Soft Robotic Rehabilitation Exoskeleton (REHAB Glove) for Hand Therapy

2017 ◽  
Author(s):  
Mahdi Haghshenas-Jaryani ◽  
Caleb Nothnagle ◽  
Rita M. Patterson ◽  
Nicoleta Bugnariu ◽  
Muthu B. J. Wijesundara
Keyword(s):  
Control Algorithm ◽  
Position Control ◽  
Angular Position ◽  
Healthy Individuals ◽  
Hand Rehabilitation ◽  
Robotic Rehabilitation ◽  
Angular Velocities ◽  
Controlled Motion ◽  
Actuator Design ◽  
Flexion And Extension

This paper presents the design, control, and validation of a soft robotic exoskeleton system, the REHAB Glove, for hand rehabilitation. The system is comprised of five hybrid soft-and-rigid robotic digits that apply controlled flexion and extension motion to fingers. The previous actuator design of the soft robotic digit was improved for kinematic compatibility with anatomical motions of the hand in relation to range of motion, center of rotation, and dorsal skin lengthening. The design was validated using motion capture and analysis. A position control algorithm, which controls finger angular trajectories (angular position and velocity), was developed based on motion sensor feedback. The operation of this algorithm was verified using a 90° digit tip trajectory with two angular velocities of 15°/sec and 30°/sec. A pilot study was carried out with five healthy individuals to evaluate the performance of the REHAB Glove in providing therapeutic schemes. The results show that the REHAB Glove is able to provide controlled motion compatible with the kinematics and dynamics of the human.

Patient-Driven Hand Exoskeleton Based Robotic with Active Control System for Early Post Stroke Rehabilitation

2015 ◽  
Vol 799-800 ◽  
pp. 1063-1068
Author(s):  
Mohd Nor Azmi bin Ab Patar ◽  
Takashi Komeda ◽  
Cheng Yee Low ◽  
Jamaluddin Mahmud
Keyword(s):  
Position Control ◽  
Hand Rehabilitation ◽  
Adaptation Mechanism ◽  
Robotic Exoskeleton ◽  
Lead Screw ◽  
Rehabilitation System ◽  
Normal Human ◽  
Screw Mechanism ◽  
User Friendly ◽  
Flexion And Extension

The development of a robotic exoskeleton to restore and rehab, hand and finger function is highly competitive nowadays. The robotic exoskeleton is an active actuated mechanism implemented in rehabilitation system, in which each finger attached to an instrumented lead screw mechanism allowing force and position control, according to the normal human setting. The robotic device is a direct driven actuated based on ergonomics measurements, capable to assist in flexion and extension motion. As an adaptation mechanism, it's also compatible with various sizes and shapes of anthropometric human‘s finger. The integration of DC servo motor and lead screw mechanism were the main features of the interface, which allows independent motion of the five fingers with small and lightweight actuators. The device is easily transportable, efficient safety performance, user friendly and offer multiple modes of training potentials. This paper presents the measurements implemented in the system to determine the requirements for finger and hand rehabilitation device, the design and characteristic of the whole system.

scholarly journals Design of an Observer-Based Architecture and Non-Linear Control Algorithm for Cogging Torque Reduction in Synchronous Motors

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 2077 ◽  
Author(s):  
Pierpaolo Dini ◽  
Sergio Saponara
Keyword(s):  
Control Algorithm ◽  
Permanent Magnets ◽  
Position Control ◽  
Deterministic Model ◽  
Initial Conditions ◽  
Angular Position ◽  
Observer Design ◽  
Control Technique ◽  
Servo Drive ◽  
Cogging Torque

The problem of cogging torque is due to a magnetic behavior, intrinsic to synchronous machines and due to the presence of permanent magnets themselves. Cogging torque is a significant problem when the servo drive is used for applications where high precision in terms of position control is required. In this paper we present a method of cogging torque reduction by means of a control technique based on mathematical modeling of the cogging phenomenon itself in order to exploit this knowledge directly in the controller design. The mathematical model is inserted in the dynamic model of the synchronous machine in order to exploit the feedback linearization, providing an expression of the control law in which the contribution of the deterministic knowledge of the phenomenon is directly present. The cogging phenomenon physically depends on the angular position of the rotor, as well as the deterministic model we use to define the control vector. This makes it interesting and innovative to determine whether the control algorithm can be inserted within a sensor-less architecture, where rotor position and angular velocity measurements are not available. For this purpose, we present the use of an extended Kalman filter (EKF) in the continuous-time domain, discussing the advantages of an observer design based on a dynamic motor model in three-phase and direct-square axes. Results are presented through very accurate simulation for a trajectory-tracking problem, completing with variational analysis in terms of variation of initial conditions between EKF and motor dynamics, and in terms of parametric variation to verify the robustness of the proposed algorithm. Moreover, a computational analysis based on Simulink Profiler is proposed, which provides some indication for possible implementation on an embedded platform.

