scholarly journals A Finger Grip Force Sensor with an Open-Pad Structure for Glove-Type Assistive Devices

Sensors ◽  
2019 ◽  
Vol 20 (1) ◽  
pp. 4 ◽  
Author(s):  
Junghoon Park ◽  
Pilwon Heo ◽  
Jung Kim ◽  
Youngjin Na
Keyword(s):  
Degrees Of Freedom ◽  
Grip Force ◽  
Force Sensor ◽  
Assistive Devices ◽  
Finger Joint ◽  
Assistive Device ◽  
Force Estimation ◽  
Joint Angles ◽  
Fingertip Force ◽  
Grasping Force

This paper presents a fingertip grip force sensor based on custom capacitive sensors for glove-type assistive devices with an open-pad structure. The design of the sensor allows using human tactile sensations during grasping and manipulating an object. The proposed sensor can be attached on both sides of the fingertip and measure the force caused by the expansion of the fingertip tissue when a grasping force is applied to the fingertip. The number of measurable degrees of freedom (DoFs) are the two DoFs (flexion and adduction) for the thumb and one DoF (flexion) for the index and middle fingers. The proposed sensor allows the combination with a glove-type assistive device to measure the fingertip force. Calibration was performed for each finger joint angle because the variations in the expansion of the fingertip tissue depend on the joint angles. The root mean square error (RMSE) for fingertip force estimation ranged from 3.75% to 9.71% after calibration, regardless of the finger joint angles or finger posture.

Fingertip Force Measurement of GloveMAP by Using a Flexi Force Sensor

2015 ◽  
Vol 780 ◽  
pp. 1-5
Author(s):  
Khairunizam Wan ◽  
H.E. Nabilah ◽  
Nor Farahiya ◽  
M. Hazwan Ali ◽  
Rashidah Suhaimi ◽  
...  
Keyword(s):  
Force Measurement ◽  
Current Trend ◽  
Force Sensor ◽  
Force Sensors ◽  
Gaussian Filter ◽  
Natural Interaction ◽  
Fingertip Force ◽  
Grasping Force ◽  
Interface Devices ◽  
A Current

Modernization of human technologies overtime results the need of more freedom technology likes the use of natural interaction to replace a current trend interface devices such as joysticks, mice, keyboards and other related output devices. Dataglove is one of the interface devices that could serve a natural interaction between user and computers. In this paper, a dataglove called GloveMAP is introduced which has the capability of measuring fingertip force. The flexible force sensors are attached to the fingers location of the glove. Several object grasping experiments are conducted and the grasping force signals are measured. A Gaussian filter is introduced to smoothen the acquired force signals.

Hybrid Position and Force Control Without Force Sensor

1996 ◽  
Vol 8 (3) ◽  
pp. 226-234
Author(s):  
Kiyoshi Ohishi ◽  
◽  
Masaru Miyazaki ◽  
Masahiro Fujita ◽  
Keyword(s):  
Degrees Of Freedom ◽  
Inverse Dynamics ◽  
Hybrid Control ◽  
Robot Manipulator ◽  
Reaction Force ◽  
Force Sensor ◽  
Force Estimation ◽  
Estimation System ◽  
Dynamics Calculation ◽  
Torque Observer

Generally, hybrid control is realized by sensor signal feedback of position and force. However, some robot manipulators do not have a force sensor due to the environment. Moreover, a precise force sensor is very expensive. In order to overcome these problems, we propose the estimation system of reaction force without using a force sensor. This system consists of the torque observer and the inverse dynamics calculation. Using both this force estimation system and <I>H</I>∞ acceleration controller which is based on <I>H</I>∞ control theory, it takes into account the frequency characteristics of both sensor noise effect and disturbance rejection. The experimental results in this paper illustrate the fine hybrid control of the three tested degrees-of-freedom DD robot manipulator without force sensor.

