scholarly journals Development of Multifunctional Myoelectric Hand Prosthesis System with Easy and Effective Mode Change Control Method Based on the Thumb Position and State

2021 ◽  
Vol 11 (16) ◽  
pp. 7295
Author(s):  
Sung-Yoon Jung ◽  
Seung-Gi Kim ◽  
Joo-Hyung Kim ◽  
Se-Hoon Park
Keyword(s):  
Upper Limb ◽  
Control Algorithm ◽  
Degrees Of Freedom ◽  
Control Method ◽  
Effective Control ◽  
Hand Gestures ◽  
Mode Change ◽  
Hand Prosthesis ◽  
Six Dof ◽  
Flexion And Extension

Commercial multi-degrees-of-freedom (multi-DOF) myoelectric hand prostheses can perform various hand gestures and grip motions using multiple DOFs. However, as most upper limb amputees have less than two electromyogram (EMG) signals generated at the amputation site, it is difficult to control various hand gestures and grip motions using multi-DOF myoelectric hand prostheses. This paper proposes a multifunctional myoelectric hand prosthesis system that uses only two EMG sensors while improving the convenience of upper limb amputees in everyday life. The proposed system comprises a six-DOF myoelectric hand prosthesis and an easy and effective control algorithm that enables upper limb amputees to perform various hand gestures and grip motions. More specifically, the hand prosthesis has a multi-DOF five-finger mechanism and a small controller that can be mounted inside the hand, allowing it to perform various hand gestures and grip motions. The control algorithm facilitates four grip motions and four gesture motions using the adduction and abduction positions of the thumb, the flexion and extension state of the thumb, and three EMG signals (co-contraction, flexion, and extension) generated using the two EMG sensors. Experimental results indicate that the proposed system is a versatile, flexible, and effective hand prosthesis system for upper limb amputees.

scholarly journals A 4-DOF Upper Limb Exoskeleton for Physical Assistance: Design, Modeling, Control and Performance Evaluation

2021 ◽  
Vol 11 (13) ◽  
pp. 5865
Author(s):  
Muhammad Ahsan Gull ◽  
Mikkel Thoegersen ◽  
Stefan Hein Bengtson ◽  
Mostafa Mohammadi ◽  
Lotte N. S. Andreasen Struijk ◽  
...  
Keyword(s):  
Upper Limb ◽  
Tracking Control ◽  
Degrees Of Freedom ◽  
Control Method ◽  
Mechanical Design ◽  
Trajectory Tracking Control ◽  
Upper Limb Exoskeleton ◽  
And Performance ◽  
Physically Disabled People ◽  
Human Upper Limb

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.

scholarly journals Extending model-mediation method to multi-degree-of-freedom teleoperation systems experiencing time delays in communication

Robotica ◽  
2015 ◽  
Vol 35 (5) ◽  
pp. 1121-1136 ◽  
Author(s):  
Emre Uzunoğlu ◽  
Mehmet İsmet Can Dede
Keyword(s):  
Time Delays ◽  
Control Algorithm ◽  
Degrees Of Freedom ◽  
Control Method ◽  
Test Results ◽  
Bilateral Teleoperation ◽  
Extended Version ◽  
Teleoperation System ◽  
Teleoperation Systems ◽  
Three Degrees Of Freedom

SUMMARYIn this study, a bilateral teleoperation control algorithm is developed in which the model-mediation method is integrated with an impedance controller. The model-mediation method is also extended to three-degrees-of-freedom teleoperation. The aim of this controller is to compensate for instability issues and excessive forcing applied to the slave environment stemming from time delays in communication. The proposed control method is experimentally tested with two haptic desktop devices. Test results indicate that stability and passivity of the bilateral teleoperation system is preserved under variable time delays in communication. It is also observed that safer interactions of the slave system with its environment can be achieved by utilizing an extended version of the model-mediation method with an impedance controller.

scholarly journals Discrete action control for prosthetic digits

2020 ◽  
Author(s):  
Agamemnon Krasoulis ◽  
Kianoush Nazarpour
Keyword(s):  
Upper Limb ◽  
Degrees Of Freedom ◽  
Motion Tracking ◽  
Position Control ◽  
Ground Truth ◽  
Action Control ◽  
Time Step ◽  
Upper Limb Prostheses ◽  
Discrete Action ◽  
Six Dof