scholarly journals Force-Free Control for Direct Teaching of a Surgical Assistant Robot End Effector with Wire-Driven Bidirectional Telescopic Mechanism

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3498
Author(s):  
Youqiang Zhang ◽  
Cheol-Su Jeong ◽  
Minhyo Kim ◽  
Sangrok Jin
Keyword(s):  
Control Algorithm ◽  
Position Control ◽  
Friction Model ◽  
Surgical Instruments ◽  
Control Input ◽  
End Effector ◽  
Motor Current ◽  
Direct Teaching ◽  
End Effectors ◽  
Teaching Operation

This paper shows the design and modeling of an end effector with a bidirectional telescopic mechanism to allow a surgical assistant robot to hold and handle surgical instruments. It also presents a force-free control algorithm for the direct teaching of end effectors. The bidirectional telescopic mechanism can actively transmit force both upwards and downwards by staggering the wires on both sides. In order to estimate and control torque via motor current without a force/torque sensor, the gravity model and friction model of the device are derived through repeated experiments. The LuGre model is applied to the friction model, and the static and dynamic parameters are obtained using a curve fitting function and a genetic algorithm. Direct teaching control is designed using a force-free control algorithm that compensates for the estimated torque from the motor current for gravity and friction, and then converts it into a position control input. Direct teaching operation sensitivity is verified through hand-guiding experiments.

scholarly journals Neural Network Based Contact Force Control Algorithm for Walking Robots

Sensors ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 287
Author(s):  
Byeongjin Kim ◽  
Soohyun Kim
Keyword(s):  
Neural Network ◽  
Contact Force ◽  
Force Control ◽  
Control Algorithm ◽  
Position Control ◽  
Linear Quadratic Regulator ◽  
Walking Robots ◽  
Test Model ◽  
Linear Quadratic ◽  
Contact Force Control

Walking algorithms using push-off improve moving efficiency and disturbance rejection performance. However, the algorithm based on classical contact force control requires an exact model or a Force/Torque sensor. This paper proposes a novel contact force control algorithm based on neural networks. The proposed model is adapted to a linear quadratic regulator for position control and balance. The results demonstrate that this neural network-based model can accurately generate force and effectively reduce errors without requiring a sensor. The effectiveness of the algorithm is assessed with the realistic test model. Compared to the Jacobian-based calculation, our algorithm significantly improves the accuracy of the force control. One step simulation was used to analyze the robustness of the algorithm. In summary, this walking control algorithm generates a push-off force with precision and enables it to reject disturbance rapidly.

scholarly journals The surface electromyography analysis of the non-plegic upper limb of hemiplegic subjects

2010 ◽  
Vol 68 (4) ◽  
pp. 562-566 ◽  
Author(s):  
Heloyse U Kuriki ◽  
Raquel N. de Azevedo ◽  
Augusto C. de Carvalho ◽  
Fábio Mícolis de Azevedo ◽  
Rúben F Negrão-Filho ◽  
...  
Keyword(s):  
Control Group ◽  
Electromyographic Activity ◽  
Healthy Individuals ◽  
Wrist Flexion ◽  
Functional Changes ◽  
Normal Individuals ◽  
Flexor Muscles ◽  
Stroke Group ◽  
Dominant Member ◽  
Flexion And Extension

Many authors have studied physical and functional changes in individuals post-stroke, but there are few studies that assess changes in the non-plegic side of hemiplegic subjects. This study aimed to compare the electromyographic activity in the forearm muscles of spastic patients and clinically healthy individuals, to determine if there is difference between the non-plegic side of hemiplegics and the dominant member of normal individuals. 22 hemiplegic subjects and 15 clinically healthy subjects were submitted to electromyography of the flexor and extensor carpi ulnaris muscles during wrist flexion and extension. The flexor muscles activation of stroke group (average 464.6 u.n) was significantly higher than the same muscles in control group (mean: 106.3 u.n.) during the wrist flexion, what shows that the non affected side does not present activation in the standart of normality found in the control group.

scholarly journals Design of a magnetic encoder using Hall effect

2019 ◽  
Vol 13 (2) ◽  
pp. 254-261
Author(s):  
William Alejandro López-Contreras ◽  
José Danilo Rairán-Antolines
Keyword(s):  
Hall Effect ◽  
Relative Motion ◽  
Direct Current ◽  
Permanent Magnets ◽  
Position Control ◽  
Angular Position ◽  
Linearization Method ◽  
Acquisition Process ◽  
Voltage Variation ◽  
Hall Sensors

We present the design of a magnetic encoder to measure angular position. The proposed encoder includes two Hall sensors in quadrature in a fixed platform. In addition, and over the sensors, there are two permanent magnets in a shaft. The relative motion between the fixed and the movable components generate a voltage variation in the sensors, which serve to generate the approximation of the angular position. We detail the acquisition process and the linearization method, because we consider that these are the most important contributions of this work. Lastly, we show the application of the encoder in the position control of a direct current motor to show the performance of the encoder estimating fast and slow angular position changes.

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