scholarly journals Design of a 4-DOF grounded exoskeletal robot for shoulder and elbow rehabilitation

2020 ◽  
Vol 2 (1) ◽  
pp. 41-65
Author(s):  
Fatih Karadeniz ◽  
Özgür Ege Aydoğan ◽  
Emin Abdullah Kazancı ◽  
Erhan Akdogan

The number of cerebrovascular and neuromuscular diseases is increasing in parallel with the rising average age of the world’s population. Since the shoulder anatomy is complex, the number of rehabilitation robots for shoulder movements is limited. This paper presents the mechanical design, control, and testing of a 4 degrees of freedom (DOF) grounded upper limb exoskeletal robot. It is capable of four different therapeutic exercises (passive, active assistive, isotonic and isometric). During the mechanical design, the forces to be exposed to the robot were determined and after the design, the system was tested with strength analysis. Also, a low-cost electromyograph device was developed and integrated into the system to measure muscular activation for feedback and instantaneously muscle activation control for the physiotherapist during the therapy. The system can be used for rehabilitation on the shoulder and elbow.  A PID controller for position-controlled exercises were developed. The test results were presented in terms of simulation and the real system for passive exercise. According to the test results, the developed system can perform passive exercise and can be used for other therapeutic exercises as well.

2015 ◽  
Vol 17 (1) ◽  
pp. 79-90 ◽  
Author(s):  
Juan Francisco Ayala Lozano ◽  
Guillermo Urriolagoitia Sosa ◽  
Beatriz Romero Ángeles ◽  
Christopher René Torres San-Miguel ◽  
Luis Antonio Aguilar-Pérez ◽  
...  

<strong>Título en ingles: Mechanical design of an exoskeleton for upper limb rehabilitation</strong><p><strong>Título corto: Diseño mecánico de un exoesqueleto</strong></p><p><strong>Resumen:</strong> El ritmo de vida actual, tanto sociocultural como tecnológico, ha desembocado en un aumento de enfermedades y padecimientos que afectan las capacidades físico-motrices de los individuos. Esto ha originado el desarrollo de prototipos para auxiliar al paciente a recuperar la movilidad y la fortaleza de las extremidades superiores afectadas. El presente trabajo aborda el diseño de una estructura mecánica de un exoesqueleto con 4 grados de libertad para miembro superior. La cual tiene como principales atributos la capacidad de ajustarse a la antropometría del paciente mexicano (longitud del brazo, extensión del antebrazo, condiciones geométricas de la espalda y altura del paciente). Se aplicó el método <em>BLITZ QFD</em> para obtener el diseño conceptual óptimo y establecer adecuadamente las condiciones de carga de servicio. Por lo que, se definieron 5 casos de estudio cuasi-estáticos e implantaron condiciones para rehabilitación de los pacientes. Asimismo, mediante el Método de Elemento Finito (MEF) se analizaron los esfuerzos y deformaciones a los que la estructura está sometida durante la aplicación de los agentes externos de servicio. Los resultados presentados en éste trabajo exhiben una nueva propuesta para la rehabilitación de pacientes con problemas de movilidad en miembro superior. Donde el equipo propuesto permite la rehabilitación del miembro superior apoyado en 4 grados de libertad (tres grados de libertad en el hombro y uno en el codo), el cual es adecuado para realizar terapias activas y pasivas. Asimismo, es un dispositivo que está al alcance de un mayor porcentaje de la población por su bajo costo y fácil desarrollo en la fabricación.</p><p><strong>Palabras clave:</strong> MEF, Blitz QFD, exoesqueletos, diseño mecánico.</p><p><strong>Abstract</strong>: The pace of modern life, both socio-cultural and technologically, has led to an increase of diseases and conditions that affect the physical-motor capabilities of persons. This increase has originated the development of prototypes to help patients to regain mobility and strength of the affected upper limb. This work, deals with the mechanical structure design of an exoskeleton with 4 degrees freedom for upper limb. Which has the capacity to adjust to the Mexican patient anthropometry (arm length, forearm extension, geometry conditions of the back and the patient’s height) BLITZ QFD method was applied to establish the conceptual design and loading service conditions on the structure.  So, 5 quasi-static cases of study were defined and conditions for patient rehabilitation were subjected. Also by applying the finite element method the structure was analyzed due to service loading. The results presented in this work, show a new method for patient rehabilitation with mobility deficiencies in the upper limb. The proposed new design allows the rehabilitation of the upper limb under 4 degrees of freedom (tree degrees of freedom at shoulder and one at the elbow), which is perfect to perform active and passive therapy. Additionally, it is an equipment of low cost, which can be affordable to almost all the country population.</p><p><strong>Key words:</strong> FEM, Blitz QFD, exoskeletons, mechanical design<strong>.</strong></p><p><strong>Recibido:</strong> agosto 20 de 2014   <strong>Aprobado:</strong> marzo 26 de 2015</p>


