Stiffness Analysis of Parallel Cable-Driven Upper Limb Rehabilitation Robot

Zou, Yupeng; Wu, Xiangshu; Zhang, Baolong; Zhang, Qiang; Zhang, Andong; Qin, Tao

doi:10.3390/mi13020253

Cited by 6 publications

(3 citation statements)

References 27 publications

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“…At different stages of their rehabilitation, patients need different training modalities, requiring a specific stiffness from the rehabilitation robot ( Zou et al, 2022 ). In order to increase the effectiveness of rehabilitation therapy assisted by rehabilitation robot, patients’ active participation must be encouraged by the robot controller ( Luo et al, 2017 ; Guo et al, 2022a ).…”

Section: Methodsmentioning

confidence: 99%

Research on adaptive impedance control technology of upper limb rehabilitation robot based on impedance parameter prediction

Zhang,

Li,

Tao

et al. 2024

Front. Bioeng. Biotechnol.

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Introduction: With the aggravation of aging and the growing number of stroke patients suffering from hemiplegia in China, rehabilitation robots have become an integral part of rehabilitation training. However, traditional rehabilitation robots cannot modify the training parameters adaptively to match the upper limbs’ rehabilitation status automatically and apply them in rehabilitation training effectively, which will improve the efficacy of rehabilitation training.Methods: In this study, a two-degree-of-freedom flexible drive joint rehabilitation robot platform was built. The forgetting factor recursive least squares method (FFRLS) was utilized to estimate the impedance parameters of human upper limb end. A reward function was established to select the optimal stiffness parameters of the rehabilitation robot.Results: The results confirmed the effectiveness of the adaptive impedance control strategy. The findings of the adaptive impedance control studies showed that the adaptive impedance control had a significantly greater reward than the constant impedance control, which was in line with the simulation results of the variable impedance control. Moreover, it was observed that the levels of robot assistance could be suitably modified based on the subject’s different participation.Discussion: The results facilitated stroke patients’ upper limb rehabilitation by enabling the rehabilitation robot to adaptively change the impedance parameters according to the functional status of the affected limb. In clinic therapy, the proposed control strategy may help to adjust the reward function for different patients to improve the rehabilitation efficacy eventually.

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Section: Methodsmentioning

confidence: 99%

Research on adaptive impedance control technology of upper limb rehabilitation robot based on impedance parameter prediction

Zhang,

Li,

Tao

et al. 2024

Front. Bioeng. Biotechnol.

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“…The disadvantage of this structure is that the cable transmission accuracy is low and it is easy to entangle. 22 In terms of control, initially HIVMTS used a cable tension control strategy, such as the four cable space virtual motion robot designed by Laval University in Canada, which can simulate collisions between objects of different shapes and has three DOF 23 ; Zou et al analyzed the stiffness of the astronaut training system and improved the tension control strategy based on the system stiffness to enhance smoothness 24 ; And the parallel cable driven virtual robot which has improved in terms of workspace and control accuracy was designed by the team in which the author participated. 25 The systems that use this control strategy in other fields include the variable stiffness parallel cable drive mechanism designed by Zhang et al 26 The parallel series hybrid joint proposed by them has the characteristics of light structure and large workspace.…”

Section: Related Work and Objectives Of This Researchmentioning

confidence: 99%

An all-position type control strategy of the haptic interactive virtual training system based on cable-driven

Xue,

Zhang,

Wang

et al. 2024

Advances in Mechanical Engineering

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The virtual microgravity training system based on cable drive usually uses a force-position hybrid control strategy which has following problems: the force control method is sensitive to load disturbances, variable stiffness characteristics of cables reduce the control accuracy of PID controllers, and the expected tension fluctuations are large. These will affect the control accuracy, and further affect the tactile sensation and training effectiveness of astronauts. For the above problems, an all-position type control strategy is proposed to improve the system control accuracy. This strategy uses a compliant control method. In this method, elastic elements are connected in cables, the conversion model of tension and displacement is established, and the tension control is realized by the displacement control which has characteristics of high control accuracy and strong resistance to load disturbance. The PID controller is replaced by the active disturbance rejection controller. In this controller, the tracking differentiator is used to reduce high frequency noises of the input signal, and the extended state observer is used to estimate and compensate the error caused by the change of the cable stiffness. A tension distribution method is designed to make expected cable tensions approach the average tension to reduce the tension fluctuation. The experimental results show that compared with the force-position hybrid control strategy, the all-position type control strategy reduces the tension error and speed error by about 51% and 33% respectively.

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“…The principle of the cable tension control strategy is that all cables are controlled by a force servo, and the desired motion law is realized by controlling the resultant force acting on the end effector. Zou, YP designed an astronaut training system and analyzed the stiffness of the cable drive system [21]. The team that the author was a member of conducted research on cable-driven on-orbit physical exercise equipment for astronauts [22].…”

Section: Introductionmentioning

confidence: 99%

A New Composite Control Strategy for an Astronaut Virtual Operation Training System Based on Cable-Driven Technology

Xue,

Zhang,

et al. 2023

Actuators

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In recent years, virtual microgravity training technology for astronauts based on cable-driven designs has emerged, and it solves the following problems: high costs, short training times, and low safety of existing equipment. However, this technology does not solve the reduced motion accuracy problem of the operated object due to the elastic deformation of cables, and this problem will reduce the operational experience of astronauts during training. In view of this problem, a cable-driven virtual operation training system for astronauts is designed, and a new composite control strategy based on parallel cables is proposed, which effectively improves motion control accuracy by allocating cable tension and using a tension compliance control method to suppress the influence of cable deformation. In addition, the desired tension of cables is optimized based on the system’s workspace so that the system can achieve more complex virtual microgravity training tasks. Finally, verification via experiments demonstrated that the training system and the new composite control strategy are effective.

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Stiffness Analysis of Parallel Cable-Driven Upper Limb Rehabilitation Robot

Cited by 6 publications

References 27 publications

Research on adaptive impedance control technology of upper limb rehabilitation robot based on impedance parameter prediction

Research on adaptive impedance control technology of upper limb rehabilitation robot based on impedance parameter prediction

An all-position type control strategy of the haptic interactive virtual training system based on cable-driven

A New Composite Control Strategy for an Astronaut Virtual Operation Training System Based on Cable-Driven Technology

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