Development of Wrist Separated Exoskeleton Socket of Myoelectric Prosthesis Hand for Symbrachydactyly.

In recent years, the functionality of myoelectric prosthetic hands has improved as motors have become smaller and controls have become more advanced. Attempts have been made to reproduce the rotation and flexion of the wrist by adding degrees of freedom to the wrist joint. However, it is still difficult to fully reproduce the functionality of the wrist joint owing to the weight of the prosthesis and size limitations.

A Hand Gesture Recognition Strategy Based on Virtual-Dimension Increase of EMG.

The electromyography(EMG) signal is the biocurrent associated with muscle contraction and can be used as the input signal to a myoelectric intelligent bionic hand to control different gestures of the hand. Increasing the number of myoelectric-signal channels can yield richer information of motion intention and improve the accuracy of gesture recognition. However, as the number of acquisition channels increases, its effect on the improvement of the accuracy of gesture recognition gradually diminishes, resulting in the improvement of the control effect reaching a plateau.

Research status of elderly-care robots and safe human-robot interaction methods.

Faced with the increasingly severe global aging population with fewer children, the research, development, and application of elderly-care robots are expected to provide some technical means to solve the problems of elderly care, disability and semi-disability nursing, and rehabilitation. Elderly-care robots involve biomechanics, computer science, automatic control, ethics, and other fields of knowledge, which is one of the most challenging and most concerned research fields of robotics. Unlike other robots, elderly-care robots work for the frail elderly.

Comparison of Bipolar and Monopolar Electrode Configurations for FES on Biceps Brachii.

Function electrical stimulation (FES) is recommended as one of the effective methods for rehabilitation of motor function after stroke. There are two forms to deliver electrical stimulation to induce muscle contraction: Bipolar electrode configuration with two electrodes of the same size, and monopolar electrode configuration with a bigger electrode as an indifferent electrode and a smaller one as an active electrode. The purpose of this study is to compare the two kinds of configuration on biceps brachii in terms of induced muscle contraction force and muscle fatigue.

Highly Anthropomorphic Finger Design With a Novel Friction Clutch for Achieving Human-Like Reach-and-Grasp Movements.

In the design of prosthetic hand fingers, achieving human-like movement while meeting anthropomorphic demands such as appearance, size, and lightweight is quite challenging. Human finger movement involves two distinct motion characters during natural reach-and-grasp tasks: consistency in the reaching stage and adaptability in the grasping stage. The former one enhances grasp stability and reduces control complexity; the latter one promotes the adaptability of finger to various objects.

Novel prosthesis with proximity sensor for upper extremity phocomelia.

We herein report on the application of a novel motorized prosthetic hand in a child with upper extremity phocomelia.

High-precision dynamic torque control of high stiffness actuator for humanoids.

The high stiffness actuator (HSA), applied to each joint of an electrical driven humanoid robot, can directly affect the motion performance of the torque-controlled humanoid robots. For high control performance of HSA, a high-precision dynamic torque control (HDTC) is proposed. The HDTC consists of two phases: (1) A novel dynamic current control is used to linearize high stiffness actuator torque control system, which can estimate and compensate the nonlinear coupling parts; (2) An enhanced internal model control is designed to ensure high tracking accuracy in the system containing noisy torque signal and even numerical differentiation signals.

Improvement of Precision Grasping Performance by Interaction Between Soft Finger Pulp and Hard Nail.

In this study, we investigated the effect of the presence or absence of fingernails on precision grasping using artificial anthropomimetic fingers. We hypothesized that fingernails improve precision grasping performance by increasing the friction coefficient while suppressing fingertip deformation. To test our hypothesis, we developed artificial fingertips, each composed of bone, nail, skin, and soft tissue, and fabricated three types of artificial fingers with different skin softness grades and artificial fingers without nails as the control condition.

Coevolution of Myoelectric Hand Control under the Tactile Interaction among Fingers and Objects.

The usability of a prosthetic hand differs significantly from that of a real hand. Moreover, the complexity of manipulation increases as the number of degrees of freedom to be controlled increases, making manipulation with biological signals extremely difficult. To overcome this problem, users need to select a grasping posture that is adaptive to the object and a stable grasping method that prevents the object from falling.

Learning Data Correction for Myoelectric Hand Based on "Survival of the Fittest".

In recent years, myoelectric hands have become multi-degree-of-freedom (DOF) devices, which are controlled via machine learning methods. However, currently, learning data for myoelectric hands are gathered manually and thus tend to be of low quality. Moreover, in the case of infants, gathering accurate learning data is nearly impossible because of the difficulty of communicating with them.

Towards Optimizing the Quality of Long-Term Physiological Signals Monitoring by Using Anhydrous Carbon Paste Electrode.

Long-term physiological signal monitoring is very important for the diagnosis of health conditions that occur randomly and cannot be easily detected by a short period of a hospital visit. However, the conventional wet electrodes suffered from the problem of signal quality degradation due to the gradual dehydration of the conductive gel. An anhydrous carbon paste electrode (CPE) constructed by a composite of carbon black and polydimethylsiloxane was proposed to enable long-term physiological signal monitoring without signal quality degradation as time elapses.