Author(s):  
Wong-Jong Kim ◽  
Shobhit Verma ◽  
Jie Gu

This paper presents a novel magnetically levitated (maglev) stage with nanoscale positioning capability in all six degrees of freedom (DOFs). The key aspect of this device is that its single moving part has no mechanical contact with its stationary base, which leads to no mechanical friction and stiction, and no wear particle generation. We present herein the mechanical design, instrumentation, and test results of this maglev stage. Currently it shows position resolution of 4 nm, position noise of 2 nm rms, hundreds-of-micrometer translational travel range, a-few-milliradian rotational travel range, and power consumption less than a fraction of a Watt per axis. This maglev stage can be used in numerous applications such as manufacture of nanoscale structures, assembly and packaging on micro-size parts, vibration isolation for delicate instrumentation, and telepresence microsurgery.


Author(s):  
Dilshad A. Sulaiman ◽  
Akash B. Pandey

This paper provides the design of a simple robotic arm for pick and place operations as well as other material handling operations. The movements of the arm are anthropometric i.e. resembling the human arm with respect to degrees of freedom so as to provide a human touch in industrial and space operations. This system operates using controlled motion of DC geared motors along with a microcontroller based system (8051 or PIC based). Use of PWM (Pulse Width Modulation) can be used to control the RPM of DC geared motors. This system has the advantage of being simple and low cost with a varied flexibility of operation. A collective array of sensors viz. voice sensor, infrared light sensors, proximity sensors etc. can be incorporated to form a feedback induced closed loop system. Whereas for tasks of picking and placing at a fixed location from another location the system can be operational at open-loop. The material for the robotic arm can be polypropylene or acrylic or aluminium to reduce weight without compromising on the strength and lifting capacity of the robotic arm, such that the torque of the DC geared motors (actuators) at each joint are sufficient to lift the arm along with the weight at the end effector. Clutch and gear shifting mechanism can be used to increase the degrees of freedom per actuator. The driving circuit mainly consists of the microcontroller and H-bridge drivers using an 8-bit port to control 4 DC geared motors per port simultaneously or one at a time using delay commands. DC geared motors are quite cheaper than stepper motors and RC Servos thus reducing the total cost of the system drastically. Plus being light weight, DC geared motors reduce the total weight of the system. This paper will also throw light on the programming aspects for the microcontroller (8051 or PIC based) along with the compatible flash programmers and HEX code generators. This project will further explain on the approach followed in the mechanical design of the robotic arm (motion, work volume etc.) as well as the possible future applications of the robotic arm. Also the design of the robotic arm on CAD tools like Solidworks will be discussed in brief along with the modeling and simulation of the various links of the arm as well as the whole assembly of the system. With increasing popularity of Automation, robotic arms are the present and future of all industrial operations. Finally the paper concludes on the further improvements in design and technology.


2021 ◽  
Vol 11 (13) ◽  
pp. 6116
Author(s):  
Vítor H. Pinto ◽  
Inês N. Soares ◽  
Marco Rocha ◽  
José Lima ◽  
José Gonçalves ◽  
...  

This paper presents a legged-wheeled hybrid robotic vehicle that uses a combination of rigid and non-rigid joints, allowing it to be more impact-tolerant. The robot has four legs, each one with three degrees of freedom. Each leg has two non-rigid rotational joints with completely passive components for damping and accumulation of kinetic energy, one rigid rotational joint, and a driving wheel. Each leg uses three independent DC motors—one for each joint, as well as a fourth one for driving the wheel. The four legs have the same position configuration, except for the upper hip joint. The vehicle was designed to be modular, low-cost, and its parts to be interchangeable. Beyond this, the vehicle has multiple operation modes, including a low-power mode. Across this article, the design, modeling, and control stages are presented, as well as the communication strategy. A prototype platform was built to serve as a test bed, which is described throughout the article. The mechanical design and applied hardware for each leg have been improved, and these changes are described. The mechanical and hardware structure of the complete robot is also presented, as well as the software and communication approaches. Moreover, a realistic simulation is introduced, along with the obtained results.


2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
José-Alfredo Leal-Naranjo ◽  
Christopher-René Torres-San Miguel ◽  
Marco Ceccarelli ◽  
Horacio Rostro-Gonzalez

This work presents the design of a low-cost prosthetic device for shoulder disarticulation. A proper design of the mechanisms has been addressed to obtain a prototype that presents 7 degrees of freedom. Shoulder movement is achieved by means of a spherical parallel manipulator, elbow movement is performed by a six-bar mechanism, and the wrist movement is implemented by a spherical parallel manipulator. A set of dynamic simulations was performed in order to assess the functionality of the design. The prototype was built using 3D printing techniques and implementing low-cost actuators. An experimental evaluation was carried out to characterize this device. The result of this work is a prototype that weighs 1350 g that is able to perform movements related to activities of daily living.


