Modelling and control of an upper extremity exoskeleton for rehabilitation (original) (raw)
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A hybrid joint based controller for an upper extremity exoskeleton
IOP Conference Series: Materials Science and Engineering, 2016
This paper presents the modelling and control of a two degree of freedom upper extremity exoskeleton. The Euler-Lagrange formulation was used in deriving the dynamic modelling of both the human upper limb as well as the exoskeleton that consists of the upper arm and the forearm. The human model is based on anthropometrical measurements of the upper limb. The proportional-derivative (PD) computed torque control (CTC) architecture is employed in this study to investigate its efficacy performing joint-space control objectives specifically in rehabilitating the elbow and shoulder joints along the sagittal plane. An active force control (AFC) algorithm is also incorporated into the PD-CTC to investigate the effectiveness of this hybrid system in compensating disturbances. It was found that the AFC-PD-CTC performs well against the disturbances introduced into the system whilst achieving acceptable trajectory tracking as compared to the conventional PD-CTC control architecture.
A Robust Controller for Upper Limb Rehabilitation Exoskeleton
Applied Sciences
In this paper, a portable exoskeleton for the rehabilitation of upper extremities of three degrees of freedom (DOF) is proposed. With these degrees of freedom, the exoskeleton provides the movements of flexion–extension and abduction–adduction of the arm and flexion–extension of the forearm. A robust generalized proportional integral (GPI) controller for trajectory tracking to provide smooth movements for rehabilitation with the exoskeleton is proposed. This controller only requires output measurements and is robust against different types of disturbances. Simulation results are presented in the MSC Adams® software environment in co-simulation with Matlab-Simulink® to show the controller’s performance against different types of disturbances. The results of a PID type controller are also contrasted with the results of the GPI controller.
IOP Conference Series: Materials Science and Engineering, 2016
This paper presents the modelling and control of a two degree of freedom upper extremity exoskeleton by means of an intelligent active force control (AFC) mechanism. The Newton-Euler formulation was used in deriving the dynamic modelling of both the anthropometry based human upper extremity as well as the exoskeleton that consists of the upper arm and the forearm. A proportional-derivative (PD) architecture is employed in this study to investigate its efficacy performing joint-space control objectives. An intelligent AFC algorithm is also incorporated into the PD to investigate the effectiveness of this hybrid system in compensating disturbances. The Mamdani Fuzzy based rule is employed to approximate the estimated inertial properties of the system to ensure the AFC loop responds efficiently. It is found that the IAFC-PD performed well against the disturbances introduced into the system as compared to the conventional PD control architecture in performing the desired trajectory tracking.
Mechatronics Design, Modeling and Preliminary Control of a 5 DOF Upper Limb Active Exoskeleton
2016
In this paper, we present the mechatronics design, modeling and preliminary control of a new 5 degrees of freedom (DoF) exoskeleton, dedicated for the upper limb rehabilitation. The designed exoskeleton allows the shoulder rotations as well as the elbow movements. It combines the advantages of both parallel and serial mechanisms. It has been designed by considering the main factors in designing a general use robotic force-feedback device and the human upper limb specications. This active device, as a kind of haptic device, provides two ways communication in both position and force, and allows patients to interact with the virtual reality system and practice activities of daily living (ADL) assistance. The kinematic model of the exoskeleton is presented. In order to evaluate the performance of the exoskeleton, a preliminary position and torque controllers have been implemented.
Force control of upper limb exoskeleton to support user movement
Journal of Mechanical Engineering, Automation and Control Systems, 2020
The dynamics analysis and control of the upper limb exoskeleton for supporting user movement is done by using the force feedforward control model. Based on a novel combination of Proportional Derivative (PD) force feedforward and Proportional Integral (PI) feedback control model [1], this paper proposes a method to assist the user’s movement for a three degree of freedom exoskeleton structure. When the user exerts force at the handle, the force is measured by a force sensor placed at the handle. These sensed forces are applied to command the actuators to support the human movement and reduce the disturbance effects of the device. This technique is well established approach in haptics for reducing the effects of inertia, damping, friction, centrifugal and Coriolis forces and gravity of haptic device [2]. Simulation result shows the torque controlled by robot to assist human for a desired loading motion.
Control of a powered exoskeleton for elbow, forearm and wrist joint movements
2011
To provide passive rehabilitation therapy to individuals with deficits in upper-limb function, we have developed a powered exoskeleton robot, named the MARSE-4. The developed exoskeleton is supposed to be worn on the lateral side of the upper limb and will provide passive arm movement assistance at the level of elbow, forearm and wrist joints. The kinematic model of the exoskeleton was developed based on modified Denavit-Hartenberg notations. In experiments, PID controllers were employed where trajectory tracking that corresponds to typical rehabilitation (passive) exercises were carried out to evaluate the performances of the developed exoskeleton and the controller. Experimental results show that the MARSE-4 can efficiently deliver passive therapy for elbow, forearm and wrist joint movements.