314 External force estimation for robot hand without grasping-force sensor

2005 ◽  
Vol 2005.42 (0) ◽  
pp. 97-98
Author(s):  
Takeshi TORITA ◽  
Ryoichi SUZUKI ◽  
Nobuaki KOBAYASHI
Keyword(s):  
External Force ◽  
Force Sensor ◽  
Robot Hand ◽  
Force Estimation ◽  
Grasping Force

Using a saddle-assistive device equipped with mechanical orthosis for walking of the person with incomplete spinal cord injury

2021 ◽  
pp. 095441192110201
Author(s):  
Akbar Hojjati Najafabadi ◽  
Saeid Amini ◽  
Farzam Farahmand
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Reaction Force ◽  
Assistive Devices ◽  
Assistive Device ◽  
Walking Ability ◽  
Vertical Force ◽  
Incomplete Spinal Cord Injury ◽  
Combined Application ◽  
Cord Injury

The majority of the people with incomplete spinal cord injury lose their walking ability, due to the weakness of their muscle motors in providing torque. As a result, developing assistive devices to improve their conditionis of great importance. In this study, a combined application of the saddle-assistive device (S-AD) and mechanical medial linkage or thosis was evaluated to improve the walking ability in patients with spinal cord injury in the gait laboratory. This mobile assistive device is called the saddle-assistive device equipped with medial linkage or thosis (S-ADEM). In this device, a mechanical orthosis was used in a wheeled walker as previously done in the literature. Initially, for evaluation of the proposed assistive device, the experimental results related to the forces and torques exerted on the feet and upper limbs of a person with the incomplete Spinal Cord Injury (SCI) during walking usingthe standard walker were compared with an those obtained from using the S-ADEM on an able-bodied subject. It was found that using this combination of assistive devices decreases the vertical force and torque on the foot at the time of walking by 53% and 48%, respectively compared to a standard walker. Moreover, the hand-reaction force on the upper limb was negligible instanding and walking positions usingthe introduced device. The findings of this study revealed that the walking ability of the patients with incomplete SCI was improved using the proposed device, which is due to the bodyweight support and the motion technology used in it.

scholarly journals Identical Limb Dynamics for Unilateral Impairments through Biomechanical Equivalence

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 705
Author(s):  
Fatemeh Rasouli ◽  
Kyle B. Reed
Keyword(s):  
Mathematical Model ◽  
Numerical Solution ◽  
Dynamic Models ◽  
Assistive Devices ◽  
Assistive Device ◽  
Human Walking ◽  
Physical Parameters ◽  
Gait Rehabilitation ◽  
And Performance ◽  
Two Sides

Dynamic models, such as double pendulums, can generate similar dynamics as human limbs. They are versatile tools for simulating and analyzing the human walking cycle and performance under various conditions. They include multiple links, hinges, and masses that represent physical parameters of a limb or an assistive device. This study develops a mathematical model of dissimilar double pendulums that mimics human walking with unilateral gait impairment and establishes identical dynamics between asymmetric limbs. It introduces new coefficients that create biomechanical equivalence between two sides of an asymmetric gait. The numerical solution demonstrates that dissimilar double pendulums can have symmetric kinematic and kinetic outcomes. Parallel solutions with different physical parameters but similar biomechanical coefficients enable interchangeable designs that could be incorporated into gait rehabilitation treatments or alternative prosthetic and ambulatory assistive devices.

Polymer optical fiber-embedded force sensor system for assistive devices with dynamic compensation

2021 ◽  
pp. 1-1
Author(s):  
Leticia Avellar ◽  
Gabriel Delgado ◽  
Eduardo Rocon ◽  
Carlos Marques ◽  
Anselmo Frizera ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Force Sensor ◽  
Assistive Devices ◽  
Sensor System ◽  
Polymer Optical Fiber ◽  
Dynamic Compensation

scholarly journals An Electro-Oculogram Based Vision System for Grasp Assistive Devices—A Proof of Concept Study

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4515
Author(s):  
Rinku Roy ◽  
Manjunatha Mahadevappa ◽  
Kianoush Nazarpour
Keyword(s):  
Vision System ◽  
Extraction Procedure ◽  
Orientation Angle ◽  
Object Orientation ◽  
Assistive Devices ◽  
Assistive Device ◽  
Vision Systems ◽  
Signature Extraction ◽  
Voluntary Muscle ◽  
Als Patients

