Robust Position Control of a Knee-Joint Rehabilitation Exoskeleton Using a Linear Matrix Inequalities-Based Design Approach

Applied Sciences, Journal Year: 2025, Volume and Issue: 15(1), P. 404 - 404

Published: Jan. 4, 2025

This study focuses on developing a control methodology for exoskeleton robots designed lower limb rehabilitation, specifically addressing the needs of elderly individuals and pediatric therapy. The approach centers implementing an affine state-feedback controller to effectively regulate stabilize knee-joint robot at desired position. robot’s dynamics are nonlinear, accounting unknown parameters, solid viscous frictions, external disturbances. To ensure robust stabilization, Lyapunov is utilized derive set Linear Matrix Inequality (LMI) conditions, guaranteeing stability position error. derivation these LMI conditions grounded in comprehensive theoretical framework that employs advanced mathematical tools, including matrix inversion lemma, Young’s inequality, Schur complement, S-procedure, specific congruence transformations. Simulation results presented validate proposed demonstrating effectiveness strategy achieving accurate positioning rehabilitation robotic system.

Language: Английский

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An LMI-based robust state-feedback controller design for the position control of a knee rehabilitation exoskeleton robot: Comparative analysis

Measurement and Control, Journal Year: 2024, Volume and Issue: unknown

Published: March 25, 2024

Rehabilitation exoskeleton robots play a crucial role in restoring functional lower limb movements for individuals with locomotor disorders. Numerous research studies have concentrated on adapting the control of these rehabilitation robotic systems. In this study, we investigate an affine state-feedback law robust position knee robot, taking into account its nonlinear dynamic model that includes solid and viscous frictions. To ensure stabilization, employ Lyapunov approach propose three methods to establish stability conditions using Schur complement, Young inequality, matrix inversion lemma, S-procedure lemma. These are formulated as Linear Matrix Inequalities (LMIs). Furthermore, conduct comprehensive comparison among determine most efficient approach. At end work, present simulation results validate developed LMI demonstrate effectiveness adopted achieving robot.

Language: Английский

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Design and preliminary validation of a compatible lower limb exoskeleton with variable stiffness actuation

Robotica, Journal Year: 2025, Volume and Issue: unknown, P. 1 - 16

Published: April 10, 2025

Abstract Compliant and safe human–robot interaction is an important requirement in lower limb exoskeleton design. Motivated by this need, paper presents the design of a compatible with variable stiffness actuation anthropomorphic joint mechanisms, for walking assistance gait rehabilitation. A novel actuator (VSA) based on guide-bar mechanism was designed, to provide force impedance controllability. By changing crank length mechanism, adjusted wide range (from 0 1301 Nm/rad), at fast speed (about 2582 Nm/rad/s), low-energy cost. These features make it possible online adjustment during one cycle, change coupling behavior improve performance exoskeleton. An hip designed parallelogram linkage passive compensation approach, which absorbs misalignment improves kinematic compatibility between human joint. Furthermore, torque control-based multimode control strategy, consists mode, active hybrid developed different disease stages. Finally, verified benchtop test, experimental validations subject were carried out, demonstrate that compliant achieved, variation benefits improvement when mode changes.

Language: Английский

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Enhancing Knee Rehabilitation Exoskeleton Control via a Robust LMI-Based Strategy and by Considering State Constraints

Published: Dec. 18, 2023

This study introduces a robust control strategy to regulate the position of knee rehabilitation exoskeleton robot. A description this particular robotic system and its nonlinear dynamic model are outlined first. The faces challenges such as state constraints, external disruptions, parameter uncertainties, all which meticulously addressed in design. Subsequently, we define affine state-feedback controller design based on LMI approach, aimed at ensuring stabilization active joint level hence stability desired position. To achieve this, our proposed method utilizes quadratic Lyapunov function leverages mathematical tools S-procedure Lemma, Schur complement, matrix inversion Young inequality derive finally two conditions that guarantee controlled system. Finally, simulation studies validate effectiveness approach condition efficiency

Language: Английский

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LMI-Based Design of a Robust Affine Control Law for the Position Control of a Knee Exoskeleton Robot: Comparative Analysis of Stability Conditions

