scholarly journals Myoelectric Control Techniques for a Rehabilitation Robot

2011 ◽  
Vol 8 (1) ◽  
pp. 21-37 ◽  
Author(s):  
Alan Smith ◽  
Edward E. Brown
Keyword(s):  
Healthy Subjects ◽  
Sagittal Plane ◽  
Robot Manipulator ◽  
Wrist Joint ◽  
Elbow Flexion ◽  
Myoelectric Control ◽  
Average Error ◽  
Rehabilitation Robot ◽  
Control Scheme ◽  
Central Cord Syndrome

This work examines two different types of myoelectric control schemes for the purpose of rehabilitation robot applications. The first is a commonly used technique based on a Gaussian classifier. It is implemented in real time for healthy subjects in addition to a subject with Central Cord Syndrome (CCS). The myoelectric control scheme is used to control three degrees of freedom (DOF) on a robot manipulator which corresponded to the robot's elbow joint, wrist joint, and gripper. The classes of motion controlled include elbow flexion and extension, wrist pronation and supination, hand grasping and releasing, and rest. Healthy subjects were able to achieve 90% accuracy. Single DOF controllers were first tested on the subject with CCS and he achieved 100%, 96%, and 85% accuracy for the elbow, gripper, and wrist controllers respectively. Secondly, he was able to control the three DOF controller at 68% accuracy. The potential applications for this scheme are rehabilitation and teleoperation. To overcome limitations in the pattern recognition based scheme, a second myoelectric control scheme is also presented which is trained using electromyographic (EMG) data derived from natural reaching motions in the sagittal plane. This second scheme is based on a time delayed neural network (TDNN) which has the ability to control multiple DOF at once. The controller tracked a subject's elbow and shoulder joints in the sagittal plane. Results showed an average error of 19° for the two joints. This myoelectric control scheme has the potential of being used in the development of exoskeleton and orthotic rehabilitation applications.

A FAT-based adaptive controller for robot manipulators without regressor matrix: theory and experiments

Robotica ◽  
2005 ◽  
Vol 24 (2) ◽  
pp. 205-210 ◽  
Author(s):  
An-Chyau Huang ◽  
Shi-Chang Wu ◽  
Wen-Fa Ting
Keyword(s):  
Function Approximation ◽  
Matrix Theory ◽  
Robot Manipulator ◽  
Nonlinear Differential Equations ◽  
Lyapunov Stability Theory ◽  
Adaptive Controller ◽  
Approximation Technique ◽  
Control Scheme ◽  
Approximation Errors ◽  
Theory And Experiments

In this paper, an adaptive control scheme is proposed for an n-link rigid robot manipulator without using the regressor. The robot is firstly modeled as a set of second-order nonlinear differential equations with the assumption that all of the matrices in that model are unavailable. Since these matrices are time-varying and their variation bounds are not given, traditional adaptive or robust designs do not apply. The function approximation technique (FAT) is used here to represent uncertainties in some finite linear combinations of orthonormal basis. The dynamics of the output tracking can thus be proved to be a stable first order filter driven by function approximation errors. Using the Lyapunov stability theory, a set of update laws is derived to give closed loop stability with proper tracking performance. Experiments are also performed on a 2-D robot to test the efficacy of the proposed scheme.

639 Maximizing Safe Positioning of Upper Extremities after Axillary Burn Injuries to Prevent Contractures and Maintain Function

2021 ◽  
Vol 42 (Supplement_1) ◽  
pp. S175-S176
Author(s):  
Connie Greiser ◽  
David Lorello ◽  
Dan Lyons ◽  
Karen J Richey ◽  
Derek Murray ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Elbow Flexion ◽  
Primary Objective ◽  
Burn Injuries ◽  
Shoulder Abduction ◽  
Shoulder Injury ◽  
Shoulder Range Of Motion ◽  
History Of ◽  
The Right ◽  
Shoulder Range

Abstract Introduction Burns crossing over a joint can result in a contracture of that joint. Axillary burns and subsequent contractures are common and may impact negatively on burn survivor rehabilitation. Positioning of burned extremities at the most lengthened position is ideal for maintenance of function and contracture prevention, 90 degrees of abduction is the most accepted position for axillary burn injuries. However, many activities of daily living require shoulder range of motion (ROM) greater than 90 degrees. The primary objective of this study was to describe and examine the incidence of paresthesia, pain, and intolerance in healthy subjects when the shoulder was placed in a position of 90 degrees or greater of shoulder abduction. Methods The subject’s nondominant upper extremity (NDE) was randomly placed in a series three of positions, including: (1) 90 degrees shoulder abduction, 30 degrees horizontal adduction with elbow extension, forearm neutral; (2) 130 degrees shoulder abduction, 30 degrees horizontal adduction, 30 degrees elbow flexion, forearm neutral; (3) 150 degrees shoulder abduction, 30 degrees horizontal adduction, 30 degrees elbow flexion, forearm neutral. Each position was maintained for a maximum of 2 hours. Subjects experiencing subjective symptoms including paresthesia lasting longer than 1 minute, pain rated greater than 3/10, and/or intolerance 2/5 was removed from the position. All subjects received at least 30 minutes of rest between positions. Results A total of 25 subjects were enrolled, mean age was 25.8 years, the majority were female (60%) and 20% had a history of NDE shoulder injury. The right arm was the dominant extremity (DE) in 88% of subjects. There were no significant differences in ROM between the DE and NDE extremity with the exception of external shoulder rotation, 94.96⁰ vs 84.8⁰ (p=.0142). Average total splint time was 136 minutes with a range of 40 – 360 minutes. Only 1 subject successfully completed all 3 splinting periods. There were 75 individual splinting events over the 3 splinting periods, and 90% of the time the splinting was stopped early. The most common reason for stopping early was paresthesia (88%) followed by pain (7%). Conclusions The positions selected represent the routine and usual care at our burn center. Patients are routinely positioned from hours to days depending on patient need. This study demonstrated that healthy subjects were unable to tolerate positioning for even two hours.