Author(s):  
Dilshad A. Sulaiman ◽  
Akash B. Pandey

This paper provides the design of a simple robotic arm for pick and place operations as well as other material handling operations. The movements of the arm are anthropometric i.e. resembling the human arm with respect to degrees of freedom so as to provide a human touch in industrial and space operations. This system operates using controlled motion of DC geared motors along with a microcontroller based system (8051 or PIC based). Use of PWM (Pulse Width Modulation) can be used to control the RPM of DC geared motors. This system has the advantage of being simple and low cost with a varied flexibility of operation. A collective array of sensors viz. voice sensor, infrared light sensors, proximity sensors etc. can be incorporated to form a feedback induced closed loop system. Whereas for tasks of picking and placing at a fixed location from another location the system can be operational at open-loop. The material for the robotic arm can be polypropylene or acrylic or aluminium to reduce weight without compromising on the strength and lifting capacity of the robotic arm, such that the torque of the DC geared motors (actuators) at each joint are sufficient to lift the arm along with the weight at the end effector. Clutch and gear shifting mechanism can be used to increase the degrees of freedom per actuator. The driving circuit mainly consists of the microcontroller and H-bridge drivers using an 8-bit port to control 4 DC geared motors per port simultaneously or one at a time using delay commands. DC geared motors are quite cheaper than stepper motors and RC Servos thus reducing the total cost of the system drastically. Plus being light weight, DC geared motors reduce the total weight of the system. This paper will also throw light on the programming aspects for the microcontroller (8051 or PIC based) along with the compatible flash programmers and HEX code generators. This project will further explain on the approach followed in the mechanical design of the robotic arm (motion, work volume etc.) as well as the possible future applications of the robotic arm. Also the design of the robotic arm on CAD tools like Solidworks will be discussed in brief along with the modeling and simulation of the various links of the arm as well as the whole assembly of the system. With increasing popularity of Automation, robotic arms are the present and future of all industrial operations. Finally the paper concludes on the further improvements in design and technology.


Author(s):  
Luis Arturo Gómez Malagón ◽  
João Luiz Vilar Dias
Keyword(s):  

2021 ◽  
Vol 11 (13) ◽  
pp. 5865
Author(s):  
Muhammad Ahsan Gull ◽  
Mikkel Thoegersen ◽  
Stefan Hein Bengtson ◽  
Mostafa Mohammadi ◽  
Lotte N. S. Andreasen Struijk ◽  
...  

Wheelchair mounted upper limb exoskeletons offer an alternative way to support disabled individuals in their activities of daily living (ADL). Key challenges in exoskeleton technology include innovative mechanical design and implementation of a control method that can assure a safe and comfortable interaction between the human upper limb and exoskeleton. In this article, we present a mechanical design of a four degrees of freedom (DOF) wheelchair mounted upper limb exoskeleton. The design takes advantage of non-backdrivable mechanism that can hold the output position without energy consumption and provide assistance to the completely paralyzed users. Moreover, a PD-based trajectory tracking control is implemented to enhance the performance of human exoskeleton system for two different tasks. Preliminary results are provided to show the effectiveness and reliability of using the proposed design for physically disabled people.


Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2459
Author(s):  
Rubén Tena Sánchez ◽  
Fernando Rodríguez Varela ◽  
Lars J. Foged ◽  
Manuel Sierra Castañer

Phase reconstruction is in general a non-trivial problem when it comes to devices where the reference is not accessible. A non-convex iterative optimization algorithm is proposed in this paper in order to reconstruct the phase in reference-less spherical multiprobe measurement systems based on a rotating arch of probes. The algorithm is based on the reconstruction of the phases of self-transmitting devices in multiprobe systems by taking advantage of the on-axis top probe of the arch. One of the limitations of the top probe solution is that when rotating the measurement system arch, the relative phase between probes is lost. This paper proposes a solution to this problem by developing an optimization iterative algorithm that uses partial knowledge of relative phase between probes. The iterative algorithm is based on linear combinations of signals when the relative phase is known. Phase substitution and modal filtering are implemented in order to avoid local minima and make the algorithm converge. Several noise-free examples are presented and the results of the iterative algorithm analyzed. The number of linear combinations used is far below the square of the degrees of freedom of the non-linear problem, which is compensated by a proper initial guess. With respect to noisy measurements, the top probe method will introduce uncertainties for different azimuth and elevation positions of the arch. This is modelled by considering the real noise model of a low-cost receiver and the results demonstrate the good accuracy of the method. Numerical results on antenna measurements are also presented. Due to the numerical complexity of the algorithm, it is limited to electrically small- or medium-size problems.


Author(s):  
Murat Fidan ◽  
Alper Bayrak ◽  
Umid Karli

In this study, a low-cost and adaptable isometric strength measurement and exercise development system are described. The implemented system consists of mechanical structure, force measurement sensor, electronic circuit, and computer software. Isometric-isotonic (via spring resistance) strength analysis and various exercise programs can be applied with the system. The developed system has a lower cost compared to its counterparts in the literature and has a structure that can be adapted to different machines and measuring methods. The operability and reliability of the isometric strength measurement and exercise development system have been proven by calibration tests.


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