Design and Modelling of a Human Upper Limb for Rehabilitation Exoskeleton
JESTR, 2024
Electromechanical systems that interact with the user to offer power amplification, assistance, or replacement of motor function are known as exoskeletons for the upper limbs. The upper extremity rehabilitation exoskeletons have garnered increasing attention and impact in the healthcare sector over the past years due to the advancements in the field of robotic control devices and actuation elements. The necessity for assistive supporting and rehabilitation devices that either help improve human strengths or provide assistance in regaining lost motion of a specific limb joint arises as a result of changing trends and a growing population. Age-related bone loss often results in weaker, more fragile bones that make lifting and carrying huge loads more difficult. A stroke can impair mobility and is more likely occurs to the elderly people. Accidental paralysis as well as other health issues including spinal cord injuries, musculoskeletal disorders due to work environment are on the rise resulting in an increased urge for the assistive devices. The motive of this paper is to design a mathematical model of the human upper limb involving DH parameters and forward kinematics alongside with the human joint study to precisely design the model in order to design an upper extremity exo-skeleton for offering limb rehabilitation considering the human joint constraints with respect to the Sagittal, Coronal and Transverse planes. This study is aimed in providing a significant vision in developing the precise rehabilitation devices that can aim in offering the joint specific treatment to the user for human upper arm therapy.
Design and Modeling of an Upper Extremity Exoskeleton
IFMBE Proceedings, 2009
This paper presents the design and modeling results of an upper extremity exoskeleton mounted on a wheel chair. This new device is dedicated to regular and efficient rehabilitation training for weak and injured people without the continuous presence of a therapist. The exoskeleton being a wearable robotic device attached to the human arm, the user provides information signals to the controller in order to generate the appropriate control signals for different training strategies and paradigms. This upper extremity exoskeleton covers four basic degrees of freedom of the shoulder and the elbow joints with three additional adaptability degrees of freedom in order to match the arm anatomy of different users.
Force-position control of a robotic exoskeleton to provide upper extremity movement assistance
International Journal of Modelling, Identification and Control, 2014
This paper presents an upper extremity (UE) wearable robot, ETS-MARSE and its control strategy to provide movement assistance and active rehabilitation exercises to physically disabled individuals having impaired UE function. The ETS-MARSE was designed to be worn on the lateral side of UE and is able to assist arm movements at the level of shoulder, elbow, forearm and wrist joint movements. Considering the dynamic modelling of the robot system and the UE motion which are non-linear in nature, a non-linear sliding mode control with exponential reaching law was used to manoeuvre the ETS-MARSE and to provide both passive and assisted arm movement therapy. To provide passive arm movement therapy, pre-programmed trajectories corresponding to recommended passive rehabilitation exercises were used to manoeuvre the ETS-MARSE, whereas in case of assisted rehabilitation therapy user interaction wrist force sensor signals were used to steer the ETS-MARSE in assisting the UE movements. Experiments involving healthy human subjects were performed with the developed ETS-MARSE to evaluate the controller's performance and that of the ETS-MARSE in regards to providing the therapeutic exercises. Experimental results indicate that with the proposed control strategy, ETS-MARSE can effectively deliver rehabilitation exercises.
A New Compound Model-based Control (NCMC) of an Upper Limb Robot for Rehabilitation
International Conference of Control, Dynamic Systems, and Robotics
Human-Robot Interaction (HRI) is considered a benchmark problem in upper limb rehabilitation. Interaction forces between robot and user play a vital role in terms of safety and effectiveness in HRI. Existing robots for upper limb rehabilitation have not considered interaction forces between robot and user in their control algorithm for passive rehabilitation. This may lead to pain and discomfort for patients. To bridge this gap, in this research, a new compound model-based control (NCMC) is proposed where interaction forces at both upper arm and wrist has been incorporated into the control algorithm. Besides, this algorithm deals with the parameter variation of the user (arm length, weight, height) by including an error-driven portion. The Lyapunov stability analysis of the proposed control was carried out to see its stability. The NCMC was implemented on a seven degrees of freedom (DOF) upper limb rehabilitation robot (u-Rob) with an ergonomic shoulder in doing upper limb rehabilitation exercises with healthy subjects. The experimental results show the effectiveness of the proposed control and validate the stability of the proposed control approach.