scholarly journals Design and Analysis of a Wearable Upper Limb Rehabilitation Robot with Characteristics of Tension Mechanism

2020 ◽  
Vol 10 (6) ◽  
pp. 2101 ◽  
Author(s):  
Zaixiang Pang ◽  
Tongyu Wang ◽  
Zhanli Wang ◽  
Junzhi Yu ◽  
Zhongbo Sun ◽  
...  
Keyword(s):  
Upper Limb ◽  
Human Body ◽  
Wrist Joint ◽  
Traction Force ◽  
Rehabilitation Robot ◽  
Upper Limb Rehabilitation ◽  
Freedom Of Movement ◽  
Human Arm ◽  
Toothed Belt ◽  
Limb Rehabilitation

Nowadays, patients with mild and moderate upper limb paralysis caused by cerebral apoplexy are uncomfortable with autonomous rehabilitation. In this paper, according to the “rope + toothed belt” generalized rope drive design scheme, we design a utility model for a wearable upper limb rehabilitation robot with a tension mechanism. Owing to study of the human upper extremity anatomy, movement mechanisms, and the ranges of motion, it can determine the range of motion angles of the human arm joints, and design the shoulder joint, elbow joint, and wrist joint separately under the principle of ensuring the minimum driving torque. Then, the kinematics, workspace and dynamics analysis of each structure are performed. Finally, the control system of the rehabilitation robot is designed. The experimental results show that the structure is convenient to wear on the human body, and the robot’s freedom of movement matches well with the freedom of movement of the human body. It can effectively support and traction the front and rear arms of the affected limb, and accurately transmit the applied traction force to the upper limb of the joints. The rationality of the wearable upper limb rehabilitation robot design is verified, which can help patients achieve rehabilitation training and provide an effective rehabilitation equipment for patients with hemiplegia caused by stroke.

A hybrid impedance control scheme for underwater welding robots with a passive foundation in the controller domain

SIMULATION ◽  
2017 ◽  
Vol 93 (7) ◽  
pp. 619-630 ◽  
Author(s):  
Sunil Kumar ◽  
Vikas Rastogi ◽  
Pardeep Gupta
Keyword(s):  
Minimum Distance ◽  
Position Control ◽  
Robot Manipulator ◽  
Impedance Control ◽  
Graph Model ◽  
Proportional Integral Derivative ◽  
End Effector ◽  
Flexible Arm ◽  
Control Scheme ◽  
Effective Stability

A hybrid impedance control scheme for the force and position control of an end-effector is presented in this paper. The interaction of the end-effector is controlled using a passive foundation with compensation gain. For obtaining the steady state, a proportional–integral–derivative controller is tuned with an impedance controller. The hybrid impedance controller is implemented on a terrestrial (ground) single-arm robot manipulator. The modeling is done by creating a bond graph model and efficacy is substantiated through simulation results. Further, the hybrid impedance control scheme is applied on a two-link flexible arm underwater robot manipulator for welding applications. Underwater conditions, such as hydrodynamic forces, buoyancy forces, and other disturbances, are considered in the modeling. During interaction, the minimum distance from the virtual wall is maintained. A simulation study is carried out, which reveals some effective stability of the system.

Application of non-linear H∞ control to the Tetrabot robot manipulator

1998 ◽  
Vol 212 (6) ◽  
pp. 459-465 ◽  
Author(s):  
I Postlethwaite ◽  
A Bartoszewicz
Keyword(s):  
Degrees Of Freedom ◽  
Robot Manipulator ◽  
Industrial Robot ◽  
External Disturbances ◽  
Six Degrees Of Freedom ◽  
Control Scheme ◽  
Non Linear ◽  
Modelling Uncertainties ◽  
Real Robot ◽  
Robotic Application

In this paper, an application of a non-linear H∞ control law for an industrial robot manipulator is presented. Control of the manipulator motion is formulated into a non-linear H∞ optimization problem, namely optimal tracking performance in the presence of modelling uncertainties and external disturbances. Analytical solutions for this problem are implemented on a real robot. The robot under consideration is the six-degrees-of-freedom GEC Tetrabot. Investigations are made into the selection of weights for the H∞ controller and it is shown how different selections of weights affect the Tetrabot performance. The authors believe this to be the first robotic application of nonlinear H∞ control. Comparisons of the proposed control strategy with conventional proportional-derivative and proportional-integral-derivative controllers show favourable performance of the Tetrabot under the new non-linear H∞ control scheme.