Published: Dec. 1, 2023

Rehabilitation exoskeleton robots have emerged as valuable tools for restoring functional lower limb movements in individuals afflicted with locomotor impairments. Our innovative approach is centered on the use of a linear state-feedback control strategy, meticulously designed to achieve precise over knee exoskeleton's position, even face complex dynamics and challenges posed by presence frictions, uncertain parameters, external disturbances. To this goal, we will rely Lyapunov methodology, allowing us develop three distinct methods establishing stability conditions. These conditions are presented form Linear Matrix Inequalities (LMIs). We also conducted thorough comparative analysis assess efficiency these methods. As conclude research, fortified our findings comprehensive simulations, which offer solid evidence effectiveness law achieving an efficient robust stabilization robot.

Language: Английский

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A method for analyzing wearing uncertainties and enhancing motion transmission smoothness in exoskeletons and its applications for a novel passive knee exoskeleton

Mechanism and Machine Theory, Journal Year: 2024, Volume and Issue: 197, P. 105648 - 105648

Published: April 11, 2024

Language: Английский

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A Robust LMI-Based Approach for the Position Control of a 1-DoF Knee Rehabilitation Exoskeleton Robot Considering State Constraints

Published: March 14, 2024

This study introduces a robust control strategy designed for one-degree-of-freedom (1-DoF) knee rehabilitation exoskeleton robot. Focusing on position control, our approach addresses challenges such as state constraints, parameter uncertainties, solid and viscous frictions, external disturbances. To achieve this goal, we propose an affine state-feedback controller. Additionally, utilizing quadratic Lyapunov function, establish some Linear Matrix Inequality (LMI) stability conditions the matrix gain of adopted controller to ensure stabilization robot desired position. These are developed using mathematical tools congruence transformations. Finally, results presented show validity efficiency in achieving 1-DoF robot, even under uncertainties

Language: Английский

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Multi-mode adaptive control strategy for a lower limb rehabilitation robot

Frontiers in Bioengineering and Biotechnology, Journal Year: 2024, Volume and Issue: 12

Published: May 16, 2024

Different patients have different rehabilitation requirements. It is essential to ensure the safety and comfort of at recovery stages during training. This study proposes a multi-mode adaptive control method achieve safe compliant training strategy. First, patients' motion intention motor ability are evaluated based on average human-robot interaction force per task cycle. Second, three kinds modes-robot-dominant, patient-dominant, safety-stop-are established, controller can dexterously switch between modes. In robot-dominant mode, errors, patient's ability, intention, adaptively adjust its assistance level impedance parameters help complete tasks encourage them actively participate. patient-dominant only adjusts speed. When trajectory error too large, switches safety-stop mode patient safety. The stabilities under modes then proven using Lyapunov theory. Finally, effectiveness verified by simulation results.

Language: Английский

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Gait self-learning control based on reference trajectory generation online for an asymmetric limb rehabilitation exoskeleton

Mechatronics, Journal Year: 2024, Volume and Issue: 104, P. 103262 - 103262

Published: Oct. 9, 2024

Language: Английский

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Design and Evaluation of a Novel Variable Stiffness Hip Joint Exoskeleton

Sensors, Journal Year: 2024, Volume and Issue: 24(20), P. 6693 - 6693

Published: Oct. 17, 2024

An exoskeleton is a wearable device with human-machine interaction characteristics. ideal should have kinematic and kinetic characteristics similar to those of the wearer. Most traditional exoskeletons are driven by rigid actuators based on joint torque or position control algorithms. In order achieve better human-robot interaction, flexible been introduced into exoskeletons. However, fixed stiffness cannot adapt changing requirements during assistance. collaborative torque, bionic variable hip (BVS-HJE) designed in this article. The proposed article inspired muscles that come agonist-antagonist pairs, whose arranged an antagonistic form both sides joint. Compared other exoskeletons, it has mechanisms, which allow independent force (or position) control. A BVS-HJE model was established study its static Based BVS-HJE, strategy can adjustment stiffness. addition, mechanism estimate output mathematical through encoder, thus eliminating additional sensors process. Finally, properties actuator controllability were verified experiments.

Language: Английский

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