AbstractObjectiveWe aim to develop a paradigm for simultaneous and independent control of multiple degrees of freedom (DOFs) for upper-limb prostheses.ApproachWe introduce action control, a novel method to operate prosthetic digits with surface electromyography (EMG) based on multi-label, multi-class classification. At each time step, the decoder classifies movement intent for each controllable DOF into one of three categories: open, close, or stall (i.e., no movement). We implemented a real-time myoelectric control system using this method and evaluated it by running experiments with one unilateral and two bilateral amputees. Participants controlled a six-DOF bar interface on a computer display, with each DOF corresponding to a motor function available in multi-articulated prostheses.Main resultsWe show that action control can significantly and systematically outperform the state-of-the-art method of position control via multi-output regression in both task- and non-task-related measures. Improvements in median task performance ranged from 20.14% to 62.32% for individual participants. Analysis of a post-experimental survey revealed that all participants rated action higher than position control in a series of qualitative questions and expressed an overall preference for the former.SignificanceAction control has the potential to improve the dexterity of upper-limb prostheses. In comparison with regression-based systems, it only requires discrete instead of real-valued ground truth labels, typically collected with motion tracking systems. This feature makes the system both practical in a clinical setting and also suitable for bilateral amputation. This work is the first demonstration of myoelectric digit control in bilateral upper-limb amputees. Further investigation and pre-clinical evaluation are required to assess the translational potential of the method.

scholarly journals Development of an armored upper limb exoskeleton

2019 ◽  
pp. 109-117
Author(s):  
Santiago López-Méndez ◽  
Hader Vladimir Martínez-Tejada ◽  
Marco Fidel Valencia-García
Keyword(s):  
Upper Limb ◽  
Metal Matrix ◽  
Degrees Of Freedom ◽  
New Technologies ◽  
Personal Safety ◽  
Critical Aspect ◽  
Upper Limb Exoskeleton ◽  
The Military ◽  
Three Degrees Of Freedom ◽  
Flexion And Extension

Personal safety is a critical aspect of daily life, but also in the military. Active soldiers often have to carry heavy gear during missions, which puts pressure on their backs. Therefore, the military must come up with new technologies that allow both protection and movement. In this paper, it is explaining the development of an armored upper limb exoskeleton with three degrees of freedom. To ensure portability, it is used battery-fed DC actuators. The system was encased in a metal matrix that doubles up as a protective plate. The exoskeleton, the control system, the actuators, and the plate are integrated so that they offer protection while supporting the flexion and extension of the upper limb.

scholarly journals Control of Upper Limb Active Prosthesis Using Surface Electromyography

2021 ◽  
Vol 15 ◽  
pp. 92-96
Author(s):  
Muhammad Asim Waris ◽  
Mohsin Jamil ◽  
Syed Omer Gilani ◽  
Yasar Ayaz
Keyword(s):  
Upper Limb ◽  
Neural Activity ◽  
Surface Electromyography ◽  
Degrees Of Freedom ◽  
Noise Levels ◽  
Maximum Surface ◽  
Emg Signal ◽  
Human Arm ◽  
Practical Demonstration ◽  
Flexion And Extension

Electromyographic prosthesis with higher degrees of freedom is an expanding area of research. In this paper, active prosthesis with four degrees of freedom has been investigated, which can be used to fit a limb with amputation below elbow. The system comprises of multichannel inputs which correspond to the flexion and extension as well as supination and pronation. To find maximum surface neural activity, accurate placement of electrodes has been carried out on 10 subjects aged between 22-30 years. Signals (0-500 hertz) acquired from contracting voluntary muscles with minimum cross talk and common mode noise. Clean filtered EMG signal is then amplified precisely. Finally digitization is being done to drive bionic hand. Practical demonstration on a simple DC motor proved providential using this method for the two motions of an actual human arm. EMG Signals emanating from muscles dedicated to individual fingers have been recorded. Moreover modern classifiers; KNN and NN have been investigated carefully with selected features through different time and noise levels.

scholarly journals Hybrid Impedance-Admittance Control for Upper Limb Exoskeleton Using Electromyography

2020 ◽  
Vol 10 (20) ◽  
pp. 7146
Author(s):  
Lucas D. L. da Silva ◽  
Thiago F. Pereira ◽  
Valderi R. Q. Leithardt ◽  
Laio O. Seman ◽  
Cesar A. Zeferino
Keyword(s):  
Upper Limb ◽  
Degrees Of Freedom ◽  
Control Method ◽  
Hybrid Control ◽  
Impedance Control ◽  
Robotic Arm ◽  
Average Error ◽  
Acceptable Error ◽  
Upper Limb Exoskeleton ◽  
Input Signals

Exoskeletons are wearable mobile robots that combine various technologies to enable limb movement with greater strength and endurance, being used in several application areas, such as industry and medicine. In this context, this paper presents the development of a hybrid control method for exoskeletons, combining admission and impedance control based on electromyographic input signals. A proof of concept of a robotic arm with two degrees of freedom, mimicking the functions of a human’s upper limb, was built to evaluate the proposed control system. Through tests that measured the discrepancy between the angles of the human joint and the joint of the exoskeleton, it was possible to determine that the system remained within an acceptable error range. The average error is lower than 4.3%, and the robotic arm manages to mimic the movements of the upper limbs of a human in real-time.