Movement Precuing Altered Reaction Time of Elbow Flexion and Forearm Supination

1987 ◽  
Vol 65 (3) ◽  
pp. 799-802 ◽  
Author(s):  
Toru Hosokawa ◽  
Ryuichi Nakamura ◽  
Yoshiaki Yamada
Keyword(s):  
Reaction Time ◽  
Healthy Subjects ◽  
Biceps Brachii ◽  
Movement Pattern ◽  
Elbow Flexion ◽  
Biceps Brachii Muscle

Electromyographic reaction time (EMG-RT) of the biceps brachii muscle for elbow flexion and forearm supination was investigated in 10 healthy subjects under two conditions of movement precuing and nonprecuing with a constant foreperiod. Analysis showed that the precuing significantly reduced EMG-RT of both movements, especially the supination, and confirmed previous finding that the supination had an advantage in initiation over the flexion when the movement pattern was prepared in advance. When not prepared, on the contrary, EMG-RT of supination significantly prolonged as compared with flexion.

Muscle Strengths and Musculoskeletal Geometry of the Upper Limb

1979 ◽  
Vol 8 (1) ◽  
pp. 41-48 ◽  
Author(s):  
A A Amis ◽  
D Dowson ◽  
V Wright
Keyword(s):  
Upper Limb ◽  
Cross Sections ◽  
Wrist Joint ◽  
Elbow Flexion ◽  
Reliable Data ◽  
Moment Arm ◽  
Joint Replacements ◽  
Moment Arms ◽  
Joint Forces

A survey of past literature has shown that there is a lack of reliable data for use in prediction of joint forces in the upper limb although this is desirable when developing joint replacements. Upper limb geometry has been analysed, leading to muscle moment arm data at the wrist and elbow. The variation of these moment arms during elbow flexion has also been examined. Analysis of the dimensions of muscles has enabled their relative strengths to be predicted, based on their ‘physiological cross-sections’. When used in conjuction with published emg data, this information will enable elbow and wrist joint forces to be estimated more realistically than has previously been possible.

scholarly journals The passive stiffness of the wrist and forearm

2012 ◽  
Vol 108 (4) ◽  
pp. 1158-1166 ◽  
Author(s):  
Domenico Formica ◽  
Steven K. Charles ◽  
Loredana Zollo ◽  
Eugenio Guglielmelli ◽  
Neville Hogan ◽  
...  
Keyword(s):  
Wrist Joint ◽  
Rehabilitation Robot ◽  
Passive Stiffness ◽  
Ulnar Deviation ◽  
The Past ◽  
Stiffness Matrices ◽  
Flexion Extension ◽  
Stiffness Characteristics ◽  
Wrist Stiffness ◽  
Rotation Dynamics

Because wrist rotation dynamics are dominated by stiffness (Charles SK, Hogan N. J Biomech 44: 614–621, 2011), understanding how humans plan and execute coordinated wrist rotations requires knowledge of the stiffness characteristics of the wrist joint. In the past, the passive stiffness of the wrist joint has been measured in 1 degree of freedom (DOF). Although these 1-DOF measurements inform us of the dynamics the neuromuscular system must overcome to rotate the wrist in pure flexion-extension (FE) or pure radial-ulnar deviation (RUD), the wrist rarely rotates in pure FE or RUD. Instead, understanding natural wrist rotations requires knowledge of wrist stiffness in combinations of FE and RUD. The purpose of this report is to present measurements of passive wrist stiffness throughout the space spanned by FE and RUD. Using a rehabilitation robot designed for the wrist and forearm, we measured the passive stiffness of the wrist joint in 10 subjects in FE, RUD, and combinations. For comparison, we measured the passive stiffness of the forearm (in pronation-supination), as well. Our measurements in pure FE and RUD agreed well with previous 1-DOF measurements. We have linearized the 2-DOF stiffness measurements and present them in the form of stiffness ellipses and as stiffness matrices useful for modeling wrist rotation dynamics. We found that passive wrist stiffness was anisotropic, with greater stiffness in RUD than in FE. We also found that passive wrist stiffness did not align with the anatomical axes of the wrist; the major and minor axes of the stiffness ellipse were rotated with respect to the FE and RUD axes by ∼20°. The direction of least stiffness was between ulnar flexion and radial extension, a direction used in many natural movements (known as the “dart-thrower's motion”), suggesting that the nervous system may take advantage of the direction of least stiffness for common wrist rotations.

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