Humans typically fixate on objects before moving their arm to grasp the object. Patients with ALS disorder can also select the object with their intact eye movement, but are unable to move their limb due to the loss of voluntary muscle control. Though several research works have already achieved success in generating the correct grasp type from their brain measurement, we are still searching for fine controll over an object with a grasp assistive device (orthosis/exoskeleton/robotic arm). Object orientation and object width are two important parameters for controlling the wrist angle and the grasp aperture of the assistive device to replicate a human-like stable grasp. Vision systems are already evolved to measure the geometrical attributes of the object to control the grasp with a prosthetic hand. However, most of the existing vision systems are integrated with electromyography and require some amount of voluntary muscle movement to control the vision system. Due to that reason, those systems are not beneficial for the users with brain-controlled assistive devices. Here, we implemented a vision system which can be controlled through the human gaze. We measured the vertical and horizontal electrooculogram signals and controlled the pan and tilt of a cap-mounted webcam to keep the object of interest in focus and at the centre of the picture. A simple ‘signature’ extraction procedure was also utilized to reduce the algorithmic complexity and system storage capacity. The developed device has been tested with ten healthy participants. We approximated the object orientation and the size of the object and determined an appropriate wrist orientation angle and the grasp aperture size within 22 ms. The combined accuracy exceeded 75%. The integration of the proposed system with the brain-controlled grasp assistive device and increasing the number of grasps can offer more natural manoeuvring in grasp for ALS patients.

Application of Sit-To-Stand Assistive Device Based on Hip Support

2021 ◽  
Vol 14 ◽  
Author(s):  
Huaiqiang Zhang ◽  
Qiang Xue ◽  
Shuo Yang ◽  
Tongtong Wang ◽  
Binwei Zhou
Keyword(s):  
Lower Limb ◽  
Independent Living ◽  
Structural Characteristics ◽  
Assistive Devices ◽  
Assistive Device ◽  
Technology Application ◽  
Assist Devices ◽  
Advantages And Disadvantages ◽  
Sit To Stand

Background: Completing the transition from a sitting position to a standing position is a basic skill in people’s daily lives and is crucial for independent living. Lower limb dysfunction will bring many inconveniences into a person’s life and greatly affect their quality of life. Patients with lower limb dysfunction are a specialized group, and nursing problems for this group are becoming increasingly serious. Helping patients with lower limb dysfunction restore their lower limb mobility or assisting them to walk is a social problem necessary to be solved. Objective: : To review the recent sit-to-stand assistive devices based on hip support, classify them systematically and introduce their characteristics, including the mechanisms and the types of patients for which such mechanisms are applicable; to help patients with lower limb dysfunction or doctors (therapists) understand and choose a reasonable sit-to-stand assist device based on hip support. Methods: This paper summarizes literatures and patents about sit-to-stand assistive devices. From the aspects of structural characteristics, drive type and support modes based on the hip and applications situation, the advantages and disadvantages of the typical sit-to-stand assist devices are represented. Results: Current and future development trends on the structural characteristics, drive type and support modes based on the hip and applications situation of sit-to-stand assist devices are discussed to improve the humanization, modularization and applicability of sit-to-stand assist devices. Conclusion: Sit-to-stand assistive devices based on hip support can help patients improve the quality of their life, assist patients carrying out rehabilitation training, and delay the decline of lower limb function. However, the existing sit-to-stand assistive devices based on hip support need further improvement in the aspects of motion mechanism, new technology application and ergonomics design.

A Model of the Human Spine: Forward and Inverse Kinematics

1992 ◽  
Author(s):  
Sunil Kumar Agrawal ◽  
Siyan Li ◽  
Glen Desmier
Keyword(s):  
Range Of Motion ◽  
Inverse Kinematics ◽  
Degrees Of Freedom ◽  
Kinematic Model ◽  
Joint Angles ◽  
Human Spine ◽  
Forward And Inverse Kinematics ◽  
Position And Orientation ◽  
Three Degrees Of Freedom ◽  
Adjacent Vertebra

Abstract The human spine is a sophisticated mechanism consisting of 24 vertebrae which are arranged in a series-chain between the pelvis and the skull. By careful articulation of these vertebrae, a human being achieves fine motion of the skull. The spine can be modeled as a series-chain with 24 rigid links, the vertebrae, where each vertebra has three degrees-of-freedom relative to an adjacent vertebra. From the studies in the literature, the vertebral geometry and the range of motion between adjacent vertebrae are well-known. The objectives of this paper are to present a kinematic model of the spine using the available data in the literature and an algorithm to compute the inter vertebral joint angles given the position and orientation of the skull. This algorithm is based on the observation that the backbone can be described analytically by a space curve which is used to find the joint solutions..

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