Design of an Effective Prosthetic Hand System for Adaptive Grasping with the Control of Myoelectric Pattern Recognition Approach.

In this paper, we develop a prosthetic bionic hand system to realize adaptive gripping with two closed-loop control loops by using a linear discriminant analysis algorithm (LDA). The prosthetic hand contains five fingers and each finger is driven by a linear servo motor. When grasping objects, four fingers except the thumb would adjust automatically and bend with an appropriate gesture, while the thumb is stretched and bent by the linear servo motor.

Investigation of Motor Point Shift and Contraction Force of Triceps Brachii for Functional Electrical Stimulation.

Functional electrical stimulation (FES) has been used for neurorehabilitation of individuals with paralysis due to spinal cord injuries or stroke aftereffects. The biceps brachii is often adopted in studies on FES because of the ease of stimulation, while there are few studies on the triceps brachii. Stimulation of the triceps brachii is important because the biceps brachii tends to be spastic.

A 3-DOF Bionic Waist Joint for Humanoid Robot.

In this study, a 3 degree-of-freedom bionic waist joint was developed with coupled tendon-driven mechanism. This bionic waist joint can not only ensure the safety of the human-robot interface, but also increase the load capacity without increasing the weight. The coupled tendon-driven mechanism enables the motion of each joint to be driven by at least two motors together, and enables a maximum torque of 3 times the maximum motor output torque at each joint.

A Study on the Classification Effect of sEMG Signals in Different Vibration Environments Based on the LDA Algorithm.

Myoelectric prosthesis has become an important aid to disabled people. Although it can help people to recover to a nearly normal life, whether they can adapt to severe working conditions is a subject that is yet to be studied. Generally speaking, the working environment is dominated by vibration.

Survey on Main Drive Methods Used in Humanoid Robotic Upper Limbs.

Humanoid robotic upper limbs including the robotic hand and robotic arm are widely studied as the important parts of a humanoid robot. A robotic upper limb with light weight and high output can perform more tasks. The drive system is one of the main factors affecting the weight and output of the robotic upper limb, and therefore, the main purpose of this study is to compare and analyze the effects of the different drive methods on the overall structure.

Asymmetric shape of distal phalanx of human finger improves precision grasping.

In morphology field, the functions of an asymmetric-shaped distal phalanx in human finger have only been inferred. In this study, we used an engineering approach to empirically examine the effects of the shape of distal phalanx on the ability of precision grasping. Hence, we developed artificial fingertips consisting of four parts, namely bones, nails, skin, and subcutaneous tissue, that substitute the actual human fingertips.

Adaptive Neural Network Control of a Flexible Spacecraft Subject to Input Nonlinearity and Asymmetric Output Constraint.

This article focuses on the vibration reducing and angle tracking problems of a flexible unmanned spacecraft system subject to input nonlinearity, asymmetric output constraint, and system parameter uncertainties. Using the backstepping technique, a boundary control scheme is designed to suppress the vibration and regulate the angle of the spacecraft. A modified asymmetric barrier Lyapunov function is utilized to ensure that the output constraint is never transgressed.

Semi-Automated Control System for Reaching Movements in EMG Shoulder Disarticulation Prosthesis Based on Mixed Reality Device.

: The development of a control system for an electromyographic shoulder disarticulation (EMG-SD) prosthesis to rapidly achieve a task with a reduction in the operational failure of the user. : The motion planning of an EMG-SD prosthesis was automated using measured visual information through a mixed reality device. The detection of an object to be grasped and motion execution depended on the EMG of the user, which gives voluntary controllability and makes the system semi-automated.

Joint angle based motor point tracking stimulation for surface FES: A Study on biceps brachii.

Functional electrical stimulation (FES) has been an effective treatment option in clinical rehabilitation such as motor function recovery after stroke. The main limitation of FES is the lack of stimulation efficiency in motor unit recruitment compared with voluntary contractions, which may cause the early onset of muscle fatigue. The stimulation efficiency of FES can be improved by optimizing electrode positions to target the motor point (MP).

Development of a Shoulder Disarticulation Prosthesis System Intuitively Controlled With the Trunk Surface Electromyogram.

We developed an intuitively operational shoulder disarticulation prosthesis system that can be used without long-term training. The developed system consisted of four degrees of freedom joints, as well as a user adapting control system based on a machine learning technique and surface electromyogram (EMG) of the trunk. We measured the surface EMG of the trunk of healthy subjects at multiple points and analyzed through principal component analysis to identify the proper EMG measurement portion of the trunk, which was determined to be distributed in the chest and back.

SEMG Feature Extraction Based on StockwellTransform Improves Hand MovementRecognition Accuracy.

Feature extraction, as an important method for extracting useful information from surfaceelectromyography (SEMG), can significantly improve pattern recognition accuracy. Time andfrequency analysis methods have been widely used for feature extraction, but these methods analyzeSEMG signals only from the time or frequency domain. Recent studies have shown that featureextraction based on time-frequency analysis methods can extract more useful information fromSEMG signals.