Application Study on Finger Joint Motion in Rehabilitation Training

2014 ◽  
Vol 644-650 ◽  
pp. 879-883
Author(s):  
Jing Jing Yu
Keyword(s):  
Control Method ◽  
Finger Joint ◽  
Continuous Passive Motion ◽  
Joint Motion ◽  
Joint Movement ◽  
Rehabilitation Training ◽  
Angle Data ◽  
Finger Flexion ◽  
And Control ◽  
Flexion And Extension

In various forms of movement of finger rehabilitation training, Continuous Passive Motion (CPM) of single degree of freedom (1 DOF) has outstanding application value. Taking classic flexion and extension movement for instance, this study collected the joint angle data of finger flexion and extension motion by experiments and confirmed that the joint motion of finger are not independent of each other but there is certain rule. This paper studies the finger joint movement rule from qualitative and quantitative aspects, and the conclusion can guide the design of the mechanism and control method of finger rehabilitation training robot.

scholarly journals Torque Ripple Suppression of PMSM Based on Robust Two Degrees-of-Freedom Resonant Controller

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1015
Author(s):  
Mingfei Huang ◽  
Yongting Deng ◽  
Hongwen Li ◽  
Jing Liu ◽  
Meng Shao ◽  
...  
Keyword(s):  
Control Strategy ◽  
Measurement Errors ◽  
Degrees Of Freedom ◽  
Control Method ◽  
Torque Ripple ◽  
Current Loop ◽  
Two Degrees Of Freedom ◽  
Robust Stability Analysis ◽  
Resonant Controller ◽  
Testing Environments

This paper concentrates on a robust resonant control strategy of a permanent magnet synchronous motor (PMSM) for electric drivers with model uncertainties and external disturbances to improve the control performance of the current loop. Firstly, to reduce the torque ripple of PMSM, the resonant controller with fractional order (FO) calculus is introduced. Then, a robust two degrees-of-freedom (Robust-TDOF) control strategy was designed based on the modified resonant controller. Finally, by combining the two control methods, this study proposes an enhanced Robust-TDOF regulation method, named as the robust two degrees-of-freedom resonant controller (Robust-TDOFR), to guarantee the robustness of model uncertainty and to further improve the performance with minimized periodic torque ripples. Meanwhile, a tuning method was constructed followed by stability and robust stability analysis. Furthermore, the proposed Robust-TDOFR control method was applied in the current loop of a PMSM to suppress the periodic current harmonics caused by non-ideal factors of inverter and current measurement errors. Finally, simulations and experiments were performed to validate our control strategy. The simulation and experimental results showed that the THDs (total harmonic distortion) of phase current decreased to a level of 0.69% and 5.79% in the two testing environments.

scholarly journals A New Model Predictive Control Method for Eliminating Hydraulic Oscillation and Dynamic Hydraulic Imbalance in a Complex Chilled Water System

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3608
Author(s):  
Yang Yuan ◽  
Neng Zhu ◽  
Haizhu Zhou ◽  
Hai Wang
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Control Method ◽  
Water System ◽  
Energy Performance ◽  
Effective Control ◽  
New Model ◽  
Chilled Water ◽  
Chilled Water System ◽  
Hydraulic Oscillation

To enhance the energy performance of a central air-conditioning system, an effective control method for the chilled water system is always essential. However, it is a real challenge to distribute exact cooling energy to multiple terminal units in different floors via a complex chilled water network. To mitigate hydraulic imbalance in a complex chilled water system, many throttle valves and variable-speed pumps are installed, which are usually regulated by PID-based controllers. Due to the severe hydraulic coupling among the valves and pumps, the hydraulic oscillation phenomena often occur while using those feedback-based controllers. Based on a data-calibrated water distribution model which can accurately predict the hydraulic behaviors of a chilled water system, a new Model Predictive Control (MPC) method is proposed in this study. The proposed method is validated by a real-life chilled water system in a 22-floor hotel. By the proposed method, the valves and pumps can be regulated safely without any hydraulic oscillations. Simultaneously, the hydraulic imbalance among different floors is also eliminated, which can save 23.3% electricity consumption of the pumps.

Robust Control Method Based on Machine Learning for Boiler Combustion System

2014 ◽  
Vol 685 ◽  
pp. 368-372 ◽  
Author(s):  
Hao Zhang ◽  
Ya Jie Zhang ◽  
Yan Gu Zhang
Keyword(s):  
Robust Control ◽  
Intelligent Control ◽  
Pid Control ◽  
Control Algorithm ◽  
Control Method ◽  
Support Vector ◽  
Control Performance ◽  
Fuzzy Pid Control ◽  
On Line ◽  
Control Output

In this study, we presented a boiler combustion robust control method under load changes based on the least squares support vector machine, PID parameters are on-line adjusted and identified by LSSVM, optimum control output is obtained. The simulation result shows control performance of the intelligent control algorithm is superior to traditional control algorithm and fuzzy PID control algorithm, the study provides a new control method for strong non-linear boiler combustion control system.

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