. The exoskeleton is made up of many non-standard parts, such as pipes and actuators [6][7][8][9][10], which cause the dynamic parameters of the exoskeleton to fluctuate during working. Obviously, it is difficult to obtain the dynamic parameters from the manufacturers or 3D design software. Therefore, parameter identification algorithms are expected to be an effective way to obtain more accurate dynamic parameters [23,24].In order to obtain more accurate dynamic parameters, researchers are increasingly paying attention to the application of parameter identification algorithms for the exoskeleton. Researchers have carried out some preliminary research works. Targeting the swing phase [25,26], Justin et al. identified the dynamic parameters of Berkeley Exoskeleton (BLEEX) [21] by means of Least Square (LS) [27,28]. The joint friction coefficients of BLEEX were identified by static experiments, and the inertial parameters [29] were identified by dynamic experiments. The method did not make full use of the non-correlation between the parameters and the linear relationship between the parameters and the parameterized dynamic equations [30,31]. Therefore, the method only identified one parameter in each experiment. Designing a corresponding identification experiment for each parameter was necessary. The process of parameter identification experiment was very complicated, and the friction parameters on the hip joint lost identifiability because of the limited range of motion. ...

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“…Many exoskeletons in this direction have been developed, see [4,6,34,2,18] and the references therein. Among them, hydraulic actuators are usually used due to their large values of power/mass ratio, see for instance [26,7,24]. Classic hydraulic actuated exoskeleton examples include Berkeley Lower Extremity Exoskeleton (BLEEX) [38,19], its updated version Human Universal Load Carrier (HULC), and etc.…”

Section: Introductionmentioning

confidence: 99%

A hierarchical Lyapunov-based cascade adaptive control scheme for lower-limb exoskeleton

Zhang

Jiang

Li³

et al. 2019

European Journal of Control

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This paper proposes a hierarchical Lyapunov-based adaptive cascade control scheme for a lower-limb exoskeleton with control saturation. The proposed approach is composed by two control levels with cascade structure. At the higher layer of the structure, a Lyapunov-based back-stepping regulator including adaptive estimation of uncertain parameters and friction force is designed for the leg dynamics, to minimize the deviation of the joint position and its reference value. At the lower layer, a Lyapunov-based neural network adaptive controller is in charge of computing control action for the hydraulic servo system, to follow the force reference computed at the high level, also to compensate for model uncertainty, nonlinearity, and control saturation. The proposed approach shows to be capable in minimizing the interaction torque between machine and human, and suitable for possible imprecise models. The robustness of the closed-loop system is discussed under input constraint. Simulation experiments are reported, which shows that the proposed scheme is effective in imposing smaller interaction torque with respect to PD controller, and in control of models with uncertainty and nonlinearity.

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Design and Control of a Hydraulic-Actuated Leg Exoskeleton for Load-Carrying Augmentation

Cited by 15 publications

References 6 publications

Engineering design strategies for force augmentation exoskeletons: A general review

Engineering design strategies for force augmentation exoskeletons: A general review

Dynamic Parameter Identification of a Lower Extremity Exoskeleton Using RLS-PSO

A hierarchical Lyapunov-based cascade adaptive control scheme for lower-limb exoskeleton

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